petosemtamab (MCLA-158)

P1/2, N=360, Recruiting, Merus N.V. | Trial completion date: Jun 2024 --> Jun 2025 | Trial primary completion date: Jun 2023 --> Jun 2024

1 esophageal cancer pt died due to unrelated G5 GI bleeding. Petosemtamab demonstrated promising clinical efficacy among patients with pretreated GEA having EGFR gene amplification and/or overexpression, with a manageable safety profile.

Pts received a median of 2 (range 1-4) lines of prior systemic therapy, including anti-PD-1/PD-L1 in 96% of pts and platinum-based chemotherapy in 92% of pts; 2 pts received prior cetuximab. Petosemtamab demonstrates promising clinical efficacy with a manageable safety profile in pretreated HNSCC pts. Further clinical development in HNSCC is planned with petosemtamab monotherapy and in combination with SOC.

P1/2, N=360, Recruiting, Merus N.V. | Unknown status --> Recruiting | Phase classification: P1 --> P1/2 | N=120 --> 360 | Trial completion date: Jan 2021 --> Jun 2024 | Trial primary completion date: Jan 2021 --> Jun 2023

Our drug discovery strategy resulted in the generation of MCLA-158, a bAb that specifically triggers epidermal growth factor receptor degradation in leucine-rich repeat-containing G-protein-coupled receptor 5-positive (LGR5+) cancer stem cells but shows minimal toxicity toward healthy LGR5+ colon stem cells. MCLA-158 exhibits therapeutic properties such as growth inhibition of KRAS-mutant colorectal cancers, blockade of metastasis initiation and suppression of tumor outgrowth in preclinical models for several epithelial cancer types.

Metastatic CRC pts progressing after oxaliplatin, irinotecan and fluoropyrimidines, and EGFR monoclonal antibodies if RASwt, received MCLA-158 IV every 2 weeks (q2w; 4-week cycle) in a phase I study. Dual EGFR/LRG5 blockade with MCLA-158 was well tolerated, and the RP2D was 1500 mg IV q2w. Enrollment of pts with gastric and other non-CRC cancers at the RP2D continues in the expansion phase.