How to get reasonable efficacy in cancer without toxicity – problematic especially in older patients – is a dilemma made ever more poignant by the advent of CAR T therapies and bispecific antibodies, which have been showing overall response rates of about 70%, but with side effects that can severely limit their use. Invariant natural killer T cells may provide an answer, and New York-based Mink Therapeutics Inc. aims to find out.