Thank you for standing by. Good afternoon, and welcome to the Ultragenyx Q3 Fiscal Financial Results Conference Call. At this time, all participants are in listen-only mode. At the end of the prepared remarks, you will have the opportunity to ask questions during the question-and-answer portion of the call. It is now my pleasure to turn the call over to Joshua Higa, Executive Director and Head of Investor Relations.
Thank you. We've issued a press release detailing our financial results, which you can find on our website at ultragenyx.com. Joining me on this call are Emil Kakkis, Chief Executive Officer and President, Erik Harris, Chief Commercial Officer, Mardi Dier, Chief Financial Officer, and Camille Bedrosian, Chief Medical Officer. I'd like to remind everyone that during today's call, we will be making forward-looking statements. These statements are subject to certain risks and uncertainties, and our actual results may differ materially. Please refer to the risk factors discussed in our latest SEC filings. I'll now turn the call over to Emil.
Thanks, Josh, and good afternoon, everyone. 2022 has been a year focused on execution for our team, both commercially and in our pipeline. We've made substantial progress across our key priorities and initiatives despite ongoing macroeconomic challenges. In the Q3, we continued to achieve strong year-over-year growth from our commercial programs and continued to broaden our commercial revenue base. In Latin America, we're seeing positive commercial and registry momentum across multiple countries with increasing revenue. In Europe, our launch of Evkeeza is underway, and we're seeing significant enthusiasm from lipid experts on the potential for Evkeeza to change the treatment paradigm. We've submitted already or will submit reimbursement dossiers in multiple countries and are beginning country-specific pricing discussions. We believe the enthusiasm of lipid experts for the product will help in supporting effective reimbursement discussions.
With regard to our pipeline, we acquired full control of the GTX-102 program on promising signs and the interim phase I/II data we shared in July. We continue to be encouraged by the progress of patients in the program and the safety profile with 10-12 mg doses now being used in maintenance. Over the next few months, we anticipate completing enrollment in the phase III study for GSD1A, which has enrolled very well with the enthusiasm of patients for a new treatment option.
We also plan to complete enrollment of the phase II portion of the study for osteogenesis imperfecta in mid-2023, which should give us data on the bone biomarker response of two dose levels. Last month, I visited our gene therapy manufacturing facility outside of Boston with the Ultragenyx Board of Directors, and we were hosted by our team building the plant.
I continue to be impressed with the quality of their work and the fact they've met or exceeded our timelines and maintained costs within budget for this greenfield project. Despite the pandemic and global supply chain issues, the facility has remained on track to begin manufacturing operations next year and should be a big boost to our gene therapy franchise. We've also been focused on laying a solid financial foundation for the years ahead. In July, we raised $500 million with sale of a portion of our Crysvita royalty and have established additional cost controls, limiting headcount, operating expenses as well into 2023. We believe we have the right team in place to achieve our priorities, and we'll actively manage our headcount and spend while achieving these objectives.
Erik will provide more specifics on the commercial team's performance in the Q3, but I wanted to briefly touch on our partnership with Kyowa Kirin. We have worked closely with our partners throughout commercialization process to make Crysvita a very successful rare disease launch. We recently amended our collaboration agreement to allow both companies to be in the U.S. field for an extended period of time, ensuring the U.S. Crysvita franchise will continue building on the solid foundations we have established. In the press release we issued earlier today, we shared details of the amendment that increases our joint commercial effort for one year after the transition of commercial responsibilities through April 2024.
Under the revised terms, KKNA recently began field operations ahead of the transition, and Ultragenyx will maintain a consistent presence here in the U.S. for an additional full year until April 2024 after the transition to further increase field coverage. The surge of additional efforts should help with identifying more XLH patients and providing them an opportunity to be treated, and highlights each partner's commitments to maintaining continuity with the Crysvita franchise. During this time, Ultragenyx sales force expenses will continue to be shared with KKNA. In addition, Ultragenyx will continue to call on medical geneticists in North America after that transition and indefinitely based on the original terms of our collaboration agreement. We'll co-lead the XLH and TIO disease monitoring programs in partnership with KKNA.
Medical genetics are an important segment of healthcare providers who treat patients with XLH, and many of the diseases targeted by our other clinical stage programs. With that, I turn the call over to Erik to provide more specifics on the commercial performance for the quarter.
Thank you, Emil, and good afternoon, everyone. I'll focus my section on the commercial team's efforts in the Q3, supporting Crysvita, Dojolvi, and the upcoming launch of Evkeeza across Europe. For Crysvita, within a profit share territory, we continue to see meaningful increases in key metrics, including the number of start forms, patients on reimbursed therapy, and unique prescribers. In the Q3, approximately 120 start forms were completed. This is particularly impressive given the last time we saw this type of increase in any given quarter was in early 2021. These start forms have led to a steady increase in the number of reimbursed patients on therapy driven by an ever-expanding base of unique prescribers. In the Q3, approximately 60 new healthcare providers wrote a prescription for Crysvita.
