Good morning, and welcome to Cellectar Biosciences conference call with Dr. Yair Levy to discuss his perspective as the community-based hematologist on the top-line results of Cellectar's CLOVER-WaM pivotal study that were released last week, Monday. Today's call is being recorded. Before we begin, I would like to remind everyone that statements made during this call relating to Cellectar's expected future performance, future business prospects, or future events or plans are forward-looking statements as defined under the Private Securities Litigation Reform Act of 1995.
Although the company believes that the expectations reflected in such forward-looking statements are based upon reasonable assumptions, actual outcomes and results are subject to risks and uncertainties that could differ materially from those forecasts due to the impact of many factors beyond the control of Cellectar. The company assumes no obligation to update or supplement any forward-looking statements, whether as a result of new information, future events, or otherwise.
Participants are directed to the cautionary note set forth in today's press release, which is available on the Investor Relations portion of the company's website, as well as the risk factors set forth in Cellectar's annual reports filed with the SEC for factors that could cause actual results to differ materially from those anticipated in the forward-looking statements. Now, I would like to turn the call over to Jim Caruso, President and Chief Executive Officer of Cellectar. Jim?
Thank you, operator. Good morning, and welcome, everyone. Last week, we announced the full enrollment of the CLOVER-WaM study and reported the exciting top-line results from our pivotal study evaluating iopofosine I 131 in relapsed or refractory Waldenström's macroglobulinemia, or WM. As previously stated, we believe our pivotal study patient population is the most challenging composition of WM patients ever evaluated in a clinical study.
As reported, CLOVER-WaM represents, as far as we are aware, the largest study to date in relapsed or refractory WM patients, post-BTKi therapy and the most refractory WM population ever tested in a clinical study. This assessment was agreed upon by top WM thought leadership at a recent advisory board commenced to review the CLOVER-WaM top-line data. Patients received a median of four prior lines of therapy, with a range of two through 14.
90% were refractory to either a BTKi or a CD20 antibody. 50% were refractory to BTKis, 40% were refractory to rituximab, and 27% were dual-class refractory to BTKi and CD20 antibodies. In addition, approximately 30% represented MYD88 wild type, a genotype with a high resistance profile to BTKis.
Despite this extremely challenging patient population, iopofosine I 131 achieved a 75.6% overall response rate and a 61% major response rate, which clearly exceeded the study's major response rate, statistical significance hurdle, and primary endpoint of 20%. In addition, 100% of evaluable patients achieved disease control, experiencing a meaningful reduction in baseline IgM.
Based on the biological nature of WM, iopofosine I 131's mechanism of action and demonstrated CLOVER-WaM efficacy results, we may see further improvement in the major response rate as well as the depth of these responses. To elaborate, patients experienced improved results over time. In fact, there was more than a 2x increase in the major response rates for the first 25 patients, with additional follow-up between 3 and 6 months, with 18 out of the 25 patients, or 72%, achieving a major response.
With at least 55% of the WM population being treated in the community setting, predominantly in highly organized, integrated delivery networks such as Texas Oncology, we determined that it would be helpful to provide access to additional insights from the community treatment perspective versus the academic setting.
To this end, we appreciate Dr. Levy's willingness to further review iopofosine's positive pivotal data and provide his perspective on his potential role in the treatment of WM patients in the community. Prior to Dr. Levy's review, Shane Lea, our Chief Commercial Officer, will provide a brief WM market assessment.
Our COO, Jarrod Longcor, will discuss the next steps in the regulatory process and our commercial readiness for our manufacturing and distribution network. Dr. Andrei Shustov, our Senior Vice President and Medical Lead, will introduce Dr. Levy. I will now transition to Shane Lea for his overview of the WM landscape and patient journey. Shane?
Thank you, Jim. The iopofosine positive top-line results from the CLOVER-WaM pivotal study was prominently featured in more than 20 publications.... This includes coverage in major oncology and life sciences outlets, including Targeted Oncology, Cancer Network, OncLive, Cure and Scrip, which helped to optimize awareness for iopofosine's impressive data in WM. The top line data was also highly regarded by WM experts based on the impressive responses demonstrated in a heavily pre-treated population.
As previously stated, we believe these data highlight the unique benefits iopofosine provides for patients. In fact, our physician market research clearly identifies the need for a new mechanism of action, a fixed course of therapy, and improved efficacy as the most desired product attributes for the management of WM patients.
We are confident that iopofosine can address these desired attributes with a potential FDA approval in relapsed or refractory WM by delivering a much-needed new mechanism of action, demonstrating breadth of patient responses, deep, durable responses, and a short, fixed course of therapy. Importantly, physicians who participated in this study were able to appreciate these key attributes and the associated impact in a heavily pre-treated patient population. There are approximately 26,000 patients living with WM in the United States.
