Good morning. Welcome to the Wave Life Sciences Analyst and Investor Research Webcast. At this time, all participants are in a listen-only mode. As a reminder, this call is being recorded and webcast. I'll now turn the call over to Kate Rausch, Head of Investor Relations at Wave Life Sciences. Please go ahead.
Thank you, operator. Good morning. Welcome to Wave's 2020 Analyst and Investor Research Webcast. The slide presentation that accompanies this webcast is available in the Investors section of our website at www.wavelifesciences.com. Before we begin, I would like to remind you that management may be making forward-looking statements during today's presentation. These statements are subject to a number of risks and uncertainties that could cause our actual results to differ materially from those described in these forward-looking statements. The factors that could cause actual results to differ are discussed in our SEC filings, including our annual report on Form 10-K for the year ended December 31st, 2019, and our quarterly report on Form 10-Q for the quarter ended June 30th, 2020. We undertake no obligation to update or revise any forward-looking statement for any reason. I would now like to introduce today's speakers.
On the call with me today are Dr. Paul Bolno, President and CEO of Wave Life Sciences, who will begin the presentation this morning with Wave's vision and strategy for becoming a fully integrated genetic sciences company. We also have Wave's Chief Technology Officer, Dr. Chandra Vargeese, who will present an update on our PRISM platform, and Dr. Kenneth Rhodes, Wave's Senior Vice President, Therapeutics Discovery, who will discuss our neurology pipeline and C9orf72 program. Following the presentations, we will open up the call for Q&A. I'd now like to turn the call over to Paul Bolno. Paul?
Thanks, Kate. Good morning, thank you for joining us today for our 2020 Analyst and Investor Research Webcast. I'm truly excited about the updates we have to share with you today, as they reflect years of learnings from an evolution of our platform, as well as the hard work and innovation of everyone at Wave and our research collaborators. Throughout this dynamic period, our vision has remained clear, constant, and compelling. Today, I'm proud to say, we have taken significant steps forward towards the ability to develop effective treatments for patients diagnosed with genetically defined diseases. At Wave Life Sciences, we're building a fully integrated genetic medicines company to address the enormous unmet medical need and burden caused by mutations in the genome. Today, there are more than 6,000 genetically defined diseases, the global prevalence of all monogenic disorders at birth is approximately one in 100.
Across the globe, we see dramatic increases in genetic testing and a growing understanding and definition of diseases at the molecular level. We built Wave to leverage these trends and alter the course of diseases that have proven to be intractable and beyond the reach of existing medicines. As a patient-focused, research-driven company, our sustained investment in our platform allows us to advance and deliver on our mission, and we have made great progress in the evolution of our unique RNA-focused platform. Our ability to control the stereochemistry of oligonucleotides and rationally design single drugs serves as a unique foundation to derive insights from chemistry and apply them to biology, resulting in the exciting platform and program data we will share today.
The large body of data we have generated over the last eight years across sequences, chemistries, modalities, tissues, and cells has allowed us to leverage machine learning to further refine and accelerate our ability to rationally design potential medicines. We have remained focused on intervening at the RNA level, where we have the potential to address diseases that are difficult to treat with small molecules or biologics, where we retain the ability to titrate dose, and where we avoid permanent off-target genetic changes and other challenges associated with DNA editing or gene therapy approaches. To accomplish such an important mission, there are four key goals we set out to achieve as we build an evolved PRISM, our proprietary discovery and drug development platform. We needed the ability to address different types of targets and not be limited to a single modality.
A significant advantage of our platform is that we can target RNA through several mechanisms, including silencing, such as RNase H-mediated degradation or AGO2-mediated RNAi, splicing, and ADAR editing. It is because of our focus and continuous investment in understanding PRISM that we were able to reveal and unlock the ADAR editing modality, which has the potential for wide-ranging applications and is applicable across nearly all tissue types. Having the ability to edit RNA significantly expands our target universe, and we have been motivated by the enthusiasm of our ADAR editing capability from a diverse breadth of stakeholders. Next, we needed the ability to optimize the pharmacologic profile of therapeutic oligonucleotides. This morning, Chandra will focus on our ability to optimize potency, exposure, and durability, and will walk you through a set of preclinical data that demonstrates the evolution of our chemistry engine.
Following that, Ken will provide deeper insights as to how we are employing these new chemistries and modalities to build a transformative neurology franchise, as well as the latest data from our promising C9orf72 clinical candidate for the treatment of amyotrophic lateral sclerosis and frontotemporal dementia. Thirdly, the advances we have made to our platform enabled successful target engagement across different tissues. Within neurology specifically, we have demonstrated broad distribution to and target engagement in key cell types within the central nervous system. Our PRISM-derived compounds can access RNA in both the nucleus and cytoplasm without the need for a delivery vehicle. Lastly, we believe scalable and cost-effective manufacturing of nucleic acid technologies is critical. Unlike other technologies, oligonucleotides have the advantage of well-established manufacturing processes and validated test methods based on decades of improvements.
We continue to invest in process development enhancements and have established a GMP manufacturing capacity that is scalable and ensures we have sufficient supply to advance our platform and all of our programs. We have invested significant capital in developing our platform over the past eight years to address all of these goals. Now more than ever, I believe we are in an exciting position with our pipeline, our technology, and our team to deliver transformative results. How do we put Wave's platform in the context of others? Oligonucleotides have a long history with the original PS chemistry modifications used to stabilize the backbone dating back to the 1970s, and there have been more than 30 years of innovations and learnings since the traditional MOE gapmer chemistry was introduced. While other backbone modifications have been developed along the way, their utility has been limited.
With PRISM, we have leveraged those learnings while simultaneously charting new territory with our unique platform innovations. Core to the value of our platform is our ability to design and develop stereopure oligonucleotides as compared to stereorandom mixture-based ones being advanced by others. We have previously discussed, shared, and published the preclinical work in support of our stereopure approach, including at our October 2019 research day. With this focus on stereochemical control, we intend to be the first to fully characterize and investigate the structure-activity relationship of all RNA therapeutics in our pipeline, as has become standard with small molecule and antibody development. We have recently seen others follow suit in this approach. Based on the exciting data we will share today, we remain committed to using stereochemistry as a foundation to elucidate structure-activity relationships and develop precise and rationally designed medicines that leverage the full potential of RNA therapeutics.
We continue to push the boundaries of nucleic acid chemistry, including the use of a new backbone chemical modification in our oligonucleotide design. Controlling stereochemistry allows us to better understand structure-activity relationships relevant to chemistries and different sequences, and I'm excited to have Chandra share data on the benefits of our novel backbone chemistry shortly. In summary, our platform is more than just stereochemistry or one single chemical modification on its own. Through PRISM, we identify, aggregate, leverage, and deploy pharmacological insights with a deep understanding of the interplay among sequence, chemistry, and stereochemistry. Importantly, we have a strong and extensive intellectual property position relating to stereopure oligonucleotides and our novel backbone chemistry modifications. With each new target we learn. These learnings feed into PRISM and are implemented into new programs.
This is a continuous cycle that provides insight into the relationship between sequence, chemistry, and stereochemistry, and how to optimize compounds accordingly. As we showed last year, this has significantly improved the hit rates from our screens, starting with 10%-15% hit rates with our stereorandom screens. Today, we are reaching hit rates of up to 80%, far exceeding industry standards. Additionally, we've been able to open up new sequence space that has been ignored or overlooked, allowing Wave to pursue new potential target sites and accelerate our discovery pipeline. While the opportunities for our technology are vast, we are focused on neurology, where there is a very large and growing number of neurodegenerative and neurodevelopmental diseases with high unmet need. As others have just recently begun to recognize the opportunity in this space, our years of investment have positioned us well to succeed in this area.
