With new data on petosemtamab set to be presented at the European Society for Medical Oncology Asia Congress, Merus believes it has a potential new standard of care for head and neck squamous cell carcinoma on its hands.
The latest update comes from an initial expansion cohort and a new dose-comparison cohort in a phase 2 study of petosemtamab. The trial enrolled previously treated patients with recurrent/metastatic head and neck squamous cell carcinoma (HNSCC) and tested the drug as a monotherapy.
“Petosemtamab 1500 mg monotherapy continues to demonstrate consistent, durable, and clinically meaningful efficacy in 2L+ r/m HNSCC, underscoring its potential to become a new standard of care,” chief medical officer Fabian Zohren, M.D., Ph.D., explained in a press release.
Compared with a prior presentation at the American Association for Cancer Research meeting in 2023, the ESMO Asia Congress data drop features about 9 months of additional follow-up. As of the newer cutoff date Nov. 6, 2023, investigators recorded an overall response rate of 40.4% among 47 evaluable patients. One patient's response—confirmed after the cutoff—suggests a response rate of about 43%, according to a note from Leerink Partners analysts.
The confirmed response rate in the latest presentation is up from the 37% number shared at AACR last year.
In the new presentation, among responders, the median duration of response was 7.2 months. Median overall survival came in at 12.5 months and median progression-free survival was 5.1 months, according to Merus.
All told, the data reinforce the candidate's “best-in-disease profile” and should boost confidence in the company's ongoing phase 3 studies, William Blair analysts wrote in a note to clients.
The company’s December 7 presentation will include interim data from a later cutoff date with additional patients evaluable for response and “more mature duration of treatment information,” Merus noted in its release. The drugmaker is also separately testing the drug as a first-line treatment for the disease alongside Merck’s Keytruda.
Along with the data drop, Merus announced a license agreement that gives Partner Therapeutics the U.S. commercialization rights to its NRG1 fusion-positive cancer treatment zenocutuzumab. Merus had long been searching for a commercialization partner and will receive an undisclosed upfront payment through the exchange.
The deal also features potential milestone payments and high single-digit to low double-digit royalty payments based on annual net sales of the drug, which is currently under review at the FDA.
Partner, which is “grateful to Merus for their development of Zeno,” believes the drug candidate could fill an unmet need for patients with NRG1+ non-small cell lung and pancreatic cancer and may offer a “sustainable improvement” over other therapies on the market, president and chief operating officer, Sarah Kurz, said in a press release.