GlaxoSmithKline Plc's new breast cancer drug Tykerb is to be compared with Herceptin made by Roche in Europe.

The US National Cancer Institute announced that 8,000 patients in 50 countries will be given either Herceptin (trastuzumab) or Tykerb (lapatinib), or Herceptin followed by Tykerb, or the two drugs in combination. The trial, called ALTTO, has been developed by The Breast Cancer Intergroup of North America and the Breast International Group in Brussels (BIG), Belgium and is due to continue until 2011.

The NCI said that the study is designed “to answer the most pressing questions regarding use of two widely used cancer agents: whether one agent is more effective, which agent is safer for patients and what benefit will be derived by taking the drugs separately, in tandem order, or together?” Both Herceptin and Tykerb have been approved for treating HER2-positive breast cancer, which affects up to 25% of breast cancer patients.

ALTTO will be the first head-to-head comparison of trastuzumab and lapatinib in the earliest, most treatable stages of cancer. There are two different designs depending on whether patients with stage I or stage II breast cancer have already been treated with chemotherapy. As such, it will compare four different regimens of targeted therapy administered over a 52-week period.

Edith Perez of the Mayo Clinic in Florida, who is leading the study for TBCI, said “it may be that using two treatments that work in different ways against HER2-positive breast cancer offers a complementary strategy that is more powerful than either drug alone". Martine Piccart, of the Université Libre de Bruxelles and lead investigator for BIG, added that the difference between this study “and many that came before it is that the collection of biological materials occurs as the trial is being conducted, not as an afterthought. While there are exceptions, not many companies or organisations have been willing to invest in that kind of research before". She concluded "now we have the chance to optimise therapy with powerful drugs in order to provide the best treatment possible for each of our patients”.

Glaxo is providing financial support for the trial.