The addition of the alkylating agent carboplatin, which interfers with the growth of cancer cells, to the standard therapy of Herceptin and paclitaxel greatly extends the time to disease progression for patients with advanced breast cancer, according to research presented at the San Antonio Breast Cancer Symposium.

These preliminary results are from a study evaluating Herceptin (trastuzumab), the chemotherapy drug paclitaxel and carboplatin in HER2-positive metastatic breast cancer patients.

Herceptin, made by Genentech, Inc., is a bioengineered antibody used in patients with metastatic breast cancer who have tumors that overexpress the HER2 protein.

The randomized Phase III trial showed that the addition of carboplatin to Herceptin and paclitaxel resulted in a six-month improvement in the time it takes the disease to progress compared to women who were given the standard Herceptin and paclitaxel regimen.

"This study shows that the addition of carboplatin may provide clinical benefit and demonstrates improvement in response rate and time to disease progression in HER2-positive metastatic breast cancer patients," said Dr. Nicholas Robert of Inova Fairfax Hospital in Virginia and lead investigator. "In addition, the preliminary analysis of survival is encouraging."

The study included 194 women who had evidence of HER2 protein overexpression; 191 patients were evaluated for the time it took their breast cancer to progress.

Results of the randomized study showed that patients given Herceptin, paclitaxel and carboplatin had an average time to disease progression of 11.2 months, compared to 6.9 months for women given the standard therapy of Herceptin and paclitaxel.

The average survival in the Herceptin and paclitaxel group was 33.5 months and has not been reached at 36 months of follow-up in the Herceptin, paclitaxel and carboplatin group.

"We're pleased that the Herceptin/paclitaxel/carboplatin combination showed additional benefit in women with HER-2-driven disease," said Dr. Gwen Fyfe, Genentech's vice president of Oncology, Medical Affairs. "This is important because patients with HER2-positive breast cancer have an aggressive form of the disease that is associated with more rapid cancer progression and shortened survival."

Other sources: Genetech