α‐2a interferon therapy and antibody formation in patients with essential thrombocythemia and polycythemia vera with thrombocytosis

Abstract

In ten patients with essential thrombocythemia and polycythemia vera with thrombocytosis we have investigated the therapeutic effect of recombinant alpha-2a interferon (Roceron-A) given subcutaneously in a maintenance dosage of 3 million units three times weekly. The aim was to normalize the platelet count (< or = 400 x 10(9)/L). One of the secondary aims was to study platelet activity measured as beta-thromboglobulin (beta-TG) in urine. All but one patient could administer the injections and in all patients a significant reduction in platelet values was seen. The treatment was discontinued in three patients due to side effects of interferon, two because of hair loss (one with irreversible alopecia), and one because of depression. Three patients developed antibodies to alpha-2a interferon and a concomitant rise in the platelet level; in one patient therapy was switched to leukocyte alpha-interferon with an excellent response. The initial levels of beta-TG were elevated in 9/10 patients and were significantly reduced at 6 months in 4/5 patients not developing antibodies. Six patients are still on alpha-interferon therapy with a long-term follow-up of 3-3.5 years. We conclude that alpha-interferon therapy may be an alternative in patients with thrombocytosis and/or complications necessitating treatment.

Long term treatment of myeloproliferative disease with interferon-?-2b

“…Other benefits of rIFN‐α therapy noted in studies of PV patients include decreased splenomegaly,40‐43 reduced risk of thrombosis, and remittance of intractable pruritus 36, 39, 44, 45. Reduced platelet counts with relief of clinical symptoms also have been reported in series of patients with ET receiving rIFN‐α therapy 38, 46‐49. Among patients with myeloid metaplasia, responses to rIFN‐α therapy have been more variable 21, 22, 50‐52.…”

“…Within the past 7 years, an increasing number of reports have been published suggesting a potential therapeutic role for rIFN‐α therapy in the management of other variants of MPD. Several investigators have reported that rIFN‐α treatment resulted in hematologic control accompanied by a reduced need for phlebotomy in a relatively large proportion of patients with PV 36‐40. Other benefits of rIFN‐α therapy noted in studies of PV patients include decreased splenomegaly,40‐43 reduced risk of thrombosis, and remittance of intractable pruritus 36, 39, 44, 45.…”

Microvascular Disturbances, Thrombosis, and Bleeding in Thrombocythemia: Current Concepts and Perspectives

“…105 Another recently recognized problem is the development of neu tralizing antibodies in some patients under treatment. 106 Other, more unusual adverse effects of IFN are central nervous system effects, including neuropsychiatric manifestations, gastrointestinal side effects, and exacer bation or development of autoimmune diseases. Elliott and Tefferi point out that hydroxyurea is teratogenic in animals and the safety of anagrelide in pregnancy is unproven; therefore, IFN-α may be the best option if ther apy is needed to control thrombocytosis during preg nancy.…”