Venetoclax is a B-cell lymphoma-2 (BCL-2) inhibitor approved for use in patients with chronic lymphocytic leukemia (CLL). Because patients who have undergone allogeneic hematopoietic stem-cell transplant (allo-HSCT) are generally disqualified from participating in clinical trials, little is known about the outcomes of targeted CLL therapy with venetoclax after allo-HSCT, including its effect, if any, on graft-versus-host disease (GVHD).
To determine the effects of targeted CLL treatment with venetoclax after allo-HSCT, researchers from several institutions in Italy performed an observational, multicenter, retrospective study. The results were presented by Francesca Perutelli, MD, Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy, in an abstract at the 11th Annual Meeting of the Society of Hematologic Oncology (SOHO), Houston, Texas.
Of the 53 institutions queried, 35 responded, yielding only 7 patients who received venetoclax after allo-HSCT. These patients received treatment between 2006-2021, and all had failed prior treatment with either chemotherapy, ibrutinib, idelalisib, or some combination of those therapies. Three of the 7 had received some degree of venetoclax therapy before transplant. Five of 7 patients also underwent non-myeloablative conditioning before transplant.
The researchers reported that venetoclax appeared safe after allo-HSCT, with no adverse events differing from standard venetoclax clinical trials. The drug did not appear to exacerbate pre-existing chronic GVHD in 4 of the 7 patients who had it, and it appeared to improve GVHD symptoms for 2 of the patients. One patient developed GVHD during treatment with venetoclax. Of the 7 patients who received treatment, 2 achieved undetectable minimal residual disease in bone marrow.
“Previous allo-HSCT did not compromise sensitivity to venetoclax, which was capable of inducing objective responses without exacerbating GVHD,” the team concluded.
Perutelli F, Boccellato E, Catania G, et al. Venetoclax Therapy in Chronic Lymphocytic Leukemia Patients Relapsed After Allogeneic Hematopoietic Stem Cell Transplantation. Abstract CLL-347. Presented at the 11th Annual Meeting of the Society of Hematologic Oncology; September 6-9, 2023; Houston, Texas.