Ladies and gentlemen, thank you for standing by. Geron Corporation fourth quarter fiscal 2021 earnings call. All lines have been placed on mute. The speaker's remarks will be followed by a question and answer session. If you would like to press star followed by the number one on your telephone keypad. If you would like to withdraw your question, again, press star one. Thank you. Olivia Bloom, you may begin your conference.
Good afternoon, everyone. Welcome to the Geron Corporation fourth quarter and year-end 2021 conference call. I'm Olivia Bloom, Geron's Chief Financial Officer. I'm joined today by Dr. John Scarlett, Geron's Chairman and Chief Executive Officer, Dr. Aleksandra Rizo, Geron's Executive Vice President and Chief Medical Officer, and Anil Kapur, Geron's Executive Vice President of Corporate Strategy and Chief Commercial Officer. Before we begin, please note that during the course of this presentation and question and answer session, we will be making forward-looking statements regarding future events, performance, plans, expectations, and other projections, including those relating to the therapeutic potential and potential regulatory approval of imetelstat, anticipated clinical and commercial events and related timelines, resources, and other statements that are not historical facts. Actual results and events could differ materially.
Therefore, I refer you to the discussion under the heading Risk Factors in Geron's annual report on Form 10-K for the year ended December 31, 2021, which identifies important factors that could cause actual results to differ materially from those contained in the forward-looking statements. Geron undertakes no duty or obligation to update our forward-looking statements. Now I will turn the call over to Dr. Scarlett. Chip.
Thanks, Olivia. Good afternoon, everyone. Before reviewing our significant accomplishments of 2021, and even before discussing how we plan to build on those accomplishments in 2022 and beyond, I'd like to spend a moment putting into context why we believe imetelstat can potentially be such a transformative drug, especially in the treatment of hematologic malignancies. Next slide, please. As many of you know, telomerase is an enzyme that adds length to the ends of chromosomes, thus allowing for continued cell proliferation. This enzyme is transiently expressed in normal hematopoietic stem cells during blood cell production. In contrast, telomerase is continuously expressed in malignant hematopoietic stem and progenitor cells, leading to their uncontrolled proliferation. imetelstat is an oligonucleotide discovered and developed by Geron that inhibits telomerase and limits the proliferation of malignant cells where telomerase is continuously expressed, those malignant cells. This mechanism of action is unique and first-in-class.
What makes this drug so exciting and a very substantial potential value is that IMpactMF data provides strong evidence of disease-modifying activity. Next slide, please. Here we summarize that key evidence. Target engagement of telomerase and depletion of malignant stem and progenitor cells in the bone marrow is evidenced by elimination of the malignant cells marked by molecular and cytogenetic abnormalities. Importantly, in our phase II trials, the reduction in telomerase activity and depletion is clinically meaningful through the correlations of those biologic effects with clinical benefits such as anemia responses in MDS and in MF, reduction in bone marrow fibrosis as well. These data, which provide strong evidence of disease-modifying activity, which we expect will allow imetelstat to significantly advance patient care in MF. Now let's talk about what happened in 2020.
A critical focus in 2021 involved advancing our two ongoing phase III trials toward important readouts. These trials are designed to address high unmet medical needs in lower-risk MDS and refractory MF and are intended to be registration-enabling trials in those indications. In our IMerge phase III trial in lower-risk MDS in October 2021, that milestone achievement enables topline results for the key efficacy and safety parameters, what we call TLR. Topline results confirm the similar safety as well as quality of transfusion independence that was observed in our phase II trial in the same lower-risk MDS patient population. We expect to submit an NDA for lower-risk MDS within the first half of 2023. Assuming approval, we expect imetelstat to be commercialized as early as the first half of 2024.
