- Post-hoc analysis shows a substantial reduction in ALSFRS-R decline rate versus placebo at week 6, sustained at the month 4 follow-up
- Target engagement confirmed by significant reduction in plasma claudin-5, supporting restoration of the blood-brain barrier
- Good safety and tolerability profile in ALS patients
- Detailed presentation of results will be given on November 15, 2026, at Neuroscience 2026, the annual meeting of the Society for Neuroscience
- Results support continuation of NX210c clinical development.
Credit: Axoltis Pharma
NX210c
Axoltis Pharma, a biotech company dedicated to developing novel therapeutic solutions for neurodegenerative diseases, today announces the topline results of SEALS, its Phase 2 clinical trial evaluating the effect of NX210c in patients with Amyotrophic Lateral Sclerosis (ALS). This drug candidate has three properties relevant for treating neurodegenerative diseases: blood-brain barrier (BBB) restoration, neuroprotection, and enhancement of neurotransmission.
Between October 2024 and October 2025, 82 ALS patients spread across 16 French clinical sites were enrolled in the SEALS study. Patients were stratified by low and high serum neurofilament light chain (NfL) concentration and randomized (3:3:2) in three arms to receive NX210c at either one of two dose levels (5 mg/kg or 10 mg/kg) or placebo, administered as 10‑minute intravenous infusions 3 times weekly for 4 weeks.
While NX210c did not meet the primary endpoint of change from baseline to week-6 in NfL or albumin quotient between cerebrospinal fluid and blood (Qalb), consistent positive trends were observed in secondary and exploratory assessed parameters.
In post-hoc analyses, the decline rate of clinical function, assessed by the Harmonized Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) slope, was substantially reduced versus placebo (-0.67 point/month for 5mg/kg arm, -0.9 for 10mg/kg and -1.14 for placebo, corresponding to an average reduction of 41% for 5mg/kg and 21% for 10mg/kg) at week 6. This effect was consistently stronger at week 10 (-0.77 point/month for 5mg/kg arm, -1.06 for 10mg/kg and -1.57 for placebo corresponding to an average reduction of 51% for 5mg/kg with p<0.05 and 32% for 10mg/kg). The effect on the decline rate was also maintained at month 4 (-1.01 point/month for 5mg/kg arm, -1.08 for 10mg/kg and -1.59 for placebo corresponding to an average reduction of 36% for 5mg/kg and 32% for 10mg/kg).
Benefits were especially observed in the motor function subscale, with an average reduction of about 64% for 5mg/kg, p<0.05, and 33% for 10mg/kg for weeks 6 and 10, and still observable at month 4 with an average reduction of 42% for 5mg/kg and 18% for 10mg/kg. The decline of the respiratory subscale was also substantially attenuated at week 10, with an average reduction of 59% for 5mg/kg and 91% for 10mg/kg with p=0.066, and at month 4 with an average reduction of 53% for 5mg/kg and 84% for 10mg/kg with p<0.05.
At week 6, a trend toward dose-response in serum NfL was observed, which was even more pronounced at month 4. In that same month, 25.4% of the patients in the active dose arms had a decrease in serum NfL of more than 10% from predose, while only 11.8% of the patients in the placebo arm did.
The percentage change from predose of plasma claudin-5, a resident tight-junction protein mainly expressed in the endothelial cells of the neurovascular unit that acts as a gatekeeper of the BBB, was significantly reduced (p<0.001) at 10mg/kg vs the placebo arm at the end of treatment, with a dose-effect relationship. This effect was maintained at month 4 (p=0.069 for 10mg/kg arm). Claudin-5 is released into the bloodstream in case of BBB dysfunction. Therefore, observing a decrease in its circulating levels serves as a promising proxy for barrier recovery.
The SEALS trial confirmed the good safety and tolerability profile of NX210c in ALS patients with no drug accumulation, and pharmacological parameters have already been observed in Phase 1.
“These results are promising and contribute to generating evidence that NX210c’s properties are beneficial in neurodegenerative diseases, especially ALS. These findings support advancing NX210c to the next stages of clinical development. We are very grateful to all the patients participating in the SEALS study, their caregivers, the investigators and their team, the service providers and our team,” said Dr. Annette Janus, neurologist and chief medical officer at Axoltis Pharma.
“The observed effect of NX210c in reducing plasma claudin-5 opens new avenues for the use of NX210c to treat a broad range of indications where blood-brain barrier dysfunction is observed, among them Alzheimer’s disease, Parkinson’s disease and multiple sclerosis,” said Yann Godfrin, CEO at Axoltis.
Axoltis is exploring the next clinical steps for NX210c in ALS. Additional analyses are underway, including a 10-month follow-up of the patients and the PKPD relationship, to determine the potential optimal regimen of treatment repetition able to sustain the clinical effects.
The results will be presented in more detail during Neuroscience 2026, the annual meeting of the Society for Neuroscience, in Washington, DC (USA) on November 14 -18. “These results represent an important milestone for Axoltis and provide a strong foundation for the next stages of clinical development,” said Dr. Gilles Avenard, chairman of Axoltis’ board. “We will engage with the regulatory health authorities to define a clear and streamlined development pathway and to determine the most appropriate next steps.”
“The execution of the SEALS clinical study has been a success thanks to the FILSLAN (Filière de Santé Maladies Rares SLA et Maladies du Neurone Moteur) and ACT4ALS/MND networks, the invaluable support of ARSLA, Les Invincibles, the Swiss ALS Foundation, the Auvergne-Rhône-Alpes Region and Bpifrance, as well as the backing of Axoltis’ investors. We are deeply grateful to them all,” added Dr. Godfrin.