Interferon No Better Than Hydroxyurea and Associated with Worse Side Effects in Polycythemia Vera and Essential Thrombocythemia
The use of interferon as initial therapy in MPN is associated with worsening side effects the longer it is used for treatment. These results were recently presented at the 2016 annual meeting of the American Society of Hematology.
Myeloproliferative neoplasms (MPNs) are a related group of blood cancers. In these disorders, the bone marrow cells that produce blood cells develop and function abnormally. The three main types of MPNs are polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). In addition to developing on its own, PMF may also develop as a result of ET or PV.
Myeloproliferative neoplasms are most common in older adults. Out of every 100,000 people in the United States, an estimated 44 to 57 people have PV, and a similar number have ET. Myelofibrosis is less common, affecting 4 to 6 people per 100,000.
Quality of life issues associated with treatment are an important consideration for patients with MPNs, as some drugs can cause severe side effects without a clear benefit in outcomes compared to other treatment choices.
Researchers affiliated with the Myeloproliferative Disorders Research Consortium recently conducted a global phase III trial—referred to as the MPD-RC 112 trial—to compare initial treatment for patients with high-risk PV and ET. The interim trial results were presented at the 2016 ASH meeting.
Patients in the trial were treated with either pegylated interferon alpha-2a (PEG) or hydroxyurea (HU) and were directly compared.
- Overall, responses to treatment were similar between the two groups of patients.
- Patients experienced different degrees of disease symptoms while on therapy, as well as different side effects associated with PEG and HU.
- Side effects from PEG tended to worsen the longer patients received treatment.
Compared to HU, PEG appears to confer not improvement in response rates, but it is associated with side effects that tended to get worse with lengthening of treatment. With additional follow up it will be beneficial to determine if long-term disease control with PEG is worth the reduced quality of life associated with long-term use of PEG. While PEG may benefit selected patients, HU has the similar efficacy, with fewer side effects and is easier to administer. Perhaps more important however is that the newer JAK inhibitor drugs appear superior to HU.3
- Mascarenhas J, Prchal J, Rambaldi A, et al. Interim Analysis of the Myeloproliferative Disorders Research Consortium (MPD-RC) 112 Global Phase III Trial of Front Line Pegylated Interferon Alpha-2a Vs. Hydroxyurea in High Risk Polycythemia Vera and Essential Thrombocythemia. Proceedings from the 2016 annual meeting of the American Society of Hematology. Abstract #479.
- Mesa R, Hoffman R, Kosiorek H, et al. Impact on MPN Symptoms and Quality of Life of Front Line Pegylated Interferon Alpha-2a Vs. Hydroxyurea in High Risk Polycythemia Vera and Essential Thrombocythemia: Interim Analysis Results of Myeloproliferative Disorders Research Consortium (MPD-RC) 112 Global Phase III Trial. Proceedings from the 2016 annual meeting of the American Society of Hematology. Abstract #4271.
- Passamonti F, Griesshammer M, Palandri F, et al. Ruxolitinib Proves Superior to Best Available Therapy in Patients with Polycythemia Vera (PV) and a Nonpalpable Spleen: Results from the Phase IIIb RESPONSE-2 Study. Abstract ##S112. 21st Congress of the European Hematology Association (EHA) Copenhagen, Denmark, 2016.
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