title: Recombinant interferon-alpha therapy of Philadelphia chromosome-negative myeloproliferative disorders with thrombocytosis.
abstract: OBJECTIVE
  The clinical course of patients with myeloproliferative disorders and excessive thrombocytosis may be complicated by serious hemorrhagic or thrombotic events. We have previously reported that interferon-alpha can control severe refractory thrombocytosis in patients with advanced chronic myelogenous leukemia. Therefore, we treated a group of thrombocythemic patients with Ph-negative myeloproliferative disorders, including polycythemia vera and essential thrombocythemia, with recombinant interferon-alpha (rIFN-alpha 2a).
  
  
  METHODS
  Eight patients with profound elevations in platelet counts received a median induction dose of 5.4 X 10(6) U/day (range, 5.0 to 10.0 X 10(6) U/day) of rIFN-alpha 2a administered intramuscularly or subcutaneously.
  
  
  RESULTS
  We observed a significant decline in platelet counts from a median baseline value of 1,929 X 10(9)/L (range, 960 to 2,960 X 10(9)/L) to a median posttreatment value of 431 X 10(9)/L (range, 71 to 1,150 X 10(9)/L) (p less than 0.01). Concomitantly, white blood cell counts declined from a median baseline value of 20.8 X 10(9)/L (range, 10.5 to 40.8 X 10(9)/L) to a median posttreatment value of 6.1 X 10(9)/L (range, 2.9 to 29.0 X 10(9)/L) (p less than 0.02). Correction of thrombocytosis was rapid, with a median of only eight days from the start of therapy to the achievement of a platelet count less than 1,000 X 10(9)/L. Six of eight patients have shown an ongoing response with a median follow-up period of 11 months (range, one to 30 months). There have been no bleeding or thrombotic events during the study. Side effects of rIFN-alpha 2a therapy consisted of fever and flu-like symptoms, with tachyphylaxis developing after one to two weeks of therapy.
  
  
  CONCLUSIONS
  Our observations suggest that alpha interferon may be a promising therapeutic agent for myeloproliferative disorders characterized by thrombocytosis.
authors.affiliation: Department of Clinical Immunology and Biological Therapy, University of Texas, M.D. Anderson Cancer Center, Houston 77030.
authors.forename: M
authors.initials: M
authors.lastname: Talpaz
authors.forename: R
authors.initials: R
authors.lastname: Kurzrock
authors.forename: H
authors.initials: H
authors.lastname: Kantarjian
authors.forename: S
authors.initials: S
authors.lastname: O'Brien
authors.forename: J U
authors.initials: JU
authors.lastname: Gutterman
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007370:Interferon Type I / Q000009:adverse effects / Q000627:therapeutic use*; D007958:Leukocyte Count; D008214:Lymphocytes / Q000032:analysis; D008297:Male; D008875:Middle Aged; D009196:Myeloproliferative Disorders / Q000188:drug therapy*; D010976:Platelet Count; D011087:Polycythemia Vera / Q000188:drug therapy; D011994:Recombinant Proteins; D013920:Thrombocythemia, Essential / Q000188:drug therapy
chemical_list: D007370:Interferon Type I; D011994:Recombinant Proteins