Randomized clinical trials for hematopoietic stem cell transplantation: lessons to be learned from the European experience.

We evaluated the number and characteristics of randomized controlled trials (RCTs) addressing hematopoietic stem cell transplantation (HSCT) for patients with hematological malignancies, comparing the productivity of US and Europe. A MEDLINE search was conducted to identify all published RCTs for the management of adult patients with hematological malignancies from January 1992 to December 2003. Eighty-three of the 306 trials identified included HSCT as one of the treatment arms. The US produced 25, Europe 54, and all other countries four. Four European countries, France, Italy, Germany, and UK (FIGU), produced 32 out of the 54 European studies. Significant differences emerged when focus of the study and accrual numbers were analyzed. Trials comparing HSCT to standard dose therapy represented 34.9% of the 83 trials and 59.4% of FIGU trials, but only 4% of US studies (P = 0.001). US trials accrued a mean of 110.2 patients per study, as compared to 222.6 in FIGU studies (P = 0.006) and 205.3 when all non-US countries are considered (P = 0.01). Our conclusions are that US transplant RCT have focused on issues other than the comparison of HSCT to standard therapies. There is serious paucity of US trials defining the role of HSCT in the management of hematological malignancies.