Clinical phase I study with one-hour paclitaxel infusion

Background: Paclitaxel (PAC) is one of the major anti-cancer drugs,effective in different tumors. Studies with 24-hour infusion with 135mg/m² and a three-hour infusion with 175 mg/m²showed a significant schedule-dependent toxicity. We evaluated a one-hourinfusion schedule within a phase I study to determine the dose limitingtoxicity (DLT), the maximum tolerated dose (MTD), and the anti-cancerefficacy.Patients and methods: Patients with advanced malignant tumors weretreated within cohorts by one-hour infusional paclitaxel starting with 150mg/m² and stepwise escalation with 25 mg/m²increments. Therapy was repeated in three-week intervals. Cycles wererepeated until progression. Toxicity was closely monitored, anti-cancerefficacy was only evaluated in those patients who received at minimum twotreatment cycles.Results: Thirty-four patients entered the study (11 NSCLC, five SCLC,seven ovarian cancer, one cervix cancer, nine MBC, one HN cancer). The MTDwas PAC 250 mg/m². The DLT was central and peripheralneuropathy (WHO grade 3). Other significant toxicities were fatigue,myalgia/arthralgia and paraesthesia. No significant myelotoxicity wasobserved. Totally twentyone patients were evaluable for response. A partialresponse was observed in five (24%) patients (two NSCLC, two ovariancancer, one head and neck cancer). Three (14%) patients had stabledisease and in 13 (62%) patients progressive disease was observed.Conclusions: Paclitaxel 225 mg/m² on day 1 administered asone-hour infusion and repeated every three weeks can be given safely, featuredno relevant myelotoxicity, and is the recommended dose for phase II studies.