Genmab A/S (NASDAQ:GMAB) stock shot to a 52-week high on Wednesday after the Danish biotech delivered positive topline findings from its global Phase 3 LiGeR-HN1 clinical trial. The study evaluated petosemtamab, an investigational IgG1-bispecific antibody that targets EGFR and LGR5.

Petosemtamab Cuts Risk Of Death In Head And Neck Cancer Study

The trial tested petosemtamab combined with pembrolizumab against pembrolizumab alone in patients with first-line PD-L1 positive recurrent or metastatic head and neck squamous cell carcinoma.

An independent data monitoring committee reviewed the first interim analysis and confirmed that the petosemtamab regimen met its dual primary endpoints.

The combination produced a statistically significant and clinically meaningful improvement in overall survival, cutting the risk of death by 50% compared to pembrolizumab monotherapy. It also delivered a significantly superior objective response rate, hitting both key clinical milestones regardless of HPV status.

Patients tolerated the combination well, with an overall safety profile consistent with previously reported data for petosemtamab and pembrolizumab individually. The interim review identified no new safety signals.

Global Regulatory Plans And Late-Stage Pipeline Expansion

Following the outcome, Genmab plans to engage global regulatory authorities and present comprehensive trial results at a future medical conference.

Beyond LiGeR-HN1, Genmab is evaluating petosemtamab across several other pivotal Phase 3 trials. These include the LiGeR-HN2 study in second- and third-line recurrent or metastatic head and neck cancer, as well as the LiGeR-CRC1 and LiGeR-CRC2 studies in previously treated, recurrent, unresectable or metastatic colorectal cancer.

Analyst Emphasizes Substantial Peak Sales Opportunity

William Blair wrote, "While specific details, including median OS, ORR, and PFS, remain to be seen, an OS HR of 0.50 at the first interim analysis is an exceedingly positive topline outcome and, in our view, meaningfully strengthens the case for petosemtamab + Keytruda as the new standard-of-care regimen in 1L PD-L1+HNSCC."

William Blair reiterated its Outperform rating. Analyst Matt Phipps emphasized that the convincing clinical data supports upside to William Blair's existing $8 billion peak revenue forecast.

The analyst also pointed to a significant commercial market opportunity in colorectal cancer following favorable Phase 2 trial outcomes presented at the ESMO conference.

GMAB Price Action: Genmab shares were up 30.79% at $58.42 at the time of publication on Wednesday. The stock is trading at a new 52-week high, according to market data.