After the long process of designing, developing and testing new drugs, these meds are usually far more expensive than the older medications on the market. Are they better? Not always.

A phase III trial has concluded that two new, significantly more costly drugs – nanoparticle albumin bound (“nab”) Abraxane (paclitaxel) and Ixempra (ixabepilone) – are no more effective in treating metastatic cancer than the standard chemotherapy – paclitaxel.

In fact, paclitaxel is superior to ixabepilone in extending the length of time before the disease continues its march (progression-free survival – PFS) and less toxic than nab-paclitaxel.

Lead study author Hope S. Rugo, MD, professor of medicine and director of breast oncology and clinical trials education at the University of California, San Francisco, explained, “In metastatic breast cancer, we are constantly examining and refining dosing schedules, testing new therapies, and looking closely at molecular characteristics of patients’ tumors to find the right treatment for the right patient, with the fewest toxicities.” 

For this study, 799 patients were assigned to receive weekly doses of one of the three therapies – paclitaxel, nab-paclitaxel or ixabepilone. The regimens included three weeks of treatment, followed by a week off. 

Most of the patients also received Avastin (bevacizumab), which became optional in March 2011. 

Here’s what the researchers found: 

• Median time before the disease began to progress was 10.6 months for paclitaxel, 9.2 months for nab-paclitaxel, and 7.6 months for ixabepilone.
• Ixabepilone was substantially less effective than paclitaxel and nab-paclitaxel was not better than the standard paclitaxel.
• Serious non-blood related toxicities were lowest for paclitaxel.
• Blood-related toxicity was lowest in the ixabepilone arm and highest in the nab-paclitaxel group.

Dr. Rugo said, “This study demonstrates that we should not simply assume that newer drugs are always better than the standard therapies.” 

The study is also looking at the biological behavior of these drugs to determine which patients might benefit most from the individual therapies. Results from these studies have yet to be reported.

Findings from this research were presented at the 48th American Society of Clinical Oncology meeting. Research is considered preliminary before it’s published in a peer-reviewed journal.

Several authors disclosed receiving research funding or consultancy fees from pharmaceutical companies, including: Abraxis BioScience; Bristol-Myers Squibb; Roche/Genentech.