Results from a new clinical trial have shown that the targeted therapy drug ibrutinib, a BTK inhibitor, can effectively treat graft-versus-host disease (GVHD), a common complication from allogeneic stem cell transplants. The study findings were reported at the American Society of Hematology’s 2016 annual meeting.

In the phase II study involving 42 patients, approximately two-thirds of patients saw improvements in their GVHD symptoms, and of those, 21% eliminated their symptoms completely.

Before the symptoms resolved, the patients had been experiencing them for a median of 13.7 months. The symptoms were being managed with steroids, but many patients were able to reduce their steroid dose or stop using steroids altogether.

Many patients reported having less severe symptoms after using ibrutinib, as measured by a standardized scoring system. Levels of blood-based markers associated with GVHD were also reduced, including those associated with inflammation and connective tissue scarring.

Serious side effects, including high fevers and pneumonia, were reported in 22 patients (52%), and two fatal events (multilobular pneumonia and bronchopulmonary aspergillosis) were reported. But for most of the patients, the side effects were manageable, and the researchers said that the benefits may outweigh the risks for many patients with chronic GVHD.

The researchers concluded that the study’s response rates support further study of ibrutinib for frontline treatment of GVHD.