Scholar Rock, a clinical-stage biopharmaceutical company focused on the treatment of serious diseases in which protein growth factors play a fundamental role, today highlighted key accomplishments of the past year and announced R&D priorities for 2020. Below please find a community statement from Scholar Rock specifically discussing SRK-015.
Dear SMA Community,
We at Scholar Rock are deeply motivated by the SMA community and are excited to be developing and investigating SRK-015* for the treatment of SMA. We are grateful for your continued support and we believe that SRK-015 has the potential to be the first muscle-directed therapy to treat SMA.
It is exciting to share that we have now completed enrollment of the TOPAZ Phase 2 proof-of-concept trial. Achieving this milestone is an important step towards expeditiously obtaining initial insights on the safety and efficacy of SRK-015, allowing us to evaluate whether treatment with SRK-015 improves motor function in people with SMA. These trial results will inform and guide decisions around our broader development plans for SRK-015 in SMA, including future studies. It is our goal to develop SRK-015 for the broadest group of individuals with SMA that is supported by scientific and clinical data. The SRK-015 development program, including the design of the TOPAZ trial, continues to be a collaborative process that incorporates feedback from the patient advocacy community (including Cure SMA and the SMA Foundation), physicians, physical therapists, scientists, and regulatory authorities.
TOPAZ will evaluate the safety and efficacy of SRK-015 dosed intravenously every 4 weeks over a 12-month treatment period. The trial has completed enrollment across three cohorts:
- Cohort 1 enrolled individuals between ages 5 and 21 years with ambulatory Type 3 SMA. All are treated with 20 mg/kg of SRK-015 every 4 weeks as monotherapy or in conjunction with an approved SMN upregulator therapy. The primary objectives of the cohort are to assess safety and the mean change from baseline in Revised Hammersmith Scale (RHS) over 12 months of treatment. Key secondary assessments include the proportion of patients attaining various thresholds of change from baseline in RHS and change from baseline in a 6-minute walk test (6MWT).
- Cohort 2 enrolled individuals between ages 5 and 21 years with Type 2 or non-ambulatory Type 3 SMA and who are already receiving treatment with an approved SMN upregulator. All are treated with 20 mg/kg of SRK-015 every 4 weeks in conjunction with an approved SMN upregulator therapy. The primary objectives of the cohort are to assess safety and the mean change from baseline in Hammersmith Functional Motor Scale Expanded (HFMSE) over 12 months of treatment. Key secondary assessments include the proportion of patients attaining various thresholds of change from baseline in HFMSE and change from baseline in Revised Upper Limb Module (RULM).
- Cohort 3 enrolled individuals with Type 2 SMA who are at least 2 years of age and initiated treatment with an approved SMN upregulator before 5 years of age. Individuals were randomized to receive either 2 mg/kg or 20 mg/kg SRK-015 every 4 weeks to evaluate the effects of SRK-015 in the setting of early intervention with an SMN upregulator therapy. The primary objectives of the cohort are to assess safety and the mean change from baseline in HFMSE over 12 months of treatment. Key secondary measures include the proportion of patients attaining various thresholds of change from baseline in HFMSE and change from baseline in RULM.
The results of a November 2019 planned preliminary pharmacokinetic (PK) and pharmacodynamic (PD) analysis from 29 individuals in the TOPAZ trial were consistent with robust target engagement in individuals with SMA. No clinically significant safety signals had been observed in TOPAZ as of the data cutoff for the preliminary PK/PD analysis.
Completing enrollment in TOPAZ keeps us on track to report interim safety and efficacy results at 6 months of treatment for all three fully enrolled cohorts in mid-2020, with topline results for the 12-month treatment period expected beginning in the fourth quarter of 2020 and into the first quarter of 2021.
Scholar Rock will keep the SMA community updated around our progress and plans for the development of SRK-015 by updates provided through the patient organizations. Thank you again to everyone across the scientific, medical, and SMA community for your contributions and continued support towards this important mission of advancing the SMA treatment paradigm!
The Scholar Rock Team
Scholar Rock, Inc.
Cambridge, MA 02139
*Note: SRK-015 is an investigational product candidate that is currently being evaluated in a clinical trial. SRK-015 has not been approved by the U.S. Food and Drug Administration (FDA) or any other health authority, and the safety and effectiveness of this molecule have not been established.