A phase II trial to assess the activity of MVA5T4 plus interleukin-2 in patients (Pts) with metastatic renal cell carcinoma (MRCC)
14642 Background: MVA 5T4 consists of a highly attenuated vaccinia virus (modified Vaccinia Ankara, MVA) containing the human tumor associated antigen (TAA) 5T4. Greater than 90% of renal cell cancers are overexpressed by the 5T4 antigen. The primary purpose of this trial is to validate the hypothesis that, in this group of pts, it is possible to induce immune responses either humoral and/or cellular to 5T4 and to break tolerance to the antigen. The immune response will be correlated to clinical outcome. Methods: Eligibility included: pathologic diagnosis of confirmed clear cell or papillary cancer, progressive measurable MRCC, adequate organ/marrow function, Karnofsky Performance Status (KPS) ≥ 80%, any prior therapy, and no active CNS involvement. The dosage schedule of subcutaneous low dose IL-2 will be an initial dose 250,000 U/kg/dose for 5 days in week 1 followed by 125,000 U/kg/dose for 5 days each of weeks 2–6 inclusive. There will then be a 2 week recovery period before the next cycle commences. The dosage regimen of MVA 5T4 will be intramuscular injections given 14 days prior to the first cycle, day 0 and 1 injection given at the beginning of week 4 of the first cycle. In subsequent cycles, booster injections of MVA 5T4 will be given at week 1 only, prior to the commencement of subcutaneous IL-2 therapy. Results: 10 pts have been treated with MVA 5T4 and the LD IL2 regimen. The combination has been extremely well tolerated with no MVA 5T4 related events thus far. Although the study is still continuing to accrue, there are early signs of clinical responses in a number of patients receiving the combination. The immunological analysis is in progress. Conclusion: MVA 5T4 is well tolerated in this group of patients. The immune response will be presented along with clinical outcome. [Table: see text]