IDO: IO102

The endogenous metabolic enzyme indoleamine 2,3-dioxygenase (IDO) contributes to immune suppression by catabolizing and limiting the availability of the amino acid tryptophan, which is essential for the survival, growth and function of immune effector cells. Overproduction of IDO is a well-documented tumor escape mechanism and increased IDO levels have been detected in tumor and immune cells in several human cancers.

Our fully owned lead program IO102 is a first-in-class, second-generation immune modulatory vaccine containing a single IDO-derived peptide sequence designed to engage and activate IDO specific human anti-regulatory T-cells.

IO102 is currently being tested in two clinical trials:

  • A randomized phase I/II trial in combination with KEYTRUDA® (pembrolizumab) standard-of-care in first-line treatment of patients with metastatic Non-small Cell Lung Cancer (NCT03562871).
  • A non-randomized phase I/II trial in combination with IO103 and Opdivo® (nivolumab) in both treatment-naïve and PD-1/PD-L1 mAb refractory patients with Metastatic Melanoma (NCT03047928).


Peptide vaccination directed against IDO1-expressing immune cells elicits CD8+ and CD4+ T-cell-mediated antitumor immunity and enhanced anti-PD1 responses
Journal for Immunotherapy of Cancer, July 2020

Durable clinical responses and long-term follow-up of stage III–IV non-small-cell lung cancer (NSCLC) patients treated with IDO peptide vaccine in a phase I study - A brief research report
Frontiers in Immunology, September 2018

Safety, immune and clinical responses in metastatic melanoma patients vaccinated with a long peptide derived from indoleamine 2,3-dioxygenase in combination with ipilimumab
Cytotherapy, August 2016

Long-lasting disease stabilization in the absence of toxicity in metastatic lung cancer patients vaccinated with an epitope derived from indoleamine 2,3 dioxygenase. Clinical Cancer Research, November 2013