Xenothera, the EIC Accelerator and the Promise of COVID Antibodies

In the first weeks of the pandemic, a small Nantes biotech offered something the big drug makers could not yet supply: antibodies against SARS-CoV-2 taken from pigs and stripped of the animal sugar antigens that trigger immune reactions in people. Xenothera called its candidate XAV-19. In the EIC Accelerator pilot's March 2020 cut-off, the European Commission selected the project, BRIGHT, for a grant, and the EU contributed €2,162,650 towards a total cost of €3,127,625, according to CORDIS. The goal was a double-blind trial showing that XAV-19 helped patients in hospital recover quickly.

The trial happened. It did not prove the drug worked. Xenothera's international study was "interrupted in November 2022" because of "insufficient enrollment", and its interim results were "not statistically significant therefore preventing the company from demonstrating the clinical benefit of XAV19", the company wrote in its final report on CORDIS. The trial registry gives the same reason, "Lack of recruitment", in the ClinicalTrials.gov record. Today Xenothera is still active, but its pipeline is led by cancer and transplant antibodies.

Where Xenothera Stands Now

Xenothera is an active company. The French company register lists it as an active SAS with Odile Duvaux as president and Ernst & Young Audit as statutory auditor, according to the government company search, and it raised its share capital again in August 2026, to €206,666, according to the BODACC, the official gazette of company notices. North Data shows the same capital history and no insolvency filing; neither does the BODACC.

What has changed is the product. The company's pipeline page now leads with XON7, an antibody against solid tumours "in clinic since 2023", and LIS22 for peripheral T-cell lymphoma, followed by the transplant drug LIS1. XAV-19 is still listed, but without a development stage. In October 2025 Xenothera described "three of its products" in clinical trials and its "position in oncology", according to its own release. When it published the XAV-19 results in 2024, Duvaux said the company had "no plans to return to the battlefield" of COVID-19, according to the company. By the standard used in this series, that is a pivot: the lead products today are not the technology the EIC funded, even though they come from the same antibody platform.

The Technology: Polyclonal Antibodies From Edited Pigs

The established passive treatments for COVID-19 were convalescent plasma and monoclonal antibodies, single antibodies that bind one spot on the virus. Both "have demonstrated efficacy but also limitations, such as variant resistance and high cost", Xenothera argued in its CORDIS report. Polyclonal antibodies, the mix an immunised animal produces, bind the virus in several places at once. The catch with animal antibodies is that the human immune system can react to their foreign sugar antigens.

Xenothera's platform tackles that problem with what it calls glyco-humanised polyclonal antibodies. XAV-19 is "a swine glyco-humanized polyclonal antibody" against the receptor-binding domain of SARS-CoV-2, and "thanks to the removal of xeno-antigens" it "is likely to prevent post-infusion serum sickness and allergies", the trial investigators wrote in Frontiers in Immunology. The French health technology agency describes the active substance as porcine immunoglobulin G in its January 2022 decision. The animals live on a company farm with what Xenothera says are 500 animals, a facility it calls unique in Europe, according to a company note on a Les Échos report. That claim could not be checked independently.

What BRIGHT Promised, and What the Record Shows

The European Commission's list of selected companies names XENOTHERA of Nantes as the only beneficiary of BRIGHT, with "Grant only" as the type of finance. CORDIS classes the project under the Horizon 2020 SME instrument call and dates the grant agreement 27 July 2020. The objective was to prepare XAV-19 and run "a phase 2 double-blind clinical trial of XAV19 versus placebo", with "the quick recovery of patients admitted at the hospital" as the endpoint.

Most of the groundwork was done. The final report lists hyperimmune sera, purification to good manufacturing practice, toxicology and preclinical safety studies, clinical trial authorisation "in 6 different countries" and 287 patients recruited into a trial called EUROXAV. The sources disagree on the numbers: the registry record lists five countries (Bulgaria, Greece, Romania, Spain and Turkey) and 290 enrolled, and the published paper reports 279 randomised patients. The trial ran from 28 April 2021 to 28 November 2022, within the project's 29 months.

The trial missed its primary endpoint, the share of patients whose disease got worse within eight days. That happened to 8.5% of patients on XAV-19 and 6.9% on placebo, and the authors write that "underpowered statistics did not allow the detection of any difference in the primary endpoint between the two groups", according to the paper. A slow enrolment and fewer events than expected led the data and safety monitoring board to recommend stopping. Five of the authors were Xenothera employees, the paper discloses.

The positive result came from a secondary measure. Patients with milder disease, WHO scores of 2 or 3, improved in a median of 7 days on XAV-19 against 14 on placebo (p = 0.0159). Xenothera's 2024 press release presented this as the drug's "clinical efficacy" and did not mention that the primary endpoint was missed.