We are well over four years into the launch of this rare disease product, and I applaud the team's continued efforts to find those community-based physicians as we are increasingly finding more adults with community physicians. Almost 50% of our new patients are now coming from new prescription writers, while the other 50% is coming from existing prescribers. We are focused on increasing face-to-face activities and educating physicians as we come out of COVID and as many new offices are now open to seeing our field personnel. While our team has been working closely with Kyowa Kirin for several years, the recently signed amendment allows us to work side by side in the field to ensure we can maximally support our patients during this transition.
The combination of additional KKNA sales specialists beginning last month and the extension of our US field team through April 2024 enhances Crysvita's long-term potential. Outside of the profit share territory, Crysvita was recently approved in Argentina for the treatment of XLH in adults and children six months and older. This therapy is now approved in five countries in Latin America, including Argentina, Brazil, Chile, Colombia, and Mexico. Brazil continues to be the largest market in Latin America, and while the uneven ordering patterns drive some well-known quarter-to-quarter variability, the underlying demand continues to grow at a steady pace. Across all of our Ultragenyx regions, Crysvita revenue in the first nine months of 2022 grew 34% compared to the same period of 2021.
We know the underlying demand is strong and supports our full-year revenue forecast, and we are reaffirming our 2022 Crysvita revenue guidance in Ultragenyx territories of $250 million-$260 million. Turning now to Dojolvi and beginning with the efforts in the U.S. Many of the leading indicators, including number of start forms and patients on reimbursed therapy, continue to exceed our expectations. As of the Q3, we have received approximately 400 completed start forms with over 340 patients on reimbursed therapy. Since launch, approximately 180 healthcare providers have written prescriptions for Dojolvi, with nearly half writing for more than one. Despite these strong metrics, there is an opportunity to continue educating healthcare providers on the benefits of optimal dose titration as supported by our clinical studies to assure patients are receiving an optimal dose.
Outside of the US, demand for Dojolvi continues to be led by named patient and early access programs in Europe, particularly in France and Italy. In Latin America, Dojolvi is currently approved in Brazil, where we are continuing to work through the process to get full reimbursement approval. In Mexico, we recently received orphan product recognition, which is similar to receiving approval with a few benefits that will enable us to get this important therapy to patients even faster.
While we continue to work to address the need for better dose titration for maximal effect in the US, at this time, we are reaffirming the guidance range we set at the beginning of the year of $55 million-$65 million. Closing briefly with Evkeeza, which we are preparing to launch in Europe, followed by Latin America, Canada, and then Japan, for patients with clinically diagnosed homozygous familial hypercholesterolemia.
The data from Regeneron's pivotal study for Evkeeza were very impressive. The drug demonstrated a significant improvement over standard of care with a 49% reduction in LDLC on top of all existing LDL-lowering treatments. The study also showed Evkeeza reduced LDLC by 72% in the most severe patients with less than 2% of LDL receptor activity. Feedback from key opinion leaders is very positive, especially those who participated in the clinical studies and have seen the value of this novel mechanism of action for their patients. They understand that Evkeeza blocks ANGPTL3, which enables a proven alternative pathway to convert VLDL into remnant cholesterol that can be easily cleared by the liver. This bypasses the normal lipid metabolic process that leads to dangerously high levels of LDLC in these patients.
Across Europe, we are in the process of filing reimbursement dossiers and look forward to beginning the country-specific pricing discussions. In parallel, we are evaluating requests for named patient access, which could generate the first orders later this year. In summary, the global commercial team is delivering on our mission to being a leader in rare disease by ensuring access to Crysvita, Dojolvi, Mepsevii, and now Evkeeza to all patients who could benefit from these therapies. With that, I'll turn the call to Mardi to share more details on the financial results for the quarter.
Great. Thanks, Erik. Earlier today, we issued a press release that included financial results for the quarter, which I will briefly summarize. Company revenue for the three months ended September 30, 2022 totaled $90.7 million. Crysvita revenue in Ultragenyx territories was $64.5 million, including $51.3 million from the North American territory and then product sales of $13.2 million in other regions. Total royalty revenue related to the sales of Crysvita in the European territory was $5.4 million. Dojolvi revenue for the Q3 2022 was $13.3 million. Mepsevii revenue for the same period was $6 million.
Total operating expenses for the Q3 2022 were $315.8 million, which includes R&D expenses of $237.3 million, SG&A expenses of $69.8 million, and cost of sales of $8.6 million. Operating expenses for the quarter included non-cash stock-based compensation of $35.8 million and a one-time R&D expense of approximately $75 million related to our acquisition of GeneTx. For the quarter ended September 30, 2022, net loss was $245.1 million or $3.50 per share. It's important to highlight a handful of non-cash items that have impacted net loss during the first nine months of the year.
