Critical factors in new therapeutic approaches in chronic lymphocytic leukaemia (CLL)

Three critical questions in new therapeutic approaches for CLL are analyzed: balance between risks and benefits; impact of therapy on survival; and can CLL be cured? New treatments should take into account a balance between risks and benefits. Relatively risky therapies can be tried only in those subsets of patients in whom the survival is shortened as compared to the control population. The impact of new therapies on survival is best demonstrated by prospective randomized trials. Two errors are common when the response to treatment is analyzed. Frequently unsuitable statistical methods, biased in favour of responders, are employed. In addition, it is often incorrectly implied that response causes longer survival. To investigate whether CLL can be cured, more research should be directed to the characteristics of complete clonal remissions. The use of non-risky biologic response modifiers in early stages may contribute to these efforts.