[The planning of therapeutic trials in leukemias].

The planning of therapeutic trials in leukemias presents special problems due to the very variable spontaneous courses. The chronic forms are better accessible to an individual comparison. With the multitude of objective criteria relatively few difficulties arise if long enough periods of therapy are planned and performed. The criteria for the composition of homogeneous collectives as the basis for the much more difficult group comparison are discussed. In the absence of a subdivision into stages the duration of the past history can be used as a substitute criterion. Non-homogeneity in this regard leads to erroneous results, a practical example for which is given. Important is also the consideration of therapeutic and non-therapeutic contributory causes to be regarded already in the planning. The documentation of the findings should be made on special form sheets, a personal model of which is brought up for discussion. Finally the cooperation of several clinics in the therapeutic sector is discussed and the special problems of such a procedure outlined.