Pelabresib (CPI-0610; PELA) is an investigational oral small-molecule drug designed to inhibit bromodomain and extra-terminal domain (BET)-mediated gene transcription involved in myelofibrosis pathogenesis.

[1][2] A phase one study of pelabresib in patients with relapsed/refractory lymphomas found pelabresib is capable of BET target gene suppression in an exposure-dependent manner with an acceptable safety profile leading to the recommended phase II dose of the 125 mg tablet once daily.

[3][4] In MANIFEST-2, a phase three, randomized, blinded study compares pelabresib and ruxolitinib with placebo and ruxolitinib in myelofibrosis patients that have not been previously treated with Janus kinase inhibitors (JAKi).

[5][6] NCT02158858, a phase one/two open-label, sequential dose escalation study of pelabresib in patients with previously treated acute leukemia, myelodysplastic syndrome, myelodysplastic/myeloproliferative neoplasms, and myelofibrosis is ongoing.

[7] A third study, NCT06401356, is ongoing to provide continued access to treatment with pelabresib for patients who previously received pelabresib in a parent study and to continue collecting safety and efficacy information, such as a patient's leukemia-free survival and overall survival status during and after the treatment is ended.