We have been able to achieve broad anatomical distribution with our PRISM-designed compounds in the CNS and demonstrated productive target engagement across multiple CNS cell types with multiple modalities. We have also built deep in-house neurology expertise across all functional areas. In CNS, our partner, Takeda, has an option to opt in to any of our Category 1 programs, which include our allele selective HD programs, our C9 program, and our SCA3 program. For the HD programs, this allows Takeda to review proof of mechanism clinical data from our promising SNP3 program, in addition to the results from the ongoing PRECISION-HD clinical trials. Within the Category 1 programs, there are potential milestones that would offset our development expenses. We are halfway through our four-year exclusivity period with Takeda on our Category 2 CNS programs. We are collaborating with Takeda on up to six preclinical targets.
We receive annual committed research support payments for at least four years, with additional funding for ongoing programs committed for a period thereafter. We are eligible to receive more than $1 billion in pre-commercial milestones and royalties for these programs. Beyond our collaboration with Takeda, we have significant growth opportunities using our PRISM toolkit to discover new targets and expand our wholly-owned neurology pipeline. Most recently, we are particularly excited about targets that can be unlocked with our ADAR editing modality. Strategically, we believe that our focus on and capabilities in neurology will enable us to fulfill our vision and achieve the goal of building a fully integrated genetic medicines company. Ken will share more later as to how we are employing new chemistries and modalities to build a transformative neurology franchise later in the presentation.
In developing our platform, we have and will continue to identify opportunities outside of neurology. As such, we are exploring several ways to leverage our platform discovery research and build out areas of potential new biology through collaborations, partnerships, and licensing agreements. While our focus is neurology, we have made strategic decisions to ensure that our innovative chemistry capability is available to external academic, advocacy, and industry partners. The potential of PRISM is vast and the unmet medical need is enormous. Our ultimate goal is to ensure that we maximize the value of PRISM for our shareholders as well as patients and the advancement of science.
As a prime example, we expect to announce our first ADAR editing program in a hepatic indication later this year, pushing the boundaries of what currently is believed to be possible, and we know this technology could be applicable to other therapeutic areas as well. Turning to our current pipeline, as I have just touched on, our pipeline is focused on neurology and is led by our first-in-class allele selective Huntington's disease, or HD programs, including our SNP1 and SNP2 programs, which are currently in phase Ib/IIa clinical development, where our clinical studies will not be part of today's discussion. As we reported during our Q2 earnings call on August 10th, we expect to report data from both the PRECISION-HD1 and PRECISION-HD2 studies, as well as data from both open label extension studies in the first quarter of 2021.
Importantly, we take the learnings from one paid program and apply them to the next. A key example of this is our third allele selective candidate for HD, SNP3, which we are introducing today as WVE-003. WVE-003 incorporates our new backbone chemistry in the candidate design, as well as learnings from in vivo target engagement studies that were not possible with our SNP1 and SNP2 programs. There have also been clinical learnings from our PRECISION-HD1 and PRECISION-HD2 studies incorporated into our SNP3 program, including methods for patient identification. We expect to submit a CTA for WVE-003 in the fourth quarter of this year. Our pipeline also includes our C9orf72 program for amyotrophic lateral sclerosis and frontotemporal dementia, and I am pleased to introduce our C9 candidate as WVE-004. We expect to submit a clinical trial application for WVE-004 in the fourth quarter, expanding our clinical neurology portfolio beyond Huntington's disease.
All of us at Wave are excited to bring this candidate forward to address these two devastating neurologic disorders. Ken will be discussing more about WVE-004 today and sharing new preclinical data. On slide 13, you will notice that our preclinical and discovery programs are all stereopure and our novel backbone chemistry, or PN, is incorporated or being explored in these programs. Chandra will describe PN chemistry in a few moments. Looking to the future, we are driven and motivated by the opportunity to realize the value of our clinical and preclinical programs, as well as the innovations coming off our PRISM platform. We expect to have four global clinical neurology programs next year with multiple data readouts by 2022, and we are well positioned to deliver multiple clinical trial applications over the next three years.
We are leveraging our platform to bring new neurology targets, including editing targets, to the clinic, and we have the potential to realize further value through new collaborations. All of these exciting programs and assets have been derived from continuous learnings from our PRISM platform and our ability to isolate single isomers for rational drug design. Of course, behind these programs and innovations is an extremely talented and dedicated team at Wave. With that, I'd like to turn the call over to Chandra Vargeese, Chief Technology Officer, to shed more light on our recent platform evolution and new chemistry advancements. Chandra?
Thanks, Paul. Good morning to everyone on the webcast, and thank you for joining. As someone who has been working in the oligonucleotide field for more than 30 years, I'm proud and excited by the data that we will share this morning. As many of you know, naturally occurring nucleic acids, both RNA and DNA, are not suitable for use as therapeutics. Multiple features of the nucleic acids are amenable to chemical modifications. These features sequence chemistry of the sugar and backbone and stereochemistry of the backbone form the foundation of PRISM, our discovery and development platform. Our PRISM, we have got an opportunity to investigate the relationship among these features with a depth that has not been possible with any other platform.
We are uniquely poised to unlock the value of backbone stereochemistry and to understand its interaction with other features of the molecule, including sequence changes, and chemical modifications. We talked with you before about how our chemistry advances allow us to control the stereochemistry of chiral backbone modifications exemplified by phosphorothioate or PS modifications. At Wave, our initial investigations into the impact of backbone chemistry and stereochemistry of the oligo pharmacology focused on widely used PS and PSPO backbone chemistry. Today, we are excited to share the expansion of our repertoire of backbone chemistries and modifications and their impact on oligonucleotide pharmacology with the introduction of PN backbone chemistry. With PN modification, a nitrogen atom replaces a non-bridging oxygen atom.
We'll focus on one of these new PN modifications, one containing phosphoryl guanidine, and show how judicious use of this backbone chemistry can profoundly impact the properties of our stereopure oligos. Like the PS modification, PN modifications are chiral. We have developed the building blocks and synthetic capabilities to control the chirality of this backbone linkage. As you can see in the center of the slide, Sp and Rp stereoisomers are PS modifications, which equate to the right-hand and the left-hand positions and are indicated by blue and red carets. You can see on the bottom right of the slide, we represent Sp and Rp chiral linkages of PN modifications with the blue and red brackets, so they are readily distinguished from our stereopure PS modifications, as well as PO modifications that may be included on the mixed backbone.
Unlike PS modifications, PN modifications are neutral, meaning that the negative charge of the oligonucleotide is reduced with every PN modification added to the backbone. Essentially, PN modifications break up the charge of the backbone. The introduction of PN modifications onto the oligo backbone retains complementary base pairing and specificity. Today, we'll demonstrate that rational application of PN modification affects oligonucleotide activity across modalities, including silencing, splicing, and editing. With each modality, we will show you that incorporation of PN backbone chemistry modifications into PRISM is generally improving the pharmacological properties of our oligos by highlighting examples where it improves the potency, tissue exposure, and durability of stereopure oligos. This is the framework I'll walk through on the upcoming slide. As we touch on each data set, I'll refer to the mixed backbones of oligonucleotides that contain PN modifications as PN chemistry.
To illustrate the impact of PN on potency of a silencing modality, I'll walk you through a data set from our screens for identifying RNAi targeting sequences in iCell Neurons in vitro using free uptake conditions. This screen was initially performed with stereopure molecules with PS PO backbone modifications. The potency of the oligos are rank ordered from left to right. I'm going to show you what this head-to-head comparison looks like with the same molecule, same sequence, and same 2' chemistry, with the addition of PN chemistry at various backbone lengths. We repeated the screen with the same molecule where we introduced just a few selectively placed PN linkages, as you can see in navy. The sequences and other chemical modifications on these molecules are unchanged from the molecules with PS PO modification, as shown in teal.
The introduction of a few PN linkages significantly increases the potency of vast majority of stereopure PS PO molecules, with approximately 80% of them yielding at least 75% knockdown. We are very excited by results such as these, which enable us to target sequence space which would otherwise be inaccessible and ensure that we are not restricted by regions in the target transcript. Now we are moving to in vivo incorporation of PN chemistry. In vivo incorporation of PN chemistry is having a more significant impact on our RNase H molecule. We are looking at data from mice evaluated 10 weeks after a single dose. By incorporating just a few linkages, we see persistent transcript knockdown by 80%-90% throughout the central nervous system, including spinal cord, superficial brain regions as the cortex, and deep brain regions as the striatum.
