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Genmab's head and neck cancer drug cuts death risk in half in key trial

Genmab's head and neck cancer drug cuts death risk in half in key trial

New Capabilities

Petosemtamab plus Keytruda beat Keytruda alone in first-line treatment; shares hit a record and the stock added more than $10 billion in market value in a week.

October 30th, 2026: Genmab shares extend record run; weekly gain tops $10 billion

Overview

Updated Nov 1

Genmab's experimental head and neck cancer drug, petosemtamab, cut the risk of death in half when added to Merck's Keytruda in a late-stage trial. Shares hit a record on October 28, the company's third late-stage win in quick succession. Analysts at William Blair called the data 'exceedingly positive.'

Genmab is working to replace royalty income from Johnson & Johnson's Darzalex, which faces patent expiry. Petosemtamab, acquired with Merus for $8 billion in 2025, is its largest bet on that future. Genmab plans to share full results with regulators and at a future medical meeting; no date has been given.

Why it matters

If petosemtamab wins approval, Genmab turns expiring Darzalex royalties into its own blockbuster and resets first-line head and neck cancer care.

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Key Indicators

50%
Reduction in risk of death
Petosemtamab plus Keytruda vs Keytruda alone in first-line head and neck cancer (hazard ratio 0.50). Genmab says the benefit held regardless of HPV status.
$7B+
Market value added in one day
Genmab's market value rose by more than $7 billion on the trial results, per BioPharma Dive.
21%
Peak one-day gain
Shares rose as much as 21% in Copenhagen on Oct 28, per Bloomberg. Other reports put early gains as high as 29%.
3
Consecutive Phase 3 wins in October 2026
Epkinly, rinatabart sesutecan, and petosemtamab all hit trial goals within weeks.

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People Involved

YW
Yaron Werber
Equity analyst at TD Cowen
Covering Genmab after the LiGeR-HN1 readout
MP
Matt Phipps
Analyst at William Blair
Tracking Genmab's late-stage pipeline

Organizations Involved

Genmab
Genmab
Biopharmaceutical company
Danish drugmaker pushing three drugs through late-stage trials

Copenhagen-based biotech building a pipeline to replace royalties from Johnson & Johnson's Darzalex.
ME
Merus
Biopharmaceutical company (acquired)
Wholly owned by Genmab after $8 billion deal

Dutch biotech that developed petosemtamab, a bispecific antibody targeting EGFR and LGR5.
Johnson & Johnson
Johnson & Johnson
Pharmaceutical company
Holds commercial rights to Darzalex; competes in head and neck cancer

Pharmaceutical giant that commercializes Darzalex and pays Genmab royalties facing patent expiry.

Timeline

2024 October 2026

8 events Latest: October 30th, 2026 · 1 week ago
Tap a bar to jump to that date

  1. Genmab shares extend record run; weekly gain tops $10 billion

    Latest Market

    Bloomberg reported that the two positive late-stage updates added the equivalent of more than $10 billion in market value over the week.

  2. Genmab hits record valuation

    Market

    Market value rose by more than $7 billion on the trial results, per BioPharma Dive, as shares held at records.

  3. Genmab announces head and neck cancer win

    Clinical data

    Petosemtamab plus Keytruda cuts death risk 50% in first-line head and neck cancer; shares rise as much as 21% in Copenhagen.

  4. Epkinly succeeds in lymphoma trial

    Clinical data

    With partner AbbVie, blood cancer drug Epkinly hits its goal in a Phase 3 frontline diffuse large B-cell lymphoma trial.

  5. Ovarian cancer drug hits trial goal

    Clinical data

    Rinatabart sesutecan meets its endpoint in a late-stage ovarian cancer study.

  6. LiGeR-HN1 enrollment expanded

    Trial update

    Genmab upsizes the LiGeR-HN1 head and neck cancer trial, stirring analyst concerns about the outcome.

  7. Genmab completes $8B Merus deal

    Acquisition

    Genmab acquires Dutch biotech Merus, adding bispecific antibody petosemtamab.

  8. Genmab buys ProfoundBio

    Acquisition

    Genmab acquires startup ProfoundBio, gaining the antibody-drug conjugate rinatabart sesutecan.

Scenarios

1

Genmab wins FDA approval for petosemtamab in first-line head and neck cancer

Likely Resolves by End of 2027

Discussed by: Truist analysts, who moved a modeled approval from 2028 to a possible 2027

Genmab plans to share LiGeR-HN1 results with regulators and seek approval based on survival and response data. A first-interim overall survival win on a Keytruda backbone is a strong basis for filing, and Truist already pulled its approval estimate forward by a year.

2

Full LiGeR-HN1 data disappoint on survival magnitude

Uncertain Resolves by Q2 2027

Discussed by: Analysts noting the open-label design and missing medians (ApexOnco, Biobucks newsletter)

Genmab has not released median survival, absolute response rates, or grade 3-plus toxicity figures. A full dataset presented at a 2027 medical meeting showing median overall survival well below the 28.2 months seen in Phase 2 would weaken the approval case and the blockbuster sales projection.

3

A rival regimen reaches first-line head and neck cancer first

Unlikely Resolves by End of 2027

Discussed by: Bicara and Johnson & Johnson competitors noted by ApexOnco

J&J's Rybrevant combination succeeded in recurrent and metastatic head and neck cancer days earlier, and Bicara's ficerafusp alfa targets HPV-negative disease with a Phase 3 readout expected in mid-2027. If a rival wins approval in first-line before petosemtamab, Genmab's addressable market narrows.

Historical Context

3 moments from history that rhyme with this story — and how they unfolded.

2006

Cetuximab approval (2006)

The FDA approved cetuximab (Erbitux), the first targeted therapy for head and neck squamous cell carcinoma. It blocks the EGFR protein and became a standard treatment for years, though responses were modest and it never paired cleanly with immunotherapy.

Then

Cetuximab-based chemo became the default first-line treatment for recurrent and metastatic disease.

Now

It remained the only targeted head and neck cancer therapy until immunotherapy arrived over a decade later.

Why this matters now

Petosemtamab also targets EGFR but adds a second target, LGR5, and showed far stronger efficacy alongside Keytruda than cetuximab ever did.

2019

Keynote-048 trial (2019)

The Keynote-048 trial made pembrolizumab (Keytruda) a first-line standard for recurrent or metastatic head and neck cancer, replacing cetuximab-based chemo. Keytruda monotherapy became the first-line benchmark for PD-L1-positive disease.

Then

Keytruda became the backbone of first-line treatment in this disease.

Now

It set the benchmark every new regimen now has to beat, and the bar for combination trials.

Why this matters now

Petosemtamab's LiGeR-HN1 trial used Keytruda as both the backbone and the comparison arm, measured against this exact benchmark.

2015

Darzalex transformation (2015)

Genmab's daratumumab (Darzalex) won FDA approval for multiple myeloma in 2015, with Johnson & Johnson as commercial partner. The drug turned Genmab from an R&D shop into a royalty-driven company.

Then

Darzalex became a multiple myeloma standard and Genmab's main income source.

Now

The royalty stream is now facing patent expiry, forcing Genmab to build its own product portfolio.

Why this matters now

Petosemtamab, Epkinly, and rinatabart sesutecan are the drugs meant to replace those Darzalex royalties.

Sources

(13)
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BioPharma Dive Clinical Trials Arena ApexOnco Biobucks Bloomberg Law SquawkNews TradingKey MedWatch Bloomberg BioSpace BioWorld Life Science Daily Bloomberg