ASCO: JAK2 inhibitor ruxolitinib has promising efficacy in CMML patients

Chronic myelomonocytic leukemia (CMML) is a rare type of myelodysplastic, myeloproliferative neoplasm characterized by increased numbers of peripheral monocytes and less than 20 percent blasts. CMML has few treatment options and patients only survive on average for 12 to 24 months. Preclinical studies suggest that JAK2 inhibitors may be an effective treatment option for CMML. Eric Padron, M.D., assistant member of the Malignant Hematology Program at Moffitt Cancer Center will report on the first phase 1 study of the JAK2 inhibitor ruxolitinib in CMML patients at the 2015 American Society of Clinical Oncology Annual Meeting in Chicago.

The Moffitt team and their collaborators performed a dose-escalation study of ruxolitinib in 19 CMLL patients. Ruxolitinib displayed minimal toxicity, with no dose-limiting toxicities observed and only one grade 3 or higher adverse event.

Efficacy data suggest that ruxolitinib is a promising treatment option for CMML patients. Out of fifteen patients who were evaluable for response, 3 displayed hematologic improvement and 1 patient had a partial response. Nine of the patients entered the trial with an enlarged spleen, and 5 of these patients had a greater than 50 percent reduction in their spleen size.

Ruxolitinib may be particularly beneficial for patients who have B symptoms, as 10 out of 11 patients with disease related symptoms had a clinically meaningful or complete resolution of their symptoms.

The researchers determined a phase 2 recommended dose of 20 mg twice a day, and a phase 2 study of ruxolitinib in CMML patients is planned.

The data from the phase 1 trial of ruxolitinib in CMML patients will be presented during a poster discussion session on Sunday, May 31, 11:30 a.m.-12:45 p.m. in room E354b and during the poster session from 8-11:30 a.m. in S Hall A.