Genmab offers $1.8bn for ADC specialist ProfoundBio

Antibody developer Genmab has made a play to boost its expertise in the scalding hot area of antibody-drug conjugates (ADCs), agreeing a $1.8 billion deal to acquire ProfoundBio.

The Danish pharma has built an extensive portfolio of approved and experimental antibody-based therapies and recorded revenues of almost $2.4 billion last year, mainly from royalties on products like Johnson & Johnson’s Darzalex (daratumumab) for blood cancers and Novartis’ multiple sclerosis therapy Kesimpta (ofatumumab).

It is the first acquisition by Genmab and comes after it ramped up its commercial operations by taking the lead on AbbVie-partnered lymphoma bispecific antibody Epkinly (epcoritamab) in both the US and Japan.

Genmab intends to pay cash for Seattle-headquartered ProfoundBio, which has three clinical-stage ADC candidates led by rinatabart sesutecan or Rina-S (PRO1184), which is phase 2 clinical testing. The drug, which targets folate receptor alpha (FRα), is being developed for solid tumours, including ovarian and endometrial cancer, with a pivotal trial in ovarian cancer due to start later this year.

Rina-S has been granted fast-track designation by the FDA for the treatment of patients with FRα-expressing high-grade serous or endometrioid platinum-resistant ovarian cancer. If approved, it would be a rival to AbbVie and Immunogen’s Elahere (mirvetuximab soravtansine), which was approved by the FDA for the treatment of platinum-resistant ovarian cancer in 2022.

Following after in ProfoundBio's pipeline are PRO1160, a CD70-directed ADC with potential in renal cell carcinoma (RCC), nasopharyngeal carcinoma (NPC), and non-Hodgkin lymphoma (NHL), and PTK7-targeting PRO1107 for solid tumours. Both are in early-stage clinical development, with initial results due later this year and in early 2025, respectively.

The ProfoundBio acquisition isn’t Genmab’s first move in the ADC category, as it provided the antibody that underpins Tivdak (tisotumab vedotin) – developed in partnership with Seagen (now part of Pfizer) – but it does represent the first major effort to build in-house capabilities.

It also comes as companies developing ADCs have become takeover and big-ticket partnership targets for big pharma groups. Pfizer’s $34 billion play for Seagen is the largest of those deals, but Bristol-Myers Squibb, MSD, AbbVie, and AstraZeneca have all been big investors in the last few years.

Genmab’s overture comes shortly after ProfoundBio raised $112 million in a Series B. The deal has been unanimously approved by the boards of both companies and is expected to close in the first half of 2024.