A resurgence in biotech flotations around the JP Morgan conference has seen the CAR-T player Poseida file to raise $115 on Nasdaq. Those poring over the IPO document will notice the company’s claim to have a “proprietary” rimiducid-activated off-switch as a means of ablating its CAR-T cells in the event of a safety problem; the very same technology lies behind Bellicum, and served as its unique selling point when it floated back in 2014. “We’re aware of what [Poseida] is doing,” Rick Fair, Bellicum’s chief executive, told Vantage. “They’ve made some claims about differentiation from our construct, and that will get sorted out either with them or legally.” The IP behind this technology seems unclear, and groups like Cellectis and Autolus have claimed to have similar approaches, while the identical switch is used by academics, a non-commercial setting that Bellicum has sometimes permitted. Either way, Bellicum’s focus has shifted towards triggers to activate T cells, as seen in its lead CAR-T asset, BPX-601. Whether an off-switch is even needed is unclear as CAR-T toxicities like cytokine release have proved manageable with Actemra. Poseida declined to be interviewed during JP Morgan.