Galinpepimut-S
An investigational treatment for Acute Myeloid Leukemia.
The same compound appears under different names depending on the context. Here is how to identify Galinpepimut-S wherever you encounter it, plus the key facts at a glance.
- Generic name
- Galinpepimut-S
- Development codes
- GPS, WT1 peptide vaccine
- Drug class
- Cancer vaccine (WT1-targeted peptide immunotherapy)
- Manufacturer
- SELLAS Life Sciences
- How it's taken
- Subcutaneous injections with GM-CSF (investigational)
An investigational vaccine given by injection to people whose AML is in a second complete remission, meant to keep the leukemia from returning. Its Phase 3 REGAL trial has finished enrolling and will be analyzed once 80 deaths have occurred; SELLAS reported 78 as of May 11, 2026 and remains blinded. It is not FDA approved.
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Where Galinpepimut-S fits
There is no approved maintenance treatment for AML in second remission; Onureg is approved only after a first remission. If REGAL is positive, galinpepimut-S would be the first immunotherapy in that setting.
How Galinpepimut-S works
WT1 (Wilms tumor 1) is a protein that most AML cells make in large amounts and normal adult cells rarely do. Galinpepimut-S is a mix of 4 WT1 peptide fragments, 2 of them modified to be more visible to the immune system, given with an adjuvant (Montanide) and the growth factor GM-CSF so that the body raises both killer and helper T cells against WT1. The idea is to use the immune system to clear the small number of leukemia cells left after chemotherapy while a person is in remission[3][1].
Mechanism: Peptide immunotherapy that trains T cells against WT1, a protein overexpressed by AML cells, to attack residual leukemia during remission
Side effects and safety
There is no FDA label. SELLAS's public updates describe the trial as ongoing and blinded and do not report safety results from REGAL; earlier Phase 2 studies of the vaccine at Memorial Sloan Kettering are summarized on ClinicalTrials.gov. Injection site reactions are the expected effect of a peptide vaccine with an adjuvant, but the REGAL safety data have not been disclosed[1].
This is not a complete list of side effects. Talk to your doctor or pharmacist about what to expect and when to seek medical attention.
Taking Galinpepimut-S
Investigational. In REGAL the vaccine is given as injections under the skin together with GM-CSF, compared against the investigator's choice of best available therapy, which can include azacitidine, venetoclax, decitabine, cytarabine or observation[1]. It is available only through the trial or SELLAS's expanded access program (NCT05593185)[2].
Availability and cost
Only available as the brand-name product.
Clinical trial results
REGAL (NCT04229979) is a randomized, open-label Phase 3 trial of galinpepimut-S against best available therapy in 127 adults with AML in a second or later complete remission (CR2 or CRp2) after salvage therapy, with overall survival as the primary endpoint. It is listed as active, not recruiting, with a primary completion date of December 2025 on its record last updated October 1, 2025[1].
The final analysis is event driven: SELLAS said on March 19, 2026 that 72 events had occurred by December 26, 2025, on May 12, 2026 that its contract research organization had counted 78 events as of May 11, 2026, and on August 11, 2026 that it would announce the 80th event, which triggers database lock, blinded review, unblinding and topline results.
No announcement of the 80th event or of results had been made as of October 19, 2026[4][3][5]. The FDA granted Rare Pediatric Disease Designation for pediatric AML on October 15, 2024[6].
Development history
Galinpepimut-S was developed at Memorial Sloan Kettering Cancer Center and licensed to SELLAS. A Phase 2 study in AML and ALL in remission ran from 2011 to 2016 (NCT01266083), and REGAL began enrolling in February 2021. SELLAS has said it is preparing a potential Biologics License Application for after the final analysis, if the result is positive[3].
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Where to access Galinpepimut-S
Investigational: available only through clinical trial enrollment
Galinpepimut-S has not been approved by the FDA and is not available by prescription. The only way for a patient to receive Galinpepimut-S today is by enrolling in an active clinical trial and meeting that trial's eligibility criteria. Decisions about trial participation should be made with the specialist who manages the patient's condition and knows their current treatment.
