Activity of MVA 5T4 alone or in combination with either interleukin-2 (IL-2) or interferon-α (IFN) in patients (Pts) with metastatic renal cell cancer (MRCC)

3069

Background: MVA 5T4 consists of the highly attenuated modified Vaccinia Ankara virus containing the gene encoding the human TAA 5T4. Ninety percent or more of RCCs overexpress the 5T4 antigen. A series of clinical trials were conducted to evaluate the effectiveness of MVA 5T4 as a single agent or in combination with Interleukin-2 or Interferon Alpha 2B. Methods: Eligibility: pathologic diagnosis of clear cell or papillary RCC, progressive measurable metastases, any prior therapy, adequate physiologic parameters, Karnofsky performance status (KPS) = 80%, and no active CNS involvement. A regimen of MVA 5T4 alone or in combination with IFN or IL-2 was given. Results: A total of 41 patients received MVA 5T4 alone or in combination. 33 patients received MVA 5T4 with low dose IL-2 or IFN. 23 pts had clear cell; 12 papillary; 5 mixed clear cell; and 1 mixed papillary. 19 pts continue to receive therapy. 2 pts (both clear cell RCC) developed complete responses, 3 pts/partial responses (2 clear cell, 1 papillary) 8 pts/stable for 3+months and 6 pts are too early to be staged at this time. Median duration of therapy is 3.0+ (1+-13+) months. Conclusion: Although comparable antibody response were observed in papillary and clear cell histotypes, clear cell patients appeared to be more likely to respond in terms of clinical benefit parameters, to be presented. Of note is that preliminary analysis of clear cell patients suggests a relationship between the anti-5T4 immune response and tumor response. With the immunological potency and encouraging clinical activity, the future research will focus on the phase 3 randomized, double-blind, placebo controlled parallel group study to investigate whether MVA 5T4, added to first line standard of care therapy, prolongs the survival of patients with locally advanced or metastatic clear cell as well as studies to further optimize MVA 5T4 potency.

[Table: see text]