This included approximately $101 million of stock-based compensation, $27 million of non-cash interest expense related to the Royalty Pharma and OMERS transactions, and $21 million related to the decline in fair value of our equity investment in Arcturus Therapeutics and Solid Biosciences. These are offset by approximately $16 million of non-cash revenue related to the EU royalty. We ended the quarter with approximately $1 billion in cash equivalents and marketable securities. While we are well capitalized, we are also continuing to make strategic operating decisions to manage our cash burn rate. As we have said, 2022 is a peak burn year for us as we have initiated multiple late-stage clinical programs in licensed Evkeeza, completed the acquisition of GeneTx, and are completing the build-out of our gene therapy manufacturing facility.
As Emil mentioned, in the Q3, we began the process of implementing initiatives that will limit headcount and operating expenses as we head into 2023, while maintaining focus on our key value drivers. With that, I will now turn it over to Camille.
Thank you, Mardi, and I too wish everyone good afternoon. In the Q3, we continued to advance one of the most diverse and late-stage clinical pipelines in rare disease. We also have made a number of strategic changes to our clinical studies that will enable faster enrollment as well as interim data cuts of the data from our pivotal programs. Of the programs currently in the clinic, I will briefly touch on GTX-102, phase I/II for Angelman syndrome, the UX143, phase II/III for osteogenesis imperfecta, and a few of the gene therapy programs. Starting with GTX-102 for Angelman syndrome, we continue to enroll and dose patients in the dose escalation cohorts of the phase I/II study.
Thus far, 13 patients have received a cumulative dose of at least 20 milligrams, and 14 patients have had over 132 days of exposure to GTX-102, with no reported serious drug-related safety events, including no reports of lower extremity weakness. Crossing these thresholds safely is important as the original five patients experienced lower extremity weakness at a minimum cumulative dose of 20 milligrams and at an exposure up to 132 days. This continues to give us confidence that the amended dose administration strategy and slower titration may allow us to safely recreate the efficacy seen in the original 5 patients. We also have redosed the first two patients from the originally treated US cohort with at least two doses each in Canada, including one that previously had a significant lower extremity weakness event.
These patients are doing well, and there have been no reported serious drug-related safety events, including no lower extremity weakness. We are continuing to work through the process of aligning the US and ex US protocol and intend to have clarity in the next few months. We expect to begin enrollment in the expansion cohorts in the H1 of 2023, and we'll provide a data update once we have gathered substantial data from the cohorts. Turning now to UX143 or setrusumab for osteogenesis imperfecta. The anti-sclerostin mechanism of setrusumab has the potential to reverse the majority of the bone's maladaptive response to collagen mutations and strengthen bones substantially. We have a particularly strong belief in the value of this mechanism for patients with osteogenesis imperfecta.
For our ongoing setrusumab study, we recently amended the pivotal phase II/III protocol to remove placebo from the dose-ranging phase II stage of the study to enable us to do real-time analyses of the program. We believe this change, along with activating the last few sites, will allow us to complete enrollment of the 24 patients in this stage of the study in the next few months. Data from this portion of the study are expected to be available in mid-2023, including the two-month changes in bone biomarker response that will establish the phase III dosing algorithm. Concurrent with the data readout, we plan to transition to the larger randomized phase III portion of the study.
Moving to our gene therapy programs and starting with DTX401 for the treatment of glycogen storage disease type Ia, which we are currently evaluating in a pivotal 48-week randomized double-blind placebo-controlled phase III study. This program was recently granted PRIME designation from the European Medicines Agency or EMA. This designation provides opportunities for additional interactions with the agency and could lead to an accelerated approval pathway.
Recall earlier this year, we focused resources on enrolling this study, and these efforts have helped increase the rate of enrollment. We currently anticipate completion of enrollment around the end of the year, with phase III data approximately one year thereafter. Turning now to UX701 for Wilson disease, which continues to enroll patients in the dose-finding stage of the pivotal study. Similar to UX143, we recently removed the placebo from this stage of the study.
While the protocol dictates a progressively shorter observation period between each patient, we expect to complete enrollment of this stage in mid-2023 and plan to share data on safety and initial signs of clinical activity in late 2023 or early 2024. The last program I'll mention in my prepared remarks is DTX201 for hemophilia A. As part of a regular review, Bayer has decided to discontinue development of this program and return the rights to Ultragenyx. We continue to believe that this is a better version of Hem A gene therapy if in the right development hands.
We will not initiate further development of DTX201 without a partner, but we would be interested in a quality partner that has the clinical expertise in rare hematological disorders and an interest in developing a high-quality AAV Hem A therapy. We will continue to monitor the hemophilia A gene therapy landscape and explore our options with respect to potential partners. With these updates, I will now turn back the call to Emil. Thank you.
Thank you, Camille. Before we shift to the Q&A portion of the call, I'll provide a quick reminder of the upcoming milestones. We expect the GSD1A phase III to be fully enrolled around the end of the year based on how well it is enrolling now, with the data to be shared approximately one year later. For UX143 in osteogenesis imperfecta, we expect to complete enrollment of the dose-finding stage in the next few months and expect to share phase II data and transition to phase III in mid-2023. In GTX102 in Angelman syndrome, we're highly encouraged by the progress and expect to begin enrollment of large expansion cohorts in the H1 of 2023 and plan to provide a data update once we've gathered substantial data in 2023.
