Advanced breast cancer; improving chemotherapy treatment

The authors aimed to evaluate a series of treatments used for advanced breast cancer; this was a review of chemotherapy drugs such as paclitaxel (Taxol), doxetaxel (Taxotere) and nab-paclitaxel (Abraxane). 

Taxanes are a group of chemotherapy drugs used commonly in locally advanced (cancer has spread into nearby tissue and lymph nodes) and metastatic (cancer has spread to distant organs) breast cancer. They prevent tumor growth by stopping cancer cells dividing and multiplying. Paclitaxel and docetaxel are commonly used treatments, however, they can be associated with toxic side-effects.

Nanoparticle albumin-bound (nab)-paclitaxel is a nanoparticle (a drug particle on an extremely miniscule scale). New research indicates that this drug may be more efficient due to improved drug delivery.

Over 760 patients with metastatic breast cancer (the cancer has spread to other organs) were evaluated over the course of this review.

In one study of 460 patients, 33% ofpatients receiving nab-paclitaxel achieved a response (some or complete disappearance of signs and symptoms of cancer; 33%) compared with 19% of those receiving paclitaxel. Patients also had a 25% reduced likelihood of cancer progression when taking nab-paclitaxel. 

In another study of 302 patients, various doses of nab-paclitaxel were evaluated compared to docetaxel. The authors concluded that 150 mg/m2 of nab-paclitaxel was the ideal dose, with 49% of these patients achiving a response compared to 35% of those receiving docetaxel. Progression-free survival (length of time until cancer worsens) was longer in the nab-paclitaxel group (12.9 months) compared to those who received docetaxel (7.5 months). Overall survival was found to be significantly longer in the nab-paclitaxel group (33.8 months) compared to the docetaxel group (26.6 months). 

Assessment of the safety of nab-paclitaxel in a study of 454 patients showed a reduction in treatment side-effects. Severe neutropenia (a low count of neutrophils – a white blood cell that helps fight infections) was significantly less frequent in patients receiving nab-paclitaxel (9%) than paclitaxel (22%) and docetaxel (75%). Febrile neutropenia (the additional development of a fever with neutropenia) was also significantly higher in patients treated with docetaxel than nab-paclitaxel.

The authors concluded that nab-paclitaxel is a safer and more efficient treatment drug for metastatic breast cancer compared to both paclitaxel and docetaxel.

Celgene, the manufacturers of nab-paclitaxel funded the scientific meetings that occurred throughout this study, as well as the scientific writing involved in the study.