Johnson & Johnson moved into KRAS-targeted cancer therapy with a $1 billion upfront acquisition of Firefly Bio. J&J said it is buying the startup’s Firelink degrader antibody conjugate (DAC) platform, which couples targeting antibodies to catalytic protein degraders to drive degradation of proteins, including targets considered “undruggable.” Firefly’s early pipeline is focused on KRAS-driven tumors, with preclinical work cited by the company showing tumor-volume reductions after single administrations at low doses. Firefly was incubated by Versant Ventures and previously raised a $94 million Series A. The acquisition underscores big pharma’s search for new formats beyond classic antibody-drug conjugates as competition intensifies in targeted protein therapies. J&J said Firelink’s linker technology is intended to limit free payload exposure to healthy cells while improving functional delivery to target-bearing tumor cells.