Good morning. I'm Rushmie Nofsinger, Vice President of Corporate Affairs and Investor Relations at Scholar Rock. Welcome, and thank you for joining us today for our Q3 2023 Business Update Call. This call is audio-only. You can access the slides that we'll be referring to on the Events and Presentations section of the Investor Relations page on the Scholar Rock website. Moving to Slide 2. Before we begin, I want to note that we'll be making various statements about Scholar Rock's expectations, plans and prospects that constitute forward-looking statements for the purposes of the safe harbor provisions under the Private Securities Litigation Reform Act of 1995. Any forward-looking statements represent our views only as of today and should not be relied upon as representing our views as of any future date. Please refer to our SEC filings for the full disclosure of all the risks. Turning to Slide 3. I'd like to introduce the members of the Scholar Rock team, who will be presenting during today's call and will be available for questions after the conclusion of the formal remarks. I am joined by Jay Backstrom, CEO of Scholar Rock; Ted Myles, Chief Operating Officer and Chief Financial Officer; and Mo Qatanani, Head of Research. I will now turn it over to Jay.

Thank you, Rushmie, and good morning, and welcome to our Q3 business update call. We've made excellent progress so far this year and in particular, in the third quarter, and I'm very excited about our future and believe we are well positioned for success. Moving to Slide 4. Before I review the details of our progress, I want to start with Scholar Rock's pioneering approach to targeting the TGFß superfamily of growth factors. The picture on the left of the slide depicts the latent complex that contains an active growth factor. The scientific insight that led to the understanding of the structure of this latent complex is part of the foundation of our industry-leading platform that targets the TGFß superfamily of growth factors by selectively and specifically blocking their activation by locking up the growth factor in the precursor or latent form. This highly specific approach limits the off-target effects that have been observed with less selective approaches that target the active forms of the growth factors or interfere with their receptors such as the activin receptors. Apitegromab, our lead clinical program targeting latent myostatin, prevents the formation of the active form of myostatin, a negative regulator of muscle growth, and leads to an increase in muscle mass and function in non-clinical models and is the first anti-myostatin therapy to demonstrate clinical proof-of-concept. Moving to Slide 5. I was very excited to announce that we are leveraging our R&D platform and deep knowledge of myostatin biology to expand into a new therapeutic area of cardiometabolic disorders with our novel, highly potent and selective anti-myostatin antibody SRK-439 in combination with the GLP-1 receptor agonist. Scholar Rock has a long-standing interest in targeting myostatin for cardiometabolic disorders, given the role that muscle plays in glucose metabolism and insulin sensitivity. As you'll hear from later in this morning's presentation, our approach to blocking myostatin is ideally suited for use in both SMA and cardiometabolic disorders since by blocking myostatin and only myosin, we avoid off-target toxicities. Safety is critically important in treating SMA and in weight loss therapy, and we believe our selective approach, as we've seen with apitegromab in our SMA program to-date, should lead to a favorable overall benefit-risk profile. Moving to Slide 6. Targeting the TGFß superfamily has broad therapeutic applications given the central role this family of growth factors plays in a wide range of cellular processes, including growth and differentiation. Our research teams have produced a robust pipeline of product candidates targeting latent myostatin and latent TGFβ1. I'm very pleased with the significant progress that we've made on our pipeline since the beginning of the year. Moving to Slide 7. For this morning's call, I will start with an update on our clinical programs, highlighting the status of SRK-181, our selective anti-latent TGFβ-1 antibody in Immuno-Oncology followed by an update on the progress we've made with our number one priority, apitegromab and SMA, and then turn to Mo to discuss our entry into cardiometabolic disorders with our novel anti-myostatin SRK-439. Moving to Slide 8. Slide 8 provides an overview of the DRAGON drop. As a reminder, the main objectives of the DRAGON study, in addition to dose ranging and safety, included establishing proof-of-mechanism and proof-of-concept that by blocking TGFβ1, a key driver for resistance to checkpoint inhibitors with SRK-181 in combination with pembrolizumab, we could overcome the immunosuppressive environment and restore responsiveness to the checkpoint inhibitor. To achieve these objectives, the Part B portion of the study included expansion cohorts in several tumor types and required all patients to have progressed on the most immediate prior anti-PD-1 or PD-L1 treatment. The study is rich in biomarkers, including paired biopsies to assess if SRK-181 could overcome an immune exclusion phenotype and drive CD8+ T Cells into the tumor, as was demonstrated in our non-clinical models. The team made excellent progress with the DRAGON study since the start of the year, culminating in two poster presentations at the Annual Meeting of the Society for Immunotherapy of Cancer, this past weekend. The first poster focused on biomarker data in support of proof-of-mechanism. And the second provided a clinical and biomarker update from the renal cell carcinoma cohort from the Part B expansion, the cohort with the most patient data, including follow-up. I will start with a review of the biomarker poster. Moving to Slide 9. This poster focused on biomarker data and support of proof-of-mechanism. Based on paired biopsy data demonstrated that SRK-181 in combination with an anti-PD-1 therapy increased the infiltration of CD8+ T Cells across several tumor types, including melanoma, shown here. This was seen in the compartmental analysis that measures the percentage of CD8+ Cells