Encouraging response rates have been achieved in women with advanced breast cancer treated with the investigational drug lapatinib, according to a recently published review.

The early results shown by lapatinib are reviewed in the journal Core Evidence, the first international peer-reviewed publication to assess medications by critically evaluating evidence on clinical effectiveness and outcomes.

Breast cancer is the most common cancer affecting women, with approximately 40,000 deaths each year in the US despite advances in detection and treatment. Metastatic disease represents the biggest clinical challenge, with a median survival time of 2 years following diagnosis. The goals of treatment of metastatic breast cancer are to delay disease progression, prolong survival, and optimize quality of life.

More recently, the discovery that some breast cancers carry specific biologic targets has opened up new possibilities to achieve these goals. The targets, known as ErbB receptors, play an important role in cancer development, and targeting them with specific drugs offers a means to maximize efficacy with reduced toxicity.

“Conventional chemotherapy is often associated with poor tolerability,” says Andrew Thomson, PhD, who authored the review, “and endocrine therapy is not an option in women with cancers that are not hormone-responsive. Biologic therapy offers another option.”

The Core Evidence review reveals that between 10 and 38% of women with metastatic breast cancer responded to biologic therapy with lapatinib in phase II trials. The drug was generally well tolerated.

“The best results with lapatinib appear to be in patients overexpressing the markers ErbB2 and/or ErbB1,” said Dr Thomson, “which means it will be possible to target those patients most likely to benefit from treatment.”

Lapatinib, which is being developed by GlaxoSmithKline, is a novel orally administered biologic therapy that inhibits both ErbB1 and ErbB2 receptors. The article noted that there are several phase II and phase III trials underway with lapatinib either alone or in combination with other drugs in patients with metastatic breast cancer. The outcomes of these trials “will be crucial in confirming the potential benefit” of the drug, the article stated.

Published by Core Medical Publishing Ltd (http://www.coremedicalpublishing.com), a new company with offices in Manchester, UK and New York, Core Evidence is the first international peer-reviewed journal to rigorously evaluate the evidence for rational drug selection based on outcomes central to informed medical decision-making, with the goal of improved quality of care.