Management and treatment results in patients with acute promyelocytic leukaemia (APL) not enrolled in clinical trials.

Purpose: Acute promyelocytic leukaemia (APL) therapy with all-trans retinoic acid and chemotherapy is associated with a high cure rate in clinical trials. As some patients are not enrolled in these trials due to early severe events, these results might be overestimated. To address this issue, we reviewed all APL patients referred to the Hospital Saint-Louis within the 2000-2010 period, with a special focus on inclusion in recruiting trials.

Patients And Methods: One hundred patients (including eight children) with newly diagnosed APL were admitted during this period, which covered two consecutive APL trials conducted by the French-Belgian-Swiss APL group.

Results: The rate of patients not enrolled within recruiting trials was 29%. The main reason for non-inclusion was protocol ineligibility related to disease severity at diagnosis. Non-enrolled patients more frequently had white blood cell count (WBC) . or =50×10(9)/L (31% versus 8%; p=.01), platelet count<40×10(9)/L (97% versus 65%; p=.001) and microgranular variant APL (38% versus 11%; p=.004) and were more frequently admitted in intensive care unit during induction (41% versus 24%; p=.094). Early mortality rate was higher in non-enrolled patients (21% versus 3%; p=.007), translating into a lower complete remission rate (79% versus 96%; p=.007) and lower event-free survival (65% versus 84% at 5 years; p=.05), while disease-free survival was similar in both non-enrolled and enrolled patient groups (81% versus 88% at 5 years; p=.68).

Conclusion: Initial APL severity leads to a significant proportion of patients non-registered within clinical trials, which may underestimate the real early mortality, which remained nonetheless less than 10% in this study.