• OX401 is the second candidate utilizing Onxeo’s proprietary platform of decoy agonists, platON™
  • OX401 is optimized to be a next-generation PARP inhibitor, designed to act on both the DNA Damage Response and the activation of immune response
  • In vivo proof-of-concept results alone and in combination with cancer immunotherapies are expected by early Q4 2019

Paris (France), June 20, 2019 – 6:30 pm CEST – Onxeo S.A. (Euronext Paris, NASDAQ Copenhagen: ONXEO), (“Onxeo” or “the Company”), a clinical-stage biotechnology company specializing in the development of innovative drugs targeting tumor DNA Damage Response (DDR) in oncology, in particular against rare or resistant cancers, today announced that its new optimized drug candidate, OX401, has started its proof-of-concept  preclinical phase. Results of these studies are expected by early Q4 2019.

OX401 was designed by capitalizing on Onxeo’s expertise of oligonucleotides acting as decoy agonists and exhibits very original properties. During optimization, OX401 has demonstrated that it inhibited the DNA Damage Response by acting on PARP proteins. In parallel, OX401 activated the STING pathway, a recent and promising field of research in immuno-oncology, which makes it amenable to combinations with immuno- oncology agents such as checkpoint inhibitors.

A comprehensive patent has been filed for OX401 to protect Onxeo’s intellectual property rights on this product, alone and in combination with cancer immunotherapies, until 2039.

Françoise BONO, scientific director, commented: “This new development program represents a significant milestone for Onxeo, as it expands our R&D pipeline and prominently positions the Company at the crossroads of two of the most active fields in oncology, DNA damage response and cancer immunotherapy. Based on the experience and insights gained during the development of AsiDNA™, our first-in-class DNA repair inhibitor, we have developed and optimized OX401 to maintain its unique mechanism of action, while targeting other DNA-binding proteins and other mechanisms of tumor growth, such as the immune response. OX401 could represent a new generation of PARP inhibitors that do not have the limitations of current products, such as the induction of resistance, while providing improved biological properties, especially the activation of innate immunity within tumors.”

While the clinical relevance of PARP inhibitors is now well-established, this class still has a number of limiting factors, particularly the relatively rapid onset of resistance. Its decoy agonist mechanism of action positions OX401 as a next-generation PARP inhibitor that should not present these limitations and instead offer a lack of acquired resistance and more specificity to cancer cells.

OX401 was also developed to induce a strong immune response through the activation of the STING pathway, an area of significant interest in immuno-oncology. However, current molecules have experienced challenges, notably in terms of toxicity. OX401 is based on the same decoy agonist mechanism as AsiDNA ™, Onxeo’s first-in-class DNA repair inhibitor, which showed good tolerance in the DRIIV-1 Phase 1 study, and should trigger a rapid and significant inducing effect of innate immunity against tumor cells.

Preclinical proof-of-concept results showing OX401 efficacy, alone and in combination with immunotherapy treatments, are expected early Q4 2019.