Johnson & Johnson agreed to buy Firefly Bio for $1 billion in cash, gaining a degrader antibody conjugate (DAC) platform. The transaction expands J&J’s options for targeted protein degradation approaches that combine antibody specificity with pharmacology designed to degrade disease-relevant proteins. Firefly Bio’s technology centers on DACs—antibody-conjugated degraders intended to drive intracellular target elimination rather than receptor blockade alone. J&J’s move signals continued interest in next-generation antibody modalities that can act deeper in cells. The deal is structured to provide Firefly Bio shareholders with an immediate premium via cash consideration, while positioning J&J to accelerate development of DAC programs across multiple therapeutic areas using Firefly’s platform capabilities.