The myeloproliferative disorders consist of polycythemia vera, chronic myelogenous leukemia, agnogenic myeloid metaplasia, and essential thrombocythemia. All these disorders are thought to result from a hematopoietic stem cell lesion.
Interferon alfa is effective in suppressing bone marrow function in chronic myeloproliferative disorders, but this treatment requires multiple weekly injections. Pegylated interferon, on the other hand, can be given weekly. Several groups reported on the results of phase 2 trials of pegylated interferon alfa 2b in essential thrombocytosis and polycythemia vera with generally concordant results.Satisfactory platelet count reduction was achieved with 3 to 6 months of therapy in approximately 70% of patients, but the drug had to be discontinued in 15% to 52% of them because of side effects. In the one study in which marrow histology was examined, progression of myelofibrosis was not inhibited by pegylated interferon. The number of studies and quality of evidence meets Caremark criteria for approval. The therapy is not investigational and it is medically necessary.
Gugliotta L, Bulgarelli S, Tienghi A, et al. Bone marrow biopsy and aspirate evaluation in 90 patients with essential thrombocythemia treated with peg interferon alpha-2b. Preliminary results. Blood. 2004;104:11. Abstract 1523.
Samuelsson J, Hasselbalch H, Bruserud O, et al. A phase II trial of pegylated interferon alpha-2b in polycythemia vera and essential thrombocythemia: clinical responses, effects on PRV-1 expression and impact on quality of life. Blood. 2004;104:11. Abstract 1518.
Langer C, Lengfelder E, Thiele J, et al. Treatment with pegylated interferon alpha (Pegintron) for high-risk essential thrombocythemia: results of a phase II study. Blood. 2004;104:11. Abstract 1522.
Verstovsek S, Lawhorn K, Giles F, et al. PEG-intron for myeloproliferative diseases: an update on ongoing phase II study. Blood. 2004;104:11. Abstract 1517.
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