Dr. Garcia on Efficacy of Navitoclax in Ruxolitinib-Resistant Myelofibrosis

Jacqueline S. Garcia, MD, instructor in medicine, Department of Medical Oncology, Harvard Medical School, and physician, Dana-Farber Cancer Institute, discusses results from a phase II trial examining the addition of the BCL-2/BCL-XL inhibitor navitoclax to ruxolitinib (Jakafi) in patients with primary or secondary myelofibrosis with acquired resistance to ruxolitinib.

Results from the study were impressive, according to Garcia. Investigators were able to demonstrate the regimen’s tolerability in 34 patients treated on the study. Evidence of thrombocytopenia, fatigue, and diarrhea were reported, says Garcia. Cytopenias occurred with the regimen, but leukocytosis improved. Generally, hemoglobin remained stable across the board for several weeks, even up to week 72, adds Garcia.

Platelet levels dropped between weeks 6 and 8 of treatment; however, the mean platelet level was 90,000, which is acceptable, according to Garcia. Most of the toxicities were low grade with only 1 incidence of grade 4 thrombocytopenia reported; that event was found to be reversible with a temporary dose hold.

Investigators are looking forward to see more data from the trial to confirm the safety of the regimen and further evaluate its efficacy, says Garcia. Ongoing efforts are dedicated to further categorizing these patients as well as to study navitoclax in combination as a monotherapy for patients with advanced myelofibrosis, concludes Garcia.