If you compare the persistence of knockdown and relative activities across tissues of CNS, these data illustrate the profound impact of PN chemistry can have on durability and tissue exposure. We have observed similarly profound durability benefits in second experiment, which uses the exact same two molecules in a different tissue type. In this experiment, we evaluated nine months after single intravitreal dosing in the eye, and knockdown at the 50% threshold still persists. We expect the durability and tissue exposure benefits from PN chemistry illustrated on these two slides to open up new indications and target space for neurology pipeline. Turning to a second modality, splicing. Some of our initial work with the PN modification has been explored with exon skipping as a part of our earlier work in muscle.
In fact, the Exon 53 program we had been advancing last year is the first Wave program to introduce PN modification. Today, I'll share several new data sets comparing the impact of few stereopure PN modifications on the backbone of the compounds with identical sequences and 2' chemistry modification, as shown by the two structures on the right-hand side of the slide. These are both new compounds that we have never shared before. This is the first time we are sharing data using a stereopure PN modification on an Exon 23 compound. Similar to the plot I showed previously for RNase H modalities , this plot shows PSPO molecules depicted by teal dots, rank ordered from left to right based on their potency in exon-skipping assays in myoblasts. Keep in mind that with exon-skipping, we are restoring expression, more potent molecules in this graph are shifted upwards.
As you can see by the navy dots, judicious and rational application of PN chemistry to otherwise identical molecules causes an overall upward shift in activity, representing a substantial potency gain for the most part. To highlight the impact of PN chemistry on exon skipping, we turn to DMD Exon 23 as an example. The graph on the left shows exon-skipping data for compounds that differ only by the inclusion of a few PN linkages. At low concentrations, the PN-containing oligos are about 10-fold more potent than our stereopure competitor. On the right, we have evaluated the relative uptake of these molecules in cultured myoblasts. We detect two-three fold more PN-containing molecules in both cytoplasm and in the nucleus, compared to the PSPO compounds, and this is statistically significant.
Now, turning to Exon 23 molecules, I highlight the impact of stereochemistry in turning to DMD Exon 23 as an example. The graph on the left shows exon-skipping data for compounds that differ only by the inclusion of few PN linkages. Now the improved nuclear uptake will be driving part of the potency benefit observed with PN chemistry as exon-skipping oligos act on pre-mRNA in the nucleus. To determine whether exon-skipping improvements due to PN modifications observed in vitro translate in vivo, we turn into mouse models for DMD with a devastating phenotype called the double knockout mice, or DKO mice. Unlike the mdx model, which only has a mutation that eliminates dystrophin expression, the DKO model has a utrophin deletion, which eliminates the compensatory activity of utrophin in mice.
Because of their extreme phenotype, DKO mice set a very high bar for evaluating activity in preclinical models, and thus they're challenging to work with. This work was performed in collaboration with Professor Matthew Wood at University of Oxford. In this slide, we show a survival curve that illustrates the natural lifespan for these mice in orange, with median lifespan of approximately seven weeks. For context, mdx untreated control mice live a normal lifespan. Treatment with stereopure molecules with PSPO backbone modification extends the median survival of these mice to approximately 12 weeks, as shown by the light blue curve. Treatment with the PN-containing molecule provided a profound survival benefit to these animals, extending median lifespan to at least 37 weeks, as shown by the navy line, when the experiment reached completion and was terminated to further evaluate tissues from these animals.
We are now repeating these experiments with PN-containing molecules with a biweekly 75 mg/kg dosing regimen, which is a 75% decrease in total dose compared to the initial study. Although this experiment is still ongoing, these mice are now more than 29 weeks old, and they still appear very healthy. We were surprised and excited by the survival results we just showed, and thus elected to do more testing in these animals treated with PN chemistry-containing compounds. As shown by the PBS control group on this slide, DKO mice have a devastating phenotype and typically do not survive long. We evaluated rescue of other phenotypes associated with muscular dystrophy in these animals. Specific force normalizes maximal force produced by the muscle to its cross-sectional area. Specific force in DKO mice, as shown in orange on the left, is significantly reduced compared with wild-type controls, as shown in black.
Mice treated with PN-containing molecules perform like wild-type mice in this analysis, shown by the navy line. Moving to the chart on the right, eccentric contraction force measures force over sequential contractions, as contractions induced injury in dystrophic muscles can decrease muscle force over time. Once again, mice treated with PN-containing molecules performed like wild-type mice in this analysis. One last example on exon skipping, we conducted a separate six-week study designed to assess the PK/PD relationship for PN chemistry as compared to those with PS-PO modifications . We found that the PN-containing compound accumulated to higher levels in all muscle types compared to the PS-PO compound . The PN chemistry also led to more exon skipping and more dystrophin restoration in all muscles, but especially in the heart and diaphragm.
Thus, in yet another example, the introduction of just a few PN linkages with no delivery vehicle and no conjugates significantly improves the PK/PD profiles for stereopure compounds. The significant differences we see in difficult-to-reach muscles like the heart and diaphragm likely explains the profound survival benefit observed in these DKO mice. In summary, these data are very exciting and important to understanding the benefits of PN chemistry in the context of splicing. Now, our third and newest modality, ADAR editing, is one that I'm particularly excited to discuss with you today. We have only recently opened this modality as a direct result of the advances we have made with our PRISM platform over the past eight years, including chiral control and PN chemistry modifications.
In our ADAR editing approach to RNA editing, we employ short, chemically modified oligonucleotides to recruit endogenous RNA editing enzymes called ADAR to change a specific adenosine to inosine in the target transcript, which the cells read as guanosine. The result is effectively a change of an A to G in RNA. ADAR editing is a common post-transcriptional RNA modification that generates transcriptomic diversity, and the ADAR enzyme is ubiquitously expressed across tissues. Beyond offering advantages over gene editing, this technology is unique within RNA editing. We are at the forefront of developing this capability by leveraging endogenous ADAR proteins, which avoids the risk of immunogenicity from exogenous proteins and the potential related off-target effects. Our technology does not require a delivery vehicle such as AAV, and our oligonucleotides typically have 30 bases or fewer.
Importantly, our ability to control the chirality of the backbone enables us to maximize the endogenous ADAR activity. In our initial therapeutic investigations, we are using GalNAc conjugated oligonucleotides for hepatic targets. As we continue to build our RNA editing capabilities, we expect this technology could be used across various therapeutic indications. Nearly half of the human pathogenic SNPs are G to A mutations. The unique capability of ADAR to correct these mutations creates significant opportunities for us to potentially treat a broad spectrum of human diseases, including diseases that currently have no treatments or only suboptimal treatments. The application of PRISM to RNA editing opens the door to a whole range of therapeutic applications. ADAR can be used in multiple ways to restore protein function, to modify protein functions, and to increase protein expressions.
Over the past eight years, we have made significant investments in our PRISM platform and have evaluated more than 1,000 ADAR editing oligonucleotides to produce insights into the relationship between an oligonucleotide structure and its ability to elicit ADAR editing activity. We have leveraged these learnings to accelerate movement into new modalities. Here we show the activity of beta-actin editing stereopure oligonucleotides with and without PN linkages and compared to matched stereorandom control oligonucleotides shown in black in primary human hepatocytes. These oligonucleotides are GalNAc conjugated to increase the uptake in hepatocytes. As you can see here, the addition of PN chemistry to the backbone substantially improves both potency and editing efficiency. As we have previously described, we have achieved efficient RNA editing in vitro with our oligonucleotides across a wide variety of cell lines, including non-human primate and human primary hepatocytes.