I can't wait to get to TLR and see those data, and the next 10 months cannot come fast enough. In 2021, we also made progress in our second phase III trial, IMpactMF, with 50% of the sites being open for enrollment. We also started several new programs with high strategic value and only modest initial costs that are designed to broaden imetelstat's potential use in additional indications and combination regimens. Aleksandra will provide more detail on IMpactMF and the rest of the imetelstat clinical development. Finally, in 2021, we began the process of transforming Geron into a commercial stage company. We're doing this by utilizing a. We've already engaged in preparation of long lead time items for our first NDA, such as validating manufacturers and are beginning for the imetelstat NDA.
We also began hiring key executives in areas needed to support commercial, medical affairs, market access and a Chief Business Officer. Many of our internal activities are focused on keeping to aggressive timelines for submission of an NDA in the U.S. and ultimately an MAA in Europe, assuming the TLR data supports such submissions. Both the lower-risk MDS program and the refractory MF, two indications, assuming regulatory approval and launch in the U.S. and EU five countries have the potential to generate annual peak revenue of greater than $3 billion in 2030. As a result and in parallel with our continuing preparations to commercialize imetelstat, we're actively investigating potential relationships with appropriate partners. These include exploration of regional and other deal structures of possible mutual interest, which could potentially further accelerate imetelstat development and commercialization.
I'd like to hand the call over now to our Chief Medical Officer, Aleksandra Rizo. Aleksandra will provide you with an update of our clinical efforts. Following that, our Chief Commercial Officer and Head of Corporate Strategy, Anil Kapur, will share with you his synthesis of the expected differentiated role of imetelstat in both lower-risk MDS and refractory MF. Before I make some final comments at the end of the call, our Chief Financial Officer will review our fourth quarter and year-end 2021 results and provide financial guidance for 2022-
In 2021, our clinical focus was on advancing our two phase III trials in lower-risk MDS and refractory MF. This focus will continue in 2022 phase III trial and complete opening sites for the IMpactMF trial this year. The clinical team will concentrate on executing activities such as data cleaning to enable timely database locks and ensure top-line results are reportable in 2023. Given the number of patients and clinical sites around the world, achieving these deliverables requires significant planning, organization, and coordination amongst numerous parties with hands-on oversight by our internal adequate resourcing for clinical and medical review at our CRO and internally. Our biostat team is preparing for the numerous statistical analysis and outputs that will be needed not only for a TLR, but also for future regulatory submissions. We and our investigators from the IMerge study are eagerly looking forward to seeing the top-line results.
Given current global events, I would like to make a few comments on the impact of the ongoing conflict in Ukraine and Russia on this trial. We only have two patients at one site in Ukraine. We know that this site is currently closed to patient visits, and we do not know whether these two patients will be lost for follow-up. In Russia, we have two patients at two sites, and these sites are currently open to patient visits. At this time, we do not expect an impact to the timing of the TLR due to this conflict. Like all of you, we're closely monitoring this evolving situation. IMpactMF, which is in refractory MF patient population. I'd like to remind everyone that this is the only phase III trial in MF using overall survival or OS as the primary endpoint.
In 2021, we opened over 50% of the planned clinical sites to patient enrollment, and we expect to open the remaining selected clinical sites by the end of 2022. For this trial, there are no Ukrainian sites participating. In Russia, we have 2 patients randomized and 3 patients in screening across 4 sites. However, we are uncertain of the impact this conflict will have on the opening of the new sites or patient treatment and enrollment at currently open sites. Under current planning assumptions around enrollment and median OS for each treatment arm, we expect that the interim analysis for IMpactMF may occur in 2024. This analysis is event-driven, the rate at which death events occur determines the timing for the interim analysis.
As a result, the number of events required to conduct the interim analysis for this study could occur before enrollment is complete, as these events will accrue throughout the enrollment period. At the interim analysis, if the pre-specified statistical OS criterion is met, then we expect this data could support the registration of imetelstat in refractory MF. If it can be confirmed in the phase III IMpactMF trial, then we believe imetelstat will be strongly differentiated from other treatments in MF currently approved or in development and will likely change the treatment paradigm for refractory MF patients. As you will hear from Anil shortly, physicians consider OS as a key significant measure of benefit for the treatment of their patients, especially for MF patients who no longer respond to JAK inhibitors due to their dismal prognosis and lack of desirable treatment options. Next slide.
