Bortezomib/docetaxel combination therapy in patients with anthracycline-pretreated advanced/metastatic breast cancer: a phase I/II dose-escalation study

The aim of this study was to determine the dose-limiting toxicities (DLTs) and maximum tolerated dose (MTD) of bortezomib plus docetaxel in patients with anthracycline-pretreated advanced/metastatic breast cancer. Forty-eight patients received up to eight 21-day cycles of docetaxel (60–100 mg m−2 on day 1) plus bortezomib (1.0–1.5 mg m−2 on days 1, 4, 8, and 11). Pharmacodynamic and pharmacokinetic analyses were performed in a subset of patients. Five patients experienced DLTs: grade 3 bone pain (n=1) and febrile neutropenia (n=4). The MTD was bortezomib 1.5 mg m−2 plus docetaxel 75 mg m−2. All 48 patients were assessable for safety and efficacy. The most common adverse events were diarrhoea, nausea, alopecia, asthenia, and vomiting. The most common grade 3/4 toxicities were neutropenia (44%), and febrile neutropenia and diarrhoea (each 19%). Overall patient response rate was 29%. Median time to progression was 5.4 months. In patients with confirmed response, median time to response was 1.3 months and median duration of response was 3.2 months. At the MTD, response rate was 38%. Pharmacokinetic characteristics of bortezomib/docetaxel were comparable with single-agent data. Addition of docetaxel appeared not to affect bortezomib inhibition of 20S proteasome activity. Mean alpha-1 acid glycoprotein concentrations increased from baseline at nearly all time points across different bortezomib dose levels. Bortezomib plus docetaxel is an active combination for anthracycline-pretreated advanced/metastatic breast cancer. The safety profile is manageable and consistent with the side effects of the individual agents

A phase I study to repurpose disulfiram in combination with temozolomide to treat newly diagnosed glioblastoma after chemoradiotherapy

Disulfiram, a generic alcohol aversion drug, has promising preclinical activity against glioblastoma (GBM). This phase I study aims to evaluate its safety, maximum tolerated dose (MTD), pharmacodynamic effect, and preliminary efficacy when combined with adjuvant temozolomide in GBM patients after standard chemoradiotherapy. Patients received disulfiram 500–1000 mg once daily, in combination with 150–200 mg/m2 temozolomide. A modified 3 + 3 dose-escalation design was used to determine the MTD. The pharmacodynamic effect of proteasome inhibition was assessed using fluorometric 20S proteasome assay on peripheral blood cells. The MTD was determined based on the dose-limiting toxicities (DLTs) within the first month of therapy. Twelve patients were enrolled to two dose levels: 500 and 1000 mg. Two DLTs of grade 3 delirium occurred after 15 days of administration at 1000 mg per day. Other possible grade 2–3 DSF-related toxicities included fatigue, ataxia, dizziness, and peripheral neuropathy. The toxicities were self-limiting or resolved after discontinuing DSF. The MTD was determined to be 500 mg per day. Limited proteasome inhibition was observed at week 4 and showed an increased trend with escalated disulfiram. Median progression-free survival with 500 mg of DSF was 5.4 months from the start of disulfiram and 8.1 months from the start of chemoradiotherapy. Disulfiram can be safely combined with temozolomide but can cause reversible neurological toxicities. The MTD of disulfiram with adjuvant temozolomide appears to produce limited proteasome inhibition on peripheral blood cells