OBJECTIVES: I. Determine the maximum tolerated dose (MTD) of MEN-10755 in patients with recurrent or refractory adult solid tumors. II. Determine the qualitative and quantitative toxic effects of MEN-10755 and study the predictability, duration, intensity, onset, reversibility, and dose relationship of the toxic effects in these patients. III. Propose a safe dose for phase II study. IV. Assess the pharmacokinetics of MEN-10755 at different dose levels in these patients. V. Document any possible antitumor activity of MEN-10755.