Akshay Vaishnaw
Analyst · Evercore
Thanks, David, and good morning, everybody. We're very pleased with advancements in our world-leading anti-myostatin pipeline during the first quarter. Turning first to apitegromab for children and adults with SMA. We're delighted to share that the FDA has accepted the apitegromab BLA. As a reminder, the BLA was resubmitted in alignment with the agency to include both Catalent Indiana and a second U.S.-based fill-finish facility. The approach provides Scholar Rock with 2 independent path to apitegromab approval by the PDUFA action date of September 30. We're gratified by the agency's continued support since the CRL last September from the constructive and collaborative in-person Type A meeting in November to the early March Type C meeting and the current acceptance of the BLA. Throughout, the agency has appreciated the high unmet need in the SMA community, and we now look forward to the final steps in the U.S. regulatory process. Reflecting the agency's vigorous efforts, we were pleased most recently with the timing of the FDA's unannounced reinspection of Catalent Indiana. For FDA guidelines, the agency now has up to 90 days to classify the status of the facility. I'd now like to turn to our second fill-finish facility, where we continue to make meaningful progress. As David noted, the apitegromab drug product required for FDA data review and potential approval has been filed, and we expect to have ample commercial apitegromab from the facility in early Q3 ahead of the September PDUFA date. Based on the significant progress at both facilities, we anticipate approval of apitegromab for children and adults with SMA, which could be supported by either or both facilities by the end of the third quarter. Turning now to Europe. Our MAA for apitegromab for the treatment of children and adults with SMA continues to progress well through EMA review. As evidence of the progress, we have planned to be with the EMA recently for an oral explanation meeting. However, because we and the EMA were able to align prior to the scheduled meeting, we mutually agreed that the oral explanation was no longer necessary. As we highlighted previously, approval in Europe also requires FDA clearance for the Catalent Indiana facility. Based on our discussions with EMA, they're aware of the progress at Catalent Indiana and are comfortable with the review time line that accounts for the FDA's classification as site. We continue to be very pleased with how the review is progressing, and we anticipate a CHMP opinion in the middle of the year. Turning to our pipeline. Let me start with the Phase II OPAL trial. We continue to enroll and dose patients in this study, which is evaluating apitegromab in infants and toddlers under the age of 2. As a reminder, this trial is enrolling participants who have been treated with an SMN1-targeted gene therapy, or who are receiving ongoing treatment with an SMN2-targeted therapy. This study is important because it is anticipated to expand the impact of apitegromab to the full spectrum of patients, including those treated with Zolgensma. In addition, we believe early intervention with apitegromab could support muscle during a critical early development phase, potentially improving motor outcomes in the youngest of patients with SMA. Turning now to our next indication for apitegromab, facioscapulohumeral muscular dystrophy or FSHD. FSHD is a rare, devastating neuromuscular disease with significant unmet need. More than 30,000 patients are diagnosed in the U.S. and Europe alone, and there are no approved therapies. We prioritized FSHD as the next indication for apitegromab for 3 key reasons: First, the significant unmet need; second, the compelling preclinical data from the gold standard FLExDUX4 mouse model that provides mechanistic rationale for apitegromab in FSHD. And finally, as shown on Slide 11, data from randomized studies in FSHD, which suggests muscle mass can increase and has the capacity to show functional benefit. For example, in studies of either rigorous physical therapy or treatment with anabolic agents, patients with FSHD demonstrated increases in lean mass and muscle function. These data suggest that apitegromab as a monotherapy may have the potential to bring important benefit to FSHD patients. We're very pleased with the progress of activities to support the initiation of our Phase II study called FORGE in the middle of this year. Enrollment will commence soon in this randomized, double-blind, placebo-controlled trial, which has a sample size of 60 patients. We're also advancing 2 additional programs in our world-leading anti-myostatin pipeline, a subcutaneous formulation of apitegromab and SRK-439. In our subcutaneous apitegromab program, we showed some very exciting data from a Phase I study in January, which demonstrated that subcu apitegromab appears to have favorable bioavailability and a pharmacodynamic profile comparable to IV administration. Additional development activities are ongoing, and we continue to plan for engagements with U.S. and European regulators later this year following approval of apitegromab. Turning now to SRK-439, our high potency, high affinity subcutaneously administered myostatin inhibitor, which we discovered by leveraging our world-leading expertise. We're very excited about this program and dosing in our Phase I healthy volunteer study is progressing well. We expect to have top line data from this study later this year. In closing, we're executing with urgency to bring apitegromab to children and adults with SMA, whilst in parallel working to maximize our impact for patients with apitegromab and our world-leading anti-myostatin pipeline across a range of rare devastating neuromuscular diseases. With that, I'll now turn the call over to Keith to discuss our commercial launch preparations. Keith?