FDA's Busy September: Key Decisions on Cancer, SMA, and Multiple Sclerosis Therapies

The U.S. Food and Drug Administration (FDA) is set for a busy second half of September, with several high-profile decisions expected across various therapeutic areas. From potential approvals for new formulations of blockbuster drugs to novel treatments for rare diseases, the coming weeks could significantly impact the pharmaceutical landscape.

Merck's Subcutaneous Keytruda Formulation Awaits Verdict

On September 23, the FDA is expected to decide on Merck's application for a subcutaneous version of its blockbuster PD-1 inhibitor, Keytruda. This new formulation, if approved, would be applicable across more than 40 previously approved indications for the biologic.

The subcutaneous version combines Keytruda with Alteogen's berahyaluronidase alfa, allowing for under-the-skin delivery. Phase III data from November last year demonstrated that this formulation can match the efficacy of its intravenous counterpart as a first-line treatment for metastatic non-small cell lung cancer.

Approval of this new formulation could be crucial for Merck as Keytruda approaches its patent cliff in 2028. The subcutaneous version may help the company maintain its market dominance in the face of potential biosimilar competition.

Advancements in Spinal Muscular Atrophy Treatment

Two significant decisions for spinal muscular atrophy (SMA) treatments are anticipated this month. By September 22, the FDA will rule on Biogen's application for a higher-dose formulation of Spinraza. The proposed regimen includes a 28-mg maintenance dose, with a loading schedule of two 50-mg intrathecal injections 14 days apart, compared to the current 12-mg dosing.

Biogen's application is supported by data from the Phase II/III DEVOTE study, which showed significantly better improvements in motor skills with the higher-dose regimen compared to a sham control.

On the same day, Scholar Rock expects a verdict on its anti-myostatin monoclonal antibody, apitegromab. If approved, it would become the first muscle-targeted treatment for SMA patients. The Phase III SAPPHIRE study demonstrated significant and clinically meaningful improvements in motor function compared to placebo, with effects apparent as early as eight weeks.

Sanofi's Brain-Penetrant BTK Inhibitor for Multiple Sclerosis

Sanofi awaits an FDA decision on September 28 for tolebrutinib, a BTK blocker proposed to treat non-relapsing secondary progressive multiple sclerosis and delay disability accumulation in adult patients. If approved, tolebrutinib would be the first brain-penetrant BTK inhibitor for this form of multiple sclerosis.

The application is supported by data from the Phase III HERCULES study, which showed a 31% delay in the time to onset of six-month confirmed disability progression compared to placebo. However, it's worth noting that two other Phase III trials, GEMINI 1 and GEMINI 2, missed their primary endpoint of improvements in relapse rates.