Approximately 10,000 plus are relapsed or refractory, and 4,300 patients represent the third line and beyond. The annual third-line incidence is nearly 1,000 patients, and 55% of all prevalent patients are managed in the community setting. There is no current standard of care in the relapsed refractory setting. Therefore, patients have limited treatment options comprised of unapproved therapies.
Consequently, our market research shows that many patients are treated with the same class of drugs across multiple lines of therapy. This likely means patients are required to be on continuous therapy, must take additional visits to the clinic, either for treatment, blood draws, or monitoring management of drug adverse events. This creates complex treatment challenges and financial burden for patients. Predominantly because of the limited treatment options, there are approximately 1,000 third-line patients currently not receiving any therapy who are eligible for treatment.
To date, there is no published study in a late line or dual refractory to both BTKIs and anti-CD20 antibodies. A review of real-world clinical data beyond second-line treatment in the community indicates a major response rate range of 4%-12%, which highlights the need for new therapies that provide better responses for patients.
We believe iopofosine has the potential to become a new standard of care. We continue to advance our commercial strategy for iopofosine to ensure a successful launch, assuming FDA approval. Our data supports the concentrated and highly scalable nature of the WM market in the US In fact, approximately 80% of WM patients reside within 15 states, and 70% of patients are treated within 10% of all accounts. This patient concentration supports a targeted and efficient resource allocation to drive iopofosine use and adoption and capture the WM opportunity.
To this end, our plans include establishing collaborations with large oncology community networks. We recently announced our collaboration with the American Oncology Network, in addition to our previously announced partnership with Florida Cancer Specialists. These two organizations alone combine to treat nearly 2,000 WM patients.
We look forward to highlighting additional details regarding our commercialization readiness and overall progress as we advance our strategic plan. I will now turn the call over to Jarrod Longcor to highlight our production capabilities and regulatory pathway. Jarrod?
Thank you, Shane. As many of you know, radiotherapeutic manufacturing that provides a consistent, uninterrupted supply of targeted radiotherapeutics has proven to be challenging. For this reason, we determined that a different strategic approach to solve the issue was required.
Unlike other radiopharmaceutical drug companies, we have developed and refined our manufacturing supply chain and logistics network to provide seamless and secure access to iopofosine without the $10s of millions of dollars of required investment for infrastructure, along with the associated financial burden of maintaining those facilities. We have established a multi-source supply chain network that allows overlapping redundancy from our selected CDMOs, from isotope to finished product.
These strategies allow us to provide secure global supply with secondary supply optionality in the event of a condition impacting one of our contractors. In addition to this approach, providing the comfort of delivering required patient doses as planned, we have also created an extended treatment window for both patient and physician convenience. For any number of reasons, patients or physicians may be required to reschedule the planned treatment, delaying dosing for a number of days. For most radiotherapies, a delay would require a new dose to be provided, creating a significant treatment delay.
In the case of iopofosine I 131, our proprietary drug formulation creates the first-ever, essentially off-the-shelf product with potentially radiopharmaceutical industry-leading 17+ day shelf life. This provides dosing flexibility that is currently not available with targeted radiotherapies. Additionally, iopofosine is shipped and stored at room temperature as a fully finished, ready-to-use product that arrives at the treatment center with no on-site compounding required.
Our distribution logistics and are designed to ensure transport and arrival to all treatment centers in under 72 hours, anywhere in the world. This feature will allow clinical centers to have at least 14 days to schedule and the flexibility to reschedule the patient's treatment if needed. With a robust manufacturing and supply chain established, our near-term goal is to continue to closely collaborate with the FDA and EMA to bring iopofosine to WM patients in both the United States and Europe as rapidly as possible.
To that end, we plan to complete our NDA filing and submit to the FDA for approval in the second half of this year, and in parallel, leverage our prime designation work with the EMA, or EMA, to bring iopofosine to Europe as soon as possible.
Based on iopofosine WM Fast Track and Orphan Drug designations, we have engaged the FDA in regular discussions that have provided clear and helpful guidance on information and requirements necessary for the submission. We have been very pleased with the nature of these discussions and the ongoing collaboration with the agency and are working diligently to ensure our submission for iopofosine addresses all agencies' requested elements.
Assuming the priority review associated with the Fast Track designation is accepted, we would expect an approximate 6-month review period from the date of submission for our NDA. With that, I will now turn the call over to Dr. Shustov. Andrei?
