Posoleucel Efficacious for Stem Cell Transplant Recipients

TUESDAY, Jan. 17, 2023 (HealthDay News) -- For recipients of allogeneic hematopoietic cell transplantation (allo-HCT) with refractory viral infections/disease, the T-cell therapy posoleucel is well tolerated and effective, according to a study published online Jan. 11 in Clinical Cancer Research.

Thomas Pfeiffer, Ph.D., from the Washington University School of Medicine in St. Louis, and colleagues conducted an open-label phase 2 trial to examine the feasibility and safety of posoleucel in 58 adult and pediatric allo-HCT recipients infected with one or more of adenovirus, BK virus (BKV), cytomegalovirus, Epstein-Barr virus, human herpes virus-6, and JC virus. Infections were unresponsive to, or patients could not tolerate, standard antiviral therapies.

The researchers found that posoleucel was well tolerated, with no evidence of cytokine release syndrome or other infusion-related toxicities. During the trial, two and one patient (3.4 and 1.7 percent) developed grade 2 and grade 3 graft-versus-host disease, respectively. At six weeks after the first posoleucel infusion, the overall response rate was 95 percent, with a 97 percent reduction in median plasma viral load. Ten (83 percent) of the 12 patients with two or more target viral infections identified at study entry had a clinical response for all evaluable viruses. Seventy-four percent of the 23 patients treated for refractory BKV-associated hemorrhagic cystitis had symptom resolution and macroscopic hematuria by six weeks after infusion.

"Results of our trial suggest that posoleucel is a safe and effective therapy for the treatment of severe viral infections following allogeneic HCT," the authors write. "Its use might aid in alleviating the morbidity and mortality associated with post-HCT viral infections and helps avoid the nephrotoxic and myelosuppressive side effects associated with the use of conventional antiviral medications."

Several authors disclosed financial ties to biopharmaceutical companies, including AlloVir, which manufactures posoleucel and contributed funding to the study.

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