Sanofi terminated development of Nurix Therapeutics’ Phase I immunology candidate SAR448272 (NX-3911), a STAT6 degrader, ending a program tied to the companies’ nearly seven-year protein-degradation collaboration. Nurix said its cash runway and remaining clinical programs are not expected to change, but the market reacted sharply, with the stock falling 38% after the news. The collaboration, valued at up to $2.5 billion, began in January 2020 and originally included milestone and target-expansion payments. Sanofi’s pullout focused specifically on the SAR448272 asset, while claiming the broader collaboration continues. Clinically, the candidate had been in first-in-human testing in Europe, with recruitment planned for Germany and expansion into additional countries. Strategically, the termination underscores how early-stage clinical readouts can rapidly reshape platform economics in protein degradation portfolios.