An experimental drug helped mice recover faster after a brain haemorrhage, limiting the damage that follows the initial bleed without making the bleeding worse.
BIOX-101 accelerated recovery and reduced secondary brain injury after brain haemorrhage in mice without increasing bleeding, preclinical research found.
The experimental treatment reduced inflammation and nerve cell damage following intracerebral haemorrhage (ICH), a type of stroke caused by bleeding within the brain.
The improvements were associated with reduced infiltration of neutrophils, immune cells that can contribute to further brain injury after the initial bleeding.
Belgian biopharmaceutical company Bioxodes reported the findings from research conducted with ETAP-Lab and professor Denis Vivien of Caen University Hospital in France.
Stéphanie Demoulin, corresponding author of the study and medical writer and intellectual property manager at Bioxodes, said: “Our findings show that BIOX-101 reduced neutrophil infiltration and the formation of neutrophil extracellular traps and this was associated with less neuronal damage.
“Furthermore, and most importantly, these effects were combined with faster functional recovery.”
The study investigated whether BIOX-101 could limit secondary brain injury caused by inflammation in the days following a haemorrhage.
Neutrophils contribute to this process partly by releasing neutrophil extracellular traps (NETs), structures that can promote harmful inflammation.
BIOX-101 is being developed to target inflammatory processes involved in this damage.
Researchers tested the treatment in mice with experimentally induced brain haemorrhages.
The animals received an initial intravenous injection of BIOX-101 followed by a 69-hour infusion, beginning immediately after the haemorrhage was induced.
The study compared treated mice with those given an inactive solution or enoxaparin, an anticoagulant medication that reduces blood clotting.
Inflammation, nerve cell damage and brain lesions were assessed during the first three days, with safety and functional recovery monitored until day 14.
BIOX-101 significantly improved neurological and movement recovery compared with the control treatment.
By day five, treated mice had a neurological impairment score of 1.55, compared with 2.21 in the control group.
A corner test measuring movement asymmetry also showed better results, at 69.5 per cent among treated animals compared with 83.5 per cent in controls.
By day 14, mice receiving BIOX-101 had returned to baseline performance on the corner test, while untreated animals remained impaired.
The improvement continued after the three-day infusion ended.
Brain tissue analysis showed significantly fewer neutrophils entering the injured area by day three, alongside fewer cells releasing extracellular traps at the haemorrhage site.
Enoxaparin did not produce a statistically significant reduction in either measure.
BIOX-101 also reduced the proportion of degenerating neurons, or damaged nerve cells, at the bleeding site and in another region examined by the researchers.
The treatment did not increase bleeding or brain lesion size.
MRI scans showed no differences in haemorrhage or lesion volumes between BIOX-101 and the control treatment on days one, three, five or 14.
Enoxaparin was associated with a greater haemorrhage volume than BIOX-101 on day one.
Separate laboratory experiments using neutrophils from three healthy human donors found that BIOX-101 associated with more than 98 per cent of these cells.
Researchers said this supported the possibility that the treatment acts directly on neutrophils involved in secondary brain injury.
The preclinical findings follow results from Bioxodes’ Phase 2a BIRCH trial in patients with intracerebral haemorrhage, presented at the World Stroke Congress on 21 October 2026.
That clinical study found BIOX-101 was well tolerated, with no increase in bleeding.
Compared with standard care, patients receiving the treatment had statistically significantly lower haematoma expansion and growth of perihaematomal oedema at 72 hours.
A haematoma is a collection of blood, while perihaematomal oedema refers to swelling in the brain tissue surrounding the bleeding.
Inflammatory biomarkers, which indicate inflammation in the body, also showed a more favourable pattern among treated patients.
Although the animal findings are consistent with the clinical results, the improvements in functional recovery observed in mice have not been established in people.
Bioxodes is now preparing BIRCH 2, a proposed international Phase 2b trial involving approximately 230 patients with intracerebral haemorrhage.
The randomised, double-blind, placebo-controlled study will compare BIOX-101 with an inactive treatment, with neither participants nor investigators knowing which treatment has been assigned.
Its primary outcome will be the volume of swelling around the haemorrhage at 72 hours, adjusted for measurements taken at the start of the study.
Researchers also plan to assess functional recovery at 90 and 180 days using the modified Rankin Scale, which measures disability following stroke.
Deaths from any cause will be another secondary outcome.
The trial is expected to use the same patient selection criteria and treatment regimen as the earlier BIRCH study, following recommendations from an independent data monitoring committee and clinical experts.
BIOX-101 has received orphan drug designation from the US Food and Drug Administration and the European Medicines Agency.
Bioxodes said the data package for the proposed Phase 2b trial is complete and that it is in discussions with potential partners and investors to finance the study.
The next trial will assess whether BIOX-101 can reduce swelling following intracerebral haemorrhage, while also examining patients’ longer-term functional outcomes.
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