Phase I Clinical-Labratory Study of the Histone Deacetylase (HDA) Inhibitor MS-275 in Adults With Refractory and Relapsed Hematologic Malignancies

OBJECTIVES:

• Determine the toxic effects and pharmacokinetics of MS-275 in patients with poor-risk hematologic malignancy.
• Determine whether this drug induces changes in hematologic differentiation, in terms of changes in morphology, cell surface marker expression, and acetylation status, in these patients.
• Determine whether this drug induces clinical response in these patients.

OUTLINE: This is a dose-escalation study.

Patients receive oral MS-275 on days 1, 8, 15, and 22. Courses repeat every 6 weeks in the absence of disease progression or unacceptable toxicity.

Cohorts of 3-6 patients receive escalating doses of MS-275 until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which at least 2 of 3 or 2 of 6 patients experience dose-limiting toxicity.