Moving on from our phase III trials to the new, as part of our pipeline expansion. In 2022, we look forward to the start of three new studies. First, IMproveMF, our phase I clinical study of imetelstat in combination with ruxolitinib in front-line MF, remains on track to open for enrollment in Q2. Our interest here is to bring the potential of disease modification to MF patients earlier in their disease. The protocol is being reviewed and approved by local investigational review boards at each clinical site. Our investigator-led studies in AML and higher risk MDS, called IMpress and PILOMIR, will evaluate imetelstat as a single agent and in combination with current standard of care therapy. The principal investigators for both of these studies are highly enthusiastic.
AML continues to be an extraordinarily difficult heme malignancy to treat, and a new mechanism of action, like imetelstat, that directly affects the malignant stem and progenitor cells driving the disease could provide an effective treatment option for these patients. Due to increasing requests for participation and the expansion of the studies to more sites than initially planned, we expect the start of these studies in the second half of 2022. In addition to these new studies, we have also some pre-clinical experiments ongoing. The pre-clinical work being done at MD Anderson is evaluating imetelstat's potential to treat lymphoid heme malignancies. This work allows us to explore the potential use of imetelstat beyond myeloid malignancies, which if positive, could open several new indications in the future. We continue to expect preliminary data from these experiments at MD Anderson at the end of 2022.
Our next generation telomerase inhibitor discovery research program. Research into the characterization of the different compounds continue, and once a lead compound is identified, we will have more details. All of these activities sets up 2022 to be a busy and rewarding year, not only for imetelstat and Geron, but also for patients. Now, I will hand the call over to Anil. Anil?
Thanks, Aleks, and good afternoon, everyone. I share Chip's and Aleks excitement as we get closer to the IMerge top-line results. In my prepared remarks today, I'll first highlight imetelstat's expected product profile in lower-risk MDS and how this will differentiate the drug in the market. After that, I'll provide insights into the fast-evolving myelofibrosis market. We believe that imetelstat can play a meaningful role in the treatment of patients in both indications, in populations, and significant commercial opportunities for Geron. Next slide. In lower-risk MDS, imetelstat's product profile has been favorably received by practicing hematologists. Key attributes identified include imetelstat's ability to treat a broader set of patients, which includes both ring sideroblasts positive and ring sideroblasts negative subtypes, as well as the durability of transfusion independence. In addition, imetelstat's unique mechanism of action and potential for disease modification resonated well with hematologists in our market research.
Given that luspatercept's approval in lower-risk MDS is restricted to RS-positive patients only, we are seeing a high level of awareness among practicing hematologists for their patients' RS status. We also hear their desire for more effective treatment options for lower-risk MDS patients who are RS-negative. Thus, imetelstat's ability to broadly treat patients across both RS-positive and RS-negative subtypes was seen as important by hematologists. Also, since responses to current treatment options are limited in duration, hematologists seek durable transfusion independence for their patients. As such, the 24-week and the 1-year transfusion independence data from our IMerge phase II trial not only provides strong evidence for the durability of transfusion independence of imetelstat, but also were considered by hematologists to be highly clinically relevant for their patients. Next slide. Lower-risk MDS represents approximately 70% of the total MDS patient population.
Chronic anemia is the predominant clinical problem in patients with lower-risk MDS. Typically, erythropoiesis-stimulating agents, or ESAs, are the mainstay of treatment for the approximately 90% of lower-risk MDS patients who have symptomatic anemia and do not have del(5q), but not all patients respond to or are eligible for ESAs. Even among responders, responses typically last between 18-24 months. Treatment options remain limited for patients who have failed or are ineligible for ESAs. These patients may move on to receive hypomethylating agents, or HMAs, or luspatercept if they are ring sideroblasts positive. It's important, though, to note that HMAs are not a preferred option given their limited benefits. They are also not broadly approved across Europe for this indication.
