Regeneron Pharmaceuticals has broadened its cancer immunotherapy focus by partnering with gene therapy specialist Bluebird Bio. On August 6, the companies announced a collaboration to discover and commercialize cancer immunotherapies, with a deal that includes six initial targets. Regeneron is also buying $100 million in Bluebird stock, which will be credited against its initial 50% research funding obligation.

Bluebird develops individualized cancer treatments using chimeric antigen receptor T cells (CAR-Ts). Its technology takes human immune cells—typically T cells derived from the patient—and uses a customized lentiviral vector to modify the T cells so that they can recognize tumor-specific proteins expressed by cancer cells and kill them. The cells are then returned to the patient to serve as therapeutic agents that specifically target and kill cancer cells.

Regeneron brings to the table platform technologies for the discovery and characterization of fully human antibodies and T cell receptors directed against tumor-specific proteins and peptides. The goal of combining the technologies is to expand the types of tumors that modified T cells can target by enabling them to reach both extracellular and intracellular tumor antigens. The deal sees the partners sharing research and development costs equally for drug candidates up to the time of filing to begin human clinical studies. At that point, Regeneron may opt in to codevelop and cocommercialize a drug, sharing costs and profits 50:50.

The new arrangement comes as Regeneron awaits a US Food and Drug Administration approval decision on its first immunotherapy, the anti-PD-1 checkpoint inhibitor antibody cemiplimab, for treating advanced cutaneous squamous cell carcinoma. Known primarily for its immunology medicines and treatment for macular degeneration, Regeneron has been building a pipeline in cancer immunotherapy for some time. It has two other checkpoint inhibitors in the clinic, against lymphocyte-activation gene 3 and cytotoxic T-lymphocyte associated protein 4 (a target often combined with a PD-1). A bispecific antibody targeting CD20 and CD3 could enter a pivotal study for approval in 2019, with other bispecifics in or about to enter the clinic.