Researchers to present results from breast cancer trials

"NeoALTTO is a randomized, phase III clinical trial evaluating whether a combination of two HER2-targeted therapies, trastuzumab and lapatinib, given with standard paclitaxel chemotherapy before surgery [neoadjuvant therapy] is better than just one of the HER2-targeted therapies given with the same chemotherapy," said Martine Piccart-Gebhart, M.D., Ph.D., chair of the Breast International Group (BIG) in Brussels, Belgium. "We previously reported that the combination therapy resulted in more patients having a pathologic complete response.

"In San Antonio, we will present our analysis of whether improved pathologic complete response rates translate into better long-term outcomes for patients," continued Piccart-Gebhart. "I believe that our results will be vital for the process of drug development in the field of early HER2-positive breast cancer."

Neoadjuvant therapy is treatment given to shrink or eliminate a tumor before surgery. In some patients with breast cancer, neoadjuvant therapy effectively eliminates the tumor, and no invasive cancer is detectable in breast tissue and lymph nodes removed during surgery. These patients are said to have had a pathologic complete response.

In 2014, the results of NeoALTTO's "sister" trial, Adjuvant Lapatinib and/or Trastuzumab Treatment Optimization (ALTTO), which is testing the effectiveness of dual treatment with trastuzumab and lapatinib after breast cancer surgery, will also become available, according to Piccart-Gebhart. "If the results of both studies are in line with each other, and depending on the strength of the results, we could witness a new standard of care for managing primary HER2-positive breast cancer," she said.

From January 2008 to May 2010, Piccart-Gebhart and colleagues enrolled in the NeoALTTO study 455 patients with HER2-positive primary breast cancer with tumors greater than 2 cm in diameter. Of those patients, 154 were randomly assigned to lapatinib, 149 to trastuzumab, and 152 to the combination. These HER2-targeted therapies were given alone for six weeks and then the chemotherapy paclitaxel was also administered for a further 12 weeks, at which point surgery was conducted. After surgery, patients received adjuvant chemotherapy followed by the same HER2-targeted therapy as in the neoadjuvant phase to complete 52 weeks. Follow-up is planned for 10 years after the last patient was randomized.

The researchers have previously reported that 51.3 percent of patients randomly assigned to neoadjuvant trastuzumab plus lapatinib had a pathologic complete response compared with 29.5 percent and 24.7 percent of patients randomly assigned to neoadjuvant trastuzumab and neoadjuvant lapatinib, respectively.