A Phase I Trial of the ABCB1 Inhibitor, Oral Valspodar, in Combination With Paclitaxel in Patients With Advanced Solid Tumors.

OBJECTIVES: Multidrug resistance mediated by P-glycoprotein is a potential obstacle to cancer treatment. This phase 1 trial determined the safety of paclitaxel with valspodar, a P-glycoprotein inhibitor, in patients with advanced solid tumors. METHODS: Patients were treated with single-agent paclitaxel Q3W 175 mg/m 2 (or 135 mg/m 2 if heavily pretreated) as a 3-hour infusion. If their disease was stable (SD) or progressive (PD), paclitaxel at 30% (52.5 mg/m 2 ), 40% (70 mg/m 2 ), or 50% (87.5 mg/m 2 ) of 175 mg/m 2 (full dose) was administered with valspodar 5 mg/kg orally 4 times daily for 12 doses. Pharmacokinetic sampling (PK) for paclitaxel and valspodar was performed during single-agent and combination therapy. RESULTS: Sixteen patients had SD/PD after one cycle of paclitaxel and then received paclitaxel at 30% (n=3), 40% (n=3), and 50% (n=10) with valspodar. Hematologic adverse events (AEs) including myelosuppression at paclitaxel 40% were comparable to those of full-dose paclitaxel. Non-hematologic AEs consisted of reversible hepatic (hyperbilirubinemia and transaminitis) and neurologic AEs (ataxia and paresthesias). Eleven patients experienced SD with a median of 12.7 weeks (range, 5.4 to 36.0), 4 patients progressed, and 1 was inevaluable. Reduced dose paclitaxel with valspodar resulted in lower plasma peak concentrations of paclitaxel; otherwise, concentrations were similar to single-agent paclitaxel. CONCLUSION: Paclitaxel at 70 mg/m 2 was administered safely with valspodar. Limited efficacy in hematologic and solid tumors resulted in discontinuation of its clinical development and other transporter inhibitors. Recently, the development of ATP-binding cassette transporter inhibitors has been reconsidered to mitigate resistance to antibody-drug conjugates.

A phase I trial of docetaxel and vinorelbine in patients with advanced non-small cell lung cancer.

Advanced non-small cell lung cancer (NSCLC) remains a difficult cancer to treat, and evolution of platinum-free regimens in a first-line setting is ongoing. This was a dose-finding study on the docetaxel and vinorelbine combination. Docetaxel was given at 60 mg/m(2) on day 1 only, and vinorelbine was given on days 1 and 15 starting at 20 mg/m(2), then escalated to 30 and 40 mg/m(2) in two dose cohorts. Each cycle lasted 28 days. The maximum tolerated dose was 60 mg/m(2) docetaxel and 30 mg/m(2) vinorelbine. Twenty-one patients were enrolled and showed an overall response rate of 9.5%, with stable disease documented in 33% of patients. The dosage schedule of this combination resulted in acceptable toxicities. The median time to progression was 5.86 months (95% CI 2.50-9.22), and median survival was 10.96 months (95% CI 1.42-20.51) with a 1-year survival rate of 50%. This combination may be important for patients with NSCLC.

Phase I study of docetaxel in combination with the P-glycoprotein inhibitor, zosuquidar, in resistant malignancies.

PURPOSE: To determine the maximum tolerated dose, dose-limiting toxicity, and pharmacokinetics of docetaxel infused over 1 hour when given in combination with oral zosuquidar to patients with resistant solid tumors. EXPERIMENTAL DESIGN: In cycle 1, patients received docetaxel alone. In subsequent cycles, zosuquidar was administered with docetaxel, which was escalated from 75 to 100 mg/m2. Zosuquidar was escalated from 100 to 300 mg/m2 every 8 hours on days 1 to 3 for a total of 7 doses, or from 400 to 500 mg every 12 hours for 2 doses administered 2 hours before docetaxel. The pharmacokinetics of docetaxel with and without zosuquidar administration were obtained. RESULTS: Thirty-six of 41 patients completed at least one cycle of docetaxel and zosuquidar. The maximum tolerated dose was docetaxel 100 mg/m2 and zosuquidar 500 mg every 12 hours for 2 doses. The most common toxicity was neutropenia. In 35 patients, zosuquidar produced minimal increases in the docetaxel peak plasma concentrations and area under the curve. Dosing over 3 days with zosuquidar (7 doses) did not show benefit over the 1-day dosing. Of the 36 patients, one patient had a partial response, and 14 patients had disease stabilization. CONCLUSIONS: Docetaxel at 75 or 100 mg/m2 and zosuquidar 500 mg 2 hours before docetaxel and 12 hours later is well tolerated. Zosuquidar minimally alters the pharmacokinetics of docetaxel, allowing full dose docetaxel to be given with this P-glycoprotein modulator. A Phase II study with this combination in advanced breast carcinoma is underway.

