Phase III study compared neoadjuvant therapy with lapatinib or trastuzumab for early breast cancer

Researchers presented Phase III efficacy data from the GeparQuinto study, a head-to-head comparison of neoadjuvant lapatinib and trastuzumab in combination with chemotherapy for patients with early breast cancer, at the 33rd Annual CTRC-AACR San Antonio Breast Cancer Symposium, held Dec. 8-12.

"We had a primary goal to compare the standard anti-HER2 neoadjuvant combination of chemotherapy, trastuzumab, with the new combination of chemotherapy and lapatinib," said Michael Untch, M.D., head of the multidisciplinary breast cancer department at Helios Clinic in Berlin, Germany.

The GeparQuinto study was conducted at 85 centers throughout Germany and includes 2,500 patients, 550 of whom have HER2-neu-overexpressing breast cancer. This is the largest prospective patient cohort of chemo-targeted neoadjuvant therapy worldwide.

All patients received four cycles of 90 mg/m2 epirubicin and 600 mg/m2 cyclophosphamide every three weeks, followed by four cycles of 100 mg/m2 docetaxel. They were randomly assigned to also receive concomitant 6 mg/kg trastuzumab every three weeks or 1,250 mg lapatinib per day throughout all cycles.

At baseline, patient characteristics were similar between the two groups, with both groups presenting a clinical median tumor size of 40 mm. The researchers also reported a similar number of patients in each group with T4a-c or T4d disease, bilateral, multifocal or multicentric disease, and estrogen receptor-negative and progesterone receptor-negative disease.

The last of the patients are currently undergoing surgery, and Untch will present histological and surgical outcome results for these patients at the symposium.

"After assessing response to neoadjuvant chemo-targeted therapy in patients with HER2 overexpressing tumors, we are following the patients from this study to see whether pathologic complete response at surgery is correlated to the outcome of the patients," he said.