Studies on OPSPA. III. Distribution and excretion of radioactivity following administration of OPSPA-C14 and OPSPA-P32 to humans.

Following the recognition that N-ethylene-substituted phosphoramides possess tumor-inhibitory properties against transplanted tumors in animals (cf. 8), there have been a number of clinical studies reported in the literature (1-6, 11-13). These have usually dealt with the action of TEPA and thioTEPA primarily against leukemias. OPSPA itself has undergone extensive clinical evaluation against solid tumors in the University Hospitals (4,5), and a detailed clinical report will be given elsewhere. In none of these studies has any information on the excretion, distribution, and metabolism of the drugs in man been obtained. In the case of OPSPA, a compound that causes complete regression of es tablished Flexner-Jobling carcinomas with a single, nontoxic dose (8), such studies in human cancer patients have been carried out concurrently with these in tumor-bearing rats (9). The present paper reports the results of studies on the distribution, excretion, and blood levels of radioactivity follow ing administration of OPSPA-C14 and -PM to human patients by several routes.