Roxadustat versus placebo for patients with lower-risk myelodysplastic syndrome: MATTERHORN phase 3, double-blind, randomized controlled trial.

In patients with lower-risk myelodysplastic syndromes/neoplasms (MDS), response to first-line therapy is limited and transient. The MATTERHORN randomized, double-blind, phase 3 trial evaluated roxadustat versus placebo for patients with transfusion-dependent, lower-risk MDS. Eligible patients had very low-, low-, or intermediate-risk MDS with or without prior erythropoiesis-stimulating agent treatment, and a transfusion burden of 1-4 packed red blood cell (pRBC) units every 8 weeks (Q8W). Patients were randomized (3:2) to oral roxadustat (2.5 mg/kg) or placebo, both three times weekly, with best supportive care. Primary efficacy endpoint was transfusion independence (TI) for ≥56 days within 28 weeks (TI responders). MATTERHORN was terminated due to interim analysis outcomes not meeting statistical significance. In total, 272 patients were screened, and 140 patients were enrolled (82, roxadustat, and 58, placebo). At final analysis, 38/80 (47.5%) patients and 19/57 (33.3%) in the roxadustat and placebo arms, respectively, were TI responders (p = .217). A greater percentage of patients in the roxadustat arm with a transfusion burden of ≥2 pRBC units Q4W were TI responders (36.1%; 13/36) compared with the placebo arm (11.5%; 3/26; p-nominal = .047). The seven on-study deaths (4, roxadustat, and 3, placebo) were considered unrelated to treatment. Three roxadustat patients progressed to acute myeloid leukemia. Despite MATTERHORN not meeting its primary endpoint, a numerically higher TI rate was achieved with roxadustat treatment compared with placebo. Further analyses are needed to confirm the MDS patient subgroups deriving clinical benefit from this novel treatment.