Johnson & Johnson agreed to buy Firefly Bio for $1 billion in cash, targeting a new therapeutic modality in degraders delivered via antibody conjugates. The acquisition is designed to broaden J&J’s oncology platform with “degrader-antibody conjugates,” which combine an antibody targeting mechanism with payloads that drive protein degradation rather than classical cytotoxic release. Firefly’s approach is highlighted in the company’s preclinical focus on KRAS-driven tumors, with J&J emphasizing the potential to overcome limitations seen in some antibody-drug conjugates related to payload release. The company said the purchase expands its pipeline technology and strengthens its ability to develop therapies across solid tumors. The move follows a period of accelerated interest in degraders and ADC-adjacent formats among large pharma, and it signals J&J’s intent to build defensible IP and platform capability rather than relying only on individual assets.