Thank you, Jarrod. As my colleagues already stated, we're very excited with top-line results from our CLOVER-WaM study. The efficacy and safety profile of iopofosine I 131 in a heavily pretreated elderly patient population with highly refractory disease are impressive and possibly treatment paradigm shifting. Beyond 2 lines of therapy, treatment options and their clinical benefits are limited.
In addition, current treatment approaches commit most WM patients to long-term or continuous therapy to maintain disease control without meaningful disease-modifying effect and perpetual toxicity with no or very limited treatment-free intervals. We believe that iopofosine's limited duration therapy, favorable toxicity profile, meaningful durability of response, and prolonged freedom from therapy may provide a novel treatment option to patients in high need. As Shane mentioned earlier, over half of all prevalent WM patients are managed in a community setting.
Therefore, to appreciate the community physician's perspective and reaction to CLOVER-WaM results, it is my great pleasure to introduce Dr. Yair Levy from Texas Oncology, one of the largest community cancer care organizations in the US Dr. Levy possesses a unique background with experience in both the community and academic setting. He's a hematologic oncologist with over 15 years of community oncology experience.
He's also an associate professor of medicine at Texas A&M HSC College of Medicine and Director of Hematologic Malignancies Research at Baylor University Medical Center in Dallas, Texas, and is an author on over 50 publications in the field of hematologic malignancies. He obtained his medical degree from the University of Wisconsin and completed oncology fellowship at Johns Hopkins University.
Dr. Levy practices at Texas Oncology with his primary office in Dallas, Texas. Texas Oncology encompasses over 280 locations in the state, with approximately 1,200 WM patients currently under care. Dr. Levy?
Thank you, Andrei, and thanks to the team for inviting me to participate in this call. Let me start with a review of the study design and patient enrollment criteria before moving to a review of the top-line results. So the CLOVER-WaM pivotal trial is a global, open-label, single-arm study examining iopofosine I 131 in relapsed and refractory Waldenström's macroglobulinemia patients who require therapy due to symptomatic disease progression.
Patients enrolled in the trial had to have histologically and serologically confirmed Waldenström's macroglobulinemia, an ECOG performance status of zero, one, or two, and have received at least two prior lines of a standard of care therapy, including a Bruton's tyrosine kinase inhibitor. Note that the study also included Waldenström's patients with central nervous system involvement, also known as Bing-Neel syndrome, given the ability of iopofosine I 131 to cross the blood-brain barrier.
Additionally, included were patients with lymphoplasmacytic lymphoma, establishing CLOVER-WaM as the first study to address these high-need populations. Patients were dosed in two cycles, the first cycle occurring on day 1 and day 15, and the second cycles on day 57 and day 71 from the study entry, respectively. The primary endpoint of the trial was a major response rate, which is defined as a partial response or better.
A partial response is defined as a 50% or more reduction in the disease biological marker, which is IgM. Key secondary endpoints included the duration of response, progression-free survival, and treatment-free survival.
The study protocol target is 50 patients in the modified intent-to-treat population, and top-line data was reported on 41 evaluable patients meeting protocol criteria for efficacy assessment at the data cutoff date of January 3, 2024, and having sufficient follow-up after the last administered dose to enable the development of therapeutic effect. Median age was 71 years old, with the oldest enrolled patient 88 years old, and patients in the trial received a median of 4 prior lines of therapy. This is now 5th-line therapy, with a range of from 2-14 prior lines.
Nearly 90% of the evaluable patients were refractory to either rituximab or a Bruton's tyrosine kinase inhibitor. 27% were dual-class refractory to both a CD20 monoclonal antibody as well as a Bruton's tyrosine kinase inhibitor.
80% of patients were previously treated with a Bruton's tyrosine kinase inhibitor, of whom 50% were refractory to the BTKi. 91% of patients were exposed to rituximab, of whom 40% were refractory. This represents the most refractory Waldenström's macroglobulinemia patient population reported in clinical trials.
Let me also note that nearly half of the patients in the CLOVER-WaM study were considered either moderate or high risk based on IPSS-WM Waldenström's macroglobulinemia score, which is a recognized negative prognostic factor for both progression-free and overall survival in Waldenström's macroglobulinemia. Furthermore, nearly 30% of study patients were found to have a wild-type MYD88 gene, which is a known genomic factor conferring less response to Bruton's tyrosine kinase inhibitor therapy.
So the study achieved its primary endpoint with a major response rate of 61%, with that 95% confidence interval ranging from 44% to 75%. The overall response rate was 75.6%, and disease control rate was 100%. It's important to point out that attainment of complete remission, complete response in 8% of patients is impressive and is rarely reported in relapsed and refractory Waldenström's macroglobulinemia with any patients.
