Phase I trial of 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG), a heat shock protein inhibitor, administered twice weekly in patients with advanced malignancies

Abstract

Purpose: Phase I dose-escalation study to determine the toxicity and maximum tolerated dose (MTD) of 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG), a heat shock protein 90 (Hsp90) inhibitor, administered on a twice weekly schedule in patients with advanced cancer.

Experimental design: 17-DMAG was administered as a 1- to 2-h infusion twice weekly in 4-week cycles. An accelerated titration design was followed until toxicity was observed, at which point standard dose-escalation proceeded. MTD was defined as the dose at which no more than one of the six patients experienced a dose-limiting toxicity (DLT). Pharmacokinetics were assessed, and Hsp70 mRNA, whose gene product is a chaperone previously shown to be upregulated following the inhibition of Hsp90, was measured in peripheral blood mononuclear cells (PBMCs).

Results: A total of 31 patients received 92 courses of treatment. The MTD was 21mg/m(2)/d; 20 patients were enrolled at this dose level. Nine patients had stable disease for a median of 4 (range 2-22) months. Both C(max) and AUC increased proportionally with dose. The most common toxicities were grade 1 or 2 fatigue, anorexia, nausea, blurred vision and musculoskeletal pain. DLTs were peripheral neuropathy and renal dysfunction. Expression of Hsp70 mRNA in PBMCs was highly variable.

Conclusion: Twice-weekly i.v. infusion of 17-DMAG is well tolerated, and combination phase I studies are warranted.

Fig 1

Mean plasma concentration-time profile for all patients in the MTD cohort (21 mg/m², n = 20). Each circle represents a single sample from a single patient.

Fig 2

Association between ln C_max and ratio of 48 h post-dose/baseline Hsp70 mRNA expression in the MTD cohort (21 mg/m², n = 20).