in the tumor – Tumor Margin in Stroma from 2 melanoma patients. As shown on the graph on the left, there was an increase in CD8+ T Cells observed after treatment overcoming an exclusion or desert phenotype, which was present at baseline. Similarly, as shown in the histopath image on the right, there's an increase in intensity of brown staining, representing CD8+ T Cells in the post-treatment biopsy, also demonstrating the influx of CD8+ T cells into the tumor. We were excited to see these data, which essentially reproduced the non-clinical findings that form the scientific rationale for SRK-181. Turning to Slide 10. The second poster presented at SITC provided an update on the renal cell carcinoma cohort from Part B. Overall, 28 patients were evaluable for response. It's important to note that the patients enrolled represented a heavily pre-treated population, who received a minimum of three prior lines of treatment, including a checkpoint inhibitor and tyrosine kinase inhibitor. All had disease progression on their prior anti-PD-1, PD-L1 treatment. This slide includes three graphical displays from the poster and highlights treatment duration, as shown in the swimmers plot, antitumor activity, as shown in the waterfall plot and the spider plot that illustrates both duration and tumor response. As can be seen, there is clear evidence of tumor reduction with a 21% overall response rate, that is durable beyond six months and a disease control rate of 57%. The overall response rate is significantly above what we would expect from a checkpoint inhibitor alone, in the setting of prior anti-PD-1/PD-L1 progression, which is expected to be less than 5%. With respect to safety, the combination was generally well tolerated with the most common treatment emergent adverse events, predominantly skin toxicities, of rash and pruritus. Moving to Slide 11. In summary, the DRAGON trial delivered on its objectives of showing Proof of Mechanism and Proof of Concept with promising overall response rates in heavily pretreated relapsed/refractory patients with clear cell renal carcinoma, all of whom progressed on prior treatment with a PD-1 or PD-L1 therapy. Now the DRAGON trial has met its objectives, we plan to enclose enrollment in December, begin closeout activities while we continue to treat those patients who continue to benefit from therapy and remain on study. We also plan to present ongoing data from the DRAGON trial at future medical meetings. We would like to take this opportunity to thank the investigators, the study staff and, in particular, the patients and their families who participated in or are currently participating in the DRAGON trial. Regarding the SRK-181 program overall, we believe the data from the DRAGON trial support advancing the program, and we plan to conduct an end of Phase 1 meeting with FDA in the first half of 2024 to determine the next steps. Turning to Slide 12, I'll now focus on our lead clinical program with apitegromab in Spinal Muscular Atrophy or SMA. As a reminder, SMA is an inherited neuromuscular disorder caused by a deficiency in a protein, the SMN protein that is essential for the survival of motor neurons, which in turn is responsible for controlling muscle movement. When the SMN protein is deficient, the motor neuron degenerates, resulting in muscle weakness and atrophy, leading to significant impairments, including the inability to sit, stand, and walk depending on the extent of involvement. Currently, there are three approved therapies for SMA, all of which work to increase the amount of SMN protein, but none target the muscle directly. Apitegromab, by targeting latent myosin prevents the formation of the active form of myosin, a negative regulator of muscle growth, and is the first anti-myostatin therapy resulting in improvements in motor function, as shown in our Phase 2, Proof-of-Concept Study, TOPAZ. Moving to Slide 13. As we shared at the 2 SMA event in June, we were excited to present 36-month data from the pooled non-ambulatory patients from TOPAZ, the same patient population included in our Phase 3 registration study, SAPPHIRE. As shown, there was robust, consistent and sustained improvement in the motor function scales, the extended Hammersmith and the Revised Upper Limb Module, which are also the primary and secondary endpoints in SAPPHIRE, as well as improvements in the patient-reported outcome measures, as reflected in an increase in activities of daily living and reduction in fatigue, all measures that are consistent with improvement in muscle strength. Turning to Slide 14, I'm very pleased with the progress we've made this year toward executing on the promise of apitegromab in SMA. We have met or are on track to meet all of the 2023 goals for the program that we outlined at the beginning of the year. In addition to reporting the 36-month TOPAZ data in June and the 2 SMA event, we also opened the Onex long-term extension study, which will serve as a platform for patients from both TOPAZ and SAPPHIRE to continue to receive apitegromab. Importantly, Onex provides an opportunity to further strengthen the body of evidence on long-term safety and efficacy. As we announced in September, we completed enrollment of our Phase 3 registration study, SAPPHIRE, a major milestone for the study and look forward to reporting our top-line results in Q4 2024. Assuming success and regulatory approval, we expect to be a commercial company in 2025. From a commercial perspective, the launch of apitegromab will be leveraged by the established SMA market. Finally, our team is in the planning stages for additional follow-on SMA studies, including in children under the age of two, and in ambulatory patients, allowing us to extend the potential benefit of apitegromab to the broadest patient population possible. Now moving to Slide 15. And I'd like to turn this portion of the program over to Mo, who will provide an overview of the cardiometabolic program. Mo is the Head of Research and brings a wealth of experience in both neuromuscular and cardiometabolic diseases. As I mentioned in my opening remarks, Mo's team has been working on targeting anti-myostatin for cardiometabolic diseases for quite some time, and Mo will walk you through this research. Mo?

