Jay Backstrom
Analyst · Jefferies
Thank you, Carmen. Good morning, and welcome, everyone. Thank you for joining our third quarter business update. It's a very exciting time at Scholar Rock. With the success of SAPPHIRE, our Phase 3 registration study in spinal muscular atrophy and a successful financing, we have great momentum heading to the end of 2024. I'm joined on today's call by Ted Myles, our Chief Operating Officer and Chief Financial Officer. For our call this morning, I will start with the company overview, Ted will provide a financial and business update and I'll provide a few closing remarks before opening the call up for questions. As shown on Slide 6, we had another very successful quarter building on the momentum that we created throughout 2024. The dedication and commitment across the organization has been remarkable. The teams continue to execute and deliver all of our key milestones on time or ahead of schedule. For our lead program with apitegromab in spinal muscular atrophy, the clinical team did an outstanding job delivering the SAPPHIRE data with great skill, speed and high quality, enabling us to report out the successful results in early October. This flawless execution allows us to advance toward the next important milestones of submitting the BLA and MAA in Q1 of 2025 and keeps us on track to have our first commercial launch in the U.S. in Q4 2025 with Europe to follow assuming regulatory approvals. In addition for our EMBRAZE Phase 2 proof-of-concept with apitegromab, we completed enrollment ahead of schedule, positioning us to report our top line results earlier than planned, now targeting Q2 of 2025. Similarly, the research team continues to deliver a steady cadence of informative non-clinical data with SRK-439, our novel, highly selective anti-myostatin program in obesity and cardiometabolic disorders. In addition to our focused execution, we expanded our management team with the addition of Beth Shafer. Beth is an industry veteran who joined in September as Chief Business Officer to help guide our investment decisions and partnering opportunities to enable us to take full advantage of our validated platform that has produced a robust pipeline of high value potential products. Turning to Slide 7. Before I provide more detail of our third quarter results, I want to start with a reminder as to why we are here. Our purpose is to create new possibilities for those living with SMA, like [Liza], who made it clear that they want more. More means gaining muscle strength and function in order to maintain independence for basic daily activities such as feeding yourself, turning in bed or operating a motorized wheelchair, activities that can be maintained or achieved with a 1 to 2 point improvement on the Hammersmith Functional Motor Scale, a scale designed specifically for SMA. When asked what she was seeking, [Liza] made it clear, muscle, muscle is everything. Now to Slide 8. As we announced in October, our pivotal Phase 3 SAPPHIRE study met the primary endpoints with a 1.8 points improvement of apitegromab plus standard of care compared to placebo plus standard of care as measured by the gold standard SMA specific Hammersmith Functional Motor Scale at week 52. This clinically meaningful benefit was statistically significant with a P-value of 0.0192. Patients receiving apitegromab demonstrated early and increasing motor function improvement versus placebo is measured by the Hammersmith scale. With the apitegromab patients gaining function, while those receiving placebo lost function despite being on standard of care. Importantly, apitegromab demonstrated consistency of effect across doses in age groups of 2 to 21 in a broad SMA population. Further apitegromab showed transformative clinical activity with 30% of patients who were already receiving standard of care, achieving an additional 3 point or greater improvement in their Hammersmith scores. With respect to safety and tolerability, SAPPHIRE confirmed apitegromab's favorable safety profile, which was consistent with the established safety profile seen in over four years of treatment at SMA based on our Phase 2 TOPAZ study. The observed safety profile is consistent with apitegromab's highly selective approach to blocking myostatin. We are thrilled with these results and what it means for the SMA community patients, their families, caregivers and physicians. We believe these data collectively show that apitegromab has the potential to become part of a new standard of care in SMA. Turning to Slide 9 to put our results into context, it is helpful to understand the normal trajectory for those receiving standard of care treatment. Despite the availability of three approved therapies targeting the SMA protein, individuals like [Liza] are still at risk of losing function over time, given the inherent progressive nature of SMA. This was illustrated at the CureSMA meeting in June of this year. The graph represents the Hammersmith Motor Function Scores over time for the nusinersen treated patients from CHERISH, SHINE study with the orange line representing the trajectory of those randomized