Scholar Rock Wins US Patent for Apitegromab

The United States Patent and Trademark Office has granted Scholar Rock a patent for apitegromab, with add-on and combination therapies, for treating muscle conditions such as spinal muscular atrophy (SMA).

“We are delighted to have been granted this unique patent that further protects our myostatin approach to improving motor function for patients with SMA and we look forward to the top-line readout from the apitegromab TOPAZ Phase 2 trial next quarter, which will provide additional insights on its potential to help patients with Type 2 and Type 3 SMA,” Tony Kingsley, president and CEO of Scholar Rock, said in a press release.

The patent broadly covers the use of myostatin inhibitors and combination therapies related to apitegromab, add-on therapies, and combination therapy with a myostatin inhibitor and a neuronal corrector therapy — such as one boosting survival motor neuron protein levels — for the treatment of SMA types 1, 2, and 3.

Apitegromab (previously known as SRK-015) is an antibody that inhibits myostatin, a protein produced by skeletal (movement-related) muscle cells to limit muscle growth. This strategy might increase muscle mass in people with SMA, whose muscles grow progressively weaker from a loss of nerve signaling.

Apitegromab targets an inactive form of myostatin, preventing its conversion to the protein’s active form. The company expects this strategy to result in fewer side effects than conventional myostatin inhibitors.

Scholar Rock is testing apitegromab’s safety and efficacy in the ongoing Phase 2 proof-of-concept TOPAZ trial (NCT03921528).

Interim data from that study showed motor function improved among children and adults with SMA types 2 and 3 over six months of treatment, with 35% of all patients achieving a clinically significant improvement in Hammersmith scores (Revised Hammersmith Scale and the Hammersmith Functional Motor Scale Expanded).

Patients receiving a higher dose of apitegromab experienced greater score increases than those taking a lower dose.

Apitegromab appears safe and well-tolerated, with no severe or life-threatening side effects having been reported.

TOPAZ is due to end in 2023 and further efficacy and safety results are expected in June.

Scholar Rock has received similar patents from authorities in Japan and Europe.