Scholar Rock recently reported financial results for the first quarter ending March 31, 2020, highlighting progress and upcoming milestones for its pipeline programs—include the SRK-015 program for spinal muscular atrophy (SMA). Scholar Rock plans to report interim efficacy, safety, pharmacokinetic (PK), and pharmacodynamic (PD) results in the fourth quarter of 2020 for patients across the three cohorts who have progressed through at least 6 months of the treatment period. This is an approximately one quarter delay compared to the previous guidance of interim 6-month results in mid-2020, due to COVID-19-related restrictions that have impacted patient access to clinical trial sites.
As of May 1, 2020, most patients have either completed or are on track to complete their 6-month visit for the interim efficacy and safety analysis. For patients who have had their 6-month visit impacted, Scholar Rock is working closely with clinical trial sites on scheduling to minimize any additional delays in dosing and assessments. Current details for the clinical trial include:
- Enrollment of the TOPAZ proof-of-concept trial was completed in January 2020. 58 patients with Type 2 or Type 3 SMA were enrolled across the three cohorts (23 patients in Cohort 1, 15 patients in Cohort 2, and 20 patients in Cohort 3).
- To date, one patient (Cohort 1) has discontinued from the trial for reasons unrelated to the study drug and which occurred prior to the COVID-19 pandemic.
- As of May 1, 2020, 41 of 57 patients have completed the 6-month visit for the interim efficacy and safety analysis, and 51 of 57 patients have completed the 5-month visit.
- Approximately 70 percent of patients are enrolled in the U.S. and the remaining 30 percent of patients are enrolled in Europe, including Italy, Spain, and Netherlands.
Top-line data for the 12-month treatment period are now expected in the first half of 2021. There may be further impacts on the timing of future doses and assessments for patients in the trial as the effects of the COVID-19 pandemic continue to evolve.
SRK-015 works by inhibiting myostatin. Myostatin is a protein that works with other proteins and hormones to help regulate muscle mass. In healthy individuals, myostatin limits muscle growth and differentiation, to prevent muscles from growing too large. For individuals affected by SMA, inhibiting this protein may combat the muscle weakness and atrophy that characterizes the disease. A Phase 1 clinical trial in healthy volunteers is ongoing. The U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation (ODD) for SRK-015 for the treatment of SMA.