Phase I dose-escalation clinical trial with 5-imino-13-deoxydoxorubicin in cancer patients.

Abstract

2575 Background: 5-imino-13-deoxydoxorubicin (DIDOX; GPX-150) is a doxorubicin (dox) analog modified in two locations to prevent formation of a) cardiotoxic metabolites and b) reactive oxygen species. In a rabbit model comparing the cardiotoxicity of dox vs. DIDOX, chronic doses of each caused similar myelosuppression, but only dox caused cardiotoxicity as assessed by echocardiography and histopathology scoring. In view of the non-cardiotoxic nature of DIDOX along with its anticancer efficacy in preclinical studies, DIDOX was entered into a Phase I, open-label, non-randomized dose-finding study in up to 30 patients with solid tumors. Methods: Inclusion criteria included progressing solid tumors and cardiac ejection fraction (CEF) 110% of lower limit of institutional normal (assessed by MUGA). There are 8 dose cohorts and up to 8 cycles/cohort, dosing (iv) once every 3 weeks with an accelerated titration dosing design at the three lowest cohorts. Cohort A =14, B=28, C=56, D=84, E=112, F=150, G=200, and H=265 mg/m2/cycle. Dose was escalated to next dose level if < 1 dose limiting toxicity (DLT) is reported. Maximum tolerated dose (MTD) will be exceeded when 2 or more patients in a cohort elicit DLT; the next lower dose is defined as the MTD. DLT occurs when a decrease in CEF is grade 2 or higher, or grade 4 neutropenia lasts > 5 days. Results: Cohorts A-G have been completed. Number of patients for the cohorts are: A=1, B=1, C=1, D=4 E=3 F=3 G=4, and H = 2 (with 4 more to be enrolled in H). No decrease in CEF occurred in any cohorts. There were no DLTs in cohorts A-G. One patient in H had neutropenia grade 4 for 11 days (a DLT). Another patient in H had neutropenia grade 4 for 4 days. There was no disease progression at the completion of dosing for 6 of the 12 patients in cohorts E-H. In contrast, all 7 patients had disease progression in cohorts A-D. Conclusions: No cardiotoxicity was observed in any patient. No DLT was observed in cohorts A-G. With one DLT in cohort H, one more DLT will define MTD for DIDOX at 200 mg/m2. At higher DIDOX doses (E-H), 6 of 12 patients showed no disease progression. (IND No. 77,051). Clinical trial information: NCT00710125.