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Clinical Trials for Mastocytosis

Leukemia Insights - Fall 2009

Obatoclax Mesylate (GX15-070)

Obatoclax Mesylate is a pro-apoptotic medication meaning that it acts to induce cell-death in diseased cells. Therefore it is believed that this medication may influence the growth of abnormal mast cells (but not normal mast cells) and cause them to die. Treatment consists of Obatoclax given intravenously over 3 hours on 3 consecutive days every 2 weeks (2 weeks is considered one cycle of therapy). All treatments must be given at M.D. Anderson Cancer Center. For patients responding to therapy, treatment may be continued as long as therapeutic benefit is derived. Patients who show no response after 5 cycles of therapy will be taken off study.

Selected Inclusion Criteria:

1) Patients with systemic mastocytosis
2) Minimum of two weeks since any major surgery or completion of radiation
3) ECOG performance status 0-2
4) Adequate liver function

Selected Exclusion Criteria:

1) Patients with low blood cell counts (Grade 3 or 4), unless it is known that the low blood cell count is due to systemic mastocytosis.
2) Treatment with any conventional (specifically, interferon or cladribine) or investigational medicine for SM within the preceding 4 weeks
3) Chronic treatment with systemic steroids

Multicenter Phase III Study of Masitinib or Placebo in Mastocytosis with Handicap

Masitinib is a potent inhibitor of KIT, an enzyme (tyrosine kinase) that is important in the biology of mastocytosis and is involved in the activation and growth of mast cells. By blocking KIT, masitinib may slow the growth of mast cells, which may relieve disease related symptoms. The study is open for patients with skin mastocytosis and for patients with systemic mastocytosis that have indolent or smouldering type.

Handicap means that the mastocytosis symptoms are affecting the patient’s health and/or quality of life. This is a multicenter study, but MD Anderson is the only treatment center in the USA participating. If the therapy is proven to be significantly superior to placebo, it is possible that masitinib might be approved by the FDA (Food and Drug Administration). Treatment consists of taking Masitinib or placebo pills daily for 24 weeks. A total of 200 patients will be enrolled: 100 patients will receive Masitinib and 100 will receive a matching placebo. Patients will be treated on an outpatient basis and must return to M.D. Anderson every 4 weeks. The therapy will be provided past 24 weeks if it is beneficial to the patient.

Selected Inclusion Criteria:

1) Patient with Smouldering Systemic Mastocytosis, Indolent Systemic Mastocytosis, or Cutaneous Mastocytosis.
2) Patient with documented treatment failure of his/her handicap(s) with at least one of the following therapies used at optimized dose: Anti H1, Anti H2, Proton pump inhibitor, Osteoclast inhibitor, Cromoglycate sodium, Antileukotriene, other therapies used for the symptomatic care.
3) Handicapped status defined as at least two of the following handicaps, including at least one among pruritus, flushes, depression and asthenia: pruritus score >/= 6, number of flushes per week >/=7, Hamilton rating scale (depression) >/= 10, number of stools per day >/= 4, number of mictions per day >/=8, Fatigue Impact Scale total score (asthenia) >/= 40.
4) ECOG performance status 0-2
5) Patient with adequate organ function
6) Age 18 years and older

Selected Exclusion Criteria:

1) Previous treatment with any tyrosine kinase Inhibitor (e.g. imatinib or dasatinib).
2) Patient who underwent major surgery within 2 weeks prior to study enrollment.
3) < 5 years free of malignancy, except treated basal cell skin cancer or cervical carcinoma in situ
4) Change in the symptomatic treatment of mastocytosis or administration of any new treatment of mastocytosis within 4 weeks prior to baseline

Dr. Srdan Verstovsek is the Leukemia Department’s MPD Program Leader. He can be reached at or 713-745-3429, or feel free to contact any Leukemia physician.

© 2015 The University of Texas MD Anderson Cancer Center