So the review of individual responses is very instructive and provides further details of iopofosine I 131 potent activity in this patient population. First, the attainment of a complete remission in 3 patients is very impressive and rarely, if ever, reported in trials of patients with relapsed or refractory Waldenström's macroglobulinemia.
You'll note that three additional patients achieved a very good partial remission or near complete remission, and with additional follow-up time, might improve their responses from a VGPR to a CR, therefore increasing the CR rate. Every individual bar is facing down on this waterfall plot, indicating tumor volume reduction and disease control rate of 100% in this patient population.
Based on the biology of Waldenström's macroglobulinemia, iopofosine I 131 mechanism of action, and the current CLOVER-WaM efficacy results, we expect to see further improvement in the major response rate, as well as the depth of these responses. To elaborate, among the first 25 consecutively enrolled patients in the study, the major response rates at three and six months were 28% and 72%, respectively. This is a 2.6 time increase in these response rates with additional follow-up after completion of therapy.
The corresponding overall response rate at 3 and 6 months were 64% and 88%, respectively, a 37% relative increase with additional follow-up, but not additional treatment. So the Kaplan-Meier analysis utilized 30 evaluable patients with responses, and responses were durable, with a median duration of response not yet reached at a median follow-up of 8 months, with maximum ongoing responses continuing beyond 30 months.
The confidence interval predicts for a median duration of response of no less than 11.4 months in these multiclass refractory patients. So iopofosine I 131 was well tolerated, with a safety profile consistent with previously reported data.
As anticipated, in heavily pretreated elderly population, the most common treatment-related adverse events of grade 3 or higher that occurred in more than 10% of patients were hematologic in nature and included thrombocytopenia in 55%, neutropenia in 37%, and anemia in 26%. These cytopenias were predictable, manageable, and all of the patients recovered from treatment-emergent cytopenias.
Importantly, there were no treatment discontinuations due to drug-related AEs. There were no treatment-related deaths, and there were no clinically significant or life-threatening bleeding events. So in summary, iopofosine I 131 demonstrated an impressive and potent activity in a highly refractory, heavily pretreated patient population and possesses an ability to become a paradigm-shifting treatment options for these patients with a high unmet need for novel therapies.
Notably, the duration of response currently demonstrated in the CLOVER-WaM study is approximately double of what we would have expected in patients with a similar profile. Based on available data, the responses are likely to improve over time in terms of the rate and depth of responses. The attainment and maintenance of complete remissions or complete responses after completion of therapy in this patient population is unprecedented and speaks towards the disease-modifying quality of iopofosine...
Additionally, the safety profile was quite impressive for both the age of the patients enrolled and the amount of prior therapies that they have also received. I would have expected more adverse events and more grade three plus cytopenias if I were giving these patients any of the non-approved salvage therapies that are currently available in this disease state to them. I'll conclude with this.
From the perspective of community oncology physicians, I would particularly emphasize the key advantages of iopofosine for Waldenström's macroglobulinemia patients, for which the overwhelming majority of them are elderly. Based on the experience of our practice, iopofosine is easy to handle and administer. The extended half-life allows for scheduling flexibility and extra accommodations for patients and physicians and needs in terms of scheduling. Even patients who live many miles away from treatment centers and who are at risk for travel delays and cancellations are not at risk of missing doses.
Patients particularly appreciated the limited and fixed duration of therapy, resulting in a positive impact of quality of life. Patients and physicians truly appreciate having effective treatment options with a novel and unique mechanism of action.
There's truly a paradigm shift from just, "keeping disease stable or under control with continuous therapy" to disease-modifying agents that have limited duration of therapy and a long time off of therapy without disease progressing. There's also an additional benefit of not having required dosimetry. There's no need for specific inpatient isolation compared to earlier generations of radiotherapeutics. Having said all that, it's now my pleasure to return the call to Jim Caruso.
Thank you, Dr. Levy. Let's now transition to the Q&A portion of today's program. Operator?
Thank you. Ladies and gentlemen, we will now begin the question and answer session. Should you have a question, please press the star followed by the one on your touchtone phone. You will hear a three-tone prompt acknowledging your request. If you would like to withdraw your question, you may do so by pressing star followed by the two. Once again, to register for a question, please press the star followed by the one on your telephone keypad. One moment for the first question. Our first question comes from Jonathan Aschoff from Roth MKM. Please go ahead. Your line is open.
Thanks, and good morning. You know, what is your... What are the drugs used in the continuous drug regimen for these refractory patients? You know, would you just necessarily switch them right over from that continuous therapy to 131, or would you need, you know, some specific reason to do that?
