Galinpepimut-S Immunotherapy Has Preliminary Efficacy in Acute Myeloid Leukemia

Among patients with acute myeloid leukemia (AML) in remission following second-line salvage therapy, the immunotherapeutic agent galinpepimut-S (GPS) demonstrated preliminary signals of efficacy and specific T-Cell immune responses in the pivotal phase 3 REGAL trial, according to a press release from SELLAS Life Sciences Group, Inc.

After a median follow-up of 13.5 months, fewer than half of patients enrolled in the REGAL trial were confirmed deceased. These results indicated a median survival of over 13.5 months compared with the historical median survival from a similar phase 2 study of only six months for conventional therapy.

Based on these findings, the Independent Data Monitoring Committee (IDMC) has recommended the continuation of the clinical trial without any modifications. Notably, the IDMC went on to share that the agent exceeded predetermined futility criteria.

“Based on all available data, we believe that GPS could become a transformative treatment option for AML, offering hope to patients with limited choices, especially those with relapsed or refractory disease. We are optimistic about the IDMC’s recommendation to continue the study without modifications and diligently preparing for the Biologics License Application (BLA),” said Dr. Angelos Stergiou, President and Chief Executive Officer of SELLAS, in the news release. “Importantly, the REGAL trial provides a clear and straightforward path toward seeking regulatory approval for patients with AML in their second complete remission.”

Furthermore, 80% of randomly selected patients enrolled on the REGAL who received GPS exhibited T-cell immune response, outperforming the findings from the previous phase 2 study.

No new safety concerns were noted throughout the duration of the trial.

These efficacy results are consistent with the findings of previous GPS trials. As such, in the phase 2 study of patients with AML in second complete remission, the median overall survival (OS) for GPS-treated patients was 21 months, compared with 5.4 months for patients receiving standard-of-care therapy, with a 64% GPS-specific immune response.

Allogeneic stem cell transplantation (allo-SCT) holds promise for curing some patients with relapsed or refractory AML who can achieve a second or more remissions with salvage therapy. However, several obstacles hinder transplantation, and not all patients with relapsed or refractory AML are eligible to proceed to allo-SCT.

Currently, no drug has been approved for the maintenance of remission in patients with AML following second-line salvage therapy, which further emphasizes the importance of this development, according to the news release.

GPS is a type of cancer vaccine that uses pieces of a protein called WT1, which is often found in cancer cells, according to the SELLAS website. Furthermore, the vaccine is designed to help the body's immune system create a strong innate immune response and fight cancer cells that have this protein, according to the National Cancer Institute’s website.

The REGAL phase 3 study is an open-label registrational clinical trial evaluating the efficacy of GPS in patients with AML who have achieved complete remission following second-line salvage therapy.

A final analysis to confirm the efficacy of GPS will be conducted once 80 events, or deaths, have occurred, which is expected to take place this year, the trial anticipates, according to the release.

The primary end goal of the study was OS.

“The interim results represent a major step forward in the treatment of AML, offering hope for patients in remission,” Dr. Yair Levy, Director of Hematologic Malignancies Research at Texas Oncology Baylor University Medical Center, in Dallas, said in the news release. “I am very hopeful that we will see a new standard of care in treating AML patients based on the outcomes we have observed in previous GPS trials.”

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