Relevance of clinical trials in acute myeloid leukaemia

Patients with newly diagnosed acute myeloid leukaemia (AML) are increasingly being enrolled in clinical trials sponsored by pharmaceutical companies or the National Cancer Institute. These trials routinely exclude patients who are less likely to respond (LLTR), e.g. those with Zubrod performance status >2 and levels of bilirubin or creatinine >2.0 mg/dL. Here we examine rates of enrollment of LLTR patients in clinical trials over the past 16 years. Overall, 2323 adults with newly diagnosed AML (excluding acute promyelocytic leukaemia) were registered on clinical trials from 1991 to 2006. LLTR patients constituted a significantly smaller proportion of the patients enrolled from 1999 to 2006 than from 1991 to 1998 (p < 0.0001, considering all patients and patients 60 years or older). While 54% of patients considered 'more likely to respond' (MLTR) (i.e. those with performance status <3, bilirubin <2.0 mg/dL and creatinine <2.0 mg/dL) were enrolled in these studies from 1999 to 2006, only 36% of LLTR patients were enrolled during this period (p < 0.0001). Our results suggest that newer clinical trials may be less applicable to LLTR patients than previous trials. There is a need for clinical trials specific to the LLTR population the group most in need of novel therapies.