Good morning. Good morning, Jonathan. Thank you for your question. Much appreciated. We'll transition over to Dr. Levy to manage that. Thank you.
No, absolutely. So in terms of a continuous treatment paradigm, the one that is most frequently used and used per the FDA label, is in the class of drugs called Bruton's tyrosine kinase inhibitors, for which there are currently two drugs approved. The first one was a drug called ibrutinib, or IMBRUVICA, that was approved either as a monotherapy or in combination with a CD20 monoclonal antibody. And, you know, these drugs are typically given until.
And the second one, of course, is zanubrutinib or BRUKINSA, and these drugs are typically given until progression or intolerance. So as long as we're seeing that they're receiving, you know, clinical therapeutic benefit from getting the drug and they're tolerating the drug, these drugs are continued.
Now, in terms of another drug that can be used in a continuous modality, the other one that we sometimes use is a drug called venetoclax, but that is an off-label use of a drug and certainly is not seen being used very much, you know, in the management of this disease. And, you know, while you certainly could, you know, stop the therapy and switch over to iopofosine, most physicians, you know, as long as somebody is responding and tolerating a Bruton's tyrosine kinase inhibitor, would actually keep that therapy going.
Okay, you know, regarding liquid tumor patients outside of WM, do you believe that the existing data, you know, particularly outside of this data set, you know, support iopofosine use in other cancers? And if yes, which liquid tumors?
Well, so I mean, again, you know, certainly there is, you know, a lot of preclinical and also some clinical rationale for the use in other disease. And, you know, this is certainly a very intriguing platform, in terms of, of therapeutic delivery. But, you know, I think that most of the data that we have is in Waldenström's. So I can certainly say that I'd be very encouraged about this, this particular platform and delivery model for use in other cancers as well. But I think the most robust data that we have currently is in Waldenström's. This is a, a very nice proof of concept for this delivery vehicle.
Yes.
Thank you.
Thank you, Dr. Levy. Why don't we have Andrei, would you like to provide some further clarity about our thoughts relative to our existing data sets beyond WM and perhaps some, you know, future, future perspective on the potential clinical development of the asset?
Sure. Thank you, Jim, and thank you for your question. As stated just a minute ago, our most advanced data naturally is in Waldenström's macroglobulinemia with recently released results. Having said that, as we previously reported, CLOVER-WaM study has emerged from a broader basket trial or a phase IIa study that enrolled patients with numerous ... lymphoid malignancies and plasma cell malignancies, including multiple myeloma and variety of non-Hodgkin lymphomas.
We have previously reported our activity in highly refractory multiple myeloma, including BCL and post-BCMA therapy, are very impressive, as well as results in non-Hodgkin lymphoma, including those with central nervous system involvement. So if you think about the broad, if not uniform, distribution of the target for our platform, lipid rafts, we can virtually target any tumor because it's a very basic mechanism for tumor survival, and then pair this with a specific payload.
So our programs that are currently running are those again in additional varieties of non-Hodgkin lymphomas, multiple myeloma, and it certainly makes sense to target diseases related to WM or indolent lymphomas, such as, say, marginal zone, mantle cell, and potentially others. We have really high interest in advancing and expanding iopofosine I 131 use in hematologic malignancies, and we'll be proceeding in that direction.
Thank you for that. My last question is more for management. What price do you think the US market would support for this drug? Are you seeking an E.U. partner, and have you received the $44 million?
It sounds like there was... the last question included three separate questions, Jonathan. Very clever. Why don't we have, Shane address, your question relative to general thoughts relative to the pricing piece?
Yeah, I think... Thank you, Jonathan, for the question. A very, very good question. Very important question. I think as, as we're, you know, continuing to evaluate the market opportunity, certainly, looking at the capabilities that iopofosine provides and understanding the dynamics of the market from a value perspective, especially related to other products and continuous therapies, total cost of therapies with some of these continuous products could, could be as high as $1 million.
Obviously, we, we believe that with iopofosine's profile, we have the opportunity here for orphan drug pricing. But we're going to continue to do the research on our end to ensure that we're providing the right price, the right value, based on, you know, the novel mechanism of action and the ability to address unmet need in this high-unmet market.
All right, then we'll have Jarrod address our ex US co-promotion thinking.
Yes, thank you. Again, thank you, Jonathan, for giving us all a chance to answer your question. So yeah, we are engaged in a number of dialogues for, as Jim alluded to, ex-US co-promotion or promotion collaboration. As it currently sits and as you, as Shane just alluded to, obviously in the US, we're looking to promote this on our own, but ex-US, we are in deep discussions with various partners for different territorial control.
