A long-term clinical trial of interferon alpha-therapy in essential thrombocythemia

Abstract

In a prospective clinical trial involving six patients suffering from essential thrombocythemia (ET), recombinant human interferon alpha 2b significantly and consistently lowered highly elevated peripheral platelet numbers over long time periods. One patient has now been on continuous treatment for 4 years. During the treatment phase none of the patients suffered from bleeding episodes, thrombosis or disturbances of the microcirculation. The interferon maintenance dose varies considerably from patient to patient, but it is usually much lower than the induction dose. One of the patients had to be withdrawn from the study due to interferon-specific chronic toxicity concomitant with the development of non-neutralizing interferon antibodies. With the exception of one patient, stopping interferon treatment led to an increase in peripheral platelet numbers of up to one million cells per microliter of blood within 4 to 12 weeks. We conclude that interferon alpha can correct peripheral thrombocytosis in selected patients with essential thrombocythemia over a period of years and prevent morbidity attributable to this disease.

Successful Management of Hydroxyurea-induced Leg Ulcers in Essential Thrombocythemia: Report of 3 Cases

“…When they were shifted to interferon therapy (Pegasys®), it maintained good control over their primary disease, comparable to that of HU. This degree of disease control with interferon is in accordance with findings of previous studies, which established that interferon-alpha 2a adequately controls thrombocytosis and vasomotor symptoms in ET [12]. …”

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

“…Our pilot study indicates that interferon therapy alone can be of value in the management of thrombocytosis. This has also been reported from other investigators who found a-interferon to be effective and well tolerated as maintenance therapy in the majority of patients with essential thrombocythemia [7,16,17]. However, the side effects may pose a problem.…”

“…For the most part the dosage has been within tolerable limits with regard to the frequent side effects often seen with this therapy. Long-term treatment results are scarce, but a transient stop in the therapy usually elicits a relapse [7]. Although aspirin, as a single drug treatment, is preferred by many clinicians in younger patients, no trials prove its effect in preventing thromboembolic complications and it poses the possible increased risk of a major hemorrhage.…”

Inflammatory markers in bronchoalveolar lavage fluid of Standardbred racehorses with inflammatory airway disease: response to interferon‐alpha

“…Interferon-alpha (IFNa) has antiviral, antiproliferative and immunomodulatory properties and is used therapeutically in human subjects with chronic viral infection (Onofrio et al 1990), haematological neoplasia (Quesada et al 1983;Foon et al 1984), and immune-mediated disorders (Souillet et al 1989;Middelhoff and Boll 1992). Although IFNa was originally thought to be species specific, equine cells exhibit antiviral and immunomodulatory responses to human IFNa in vitro (Carter 1979;Bridgman et al 1988).…”