As shown here, we have observed potent dose-dependent RNA editing with three chemically distinct stereopure oligonucleotides via GalNAc-mediated uptake. Our next task was to determine whether these results translated to an in vivo system, which they did. For this study, we dosed non-human primates subcutaneously once a day for five days with the same three chemically distinct RNA editing molecules. We took liver biopsy samples at baseline and two days after the last dose and evaluated editing of the transcript. As previously shown, we detected up to 50% editing as compared to baseline of zero two days after the last dose. Remarkably, this effect is durable. We continue to see significant editing 45 days after the last dose, as shown in the chart on the left. PK data on the right confirms that a significant amount of oligonucleotide is still detectable in the liver at that time.
Sanger sequencing allows ADAR to be quantified from peak heights of sequence traces. As you can see on the slide, these plots show zero editing at baseline and durable editing at the target site 45 days after the last dose. Next, to evaluate specificity of ADAR editing oligonucleotides, we performed RNA-seq in primary human hepatocytes. On the left, you can see total sequence coverage across the NHP beta-actin transcript for the mock-treated group shown on the top and the oligo-treated samples shown on the bottom. The percentage of unedited T and edited C reads are indicated for each group. As you can see, the editing is only detected at the targeted sequence in the actin transcript. To assess off-target editing for the whole transcriptome, we applied a mutation-calling software to call edit sites. From this analysis, we observed nominal off-target editing across the transcriptome.
Sites where potential off-target editing occurred mapped predominantly to non-coding regions of the transcriptome and had either low read coverage in the analysis or occurred at low percentages of less than 10%, indicating that these are relatively rare events. In both analyses shown on the left and right, we find a high percentage of editing that is specific for the target site in the actin transcript. We have also performed off-target analysis for our non-human primate experiments and observed no overlap in vivo of the low confidence off targets seen in our in vitro samples, which further supports the specificity of ADAR editing. The next question we sought to answer was if we could achieve ADAR editing without GalNAc conjugation. As a step towards expanding application of our RNA editing modality to the central nervous system, we have assessed editing in vitro in both neurons and astrocytes.
Our PN-containing stereopure molecules elicit efficient editing in both iCell neurons and iCell astrocytes, with EC50s for astrocytes reaching the 200 nanomolar range in vitro. Keep in mind, these potencies are obtained with chemical modifications to the oligonucleotides alone under free uptake conditions. There is no delivery vector and no conjugates used in these experiments. I'm excited to share with you preliminary data from an ongoing experiment investigating the suitability of RNA editing modality for CNS indications. We have now evaluated editing activity with PN-containing stereopure oligos after a single injection into the CNS of a proprietary humanized mouse model. We see approximately 20% editing activity across CNS tissue, with 50% or more editing activity in several of them.
We're very excited about these results, as they are preliminary findings with editing compounds that target a transcript that is challenging to edit efficiently, and we are still detecting good editing efficiency throughout the CNS. Further optimization work of our stereopure editing compounds is underway, and we look forward to sharing additional in vivo results in CNS very soon. Today, we have shown you that the judicious and rational use of PN modification leads to significant changes in the pharmacology of oligos across modalities. While PN chemistry is important and exciting, it's our PRISM platform that has allowed us to unlock the value of this novel modification. When we created PRISM, we began with the bold idea that backbone chemistry and stereochemistry matter.
It's only because we looked beyond the 2' position of ribose and considered the entirety of chemical modification available to us that we have recognized the value of PN chemistry. With PN chemistry and other PRISM innovations, we have gone beyond silencing and splicing and unlocked ADAR editing with endogenous ADAR enzymes. We have been able to move swiftly with our discovery work, and we continue to expect to announce our first ADAR editing program in a hepatic indication later this year. We are working to quickly expand the repertoire of tissues where we can apply ADAR editing, including our focus in neurology. With that, I'll turn the call over to Ken Rhodes to discuss our growth opportunities in neurology specifically. Ken?
Thanks, Chandra. Good morning, everyone. The data you have just seen underscore the many reasons why I'm excited to have joined the Wave team and have the opportunity to put this elegant and expanding platform to work in developing new therapeutics to address neurologic diseases. We're in an incredible period in neurology drug discovery. Key genetic drivers and risk factors for many neurologic diseases have been identified, enabling to leverage our PRISM platform to deliver medicines that directly target underlying disease mechanisms. With ADAR editing, we have a powerful new modality that can be used to advance novel therapies, and we expect ADAR to become an important component of our neurology strategy moving forward. Our growing neurology pipeline shapes up as follows.
As Paul described, in the clinic, we have our allele selective SNP1 and SNP2 programs for Huntington's disease, with data from both ongoing trials as well as our open label extension studies expected in the first quarter of 2021. Next, our allele selective SNP3 program, also targeting Huntington's disease, is expected to begin clinical development with a CTA submission in the fourth quarter of this year. Our variant selective C9orf72 program is also expected to begin clinical development with a CTA submission in the fourth quarter of this year. As Paul shared at the outset of this call, our SNP3 and C9orf72 programs incorporate our novel PN chemistry backbone modification designed to offer increased potency and duration of action. Behind those programs, our discovery and preclinical pipeline includes multiple programs partnered with Takeda targeting diseases of the central nervous system.
Among these programs, we have incorporated or are exploring the incorporation of PN backbone chemistry modifications to our lead molecules. For the next portion of this presentation, I'll be speaking about our C9orf72, or C9 program, and WVE-004, our C9 candidate. First, a bit of background on C9. C9orf72 hexanucleotide repeat expansions are the strongest known genetic driver for the more common non-inherited or sporadic and less common inherited forms of ALS and FTD. ALS is a fatal neuromuscular disease resulting from the degeneration of motor neurons in the brain and spinal cord. FTD is the second most common form of dementia after Alzheimer's disease and results from neurodegeneration in the frontal and anterior temporal lobes of the brain. Both diseases represent areas of high unmet need, despite there being two approved therapies for ALS. There are no approved therapies or disease-modifying therapies for FTD.
There are approximately 2,000 patients living in the U.S. with ALS that carry a C9 repeat expansion and approximately 10,000 patients living in the U.S. with FTD that carry a C9 repeat expansion. The C9 gene provides instructions for making C9 protein, which appears to play a key role in neurons and immune cells, where it functions in biological processes related to endosome trafficking, protein homeostasis, and immune cell activation. Hexanucleotide repeat expansions in the C9 gene lead to reduced expression of C9 protein, accumulation of repeat transcripts and RNA-binding proteins in the form of nuclear RNA foci, and aberrant expression of neurotoxic dipeptide repeat proteins or DPRs. The importance of wild type C9 protein has been highlighted with the creation of mouse models that lack the mouse ortholog of C9orf72.
These mice demonstrate an enhanced immune response and an enlarged spleen, indicating that the C9 protein plays a role in immune cell activation. Moreover, when expression of C9 protein is reduced, neurons become more susceptible to toxicity caused by the dipeptide repeat proteins produced from the repeat-containing C9 transcripts. The hexanucleotide repeats in C9orf72 likely contribute to ALS and FTD through multiple mechanisms that individually or collectively contribute to disease. First is the reduced levels of C9 protein caused by haploinsufficiency of the repeat-containing C9 allele. As mentioned previously, in preclinical models, loss of the normal C9 protein renders neurons more susceptible to DPR toxicity, making it imperative that any potential therapy preserves C9 protein. Second is the accumulation of RNA transcripts containing the hexanucleotide repeats.
These repeat-containing transcripts accumulate in cell nuclei, leading to an accumulation of RNA-binding proteins forming large, abnormal RNA foci, which can disrupt expression and processing of other genes. Last, the repeat-containing mRNA transcripts can be translated through an atypical mechanism called RAN translation into aggregation-prone polypeptides containing long dipeptide repeats, the DPR proteins. The DPRs can trigger cellular toxicity through a variety of downstream mechanisms. The goal of our C9 program is to reduce the accumulation of repeat-containing transcripts, thereby reducing RNA foci and production of DPRs while preserving expression of the normal C9orf72 protein. Our clinical candidate is designed to selectively silence the pre-mRNA repeat-containing variants that ultimately lead to DPRs and RNA foci. These variants are commonly referred to as V1 and V3. Importantly, our candidate does not target the V2 transcript, which is the main contributor to C9 protein expression.
