Escalated cohorts A-H: 27 male or female participants, ages 18-80, BMI 18-36 diagnosed with inoperable, recurrent or metastatic malignant solid tumors, deemed incurable, and who have failed to respond to standard therapy or for whom no standard therapy is available. Eligible subjects will be assigned, successively in order of accrual, to one of eight cohorts, to receive escalating doses of intravenously infused PROMITIL. PROMITIL will be administered as an intravenous infusion. Dose escalation will only proceed in the absence of dose-limiting toxicity (DLT). For this purpose, each cohort will only begin its first cycle of PROMITIL when the cohort preceding it has successfully completed its first 4-week cycle without any signs of DLT.