A Study of Axatilimab at 3 Different Doses in Participants With Chronic Graft Versus Host Disease (cGVHD)

This is a Phase 2 study to evaluate the efficacy, safety, and tolerability of axatilimab at 3 different dose levels in participants with recurrent or refractory active chronic graft versus host disease (cGVHD) who have received at least 2 prior lines of systemic therapy.

Inclusion Criteria: 1. Participants must be 2 years of age or older, at the time of signing the informed consent. 2. Participants who are allogeneic hematopoietic stem cell transplantation (HSCT) recipients with active cGVHD requiring systemic immune suppression. Active cGVHD is defined as the presence of signs and symptoms of cGVHD per 2014 NIH Consensus Development Project on Criteria for Clinical trials in cGVHD. 3. Participants with refractory or recurrent active cGVHD despite at least 2 lines of systemic therapy. * Refractory disease defined as meeting any of the following criteria: * The development of 1 or more new sites of disease while being treated for cGVHD. * Progression of existing sites of disease despite at least 1 month of standard or investigation therapy for cGVHD. * Participants who have not achieved a response within 3 months on their prior therapy for cGVHD and for whom the treating physician believes a new systemic therapy is required. * Recurrent cGVHD is active, symptomatic disease (after an initial response to prior therapy) as defined, based on the NIH 2014 consensus criteria, by organ-specific or global assessment or for which the physician believes that a new line of systemic therapy is required. 4. Participants may have persistent, active acute and cGVHD manifestations (overlap syndrome), as defined by 2014 NIH Consensus Development Project on Criteria for Clinical trials in cGVHD. 5. Karnofsky Performance Scale of ≥60 (if aged 16 years or older); Lansky Performance Score of ≥60 (if aged \