ABRAXANE-bevacizumab combination therapy may exhibit potential in treatment of triple-negative breast cancers

Abraxis BioScience, Inc. (NASDAQ:ABII), a fully integrated biotechnology company, announced study results today that demonstrate a regimen of ABRAXANE^® (paclitaxel protein-bound particles for injectable suspension) (albumin-bound) given in combination with bevacizumab (Avastin^®) may have potential in the treatment of triple-negative breast cancers. In the pre-clinical study, fifty percent of mice in the combination therapy group>Nab-paclitaxel plus bevacizumab was shown to inhibit tumor growth by 100%, and reduced the incidence of lymph node and lung metastases by 50% and 87%, respectively. The findings were discussed during an oral presentation (Abstract #3852) on April 20 at the 101^st Annual Meeting of the American Association for Cancer Research (AACR) being held in Washington, D.C.

“This model was developed to increase our understanding of hard to treat triple negative breast cancer and improve our ability to develop new treatment approaches targeting this tumor type”

The pre-clinical study established a new model of triple negative breast cancer, HCC1806-RR, double-tagged with Red Fluorescent Protein (RFP) and Renilla luciferase to allow for quantitative assessment of metastatic spread. Mice bearing orthotopic HCC1806-RR tumors of 150mm³ in size were treated with saline (control), bevacizumab (4 mg/kg, i.p., twice a week, for 10 weeks), nab-paclitaxel (10 mg/kg, i.v., qdx5), or with a combination of nab-paclitaxel and bevacizumab. Metastases were analyzed by measuring luciferase activity in the lymph nodes (LN) and lungs.

"This model was developed to increase our understanding of hard to treat triple negative breast cancer and improve our ability to develop new treatment approaches targeting this tumor type," said lead investigator Sophia Ran, Ph.D., Department of Medical Microbiology, Immunology and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL. "This preliminary study demonstrated a high sensitivity to nab-paclitaxel plus bevacizumab, suggesting there may be a role for this combination therapy to significantly improve the health outcome for patients with triple negative breast cancer."

A nab-paclitaxel and bevacizumab combination therapy also increased anti-tumor activity in new models of inflammatory breast cancer (IBC). Given the same dosing regimen, combination treatment inhibited tumor growth in mice by 96% and resulted in 22% (2/9) complete responses.

"These studies establish valuable models for better understanding the biology of these difficult to treat cancers, and indicate that combination therapy utilizing nab-paclitaxel and bevacizumab has potential usefulness in both the triple negative and inflammatory breast cancer populations," said Ran.

In the U.S. ABRAXANE is currently approved for the treatment of breast cancer after failure of combination chemotherapy for metastatic disease or relapse within six months of adjuvant chemotherapy. Prior therapy should have included an anthracycline unless clinically contraindicated. ABRAXANE has also been granted orphan drug designation by the Food and Drug Administration for the treatment of pancreatic cancer as well as stage IIB-IV melanoma.