Para-aminobenzoic acid, administered in large doses as sodium para-aminobenzoate caused a striking lowering of the leukocyte counts in five patients with chronic myelogenous leukemia and in one patient with subacute myelogenous leukemia.
NaPAB caused less definite decreases of the white cell count in two patients with chronic lymphatic leukemia, but the periods of administration may have been too short to obtain maximal effects.
In every instance, there was a prompt rise in the number of leukocytes when the administration of NaPAB was stopped.
Although there was decrease in spleen size in some of the patients, the objective clinical improvement was but slight and temporary.
All patients receiving NaPAB in large doses had concomitant glycosuria, apparently on a renal basis.
It is to be emphasized that NaPAB is not considered a practical adjunct to the therapy of leukemia at this time. Rather, it is hoped that studies of the cellular chemistry involved in the apparent inhibitory action of NaPAB may yield information concerning the disordered metabolism of leukemic cells.