Serina Therapeutics Submits Complete Response to FDA Clinical Hold Letter for SER-252 Program
Rhea-AI Summary
Serina Therapeutics (NYSE: SER) submitted a complete response to the FDA clinical hold for its lead program SER-252 on December 9, 2025. The filing addresses FDA questions about the commonly used excipient trehalose with a detailed data package and includes a revised protocol to start the single ascending dose (SAD) phase.
The FDA issued a formal full clinical hold on November 25, 2025; dosing cannot begin until the hold is lifted. Serina continues global site start-up and regulatory activities, and now expects first-patient-in (FPI) in Q1 2026, subject to timely FDA resolution and customary approvals.
Positive
- Complete response submission dated Dec 9, 2025
- Data package supporting trehalose as subcutaneous excipient
- Revised protocol to initiate the SAD phase
- Ongoing global site start-up with planned Q1 2026 FPI
Negative
- FDA issued a full clinical hold on the IND on Nov 25, 2025
- Dosing delayed until clinical hold is formally lifted
Key Figures
Market Reality Check
Peers on Argus
SER slipped 0.3% while close biotech peers were mixed: VTVT up 5.77%, JUNS flat, PYPD, RLMD, and MAIA down modestly. No consistent sector-wide move is evident.
Historical Context
| Date | Event | Sentiment | Move | Catalyst |
|---|---|---|---|---|
| Nov 13 | Earnings and update | Negative | -2.5% | Q3 loss, going-concern warning, and disclosure of FDA clinical hold timing. |
| Nov 03 | Clinical hold news | Negative | -6.4% | FDA placed IND for SER-252 on clinical hold over excipient data. |
| Oct 08 | Communications initiative | Positive | +4.3% | Launch of enhanced communications platform linked to SER-252-1b trial plans. |
| Oct 06 | Funding tranche draw | Positive | -0.9% | Drew first $5M tranche and highlighted IND submission and trial start goals. |
| Sep 09 | Financing agreement | Positive | +3.5% | Announced up to $20M convertible note financing for SER-252 trial. |
Recent SER-252 and financing updates often saw price move in the same direction as the news tone, with only one notable divergence on a funding/IND milestone update.
Over the last six months, Serina’s trajectory has centered on financing and progressing SER-252 for advanced Parkinson’s disease. On Sep 9 and Oct 6, the company secured and drew on up to $20M in convertible note financing tied to clinical milestones. Multiple releases in October detailed the planned registrational Phase 1b SER-252-1b design. On Nov 3, the FDA placed the IND on clinical hold, then the Nov 13 earnings and 10-Q flagged liquidity pressure and going-concern risk. Today’s complete response to the clinical hold fits this ongoing regulatory narrative.
Market Pulse Summary
This announcement shows Serina has formally answered the FDA’s clinical hold letter for SER-252, providing data on trehalose and a revised single ascending dose protocol, with first-patient-in now targeted for Q1 2026. Historically, the program has been central to the company’s financing and regulatory updates, while recent filings flagged liquidity and going-concern risk. Investors may watch for the FDA’s decision on lifting the hold and progress on the global Phase 1b registrational study.
Key Terms
investigational new drug regulatory
phase 1b medical
single ascending dose medical
AI-generated analysis. Not financial advice.
– Company addresses FDA requests regarding formulation excipient
– Global site start-up activities continue, with first-patient-in for registrational Phase 1b study targeted for Q1 2026, subject to FDA feedback
HUNTSVILLE, Dec. 10, 2025 (GLOBE NEWSWIRE) -- Serina Therapeutics, Inc. (“Serina” or the "Company") (NYSE American: SER), a clinical-stage biotechnology company advancing its lead Investigational New Drug ("IND") candidate, SER-252, for advanced Parkinson's disease, enabled by its proprietary POZ PlatformTM drug optimization technology, today announced that it has submitted a complete response to the U.S. Food and Drug Administration’s (“FDA”) clinical hold letter for SER-252, the Company’s lead program for advanced Parkinson’s disease.
As previously disclosed, the FDA placed the Company’s Investigational New Drug (“IND”) application for SER-252 on clinical hold pending additional information related to a commonly used formulation excipient. On November 25, 2025, the FDA issued a formal full clinical hold letter specifying the information required to permit initiation of the planned Phase 1b registrational study, SER-252-1b.
The issues identified by the FDA do not relate to the apomorphine active drug substance, its mechanism of action, the use of the enFuse device (Enable Injections) or the broader 505(b)(2) NDA development pathway previously discussed with the Agency.
Serina’s complete response, submitted on December 9, 2025, includes:
- A detailed data package supporting the proposed use of trehalose as a subcutaneous excipient at the intended dose, including comparative information to approved products containing trehalose and additional nonclinical analyses; and
- A revised protocol to initiate the single ascending dose (SAD) phase. Initiation of the SAD phase of the SER-252-1b trial is anticipated to begin in Q1 2026.
“Our priority has been to respond thoroughly and constructively to the FDA’s requests,” said Steve Ledger, Chief Executive Officer of Serina Therapeutics. “We believe our submission directly addresses the FDA’s questions on trehalose, and we appreciate the Agency’s continued engagement as we work toward initiating the registrational SER-252-1b trial.”