And then relative to the Tranche A $44 million, the conversions are ongoing, and we fully expect, you know, to secure the entire $44 million, no later than Tuesday of next week. They are ongoing. Obviously, I will make this comment regardless of the external constituent, the data has been viewed very, very positively.
Thank you very much, guys.
Thank you, Jonathan.
Thank you. Our next question comes from Jeff Jones from Oppenheimer. Please go ahead. Your line is open.
Good morning, guys, and thanks for taking the question. A couple of them, not surprisingly. I guess, first off, to Dr. Levy, can you speak to some of the logistics of implementing a product like this in your practice of a targeted radiopharmaceuticals using I-131? Things like the license, disposal, shielding, you know, the level of complexity of implementing that in practice, and some of the key barriers.
No, absolutely. So I think that's a wonderful question, especially given the previous history of, you know, Zevalin and Bexxar in the hematologic, you know, treatment realm for radiotherapeutics. But, you know, I should say that there are several, obviously, key differences. So, you know, those two products that I previously mentioned were ones that were, you know, approved in indolent non-Hodgkin lymphomas and did not get much uptake from the market, despite, you know, reasonable efficacy.
And, you know, one of the main reasons is we did have other therapeutic alternatives that medical oncologists were able to use. And, you know, here in, especially in, in these patients that we treated with Waldenström's on this study, there were no other readily available, you know, therapeutic options, and certainly not ones with anywhere near the efficacy that we have seen so far in this study.
Now, in terms of logistics, so this drug does require, you know, either nuclear medicine or radiation oncology for administration, but there are, currently a lot of products on the market that utilize this, radioactive payload. So this is not a payload that physicians are uncomfortable with. Furthermore, you know, just about every medical oncologist, you know, in the United States has a working relationship with radiation oncology, as oftentimes, you know, dual treatment modalities are required in the treatment of various malignancies.
So I can tell you that in our own experience, the logistics have not been difficult at all and actually quite favored by patients. And, you know, we had this trial open here in Dallas, and Texas Oncology is obviously a very large network of physicians that, you know, that encompass the whole great state of Texas. And as you know, Texas is a pretty big state with two time zones. So we were able to even get patients from as far as El Paso to come, and they stayed, you know, locally while they were receiving their treatment, and then were actually able to go back to their referring physicians.
So, you know, obviously with commercial approval of the product, this can be given by, you know, almost every, you know, nuclear medicine or radiation oncologist in the country and certainly would not require somebody traveling such a distance. But, you know, even if that was required, it was still logistically very easy and feasible to do.
And I think the other, you know, really neat aspect of this therapeutic is not just the fixed duration of therapy, which obviously patients and payers both favor. You know, patients favor it because of time off therapy, and time off therapy allows you to get back to, you know, what we call a more normal existence.
Obviously payers like fixed duration of therapy because it limits their exposure to, you know, additional costs of therapeutics, and costs of therapeutics usually tend to be lower for fixed duration of therapy as opposed to indefinite therapy. But, you know, the side effect profile in our experience was also quite good with, you know, patients having predictable and delayed cytopenias, meaning lower blood counts.
But if you take a look also at physician comfort with adverse reactions as well as patient comfort with adverse reactions, physicians are very comfortable managing cytopenias, and patients usually do not feel bad with cytopenias. It just sometimes requires transfusional support, you know, and/or what's called growth factor support, so medicines to help make the counts come back faster. You know, if their white count comes low, we also sometimes will place them on some antibiotics to try to prevent infections as well. But, you know, logistically, this has been a very easy therapeutic to give.
Really appreciate that detail. Thank you. Could you, you know, speak a little more to the issue of BTKi tolerability, and what might impact sort of patient decision-making between the transition from a BTKi to a, to iopofosine?
Absolutely. So, I mean, so first of all, we should say that not every patient will do well with Bruton's tyrosine kinase inhibition. They've certainly been a godsend in this disease because, again, it's an effective, well-tolerated therapy for most, but not for all. And, you know, the issue is, you know, what do you do when somebody progresses? Because it's clearly not curative therapy.
So it's not only that we'll have people, you know, switch from a Bruton's tyrosine kinase inhibitor because of progression, but sometimes they'll also switch for intolerance. Remember, these are drugs that you're taking indefinitely for a prolonged period of time.
Despite the fact that these, you know, drugs are so much better tolerated than traditional cytotoxic chemotherapy, there are sometimes these nagging adverse reactions that can occur, you know, with the drug, both in the short and the long term.