1. GMP batches and preclinical safetyDeliveredListed as done in the CORDIS report; the product reached patients in two registered trials.
2. Double-blind placebo-controlled trialRunEUROXAV, phase 2/3, 279 randomised, results published in 2024.
3. Full recruitmentNot achievedTerminated for "lack of recruitment" in November 2022.
4. Clinical proof of conceptNot achievedPrimary endpoint missed; the company's own report says benefit was not demonstrated.
5. Faster recovery in hospitalSubgroup onlySignificant for WHO scores 2 or 3, a secondary analysis.
6. Route to patientsNot achievedFrench early access refused in January 2022; no marketing authorisation announced since.

The French Bet on XAV-19

Before the EU trial reported, France had already backed the drug. In May 2021 the government reserved 30,000 doses of XAV-19, which it would pay for only if the treatment was authorised, The Connexion reported. Duvaux told Maddyness the same year that the pre-reservation covered three to four months of French use, and that the company planned capacity for 200,000 doses in 2022 and 600,000 a year from 2023.

A first French phase 2 trial, POLYCOR, was sponsored by Nantes University Hospital with Xenothera and Bpifrance as collaborators and enrolled 416 patients in France, Martinique and Réunion, according to its registry record. Xenothera applied for early access on 30 September 2021. On 27 January 2022 the Haute Autorité de santé refused, citing an opinion of the medicines agency ANSM that the drug's efficacy and safety "n'étaient pas fortement présumées" (were not strongly presumed), according to the HAS decision. Le Quotidien du Pharmacien reported the refusal for lack of "intérêt thérapeutique prouvé à ce stade". The decision notes that Xenothera had committed to apply for a marketing authorisation; no such authorisation has been announced.

What Xenothera Has Achieved Since the Award

The money arrived even as the drug stalled. In 2021 Xenothera closed a €20 million round led mainly by the EIC Fund and the holding company Nabuboto, with Anaxago Capital and Malakoff Humanis, according to Le Monde du Droit, which reported Linklaters' advice to the EIC Fund. Duvaux also put the round at €20 million in Maddyness. The CORDIS report gives €21 million of equity raised since August 2020. Xenothera appears on page 16 of the EIC Fund's list of invested companies, described with the BRIGHT project title. The EIC Fund's stake and its share of the round are not public. The investment is notable because the Commission's list shows BRIGHT itself as a grant-only award.

Later money went to cancer. In January 2025 Xenothera announced €4 million of non-dilutive France 2030 funding for the LIS22 lymphoma trial, PALT1, with the aim of early access in France and Europe by 2027, according to the company. Breizh-Info also reported €4 million for the PALT trial and €43 million raised since 2014, the same total the company gave in October 2025. Breizh-Info reported that the XON7 cancer trial had validated doses up to 12 mg. The transplant drug LIS1 holds orphan designations in the United States and Europe, the company says.

The team grew. Duvaux told Maddyness that Xenothera had 8 employees at the start of the health crisis and 17 in 2021, and the CORDIS report says it recruited 15 people during the project. The national statistics office places the company in the band of 20 to 49 employees for 2024, according to the government register search. The goal of about 40 staff by the end of 2022, given in Maddyness, could not be checked. The CORDIS report also says Xenothera filed a further patent covering XAV-19 and other antiviral antibodies in 2022 and won EY's "Start up of the year" award in 2021; no second source for the award could be found.

The Money

Xenothera files its accounts with a confidentiality declaration, so only ratios are public. The INPI figures published by the French economy ministry show zero revenue in 2022, 2023 and 2024, a net loss of €4,518,357 in 2022, a small profit of €68,909 in 2023 and a net loss of €4,956,833 in 2024, according to the ratios dataset. The 2024 figures match the government company search. What produced the 2023 profit is not public. The financial autonomy ratio, equity as a share of the balance sheet, fell from 91.0% in 2022 to 75.2% in 2024.

Why Europe Should Care

BRIGHT was exactly the kind of project the EU was asking for. On 6 May 2021 the Commission adopted a strategy for COVID-19 therapeutics that aimed to authorise three new treatments by October 2021 and to pick the five most promising from a portfolio of ten, according to Alzheimer Europe and RAPS, which reported funding of more than €140 million. A European-made polyclonal antibody, produced on a European farm and designed to resist variants, fitted that aim. It was not among the products that reached patients: EUROXAV was stopped after "a slow enrollment and a low rate of events", the investigators wrote in Frontiers in Immunology.

The platform outlived the pandemic. Xenothera now applies the same glyco-humanised antibody approach to a rare lymphoma and to organ transplantation, with France 2030 money for the lymphoma trial. Whether any of these products reaches patients is the test that XAV-19 did not pass.

The Verdict

Xenothera has not been asked for comment for this article. It is based entirely on public records, company statements and EU project data, linked throughout.