Nab-Paclitaxel in Advanced HER2-negative Breast Cancer Patients: Efficacy and Safety Beyond Clinical Trials

Nab-P is widely used in MBC, but limited data from clinical practice are available. This is an open-label, multicentre prospective cohort study prospectively collecting data of MBC pts treated with weekly, or every 3 week administration of Nab-P. For this survey a convenience sample was used. An attempt was made to get at least a sample of 200 pts, which guarantees a standard error of 3.5% for estimation of survival time at 1 year, overall response rate and grade 3-4 toxicity. Overall response rate was 32.1% in the whole population, without any significant difference according to schedule, previous paclitaxel exposure, presence of visceral metastases or line of treatment. Median time to progression was 6 months (95% confidence interval, 1-34), with no differences according to the schedule of treatment. No new data on toxicity were reported. Results from this real life experience suggest that Nab-P can be safely used with both the weekly and the 3-weekly schedule with comparable efficacy, leaving the choice to the physician according to the patient's needs and preference, with a carefully balance between activity and potential toxicity. Background Few data are available regarding efficacy and safety of nanoparticle albumin-bound (nab)-paclitaxel in advanced breast cancer patients outside a controlled trial, especially for the weekly schedule. Patients and Methods We prospectively collected data of advanced breast cancer patients who were candidates to be treated with weekly (125 mg/m2 for 3 consecutive weeks followed by a 1-week rest) or every 3 weeks (260 mg/m2) schedules of nab-paclitaxel, according to physician's decision. Results The study enrolled 209 patients, of whom 92 (39.3%) received weekly nab-paclitaxel. The median age was 58 (range, 31-84) years; 21.8% of the patients were classified as triple-negative breast cancer (estrogen-recetor/progesteron-receptor-negative). The median number of cycles was 5.5. The overall response rate was 32.1% in the whole population, without any significant difference according to schedule, previous paclitaxel exposure, presence of visceral metastases, or line of treatment. The median time to disease progression was 6 months (95% confidence interval, 1-34), with no differences according to the schedule of treatment. Severe adverse events (Grade 3-4) were observed in 60.6% of the patients. The main toxicities were alopecia (53.4%), neutropenia (3%), and sensory neuropathy (2.1%). Conclusion Our real-life data indicate that both schedules of nab-paclitaxel are manageable and safe in advanced breast cancer patients, even if previously treated with other taxanes.