• The last patient was treated with AsiDNA™ in combination with carboplatin and paclitaxel in this Phase 1b study in patients with advanced solid tumors.
• The good safety profile of AsiDNA™ is confirmed to date, with no serious adverse events related to AsiDNA™ and no dose-limiting toxicities observed.
• Of the first seven patients, four had a partial response or longer periods of control of their disease than with previous treatment lines; three patients are still being treated.
• These preliminary data represent a particularly encouraging signal of efficacy and support further clinical development of AsiDNA™ in combination with these reference chemotherapies.

Paris (France), November 9, 2020 – 6 pm CET – 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 particular against rare or resistant cancers, today announced the completion of enrollment in the DRIIV-1b study and favorable interim results.

DRIIV-1b was designed to evaluate the safety and efficacy of AsiDNA™ in combination with carboplatin (n=3) and then carboplatin plus paclitaxel (n=6) in eligible patients with metastatic solid tumors, progressing at inclusion. The last planned patient has received treatment and will be followed until disease progression.

At this stage and on the first seven patients evaluated for safety, the favorable safety profile of AsiDNA™ in combination with carboplatine +/- paclitaxel is confirmed, as no serious adverse events related to AsiDNA™ and no dose-limiting toxicities have been observed in these patients.

In terms of efficacy, four of the seven patients experienced a partial response and/or longer durations of disease control than with previous treatment lines. Three patients are still being treated. These preliminary data represent a particularly encouraging signal of efficacy that supports further clinical development of AsiDNA™ in combination with these reference chemotherapies.

Olivier de Beaumont, Chief Medical Officer of Onxeo, said: “AsiDNA™’s mechanism of action, which prevents tumor DNA repair, is particularly well suited for combination with ‘DNA breakers’ such as chemotherapy, a reference treatment of cancer, for which clinicians seek to maximize efficacy without increasing an already significant toxicity. In DRIIV-1b, we are looking for a signal of greater efficacy than that observed with previous treatment lines, without increasing toxicity. Analysis of the first seven patients, for whom we now have sufficient hindsight, shows particularly encouraging results. For three patients with advanced metastatic cancers, sometimes heavily pre-treated, the combination of AsiDNA™ with one or two chemotherapies resulted in particularly long periods of progression-free disease control, sometimes exceeding 8 months and always longer than those obtained with previous treatment lines, including immunotherapy. One patient achieved a partial response, an outcome which was never achieved under previous treatments, including another platinum-based chemotherapy. The two last patients have started their treatment, thus completing enrollment in this study. Subject, of course, to the duration of control for three patients still being treated, we expect topline results for the entire study in early 2021, while on the basis of these positive results, we are already preparing the continuation of the clinical development of AsiDNA™ through a phase 2 study in a selected indication with high medical needs.”

About DRIIV-1b

DRIIV-1b is designed to evaluate the safety and efficacy of AsiDNA™ in combination with carboplatin (n=3) and carboplatin plus paclitaxel (n=6) in patients with advanced metastatic solid tumors progressing at inclusion. The efficacy of these combinations is evaluated every 6 to 8 weeks by medical imaging (Criteria for Evaluation of Response in Solid Tumors – RECIST). Out of the first seven evaluable patients, four patients, including three non-small cell lung cancer (NSCLC) patients, had a partial response and/or long control durations (no progression). For these four patients, the durations of control with either combination was consistently longer than those obtained with previous treatment lines, including other platinum-based chemotherapies or a first-line reference immunotherapy.