Thank you, Jay, and good morning, everyone. Now on slide 16. Our approach of targeting the pro and latent forms of myostatin allows us to have exclusive selectivity to inhibit myostatin signaling and nothing else. A nonselective approach that targets pathways outside of myostatin or muscle has the potential to have deleterious effects. For example, inhibition of the closely related GDF11 growth factor signaling may have negative impacts on bone, and inhibition of activins has demonstrated effects on reproductive biology, likely limiting the use of products that target this pathway in women of child-bearing age. By inhibiting myostatin and only myostatin, our antibodies provide a profile that drives efficacy without the potential liabilities that come with nonselective approaches, which is critical, especially in this patient population. We are now on slide 17. Obesity is recognized as a top global public health challenge with an estimated 1 billion adults worldwide, including half of the population projected to be obese by 2030. This is associated with several serious comorbidities like heart disease and type 2 diabetes, presenting staggering costs to the health care system. Weight loss by any means leads to loss of not only fat but also lean mass, and this is evident in the GLP-1 receptor agonist mediated weight loss that is experiencing rapid uptake, where lean mass losses may be 25% to 40% of the total body weight loss. Loss of lean mass is a key predictor of adverse outcomes in older patients, and maintaining lean mass through exercise during weight loss has demonstrated longer-term benefits versus weight loss alone. Therefore, it is possible that maintaining lean mass in the context of weight loss may promote additional fat loss as well as greater long-term metabolic benefits. Moving to slide 18, where we'll be discussing SRK-439. SRK-439 is a novel preclinical anti-myostatin antibody that is in development. As mentioned earlier, we leveraged our extensive expertise in myostatin structure and biology to develop this molecule to specifically address the patient population of cardiometabolic disorders. SRK-439 has attractive properties and potential to address the muscle loss associated with weight loss. It has high affinity for pro and latent myostatin, potentially leading to efficacy at lower doses. It maintains myostatin specificity with no GDF11 or activin binding to limit any potential undesirable off-target effects, especially in this patient population. It also maintains a good developability profile and is amenable to subcutaneous formulation and dosing. Now on Slide 19, where we show our efficacy data with SRK-439 in combination with GLP-1 receptor agonist in diet-induced obesity models, a standard model used in the field. As expected, the decrease in body weight induced by the GLP-1 receptor agonist, liraglutide, in this case, led to a decrease in not only fat mass but also lean mass, as you see with the TAM bar. Combining SRK-439 with a GLP-1 receptor agonist confirmed our therapeutic hypothesis and led to a dose-dependent reversal of lean mass loss in addition to enhancement of fat mass loss. Slide 20 highlights the efficacy of SRK-439 in the diet-induced obesity mouse model in combination with semaglutide, a more effective GLP-1 receptor agonist. Semaglutide led to significant loss of lean mass in addition to fat mass loss as seen in the TAM bar. However, when combined with SRK-439, the loss of lean mass induced by semaglutide alone was dose-dependently reversed, leading to maintenance of lean mass while enhancing fat mass loss. It is worth noting that we see lean mass preservation with doses as low as 0.3 mg/kg of SRK-439, which highlights the favorable profile of SRK-439 for development in this indication. Turning to Slide 21. To summarize, our approach is explicitly selective in targeting myostatin and myostatin only and avoids potential liabilities of our target inhibition. The selective inhibition of myostatin in combination with GLP-1 receptor agonist driven weight loss may lead to healthier, more durable weight management, and we look forward to testing this in the clinic. Now on Slide 22. In summary, our preclinical data supports advancing SRK-439, a novel investigational myostatin inhibitor for the treatment of cardiometabolic disorders with initial focus on obesity. We are moving SRK-439 towards IND submission in 2025. To inform the development of SRK-439, we plan to initiate a Phase 2 proof-of-concept trial of a particular map in combination with GLP-1 receptor agonist in obesity in 2024. The data readout of that trial is expected in mid-2025.

