Capping off a busy few days in Spain, Genmab reported results from the first interim analysis of a phase 3 trial showing that adding its bispecific antibody petosemtamab to Merck & Co.'s Keytruda cut the risk of death by 50% compared with Keytruda alone in patients with PD-L1-positive recurrent or metastatic head and neck squamous cell carcinoma (HNSCC).
The results, announced Wednesday, came a day after the European Society for Medical Oncology (ESMO) congress concluded in Madrid. The late-stage LiGeR-HN1 study met both primary endpoints, demonstrating statistically significant improvements in overall survival and objective response rate with the combination compared with Keytruda alone.
Genmab acquired the immunoglobulin G1 bispecific antibody through its $8 billion acquisition of Merus last year. Petosemtamab binds both epidermal growth factor receptor (EGFR) and leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5), the latter of which is a novel oncology target.
The overall survival benefit was reflected in a hazard ratio of 0.50, while the odds of achieving an objective response were 3.17 times higher with the combination than with Keytruda alone. Genmab reported that the combination's safety profile was consistent with previous findings for the individual drugs, with no new safety signals identified.
"These topline phase 3 results represent a defining milestone for Genmab and further strengthen our conviction in petosemtamab as a potential first-in-class treatment option for patients with this difficult-to-treat cancer," Genmab CEO Jan van de Winkel, Ph.D., said in a release.
Genmab plans to discuss the results with global regulators and submit the full dataset for presentation at a future medical meeting.
Earlier this week, the company disclosed data from a midstage trial in recurrent or metastatic HNSCC showing an objective response rate of 63% among 43 evaluable patients and median progression-free survival of nine months with petosemtamab plus Keytruda.
In a note this week, William Blair analysts projected $4 billion in peak sales for petosemtamab in HNSCC alone. Genmab is also evaluating the drug in second- and third-line recurrent or metastatic HNSCC, as well as colorectal cancer, across three additional phase 3 studies.
And petosemtamab isn't Genmab's only recent success. The company also reported a phase 3 win for its antibody-drug conjugate rinatabart sesutecan in platinum-resistant ovarian cancer during the ESMO congress.