This selectivity is achieved through a targeting strategy that directs our therapeutic candidate to a sequence that is only accessible in V1 and V3 transcripts. As you will see in the upcoming slides, our candidate provides potent, selective, and durable knockdown of repeat-containing C9 transcripts and the DPRs in preclinical model systems while preserving expression of the normal C9orf72 protein. WVE-004 is designed with our PN chemistry backbone modification and was optimized for potency and preferential activity against repeat-containing V1 and V3 transcripts. In this experiment, we show that our candidate potently and selectively reduces V3 transcripts in induced pluripotent stem cell-derived motor neurons made from a patient carrying a C9orf72 repeat expansion. As shown in the figure on the left side of this slide, the IC50 of our candidate under free uptake conditions is approximately 200 nanomolar.
On the right side of this slide, our data comparing our candidate with a non-targeting control ASO showing the selectivity of our candidate for the repeat-containing V3 transcripts. Building upon the potency observed in vitro, we next explored dose-response relationships for WVE-004 in vivo using a mouse BAC transgenic model engineered to overexpress the human C9orf72 repeat-containing sequence. In this study, we gave ICV doses of our therapeutic candidate at increasing dose levels to the mouse. One dose was given on day zero, and a second dose was given on day seven. Six weeks after dosing, we assessed the levels of V3 mRNA and the poly-GP DPR polypeptide. We also assessed tissue concentrations of our candidate. As you can see, administration of WVE-004 produced a dose and concentration-dependent decrease in V3 transcripts and the poly-GP DPR in spinal cord tissue.
In this same study, qualitatively similar dose-dependent knockdown of V3 transcripts and the poly-GP DPR protein were observed in mouse cortex. One of the important features of our PN-containing molecules is they show potent knockdown of target sequences and a long duration of action in vivo. This slide shows the results of an in vivo study in the BAC transgenic model, where we gave a single ICV dose of our therapeutic candidate on day zero and a second dose on day seven. Eight weeks later, we assessed levels of V3 transcripts, poly-GP DPR protein, and levels of C9 protein as a marker for the specificity of our targeting strategy. In spinal cord, we saw potent knockdown of V3 transcripts, reducing them by approximately 80%, and also dramatic reduction of the poly-GP DPR by over 90%. We also observed complete preservation of C9orf72 protein expression.
These effects were sustained out to eight weeks, the last time point of this study. As we previously presented, in this study, we also saw a potent and durable knockdown of V3 transcripts and poly-GP, as well as preservation of C9 protein expression in the cerebral cortex. Overall, this pattern of activity confirmed our variant selective targeting strategy and clearly demonstrated that our candidate has potent and sustained activity in brain regions associated with ALS and FTD. At the conclusion of this eight-week study, we used an in situ hybridization histochemistry method called ViewRNA to image the cellular and subcellular distribution of our therapeutic candidate in the CNS. To remind you of the experiment, BAC transgenic mice received an ICV injection of WVE-004 or PBS on day zero and day seven. Eight weeks later, brains were removed and sectioned and processed to visualize the distribution of WVE-004.
The presence of our candidate is revealed as red punctate staining in the cytoplasm and nucleus of animals treated with the clinical candidate, but not in animals treated with PBS. As shown here, WVE-004 penetrates into motor neurons in the anterior horn of the spinal cord and neurons in the deep layers of the neocortex. The clear signal for our oligonucleotide in the nucleus of labeled cells, as marked by the blue arrowheads, indicates that the molecule has access to the cellular compartment where C9orf72 repeat-containing pre-mRNA transcripts are located. Together with the knockdown of V3 transcripts and DPRs, the ViewRNA data are very encouraging as they clearly demonstrate our clinical candidate reaches therapeutically relevant target neurons in spinal cord and cortex. WVE-004 also clearly evokes potent and durable pharmacodynamic responses in these regions.
As in the examples that Chandra shared during her presentation, adding PN chemistry to the oligonucleotide backbones in our C9 program improved potency in reducing repeat-containing transcripts in vitro. PN chemistry also improved potency in vivo. When compared to an identical sequence without PN chemistry, shown here in the light blue circles. The addition of the PN modification represented by the dark blue circles resulted in greater knockdown of C9 repeat-containing transcripts at all oligonucleotide tissue concentrations. Encouraged by these exciting in vivo results, we initiated a follow-on study designed to further explore the duration of action of our C9 candidate in transgenic mice. In this study, we examine the effects of single ICV doses of our candidate, given on day zero and day seven on V3 transcripts and poly-GP out to 24 weeks, or roughly six months following the initial doses.
As shown here, we observed a remarkable 60%-80% knockdown of V3 transcripts in spinal cord and a 40%-50% knockdown of repeat-containing transcripts in cortex six months after dosing. Moreover, two doses of WVE-004 on day zero and day seven of the study reproduced a greater than 90% knockdown of the poly-GP DPR protein in spinal cord and an 80% or greater knockdown of the poly-GP DPR in cortex. As marked by the orange boxes, these dramatic effects persisted for at least six months following the initial dose. These impressive results are particularly exciting as we consider dosing at intervals in the clinic. I'll now provide a brief update on our clinical development plans for WVE-004. In our proof-of-concept clinical study, we plan to include both ALS and FTD patients with the intention to advance development in both indications.
Specifically, we expect to enroll patients with confirmed diagnosis of ALS or FTD and consistent with our precision medicine approach, a documented hexanucleotide expansion of the C9orf72 gene. Single and multiple ascending doses will be explored along with safety and tolerability. As in our preclinical in vivo studies, we have the ability to sensitively measure the poly-GP biomarker in human CSF, which will afford us the opportunity to assess signals of target engagement in the clinic. We also intend to look at neurofilament light chain as well as other biomarkers. We expect to be able to share more details on the trial design once these are agreed upon with key stakeholders, including regulatory authorities. As mentioned earlier, we are on track to submit a CTA for this program in the fourth quarter of this year.
Looking ahead, our PRISM platform affords a uniquely diverse toolkit with the potential to address a wide range of neurological disorders. Part of my focus at Wave will be to identify additional genetically validated targets and mechanisms that we will pursue in our next generation of therapeutics discovery programs beyond those that are part of our ongoing collaboration with Takeda. As Chandra shared earlier, we are generating exciting proof-of-concept data for ADAR editing in the CNS, presenting us with a new therapeutic approach that will allow us to explore an array of exciting opportunities in neurology. While we are not disclosing specific targets or programs today, we are incredibly excited about the future of our neurology portfolio, and I encourage you to watch this space. With that, I'll turn the call back over to Paul for closing remarks. Paul?
Thanks, Ken, and thank you, Chandra, for giving us an update on the tremendous progress within our platform. I would like to conclude by re-emphasizing how much we've learned over the past eight years and how those learnings have shaped the platform and discovery and preclinical programs we are bringing forward today. The capabilities of PRISM enable us to unveil the potential of PN chemistry and the impact of adding these modifications to the backbones of our therapeutic candidates. We have unlocked ADAR editing, a new and exciting modality that we are at the forefront of realizing value from. Altogether, these advancements will enable us to deliver a sustainable platform to feed our pipeline of RNA therapeutics and drive value for all of our stakeholders. With that, I'd like to turn the call over to Q&A. Operator?
Thank you. As a reminder, to ask a question, you will need to press star one on your telephone. To withdraw your question, press the pound key. Please stand by while we compile the Q&A roster. Our first question comes from Joon Lee with Truist Securities. Your line is now open.
Hi, guys.
Hey, Joon.
Thank you so much for the presentation. Very exciting. Thanks for taking my questions. I had one question for each program, the PN, ADAR, and C9orf. For the PN, I'm just curious if you have any immunogenicity data regarding the new backbone. Does introducing an unnatural and synthetic backbone cause any immunogenic response? On the ADAR program, I know that ADAR knockouts are embryonic lethal and that they're highly active during embryogenesis. What's the role of ADAR in adults, and how broadly is it expressed to be of therapeutic utility? What would be the consequence of diverting away ADARs from their normal activity to function as editors endogenously? On the last question... Actually, I'll just stop there. I'll just hop back on the queue.