Lastly, UX111 for Sanfilippo syndrome, we're continuing to evaluate biomarker and other data generated by Abeona and are finalizing an approach to FDA regarding filing for approval based on this current data. These clinical catalysts, our commercial teams' continued execution in the field, and the cost control measures Mardi mentioned put us in excellent position to deliver meaningful value to patients and shareholders. With that, let's move on to your questions. Operator, please provide the Q&A instructions.
Certainly. Ladies and gentlemen, if you do have a question at this time, please press star one one on your telephone. We ask that you please limit yourselves to one question and one follow-up. You may get back in the queue as time allows. Our first question comes from the line of Gena Wang from Barclays. Your question please.
Thank you for taking my question. I have one regarding the Angelman. Since I think a press release, you said you were dosing in expansion cohort in H1 2023. Does that mean the cohort six and seven showed a sufficient CGI score improvement that you don't need to do the further dose escalation? What will be the timing for next data update?
Yes. Well, we're not now gonna be commenting on the data from the dose escalation cohorts. We're just giving you general timing of when we'd get to the expansion cohorts. We'll provide more data on the whole program looking at the dose cohorts and expansion cohorts when we feel it's an appropriate time, but we're making good progress. We're encouraged.
Okay. Also, quickly for two patients who received two doses each in Canada, what doses did they receive, and how frequent was the dosing?
Well, they initiated on the protocol that we had in place for cohorts four and five, the same protocol depending on their age. That was either the 3.3 dose to start or the five dose, the same one. One received two, and the other received four doses, I think, already. The important thing is they've had no adverse effect at all, and we're encouraged by how they're doing. There're more patients that wanna get treated. We're hoping to get the other ones treated.
Great. Thank you very much.
Thank you. One moment for our next question. Our next question comes from the line of Joseph Schwartz from SVB Securities. Your question please.
Hi. I'm Julie Dalian in for Joe. Thank you for taking our questions. The first one is on GTX102. I believe that you previously guided to cohort six and seven expansion update in late 2022 or early 2023, but it looks like you will begin enrollment in the H1 of 2023. I was just wondering if there are some things that need to be done in order to begin enrollment in the H1 of 2023.
Well, they've been already enrolled. What we said is we're completing enrollment of those cohorts and initiating the expansion by early in the year. That's all underway. We've decided not to provide more point-by-point progress. What we said before is that we would announce data when we had a substantial amount of data rather than dribbling out bits of data with each cohort. We're gonna wait till we have a substantial body of data, but we're encouraged by the progress.
Okay, got it. As a follow-up, I guess, in the press release you mentioned that discussions with the FDA to harmonize the U.S. and ex-U.S. studies are ongoing. I was wondering if you could provide some color on what the FDA is looking for in order to make this happen. Thank you very much.
Well, we previously noted that we had provided some information before to FDA, and they wanted a complete set of data in the terms of a CSR, which we've prepared, and we are working through the process. We usually don't go through the details of the back and forth, but we'll provide the report and other information that they requested, and we hope we'll then be sufficient to reopen the US study, US sites to run the current study. That's ongoing. They wanted just a more complete set, and we've been preparing that for them.
Thank you. One moment for our next question. Our next question comes from the line of Christopher Raymond from Piper Sandler. Your question please.
Hey, thanks. Just two questions. First on DTX-401. Just thinking about the European re-review process and the PRIME designation. I know you guys have announced this before, but just looking back at the prior data, you guys saw corn starch use reduction pretty meaningfully at even week 24. I'm just kind of curious with this review, is there any chance of an interim look here to serve as the basis for an accelerated approval, or is that just sort of totally off the table? Then on setrusumab, I know you guys sort of talked about a protocol amendment. Can you just clarify, is that the reason for the delay in finishing enrollment of the phase III? Just to kind of clarify that. Thanks.
Okay. With regard to DTX401, we have to serve both US and Europe, and the trial is blinded. Even if six months data were better, we had committed to 48 week's worth of blinded data for both. There's no way to use that to accelerate. Once we get our blinded complete data, though, the PRIME designation will help us, you know, accelerate the review discussion process to get to a file. That would be the main benefit of it. We couldn't use that to shorten the study. We'd have to honor the 48-week blinded main body of the study. For setrusumab, I would say, look, in general, all year, because of Omicron in the beginning of the year, sites are under stress.
I think a lot of people have had, you know, challenges getting studies going, and we've managed that. We're pushing ahead. We are enrolling the study. The placebo, though. Removal of the placebo just gives us an opportunity to see what's going on each patient. We're doing a wide range of ages, and we'll be able to see data all along while the study's going on in more real time, allow us to help kind of think through the dosing. I don't think we're just picking one dose. It could be a do-dosing algorithm like that different ages get different doses. Being able to see the data in the file will just help us get through that and get through it faster.
