Scholar Rock Books $0.6M ISEMBYLD Revenue, Sees 2027 Infusion Ramp

Scholar Rock (NASDAQ:SRRK) posted $0.6 million in third-quarter revenue from initial shipments of ISEMBYLD, its newly approved spinal muscular atrophy (SMA) treatment — and executives said insurance and reimbursement hurdles will likely push most enrolled patients' first infusions into 2027. The number is small; the timeline is the real story for anyone tracking this launch.

The U.S. Food and Drug Administration approved ISEMBYLD in September for patients ages 2 and older with SMA who are receiving an SMN2-targeted treatment (the standard-of-care gene and splice therapies). Scholar Rock estimates roughly 6,600 people in the U.S. qualify based on their current therapy.

How is demand tracking six weeks in?

Chairman and CEO David Hallal said demand has been steady across a range of patients and prescribers during the first six weeks of the launch. The company did not disclose how many patients have enrolled in its support program.

The early numbers skew broad, though:

• More than one-third of the top 140 U.S. SMA treatment centers enrolled initial patients through the end of October.
• A significant number of enrollments came from outside those centers, Hallal said.
• Patients new to ISEMBYLD outnumbered those transitioning from clinical trials and the expanded access program.
• Children formed the largest group of enrollees, with a substantial number of adults also enrolled.
• Chief Operating Officer Keith Woods said the group included patients with improving, stable and declining motor function.

Asked whether a bone fracture warning had affected demand, Hallal said it had not affected demand or prescribing patterns. That's one risk off the table, at least so far.

What's delaying the infusions?

Executives cautioned that the time from prescription to infusion can average more than 60 to 90 days early in the launch. Woods cited prior authorizations (insurer sign-offs before treatment), appeals of denials, hospital formulary approvals, and the need to use an unspecified billing code until an ISEMBYLD-specific code becomes available April 1, 2027.

Hallal said the absence of established medical policies and the drug's inclusion in payer systems were among the reasons for early denials. Woods expects the timeline to shorten as more policies are established, though prior authorizations will remain part of the process.

Access is moving: through October, Scholar Rock had reached payers covering more than 90% of U.S. covered lives. Woods highlighted published policies from Anthem and Centene — together representing 47 million covered lives — as aligned with the drug's label. The company has also won patient-by-patient approvals from commercial and government plans that have not yet issued policies.

What's happening in Europe and Japan?

Scholar Rock resubmitted its European marketing application for apitegromab — the drug's generic name, marketed as ISEMBYLD in the U.S. — in early October. President of R&D Akshay Vaishnaw said the filing includes an alternate fill-finish facility in place of Catalent Indiana, and the review is ongoing. The company expects an opinion from the European Medicines Agency's Committee for Medicinal Products for Human Use in the first half of 2027.

Woods said Scholar Rock is preparing for a potential launch in Germany later in 2027, followed by other European countries over time, subject to approval and reimbursement. In Japan, the company submitted its application in early November and received priority review; Vaishnaw noted Japan's regulator typically targets an approximately nine-month review cycle. Pending approval and a pricing and reimbursement process, Scholar Rock anticipates a launch near the end of 2027.

What about the pipeline and the balance sheet?

The company is developing a high-concentration subcutaneous version of apitegromab and plans to update investors on the development path after discussions with U.S. and European regulators. Vaishnaw said pharmacokinetic and pharmacodynamic bridging (studies showing the new formulation behaves like the old one) could be key to the regulatory case, though the final approach remains subject to those talks.

Also in motion:

• Enrollment is underway for infants and toddlers under age 2 in the Phase 2 OPAL study in SMA.
• Dosing has begun in the Phase 2 FORGE trial testing apitegromab in facioscapulohumeral muscular dystrophy, expected to enroll 60 patients.
• For the myostatin inhibitor SRK-439, Phase 1 top-line data are expected by year-end, with results to be shared in early 2027.

Chief Financial Officer Vikas Sinha reported third-quarter operating expenses of $106.6 million, including $17.9 million in noncash stock-based compensation. The company ended the quarter with $413.6 million in cash, equivalents and marketable securities.

Two more cash levers matter. In November, Scholar Rock signed a definitive agreement to sell its priority review voucher for $205 million, with cash expected at closing. Sinha said the ISEMBYLD approval also unlocked access to an additional $150 million under its existing debt facility. Management said it does not currently need to tap capital markets to fund its priorities.

The bottom line: $413.6 million in cash, a $205 million voucher sale, and $150 million in new debt capacity give Scholar Rock room to run — the constraint now is payer timelines, not money.