Examining Pelabresib for Patients With Myelofibrosis

Joseph M. Scandura, MD, PhD, Weill Cornell Medicine, discusses next steps for research of pelabresib (CPI-0610) for use in patients with myeloproliferative neoplasms.

Pelabresib is an oral, small molecule inhibitor of BET, which has the potential to downregulate the expression of genes that reside within the pathogenic pathways that underlie MPN progression.

One study evaluating pelabresib is the phase 3 MANIFEST-2 trial (NCT04603495). In this multicenter, double-blind, placebo-controlled trial, investigators are examining the safety and efficacy of pelabresib plus ruxolitinib (Jakafi) vs ruxolitinib alone in patients with JAK inhibitor-naïve myelofibrosis.

Patients aged 18 years and older with primary, post-polycythemia vera, or post-essential thrombocytopenia myelofibrosis, who had advanced disease requiring therapy, splenomegaly by computed tomography or magnetic resonance imaging, and were symptomatic were eligible for enrollment. Patients must also have had a prognostic risk-factor score of intermediate-1 or higher per the Dynamic International Prognostic Scoring System.

In the study, patients were randomly assigned in a 1:1 ratio to receive ruxolitinib in addition to oral pelabresib or matched placebo daily for 14 days, which was followed by 7 days off treatment. The starting dose of pelabresib was 125 mg daily. Then, ruxolitinib was given to patients twice a day in doses of 10 mg or 15 mg. Dose increases for both were allowed per protocol criteria.

Transcription:

0:10 | The first one is that we need to wait for the data to mature. My personal bias is, all of these biomarkers are invaluable until we know outcomes such as survival or time to treatment failure or event-free survival. Until we know that, we are just kind of stuck in this circular loop of what should be, what we hope will be, what our intuitive beliefs are, but we do not really know what any of these things mean until we have those outcomes. That just takes time.

0:46 | The nice thing is there are a number of phase 3 studies, randomized trials, collaborative studies. MANIFEST-2 is a randomized phase 3 study, and that will allow us to address and follow up on some of these findings, and hopefully get to those answers about whether or not these changes that we're observing in the short-term are predicting these long-term beneficial outcomes. It just takes time for that data to mature

REFERENCE

Phase 3 study of pelabresib (CPI-0610) in myelofibrosis (MF) (MANIFEST-2) (MANIFEST-2). ClinicalTrials.gov. Updated April 6, 2023. Accessed July 6, 2023. https://clinicaltrials.gov/ct2/show/NCT04603495