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 Study of Apolizumab, an Anti-HLA-DR ß-chain Monoclonal Antibody, in Patients With Solid Tumor Malignancies.

BACKGROUND: Human leukocyte antigen (HLA)-DR, a member of the major histocompatibility complex class II antigen family, is a target for antibody-based therapeutics. Apolizumab (Hu1D10, Remitogen), a humanized IgG1 monoclonal anti-HLA-DR ß-chain antibody targets the antigen, 1D10, expressed on a wide variety of hematologic and solid tumor malignancies. In this Phase 1 trial, the maximum tolerated dose and dose-limiting toxicity of weekly apolizumab in patients with advanced solid tumor malignancies were determined. PATIENTS AND METHODS: Eligible patients with refractory solid tumors were initially screened for ID10 Ag on their tumor. Patients whose tumors expressed 1D10 were administered apolizumab 0.5, 1.0, 1.5, or 3.0 mg/kg intravenously over 90 minutes weekly for 4 consecutive weeks, followed by a 4-week break, and assessment of response. Patients whose disease had not progressed were offered additional treatment. RESULTS: Tumors from 75 patients were screened for 1D10 Ag of which 17 patients were positive and underwent treatment. The first 3 dose levels were well-tolerated. Dose-limiting toxicities of grade 3 infusion-related hypersensitivity reactions and grade 3 headache and hypertension occurred in 2 patients, respectively, at apolizumab 3.0 mg/kg. Four patients, 1 each with breast carcinoma, melanoma, renal cell carcinoma, and sarcoma had stable disease for a median of 15 weeks (range: 12 to 19 wk). CONCLUSION: Apolizumab can be administered safely at a maximum tolerated dose of 1.5 mg/kg for 4 consecutive weeks. Adverse events and limited clinical data in both hematologic and solid tumor malignancies resulted in discontinuation of clinical development of apolizumab. HLA-DR remains an interesting immunotherapeutic target.

A phase I study of docetaxel and bexarotene.

BACKGROUND: We conducted a single-arm, dose-escalation, phase 1 clinical trial in order to define the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of bexarotene in combination with docetaxel. METHODS: Patients with solid tumors and no other curative treatment options were eligible. Oral bexarotene was taken daily in combination with docetaxel 25 mg/m(2) administered intravenously on days 1, 8, and 15 of a 28-day cycle. The dose of bexarotene started at 200 mg/m(2) and increased by 100 mg/m(2)/dose level, until either a MTD or the final dose of 400 mg/m(2) was reached. RESULTS: Fifteen patients were enrolled in the study. Median age was 58 years. The majority had non-small-cell lung cancer. The study went to completion without reaching an MTD. Hematological toxicities were mild. Three patients developed grade 3 hypertriglyceridemia, all occurring during the first cycle of treatment. No objective responses were noted. Four patients had stable disease as a best response, 3 with non-small-cell lung cancer and 1 with angiosarcoma. CONCLUSIONS: Treatment was well tolerated and no DLT was seen at docetaxel 25 mg/m(2) and bexarotene 400 mg/m(2). Given that stable disease was durable in 4 patients, future studies with this combination may be warranted.

Phase 1 and pharmacokinetic study of weekly docosahexaenoic acid-paclitaxel, Taxoprexin, in resistant solid tumor malignancies.

PURPOSE: To determine the maximum tolerated dose, dose-limiting toxicity (DLT), and pharmacokinetics of weekly docosahexaenoic acid-paclitaxel (DHA-paclitaxel), a taxane fatty acid conjugate. EXPERIMENTAL DESIGN: Docosahexaenoic acid-paclitaxel was administered by 2-hour i.v. infusion weekly for three out of four weeks. DHA-paclitaxel 200 mg/m(2) was dose escalated by 100 mg/m(2) per cohort to 600 mg/m(2). Blood samples for pharmacokinetics of DHA-paclitaxel and paclitaxel derived from DHA-paclitaxel were collected. RESULTS: Twenty-one patients received 42 cycles of treatment over five dose levels. Grade 3/4 neutropenia occurred in five patients but was not dose limiting. Grade 3 hyperbilirubinemia, a DLT, and grade 1 sensory neuropathy occurred at the highest dose level. PK analyses demonstrated dose proportional C (max) and AUC(0-24). Limited accumulation of DHA-paclitaxel or paclitaxel occurred with weekly treatment. Increased DHA-paclitaxel and paclitaxel AUC(0-24) were associated with increased neutropenia. Of the 19 patients evaluable for response, three patients with esophageal, melanoma and colon carcinoma had stable disease for 11, 16, and 17 weeks, respectively. CONCLUSION: Docosahexaenoic acid-paclitaxel administered weekly to a maximum dose of 600 mg/m(2) was well-tolerated. The slow release of paclitaxel from DHA-paclitaxel and the weekly schedule approximates continuous infusion paclitaxel which may be more active than every 3 week or weekly taxanes.