HER2+ breast ca mortality lowered with trastuzumab: 'the risk of cardiac toxicity remains low.'.(News)

ATLANTA -- New results from the international Herceptin Adjuvant (HERA) trial show that taking trastuzumab for 12 months after standard chemotherapy significantly reduced the risk of death for early-stage HER2-positive breast cancer patients.

At a median follow-up of 2 years, 1,703 patients treated with trastuzumab (Herceptin), a monoclonal antibody, also continued to have better disease-free survival, compared with 1,698 patients in the observation arm of the study.

Risk of cardiotoxicity remained low in the updated data presented by Dr. Ian Edward Smith at the annual meeting of the American Society of Clinical Oncology.

The researchers for the phase III trial, conducted by the Swiss-based Roche pharmaceutical company and the Breast International Group (BIG), previously reported a disease-free survival benefit based on 1-year data (N. Engl. J. Med. 2005;353:1659-72). They have yet to report on a third arm of the study that randomized 1,694 women to 24 months of adjuvant therapy with trastuzumab.

In a discussion of the data, Dr. Clifford A. Hudis described HERA and other studies of adjuvant trastuzumab as "amazingly consistent." Trastuzumab's value is established, but the best way to incorporate it into therapy for early-stage human epidermal growth factor receptor 2 (HER2)-positive patients needs to be resolved, said Dr. Hudis, chief of the breast cancer service at Memorial Sloan-Kettering Cancer Center, New York.

In the 2-year data reported by Dr. Smith, head of the breast unit at Royal Marsden Hospital in London, an intent-to-treat analysis found that 92.4% of the trastuzumab arm and 89.7% of the observation group were alive at 3 years (hazard ratio [HR] 0.66). Disease-free survival was 80.6% in the trastuzumab arm and 74.3% in the observation group (HR 0.64).

Dr. Smith reported similar results in a censored analysis that did not count 861 observation arm patients who switched to trastuzumab after the first-year results were announced last year.