Sanofi terminated development of Nurix Therapeutics’ Phase I immunology candidate SAR448272 (NX-3911), triggering a sharp market reaction. The decision ends work on the STAT6 degrader despite the broader multi-year collaboration continuing, according to Nurix disclosures. Investors focused on the impact to the collaboration’s clinical-stage trajectory; the program had been in first-in-human study in Europe with planned expansion that previously triggered payments. Nurix said its cash runway would not be affected by the SAR448272 decision. The episode highlights how even large platform deals in protein degradation can narrow quickly based on early clinical findings. It also emphasizes the financial and portfolio-rebalancing consequences of stopping a lead mechanism in a shared pipeline.