Okay. How long do patients, in your experience, typically stay on BTKIs? And then what portion, I guess, become BTKI refractory?
So that's a great question. So, you know, the patients stay on for years. You know, there's obviously great variability. There's some patients who don't respond very well, and there's some patients who can have a very deep response. Now, complete responses with a Bruton's tyrosine kinase inhibitor are exquisitely rare, but people can, you know, still have a very prolonged duration of response. But remember, this is duration of response with continuous therapy.
So this is not, you know, we give a fixed duration, and then we, you know, have a treatment-free period in which we wait and see what happens with the disease, because when we stop the Bruton's tyrosine kinase inhibition, then typically the disease progresses quite rapidly. But like I said-
Okay.
Most folks can stay on for years at a time, with Bruton's tyrosine kinase inhibition, but it is not curative therapy. So eventually somebody will require something else.
Okay, great. I guess probably a question for management. You spoke to the issue of, or the potential for deepening responses over time. And I know you're fully enrolled, but only 41 patients at this point eligible for evaluation of responses. In looking at that waterfall plot, can you speak to the number of patients that are, you know, proportionally only at that, say, 3-month time point in evaluation?
Fair, fair question, Jeff. We'll have Andrei address that.
Yeah, thank you, Jeff, and thank you, Jeff. Very important question, and I will point out again that we, when we saw this, correlation between longer follow-up and deepening of responses, we certainly were very excited to appreciate that because with many patients in the study enrolled in last quarter of last year, we certainly hope that with longer follow-up of therapy, after they completed therapy, we will see deepening of those responses and potentially even more exciting results that we could report with data maturation.
If you look at the waterfall plot, it certainly correlates with numbers that all of us mentioned, with 25 patients who were treated early in the study and had significant improvement in the response. The patients on the left side of that bar graph or waterfall plot, those you can even count those bars, and it almost correlates precisely with 18 patients who had follow-up much shorter than six months. So, we have a pretty high level of confidence that even with patients already shown on that waterfall plot, that we should see improvement in depth of response and potentially numerically.
All right.
Thank you, Andrei. That was, that was very helpful. I think, you know, specifically, the remaining patients, Jeff, are, are likely in that kind of 2-4-month window, as we, as we currently said.
Okay, so there's also additional patients that were dosed more recently, given 41 are... only 41 are evaluable for response. So I guess, when would we be looking for the next update on additional patients and also deepening of responses?
I mean, when you think about the definition for the MITT in those patients that were evaluable for efficacy, it was 6. Just to put it in perspective so you have a sense of the timing, it was 60 days post their last dose, you know, so that.
And then as we, as Andrei pointed out, many patients of the remaining, you know, between the 41 and the target evaluable of 50-ish, were in the last quarter of last year, which is why we kind of sit for many of them in this kind of 2-4-month area as they advance through the, you know, as we've coined it, the conversion zone. And so I think you can do the math on that, Jeff. When, with the majority of patients in the 2-4 month range, then you can do the back end of the evaluable 60 days post the second dose.
Okay. When are you thinking about timing for providing another update in terms of progression of these patient populations?
Very clever follow-up question, Jeff. You know, I think the April, May-ish timeframe may be, may be reasonable. And, you know, we would be careful in terms of what we do update, right? So we can give you the same type of data that we already provided, updated, and we do want to save, you know, many of the important cuts of the data and really interesting, you know, segmented clinical data, for, you know, peer review journals and obviously a presentation at a major event toward the back end of the year.
Great. Thank you, guys, very much.
Thank you, Jeff.
Thank you. As a reminder to register for a question, please press the star followed by the one on your touchtone phone. Our next question comes from Ahu Demir from Ladenburg. Please go ahead. Your line is open.
Good morning, everyone. First of all, I would like to congratulate the team again in front of the public, so congrats on the data. I have a couple of questions to Dr. Levy, then to the management. Dr. Levy, I was curious. I know you commented on the safety profile, but just curious if you could elaborate more on that side, how it compares to the currently used medicines.
And the second part of my question is: what are your thoughts on using iopofosine in the front line, and what do you think about the changing doses? Do you have some potential to do that? So just curious about your thoughts on that, given your experience with the WM patients.
Yeah. So, so your first question was about side effect profile, and in terms of side effect profile, like I said, it's, it's been... All, all we have seen is cytopenias, meaning, you know, red count, platelet count, and white blood cell count go down. And like I said, it's typically more delayed than we see in chemotherapy.
So, you know, for a lot of chemotherapy regimens that we give, the counts will probably go down, you know, about a week, a week and a half after, and here it can be a month after. You know, it's, it's, it's rather predictable and, you know, can respond to supportive care quite nicely and recovers, right? And that's the most important thing, that it recovers.
