AbbVie Inc. has filed a complaint in the U.S. District Court for the Western District of Washington against Genmab A/S and its recently acquired subsidiary ProfoundBio, alleging misappropriation of trade secrets related to antibody-drug conjugate (ADC) technology. The lawsuit, filed on March 22, 2025, also names ProfoundBio's U.S. and Chinese entities along with former AbbVie employees as defendants.
The legal dispute centers on technology used in rinatabart sesutecan (Rina-S), a clinical-stage cancer therapeutic currently in Phase 3 development. Genmab has issued a strong statement categorically refuting the allegations and announcing its intention to "vigorously defend" against AbbVie's claims.
The Technical Dispute
According to court documents, AbbVie alleges that the defendants misappropriated trade secrets specifically relating to the use of disaccharides to improve the hydrophilicity of drug-linkers in antibody-drug conjugates. This technology is reportedly incorporated into Rina-S and other ADC pipeline products developed by ProfoundBio, which Genmab acquired in May 2024.
AbbVie is seeking both monetary damages and broad injunctive relief. Notably, the pharmaceutical giant is not asserting any patent rights in this case, and Genmab claims that to its knowledge, AbbVie has not pursued development of products incorporating the alleged trade secrets in question.
In its response, Genmab pointed out that this lawsuit appears to be part of a pattern, describing it as "yet another lawsuit among multiple recent lawsuits filed by AbbVie against competitors alleging misappropriation of its trade secrets by former AbbVie employees."
Rina-S: The Drug at the Center of the Dispute
Rinatabart sesutecan is a folate receptor-alpha (FRα)-targeted, topoisomerase I (Topo1) antibody-drug conjugate currently in Phase 3 clinical development for ovarian cancer and other FRα-expressing solid tumors. The drug's design includes several technical innovations:
- A proprietary antibody targeting FRα
- A specialized linker combining polyethylene glycol (PEG) with sorbitol
- A homogenous drug-to-antibody ratio (DAR) of 8
- Exatecan payload, a second-generation topoisomerase I inhibitor
Genmab claims Rina-S has potential advantages over current standard treatments, including AbbVie's Elahere, particularly in addressing platinum-resistant ovarian cancer (PROC). According to Genmab, clinical data suggests Rina-S could potentially treat the entire PROC population regardless of FRα expression levels.
"Based on the data from the ongoing clinical trials, Genmab intends to broaden the development plans for Rina-S within ovarian cancer and other FRα-expressing solid tumors," the company stated in its announcement.
Implications for Ongoing Collaborations
Despite the legal conflict, Genmab emphasized that its existing collaboration with AbbVie related to epcoritamab, another therapeutic in development, will continue unaffected. "We remain fully committed to the epcoritamab broad clinical development program and our commercialization efforts," the company stated.
Genmab has indicated it does not plan to provide additional information about the litigation until a decision is rendered or the case concludes.
Industry Context
This lawsuit highlights the increasingly competitive landscape in antibody-drug conjugate development, a rapidly growing segment of oncology therapeutics. ADCs combine the targeting precision of monoclonal antibodies with potent cytotoxic payloads, allowing for more targeted delivery of cancer-killing agents to tumor cells while potentially reducing systemic toxicity.
The technical aspects of linker chemistry represent a critical component of ADC design, affecting drug stability, pharmacokinetics, and therapeutic index. Innovations in this area can provide significant competitive advantages in a market projected to reach over $15 billion by 2030.
About the Companies
Genmab, headquartered in Copenhagen, Denmark, is an international biotechnology company focused on developing innovative antibody therapeutics. Founded in 1999, the company has established itself as a leader in antibody technology platforms including bispecific T-cell engagers, ADCs, and immune checkpoint modulators.
AbbVie, formed in 2013 as a spin-off from Abbott Laboratories, is a global pharmaceutical company with a strong oncology portfolio. Its ADC product Elahere (mirvetuximab soravtansine) is currently approved for FRα-positive, platinum-resistant ovarian cancer.
The case underscores the high stakes and intense competition in the development of next-generation cancer therapeutics, where proprietary technology platforms and intellectual property can significantly impact market position and patient access to novel treatments.
