IO101 is a peptide vaccine encompassing an HLA-A2-restricted, 9 amino acid IDO-derived CD8+ T-cell epitope. IO101 is currently in phase II clinical trial.

A first-in-man clinical phase I vaccination trial using IO101 was conducted. The study comprised 15 HLA-A2+ patients with advanced NSCLC who were vaccinated with IO101 in Montanide adjuvant following pre-treatment with topical Imiquimod (Aldara® Cream). The vaccine was well tolerated with manageable side effects and no CTCAE grade 3/4 toxicities.

One patient obtained an objective partial response after demonstrating continuous regression of liver metastases on vaccine treatment for 1 year.

Presently a small phase II study is ongoing in melanoma patients. In this study, IO101 together with an A2 Survivin peptide is used for vaccination in combination with temozolomide chemotherapy treatment.

More information can be found in this recent publication: Long-lasting disease stabilization in the absence of toxicity in metastatic lung cancer patients vaccinated with an epitope derived from indoleamine 2,3 dioxygenase