THREE PHASE I TRIALS of the radio protector S-2-(s-aminopropylamino) ethlyphosphorothioic acid (WR2721) have accessed 60 patients. Study 1 is devised to determine the maximum tolerated dose (MTD) of a single dose of the protector 15 to 30 minutes before a single radiation treatment of a size used routinely in paliative management. Study 2 plans to determine the MTD for up to 15 daily doses of the drug over 3 weeks during palliative radiotherapy. Also, the multiple-dose study will establish the MTD before palliative irradiation for fewer than five fractions a week. Study 3 uses the existing single-dose MTD determined in Study I as treatment 15 to 30 minutes before cyclophosphamide cis-platimum. Toxic symptoms include emesis, hypoension, hypetension, somnolence, and sneezing. Only the serious episode of hypo tension, considered idiosyntrabc, and one instance of moderate to severe vomiting five occurred. Forty-one patients have been entered in study 1 and dose of 600 mg/m2 has been reached. The step is to proceed to the planed highest level of 740 kg/m2. Of five patients in the multiple-dose study, one been given without toxicity, WR2721 at the level of mg/m2 for 15 fractions over 3 weeks. Fourteen patients are accessed to the alkyl ting agent study. Using doses of 450 mg/m2, a cyclophosphamide level 500 mg/m2 has been accomplished. However, two three patients who received 450mg/m2 of WR2721 120 mg/m2 of cis-platinum have shown moderateof the serum cretonne, both of which returned normal.
a Department of Radiation Therapy, Hospital of the University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania.
b Department of Medicine, Hospital of the University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania.
c Department of Biomedical Physics, Cancer Research and Treatment Center, University of New Mexico, Albuquerque, New Mexico.