Niktimvo (axatilimab-csfr) is a prescription medicine used to treat chronic graft-versus-host disease (cGVHD) in patients who failed at least two prior treatments. cGVHD is a long-term condition that occurs after a transplant when donor cells attack the body's tissues. Niktimvo works by blocking colony-stimulating factor-1 (CSF-1) receptors on certain immune cells, helping to reduce inflammation and prevent further tissue damage.