The data showed that the two antibodies plus docetaxel, given in the neoadjuvant setting prior to surgery, improved the rate of complete tumor disappearance in the breast by more than half compared to Herceptin plus docetaxel.
Genentech said that Neosphere study (Neoadjuvant Study of Pertuzumab and Herceptin in an Early Regimen Evaluation) was a randomised, multicenter, international Phase II study that was conducted at 78 centers worldwide (except the US) in 417 women with newly diagnosed HER2-positive early, inflammatory or locally advanced breast cancer who had never received Herceptin.
The combination of pertuzumab and Herceptin plus docetaxel was not associated with an increase in side effects or cardiac risk compared to Herceptin and chemotherapy.
Based on these findings, Genentech/Roche plans to initiate a Phase III study in HER2-positive early (adjuvant) breast cancer in 2011.
National Cancer Institute in Milan Medical Oncology director Luca Gianni said that the findings of the Neosphere study suggested that this new approach was effective for early HER2-positive breast cancer.
"The combination of Pertuzumab and Herceptin plus chemotherapy had a substantial effect on HER2-positive breast cancer tumors after just four cycles (12 weeks) of neoadjuvant use."