When we get the final bit of data in, we can make a decision on whether we need to go higher for the younger patients and for what ages. It's a main benefit to us. With the data, though, we'll be able to inform the street what the drug looks like as well in the younger patients. It will help us also with raising awareness of the drug and its potency for people globally. When you look hard at anti-sclerostin as a strategy and all the data, both animal and human, it's a very profound effect in a very important way for OI. That's why we think having the dose data probably will be also helpful to us in raising awareness and driving our phase III.
Thank you. Our next question comes from the line of Tazeen Ahmad from Bank of America. Your question please.
Hi, good afternoon. Thanks for taking my question. Just a point of clarification for UX143, for your OI indication, can you maybe, Emil Kakkis, set for us expectations on what you would consider to be clinically meaningful data? Just remind us about how large you think this population could be for adult patients. Secondly, to clarify, when should we expect to see phase III data for DTX401? Thanks.
Sure. Let's start with the size. For the UX143 or setrusumab should address both Type I, Type III, and Type IV OI in that group. Which is very amazing and powerful to be able to do all three types. That would allow us to treat on the order of 60,000 patients in developed world. Essentially larger than what XLH is, calcitonin. It's a very meaningful population. Within the study, the first part of the study, the phase II, will help establish the right dose, and we'll have biomarker-driven data basically to make that decision. For the phase III with the FDA discussion, the main 301 phase III will be looking at clinical fractures, rate of clinical fractures, between the treated and placebo group.
We're also going to be running another study, a 314 study, which will look at a younger age group with very high fractures, which we'll randomize to setrusumab or bisphosphonate, which is used in those very severe young patients, which gives us another way to demonstrate the powerful effect, particularly in the young patients, where from our own experience in rare bone diseases, the young patients can really respond to a new drug in a profound way. We think it's another way for us to demonstrate the product. That study will be open label but randomized. That one will look at total fractures. Both of them are looking at fractures, one clinical fractures, the other total fractures.
Well, bisphosphonates have failed three out of five times studied, but the proximate effect is maybe about 20% reduction in fractures. We think that this drug will have about a 50% reduction in fractures, and that's how we've powered the studies. We think that certainly would be clinically meaningful. Right now, I think that there's probably more to the disease than just fractures, and we'll be looking at a number of endpoints which will help enhance the clinical meaningfulness, like how patients feel, how they respond, because we think those are in their day-to-day life things. Those will have impacts on how well the drug will be used and how important it is in their lives.
Thank you. Our next question comes from the line of Dae Gon Ha from Stifel. Your question please.
Great. Good afternoon. Thanks for taking my questions. One clarification question on the KKC amendment. So perhaps for Mardi, does the extension to April 2024 also apply to profit share or just cost share? I guess in another way, transition to royalty base, should we expect that to occur starting in April 2024 or April 2023? As a follow-up for GTX-102, just wanted to clarify, have any patients reached the 14-milligram dose at this point? Thank you very much.
I'll go first. Just jump in. Very straightforward. The royalty structure takes place at the initial time of transition, so April 2023. That we'll have the amendment. We will be able to have additional folks in the field to help, you know, to make sure we have a smooth transition, and we continue to grow Crysvita, and that will be under the cost-sharing arrangement.
With regard to the Angelman GTX-102, there is one patient that's reached 14 in the titration, but there's a large number of patients and many have received 10 and 12 from the earlier cohorts. We've achieved a significant level of drug without having a side effect, and we're encouraged by what we're seeing.
Thank you. Our next question comes from the line of Maury Raycroft from Jefferies. Your question please.
Hi, congrats on the update, and thanks for taking my questions. For Angelman, I wanted to see if you can clarify how many new patients have been dosed since the data cutoff in July for July twelfth.
Yeah, I don't think we can give you that precise detail. You're all trying to triangulate it around. We're working through the dose escalation cohorts, which can be two-four patients, but in each one. We said we're gonna be through them and expecting them fully enrolled before the end of the year. Early H1 we would be doing the expansion cohorts, which is the larger 20 group expansion. That's kind of where we are. We won't provide any more detail than that at the moment.
Got it. Also for Angelman, there's been some discussion on potential CGI score discordance in the United States versus EU and Canada. Do you have a strategy in place to standardize assessment and reduce bias across sites for the CGI measure?
Yeah, certainly that's a question that's fair to be raised. I think we're working on additional training to ensure that we're normalizing that. I would say also, though, that reliance on the third party, like the psychologist assessments that's done with a region-specific calibrated scoring system where you're measuring performance and scoring, is the one way to gain the kind of objectivity. We've shown some of that data, for example, in the Bayley score or the Vineland score. The Bayley score particularly is because it's psychologist administered, not the PI, not the parent. I have a combination of training and also dependence and reliance on some of these independent scores that help give us confidence that what we're seeing is an important effect and not a placebo effect.
