[Study of bioequiavailability of paclitaxel for Injection (Albumin Bound) and abraxane and the efficacy of extension treatments in patients with metastatic breast cancer]

Objective: To compare the bioequiavailability of paclitaxel for injection (albumin bound) (PAB) and reference listed drug abraxane in the patients with metastatic breast cancer, and to investigate the safety and efficacy in the extension treatments of PAB. Methods: This study was random, two cycles, self-crossover control study in the bioequiavailability stage. PAB was the investigational drug T and Abraxane was the reference drug R. Patients were randomly assigned to two cycles therapy of either R→T or T→R(260 mg/m(2)/21d). Non-PD patients entered in the extension treatments of the investigational drug PAB(260 mg/m(2)/21d) until the disease progression or the intolerance toxicity. Results: From Mar 1, 2016 to May 24, 2016, we enrolled 40 patients. The blood concentration-time curve and the parameters of pharmacokinetics indicated the two drugs were the bioequivalent drug products in the initial two cycles crossover-therapy.The incidence of adverse drug reactions were 89.7% vs 97.4% in investigational drug vs reference drug and grade 3/4 toxicities were 20.5% vs 21.1%(P=1.000). Patients received a median of 7 treatment cycles(range 1-23) and a median of 260mg/m(2) actual drug dose (range 220-260 mg/m(2)). Seven patients (17.5%) had dose reductions because of toxicities (260 mg/m(2) reduce to 220 mg/m(2)). Twenty-two patients (55%) discontinued treatment prematurely because of toxicity.Overall response rates (ORR) were 40% (95% CI, 24.8%-55.2%). For patients who received PAB as first-line vs non-first-line therapy, the ORR were 43.8% vs 25%. For patients who taxane-naïve vs taxane-pretreated, the ORR were 45.5% vs 37.9%. Median PFS was 49 weeks(95% CI, 30weeks-NA). Conclusion: The paclitaxel for injection (albumin bound) (PAB) and reference listed drug abraxane are the bioequivalent drug products.The toxicity and efficacy of the PAB are similar with abraxane.The more therapy chances for Chinese patients will come by the research and development of domestic drugs.