While dosing cannot begin until the clinical hold is lifted, Serina continues site start-up and regulatory activities in Australia and other regions as part of the global registrational program. In Australia, early interactions with investigators and the Parkinson’s community have helped build strong support for the trial design and its potential to address unmet needs in advanced disease. The Company now expects first-patient-in (“FPI”) in Q1 2026, subject to timely resolution of the clinical hold and customary regulatory and ethics approvals.
About Serina Therapeutics
Serina is a clinical-stage biotechnology company developing a pipeline of wholly owned drug product candidates to treat neurological diseases and other indications. Serina’s POZ PlatformTM provides the potential to improve the integrated efficacy and safety profile of multiple modalities including small molecules, RNA-based therapeutics and antibody-based drug conjugates (ADCs). Serina is headquartered in Huntsville, Alabama on the campus of the HudsonAlpha Institute of Biotechnology.
About the POZ PlatformTM
Serina’s proprietary POZ technology is based on a synthetic, water soluble, low viscosity polymer called poly (2-oxazoline). Serina’s POZ technology is engineered to provide greater control in drug loading and more precision in the rate of release of attached drugs delivered via subcutaneous injection. The therapeutic agents in Serina’s product candidates are typically well-understood and marketed drugs that are effective but are limited by pharmacokinetic profiles that can include toxicity, side effects and short half-life. Serina believes that by using POZ technology, drugs with narrow therapeutic windows can be designed to maintain more desirable and stable levels in the blood.
Serina’s POZ platform delivery technology has potential for use across a broad range of payloads and indications. Serina intends to advance additional applications of the POZ platform via out-licensing, co-development, or other partnership arrangements, including the non-exclusive license agreement with Pfizer, Inc. to use Serina’s POZ polymer technology for use in lipid nanoparticle drug (LNP) delivery formulations.
About SER-252 (POZ-apomorphine)
SER 252 is an investigational apomorphine therapy developed with Serina’s POZ platform and designed to provide continuous dopaminergic stimulation (CDS). CDS has been shown to reduce the severity of levodopa-related motor complications (dyskinesia) in Parkinson’s disease. Preclinical studies support the potential of SER 252 to provide CDS without skin reactions.
Cautionary Statement Regarding Forward-Looking Statement
References in this Report to “Serina,” “the Company,” “we” or “us” refer to Serina Therapeutics, Inc. This release contains forward-looking statements within the meaning of federal securities laws. All statements that are not historical fact, including statements about the Company’s response to the FDA’s clinical hold letter, Serina’s planned clinical programs, including timing for first-patient-in and resolution of the clinical hold and customary regulatory and ethics approvals, the potential of Serina’s POZ polymer technology, are forward-looking statements that involve substantial risks and uncertainties that could cause actual results to differ materially from those expressed or implied by such statements. These statements are based on management’s current expectations, plans, beliefs or forecasts for the future, and are subject to uncertainty and changes in circumstances. Undue reliance should not be placed on these forward-looking statements which speak only as of the date they are made, and the facts and assumptions underlying these statements may change.
Actual results may differ materially from those projected in such statements due to a variety of important factors including, among other things, the timing and extent of the FDA's clinical-hold letter and of Serina's response, the uncertainties inherent in research and development, including the ability to meet anticipated clinical endpoints, commencement and/or completion dates for clinical trials, regulatory submission dates, regulatory approval dates and/or launch dates, as well as the possibility of unfavorable new clinical data and further analyses of existing clinical data; Serina’s ability to continue as a going concern; the risk that clinical trial data are subject to differing interpretations and assessments by regulatory authorities; whether regulatory authorities will be satisfied with the design of and results from our clinical studies; whether and when any applications may be filed for any drug or vaccine candidates in any jurisdictions; whether and when regulatory authorities may approve any potential applications that may be filed for any drug or vaccine candidates in any jurisdictions, which will depend on a myriad of factors, including making a determination as to whether the product’s benefits outweigh its known risks and determination of the product’s efficacy and, if approved, whether any such drug or vaccine candidates will be commercially successful; decisions by regulatory authorities impacting labeling, manufacturing processes, safety and/or other matters that could affect the availability or commercial potential of any drug or vaccine candidates; and competitive developments. These risks as well as other risks are more fully discussed in the company’s Annual Report on Form 10-K for the year ended December 31, 2024, and the company’s other periodic reports and documents filed from time to time with the SEC. The information contained in this release is as of the date hereof, and Serina assumes no obligation to update forward-looking statements contained in this release as the result of new information or future events or developments.
For inquiries, please contact:
Stefan Riley
sriley@serinatherapeutics.com
(256) 327-9630
FAQ
What did Serina (NYSE: SER) submit to the FDA for SER-252 on December 9, 2025?
Why was the SER-252 IND on clinical hold by the FDA on November 25, 2025?
When does Serina expect first-patient-in for the SER-252 registrational Phase 1b study?
Does the FDA hold relate to the apomorphine active drug or enFuse device for SER-252?
Can Serina begin dosing SER-252 immediately after the December 9 submission?