No worries. It's good that we are keeping track of it. The first question as it relates to PN chemistry, and I'll hand a lot of these questions over to Chandra, but just to frame it, the work on chemistry that we've been using on PN, as we mentioned in our presentation, it's been integrated into a number of programs with which have IND-enabling studies or CTA-enabling studies underway to support those submissions and as we said earlier as well, have been incorporated into our Exon 53 program systemically, which we've used, and as we said last year, have been planning to submit a CTA for before [tominersen]. We have an extensive support going forward. Obviously, safety is something that has to be assessed in the clinic.
Chandra, do you have anything you want to update on as it relates to the PN chemistry modification specifically? Then we can take ADAR as a separate subject.
To add to your point, PN chemistry, what we're using is very, we're judiciously placing in a few places, and these are again, useful backbone. The toxicity, to Paul's point, the toxicity and the immunogenicity is all looked at as a whole molecule, with different backbone chemistries. It's not just a pure PN molecule. Just to be clear.
I think to follow up on that point, it's a great one, Chandra, because I think, Joon, this is one of the advantages that I think as we've said from the very beginning in characterizing single drugs, is that we are able to characterize the whole molecule. With the incorporation of the PN modification itself, that modification is also chirally controlled. We're still assessing each molecule, and we do evaluate the immunogenicity of a molecule on it in totality as that medicine. We're able to still do those assessments individually. You wouldn't expect to see that as a unique feature of the PN chemistry itself, but we continue to be able to assess it in the totality of the molecule. Did that answer your PN question? We can shift to the ADAR question.
Yeah. That was very helpful. On the ADAR, I'm just really curious about what it does normally and why and how you would?
Yeah. Well, the first question is probably an immunogenicity question, too, anyway. I want to say that, by using the endogenous system, you don't have the immunogenicity characteristics. There's a number of components that are being explored with others that are putting in a new engineered enzyme. By not having to engineer the enzyme, to Chandra's earlier point during the discussion is, by not having to engineer it, there's not immunogenicity associated with the endogenous enzyme.
Yep, absolutely.
Chandra, your other questions, Joon, I just want to make sure I have it, is on how to engage it away from its, you said, its ordinary function and just being able to utilize it.
Yeah. Just ADAR, what little I know about ADAR is that they're important embryonically, and they're lethal if you don't have it. How active is it in the adults, in adult patients that you hope to achieve a therapeutic effect in? Also, if it is actually broadly expressed, what would be the consequence of hijacking ADAR, thereby diverting them away from their normal function, and what would be the safety consequence of that in your thoughts?
Yeah, just to take some of that on, I think as we approach this, again, safety as any therapeutic is something that gets assessed clinically. I think being able to utilize it is expressed. Obviously, there's different ADAR enzymes that are in different tissues, and the ADAR enzyme we're using has a broad distribution associated with it, which helps us get to a number of cell types that we can utilize. I don't look at it as necessarily hijacking it, but at least using it, and using it for an intended consequence of editing, to date, hasn't shown any detrimental consequences. Obviously, there's a lot more work to be done in terms of its clinical translation.
We're pretty excited by the fact that across species, as Chandra alluded to in this presentation today, both at the non-human primate level of editing in vivo and in a proprietary mouse model where we could assess it, in both circumstances, we've been able to look across the class. It's still transient in the sense that we're not permanently hijacking, and just to use your words, the enzyme. There is this kind of ability to use it, edit it, and that transient feature is great. That's another reason why we've stayed away from kind of using viral vectors and other approaches to use it, and therefore, like any of the therapeutics, we can titrate the oligonucleotide to drive that intended effect. Did that answer?
Yeah, absolutely. What's your intellectual property around this? Obviously, ADAR is endogenous, so it seems like anyone who has the ability to take advantage of endogenous ADAR could maybe potentially go and do AGG edits, which is about 50% of the diseases as you present. How are you differentiated from potential other RNA-editing companies that are out there? I think there are a few, but I'm just curious your thoughts there.
Yeah. I think one of the advantages, our focus has, in all the categories we're going after, is on the medicines. It's on the molecules themselves. You're right, the enzyme itself is endogenous, but because we're not doing something around engineering a new enzyme, but utilizing the endogenous enzyme, you're right, we're able to focus and train our intellectual property, but more importantly, our drug discovery and development efforts on the molecule itself. Our intellectual property is built around how we build the molecules that are themselves able to engage the enzyme and promote editing. In the same way we would do that in engaging RNase H for antisense-mediated silencing, AGO2 for RNAi silencing, splicing, et cetera. We build the IP around how we build molecules.
Great. Thank you very much.
Thank you.
Thank you. Our next question comes from Paul Matteis with Stifel. Your line is now open.
Hey, this is Alex in for Paul. Just a couple questions on the new phosphoramidite backbone chemistry here. I guess, I'm curious if you have any thoughts on kind of why this backbone seems to be better. Does it have to do with charge? Are the molecules getting into cells better? Is it a sort of a geometry thing? Are they more rigid? How is that happening? If you have any thoughts there, that'd be helpful. Also related to that, I'm just curious, like, when you're looking at a sequence comparison between the PSPO and PSPN combos, it doesn't seem like PSPN is always better. I'm curious if you're really confident that the PN is really having that benefit all the time, and how you're thinking about all of the different sequences you could test as you're trying to optimize which sequences to go after. Thanks.
That's great. I'll turn the call over to Chandra. I think we've pretty much shown extensively when we've done rank ordering of compounds, and there's always variability in screening. When you look at the PS to the direct comparator of the addition of PN in both the silencing applications as well as in splicing. Both in down-regulating and up-regulating, we see a direct comparison of what that gets us in terms of benefit in both approaches. I think what's really unique, and I think will be exciting, is Chandra explaining the work that's underway in understanding PN chemistry. This is very much a work in progress. I think we're excited by the data we're generating and excited by what we're continuing to learn, the innovations. Chandra, do you want to share more about your thoughts around PN chemistry?
Yeah, sure. The PN chemistry, adding to Paul's things, this is neutral. What we always was interested in is that when we were using stereo pure PS constructs, we saw these things taken up so rapidly by cells. The next question we asked was, okay, what if we introduce neutral backbone? You break up some of the charges, and then you try to explore more on the chemistry side. When we did that, we saw this uptake was rapidly enhanced, and I showed that in the slide. What we think is that it's a combination of charge, stability, and also, to your point about some of the conformational changes that can actually help us to penetrate to the cells and to travel through the cells.
Again, some of the things we understand very well and some of the things we are still in the exploration mode. We'll be publishing some of the data fairly soon. It's pretty exciting to see the addition of a couple of PN changes the whole profile of the molecule.
Then to Chandra's point, and just to add it is about the concept of rational and drug design. It is about, as Chandra said, the judicious use of where you put that in. As we built our intellectual property estate, both on the modification itself and how you use it, one of the things that had been explored is that the complete use of PN modifications actually yielded suboptimal results. It's not about just creating all PN. I think this is really the value of what we've been able to unlock from the very beginning in the value of what studying single medicines gets us. Anybody who was at Research Day in 2019 can remember Greg and our co-founders reminding everybody that you can't optimize a mixture.
I think this is really the testament to how you create continued optimization in rational drug design as to the benefits of a new modification is about where you put it. I think we're excited about a lot of the work we're doing in terms of seeing this exposure. I think where we are today, and which is exciting, is we see it in multiple in vivo models, whether we're looking at the central nervous system, whether we're looking at muscle, whether we're looking at hepatic, and we're seeing it across multiple modalities, antisense, RNAi, exon skipping, and ADAR editing.
