SAMARIUM-153-EDTMP IN BONE METASTASES OF HORMONE-REFRACTORY PROSTATE CARCINOMA - A PHASE-I II TRIAL/

Samarium-153-ethylenediaminetetramethylene phosphonic acid (EDTMP), a bone-seeking radiopharmaceutical, was given to prostate cancer patient s in a dose escalation protocol for pain palliation to determine the m aximally tolerated dose. Fifty-two patients with hormone refractory pr ostate cancer with bony metastases were treated with doses beginning a t 0.5 mCi/kg (18.5 MBq/kg), escalating in 0.5-mCi (18.5 MBc) increment s to 3.0 mCi/kg (111 MBq/kg). Pain response after treatment was assess ed as well as hematologic and serum chemistry parameters. Pain palliat ion with a mean duration of 2.6 mo was present in 74% of the patients. Toxicity was exclusively hematologic at the highest dose levels. No i nfectious or bleeding complications occurred, with 45 of the 52 (86%) patients demonstrating complete hematologic recovery. Patients receivi ng higher doses had significantly greater reductions in serum prostate specific antigen and serum prostatic acid phosphatase levels. The pat ients receiving greater doses also showed a trend toward improved surv ival.