ROCK2 Inhibition With Belumosudil Yields Promising Results for cGVHD

Belumosudil, an oral ROCK2 inhibitor, produces high overall response rates (ORR) and demonstrates quality-of-life improvements in patients with chronic graft-vs-host disease (cGVHD), according to a phase IIa study reported in the Journal of Clinical Oncology (online April 20, 2021; doi:10.1200/JCO.20.02754).

“The rho-associated coiled-coil–containing protein kinase-2 (ROCK2) signaling pathway regulates the Th17/regulatory T cells balance and controls profibrotic pathways. Selective ROCK2 inhibition with belumosudil may offer a novel approach to the management of cGVHD,” said Madan Jagasia, MD, MS, Vanderbilt-Ingram Cancer Center, Nashville, Tennessee, and colleagues.

To evaluate the safety and efficacy of belumosudil, Dr Jagasia conducted an open-label, dose-finding study which utilized data between September 2016 and March 2018 from 7 centers in the United States, and included 54 patients with cGVHD who had received 1 to 3 prior lines of therapy.

Patients received belumosudil in 3 ways: 17 patients at 200mg once daily (cohort 1), 16 at 200 mg twice daily (cohort 2), and 21 at 400mg twice daily (cohort 3), each in 28-day cycles until disease progression or unacceptable toxicity. All patients were receiving corticosteroid (CS) treatment. Overall, 78% of patients had severe cGVHD, 50% had 4 or more organs involved, 73% had cGVHD refractory to their last line of therapy (LOT), and 50% had received 3 or more prior LOTs.

The primary end point was overall response rate (ORR) with progression defined per the 2014 NIH cGVHD Consensus Criteria.

With an overall median follow-up of 29 months, the ORR (95% CI) for cohorts 1, 2, and 3 was 65% (38% to 86%), 69% (41% to 89%), and 62% (38% to 82%), respectively. Responses were clinically meaningful, with a median duration of response (DOR) of 35 weeks, and 38 weeks for patients who had received 2 or more prior systemic LOTs. Responses were also associated with quality-of-life improvements, CS dose reductions and limited toxicity. CS treatment was discontinued in 19% of patients.

The failure-free survival (FFS) rate (95% CI) was 76% (62% to 85%), 47% (33% to 60%), and 33% (21% to 46%), at 6, 12, and 24 months, respectively. Reasons for failure included starting a new systemic therapy (n=27), relapse of the disease (n=7), and death (n=2). The 2-year overall survival (OS) rate was 82% (69% to 90%).

Overall, belumosudil was well-tolerated, with low rates of cytopenia. There were no underlying adverse events and no apparent increased risk of infection, including cytomegalovirus (CMV) infection and reactivation.

“Belumosudil treatment resulted in a high ORR and overall survival rate and demonstrated quality-of-life improvements, CS dose reductions, and limited toxicity. Data from the study indicated that belumosudil may prove to be an effective therapy for patients with treatment-refractory cGVHD,” Dr Jagasia concluded.—Emily Bader