Final results from the phase 2 COMBI II trial demonstrated high rates of remission of newly-diagnosed polycythemia vera (PV) after treatment with ruxolitinib plus pegylated-interferon-α2a (peg-IFN), according to a report published in Blood Advances.
The COMBI I trial previously demonstrated efficacy and safety of the combination of ruxolitinib with peg-IFN among patients who were refractory or intolerant to peg-IFN monotherapy and/or hydroxyurea.
“This study supports the previously described theory that combination therapy with ruxolitinib and peg-IFN may be one of the most promising treatment options in patients with myeloproliferative neoplasms,” the researchers wrote in their report.
In the investigator-initiated, single-center, phase 2 study, researchers treated 25 adult patients with newly-diagnosed PV with ruxolitinib and peg-IFN. All patients underwent pretreatment phlebotomies and patients who were high-risk, aged 60 or older, or who had a prior thrombosis also received hydroxyurea.
The primary endpoint was safety and secondary endpoints included complete remission (CR), peripheral blood count remission (PBCR), and bone marrow histologic remission (BMHR).
The median age of the patients was 70 years and 56% were male. The median number of phlebotomies from diagnosis to study entry was 3. There were 76% of patients who were considered high-risk, 20% had a prior thrombosis, and 12% had splenomegaly. The median hemoglobin was 13.8 g/dL and the median hematocrit was 0.44 IQR. The median variant allele fraction (VAF) of JAK2 V617F at baseline was 54 IQR.
Remission was achieved by 52% of patients by 12 months, with 12% of patients having achieved a CR. At 24 months, the overall remission rate was 56% and the CR rate remained at 12%.