Checkpoint drugs fail most patients in the end, so a different attack is welcome. Invikafusp alfa tries one. It grabs a subset of T cells by their receptor chain and hands them a growth signal at the same time. In the phase 1/2 START-001 trial, led by Ryan Sullivan at Massachusetts General, the drug was mostly well tolerated. The main side effects were flu-like and manageable. Among 18 patients whose cancers had already stopped responding to immunotherapy, two in three had their disease controlled for a time. Earlier data across 52 patients showed a 61% disease-control rate. These are small, early numbers, not proof the drug extends lives. The trial is still enrolling. What makes it worth watching is the mechanism, which is new, and the target group, patients who have run out of other options. I would hold the excitement until a larger trial reports, but the logic is sound.
Source: Nature Medicine, 23 October 2026
