Multinational phase 2 trial of pelabresib plus ruxolitinib for Janus kinase inhibitor-naïve myelofibrosis

Pelabresib is an investigational, selective oral bromodomain and extraterminal domain inhibitor. Arm 3 of the multinational phase 2 MANIFEST trial evaluated the combination of pelabresib and ruxolitinib for Janus kinase inhibitor-naïve myelfibrosis. Spleen volume reduction of at least 35% at 24 weeks (primary end point) was observed in 68% of patients, and total symptom score reduction of at least 50% at 24 weeks was seen in 56%. In substantial proportions of patients hemoglobin levels and fibrosis improved. At least 24 weeks of therapy was completed by 95% of patients.