The US Food and Drug Administration (FDA) has approved Abraxane for Injectable Suspension (paclitaxel protein-bound particles for injectable suspension) (albumin-bound) in metastatic breast cancer, American Pharmaceutical Partners, Inc. and American Bioscience, Inc. (ABI) jointly announced here.

Abraxane is indicated for the treatment of breast cancer after failure of combination chemotherapy for metastatic disease or relapse within 6 months of adjuvant chemotherapy. Prior therapy should have included an anthracycline unless clinically contraindicated.

The approval marks a new class of "protein-bound particle" drugs, now made possible by ABI's proprietary nanoparticle albumin-bound (nab) technology. Abraxane is the first in this new class of drugs.

Abraxane, consisting only of albumin-bound paclitaxel nanoparticles, 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. Because it contains no toxic solvents, this next-generation taxane product enables the administration of 50 per cent 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, a company release says.

Principal clinical trial investigator William J. Gradishar, Associate Professor of Medicine, Division of Haematology and Medical Oncology said, "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."

"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," Joyce A. O'Shaughnessy, co-director, Breast Cancer Research, and director, Breast Cancer Prevention, at Baylor-Charles A. Sammons Cancer Centre in Dallas, TX said adding, "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."

"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, Professor of Medicine, Mayo Clinic College of Medicine, Chair Breast Committee, North Central Cancer Treatment Group. "Grade 4 neutropenia occurred in less than 10 per cent 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," Perez added.