Petosemtamab granted 2nd Breakthrough Therapy designation by FDA

The US Food and Drug Administration (FDA) has granted Breakthrough Therapy designation (BTD) to Dutch clinical-stage drug developer Merus (Nasdaq: MRUS), for its petosemtamab in combination with pembrolizumab for the first-line treatment of adult patients with recurrent or metastatic programmed death-ligand 1 (PD-L1) positive head and neck squamous cell carcinoma (r/m HNSCC) with combined positive score (CPS) ≥ 1.

This second BTD designation follows the initial receipt of BTD and Fast Track designation for petosemtamab for the treatment of patients with r/m HNSCC whose disease has progressed following treatment with platinum-based chemotherapy and an anti-programmed cell death protein 1 (anti-PD-1) antibody announced in May 2024 and August 2023, respectively, said Merus, whose shares rose more than 5% to $42.27 following the announcement yesterday.

The BTD is supported by updated data from the ongoing Phase I/II open-label, multicenter trial evaluating petosemtamab in combination with pembrolizumab in first line HNSCC expressing PD-L1 (CPS≥1) (NCT03526835). Data for this cohort was initially presented at the American Society of Clinical Oncology (ASCO) Annual Meeting 2024, which demonstrated a 67% response rate among 24 evaluable patients.