Thank you. Our next question comes from the line of Yigal Nochomovitz from Citi. Your question please.
Hi, Emil and team. Thank you very much for taking the questions. I had one on the commercial business, I think maybe for Mardi. Just regarding the guidance range for Dojolvi. For the Q4, it looks like you need a significant re-acceleration in the trajectory to meet the lower end of guidance. If you could just spend a few minutes just clarifying the assumptions around getting into that guidance range. Thank you.
Sure. I mean, I'll start, but then Erik is here as well, and he can give some commentary on just what's going on with Dojolvi. You know, we always it hasn't been launched for that long. What we've seen with actually both Crysvita and Dojolvi is that you do indeed have a heavier Q4 as a percentage of the total revenue. You know, we expect that we're given the health of the business and the growth that we've seen and the start forms and the number of patients treated, we expect that again going into the Q4 this year for Dojolvi and Crysvita, mind you. Erik, I don't know if you wanna give any more commentary just on Dojolvi and how well we think it's doing.
Dojolvi, demand is strong, and as I have stated, you know, it continues to exceed our expectations with regards to identifying patients and converting those patients to commercial therapy in a timely manner. You know, the challenge that we're working on is optimizing the dosing. We have an educational campaign underway at this time to increase awareness and working closely with both patients and providers around optimal dosing and timely titration of the treatment.
Got it. Just one quick follow-up on the pipeline. I thought it was interesting that both for the antibody setrusumab as well as for the gene therapy in Wilson's disease and the totally unrelated disease, you removed the placebo part for the dose finding. I'm just wondering if there's any connection between those decisions or if they were just independent and coincidental. Thank you.
They're independent and coincidental happen to be running four trials at the same time right now. They're all at the same stage. We always seek to have the more perfect design, which I think a placebo can be considered that. Sometimes the practical reality is that actually inhibits your ability to know what's going on and learn and do things. We felt like it was gonna be better for us to learn what was happening on the fly and maintain the placebo for the main body of the study, but simplify the upfront part.
It also makes it easier to be able to talk to patients about enrolling in the program, because if they haven't seen the drug and the doctors didn't know anything about it just helps with that discussion. It's totally separate. Just happens to be we're at the same stage for everything, and we're adapting what's the best way forward to get this drug enrolled and advanced as fast as we can.
Thank you. Our next question comes from the line of Joon Lee from Truist. Your question please.
Hi. Thanks for taking our question. You mentioned cost alignment for 2023. Can you outline which areas you're focused on and any comment on cash runway? For 102, is multi-domain responder index a possible way to mitigate noise given your expertise there? Thank you.
I'll start with expense, and you can provide a little more detail.
Yes, sure.
The main job here is to not spend money in plays that don't create value. That's our big thing, and to really drill harder down on that in our growth. We've had a lot of growth. We need to manage it. Maybe Mardi Dier can provide some more color on that.
Yeah, sure. We mentioned headcount, for example. We have had a lot of growth, you know, for the past couple of years, starting really with the Dimension acquisition. Our goal is to limit headcount and keep headcount flat going forward as well as our operating expenses as well. Our goal would be to keep OpEx flat going into 2023 as well. To do that is exactly what Emil was saying. You know, looking where we can drive value and prioritize and not spend money where on things that perhaps would not drive the value that we want in the near term. I think that's good housekeeping, right?
We've had this period of growth, and these are programs that we're implementing, and I think we'll see results, or we've already seen results. That's great. From a cash runway standpoint, you know, we are in good shape. We have about $1 billion on the balance sheet, and that takes us, we haven't given specific dates, but we always say the next couple of years and definitely through some critical milestones, on questions you've asked about 102 and 401. From a cash standpoint, we feel lucky in that we're in good shape. We wanna take care of that cash, moving forward.
Thanks, Mardi. On the MDRI, the multi-domain responders, for those of you not familiar with that, is a way of essentially evaluating many different domains and capturing big wins or big changes in a very heterogeneous population. We think Angelman is a prime disease state, given the fact that there are multiple different domains, five or six domains of clinical importance that you could evaluate. You evaluate with given endpoints, and you add up the big wins through a minimally important difference filter. We think that method allows you to capture efficacy that might vary between patients in a population, which would allow us to not have to select the population carefully for the particular thing we're looking at. It's one way forward.
I would say to you that if you're using a Bayley's or other types of third-party measure tests, and you have professional measures who do the assessments, that you can get control as well, and you can imagine having a Bayley receptive and expressive communication score, for example, as a primary endpoint. It's certainly potential. We're gonna look at all those options and work through it. The MDRI is not widely accepted by FDA. We did use it in Mepsevii.
They're aware of it. We've had a lot of discussions at the senior level there. There's a lot of good features to it, and it could be something that would be great for a disease like Angelman where there's lots of heterogeneity. It's in the palette of options right now, but we have time to figure out. There's so much going on in Angelman that it's not a problem to figure out the endpoint. It's really a matter of trying to optimize how we capture efficacy across a heterogeneous population.
