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# CDER Head Targets Surrogate Endpoints, Lupus Drug
- URL: https://www.fdaweb.com/cder-head-targets-surrogate-endpoints-lupus-drug/
- Published: 2025-09-30T12:00:00.000Z
- Updated: 2026-09-14T15:23:01.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5159958

CDER director **George Tidmarsh** has questioned the use of surrogate endpoints and has publicly attacked Aurinia Pharmaceuticals’ Lupkynis (voclosporin), which was approved in 2021 for treating lupus nephritis. In an unprecedented and now-deleted LinkedIn post, Tidmarsh claimed that voclosporin has “significant toxicity” and has not been shown to have a clinical benefit for patients. A subsequent, and now-deleted, post by Tidmarsh noted that his earlier post reflected his own views and did not represent FDA’s opinions.

“CDER will be evaluating surrogate endpoints used for FDA approval,” Tidmarsh said in the post. “While there is no doubt that the use of such endpoints has benefited patients by bringing valuable treatments to patients sooner, there have been notable failures in confirmatory trials, such as those for exon skipping therapies in DMD \[Duchenne muscular dystrophy\]. And for some diseases such as lupus nephritis, companies have not run trials to demonstrate a benefit on hard clinical endpoints like progression to end-stage renal disease. So we have approved drugs with significant toxicity like voclosporin that has not been shown to provide a direct clinical benefit for patients. We will be taking a close look at the use of surrogate endpoints to see where we can further accelerate promising drugs faster while requiring companies to perform the trials necessary to confirm actual clinical benefit.”

It’s unclear what motivated Tidmarsh to single-out Lupkynis or question surrogate endpoints. *Stat* [has speculated](https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.statnews.com/2025/09/29/fda-george-tidmarsh-linkedin-aurinia/&ved=2ahUKEwiNxN7rjYGQAxU-mokEHfyoLj0QFnoECB0QAQ&usg=AOvVaw0fnEo6ZmhE9t6IlALoX8EJ) it might have something to do with Tidmarsh’s previous affiliation with Aurinia’s board chair **Kevin Tang**, whom Tidmarsh worked with previously at La Jolla Pharmaceuticals. Tidmarsh left La Jolla in 2019, at which time a La Jolla press release had Tang noting that Tidmarsh resigned to “pursue other interests,” according to *Stat*.

FDA commissioner **Marty Makary** brought Tidmarsh on board in July to fill the CDER head vacancy left by former Center director **Patrizia Cavazzoni**, who departed the agency in the early days of the Trump administration. At the time, Makary said his “appointment to lead CDER brings exceptional scientific, regulatory, and operational expertise to the agency.”

Tidmarsh has over 30 years of experience in the biotechnology industry, including the clinical development of six FDA-approved drugs, according to his [bio](https://med.stanford.edu/profiles/george-tidmarsh?ref=fdaweb.com). He previously served as the founder and chief executive officer of Horizon Pharma, where he led the development of Duexis, which was approved for treating rheumatoid arthritis. In 2022, Horizon was sold to Amgen for $28B, his bio says. He also founded Threshold Pharmaceuticals, Inc. and held senior positions at Coulter Pharmaceutical, Inc. (acquired by GlaxoSmithKline) and SEQUUS Pharmaceuticals, Inc. (acquired by Johnson & Johnson). While at Coulter and SEQUUS, Tidmarsh led the clinical development of Bexxar and Doxil, two FDA-approved anti-cancer agents.