Sanofi Ends Nurix's STAT6 Program, and the Milestones Go With It

Sanofi has terminated Nurix's licensed STAT6 degrader program — a drug designed to destroy a target protein — ending its Phase 1 trial and its potential milestones.

Nurix Therapeutics, Inc. (NASDAQ: NRIX) is a Brisbane, California biotech. It develops targeted protein degradation medicines. Those are drugs designed to destroy disease-linked proteins instead of blocking them. STAT6 is a transcription factor, a protein that switches genes on.

Sanofi ended the program

Nurix announced on Nov. 3 that Sanofi had notified it of the decision. Sanofi discontinued the Phase 1 first-in-human trial of SAR448272. It also terminated the SAR448272 program itself. SAR448272 is an oral STAT6 degrader licensed from Nurix.

Nurix filed the same decision with the Securities and Exchange Commission that day. Its Form 8-K recorded the termination as an other-events item. The filing and the release describe the same decision, in the same terms. No second version of the event exists in either document.

The milestones that will not arrive

As a result, Nurix does not anticipate any future milestone payments for SAR448272. It also does not anticipate royalties on any future sales of the drug. Those payments covered development, regulatory and commercial steps. Each step had to happen before any money arrived.

Nurix's October update sized what is now gone. It said Nurix remained eligible for about $455 million in future milestones on the STAT6 program. Nurix had already earned about $139 million under the Sanofi collaboration. A $10 million milestone came when the first patient was dosed in the trial.

The $455 million was potential money, not booked revenue. It depended on development, approval and sales steps that will now not happen. Losing it removes future upside for Nurix. It does not remove cash the company already holds.

What survives inside the Sanofi deal

Nurix remains eligible for milestones and royalties on its other licensed Sanofi programs. Sanofi may develop those programs further into clinical candidates. That choice sits at Sanofi's discretion, on Nurix's own description. The collaboration itself has not been terminated.

The deal dates to 2019, when Nurix used its DEL-AI discovery platform for Sanofi. In 2025, Sanofi exercised a license extension option for two programs. One targeted STAT6, and the other target remains undisclosed. Both target transcription factors for autoimmune and inflammatory diseases.

For both programs, Nurix retains an option to co-develop in the United States. It also retains an option to co-promote there. That option follows a demonstration of clinical proof of concept. The terminated program no longer reaches that test.

The position Nurix pointed to

Chief Executive Arthur T. Sands called the news disappointing. He said Nurix remains in a strong position. He cited a substantial cash runway and three clinical-stage programs. Those programs span its wholly owned and partnered portfolio.

Nurix said the announcement does not change its recently issued cash runway guidance. Cash, cash equivalents and marketable securities were $1.1 billion as of August 31, 2026. The company expects that balance to fund operations into the second half of 2029. That expectation is the company's own guidance, not a reported result.

Bexobrutideg, its lead degrader partnered with Roche, is in a Phase 3 trial. That trial enrolls patients with chronic lymphocytic leukemia. Its wholly owned NX-1607 is advancing in Phase 1b cohorts. Those cohorts cover lung, colon and prostate cancers and melanoma. An IRAK4 degrader with Gilead is advancing through Phase 1 trials for rheumatoid arthritis.

Shares fell sharply after hours

Shares fell 31.10% in after-hours trading to $17.79 as of 7:56 p.m. ET on Tuesday, according to Nasdaq quote data. The official regular close was $25.82, up 0.47%. That figure is an after-hours snapshot, not a close.

Nurix had closed Monday at $25.70, the prior close. The regular session ended before the 4:01 p.m. ET announcement. The after-hours move was the market's first verdict on the termination. It priced the lost milestones, not the cash balance.

What remains unknown

What remains unknown includes why Sanofi ended the program. Neither Nurix's release nor its filing gives a scientific, safety or commercial reason. Reuters reported that Sanofi did not immediately respond to a request for comment. No explanation from Sanofi was available when the decision was announced.

Whether Sanofi advances the other licensed programs is also unknown. Whether the after-hours drop holds on Wednesday is likewise unknown. After-hours snapshots can fade or deepen. The official test is the next regular close.

What to watch next

What to watch is any statement from Sanofi explaining the termination. Watch whether Sanofi advances the other licensed programs into clinical candidates. Watch Nurix's next update for any change to its runway guidance. None of those tests has a date yet.

Watch the next regular close against the after-hours snapshot. Watch bexobrutideg's Phase 3 progress with Roche. That partnered program now carries more of Nurix's story. Watch NX-1607's Phase 1b cohorts for the same reason.