title: Interferon alpha therapy for patients with essential thrombocythemia: final results of a phase II study initiated in 1986.
abstract: BACKGROUND
  In 1986, a Phase II trial of recombinant interferon-alpha (IFN-alpha) was initiated as therapy for patients with essential thrombocythemia (ET).
  
  
  METHODS
  Patients were treated with subcutaneous IFN-alpha at a dose of 5 x 10(6) units/m(2) daily. In responding patients, the therapy lasted at least 3 years.
  
  
  RESULTS
  Twenty-three patients (14 females and 9 males; median age, 41 years; age range, 20-63 years) with a median platelet count of 1350 x 10(9)/L were treated. After a median follow-up of 174 months (14.5 years), 15 of 20 evaluable patients (75%) responded, including 14 patients who achieved a complete hematologic response (CHR) (6 of them with bone marrow remission) and 1 patient who demonstrated a partial response. The median time to response was 6 months (range, 0.5-36 months), and the median response duration was 48 months (range, 5-114 months). Seven patients who achieved a CHR and were taken off therapy after they completed 3 years of maintenance therapy sustained their response for a median of 28 months. No symptoms or signs of thrombosis or hemorrhage were observed in responding patients. Eleven of 14 patients (78%) who achieved a CHR developed a recurrence, and 2 of 5 patients with recurrences who were rechallenged with IFN-alpha achieved a second response. The treatment was tolerated relatively well.
  
  
  CONCLUSIONS
  IFN-alpha was safe and effective therapy for patients with ET, and the ability of IFN-alpha to reverse disease pathology and possibly modify the clinical course of patients with ET warrants its investigation in larger, prospective trials.
authors.affiliation: Department of Leukemia, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
authors.forename: Rashid
authors.initials: R
authors.lastname: Saba
authors.forename: Elias
authors.initials: E
authors.lastname: Jabbour
authors.forename: Francis
authors.initials: F
authors.lastname: Giles
authors.forename: Jorge
authors.initials: J
authors.lastname: Cortes
authors.forename: Moshe
authors.initials: M
authors.lastname: Talpaz
authors.forename: Susan
authors.initials: S
authors.lastname: O'Brien
authors.forename: Emil J
authors.initials: EJ
authors.lastname: Freireich
authors.forename: Guillermo
authors.initials: G
authors.lastname: Garcia-Manero
authors.forename: Hagop
authors.initials: H
authors.lastname: Kantarjian
authors.forename: Srdan
authors.initials: S
authors.lastname: Verstovsek
mesh_terms: D000328:Adult; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D007279:Injections, Subcutaneous; D007370:Interferon Type I / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011994:Recombinant Proteins; D012074:Remission Induction; D013922:Thrombocytosis / Q000188:drug therapy*
chemical_list: D000970:Antineoplastic Agents; D007370:Interferon Type I; D011994:Recombinant Proteins