GSK stops Tykerb-only arm in cancer trial

GlaxoSmithKline ($GSK) has called a halt to one arm of its trial testing the cancer drug Tykerb against and in combination with Roche's Herceptin. GSK will stop dosing breast cancer patients with Tykerb alone after preliminary data showed subjects on this solo treatment weren't likely to do as well as those taking Herceptin only.

"The [independent data monitoring] committee has indicated that the lapatinib alone arm is unlikely to meet the pre-specified criteria to demonstrate non-inferiority to trastuzumab alone with respect to disease-free survival," GSK said in a statement.

Both drugs are used to target HER-2 positive breast cancer. GSK will continue the remaining three arms of the trial: HER-2 patients taking Herceptin (trastuzumab) alone, those taking Herceptin followed by Tykerb and those using both drugs together. Tykerb is marketed as Tyverb in Europe.

GSK mounted the so-called ALTTO trial to see whether Tykerb--alone or in combination with Herceptin--could beat Herceptin-only therapy in HER-2 cancer patients. Tykerb works against HER-2 from inside cells, while Herceptin attaches to the outside of the HER-2 protein, GSK says. Combining the two could better block HER-2, or so the theory goes. A previous GSK study showed combining Tykerb with Herceptin did benefit patients more than Tykerb alone did. More than 8,000 patients are taking part in the latest tests.

- see the GSK release
- read the Reuters news