OBJECTIVES: I. Determine toxicities and pharmacokinetics of oral R115777 in adults with refractory acute leukemia or accelerated or blastic phase chronic myelogenous leukemia. II. Determine the effect of R115777 on farnesylation within leukemia cells. III. Determine any clinical response (at least 50% decrease in circulating leukemia cells) to R115777 by these patients.