Investigational drug Abraxane is active and well tolerated in women with metastatic breast cancer

US Oncology has announced that data presented this week by a network physician at the American Society of Clinical Oncology annual meeting demonstrate that the investigational drug Abraxane™ (albumin nanoparticle paclitaxel), administered weekly without steroid premedication, is active and well tolerated in women with metastatic breast cancer whose disease had progressed while they were treated with paclitaxel (Taxol®) and/or docetaxel (Taxotere®).

Based on analysis to date, results showed a 15 percent (95% CI: 8-22%) overall response rate in 106 patients who received Abraxane 100 mg/m2 administered weekly over 30 minutes a day without premedication for three weeks followed by one week of rest, with a 38 percent probability of surviving 12 months. Additionally, 40 percent of patients were free of disease progression for as long as four months, and almost 30 percent for as long as six months. Ninety-one percent of patients were able to receive the full dose throughout the study without dose reduction.

Joanne Blum, M.D., Ph.D., a US Oncology Principal Investigator at Texas Oncology PA (TOPA), who practices at Charles A. Sammons Cancer Center, Baylor University Medical Center in Dallas, Texas, presented the update. Charles A. Sammons Cancer Center was one of 38 US Oncology affiliated practices that had patients participate in the Abraxane clinical trial.

All patients in the trial, sponsored by American Bioscience, Inc., had progressive metastatic breast cancer while being treated with Taxol or Taxotere in the metastatic setting, or had a relapse within 12 months of adjuvant taxane therapy. The patient population studied had a poor prognosis with 91 percent having visceral (lung and liver) disease, 65 percent with more than three metastatic sites and 88 percent demonstrating ongoing tumor growth while on Taxol or Taxotere.

“The activity of Abraxane and the tolerance of the weekly regimen are impressive in this population of taxane-refractory patients,” said Dr. Joanne Blum, Principal Investigator of the study. “Abraxane differentiates itself from other taxanes because it enables us to administer more cancer-fighting paclitaxel to the patient without an increase in side effects one might expect to see with currently available taxane therapies.”

“It appears that Abraxane allows for more cancer-fighting drug to be given to a patient, more of that drug to actually reach the tumor site in the body, and more of the drug to get inside of the tumor to fight cancer cells.”

The tolerability of the weekly regimen was demonstrated by the finding of <1 percent grade 4 febrile neutropenia and no grade 4 non-hematological toxicities. Grade 3 associated toxicities were few, with <4 percent sensory neuropathy, <3 percent fatigue, <1 percent edema, <1 percent tearing, and no Grade 3 nail changes, myalgia, arthralgia, hypersensitivity or flushing.

A New Drug Application for Abraxane is currently under review by the U.S. Food and Drug Administration. Abraxane is an investigational drug that uses nanoparticle technology to combine paclitaxel – long been considered one of the most effective cancer drugs – with the natural protein “transporter” albumin, avoiding the need for toxic solvents and detergents like those used in Taxol and Taxotere. By eliminating these toxic elements, patients treated with Abraxane do not typically need routine premedications.

The previously reported pivotal Phase III trial demonstrated superior response rate and time to tumor progression in metastatic breast cancer patients versus Taxol.