As such, there remains a lack of effective therapies for RS-negative patients, leaving a significant unmet need for effective therapies for the remaining approximately 75% of lower-risk MDS patients and a compelling market opportunity for imetelstat in this setting. Thus, given the breadth, the depth, and the durability of transfusion independence and the potential for disease modification as evidenced by our phase II data, we expect a highly differentiated profile for imetelstat at launch in lower-risk MDS and expect imetelstat to significantly penetrate this attractive market and become part of the standard of care in this indication. Next slide. Now moving on to myelofibrosis. In myelofibrosis patients, improvement in overall survival remains a key unmet need that was highlighted by community hematologists in our market surveys. This is especially important given that patients who discontinue JAKI-based therapy have a dismal survival prognosis.
Therapies that offer disease-modifying potential naturally carry significance in the armamentarium of treatment options offered by physicians, as these therapies have the potential to alter. They also need effective second-line therapies that are non-JAKI based. Next slide. As Aleks pointed out earlier, when we asked hematologists in our surveys for the most relevant endpoint in randomized clinical trials for their JAKI-treated or JAKI-discontinued patients, the majority cited overall survival as the most relevant clinical endpoint for this population. IMpactMF, our phase III trial intended for registration, is the first and only phase III trial in refractory MF with OS as the primary endpoint. If IMpactMF can confirm the improvement in overall survival we observed in our phase II IMbark trial, we expect imetelstat will transform the care of refractory myelofibrosis patients. Next slide. On to the expected myelofibrosis market evolution.
The decade-old JAKI inhibitor therapy, ruxolitinib, has been a very successful drug in the myelofibrosis market and has established itself as the standard of care and the backbone of frontline therapy. We know that patients do not stay on this drug long term. Real-world data suggest dismal prognosis for patients who have discontinued from ruxolitinib, with median overall survival less than 12 months. As part of the natural evolution of this market, we expect to see significant expansion over the next decade as more drugs are developed to give clinicians more choices to offer tailored patient treatment options. These will include single agent or combination approaches where appropriate. We believe that the opportunity in myelofibrosis for imetelstat is driven by the expectation that all JAKI inhibitor-treated patients will become unresponsive to JAKIs over time, and therefore become eligible for imetelstat.
Like in lower-risk MDS, we expect imetelstat to have a highly differentiated profile in refractory myelofibrosis and thus to potentially become part of the standard of care in that indication. Before I hand over the call to Olivia for the financial summary, just a quick update on our preparations for imetelstat's commercialization, which are stage-gated across all aspects as pointed out by Chip earlier. In 2022, the key areas of focus for the commercial organization are on activities that have long lead times, such as commercial supply chain planning and third-party logistics setup, refining our value proposition across all stakeholders, and building a deep understanding of the customer base. While we have initiated these pre-commercial activities, the bulk of our commercial investments will happen after top line results from IMerge phase III. With that, I will now hand the call over to Olivia. Olivia?
Thanks, Anil. Next slide. As expected, overall operating expenses for the fourth quarter and full year 2021 were higher than the same period in 2020. Total operating expenses for the three and twelve months ended December 31, 2021 were $32 million and $115.4 million respectively, compared to $23.3 million and $77.2 million for the same period in 2020. The increase in research and development expenses primarily reflects increased clinical development costs with our two ongoing phase III clinical trials, higher imetelstat manufacturing costs for producing validation batches at contract manufacturers, and higher personnel-related costs for additional headcount. The increase in general and administrative expenses primarily reflects new costs in connection with pre-commercial activities, including modernizing our internal infrastructure to support a potential commercial launch and higher legal costs.
We ended the 2021 fiscal year with $212.7 million in cash and marketable securities, which we believe is sufficient to fund current operations through the end of the first quarter of 2023. For guidance on 2022, we expect non-GAAP total operating expenses to be in the range of approximately $140 million-$150 million. This guidance reflects expenses for supporting the two ongoing phase III clinical trials as well as the new exploratory studies in frontline MF and AML, finalizing validation batches of imetelstat at contract manufacturers to enable future production of imetelstat for clinical and commercial purposes, initial manufacturing for commercial inventory production, preparations for top-line results in lower-risk MDS and future regulatory submissions, initial commercial readiness activities, projected increases in headcount, and larger interest payments due to higher outstanding debt.
