Ruxolitinib Combo Therapy Reduces Symptom Burden in Patients With PV, MF

Results from a study of patients with polycythemia vera (PV) and myelofibrosis (MF) showed that ruxolitinib therapy plus low-dose pegylated interferon-α2 (PEG-IFNα2) improved cell counts and reduced symptom burden with acceptable toxicity (Haematologica. 2019 Dec 26. Epub ahead of print).

Anders Lindholm Sørensen, MD, Department of Hematology, Zealand University Hospital, Roskilde, Denmark, and colleagues conducted the 2-year clinical trial to evaluate the use of combination ruxolitinib and low-dose PEG-IFNα2 in 32 patients with PV and 18 with primary- or secondary MF. Of these patients, 46 had previous intolerance of or were refractory to PEG-IFNα2.

The primary end point of the study was efficacy, determined via hematologic parameters, quality of life measurements, and JAK2 V617F allele burden.

“We used the 2013 ELN and IWG-MRT response criteria, including response in symptoms, splenomegaly, peripheral blood counts, and bone marrow,” Dr Sørensen et al explained.

Overall, 10 (31%) patients with PV achieved remission, including 3 (9%) who achieved complete remission, and 8 (44%) patients with MF achieved remission, including 5 (28%) who achieved complete remission.

Patients with PV and MF had a cumulative incidence of peripheral blood count remission of 0.85 and 0.75, respectively. In addition, MPN-SAF total symptom score went from 22 (95% CI, 16-29) at baseline to 15 (95% CI, 10-22) after 2 years.

Findings also demonstrated a decrease in median JAK2 V617F allele burden from 47% (95% CI, 33-61%) to 12% (95% CI, 6-22%), with 41% of patients achieving a molecular response. For patients with PV and MF, the drop-out rate was 6% and 32%, respectively.

Notably, 31 (86%) of 36 patients who had a previous intolerance to PEG-IFNα2 completed the study, 24 (67%) of whom received PEG-IFNα2 throughout the trial.

“In conclusion, combination treatment improved cell counts, reduced bone marrow cellularity and fibrosis, decreased JAK2 V617F burden, and reduced symptom burden with acceptable toxicity in several patients with [PV or MF],” Dr Sørensen and colleagues concluded.—Hina Porcelli