Astellas winds down Agensys, turning its back on antibody-drug conjugate research

Ten years after taking over Agensys in a $537 million deal, Japan's Astellas has decided to pull the plug on the Santa Monica-based operation.

The Japanese drugmaker said the decision reflected a shift in its priorities in cancer research, and in particular a reduced focus on antibody-drug conjugates (ADCs), which combine the targeting of monoclonal antibodies with a cell-killing payload.

Astellas paid $387 million upfront for Agensys in 2007, with another $150 million in the offing from milestone payments, buying into the company's expertise in both naked antibodies and ADCs.

The pharma group's head of drug discovery research, Wataru Uchida, Ph.D., said that Agensys has contributed multiple compounds to its pipeline, along with antibody-related technology, but added that "the field of research has evolved and led to a new frontier of treatment options."

For now, it's not clear how many jobs will go with the wind-down of Agensys, which is due to complete by the first quarter of 2018.

At Astellas' latest R&D update, the company reiterated its ambition to develop a leadership position in oncology that was kicked off by the acquisition of Agensys and bolstered with the licensing of prostate cancer therapy enzalutamide in 2009 and purchases of OSI Pharma and Ganymed in 2010 and 2016. Uchida said during that meeting that while targeted antibodies and ADCs meet Astellas' short- and medium-term goals, the company's long-term objective is to develop a portfolio of immuno-oncology therapeutics that address tumors unresponsive to the current PD-1/PD-L1 inhibitor therapies, helped by recent deals with Potenza and MD Anderson.

According to Astellas' latest pipeline update, Agensys' contribution is headed by enfortumab vedotin (ASG-22ME), an ADC targeting nectin-4 co-developed with Seattle Genetics that is in phase 2 trials in the U.S. for bladder cancer and phase 1 in Japan, and an ENPP3-targeting ADC called AGS-16C3F for renal cell carcinoma in phase 2.

The California biotech was also responsible for three phase 1 programs: tubulin polymerization inhibitors AGS67E for lymphoid cancers and ASG-15ME for bladder cancer, and AGS62P1 for acute myeloid leukemia. Another drug stemming from the Agensys deal, anti-prostate stem cell antigen candidate AGS-1C4D4, was discontinued in 2012 after reaching phase 2 development.

"Astellas will continue certain clinical trials and collaborations on ADC programs that have been in progress at Agensys, including its collaboration with Seattle Genetics," said the Japanese company.