A combination of lapatinib, trastuzumab and paclitaxel significantly improved tumor response rates than either agent alone among patients with HER2-positive breast cancers, according to data presented at the 33rd Annual CTRC-AACR San Antonio Breast Cancer Symposium, held Dec. 8-12. Full results were presented at the symposium during a press briefing on Dec. 10, 2010, at 8:00 a.m. CT.

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Lead researcher José Baselga, M.D., Ph.D., chief of the division of hematology and oncology and associate director of the Massachusetts General Hospital Cancer Center, said early data indicate a 50 percent rate of pathological complete remission compared with 20 percent for either agent alone.

"This study suggests that a dual blockade against HER2 is an efficient way to target HER2-positive breast tumors and that lapatinib adds to trastuzumab. While further research is ongoing, our results indicate that we are on the right track to improve the therapy of HER2-positive disease," said Baselga, who is also a founding editor-in-chief of the AACR's newest journal Cancer Discovery, along with Lewis C. Cantley, Ph.D.

These results are from the NeoALTTO Trial, an international, multicenter, randomized study comparing the efficacy of lapatinib plus paclitaxel vs. trastuzumab plus paclitaxel vs. a combination of all three agents as neoadjuvant chemotherapy among 455 patients with HER2-positive breast cancer.

"It has been suggested in basic science research and smaller clinical trials that the combination of these therapies would be more effective than either alone, but this is the first time it has been shown in a large clinical trial setting," said Baselga.

At the symposium, Baselga presented the primary outcome of tumor rate after surgery, as well as the secondary outcomes of objective response rate, safety, pathologic node-negative status, rate of conversion to breast conservation, disease free survival and overall survival.