With that, I will now hand the call over to Chip to share our key upcoming corporate milestones. Chip?
Next slide, please. Thanks, Olivia. As I commented at the beginning of this call, 2021 was a year of critical execution and accomplishments for Geron as we drive towards significant future readouts from our phase III trials and ultimately commercialization of imetelstat. 2022 is equally important. Next slide, please. Our expected key upcoming milestones include ensuring delivery of top-line results for the phase III IMerge lower-risk MDS trial in time for disclosure in early January 2023. Assuming positive TLR, we are also preparing for a potential submission of the NDA in the first half of 2023 and an MAA submission in the second half of 2023, and subsequent regulatory approval and commercialization in lower-risk MDS as early as the first half of 2024 in the U.S.
As well, our team will continue executing on IMpactMF with opening the remaining selected sites by the end of the year. If we accomplish this, we expect that the planned interim analysis of IMpactMF may occur in 2024. Taken both separately and together, the upcoming readouts from these two phase III registration trials have the potential to transform Geron from a late-stage development company into a commercial stage company, and thus to realize our vision of Geron becoming a leader in the treatment of hematologic malignancies. Finally, we expect the new programs in our expanded pipeline to progress meaningfully this year and to begin the process of potential value accretion beyond our initial indications for imetelstat and possibly even beyond imetelstat itself.
Looking forward, if we accomplish each of these important value accreting milestones successfully, we expect imetelstat will change the treatment of lower-risk MDS and refractory MF with significant improvement for patients. Thanks very much for your interest in the company, and we'll be glad to take your questions. Operator, please open the call to questions.
At this time, I would like to remind everyone, in order to ask a question, please press star followed by the number 1 on your telephone keypad. Your first question comes from Gil Blum with Needham & Company. Your line is open.
Hi, good afternoon, everyone. Maybe I had a quick question on myelofibrosis. There's a bit of a shifting of the treatment landscape with the very recent approval of pacritinib. Do you think that it's gonna extend the amount of time patients spend being refractory, i.e. living a little longer? Does that potentially increase the market for relapsed refractory MF? Thank you.
Hi, Gil. Thanks very much. This is Chip. Can you hear me okay?
Yes.
Okay, great. Okay. I think I'm gonna let Anil Kapur just take a first crack at that, and others may have a few other comments. The question was, will the pacritinib approval shift the landscape in any way, and in particular increase the number of patients who are JAKI refractory? I think that was the question. Go ahead, Anil.
Yep. Sure. Thanks for the question, Gil. Pacritinib, as you know, was just approved for severely thrombocytopenic patients. These patients represent a small fraction of myelofibrosis patients, and it's different from the population that imetelstat can serve. We welcome the addition of all of these new JAKI therapies for MF patients. I think to answer your question, Gil, it all depends upon the patient population actually on pacritinib. If the patient population on pacritinib is less than 50,000, which is their indicated label, that population will remain distinct from the populations served by imetelstat. However, we think that this unmet need is very high, and we welcome the opportunity.
The general gist, and I think I can say that for all therapies in development, is that over time you will see this market significantly expand and, as we said, provide physicians with multiple choices across all lines, leading to a much, much larger second-line, third-line plus treatments in myelofibrosis, very similar to the dynamic as an example that we saw even in myeloma.
Thanks, Anil. Gil, any follow-up question on that?
Maybe I'd sharpen that last point a little further. It is my understanding that the, you know, the thrombocytopenia is part of the disease progression as well as an outcome of the treatment of JAKIs over time. Basically, if patients live long enough, they will become thrombocytopenic, so it's kind of like a funnel where your patient's gonna constantly progress to being more and more thrombocytopenic. Am I misunderstanding that?
I'll let Aleksandra take that since she's the clinician on the call. Go ahead, Aleks.