Thanks, Mo. Moving to Slide 24. 2023 has been a year of significant execution across our portfolio, and we're well positioned going into 2024. We're seeing great productivity coming out of our scientific platform as our unique approach of targeting the latent form of growth factors to achieve exquisite selectivity appears to be improving patient outcomes in SMA and in oncology. We are excited to be applying this selectivity to our cardiometabolic disease areas where we believe safety is so important, and our approach is highly differentiated. Our upsized public offering that we completed last month puts us in a strong financial position with our cash runway that extends into the second half of 2025. We're focused on advancing the myostatin programs, SMA and cardiometabolic. Additionally, we believe we're well positioned to bring in non-dilutive funding as we continue to evaluate potential partnership opportunities for other programs within our portfolio. We view strategic business development as an important way to advance promising programs by leveraging the infrastructure, capital, and expertise of other companies. We ended the third quarter with $219 million of cash and cash equivalents, and our October capital raise netted approximately $93 million. Our capital allocation strategy includes a substantial reduction in our spend on SRK-181 as we complete enrollment of DRAGON and continue to support remaining patients on study. Our primary focus as we conclude 2023 and look to 2024 includes investments to advance apitegromab in SMA and our newly announced cardiometabolic program. With the capital enhance, promising programs underway and our strategic imperatives aligned with our core competency, unparalleled selectivity of myostatin inhibition, we are excited about the future and our ability to serve patients with our important novel therapies. This concludes our formal remarks. I'll now turn it over to the operator, so we can start the Q&A.

Thank you. The floor is now open for your questions. Your first question comes from Michael Yee with Jefferies. Your line is now open.

Hey, guys, thanks for the question, and congrats on all the progress. We had two questions. One on SMA and one on cardiometabolic. SMA, in your Phase 3, I believe the primary analysis is based on ages two to 12, and I was wondering if you have any thoughts around the proportion of the study that is probably more two to five versus, say, older, and whether there is any pre-specified analysis that has an analysis to look at the younger patients versus the older patients in that study after observing what happened with DMD gene therapy and how that played out if there's a pre-specified analysis for younger patients? And then on cardiometabolic, an interesting hypothetical question, I appreciate that this is an obesity drug that you're trying to develop, do you anticipate that the regulatory path is traditional obesity just weight loss, whether there's an endpoint also that would be accepted by the FDA for muscle gain, and I was wondering how you think about that? Thank you.

