Sanofi Initiates Phase 1 Trial of Oral STAT6 Degrader SAR448272, Triggering $10M Milestone Payment to Nurix
Key Insights
Sanofi has dosed the first patient in a Phase 1 first-in-human trial of SAR448272 (search), an oral small-molecule degrader targeting STAT6 for type 2 inflammatory diseases.
Nurix receives a $10 million milestone payment, bringing total proceeds from the 2019 Sanofi collaboration to approximately $139 million, with up to $453 million in remaining STAT6 milestones.
SAR448272 (search) eliminates STAT6 protein rather than merely blocking its activity, offering a differentiated oral approach compared to injectable biologics like dupilumab.
Sanofi has initiated a Phase 1 first-in-human clinical trial of SAR448272 (search) (also known as NX-3911), an oral small-molecule degrader targeting STAT6, triggering a $10 million milestone payment to its collaboration partner Nurix Therapeutics. The milestone, announced by Nurix on August 4, 2026, brings the total payments received under the companies' 2019 collaboration agreement to approximately $139 million, with Nurix remaining eligible for roughly $453 million in future development, regulatory, and commercial milestones tied to the STAT6 program alone.
The trial marks the first clinical evaluation of a STAT6-targeted protein degrader, a mechanistic approach that differs fundamentally from the injectable biologics currently dominating the type 2 inflammatory disease market.
Mechanistic Rationale: Degradation Over Inhibition
STAT6 functions as a key transcription factor within the interleukin-4 (IL-4) and interleukin-13 (IL-13) signaling pathways, sitting at the convergence point through which both cytokines drive pathology in atopic dermatitis (search), asthma (search), and other type 2 inflammatory conditions. Rather than blocking upstream cytokine signals—as dupilumab does by inhibiting the IL-4 receptor alpha subunit via subcutaneous injection—SAR448272 (search) is designed to eliminate STAT6 protein entirely through targeted protein degradation.
As an oral agent, SAR448272 (search) offers a differentiated route of administration. The degrader approach may also address residual function that simple inhibition leaves intact in certain tissues, though whether this translates into clinical advantage remains to be demonstrated.
Trial Design and Development Structure
Sanofi holds sole responsibility for conducting the Phase 1 trial, a structure that shields Nurix's cash runway from the costs of early clinical development. The study is expected to evaluate safety, pharmacokinetics, and early signals of target engagement, including STAT6 protein levels in accessible compartments such as peripheral blood mononuclear cells.
Nurix retains a co-development and co-promotion option in the United States that can be exercised following demonstration of clinical proof of concept. This arrangement allows the company to review efficacy data before committing capital to a larger share of the program. Under the terms, Nurix would share profits and losses equally in the United States if it exercises the option.
Platform Validation and Pipeline Context
SAR448272 (search) was discovered using Nurix's DEL-AI drug discovery platform, which integrates artificial intelligence with DNA-encoded library technology to identify novel agents that harness E3 ligases for targeted protein degradation. The platform is also active across partnerships with Gilead and Pfizer, meaning the STAT6 clinical data will carry implications beyond this single asset.
"Advancing SAR448272 (search) into the clinic marks an important milestone for the STAT6 program and further validates the productivity of our DEL-AI drug discovery platform in generating differentiated degrader medicines for immunology," said Gwenn M. Hansen, Ph.D., chief scientific officer of Nurix.
Arthur T. Sands, M.D., Ph.D., president and chief executive officer of Nurix, added: "The advancement of SAR448272 (search) into Phase 1 builds on the strong momentum across our partnered immunology portfolio and reflects the continued execution of our strategy to create significant value through both our wholly owned and partnered degrader programs."
Financial and Strategic Implications
The 2019 collaboration began with a $55 million upfront payment from Sanofi, followed by an additional $22 million to expand the scope. In June 2025, Sanofi exercised its exclusive license extension option for two programs—STAT6 and an undisclosed transcription factor target—triggering two $15 million license extension payments. With the latest $10 million Phase 1 initiation milestone, cumulative payments stand at approximately $139 million.
The near-term clinical signal to watch will be the Phase 1 dose-escalation readout on STAT6 degradation depth. Robust target engagement at tolerated doses would validate the oral degrader approach in immunology and strengthen the case for Nurix to exercise its U.S. co-promotion option—a decision that would signal substantially greater conviction in the program than any milestone payment alone.