Primary active trial
ClinicalTrials.gov record NCT04229979
View full trial record on ClinicalTrials.gov →Trial status, site list, and eligibility are pulled from ClinicalTrials.gov. Confirm current recruitment status and nearest site directly with the study team before traveling.
Common questions about Galinpepimut-S
▸What is Galinpepimut-S?
An investigational vaccine given by injection to people whose AML is in a second complete remission, meant to keep the leukemia from returning. Its Phase 3 REGAL trial has finished enrolling and will be analyzed once 80 deaths have occurred; SELLAS reported 78 as of May 11, 2026 and remains blinded. It is not FDA approved.
▸How does Galinpepimut-S work?
WT1 (Wilms tumor 1) is a protein that most AML cells make in large amounts and normal adult cells rarely do. Galinpepimut-S is a mix of 4 WT1 peptide fragments, 2 of them modified to be more visible to the immune system, given with an adjuvant (Montanide) and the growth factor GM-CSF so that the body raises both killer and helper T cells against WT1. The idea is to use the immune system to clear the small number of leukemia cells left after chemotherapy while a person is in remission[3][1].
▸What are the side effects of Galinpepimut-S?
There is no FDA label. SELLAS's public updates describe the trial as ongoing and blinded and do not report safety results from REGAL; earlier Phase 2 studies of the vaccine at Memorial Sloan Kettering are summarized on ClinicalTrials.gov. Injection site reactions are the expected effect of a peptide vaccine with an adjuvant, but the REGAL safety data have not been disclosed[1].
▸How is Galinpepimut-S taken?
Investigational. In REGAL the vaccine is given as injections under the skin together with GM-CSF, compared against the investigator's choice of best available therapy, which can include azacitidine, venetoclax, decitabine, cytarabine or observation[1]. It is available only through the trial or SELLAS's expanded access program (NCT05593185)[2].
▸Is Galinpepimut-S FDA approved?
Galinpepimut-S is currently in phase 3 clinical trials for Acute Myeloid Leukemia. It has not yet received FDA approval.
Sources and references
Every factual claim on this page is drawn from the public sources listed below. Click any reference to open the original document.
- ClinicalTrials.gov. Galinpepimut-S Versus Investigator's Choice of Best Available Therapy for Maintenance in AML CR2/CRp2 (REGAL). https://clinicaltrials.gov/study/NCT04229979
- ClinicalTrials.gov. Expanded Access Program for Galinpepimut-S (GPS) in Patients Diagnosed With AML or MDS. https://clinicaltrials.gov/study/NCT05593185
- SELLAS Life Sciences Group · 2026-08-11. SELLAS Life Sciences Reports Second Quarter 2026 Financial Results and Provides Corporate Update. https://ir.sellaslifesciences.com/news/News-Details/2026/SELLAS-Life-Sciences-Reports-Second-Quarter-2026-Financial-Results-and-Provides-Corporate-Update/default.aspx
- SELLAS Life Sciences Group · 2026-03-19. SELLAS Life Sciences Reports Full Year 2025 Financial Results and Provides Corporate Update. https://ir.sellaslifesciences.com/news/News-Details/2026/SELLAS-Life-Sciences-Reports-Full-Year-2025-Financial-Results-and-Provides-Corporate-Update/default.aspx
- SELLAS Life Sciences Group. SELLAS Life Sciences news releases, 2026. https://ir.sellaslifesciences.com/news/
- SELLAS Life Sciences Group · 2024-10-15. SELLAS Announces U.S. FDA Rare Pediatric Disease Designation (RPDD) Granted to Galinpepimut-S (GPS) for the Treatment of Pediatric Acute Myeloid Leukemia. https://ir.sellaslifesciences.com/news/News-Details/2024/SELLAS-Announces-U.S.-FDA-Rare-Pediatric-Disease-Designation-RPDD-Granted-to-Galinpepimut-S-GPS-for-the-Treatment-of-Pediatric-Acute-Myeloid-Leukemia/default.aspx