Scholar Rock shares climbed on September 10 after CEO David Hallal provided an update on the Company’s regulatory and commercial timeline for apitegromab, its investigational myostatin inhibitor for spinal muscular atrophy (SMA), during the Citigroup Biopharma Back to School Summit.
The U.S. Food and Drug Administration will render its decision on the biologic license application by September 30, 2026 — roughly three weeks away from the summit call. The approval would mark a significant milestone for the Cambridge-based biotech, which was founded 15 years ago and has spent approximately seven years developing apitegromab.
Hallal described apitegromab as the first and only myostatin inhibitor demonstrated to deliver statistically significant and clinically meaningful benefits in a phase III trial. The pivotal SAPPHIRE study enrolled 188 SMA patients who had been receiving SMN-targeted therapies — Spinraza or Evrysdi — for an average of five years. At the recommended dose of 10 milligrams per kilogram, patients showed a 2.2-point improvement on the Hammersmith Functional Motor Scale, and were 3.8 times more likely to achieve a 3-point or greater improvement compared with placebo.
Long-term data from the broader development program, including the TOPAZ study that enrolled children as young as 2 years old, showed a 95 percent compliance rate with up to seven years of treatment retention across approximately 250 patients.
The road to the current PDUFA date followed a protracted supply-chain dispute. In November 2025, during its Q3 earnings call, Scholar Rock announced a contract with an alternate fill-finish facility after Catalent Indiana — then owned by Novo Nordisk — became a liability. A Type C meeting with the FDA on March 3, 2026, produced what Hallal characterized as a competitive approach: the agency invited the company to resubmit its BLA using both manufacturing sites, with whichever facility enabled the fastest approval remaining in the filing. Scholar Rock resubmitted on March 31, 2026. The alternate facility underwent a re-inspection window from April 13 to April 24, and commercial manufacturing was secured there in the first half of 2026. By early August 2026, Catalent Indiana was removed as a commercial supplier.
Hallal stressed that the alternate fill-finish facility is not a boutique operation but a substantial site with an established global track record.
Commercial preparation for apitegromab is well advanced. Scholar Rock has identified 140 SMA centers of excellence across the U.S. and built a home-infusion network of roughly 10,000 nurses, alongside a patient support program called Scholar Rock Supports. Hallal noted the company aims to reach patients in approximately 50 countries, with the U.S., Europe and Japan accounting for about 30 of those markets.
Reimbursement is expected to come in stages. A miscellaneous J-code is anticipated in Q4 2026 or Q1 2027, followed by a drug-specific J-code starting in April 2027.
In Japan, the Pharmaceuticals and Medical Devices Agency agreed to accept a Japan New Drug Application — planned for submission by the end of 2026 — without requiring a local clinical trial. In Europe, Scholar Rock withdrew its marketing authorization application after regulators advised adding the alternate fill-finish facility, which had triggered multiple clock stops tied to the Catalent Indiana standoff.
Physician sentiment has shifted markedly. Among key-opinion-leader neurologists, the share saying they would offer apitegromab to all SMA patients upon approval rose from roughly 25 percent in 2025 to 42–43 percent in 2026. Surveys cited by Hallal found that 90 to 95 percent of patients consider muscle strength and motor function their top medical need, while about one-third of U.S. SMA patients receive two or more SMN-targeted therapies sequentially or concurrently. Roughly 75 percent of neurologists believe SMA should be treated by addressing both the motor neuron and the muscle — a rationale Hallal said the clinical data support, noting a shift "from a loss of motor function to a gain of motor function."