Yes, great. So Michael, thank you. This is Jay. Thanks for the question. Let me start with the SMA. So yes, our primary analysis is the two to 12. We haven't disclosed the proportion of that group who are between the ages of two and five. And at this juncture, our primary analysis and pre-specified analysis certainly include the older cohort, but as you know, upon top line data, we have the opportunity to look across the age groups. So we will certainly look at that in the top line results. I think that took care of the question on the SMA patient population. With respect to cardiometabolic, yeah, very interesting question. I think with respect to the current approval for weight loss, it is the amount of weight loss that occurs that is the primary endpoint, as you know, this is an evolving field. I think recognizing that the need to preserve lean muscle mass is really critical, and the efforts now that we're in and others are in, I think will help inform future regulatory endpoints, but we will need to demonstrate at some point across the program improvements in either function or patient-reported outcomes. So I think that will need to be a standard part. But I think it's a stay tuned as I think as we move forward. For our proof-of-concept study, we're certainly going to be focused on demonstrating that we can preserve and maintain the muscle mass. I think for a proof-of-concept, that's mechanistically sound, and that's our approach going forward.

Thank you, guys.

Our next question comes from the line of Allison Bratzel from Piper Sandler. Please go ahead.

Hi, good morning team. Thanks for the update today, and thanks for taking my question. So first, on SRK-439, maybe a question for Mo. Could you just provide some more color on the different properties of 439 compared to apitegromab, and just really distill for SRK-439 is better suited to go forward in obesity. It seems the subcutaneous format is a major differentiator there. Just curious if subcutaneous administration of apitegromab is something you've explored. Any color there would be helpful. And then, just on a related note, could you help us understand what is gating to IND filing for apitegromab in obesity? And also, same question, what's gating to IND filing for 439 and what gives you confidence that IND filing will be ready to go in mid-2025? Thanks.

Hey Ally, this is Jay. Maybe I'll take one part of that three-part question, and then I'll turn it over to Mo. And there's the question around the IND, what's required to get the IND filed for apitegromab. Why I'm really delighted that we have the opportunity to proof-of-concept with apitegromab is because it's already a clinical-stage asset. So it's a matter of really putting together the scientific rationale and submitting the IND for a new division to agree, and we get to cross-reference a lot of the existing documents in the current apitegromab’s IND and SMA. So it's really a matter of completing the regulatory dossier to do that and then engage the FDA. So that work, frankly, we had started even prior to announcing our going into this area. Then maybe I'll let Mo talk about the IND-enabling work required for SRK-439 and then more details.

Yes. Thanks, Jay. I mean I'll start with talking about SRK-439. SRK-439 is a novel molecule that we developed based on our extensive understanding of myostatin and the structure and the obesity space. It is highly selective, as we mentioned, it only binds myostatin utilizing our platform. It has attractive property, and from the get-go, we developed it to target this patient population. So it has very high in vitro affinity leading to potentially lower doses when you're looking at efficacy with these. We've seen that in the mouse models that we've done, and we continue to do in other models as we develop the molecule. It also amenable to high concentrations. Again, this is to support subcutaneous profile, especially for this patient population. So overall, the profile of SRK-439 was designed by design for this patient population to have higher affinity and efficacy with lower doses and concentration to enable subcutaneous dosing. From an IND-enabling studies, we're going forward with the typical IND-enabling studies. We're initiating all of the IND-enabling studies as we move forward into next year, as you see the Tox, the PK studies and all of these things as well as cell line developments, etc.

Got it. Thank you.

Our next question comes from the line of Tessa Romero with JPMorgan. Please go ahead.

Good morning. Thanks for taking my question. Two questions from us this morning, if we could. First one is, how do you disclose the statistical test you are using and what the powering assumptions are for the SAPPHIRE trial around the primary endpoint of the main Hammersmith change from baseline at 12 months? If not, what can you tell us at this time as to how we should be thinking about this? And secondly, a related question. Will you consider disclosing the baseline characteristics before the top line result next year? Thanks, guys.