And remember, we were also treating these heavily pretreated patients who were on average older and therefore have less than what we in what we call marrow reserve, meaning that, you know, they don't have as much fitness to their bone marrow, so they don't necessarily bounce back quite as quickly from therapies. But, you know, everybody seemed to bounce back quite nicely on this study. And your second question, I think, was asking about frontline use, and, you know, I'm going to give you the answer that a physician always gives, is we'd have to see a study, right?
And we'd have to see a study with comparison of, you know, how something compares in the front line to later lines of therapy and obviously compare, you know, the pros and the cons of each therapy. So I don't know. I mean, you know, I, I don't know that I can say, you know, we should use this or not use this because we just don't have data in the front line. And your third question, again, was? I'm sorry, I forgot.
It was about the. No, no worries. It was about the dosing flexibility. Is there any way that you would use lower dose in the frontline? But I think you answered my question.
Yeah. So, I mean, again, yeah, we'd have to have a study looking at it. You know, another question I think would be very fair to ask is, you know, would there be a benefit in giving a, you know, a third follow-up dose to people who are responding? And, you know, again, this would all have to be sorted out in another trial. But, you know, we can certainly just comment on the dosing schedule that was done in this study, right? And we can say that that certainly proved itself to be safe and effective.
But, you know, would alternative dosing strategies potentially work better for some folks? And, you know, would potential earlier lines of therapy work better for some folks? You know, it's certainly a possibility, but we would require trials in order to answer that question.
My other question is to the management. You commented on the European partnership or approval efforts. Curious if you are planning to pursue outside of US and Europe, and would it be more in line with partnership, or are you going to pursue yourselves?
Nope, great question. First of all, thank you for being on the call. Thank you for your questions and your support as always, much appreciated. Clearly, in the US, as Shane mentioned, because of the highly scalable nature of the WM patient population, you know, we're confident in our capacity with a very highly efficient, targeted commercial organization, we could be very successful in terms of driving top line utilization, you know, share and adoption in this space. Ex-US, clearly we do not have the capacity nor the interest in building out an infrastructure to successfully drive commercialization there.
However, we've made significant progress, and one of the benefits is the PRIME designation we received from the EMA. Jarrod Longcor has been driving all of our discussions, both aided and unaided, relative to, you know, how we think through ex-US commercialization. We have a number of different options, and I'll have him share his thoughts.
Yeah, I hope. I would say we are looking at, as you might expect, for essentially global approval, and as broadly as we can get in various territories. There will be some territories that may prove a little bit more challenging. But, you know, when you think of it, it... we're looking at Europe, Asia, South America, Australia, you know, obviously, Central Latin America and sort of the MENA states.
So, and for anything, as we mentioned, anything outside the US, we are in dialogue with various potential partners to sort of bring them on board in parallel with our approval, packaging, and everything else in those various territories.
And the only other thing I would add to that is all of our contracts relative to ex-US co-promotion, you know, we would have the capacity to claw back as needed with a slight premium. But all of our contracts will include our capacity as a company to claw those contracts back, and for a very limited premium.
Understood. And my last question would be, what are your plans to, for commercial efforts? What are we going to see in the next 6-12 months of timeline?
Great question. Thank you. I'll turn it over to Shane Lea.
Yeah, thanks for the question. As Jim pointed out, and as we've stated previously, this is a concentrated market. It's highly scalable, so that's very advantageous for us. And so, you know, the key step here is to ensure that we're building the right type of data capabilities internally so that we can be very pointed and focused in our commercialization efforts. That will drive our resource allocation.
And so, you know, the next 6-12 months will be really focused on ensuring that we're building the right capabilities and ensuring that we're bringing in the right type of talent and gating it properly so that we can, you know, maximize our launch efforts and ensure that, you know, we're capturing the opportunity the best that we can.
So, it will be highly integrated, highly customer focused. We want to make sure that we're going to drive, as the best we can, awareness for the product, and, more importantly, ensure that the first experience is the right and best experience, when customers reach for iopofosine.
Great. Thank you so much for taking my questions.
Of course. Thank you.
Thank you. There are no further questions. I'll return the conference back to Jim for closing remarks.
Terrific. Thank you, operator. This concludes today's program. Certainly, on behalf of the company, I would like to share our gratitude for Dr. Levy's participation and, of course, thank the audience, as always, for tuning in and for the quality questions. Please have a great day. Thank you.
Thank you, ladies and gentlemen. This concludes your conference call for today. We thank you for your participation and ask you to please disconnect your lines.