Researchers at Washington University School of Medicine have conducted a Phase I clinical trial showing that the investigational drug itacitinib may reduce the risk of graft-versus-host disease (GvHD) in patients undergoing half-matched (haploidentical) stem cell transplants for blood cancers like leukemia and lymphoma. This drug targets a critical pathway in the immune response, reducing the likelihood of GVHD without compromising the transplant’s effectiveness.
The study included 42 patients who received itacitinib, a JAK inhibitor, along with standard care to prevent GvHD both before and after the transplant. Particularly, none of the patients developed severe GvHD (grade 3 or 4) within 180 days—far fewer than the 10–15% typically seen with standard treatments.
Patients also exhibited a one-year overall survival rate of 80%, with 89% showing no signs of chronic GvHD. Senior author Dr. John F. DiPersio noted, “We saw no severe GvHD, and the rates of relapse were lower than expected in these high-risk patients. Low GvHD rates and low relapse resulted in the survival for the patients in this study.”
This is especially relevant as half-matched stem cell transplants—where the donor’s immune system proteins match 50% of the recipient’s—have become more common due to the difficulty of finding fully matched donors. These findings suggest that incorporating itacitinib into pre-transplant protocols could make half-matched transplants safer and more accessible.
Though the study lacked a control group and was focused on safety, the results suggest itacitinib could play a significant role in reducing GvHD. Larger studies are planned to further assess its effectiveness in preventing this life-threatening complication.