Phase I study of pegylated liposomal doxorubicin and gemcitabine in patients with advanced malignancies.

BACKGROUND: Pegylated liposomal doxorubicin (PEG-LD) and gemcitabine have single-agent activity in breast and ovarian carcinoma patients. We conducted a Phase I trial to evaluate the maximum tolerated dose (MTD) and toxicities of this combination in patients with advanced malignancies. METHODS: Twenty-six patients with refractory or recurrent malignancies were enrolled in this dose escalation trial. Dose escalation proceeded from a starting level of PEG-LD 20 mg/m(2) and gemcitabine 1000 mg/m(2) administered on Days 1 and 15 of a 28-day cycle. RESULTS: The MTD was PEG-LD 20 mg/m(2) and gemcitabine 2000 mg/m(2) administered on Days 1 and 15 of a 28-day cycle. Dose-limiting toxicity, a Grade 3 rash, was observed in one patient during Cycle 1 and Grade 3 stomatitis and a rash were observed in a second patient during Cycle 2 after administration of PEG-LD 25 mg/m(2) and gemcitabine 2000 mg/m(2). Other side effects included palmar-plantar erythrodysesthesia, nausea, and fatigue. One complete and two partial responses were observed. CONCLUSIONS: The recommended Phase II dose is PEG-LD 20 mg/m(2) with gemcitabine 2000 mg/m(2) on Days 1 and 15 of a 28-day cycle. A trial with this combination is currently ongoing at this institution comprising patients with refractory ovarian carcinoma.

Phase I dose and sequencing study of pegylated liposomal doxorubicin and docetaxel in patients with advanced malignancies.

BACKGROUND: Pegylated liposomal doxorubicin (PEG-LD) and docetaxel have single-agent activity in several malignancies. The authors conducted a Phase I trial to evaluate the maximum tolerated dose (MTD), toxicities, and effect of dose sequencing of this combination in patients with advanced malignancies. METHODS: Twenty-two patients were enrolled in this two-arm, accelerated, dose escalation trial. Both drugs were administered on Days 1 and 15 of a 28 day cycle. In Arm A, dose escalation proceeded from a sequence and starting dose of 15 mg/m(2) PEG-LD and 30 mg/m(2) docetaxel. In Arm B, dose escalation proceeded from a sequence and starting dose of 30 mg/m(2) docetaxel and 15 mg/m(2)PEG-LD. In both arms, the dose of each drug was increased alternately by 5 mg/m(2) at each dose level. RESULTS: The MTD for Arm A was 20 mg/m(2) PEG-LD and 40 mg/m(2) docetaxel, both of which were administered on Days 1 and 15 of a 28-day cycle. The MTD for Arm B was 35 mg/m(2) docetaxel and 20 mg/m(2) PEG-LD, both of which were administered on Days 1 and 15 of a 28-day cycle. Dose-limiting toxicities were Grade 3 (according to the National Cancer Institute Common Toxicity Criteria) skin toxicity and thrombocytopenia. One partial response was observed and stable disease was documented for three patients. CONCLUSIONS: The recommended sequence and dose is 20 mg/m(2) PEG-LD followed by 40 mg/m(2) docetaxel on Days 1 and 15 of a 28-day cycle in Phase II trials for patients with breast and ovarian carcinoma to establish the efficacy of this well tolerated regimen.