Pegylated Interferon Alfa 2a Therapy in Patients with Myeloproliferative Disorders: A Review of Clinical Effectiveness and Cost-Effectiveness

Key Message

Two primary studies regarding the clinical effectiveness of pegylated interferon alfa 2a therapy in patients with myeloproliferative disorders were included in this report. No economic evaluations regarding the cost-effectiveness of pegylated interferon alfa 2a therapy in this population were identified. Overall, the body of evidence was limited in quantity and was moderate in quality.

The identified literature revealed varied conclusions regarding the clinical effectiveness of pegylated interferon alfa 2a therapy in patients with myeloproliferative disorders depending on the specific population, comparator treatment, and assessed outcome. Specifically, for patients with chronic-phase chronic myeloid leukemia included in the randomized controlled trial, there were no significant differences in complete hematologic or cytogenetic response amongst four treatment groups (i.e., imatinib plus pegylated interferon alfa 2a, imatinib plus cytarabine, imatinib 400 mg, imatinib 600 mg). Imatinib plus pegylated interferon alfa 2a resulted in significantly greater rates of major and superior molecular response, but also significantly higher rates of grade 3-4 neutropenia and thrombocytopenia, compared to imatinib 400 mg monotherapy. Information on survival outcomes was not reported in this randomized controlled trial.

In patients with polycythemia vera and myelofibrosis included in the non-randomized study, no significant differences in partial or complete response were detected amongst the three treatment groups (i.e., pegylated interferon alfa 2a, ruxolitinib, hydroxyurea ± anagrelide). However, in patients with essential thrombocythemia included in the non-randomized study, pegylated interferon alfa 2a resulted in significantly greater rates of complete response compared to ruxolitinib and hydroxyurea ± anagrelide. In the total cohort of patients with polycythemia vera, myelofibrosis, and essential thrombocythemia, pegylated interferon alfa 2a and hydroxyurea ± anagrelide resulted in significantly less improvement in quality of life compared to ruxolitinib. In the total cohort of patients, grade 1-2 adverse events were seen in 62%, 44%, and 20%, and grade 3-4 adverse events were seen in 7%, 0%, and 9% of participants receiving pegylated interferon alfa 2a, hydroxyurea ± anagrelide, and ruxolitinib, respectively (statistical analysis not reported).

Statistical tests in the randomized controlled trial and non-randomized study were mainly conducted for differences across all treatment groups, with additional post hoc tests to determine between-group differences for only select outcomes. Furthermore, the small sample size (N = 125) in the non-randomized study should also be taken into consideration when interpreting these results.5 Additionally, since the sample populations consisted of patients living in France and Hong Kong, these findings may not be generalizable to the Canadian setting.