Yeah. Can you hear me?
Yes.
Can I take it? Yeah, sure. Yeah, Gil, you're correct in that saying that patients that progress over time, right, become thrombocytopenic. In addition to that, as we know, the available or the approved JAK therapy at the moment also doesn't serve these patients or over time these patients, you know, with time, the patients that are treated with ruxolitinib, for example, become thrombocytopenic. I think your conclusion is right there and then these patients, as they progress, if they do have the appropriate number of platelet counts to be treated with imetelstat, they could, you know, they certainly are a option for treatment or could potentially be an option for treatment with imetelstat.
Yeah. Maybe I'd conclude some comments about this, Gil. I think the point that as we see it is, most of the patients who probably will end up on pacritinib, at least early in the course, would come from the front line or near front line, possibly second line with low platelet counts. I think your question presupposes what will happen as patients become much more ill and, ultimately, patients become thrombocytopenic, neutropenic all on their own with their bone marrow fails. While it's certainly possible that some of those patients would benefit by the availability of a drug that is not limited by platelet counts, on the other hand, most of those patients are really failing JAKI therapy in other ways, symptomatic and otherwise.
I think that the dynamic will continue to evolve and, honestly, as Anil said, we do welcome these other entrants, especially into these areas that are particularly difficult patients to treat. How exactly it's gonna play out in numbers, I'd put my money on the entire market expanding as more and more patients become eligible for frontline therapy. That's just my point of view. Okay, maybe we could move on to the next question.
Yeah. One additional question and then-
Sure.
That would be for me. Do you guys have any timeline on potential readouts from the frontline combo study? This is a very interesting study.
Yeah. Gil, I think it's a little early to be commenting on that. All we know is that we're feeling comfortable that we'll begin the study or we'll open the site for enrollment in the first half of this year. We don't know exactly how long it will take to ladder up the different dosing, right? You have to take these studies quite slowly in the interest of safety, and that's been true for every combo study I've ever done, really pretty much any indication. The question will be how long do we have to stick and what do we see in the way of adverse events as we add on? I don't think there's a good expectation at the moment.
I don't know if Aleksandra has any further commentary about that. Aleks?
Yeah. I just wanted to make it clear that we expect to start the study in the second half of 2022. That was something in my part of the script, just because there is a bit more. Oh, I'm sorry. I got ahead.
Yeah.
Yeah. Chip was correct. I'm sorry. I moved to the investigator-led studies. Chip is correct that the company-sponsored study on timeline to start enrollment in the first half. As Chip said, we are first trying to safely combine the two drugs, and we are going to look for the safe dose. But with that said, right, it's an open label study, so we will be able to evaluate the potential efficacy of the two drugs as we go on, ideally. That's one addition that I wanted to give to Chip, too.
Yeah.
Okay, excellent. I think that's it for me for now, and we'll continue to watch your progress.
Thanks very much, Gil. Next, question.
Your next question comes from the line of Stephen Willey with Stifel. Your line is open.
Hi, this is Ellen on for Steve. Thank you for taking the question. Maybe first one on the work that's being done on the second-generation telomerase inhibitor. I'm just wondering what the ideal profile that second gen candidate would look like in your opinion and, you know, what key improvements would be made compared to imetelstat. Thanks.
Yeah, sure. I'll take that one. Our number one choice and what we're really going for is an orally available small molecule that has all the usual benefits and one that would have all of the usual benefits of small molecule development, both in terms of manufacturing and also in terms of timing. Of course, the oral availability would be welcome in certain indications, in certain types of utility. It's a tall order. We started out with a couple of different scaffolds, but we're still looking for a lead compound in that regard. I have a lot of hope here, but honestly, we're not quite ready to report any specificity around this.
We will attempt to give a little bit more specificity once we have a lead compound. I think we've said in the past that that will likely take us the remainder of this year.
Okay, great. Thanks. With regards to the frontline MF study, I know, you know, primary point is really safety and the combinability of these two drugs. Just wondering from an efficacy perspective, you know, total symptom score, kinda what the bar is for success here for moving the program forward.
