Scholar Rock (SRRK) Jefferies Global Healthcare Conference summary

Lead program and clinical milestones

• Phase III SAPPHIRE study in SMA completed enrollment; results expected in Q4 this year, seen as a major catalyst.

• Proof-of-concept obesity study with apitegromab opened ahead of schedule, aiming to show preservation of lean muscle mass with GLP-1 therapies.

• SRK-439, designed for cardiometabolic use, advancing toward IND with expected opening next year.

• Data from SRK-439 to be featured at the American Diabetes Association in coming weeks.

• SMA program design informed by prior proof-of-concept and high retention in ongoing therapy.

Scientific rationale and competitive landscape

• Selective myostatin inhibition aims to preserve lean muscle during weight loss, addressing 20–40% muscle loss seen with current therapies.

• Approach avoids activin pathway to minimize toxicity, as activin blockade linked to adverse effects like nosebleeds and mouth ulcers.

• Non-clinical models show comparable efficacy to activin-targeting strategies at lower doses, supporting benefit-risk profile.

• Functional and metabolic benefits of muscle preservation expected to be more evident with long-term, chronic therapy.

• Study population for SMA is more homogeneous, focusing on non-ambulatory children aged 2–21, which may improve outcome predictability.

Study design and future data readouts

• Obesity proof-of-concept trial: 100 patients randomized to GLP-1 therapy with or without apitegromab, 24-week endpoint to assess lean muscle mass preservation.

• Exploratory endpoints include hemoglobin A1c and functional measures to inform future clinical benefit.

• SRK-439 designed for low-volume subcutaneous dosing, suitable for larger obesity populations.

• Next anti-myostatin obesity data readout expected by mid-2025, ahead of some competitors.