A phase I trial combining motexafin gadolinium with docetaxel in the treatment of advanced solid tumors

Abstract

3203 Background: Motexafin gadolinium (Xcytrin) is a novel therapeutic that concentrates in tumors and generates reactive oxygen species. Pre-clinical models show that motexafin gadolinium enhances in tumors the cytotoxic activity of selected chemotherapies, including taxanes. This phase I trial treated patients with combined motexafin gadolinium and docetaxel. Methods: Patients with advanced solid tumors, adequate bone marrow, hepatic and renal function were eligible. Cohorts of 3 pts were treated with motexafin gadolinium, starting at 2.5 mg/kg followed 30 minutes later by docetaxel 75 mg/m2. Treatments were repeated q3wks. The primary objective was to determine the maximum tolerated dose (MTD) of the combination on this schedule and to determine the dose limiting toxicities (DLT). The secondary objective was to evaluate the response rate of tumors to the treatment regimen. Motexafin gadolinium dose was escalated in successive cohorts while docetaxel dose remained fixed. Results: Six pts were treated at motexafin gadolinium (2.5- 5mg/kg). There were 2 males/4 females with a median age of 68.5 yrs (range 53–76). Diagnoses included prostate (1); ovarian (2); lung (2); breast (1). Pts had had a median of 1 prior chemotherapy regimens (range 1–13), 5 pts had previously received a taxane. Reported toxicities in more than one patient include urine discoloration from excretion of motexafin gadolinium, fatigue, diarrhea and nausea, but DLT has yet to be defined. Responses are reported as follows: PR by CT in breast and by PSA in prostate, SD in lung, and PD in ovarian ca. Conclusion: Motexafin gadolinium in combination with docetaxel is feasible and did not increase docetaxel toxicity at the doses used, and may show clinical benefit as the study continues. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Pharmacyclics, Inc. Pharmacyclics, Inc. Pharmacyclics, Inc. Pharmacyclics, Inc.