Genexol®-PM is a Cremorphor EL (CrEL)-free polymeric micelle formulation of paclitaxel that allows higher-dose administration with less hypersensitivity. This study was conducted to evaluate the response and safety of Genexol®-PM monotherapy in patients with recurrent or metastatic breast cancer (MBC).
A total of forty-eight patients with recurrent or MBC, ECOG performance status ≤ 2 received Genexol®-PM by intravenous infusion at 300 mg/m2 over 3 h every 3 weeks in the inpatient setting with premedication until disease progression or intolerability. Response to therapy was assessed after every 3 cycles using the Response Evaluation Criteria in Solid tumors (RECIST) guideline (version 1.1) and adverse events were evaluated according to the NCI Common Terminology Criteria for Adverse events, Version 3.0.
A total of 290 chemotherapy cycles were administered, with a median of 6 cycles per patient (range, 1–16). The overall response rate was 52.1% with 1 complete response (CR) and 24 partial responses (PR). Of 11 patients who received Genexol®-PM as a first-line therapy, there were 5 responses (45.5%). Disease control rate (CR + PR + stable disease) was 64.6% (first-line: 72.7%, second-line: 53.8%, respectively). The median time to progression (TTP) was 6.0 months (range, 2.0–36 months). The common grade 3/4 non-hematologic toxicities were peripheral neuropathy (n = 22, 45.8%) and myalgia (n = 5, 10.4%). Hematologic toxicities were grade 3 and 4 neutropenia (n = 15, 31.3% and n = 6, 12.5%, respectively), and grade 1 and 2 thrombocytopenia (n = 7, 14.6%). No febrile neutropenia was observed.
Genexol®-PM, a CrEL-free, polymeric micelle formulation of paclitaxel chemotherapy showed significant antitumor activity with relatively low incidence and severity of toxicity in spite of a high paclitaxel dose in patients with MBC. Although further studies with larger sample size and different dosing schedules are warranted, this study suggests that Genexol®-PM monotherapy may be a candidate as a reasonable treatment for MBC patients.
Clinical trial identification
Legal entity responsible for the study
Sung Soo Kang.
Has not received any funding.
The author has declared no conflicts of interest.