Treatment with Abraxane offers a superior response rate in cases of metastatic breast cancer, and it has a well-tolerated safety profile, claim the companies.

First in Class

Abraxane is the first in a new class of "protein-bound particle" drugs made possible by ABI's proprietary nanoparticle albumin-bound (nab) technology, according to the companies' announcement.

Consisting only of albumin-bound paclitaxel nanoparticles, Abraxane is free of toxic solvents and demonstrated a superior response rate with an almost doubling of the reconciled target lesion response rate when compared with the solvent-based Taxol in a prospectively randomized trial of 460 patients with metastatic breast cancer, the two companies report.

Because it contains no toxic solvents, this next-generation taxane product enables the administration of 50% more chemotherapy with a well-tolerated safety profile, requires no premedication to prevent hypersensitivity reactions, and can be given over 30 minutes using standard IV tubing, says the companies' statement.

Superior Response Rate

"Abraxane provides a much-needed new treatment option for women with metastatic breast cancer," said principal clinical trial investigator William J. Gradishar, M.D., Associate Professor of Medicine, Division of Hematology and Medical Oncology and Co-Director, Lynn Sage Breast Cancer Program at Northwestern Memorial Hospital.

"The pivotal clinical trial results demonstrated that Abraxane had superior response rate when compared to Taxol in patients with metastatic breast cancer. For the first time, we are able to offer patients the full therapeutic benefits of paclitaxel. This makes Abraxane a significant advance in the way we treat breast cancer," Dr. Gradishar said.

"Abraxane has an improved therapeutic index compared to Taxol in the treatment of metastatic breast cancer based on its superior response rate and well-tolerated safety profile," said Joyce A. O'Shaughnessy, M.D., co-director, Breast Cancer Research, and Director, Breast Cancer Prevention, at Baylor-Charles A. Sammons Cancer Center in Dallas, Texas.

No Toxic Solvents

"Patients receiving Cremophor-based taxanes unfortunately are exposed to toxicities caused by the solvent rather than the active chemotherapy drug. The patients with metastatic breast cancer who were treated with Abraxane not only achieved the superior response rate, but they also benefited from the fact that Abraxane does not use toxic solvents to deliver the active drug," Dr. O'Shaughnessy explained.

"Abraxane is an important therapeutic breakthrough since it is an active new class of drugs that addresses the toxicities associated with solvents in taxane-based chemotherapy -- namely, hypersensitivity reactions, severe myelosuppression, prolonged peripheral neuropathy and severe edema," said Edith Perez, M.D., Professor of Medicine, Mayo Clinic College of Medicine, Chair Breast Committee, North Central Cancer Treatment Group.

Culmination of Decade of Research

"Grade 4 neutropenia occurred in less than 10% of the patients. In the patients who developed Grade 3 peripheral neuropathy, rapid improvement occurred after a median of only 22 days. It is significant that Abraxane can be safely administered to both young and elderly patients. Plans currently are underway to study this next-generation taxane in combination with other chemotherapeutic agents in the treatment of front-line metastatic breast cancer," said Dr. Perez.

"The designation of a new protein particle drug class and the approval of Abraxane mark the culmination of over a decade of research in the science of albumin-bound nanoparticles by the ABI team," said Patrick Soon-Shiong, M.D., Executive Chairman of American Pharmaceutical Partners and Chairman, President and Chief Executive Officer of American Bioscience.