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# Serina Files Response on Parkinson’s Drug Clinical Hold
- URL: https://www.fdaweb.com/serina-files-response-on-parkinsons-drug-clinical-hold/
- Published: 2025-12-11T12:00:00.000Z
- Updated: 2026-09-14T15:28:54.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5160373

Serina Therapeutics says it has filed a complete response to an FDA clinical hold issued 11/25 on SER-252, the company’s lead investigational therapy for advanced Parkinson’s disease. The hold was placed after the agency requested additional information about a commonly used formulation excipient. The agency did not raise concerns about apomorphine, the therapy’s active drug substance, its mechanism of action, the enFuse delivery device, or the 505(b)(2) development strategy the company has discussed with the agency, according to the company.

Serina says its response included data supporting the use of trehalose as a subcutaneous excipient at the intended dose, comparative information to approved products containing trehalose, and additional nonclinical analyses. The company also provided a revised protocol enabling initiation of the study’s single-ascending-dose (SAD) phase.

The company now anticipates starting the SAD portion of the SER-252-1b trial in the first quarter of 2026, pending FDA’s decision. “

SER-252 is a POZ-apomorphine formulation designed to deliver continuous dopaminergic stimulation, which has been shown to reduce levodopa-related motor complications. Serina says its POZ platform, based on a poly (2-oxazoline) polymer, is intended to enable more precise drug-loading and controlled release for subcutaneous delivery.