Yes. So this is Jay. I'll take the questions. From the statistical powering assumptions, we've really not fully disclosed it, but just to kind of put color to that for the Hammersmith. We expected certainly to be able to demonstrate a three-point change. By the way, we power the trial and have adequate power to demonstrate that. Again, we're doing hierarchical testing on that and then the following secondary endpoints. I think we're well positioned to replicate in SAPPHIRE what we saw in the TOPAZ study. And then with regard to baseline characteristics, Alli, we're looking at that very critically as sort of our publication planning and data disclosure plans, really, we try to do that time to important Congresses, as we think in conferences as we think about over the year. So more to come as we disclose that, but not likely to occur anytime in the near-term, given the cadence of the medical conferences.

Okay, great. Thanks for taking our question.

Our next question comes from the line of Srikripa Devarakonda from Truist Securities. Your line is now open.

Hey, guys. Thank you so much for taking my question. As you develop apitegromab and SRK-439 and obesity, I actually had a couple of maybe basic questions on myostatin and obesity. Some studies have shown that myostatin is upregulated in obesity. Just wondering, how well this dynamic has been characterized in patients, is there a lot of variability, and how do you think that could potentially impact how effective the drug could be in these patients, especially if you consider the background of obesity versus SMA where you've shown activity? Given that the studies show myostatin is also reduced as patients lose weight, do you think there's an optimal window where you treat patients with anti-myostatins? Thank you.

Yes. So maybe I'll start just talking about what we would expect to see in clinic with apitegromab and then following with SRK-439 and obesity. I think what we can say, which is very clear now and we've shown that, I believe, in the TOPAZ study is that targeting myostatin does result in preservation, if not an increase in lean muscle mass. I think we've shown that functionally in TOPAZ. I think there's consistent observation across. So myostatin is a very good target. It certainly should be able to do that in the setting of obesity, where you have normal muscle. So I think that's the case. The fact that there was up-regulation of signaling in myostatin is interesting, but I do believe that we'll have an opportunity to demonstrate that in this setting just as we will demonstrate it in the SMA setting.

Great. Thank you.

Our next question comes from the line of Etzer Darout from BMO Capital Markets. Your line is now open.

Great. Thanks for taking questions and congrats on the progress. How are you thinking about the development of SRK-439, I mean, given the size of the obesity indication? And I guess is the proof-of-concept data with apitegromab the catalyst for an update, if you will, on development plans? And then maybe on SRK-181, just maybe next steps for the program, a little bit more color on what you described earlier during opening remarks and maybe the opportunity for future programs to be in sort of earlier lines of RCC, for example. Thank you.

Yes. So let me start with 439 and proof-of-concept and sort of overall path forward. Again, I think we've shown to date at Scholar Rock that we can run randomized Phase 3 studies; we can run proof-of-concept trials. As I think about the cardiometabolic space, certainly to get Apitegromab proof-of-concept, which will really, in my opinion, validate our approach. As we report that out, we'll then at the time, open up with 439 getting right into clinic, really positions us to drive 439 rapidly forward also to that proof-of-concept. That's our near-term horizon. Anything beyond that, I think we're still open for discussions around how we get the bigger, broader trials. But I think for what we can do in our hands, I think we can certainly drive value for the company by driving the clinical data in that proof-of-concept setting. That's really our thinking around. What Mo laid out very beautifully about how we're looking at both Apitegromab and 439. For 181, you know, the data that I shared on the way I tried to put the color on it, this is really a tough group to treat. To see this level of response rate in this heavily pre-treated, failed on checkpoint inhibitor, I think really shows that proof-of-concept, which is why we reach those conclusions. I think like in any therapy, particularly in immunotherapy, earlier lines of therapy are really the place to take any treatment if you really want to have a major impact because patients have been so beat up and progressed so much through these therapies that getting earlier makes sense. Frankly, that's the whole concept behind the end of Phase 1 meeting. It's really to engage the FDA, review our data, and then begin to work with them to kind of lay out what would be the next logical steps in any further development of 181. As Ted said, right now for us today, we are really pleased with the way DRAGON performed. I think it's met its objective; it's done its job. We'll wind that down, reset, and take a look at what's happening with the FDA interaction. But in the meantime, in 2024, it's really all on our focus is on our anti-myostatin programs.

Great. Thank you.

Our next question comes from the line of Andres Maldonado with H.C. Wainwright. Your line is now open.

