Genmab Shares Jump 16% as Rally Builds on Cancer Drug Wins, JPMorgan Upgrade and Head and Neck Trial Hopes

Shares of Genmab A/S jumped 16% on Wednesday, extending a powerful rally driven by a string of positive cancer trial results and a major analyst upgrade.

Genmab's U.S.-listed shares rose $7.17, or 16.05%, to $51.84 in early trading on the Nasdaq. More than 4.3 million shares changed hands. The gain lifted the Danish biotech's market value to about $31.4 billion.

The stock is up about 54% over the past 52 weeks.

Genmab had been scheduled to hold an investor update on Wednesday, according to market reports. The company has drawn growing investor attention after a series of clinical successes over the past week.

Ovarian cancer breakthrough

The rally began last week with results from RAINFOL-02, a late-stage trial of Rina-S, an antibody-drug conjugate for platinum-resistant ovarian cancer. The study enrolled 584 patients and compared Rina-S with chemotherapy chosen by doctors.

Rina-S reduced the risk of disease progression or death by 71% and cut the risk of death by 57%, according to results reported by BioSpace.

Analysts were impressed. William Blair analysts said the magnitude of the benefit "exceeds investor expectations and sets a high bar for future competition in ovarian cancer." Truist Securities analysts said the data "establish Rina-S as a potential new standard of care across broad PROC," referring to platinum-resistant ovarian cancer.

Genmab plans to discuss the results with regulators. Leerink Partners analysts expect a filing in early 2027 and a possible U.S. launch late next year.

Colorectal cancer data

On Monday, Genmab shares jumped about 13% after the company presented updated mid-stage data at the European Society for Medical Oncology Congress in Madrid for petosemtamab, a bispecific antibody, in metastatic colorectal cancer.

In 79 patients treated with petosemtamab plus chemotherapy, the response rate was 75% in first-line patients and 67% in second-line patients.

Genmab also announced a collaboration with Incyte to test Incyte's experimental KRAS G12D inhibitor in combination with petosemtamab and chemotherapy.

JPMorgan upgrade

On Tuesday, JPMorgan upgraded Genmab to "overweight" from "neutral." It raised its price target on the Copenhagen-listed shares to 3,500 Danish kroner from 2,050 kroner.

The bank said it expects positive results in November from a late-stage trial of petosemtamab in head and neck cancer, with interim data covering about 300 of 500 planned patients. It raised its peak sales forecasts to $5 billion from $2.5 billion for petosemtamab, to $4 billion for Rina-S and to $2.5 billion for Epkinly in first-line lymphoma.

JPMorgan cautioned that a failure of the head and neck trial and faster competition were key risks.

Lymphoma success

Genmab and partner AbbVie also reported that a late-stage trial of epcoritamab, sold as Epkinly, plus standard chemotherapy significantly improved progression-free survival in newly diagnosed diffuse large B-cell lymphoma. That could expand the drug's use into earlier treatment.

Acquisitions pay off

Genmab gained petosemtamab through its acquisition of Merus. Rina-S came from its earlier purchase of ProfoundBio. Analysts say the recent data suggest those deals are starting to pay off as Genmab seeks new growth drivers.

The company has relied heavily on royalties from Darzalex, the blockbuster multiple myeloma drug sold by Johnson & Johnson. Its patents will eventually expire, and investors have been watching for Genmab to build its own portfolio of wholly owned drugs.

Strong financial position

Genmab raised its 2026 financial outlook in August after revenue jumped about 25% in the first half of the year.

What to watch

Investors are now focused on the head and neck cancer trial results expected in November, regulatory filings for Rina-S and the company's third-quarter results.