Phase I study of panobinostat and 5-azacitidine in Japanese patients with myelodysplastic syndrome or chronic myelomonocytic leukemia.

The current therapy for high-risk myelodysplastic syndrome (MDS) involves repeated cycles of the DNA demethylating agent 5-azacitidine (5-Aza), but combination treatments have been proposed to improve patient outcomes. We performed a phase Ib study to investigate the safety and tolerability of 5-Aza (75 mg/m2) combined with the histone deacetylase inhibitor panobinostat (PAN) in adult Japanese patients with MDS or chronic myelomonocytic leukemia (CMML). Eleven patients were enrolled; five received 20 mg PAN + 5-Aza and six received 30 mg PAN + 5-Aza. All patients in the 20 mg PAN cohort had MDS, while two in the 30 mg PAN cohort had MDS and three had CMML. All patients experienced ≥1 adverse event (AE) related to the study treatment, and five discontinued the study treatment because of AEs. One patient in each group exhibited dose-limiting toxicities: lung infection (PAN 20 mg + 5-Aza) and cellulitis (PAN 30 mg + 5-Aza). PAN exposure increased with ascending doses, and combination therapy did not affect PAN plasma trough concentrations. In summary, 20 or 30 mg PAN combined with 5-Aza was safe and tolerable in adult Japanese patients with CMML or MDS. Study registration ClinicalTrials.gov Identifier: NCT01613976.