Hi. Thank you for taking my question. I reiterate my congratulations on all the progress. So one quick question from us on 439. So I guess in the context that the goal of next-generation obesity program aims to really hone in and follow the issue of variability of patient response. Could you maybe talk about how much in this variance you ascribe muscle loss, driving that variation in patient response? And then a follow-up question to that would be, given the safety and tolerability of apitegromab, which has been positive, are some of the treatment-emergent events more worrisome in the context of the combination? Thank you very much.

We may collaborate with Mo on your question, which concerns the variability in weight loss associated with the current GLP-1 receptor agonists. There is a noticeable range in outcomes; some patients experience significant weight loss, while others reach a plateau. Reviewing the literature and data, it seems that these differences might be influenced by patients reaching adequate doses. Several factors impact overall weight loss, including muscle mass loss, which we see varies between 20% and 40%. These events are interconnected, but our main focus is on preserving muscle mass, which we anticipate will maintain a consistent effect. Therefore, we will advance our proof-of-concept studies with this in mind. Regarding safety, which you've indicated is a point of interest, we've highlighted its importance. Historically, weight loss therapies have been effective but have faced issues related to toxicities and safety that hinder their long-term use. However, the current GLP-1 receptor agonist therapies, despite extensive patient exposure, have shown effects without the severe issues seen previously that would necessitate halting these treatments, which is a positive development. Any new therapies introduced to mitigate negative effects such as muscle loss should ideally pose no additional risk of toxicities. Our strategy, targeting myostatin and non-myostatin pathways, is designed to minimize off-target effects. Engaging active receptors A and B can lead to undesirable outcomes over time, and this is also applicable to GDF11. I'm confident that our approach will not introduce any extra risk to the risk-benefit profile. We will provide more clarity on this when we report our Phase III data. So far, as indicated in the TOPAZ study, we have patients who have been on treatment for four years and show a very clean safety profile. In the cardiometabolic arena, we are eager to maintain this standard, and I believe we are well positioned to demonstrate that.

Our next question comes from the line of Ernesto Rodriguez-Dumont with Cowen. Please go ahead.

Hi, thank you for taking my questions and congratulations on the progress. I just have a follow-up on the obesity program functional endpoints for regulatory purposes. Other chromatin programs that show muscle gains in other settings have hints of functional changes from those programs that could lead the way to identifying a functional endpoint for the obesity program? And then also, do you expect the therapy to be a chronic therapy in conjunction with the GLP-1, or do you expect there to be some kind of biomarker and limit to the therapy? Thank you.

Yes, I believe there are several important elements to consider regarding regulatory endpoints. We will initiate discussions with the FDA and other relevant agencies as we progress through the IND process and increase our engagement with our clinical programs. For instance, in the SMA program, we have incorporated functional measures tailored specifically to the disease. Additionally, there are various methods to evaluate GLP strength and other metrics that could demonstrate the preservation and maintenance of motor function. These are definitely worth considering. We can also assess quality of life indicators, especially since current therapies have notable gastrointestinal side effects. Our approach may contribute to weight loss in a beneficial way, potentially achieving similar results with lower dosages. We have many ideas in this area and are at the early stages of outlining the complete clinical program for registration, though we have given significant thought to myostatin and this sector already. We have numerous good ideas and more insights will come as we progress. Regarding chronic therapy, it's a fascinating topic. GLP-1 receptor agonists could lead to rapid weight regain. Considering muscle as a metabolic organ, the opportunity to restore and maintain muscle may help sustain weight loss even with reduced GLP-1 therapy. Our data indicates that we can administer apitegromab over the long term, which is supported by our experiences with patients lasting up to four years. We have much to explore in our clinical program, which is thrilling for me. I am particularly enthusiastic about the progress that Mo and his team have made with 439 since my arrival at the company as they move towards IND. It's a great advancement from our research team.

There are no further questions at this time. Mr. Jay Backstrom, I turn the call back over to you.

Yes. So, listen, thank you. Thank you for your interest. Again, just to reinforce, I'm really delighted with the work our team has done, very pleased with our progress, and I really look forward to kind of driving through the rest of this year and really running into 2024, where we have some really major milestones. So with that, we'll close the call and once again, thank you.