T-cell Therapy Prevents Multiple Virus Infections after Allo-HSCT

New long-term data on posoleucel, AlloVir’s multi-virus specific T-cell therapy, has shown its ability to prevent clinically significant infections in patients receiving allogeneic hematopoietic cell transplant (allo-HCT). These data, from a phase 2 study (NCT053050400), were presented at the 49th annual meeting of the European Society for Blood and Marrow Transplantation, April 23-26, in Paris, France.

“The data presented today provide further evidence supporting the potential benefits of using posoleucel to prevent viral infection in high-risk allo-HCT patients. The non-relapse mortality rate in patients receiving posoleucel was 0% through week 52 which compares favorably with published non-relapse mortality rates among allo-HCT patients ranging from 9 percent to over 15 percent," Diana Brainard, MD, chief executive officer, AlloVir, said in a statement. "Our global, registrational Phase 3 clinical trial further exploring the potential of posoleucel for multi-virus prevention is well underway and we anticipate data from this registrational study in 2024. If successful, an option that prevents viral infection, such as posoleucel, could transform the care of allo-HCT patients."

Posoleucel is an allogeneic T-celltherapy being investigated for the prevention of clinically significant infections from 6 viruses: adenovirus, BK virus, cytomegalovirus, Epstein-Barr virus, human herpesvirus-6 and JC virus. The study is evaluating the efficacy and safety of posoleucel for both the prophylaxis of patients at high risk for viral reactivation and the preemptive treatment of patients with viral reactivation who have not yet developed clinically significant infections or disease.

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The prevention study included patients that received up to 7 biweekly infusions and were tested for viremia by polymerase chain reaction against all 6 viruses weekly over 14 weeks and were then followed through week 26. The study primarily evaluated the number of new onset clinically significant infections or end-organ disease through week 14.

The new data, as of a 52-week follow-up visit, 5 participants out of 26 had died due to relapse or progression of underlying disease. No deaths were due to infection or deemed related to treatment, for a 0% non-relapse mortality. Previously reported data from the 14-week endpoint showed low rates of clinically significant viral infections and diseases, as opposed to expected high rates of viral reactivation in this high-risk patient population. The phase 3 portion of the trial is continuing to enroll patients in the US, Europe, and Asia, with data readouts expected in 2024.

"The majority of allo-HCT recipients reactivate 1 or more of posoleucel's 6 target viruses post allo-HCT, which can lead to clinically significant infections, prolonged morbidity, hospitalization and premature death," primary investigator Sanjeet Singh Dadwal, MD, chief, Division of Infectious Diseases, and Professor of Medicine, City of Hope, added to the statement. "This long-term 0% non-relapse mortality result builds upon the positive data through week 26 post-HCT, which was reported at the end of last year. These long-term follow-up data suggest that posoleucel could significantlyimpact patient outcomes. When available, I look forward to seeing the larger data set from the ongoing Phase 3 program."

REFERENCE

AlloVirannounces positive results including long-term mortality data in phase 2 posoleucel multi-virus prevention study in oral presentation at EBMT 2023. News release. AlloVir. April 26, 2023. https://ir.allovir.com/news-releases/news-release-details/allovir-announces-positive-results-including-long-term-mortality