XENOTHERA publishes the clinical efficacy of XAV-19, its anti-COVID antibody, in Frontiers in Immunology

XENOTHERA, a Nantes (France) – based biotech, which celebrates its tenth anniversary this year, develops innovative treatments by glyco-humanized polyclonal antibodies (GH-pAb) for infectious diseases, cancer and transplantation. Thanks to its technology, in 2020 the biotech launched XAV-19, which clinical efficacy in moderate COVID has just been published in a peer-reviewed scientific journal.

Following the demonstration of its activity against the virus (Vanhove et al. 2021, 2023), XAV-19 was tested in a phase II/III trial in patients suffering from moderate COVID (EUROXAV trial, NCT04928430, supported by the European EIC Fund and BPI France).

This new publication (Poulakou et al. Front. Immunol., 2024) demonstrates the efficacy of XAV-19 in the recovery of patients suffering from moderate COVID. 279 patients participated in the trial in five European countries. In patients with a WHO score (indicating the degree of severity of the disease) of 2 or 3, the median time to recovery fell from 14 days to 7 days (p=0.0159). The benefit of XAV-19 in patients with a WHO score of 2 was even greater, with recovery in 4 days instead of 14 (p=0.003). These results confirm the therapeutic value of XAV-19 before the severe stage, a stage where no anti-COVID antibody has demonstrated any clinical benefit.

This paper also presents the efficacy of XAV-19 against all known variants of SARS-CoV-2, confirming the value of polyclonal antibodies against a virus that is likely to develop resistant variants.

This publication confirms the value of XENOTHERA’s technology in terms of safety and clinical efficacy in viral infections, especially of XAV-19.

This paper validates our work and the therapeutic benefit of XAV-19. It has taken time, and we are happy to see any possible doubts on this treatment today dispelled. We can also confirm that XENOTHERA can produce safe and effective antibodies against an epidemic virus. Although we are in a period of resurgence for COVID, we have no plans to return to the battlefield, as we have other battles to fight, in particular in transplantation and cancer. I would like once again to thank all the patients and doctors who took part in this trial” comments Odile Duvaux, President and co-founder of XENOTHERA. “XENOTHERA’s adventure continues, for patients’ stake. The company has grown, and we have our own biomanufacturing site, which participates in health sovereignty. And if, by some misfortune, a new epidemic were to break out, we’d be even better at mobilizing quickly,” adds Odile Duvaux.

XENOTHERA’s antibodies address major therapeutic needs in several areas, including oncology, immunosuppression and severe infections. XENOTHERA’s antibody platform enables accelerated development thanks to its in-house biomanufacturing facilities, its clinical experience (over 400 patients exposed to GH-pAbs), and its clinical and regulatory expertise.

To date, four XENOTHERA’s GH-pAbs have been introduced in humans, in transplantation, Covid, infectious diseases and cancer. During the clinical trials already conducted (phase I, phase II, phase III), GH-pAbs have demonstrated their safety and therapeutic value.


About XAV-19:

XAV-19 treatment is a protective polyclonal anti-SARS-CoV-2 antibody similar to the natural human response. Based on a unique and patented proprietary polyclonal antibody technology, it acts through multiple mechanisms of action, including virus neutralization and reduced inflammation, and is active against all circulating variants. The treatment is intended for patients with moderate Covid.


Founded in 2014 by a team of renowned scientists and under the presidency of Odile Duvaux, MD PhD , a graduate of the École Normale Supérieure, XENOTHERA is a biotechnology company based in Nantes (France) that develops new therapeutic approaches in a wide range of fields, with a focus on oncology and immunology. The company is developing treatments based on a unique multi-specific glyco-human antibody technology. Its technology platform is based on dual expertise in genetics and immunology.

The biotech has a comprehensive portfolio of products, four of which have already been introduced in the clinic. Its main assets are LIS22, in onco-hematology, LIS1 in transplantation, and XON7, in solid tumors.

XENOTHERA is part of the scientific and medical environment of the Pays de la Loire region (France). Since its creation, the company has raised €43 million, its main investors being the Pays de la Loire Region, BPI France, the European EIC Fund, and private investors.

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Ingrid Zémor

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