Phase 3 blood cancer vaccine trial moves toward final analysis
Galinpepimut-S study is looking for improvement in survival time
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A Phase 3 clinical trial testing the experimental cancer vaccine galinpepimut-S (GPS) in people with acute myeloid leukemia (AML), a type of blood cancer, is nearing its end, according to an update from the therapy’s developer, Sellas Life Sciences.
The Phase 3 trial, dubbed REGAL (NCT04229979), enrolled more than 100 people with AML who were in remission following at least two previous lines of therapy. Patients were randomized to receive treatment with GPS or with their doctor’s choice of available treatments. The study’s main goal is to determine whether GPS treatment leads to significant improvements in overall survival time. For AML patients at this stage of disease, median expected survival with standard care is less than a year.
REGAL is designed so that a final analysis to compare survival outcomes will be conducted once 80 of the patients in the study have died. Based on earlier expectations, Sellas believed this point would be reached before the end of 2025.
As of late December, 72 participants had died, the company said. The study is still blinded, so Sellas doesn’t have access to information on whether patients who died had received GPS or not. Sellas said it will announce when the 80th death occurs and a final analysis can be carried out.
“We appreciate the continued dedication of the patients, families, and investigators participating in the pivotal Phase 3 REGAL trial where survival times, fortunately for patients and caregivers, appear longer than expected,” Angelos Stergiou, MD, president and CEO of Sellas, said in a company press release. “While the 80th event has not yet occurred, and we remain fully blinded, every passing month may increase the probability of a successful study … Conclusive data will follow the unblinding and analyses of the study results.”
Early data suggest treatment extends life
“We remain steadfast in our commitment to advancing breakthrough therapies, such as GPS, that possess the potential to significantly improve the lives of patients with AML,” Stergiou said.
GPS is designed to trigger an immune response against a protein called WT1, which is expressed at high levels by cancer cells. The therapy aims to teach the immune system to eliminate AML cells in a manner similar to the way conventional vaccines instruct the immune system to eliminate infections. Interim data from last year suggested patients in the trial tend to live longer than is typically expected.
“The REGAL study represents a meaningful effort to evaluate GPS as a novel therapeutic approach in an AML population with significant unmet need,” said Yair Levy, MD, a member of the REGAL study’s steering committee and director of hematologic malignancies research at Texas Oncology-Baylor University Medical Center. “For patients who are unable to undergo transplant, as in the REGAL study, their treatment usually consists of a combination of hypomethylating agents and/or a BCL-2 inhibitor, with an expected median overall survival of around eight months. We hope to see an extended survival benefit, with a tolerable safety profile, as observed in previous GPS studies.”
