Radioimmunotherapy Phase I Dose-Escalation Studies in Prostate Cancer Using 177Lu-J591 Antibody: Dose Fractionation Regimen

Study Design: We plan to perform a phase I dose-escalation study. The trial is designed to determine the cumulative MTD in a FDR in which 177Lu-J591 will be given in 2 doses, 2 weeks apart. The dose escalation will start at 20 mCi/m2 and escalate in increments of 5 mCi/m2 to 55 mCi/m2 in up to 8 cohorts.We plan to recruit a maximum of 68 subjects in this trial.

Specific Aims: 1. Determine the cumulative MTD of 177Lu-J591 in a 2 week dose-fractionation regimen.

2. Perform imaging and pharmacokinetic (PK) studies with 177Lu-J591 in order to define the PK and dosimetry of 177Lu-J591 3. Determine the myelotoxicity of fractionated dose of 177Lu-J591 4. Monitor biochemical (PSA) and/or measurable disease response and duration.

Following the administration of 177Lu-J591 mAb on day 0, blood samples may be obtained at 10 min, 1, 2, 4 hrs, days 1, once during days 3-6, day 7 and 14. In addition, total body images may be obtained on day 0 at 1-4 hours after study treatment, day 1, once during days 3-6, days 7 and 14 using a gamma camera. (Amendment dated 15 July 2009: As investigators have gained ample information from the initial cohorts, PK and 177Lu-J591 imaging studies (other than the day 6-8 scan) will be considered optional.) Patients will be followed for a minimum of 12 weeks after the 2nd dose of 177Lu-J591 (total 14 weeks) or until toxicities resolve, disease progression or administration of alternative therapy for the patient¿s prostate cancer. Various clinical and laboratory evaluations will be performed during the first week and then every week until 12 weeks. These include, blood chemistries, CBCs, serum PSA levels, etc. If the patient¿s disease is stable or responding at 12 weeks after his last dose, he will continue to be followed until progression of disease. During the long-term follow-up, the patient¿s PSA will be monitored at least every 6 weeks and CT/bone scans will be evaluated at least every 18 weeks until disease progression.