Sandra, you wanna comment on that? Did you hear the question?
Yeah, sure. Yeah, no, I did hear it. I just wanted to, you know, maybe start off by saying that really the enthusiasm on our side for this combination is really to bring the disease-modifying potential or disease-modifying data that we have seen with imetelstat in the relapsed/refractory setting. While, yes, we, you know, we have to really look into the endpoints that are easy to evaluate, like a TSS or an SVR35, we will certainly be looking into other efficacy endpoints as well, potential CRs, PRs, improvement of fibrosis as well. It's really going to be the totality of the data that we will be evaluating in this IMproveMF phase I study. I think that's kind of how we are looking at this study.
Okay, great. Thank you for taking the questions, and congrats on the progress.
Thank you.
Thank you.
As a reminder, if you would like to ask a question at this time, please press star followed by the number one on your telephone keypad. Your next question comes from the line of Joel Beatty with Baird. Your line is open.
Hi. Thanks for taking the questions. The first one is on the IMerge phase III trial in MDS. Could you discuss what gives you confidence that the trial is sufficiently powered? I believe, you know, one example of something that could be successful is a 30% rate in the imetelstat arm versus 7.5% in the placebo arm. You know, I realize it's just an example, but, you know, could you talk to how realistic those numbers are?
Go ahead, Aleks. Let's right up here, Aleks.
Yeah. Joel, I'm not sure if I heard you well in the beginning, but I think you asked whether we have discussed this with the health authorities. If that was the question?
No.
No? That was not at all?
No.
Okay. I'm sorry. I really have a hard time hearing.
You're having a little bit of trouble hearing.
Yeah. I think that the
Let me repeat.
Yeah.
Let me repeat the question, and maybe I'll take a crack, and then Alexandra, you can fill in. Joel, I understood the question to be what gives us confidence in the outcome of the IMerge phase III lower-risk MDS study. You cited the fact that we've commented in the past that we have a fairly conservative powering assumptions, meaning that although we saw a 42% rate of eight-week TI in our phase II, we put into our powering assumptions a 30% rate, the very conservative rate. We also have noted that although in other trials, the placebo rate in, for example, MDS-005, which was a competitor study in a similar patient population that had a placebo rate of around, I think it was, 3%-5% maximum.
I think it was 4.5%. We've actually assumed for our statistical power assumptions, again, a very conservative 75%. That we've talked about before. The other elements that make us feel really comfortable going into TLR are the similarity of the patient population. These are all patients who come from very, very similar populations. They're non-del(5q). They all are relapsing and refractory to ESAs. They have not all are naive to HMAs and to lenalidomide. This, by the way, was a very similar patient population to the MEDALIST study for luspatercept, which was used for their approval.
Finally, I think that we feel very comfortable that the drug is being used in exactly the same way. Starting dose is 7.5 milligrams per kilogram. We've refined, of course, for phase III. During the course of phase II, we refined some of the dose modifications to be made during the study. Overall, I think we would say we have a very similar patient population, very similar treatment regimen, and conservative statistics.
Great. Yeah, that's really helpful. Thanks for those points. Maybe moving on to a question on the IMpactMF trial. Are you able to discuss how the blinded event rate is comparing to the expectations going into the trial?
No, I don't think we're going to plan to do that. You're absolutely correct that the study is blinded. At this point in time, we don't have any plans to discuss that event rate. It's a long trial, and we'll see how things progress, but right now we're focused on enrollment.
Great. Got it. Yeah, makes sense. Thank you.
Okay, great. Thanks.
This concludes our Q&A session. I'd like to turn the call back to Dr. Scarlett for closing remarks.
Okay. Well, thanks very much for those excellent questions. Thanks everybody for joining us today. We really appreciate you taking the time to dial in and participate. We look forward to sharing the achievements of a lot of these milestones in the coming year. Stay healthy, everyone, and keep safe. Thank you. Bye-bye.
This concludes today's conference call. You may now disconnect.