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# Partial Clinical Hold on Sanofi MS Drug Trial
- URL: https://www.fdaweb.com/partial-clinical-hold-on-sanofi-ms-drug-trial/
- Published: 2022-06-30T12:00:00.000Z
- Updated: 2026-09-14T17:50:48.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5152208

FDA has placed a partial clinical hold on a Sanofi Phase 3 trial of tolebrutinib for use in treating multiple sclerosis and myasthenia gravis. The partial clinical hold pauses new enrollments in the trial, the company [says](https://www.sanofi.com/en/media-room/press-releases/2022/2022-06-30-05-30-00-2471767?ref=fdaweb.com). The Sanofi statement says the agency's action was based on a limited number of cases of drug-induced liver injury that have been identified with tolebrutinib exposure in Phase 3 studies.

“The majority of the impacted patients were determined to have concurrent complications known historically to predispose to drug-induced liver injury,” Sanofi says. “Importantly, the elevations of laboratory values used for monitoring liver injury were reversible after drug discontinuation for all cases. Following earlier dialog with FDA about these cases, study protocols were revised in May to update the monitoring frequency, and enrollment criteria were revised to exclude preexisting risk factors for hepatic dysfunction.”