I think as we look at the totality, we're really excited about the movement we made with good in vivo modeling that then lets us help think about dose exposure and ultimately clinical translation, which is where we are today in thinking about a number of clinical and potential clinical programs that we're moving forward in our pipeline.
Great. Thanks so much.
Thank you. Our next question comes from Salim Syed with Mizuho. Your line is now open.
Great. Thanks so much for doing this, guys, and appreciate all the color. Just a few from me, if I can, and hopefully I'll have a question for everybody here. Paul, maybe just strategically, with regards to the PN chemistry, I couldn't help to notice that there was some myoblast data and mouse muscular dystrophy data for the PN portion of the slides. Is there any intention at all to use the PN chemistry to get back into DMD, and then also perhaps apply this to SNP1 and 2 for HD? Second question is on ADAR. Chandra, curious why just starting off with hepatic. What's the backstory there? Because I noticed you mentioned quickly into neurology. So why is hepatic the first indication here?
Is there any link to neuro for that hepatic start, and is that a commercial indication, or is this something where you need it to get into neuro? What does quickly into neurology mean? Lastly, for Ken. Ken, I was curious why, for the exploratory, you're using ALSFRS and not ALSFRS-R, which, if I recall from the September 2019 FDA guidance, specifically calls out the dash R as the perhaps better measure to use from the FDA guidance. Thank you.
All right. I have the list, Salim. We'll start with your Exon 53 question, then we'll move to ADAR hepatic, and then Ken's question around the ALS. As it relates to Exon 53, obviously, today's data and discussion was focused, and I think it's really important on understanding PN in the context of splicing. I appreciate that. There was a combination, first emphasis, and while it was extensive around myoblasts and studying the impact in a really severe phenotypic model, it really gave us the ability to study what happens when PN chemistry and how does it access muscle tissue. These have profound results in a way that was extraordinarily exciting and gives us reason to be excited about the Exon 53 molecule that did include PN chemistry. We are revisiting the 53 data, but we're exploring potential collaborations to advance the program.
There's a thought. We're not going to ignore the data that's driving it, but we're also proceeding in a very cautious way. As it relates to ADAR, and I'll hand it off to Chandra, but I think it's important that when you explore new molecules, one of the questions that we had with ADAR was by using GalNAc, we could target a specific cell type. I think there was an initial approach when you're building the SAR and building the understanding of an individual molecule, to give it a way to assess it in vivo, and in this case, particularly in NHPs. GalNAc obviously leads to hepatic. I think you also asked a question around the commercial target and how we're thinking about it. Absolutely.
We are thinking that if we are developing a potential molecule, that we do think about a substantial indication in a way that also is not just about doing something that one can use doing a different modality, but really a target where we can explain why we would specifically utilize a correction mechanism versus, let's say, a silencing mechanism with GalNAc. That really drove us in terms of, one, the hepatic, but two, what we're thinking about with the hepatic, where it's not just fast-following another approach to silencing, but working on a disease where by correcting gives us a unique insight, unique advantage in that target space. Chandra, I don't know if you have anything you want to add, and then I'll hand it off to Ken to answer the question around ALS.
Yeah. I can add to something, Salim, that expression levels of ADAR is also high in the liver. We also had all the infrastructure to understand about editing using primary hepatocytes. When we were evaluating the platform to show that endogenous ADAR can edit, for us, we found it actually very useful to look at it primarily first in hepatocytes. GalNAc, of course, GalNAc can deliver. If you want something as a proof of concept, it was a very well-suited place for us to try, initially in hepatocytes. Now we got the confirmation, so we can now jump into other tissues. ADAR is ubiquitously expressed in all the tissues, so that's where proof of concept was really our primary focus initially. To Paul's point, we also will announce a target by the end of this quarter or sometime in 2020.
Just to add and follow up, because you also bundled into that question, Salim, I think a CNS question around just ADAR and in the central nervous system. I think, given that the enzyme that we're targeting is also present in those tissues, that lent itself nicely to continue that exploration in a non-GalNAc context. Obviously, the data we have today, excited about not just the in vitro editing in various cell types in the central nervous system, but also within the in vivo data that we just shared, gives us directional confidence that we can get exposure and develop drug. I'll hand off to Ken to give a little bit of context on how he's thinking about that in neurology, but also to continue on to answer your last question that related to the ALS topic.
Yeah. Maybe I'll take the last question first, which is about ALSFRS in our upcoming C9 trials. I think we are using the ALSFRS-R. I think the "-R" must have been left off the slide. I think suffice it to say that our intention is to follow the latest guidance in our clinical development program. For ADAR CNS, I think quickly is a relative term, but there was a fair bit of really interesting work going on with ADAR and CNS targets when I joined Wave a few months ago. As I've become more familiar with the technology, we've started to look more broadly at potential ADAR targets. That process is ongoing but moving very quickly. We hope to be able to talk about specific programs in the very near future.
Just to round out, I think the excitement around what is achievable with ADAR editing opens up unique target space. I think the reason we started in liver, GalNAc was one reason, but not the least of which are a number of really compelling opportunities in that space. I think as we look uniquely about building a genetic medicines toolbox that has the capability of going and expanding across multiple therapeutic and disease areas, I think we've built that capability in-house and are excited to continue to share that data as we progress.
Great. Thanks so much for the call, guys.
Absolutely.
Thank you. Our next question comes from Debjit Chattopadhyay with H.C. Wainwright. Your line is now open.
Hi, guys. Good morning. Thanks for taking the question. This is Aaron on for Debjit. I wanted to ask, do you see the potential of the ADAR editing program primarily in changing pathological individual mutations, which I could see being a challenge in identifying a large addressable market for a largely shared mutation? Is there also opportunities that you're looking at to knock down or even enhance the expression of these long chains?
Yeah, the line was definitely breaking up as you were speaking. If we don't answer your question, let us know. I think you were highlighting that there are a unique number of approaches of using the editing piece, whether it's around correction, inducing stop codons, there's a variety of ways to think about using it in a variety of different categories. I think initially, and again, to kind of distinguish it from silencing applications. I think that's what's unique about our opportunity is we've got great tools to do silencing where we need that in utilizing expression.
I think the idea of using ADAR as an opportunity to correct where there are unique opportunities like we're exploring in liver, where there are areas where downregulation is important and others where upregulation is important, and really viewing it as how do you correct, and correction being a different application than silencing.
Okay, yeah.
I think it'll become more clear as we think, and we're happy to spend more time, and we did earlier in the presentation, laying out this multitude of ways of thinking about that, because I do think there are opportunities around that correction space. As we think about the first target in hepatic, we'll be sharing more around that target that I think will put it in a lot more context is how we're thinking about correction. The target space is pretty vast, and I think our first approaches are ones where it would not be ambiguous why we would choose this approach for that target.
Okay, great. For the C9 program, why is it starting in ex-U.S., and what would you need to begin an active IND?
Well, given that we've not yet announced the final filing, and we're not guiding to geography. I think we have full intention as we think about ALS as a critical disease of patients everywhere. I think we're looking at part of a global study. There's nothing imminently now that would, we'd say, preclude us from being in the U.S. based on anything to think.
Okay, good. All right. Thanks, Paul.
Yeah.
Thank you. Our next question comes from Mani Foroohar with SVB Leerink. Your line is now open.
Hey, guys. Thanks for taking the call. A couple of quick ones, although fewer than the 37 that Joon had. In terms of drug delivery, you talked a little bit last year around the value of backbone chemistry and some sort of machine learning technologies that you guys have when you think about improving cellular delivery. Can you give us a sense of how what you've learned from your experiences with tominersen, the huntingtin interim data, et cetera, how those informed how you think about your delivery tools and how they might be applied to this new technology? Beyond that, obviously, a lot of the expertise that you've built thus far applies here.
Are there additional investments that you expect to be making around development and manufacture infrastructure, specialized expertise you expect to bring in on the human capital side, and how you think about the timing of those investments and build-out as this technology continues to develop?