to nusinersen referred to as early dose group. As shown the motor function improved for the first two years after starting treatment with nusinersin, followed by a plateau where there's no further improvement motor function. After four years of treatment however, there's a progressive loss of motor function of approximately 1 point per year despite the continued treatment with this standard of care therapy. The purple shaded box represents the time period in terms of duration of nusinersin treatment that is similar to the median treatment duration of nusinersin for those enrolled in SAPPHIRE, a time period where the SAPPHIRE patients were clearly on the declining phase of their treatment journey while on standard of care. Now to take a look at how apitegromab affects motor function over time, Slide 10 displays the change from baseline and Hammersmith scores by visiting. These line graphs beautifully articulate the treatment benefit of apitegromab over the course of the treatment period. As you can see, the Hammersmith score improved in patients on apitegromab as early as eight weeks, the first post baseline assessment. By contrast, the scores decreased in those on placebo with a change from baseline of minus 1.2 points similar to the long-term data on nusinersen that indicated a loss of about 1 point per year after four years of treatment. There's early separation between apitegromab and placebo. The difference widens by the end of the treatment period underscoring the effect of apitegromab on the disease course from losing function, despite being on standard of care to gaining function by adding apitegromab. The strength of the results is illustrated by the forest plot for all of the pre-specified analyses shown in Slide 11. As shown there's consistency across analyses with all showing improvement favoring apitegromab, including across doses and across age groups. These analyses speak to the strength and the robustness of our results. Moving to Slide 12. To further underscore functional improvement, we see 30% of SAPPHIRE patients on apitegromab achieving a 3 point improvement versus 12.5% for those on placebo, this transformative magnitude of improvement is extraordinary on top of standard of care. Again, the strength and consistency of the results demonstrate the ability of apitegromab to alter the course of disease from losing function to gaining function with the potential for profound impact on the lives of those living with SMA. We believe apitegromab is suitable for chronic treatment for a broad SMA population based on the efficacy seen with SAPPHIRE with improvements seen across all age groups 2 to 21, the well tolerated safety profile with safety supported by more than four years of experience in SMA, and we are working with urgency to finalize our regulatory applications and submit the BLA and MAA in the Q1 of 2025. Now moving to our cardiometabolic program on Slide 14. The recent approvals and rapid adoption of semaglutide and tirzepatide has had very positive impact on those living with obesity. However, a key issue that has emerged is the significant loss of lean muscle mass associated with these highly effective treatments. Given the important role muscle plays in energy metabolism and glucose homeostasis, maintaining appropriate levels of lean muscle is essential to healthy living. We believe our approach to preserving lean muscle mass with our highly selective novel anti-myostatin SRK-439 when used with a GLP-1 receptor agonist can preserve lean muscle mass and promote healthy weight management. We see SRK-439 as part of the next wave of innovation in the treatment of obesity and are working to submit the IND targeted for mid-year 2025. Now to Slide 15, we designed a comprehensive non-clinical program with SRK-439 and to date we've demonstrated strong scientific rationale and promising non-clinical evidence, including demonstrating preservation of lean mass during GLP-1 receptor agonist induced weight loss, improvement in fasting glucose beyond GLP-1 receptor agonist alone, increase in lean mass and attenuation of fat mass regain following GLP-1 receptor agonist withdrawal, greater potency compared to an anti-ActRII antibody, and most recently an increase in lean mass and lowered fat mass gain following treatment with metformin and SRK-439. Turning to Slide 16, we entered into the area of obesity as we believe we have an elegant solution to preserving lean muscle mass with a potential attractive risk benefit profile for long-term healthy weight management. We have the right target, inhibition of myostatin, a negative regulator of muscle is known to promote muscle growth and function. We have a validation of our approach given the results of SAPPHIRE demonstrating improvement in motor function. And further, preserving lean mass has the potential to improve durability of weight loss. And our highly selective approach in targeting the pre and latent form of myostatin minimizes unwanted toxicities and supports the potential for a favorable benefit risk profile. I will now invite Ted to provide a financial and business update. Ted?