Role of interferon alpha‐2a in the treatment of polycythemia vera

Abstract

We studied the effects of recombinant interferon alpha-2a (IFN-alpha) in 36 patients with polycythemia vera (PV) previously treated with phlebotomy and/or conventional cytostatic agents. In each patient, after at least 2 months of discontinuation of any cytotoxic therapy, the hematocrit (Hmt) was first brought to normal value by phlebotomy; IFN-alpha treatment was then begun at a starting dose of 3,000,000 IU s.c. three times a week. Response to treatment, which was assessed monthly, was defined as persistent normalization of Hmt without concomitant phlebotomy; in non-responsive patients the initial IFN-alpha weekly dosage was progressively increased. Twenty patients were responsive with a median duration of response of 7 months (range 2-25+ months); out of these, 7 patients are still under treatment and responsive at 13+, 17+, 20+, 22+, 23+, 25+, 25+ months. These findings indicate that a cohort, although small, of patients with PV (19.4%) are persistently sensitive to IFN-alpha; in this subset of patients, this cytokine can therefore provide a useful treatment option, since, contrary to conventional therapeutic approaches such as radioactive phosphorus, cytostatic agents, or phlebotomy, IFN-alpha is devoid of harmful side effects.

Efficacy and safety of human leucocyte interferon‐α treatment in patients younger than 60 years of age with polycythaemia vera

“…The present study also confirms that interferon is an effective thereapy for PV-associated pruritus, with disappearance or substantial improvement occurring in nine out of 10 patients. These findings are in general agreement with the published data [4][5][6][7][8][9][10][11][12][13][14]. It is noteworthy that pruritus relief was not related to disease duration or interferon dosage, with most of the responses occurring within 4 weeks of treatment.…”

“…Recent reports indicate that recombinant human interferon-␣ (rIFN-␣), a cytokine with in vitro and in vivo antiproliferative activity on haematopoietic stem cells devoid of carcinogenic effect, is capable of inducing and maintaining a complete haematologic remission in patients with PV [4][5][6][7][8][9][10]. In addition, cases of intractable pruritus associated with PV have been found to benefit from interferon-␣ therapy [11][12][13][14].…”

The effect of interferon alpha on myeloproliferation and vascular complications in polycythemia vera

“…Anagrelide might be of limited value in PV, since it selectively lowers platelet numbers but does not influence erythropoiesis and Hct values (20). The low response rate in our patient group, compared to previously published results (7)(8)(9)(10)(11)(12)17,21), might be explained by the difference between patient populations included and moderate IFN alpha doses applied in the present study. Approximately one-third of our patients had to be qualified as "high risk" patients and were therefore pretreated by chemotherapy in addition to phlebotomy.…”

Polycythemia vera in Chinese patients: Thirty-six years of experience

“…Hydroxyurea is a safe agent in Chinese patients with PV. New options in the management of PV with interferon remain to be explored [14,15].…”