The great news is when we're talking about enhancing delivery, we're not doing it via the need for building out new conjugates. This isn't about building a new antibody conjugate that's going to require a build-out of antibody manufacturing. The benefit of what we've done today is really a continuation of what we started at the very beginning, which is to build a world-class nucleic acid discovery engine that's capable of taking constant learnings and applying them and seeing where those advantages are. The good news is it all leverages our existing infrastructure, our existing talent and our existing manufacturing competency. Our GMP facility can manufacture the PN molecule.
This is really a testament to the fact that if you remember as we were moving into the latter part of last year, we were prepared to manufacture an Exon 53 molecule. We've already built that manufacturing capability within our existing facility, so there's no additional requirements or investments required to utilize PN chemistry. We've also been utilizing it as we've advanced our C9 program, our SNP3 program. This is not something, again, today that we're saying is going to be forward needing to be built out, but something that we've invested in and have already begun to realize that translational value of. It's interesting because when we say delivery, there's a lot of different contexts that people think about delivery. Oftentimes it's around having this kind of conjugate strategy. When we talk about delivery, another way of thinking about it is accessibility.
How do we see increased accessibility of cells and tissues with the modifications we're imparting? I think that was the learning. When we talk about machine learning, one of the things we've done is we've generated hundreds of thousands of oligos. The idea of being able to make drugs, move those chemistries around, and have those be single medicines. Now the richness of the data sets that we're getting, each time we look at a molecule, we're able to understand where do these molecules need to be placed in order to drive that efficacy and then be able to use that across multiple programs. As we said, we've been incorporating this chemistry into C9, SNP3. It's incorporated into our collaboration with Takeda, so we're getting multiple programs that we're able to assess this with.
The data that we've generated in muscle was profound when we've shifted to the addition of PN chemistry in terms of exposure into muscle. We know that exposure is a key ingredient, hence being able to reduce the doses substantially and being able to look at that exposure level. I think we need to think about it as PNs delivery, just because I think it makes people think of a vehicle to deliver, whether it's LNPs or other stuff. That's not the approach that we're taking. It's enhancing the chemical backbone to enhance cellular uptake, tissue uptake, so that we can look and see differential outcomes with these medicines.
That's helpful. Thanks.
Thank you. Our next question comes from Eun Yang with Jefferies. Your line is now open.
Thank you. Paul, I think that you guys, throughout the presentation, you guys touched upon this, but I want to specifically ask you one question. When you look at your prior DMD exon 51 program, preclinical data was remarkably great. It's very good, and it just didn't translate into humans in the clinical study. With this PN chemistry, with all those attributes that you guys talked about, how do you think about it's going to help you transfer it into better human outcome, human clinical testing results?
I appreciate the question, Eun, because I think the data that we showed today demonstrates the impact of a PN backbone change. Changing the fundamental structure of the drug, when all the other variables are kept consistent and we see an advantage. We see an advantage both in terms of potency, and that relates to dose, so that even in people studies that we're doing now at a substantially reduced dose. I think the DKO for us was a very helpful model to understand this, because it gives us a model that has a phenotype, I mean, it has a severe phenotype in terms of spinal, so we have to kind of overcompensate on that. I think the expansion into both new models as well as the advancement of new chemistry, continues to give us insight.
I think when we look at things from a very scientific point of view, I think what we take in every opportunity is an opportunity to learn, whether that's on clinical data or preclinical data. I think that the team is always looking to answer questions and to derive understandings and differences. I think the amount of work we've done in prosecuting how to advance PN chemistry has insight, not just looking at splicing, but as we look across the board, most recently with C9, where as we look out with the new durability data on silencing the DPR, the peptide, being able to see data out at six months and still sustained knockdown. I think there is a uniqueness in what we've built in terms of the chemical backbone that just continues to build on what we've built fundamentally on the platform.
Okay, thanks. Then with the new PN chemistry and ADAR programs, does that open up more opportunities for potential partnerships going forward? Thank you.
No, I mean, thank you, Eun. I mean, absolutely. I think what we've demonstrated today is whether we talk about various modalities, so moving in antisense, RNAi, exon skipping, ADAR, being able to utilize those across multiple therapeutic areas outside of neurology. I do think we're excited about building out our neurology franchise using a multimodal effort. We've got tremendous opportunity. The data that we showed, and that was why it was important for us to look at muscle, gets us expansion into heart and other tissues that gets us beyond thinking about just exon skipping and DMD, but thinking about opportunities much more broadly. Same thing as we think about the liver and the opportunities to think about the hepatic space in a very broad way, and multiple tissues there.
As we've had a number of conversations that have been going since sharing this information, I think the conversations are fascinating because I think we offer is the ability to think about multiple tools. As we think about some of the ophthalmology data we've shown, being able to think about working in the ophthalmology space where you have both tools of silencing and editing open up a tremendous universe. I think what we're able to do, both to commercial partners but also academic partners in terms of getting chemistry and exploring new target space that can be unlocked that hasn't been able to be unlocked before, really lets us explore partnerships in a variety of ways, expanding datasets and also expanding commercial opportunities for Wave.
Thank you.
Thank you. Our last question comes from Yaron Werber with Cowen. Your line is now open.
Hi, guys. This is Brendan on for Yaron. Thanks for organizing the event, and congrats. Just a couple quick ones from us. First, I actually really wanted to focus on the C9orf72 program. Can you just quickly kind of give us a sense of how solid the clinical assays are to detect the repeat-containing C9orf proteins in the CSF, and also the wild type protein separately? Are these kind of pretty well established or do you think it's going to require a little bit of optimizing like in the HD programs? Also, do you expect any kind of notable differences between the two indications, given that one is clearly more spinal cord centered and the other's looking more at higher brain regions?
I guess just the second question really quickly, if you have any idea, if you can let us know if there's just regarding the kind of kinetics between the C9 mutant knockdown and some of the biomarker changes, how long you would anticipate? Is this pretty quickly that you would think that get rid of the mutant-containing transcripts and you'd see pretty substantial changes in, say, NFL or some of the other ones? Thanks very much.
Hi, this is Ken. Thanks very much for the question. I think the assays for measuring the poly-GP dipeptide repeats are very well established and can be readily applied to our clinical program. There's not currently a widely used assay, quantitative assay, for measuring the C9orf72, and so that's something that will require some development should we choose to try and measure that in the clinic. I think what we've seen preclinically is that the candidate can access all parts of the CNS that are required for activity in both diseases, and so I don't know that we would expect to see any differences a priori with regard to activity in either ALS or FTD. I missed the last part of the question.
I think the speed of effect, I think was one of the questions.
The speed of effect. Yeah. If you look at the data we showed, what you see is onset of action is actually quite rapid. It's also quite persistent. I think the recent data we've generated showing pharmacodynamic response being sustained out to six months in the mouse really gets us excited about the potential for a prolonged dosing interval in patients, which I think the patients would certainly appreciate.
I think there was one last question around FTD and ALS and similarities, and I think based on literature.
Yeah, I mean, they're clearly a spectrum of disease from kind of pure ALS to pure FTD and then a range of clinical presentations in between. I don't know that we would expect to see any strong differences in activity throughout that spectrum. I think the molecule would work equally well in either disease.
I think the poly-GP level is the same. I think the idea of looking at those both and running that experiment is why we're excited to approach both indications simultaneously. I think a lot of the ways we think about it for C9 is in an analogous way to some more of like an oncology focus of go after the genetic target, more so than what the phenotype is, recognizing that you have these kind of multiple phenotypes. If we can develop our drug at the front end of thinking about it as a C9orf72 targeted therapy, then we target those diseases that have that mutation. Again, a different way of thinking about some of the CNS diseases that can be genetically stratified.
Okay, great. Thanks very much.
Thank you.
Thank you. This concludes the question and answer session. I would now like to turn the call back over to Dr. Paul Bolno for closing remarks.
Thank you everyone for joining the webcast and thank you to everyone at Wave for their hard work. We look forward to connecting with many of you after this call. Have a great day. Take care.
Ladies and gentlemen, this concludes today's conference call. Thank you for participating. You may now disconnect.