GMAB stock slides as Genmab scraps late-stage acasunlimab cancer therapy

GMAB stock slides as Genmab scraps late-stage acasunlimab cancer therapy

NEW YORK, December 30, 2025, 1:54 PM ET — Regular session

  • Genmab’s U.S.-listed shares fall about 3% in Tuesday trading
  • Company stops development of late-stage acasunlimab after portfolio review
  • Focus shifts to other late-stage oncology programs; 2025 guidance unchanged

Genmab A/S’s U.S.-listed shares (GMAB) fell 3.3% to $31.45 in Tuesday’s regular session. The stock traded between $31.40 and $32.06 after opening at $31.98, with about 1.9 million shares changing hands.

The move keeps attention on Genmab’s pipeline as investors reassess which late-stage assets can power growth. Dropping a late-stage program can change a biotech’s outlook quickly because those trials sit closest to potential approvals and revenue.

Genmab said on Monday it will discontinue further clinical development of acasunlimab after a portfolio review, citing a more competitive landscape. “After careful consideration, we have decided to discontinue the acasunlimab program,” Chief Executive Jan van de Winkel said. The company said the decision does not change its full-year 2025 financial guidance and it will redirect investment toward late-stage programs including EPKINLY (epcoritamab), petosemtamab and rinatabart sesutecan (Rina‑S). Business Wire

Acasunlimab was in late-stage development for solid tumors, including metastatic non-small cell lung cancer, after Genmab took full control of the program when BioNTech opted not to continue studying it in 2024. The therapy is a bispecific antibody—an engineered protein designed to bind two targets—meant to trigger an anti-tumor response by activating 4-1BB, a receptor on immune cells. Genmab highlighted other late-stage assets, including petosemtamab, which it gained through its $8 billion buyout of Merus in September, and rinatabart sesutecan, an antibody‑drug conjugate that links an antibody to a cell-killing payload and is being tested in ovarian and endometrial cancers.

For investors, a late-stage cancellation cuts future trial spending but also removes a potential source of future product revenue. That trade-off tends to show up fast in biotech share prices, even when management argues the move sharpens focus.

EPKINLY is being co-developed by Genmab and AbbVie, which share commercialization responsibilities in the U.S. and Japan while AbbVie leads commercialization elsewhere, AbbVie has said. AbbVie also said the drug has approvals in more than 65 countries for certain lymphoma indications.

That puts pressure on execution across the remaining late-stage slate, including timelines for additional studies and regulatory filings. Investors typically want visibility on when pivotal data arrive and how programs stack up against rivals in crowded oncology markets.

Genmab said the clinical profile observed to date for acasunlimab had been encouraging, but it chose to prioritize what it sees as higher-impact opportunities. Traders will watch for any further detail on how resources shift inside the pipeline and whether that accelerates the next set of readouts.

The broader question is whether the portfolio reshuffle improves returns on R&D spending without creating a gap later in the decade. In biotech, the market often punishes uncertainty about what replaces a shelved program.

Attention is also likely to turn to the company’s next financial update for clues on 2026 priorities and the cadence of late-stage milestones. Any change in spending plans or timelines can matter as much as near-term revenue, given how pipeline-driven the story is.

Shan Ahmed Khan

Shan Ahmed Khan is a senior markets reporter at TS2.tech. His coverage ranges from stocks and technology to economic developments across global markets. He worked in investment research and market analysis before becoming a financial journalist and is a graduate of the Lahore University of Management Sciences (LUMS).

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