Merus (MRUS) Leerink Global Healthcare Conference 2025 summary

Company overview and technology

• Focuses on oncology with multiple clinical assets and partnerships based on unique multispecific antibody technology.

• Bispecific antibodies are engineered to mimic monoclonal antibodies, enabling established manufacturing and process efficiencies.

• Five drugs have entered the clinic; three have shown significant clinical activity, including MCLA-129 and Bizengri.

Petosemtamab clinical development and data

• Petosemtamab, an EGFR x LGR5 bispecific, demonstrated 36% response rate in second-line head and neck cancer versus 13% for cetuximab.

• Combination with pembrolizumab in first-line head and neck cancer showed a 67% response rate in 45 patients, compared to 19%-25% for pembrolizumab alone.

• Phase III registration trial for petosemtamab is underway, with all patients dosed by March 6, 2024.

• Median time to response is 1.9 months; updated efficacy, safety, and durability data expected at a medical conference in the first half of 2024.

Competitive landscape and regulatory strategy

• Main competitors in first-line head and neck cancer include zanzalintinib (Exelixis), Akeso (China), and Bicara's BCA101 for HPV-negative subset.

• Petosemtamab shows activity in both HPV-positive and HPV-negative populations, unlike cetuximab.

• Regulatory discussions focus on all-comer populations; HPV status is not a limiting factor for trial design or approval.

• Statistical plan includes dual primary endpoints: overall response rate (for potential accelerated approval) and overall survival.

• FDA's Project FrontRunner supports accelerated approval based on response rate with confirmation by survival data.