On Oct. 28, Genmab reported that its bispecific antibody petosemtamab, combined with Merck's Keytruda, met both primary endpoints in a Phase 3 trial in head and neck cancer.
The trial, called LiGeR-HN1, enrolled 699 patients with recurrent or metastatic head and neck squamous cell carcinoma whose tumours express PD-L1. At the first interim analysis, the combination cut the risk of death by 50% compared with Keytruda alone.
LiGeR-HN1 at the first interim analysis
| Label | Value |
|---|---|
| Hazard ratio for overall survival (95% CI 0.37–0.67) | 0.50 |
| Odds of response vs. Keytruda alone (95% CI 2.06–4.89) | 3.17x |
| Patients enrolled | 699 |
Both results had p<0.0001. Median survival and response rates by arm have not been released.
What the trial showed, and what Genmab hasn't released yet
Overall survival and objective response rate were co-primary endpoints, and the combination hit both. An independent data monitoring committee reviewed the interim results.
Genmab said the combination was generally well tolerated and that no new safety signals appeared. It has not released median survival, response rates for each arm or detailed side-effect data. Those will come at a medical meeting Genmab hasn't named yet.
For context, J.P. Morgan noted the day before the readout that Keytruda alone produced a 17% response rate in its own pivotal trial, KEYNOTE-048, and said it expected 40% or more for the combination.
These topline Phase 3 results represent a defining milestone for Genmab
Jan van de Winkel, CEO, Genmab
Why Genmab paid $8 billion for a single antibody
Genmab agreed to buy Merus, petosemtamab's developer, in September 2025 for about $8 billion in cash. It closed the deal on Dec. 12, 2025, funding it with cash on hand and $5.5 billion of new borrowing, according to its half-year report.
The reason is Darzalex. Genmab invented the multiple myeloma drug and earns royalties on Johnson & Johnson's sales, and those royalties still make up most of its revenue.
Genmab's revenue, first half of 2026
| Label | Value | Share of total |
|---|---|---|
| Darzalex royalties | $1,306M | 63.7% |
| Everything else | $745M | 36.3% |
| Total revenue | $2,051M |
Darzalex royalties grew 20% year on year, but they end when the drug's protection expires.
Darzalex royalties brought in $1.31 billion in the first half of 2026, about 64% of Genmab's $2.05 billion in revenue. Royalties like these stop when the drug's patents and contracts run out, so Genmab has been building a pipeline it owns outright.
Investors priced the result in a single day
Genmab's US-listed shares rose 28% on Oct. 28, and its Copenhagen shares gained 29%, according to Clinical Trials Arena.
Genmab Nasdaq share price, closing
| Label | Value |
|---|---|
| Oct. 27, 2026 (before the readout) | $44.67 |
| Oct. 28, 2026 (readout day) | $57.29 |
A 28.25% gain. Copenhagen shares rose 29.06% to DKr3,868.
Analysts had already been raising their numbers. On Oct. 27, J.P. Morgan doubled its peak-sales estimate for petosemtamab to $5 billion, with $3.5 billion from head and neck cancer and $1.6 billion from colorectal cancer, where Phase 3 trials are under way.
Competition is close behind
Genmab isn't alone in this market. Johnson & Johnson presented positive data for its Rybrevant Faspro combination in recurrent or metastatic head and neck cancer at the ESMO congress three days before Genmab's readout.
Petosemtamab has two FDA Breakthrough Therapy designations, one for this first-line setting with Keytruda and one for patients whose disease has progressed after chemotherapy and anti-PD-1 treatment. Those designations can speed a review.
What to watch next
- The full LiGeR-HN1 data, including median survival and response rates, at a future medical meeting.
- Filing plans. Genmab says it will engage regulators worldwide but hasn't given a timeline.
- Genmab's third-quarter results, where investors will look for launch spending plans and any update on Darzalex royalty timing.
