Adding trastuzumab to preoperative chemotherapy significantly increases response to therapy and likelihood of successful breast-conserving surgery in patients with locally advanced HER2-positive breast cancer, according to first-stage results of a phase III study presented at the annual meeting of the American Society of Clinical Oncology.

"HER2-positive breast cancer remains a serious clinical diagnosis, as many patients will experience disease recurrence and progression. Neoadjuvant chemotherapy is administered to patients to help render inoperable tumors removable" said Professor L. Gianni, Director of Medical Oncology, Fondazione IRCCS Istituto Nazionale Tumori, in Milan. "The addition of Herceptin to neoadjuvant chemotherapy shows extremely positive benefits for patients."

The NeOAdjuvant Herceptin (NOAH) study for patients with HER2-positive locally advanced breast cancer randomized 228 patients with centrally confirmed HER2-positive disease to standard preoperative chemotherapy plus trastuzumab for one year or to preoperative chemotherapy alone. In parallel, 99 patients with HER2-negative breast cancer were treated with chemotherapy alone.

Researchers found that trastuzumab plus chemotherapy completely eradicated tumor (pathological complete response rate) in nearly twice as many patients (43 percent) as chemotherapy alone (23 percent) and had a total pathological complete response rate (including disappearance of disease in lymph nodes) of 38 percent versus 20 percent. Treatment was well tolerated with acceptable cardiac safety.

The trial is ongoing and event-free survival data are maturing.