Johnson & Johnson Opts Out of Genmab's CD38 Antibody Program, Prompting Discontinuation

Johnson & Johnson (J&J) has decided not to exercise its option to license Genmab's HexaBody-CD38 monoclonal antibody, leading the Danish biotech company to discontinue the program entirely. This development marks a significant setback in the companies' collaboration to develop a successor to their multiple myeloma blockbuster, Darzalex.

Partnership Dissolution and Program Discontinuation

The partnership, initiated in 2019, gave J&J the option to license HexaBody-CD38 after a proof-of-concept study for $150 million, plus potential milestones and royalties. The antibody was designed using Genmab's proprietary technology aimed at enhancing the cancer-killing power of therapeutics.

Genmab cited a "thorough evaluation of the data, the market landscape and Genmab's rigorous portfolio prioritization" as reasons for discontinuing the program following J&J's decision. Jan van de Winkel, Ph.D., CEO of Genmab, expressed disappointment but emphasized the clinical potential of the HexaBody platform for future applications.

Clinical Trial Results and Competitive Landscape

The phase 2 expansion trial compared HexaBody-CD38 to subcutaneous daratumumab in patients with anti-CD38 antibody-naïve relapsed or refractory multiple myeloma. Results showed:

• Objective response rate (ORR): 55% for HexaBody-CD38 vs. 52% for daratumumab
• Complete response rate: 7% for HexaBody-CD38 vs. 2% for daratumumab

These results, while promising, were not sufficient to convince J&J to move forward with the program. The competitive landscape includes Sanofi's Sarclisa (isatuximab-irfc), a CD38-directed cytolytic antibody approved by the FDA in 2020 for both relapsed/refractory and newly treated multiple myeloma.

Market Reaction and Future Outlook

Following the announcement, Genmab's stock price dropped more than 8% from its market open price of $23.93 per share, settling at $21.98 as of 4 p.m. ET on March 10. Analysts at William Blair described the opt-out as "unfortunate but largely expected," suggesting that this development may allow investors to focus on other potential blockbusters in Genmab's pipeline, including Epkinly, Rina-S, and acasunlimab.

Despite this setback, Genmab maintains its 2025 financial guidance and continues to advance other promising candidates in its pipeline. The company recently acquired ProfoundBio for $1.8 billion, gaining rights to rinatabart sesutecan (Rina-S), a potential challenger to AbbVie's Elahere. Both Rina-S and acasunlimab, a PD-L1x4-1BB bispecific antibody, are currently undergoing phase 3 testing.