Dr Kitko on Clinical Outcomes With Axatilimab According to Prior Lines of Therapy for Chronic GVHD

“We looked at the data in several ways. If [a patient] had been exposed to prior [lines] before receiving axatilimab, response rates still looked excellent, though they were maybe slightly lower [in those exposed to] belumosudil vs ruxolitinib before starting axatilimab. That being said, we’re looking at very small numbers, so it is hard to really make any statistical comparisons of response rates between those 2 drug groups."

Carrie L. Kitko, MD, associate professor, pediatrics, Hematology/Oncology, Ingram Professorship in Pediatric Oncology, Department of Pediatrics, medical director, Pediatric Stem Cell Transplantation Program, Vanderbilt University Medical Center, Vanderbilt Children’s Hospital, discusses the effect of treatment with ruxolitinib (Jakafi) and other immunosuppressive agents on outcomes with the novel colony-stimulating factor 1 (CSF-1R)–blocking antibody axatilimab-csfr (Niktimvo) among patients with chronic graft-vs-host-disease (GVHD).

Findings from a post hoc analysis of the phase 1 AGAVE-201 trial (NCT04710576) were presented at the 2025 Transplantation & Cellular Therapy Meetings, and showed that treatment with axatilimab produced rapid and durable overall response rates (ORRs) in patients with chronic GVHD, irrespective of the number of previous lines of therapy they received, Kitko reports.

Among all patients treated with axatilimab (n = 241), the ORRs were comparable across subgroups based on prior response, at 64.6% (95% CI, 53.3%-74.9%) for those who previously achieved a complete response (CR) or partial response (PR; n = 82), 62.1% (95% CI, 52.6%-70.9%) for those with no change in response (n = 116), and 62.5% (95% CI, 35.4%-84.8%) for those with disease progression (n = 16). ORRs also appeared to increase slightly with additional prior lines of therapy. For those with exposure to 2 prior lines of therapy (n = 35), the ORR was 51.4% (95% CI, 34.0%-68.6%); for those exposed to 3 prior lines (n = 49), it was 61.2% (95% CI, 46.2%-74.8%); for those exposed to 4 prior lines (n = 49), it was 63.3% (95% CI, 48.3%-76.6%).

For patients who received axatilimab at 0.3 mg/kg, the ORRs were 63.3% (95% CI, 43.9%-80.1%) in the prior CR/PR group (n = 30), 81.3% (95% CI, 63.6%-92.8%) in the no change group (n = 32), and 83.3% (95% CI, 35.9%-99.6%) in the disease progression group (n = 6). The ORRs at this dose were 63.6% (95% CI, 30.8%-89.1%) for those who had received 2 lines of therapy (n = 11), 53.3% (95% CI, 26.6%-78.7%) for those who had received 3 prior lines of therapy (n = 15), and 82.4% (95% CI, 56.6%-96.2%) for those who had received 4 lines of therapy (n = 17).

Patients who received rituximab in the last line of therapy (n = 68) had an ORR of 61.8% (95% CI, 49.2%-73.3%), with a median time to response (TTR) of 1.9 months (range, 0.9-5.8) and a sustained response rate of 43.0% (95% CI, 31%-55%). In those who received belumosudil in the last line of therapy (n = 34), the ORR was 50.0% (95% CI, 32.4%-67.6%), with a median TTR of 1.9 months (range, 0.9-3.9) and a sustained response rate of 26.0% (95% CI, 13%-44%).

These findings suggest that axatilimab may provide a meaningful clinical benefit across different prior treatment histories in chronic GVHD, including in patients previously treated with ruxolitinib or other immunosuppressive agents. However, Kitko cautions against making statistical comparisons between responses obtained according to whether ruxolitinib or belumosudil were previously received due to the small sample size.