Thank you. Our next question comes from the line, Yaron Werber from TD Cowen. Your question please.
Great. Thanks for taking my question. Maybe Emil, just on that point, you know, FDA, as you know very well is very much a fan of the ORCA for communication, and I believe they even gave a grant to validate that endpoint to an academic site. Can you just give us. And I believe they might even accept it as a primary endpoint on communication. Where is that toward validation? And is there any chance you might explore that or that requires validation as a priority, and that's gonna take too long? Then maybe just secondly, once you do select a dose, would you move to sort of a placebo phase II before you run the pivotal? Thank you.
Well, we're familiar and we're running the ORCA, and we've seen improvements in the ORCA. I think the ORCA is near. The validation will be done. I think it's either done now or is going to be done, so I think that all will happen. The thing I would say to you is when you look at clinical development, that putting a caregiver assessment as primary is a tricky thing because it can be critiqued and is complicated, and often there's noise, in fact, with caregivers assessments in this regard. I would generally putting it as a sole primary endpoint, I think would be a challenge. I would much rather see an independent professional evaluation score that. But you miss something when you have a professional evaluator, like the setting is not comfortable. It might alter how patients behave.
We're aware of all that. We have time for us to figure it out. I think ORCA could very well be one of the components of the language, whether it would be primary. I would be less comfortable with it being a primary. But the validation will happen. It'll be an important part of the overall assessment of how patients do.
The second question was around the phase II, would we introduce placebo?
Yes. That's right. Well, our plan right now does not include running additional phase II placebo trial. The fair question you're asking, Yaron Werber, really is how do we know the treatment effect we're seeing is sufficiently large to not be placebo? It's been a common discussion item for a lot of people, but I think we're gonna be looking for an efficacy change that we feel is compelling and persistent. The kind of thing we think we have seen gives us confidence we can get that kind of data. If the data were less certain, then it would raise more questions about whether we have the dose right or not, frankly, because I don't think we wanna enter phase III unless we have a definitive treatment effect that we're comfortable is worth investing in.
If there was need for that, we could consider it, but right now we're looking for really solid, large amount of efficacy before we head to phase III. That would be our preference. Your point's well taken, but I think that, if we can get the kind of efficacy that is incontrovertible in our minds, then we'd move right to the phase III.
Thank you. Our next question comes from the line of Salveen Richter from Goldman Sachs. Your question, please.
Hey, good afternoon, and thanks for taking our questions. This is Elizabeth on for Salveen. For the Wilson's data update around the end of next year or early 2024, could you provide color on what signs you're looking for? On the OTC program, if you could discuss how you expect enrollment to progress. Thank you.
Certainly. For the Wilson update, what we'll expect to have is we're planning to enroll five patients in each of three cohorts, now all open label, so we'd have 15 patients worth of data. We'd expect the update to include data on the different dose cohorts that would tell you about urinary copper, ceruloplasmin, and other parameters that relate to copper physiology, metabolism in Wilson. Those would be the core measures that would be telling us are we hitting the right dose and what our dose is going forward and what the safety looks like in that population. That's what we'd expect to put out at that time. For OTC, we consciously put OTC after GSD1a in startup enrollment, running as many trials as we are.
We pushed it out, allowed the GSD one to be our prime focus to get it going and enrolling, which it has. We'll now be adding more effort on OTC to get that enrolled. It is a 64-week study, so it's a little bit longer. It will take more time to enroll, and we'll probably have to enroll more outside the U.S. than in the U.S. is our expectation. It's still a 50-patient randomized trial and it will take somewhat more time than GSD probably to enroll.
Thank you. Our next question comes from the line of Joel Beatty from R. W. Baird. Your question, please.
Thanks. For Crysvita, I think you mentioned that about half the new scripts are coming from new prescribers. How does the remaining addressable market split across new prescribers and existing prescribers? A second question is on the hemophilia B program returned from Bayer. What could make that attractive to a new partner?
Well, let me answer the second one first, and then Erik, you can answer the first one. On what came back to us was our hemophilia A program. They had acquired significant data, had a number of patients who had great reduction in events, and they decided it wasn't meeting with criteria they wanted, and they had other priorities. They decided to bring it back to us. What we're looking for is first of all, we have a lot on our plate as a company, and we don't wanna put more money into an area where we're not experts. We think hemophilia still has room. We think BioMarin program is getting there, but we think there's still room for a better gene therapy.
We do think that the capability in our manufacturing, large scale manufacturing process would be, I think a benefit. We'd be looking for a partner who wants to pick up development, and we'd be happy to do the manufacturing. We have a new plant as well, which would give us an edge. We'd be looking to use our Pinnacle PCL platform then to manufacture that product. We think that there's still a lot of room left for something better. Erik, why don't you answer the question on the prescribers?
