-Phase 2 Combination Study Demonstrates Decreases in T Regulatory Cells and Expansion of CD28+ Memory Cytotoxic T Lymphocytes (CTLs)-

–Data Presented at 2011 ASCO Annual Meeting–

Durham, NC– June 1, 2011 — Argos Therapeutics announced today that its ArcelisTM immunotherapy for the treatment of renal cell carcinoma (RCC), AGS-003, in combination with sunitinib demonstrated a strong immunologic response that correlated to improved clinical outcomes. The Phase 2 combination study in newly diagnosed, metastatic RCC patients with unfavorable prognosis demonstrated decreases in T regulatory cells, along with a concurrent expansion of CD28+ memory cytotoxic T lymphocytes (CTL). Results will be presented by Dr. Robert Figlin, director of the Division of Hematology/Oncology at the Cedars-Sinai Samuel Oschin Comprehensive Cancer Institute, in a poster and a discussion session at 8 a.m. CDT, and noon CDT, respectively, Saturday, June 4, 2011, at the 2011 Annual Meeting of the American Society of Clinical Oncology (ASCO) in Chicago.

The study is the first to demonstrate the combined immunologic and clinical effects of AGS-003, or any active immunotherapy, with sunitinib. Most patients experienced reversal of baseline tumor-induced immunosuppression and showed improved progression-free survival (PFS) compared to the expected PFS with sunitinib alone in an unfavorable risk, metastatic RCC patient population. Assessment of immunodynamics using multiparametric flow cytometry was performed on peripheral blood mononuclear cells isolated from blood draws collected prior to treatment and after treatment with AGS-003 during combination administration with sunitinib. Nine of 11 patients with PFS of >10 months demonstrated CTL population increases whereas two of four patients with PFS <10 months showed increases in this specific CTL population. Updates on the correlation between prolonged PFS and CTL expansion will be presented during ASCO. “The study provides initial evidence that AGS-003 works as designed to address the underlying immune suppression observed in metastatic RCC patients, while also generating a highly specific and durable T-cell response that appears to improve clinical outcomes in terms of PFS, when combined with sunitinib,” said Charles Nicolette, Ph.D., chief scientific officer and vice president of research and development of Argos. “This is the first prospective analysis of immunodynamics in RCC patients receiving sunitinib in combination with an immunotherapy, and we plan to confirm these positive results in a randomized setting in a Phase 3 clinical trial.”