A phase I study of intravenous TZT-1027 administered on day 1 and day 8 of a three-weekly cycle in combination with carboplatin given on day 1 alone in patients with advanced solid tumours

Background: TZT-1027 is a tubulin-binding drug and synthetic derivative of dolastatin-10 with cytotoxic and antivascular activity in vitro and in vivo. Studies have demonstrated anti-tumour activity in several tumour types. Methods: Patients were treated with escalating doses of TZT-1027 and carboplatin at doses from 1.6 to 2.0 mg/m2 and AUC 4 and 5 respectively. For pharmacokinetic analysis, plasma sampling was done during the first course using a high-performance liquid chromatographic assay. Results: 14 patients received a total of 55 cycles at three dose levels. Dose limiting toxicities (DLTs) were first observed with 1.6mg/m2 TZT-1027 and carboplatin AUC 5; 1 patient had grade 4 neutropenia and a delay in day 8 treatment occurred in two patients (gr 2 fatigue, gr 3 diarrhoea). At TZT-1027 2 mg/m2 and carboplatin AUC 5, one patient experienced grade 3 paralytic ileus. The most frequent toxicities were neutropenia, anaemia, fatigue, constipation, infection and vomiting. Peripheral neuropathy was reported in 36% of patients. One patient (pancreatic adenocarcinoma) achieved a partial response lasting 181 days. Pharmacokinetic analysis did not demonstrate any interaction between TZT-1027 and carboplatin. Conclusions: The recommended phase II dose is TZT-1027 1.6mg/m2 and carboplatin AUC 5. No evidence of a PK interaction between these agents was observed.