The U.S. Food and Drug Administration approved axatilimab-csfr (Niktimvo), a colony stimulating factor-1 receptor-blocking antibody for treating chronic graft-vs-host disease in adult and pediatric patients weighing at least 40 kg (approximately 88 lbs) who have failed at least two prior lines of systemic therapy.
The efficacy of axatilimab-csfr was evaluated in the randomized, open-label, multicenter AGAVE-201 trial (ClinicalTrials.gov identifier NCT04710576) investigating three dosages in patients with recurrent or refractory graft-vs-host disease (GVHD) requiring additional treatment after receiving at least two lines of systemic therapy, according to the FDA.
The major efficacy outcome measure was overall response rate (ORR) through Cycle 7 Day 1, which included complete or partial response according to the 2014 National Institutes of Health Consensus Development Project on Response Criteria. The recommended axatilimab-csfr dose for patients weighing at least 40 kg is 0.3 mg/kg, up to a maximum dose of 35 mg, administered as an intravenous infusion over 30 minutes every 2 weeks until disease progression or unacceptable toxicity.
In the 79 patients treated with the recommended dosage, the ORR was 75% (95% confidence interval [CI] = 64–84). The median time to first response was 1.5 months (range = 0.9–5.1), and the median duration of response, calculated from first response to progression, death, or new systemic therapies for chronic GVHD, was 1.9 months (95% CI = 1.6–3.5). Among patients who achieved response, 60% (95% CI = 43–74) did not experience death or initiate new systemic therapy for at least 12 months since response.
The most common (≥ 15%) adverse reactions, including laboratory abnormalities, were increased aspartate aminotransferase, infection (pathogen unspecified), increased alanine aminotransferase, decreased phosphate, decreased hemoglobin, viral infection, increased gamma glutamyl transferase, musculoskeletal pain, increased lipase, fatigue, increased amylase, increased calcium, increased creatine phosphokinase, increased alkaline phosphatase (ALP), nausea, headache, diarrhea, cough, bacterial infection, pyrexia, and dyspnea.