Bone marrow effects of anagrelide therapy in patients with myelofibrosis with myeloid metaplasia

Br J Haematol. 1999 Sep;106(3):682-8. doi: 10.1046/j.1365-2141.1999.01598.x.


In a prospective study investigating the therapeutic role of anagrelide in myelofibrosis with myeloid metaplasia, 20 patients received anagrelide in daily oral doses of 0.5-3 mg. 17 patients were evaluable and received anagrelide for a median of 2 years (range 0.5-4 years). No patient had a clinically appreciable benefit. Bone marrow (BM) examinations at baseline and after 6 and 12 months of treatment were available for 17, 17 and 12 patients, respectively. In all evaluable cases, BM megakaryocyte number increased after 6 months of anagrelide treatment. Also, Ulex europaeus agglutinin-1 staining of megakaryocytes revealed a left-shifted maturation pattern in most patients with a platelet response to anagrelide. However, megakaryocyte staining intensity for transforming (TGF-beta) and platelet-derived (PDGF) growth factors was not affected consistently by treatment. No patient had a >/=2 grade change in either BM fibrosis or osteosclerosis. These in-vivo data support our previous in-vitro observations that anagrelide interferes with megakaryocyte maturation rather than proliferation. Lack of a positive treatment effect is consistent with the finding that anagrelide did not significantly alter megakaryocyte expression of TGF-beta and PDGF.

MeSH terms

  • Aged
  • Blood Platelets / drug effects
  • Female
  • Humans
  • Male
  • Middle Aged
  • Platelet Aggregation Inhibitors / therapeutic use*
  • Platelet Count
  • Primary Myelofibrosis / complications
  • Primary Myelofibrosis / drug therapy*
  • Primary Myelofibrosis / pathology
  • Prospective Studies
  • Quinazolines / therapeutic use*


  • Platelet Aggregation Inhibitors
  • Quinazolines
  • anagrelide