If you think about the current market penetration for pediatric patients is about 40% and adult patients is about 15%. We continue to believe that the majority of the pediatric patients will get treated. About 50%, half of the adult patients will eventually end up on treatment. As we've been stating, many of these patients that we're finding these days, if not most of these patients, are in the community setting.
With doctors that are not necessarily associated with the traditional metabolic bone center. It takes time to find those patients and get them referred to someone that will either treat them or initiate treatment for new prescribers.
Thank you. All right. Our next question comes from the line.
Go ahead, next question. Thank you.
Liisa Bayko from Evercore ISI.
Hi there. How are you doing?
Hi there.
I just wanted to ask a couple questions on Wilson disease. I see you've just amended the trial design, and you'll be able to evaluate a couple of preliminary doses. Can you talk about any potential signals that you'll be looking for in that data to evaluate if there's any efficacy? Like, what should we be looking for in this initial data set, and will there be any breakthrough in efficacy?
Well, first of all the patients in the trial would have been on stable chelator therapy for a while, so they already have sort of drained their copper. We're gonna be looking at urinary copper and then urinary copper after you remove their drugs at some point. The first part, we're looking at whether we're reducing the amount of copper that ends up in the urine with their chelator versus not. We'll also be looking at copper-loaded ceruloplasmin or ceruloplasmin activity. That will tell us how much copper is getting loaded on ceruloplasmin, which is very low in Wilson. It's one of the unique features of gene therapy is that we can restore normal copper distribution, which you can't do with a chelator. We think that's a really important feature.
We showed in the animal model that we could get to, you know, significant increases in ceruloplasmin loading and delivery. So that's an easy measure from the bloodstream. Combine that with urine copper, serum copper, and probably a few other biochemical measures. That will be the basic way we'll make the decision on dosing. So, it'll be urine copper, serum copper of various types, as well as ceruloplasmin, I think is at the core of it. Of course, there's safety, you know, transaminase and safety and, how patients are doing, overall, but I think most of its gonna be driven off copper biochemistry.
Okay. Would that be kind of the regulatory endpoint as well? Or, is that? Maybe you could just give us some little background. I understand it's, like, critical to the disease. Just curious on how relevant it is for the bigger picture.
Yeah. The regulatory discussion focused on urinary copper. Although some people have been using plasma or free copper, the agency actually preferred urinary copper, and that is the accepted primary endpoint to look at urinary copper control. We'll do it while they're on their drug, but we're also gonna take them off their drugs and controls to show that we can keep urinary copper low while they're getting less, they won't have any copper chelation going on.
Does that make sense? We'll be able to show to get rid of their old treatment and then use the new treatment and still maintain low urinary copper. That is the agreed upon evaluation. It's one advantage of the Wilson program is that there were clear biomarker-type endpoints that are meaningful that the FDA has already accepted because of the use of chelators in their prior approvals.
Thank you. Our final question for today is a follow-up from the line of Yigal Dov Nochomovitz from Citi. Your question please.
Hi. Thanks very much for taking the follow-up. I just wanted to follow up on your own question around the placebo for an Angelman's phase II or phase III. As you know, in the prior Ovid trial, the placebo effect was around 0.8. That was a mixture of deletion and mutation patients, as you know. I'm assuming that if you do a phase II or phase III, that you'll only enroll the deletion patients. Based on some of our analysis of the literature in Angelman's, it would suggest a placebo effect substantially below 0.8. Just wondering what your thoughts are on that, and if you could confirm that if you do a pivotal trial on Angelman's, that it would be 100% deletion patients. Thank you.
Yes. Our pivotal plan is to do all deletion because we think including a variation of type will create a lot of variances, not only around the CGI score, but also around all the other scores. The last thing you want. There's already a lot of heterogeneity. Do you want more heterogeneity? The phase III will be strictly the deletion type, which is 70% of the population. We'll conduct some other companion studies that would help expand and understand the use of the drug in the other types like UPD, uniparental disomy, or the missense type of patients. We will wanna cover the whole thing for the label, but the randomized study will focus on the severe population.
Honestly, if we can prove in a placebo-controlled that we're treating severe population, the other stories will be easy to reach consensus. I think controlling noise is extremely important in these types of designs , and by mixing types, even though it might, even if regulators want it, I will resist it because it's, it could harm your outcomes and create a more effect. If you look at natural history in the severe patients, they are very flat. They do not change. They do not gain ground on expressive or receptive communication, significant ground. We think by not mixing with some patients who do gain some ground on expressive or receptive, you will avoid that noise. It is part of our strategy just to keep it tight and therefore be more confident about the effects we're seeing.
Thank you. This does conclude the question and answer session of today's program. I'd like to hand the program back to Joshua Higa for any further remarks.
Thank you. This concludes today's call. If there are any additional questions, please at Ultragenyx.com. Thank you for joining us.
Thank you, ladies and gentlemen, for your participation in today's conference. This does conclude the program. You may now disconnect. Good day.