Although chemotherapy kills cancer cells, it also kills normal blood cells. As a result chemotherapy can only be given every 3 weeks, as it takes this long for the normal blood cells to recover. However, the cancer cells may also grow in the 3 weeks between chemotherapy cycles. Researchers thought that a drug called G-CSF might help the normal blood cells to recover more quickly, and so enable people to have chemotherapy every 2 weeks. So they designed a trial to see if this was the case. Two drug companies made G-CSF. The LU15 trial looked at the G-CSF made by one company (Amgen) and LU14
looked at the G-CSF made by another company.