The purpose of this study is to test the effect of thalidomide in patients with multiple myeloma. The patients receive either thalidomide or a placebo tablet (neither patient nor doctor know which of these are given) in addition to the ordinary chemotherapeutic drug against multiple myeloma. We will find out for how long time the patients will stay free of the disease and for how long time they will live, and can evaluate whether thalidomide is a beneficial drug against this disease.