Cellectis aims for safer CAR T construct

In a paper published online in Scientific Reports, researchers from Cellectis S.A. (Euronext:ALCLS; NASDAQ:CLLS) reported a new chimeric antigen receptor T cell construct designed to decrease the on-target, off-tumor activity responsible for much of the cells' toxicity. The new construct incorporates an oxygen-sensitive domain that restricts CAR T cell activity to hypoxic environments, such as the tumor microenvironment.

To avoid side effects of highly potent CAR T cell therapies, most cell therapy developers including Cellectis are incorporating safety switches into the construct design, such as small molecule- or antibody-controlled domains that either activate or inactivate the cells. In the new paper, the researchers described a regulation mechanism that doesn't require external molecules to control cell activation, but rather keeps the cells inactive until they enter the tumor microenvironment...