Merck & Co. is paying $700 million upfront to challenge Amgen in a blood cancer market. The deal will give Merck global rights to Curon Biopharmaceutical’s CD3xCD19 bispecific, positioning the Big Pharma as a rival to Amgen and AstraZeneca in oncology and Cullinan Therapeutics in autoimmune disease.
Engagement of CD3 and CD19 is the mechanism that birthed the bispecific antibody industry. Amgen’s pioneering T-cell engager Blincyto, which won FDA approval in 2014, hits the two targets to treat acute lymphoblastic leukemia. Yet, while Blincyto has a huge head start, companies have identified weaknesses that they could exploit—and recent studies suggest there is an untapped autoimmune opportunity.
Merck is entering the fray by handing Curon the upfront fee and agreeing to pay up to $600 million in milestones tied to development and regulatory approval. In return, the drugmaker has bagged rights to the phase 1/2 candidate CN201.
Curon, a Chinese biotech, presented data from two clinical trials of CN201 earlier this year. The readouts provided early evidence of the efficacy of the bispecific antibody in non-Hodgkin lymphoma (NHL) and acute lymphoblastic leukemia (ALL). Curon reported complete responses in patients who had progressed on multiple other therapies.
Curon has designed the bispecific to reduce cytokine release syndrome (CRS) without compromising efficacy. In the NHL and ALL trials, the biotech saw CRS in 7% and 31% of patients, respectively. Most of the cases happened after the first dose. One patient in the ALL trial had a grade 3 reaction but the rest of the CRS cases were milder.
Merck plans to keep studying CN201 in B-cell malignancies. AstraZeneca, which acquired its CD3xCD19 bispecific AZD0486 for $100 million upfront in 2022, is also in the clinic. A phase 2 trial of AZD0486 in NHL is scheduled to start this year. AstraZeneca is already recruiting patients in early-phase ALL and NHL studies.
Autoimmune diseases are on Merck’s roadmap for CN201. Interest in targeting CD19 has intensified in recent years as researchers have published data on a CAR-T candidate in lupus. Another investigator tested Blincyto in six patients with multidrug-resistant rheumatoid arthritis. Talking at a Goldman Sachs event in June, Amgen’s chief scientific officer Jay Bradner called the responses “very dramatic.”
Cullinan made autoimmune diseases the exclusive focus of its CD3xCD19 bispecific earlier this year and is preparing to file to study the candidate in systemic lupus erythematosus. Rheumatoid arthritis is next on Cullinan’s hit list. The biotech looks set to face competition from Merck, which plans to investigate the potential of CN201 to provide a “novel, scalable option for the treatment of autoimmune diseases.”