Herceptin plus lapatinib shows “amazing” potential in breast cancer

by Bruce Sylvester: Researchers report that Herceptin (trastuzamab) plus lapatinib can shrink breast cancer tumors in less than two weeks. The findings were reported in March at the European Breast Cancer Conference in Amsterdam.

Prof Nigel Bundred, from the University of Manchester (UK) and the University Hospital of South Manchester NHS foundation trust, who presented the data, said, “This has groundbreaking potential because it allows us to identify a group of patients who, within 11 days, have had their tumours disappear with anti-HER2 therapy alone and who potentially may not require subsequent chemotherapy.

The investigators enrolled 257 women with HER2 positive breast cancer who were in the brief period between diagnosis and surgery to remove their tumors.
Initially the subjects were randomized to receive either trastuzamab or lapatinib or no treatment. But halfway through the trial, after evidence emerged from other trials of the effectiveness of the trastuzamab/lapatinib combination, the investigators changed the study design so that additional women allocated to the lapatinib group were also prescribed trastuzumab.
They reported that among the women receiving combination therapy, 17% had minimal residual disease (invasive tumor smaller than 5mm in size) and 11% had no biological sign of an invasive breast tumor. Of the women treated with trastuzumab monotherapy, only 3% had minimal residual disease or complete response.

Samia al Qadhi , chief executive at Breast Cancer Care (UK), said, “For some HER2 positive breast cancer patients the effect of this drug combination will be amazing and mean they can avoid chemotherapy and its grueling side effects completely. For others, their tumours may not shrink, but doctors will know either way very quickly, giving them the ability to rapidly decide on further treatment. Although an early study, this has game changing potential. Yet before this can be made available we need to see more evidence. Particularly because, at present, trastuzumab’s (Herceptin) licensing means it is only available to be used alongside chemotherapy and not alone.”