Why it matters: ALS remains notoriously difficult to treat, and the SEALS study did not establish an effect on its prespecified biomarkers. The more encouraging clinical findings come from post-hoc analyses, making them signals that will need confirmation in a larger trial.<\/p>\n
Zoom in: The 82-patient study randomized participants to intravenous NX210c at 5 mg\/kg or 10 mg\/kg, or placebo, three times weekly for four weeks. The trial\u2019s primary endpoint looked for changes at week six in neurofilament light chain, or NfL, and Qalb, a measure of blood-brain barrier integrity. Neither showed a significant treatment effect.<\/p>\n
Post-hoc analyses painted a more positive picture on the ALSFRS-R scale, which measures patients\u2019 ability to perform everyday functions. At week 10, monthly functional decline was 0.77 points with the 5 mg\/kg dose and 1.06 points with 10 mg\/kg, versus 1.57 points for placebo. The difference for the lower dose corresponded to a 51% reduction and reached statistical significance, according to Axoltis. At four months, the reductions versus placebo were 36% and 32%, respectively.<\/p>\n
Reality check: The stronger functional result came from the lower dose, rather than showing a clear dose-response relationship, and the analyses were not the study\u2019s primary endpoint. The trial was also relatively small and exposed patients to treatment for only four weeks.<\/p>\n
The week-six functional signal itself is not entirely new. Axoltis presented preliminary SEALS data<\/a> at the ENCALS meeting in June, including ALSFRS-R decline rates of 0.67 points per month with 5 mg\/kg, 0.9 with 10 mg\/kg and 1.14 with placebo.<\/p>\n How it works: NX210c is a synthetic 12-amino-acid peptide derived from SCO-spondin, a large protein produced in the brain that is involved in nervous system development and maintaining the integrity of the blood-brain barrier. Axoltis is developing it around three proposed effects: restoring the blood-brain barrier, protecting neurons and improving neurotransmission.<\/p>\n The company pointed to a significant reduction in plasma claudin-5 at the 10 mg\/kg dose as evidence of target engagement. Claudin-5 enters circulation when the blood-brain barrier is disrupted, so Axoltis argues that lower levels could indicate barrier restoration.<\/p>\n Big picture: ALS drug development has produced more failures than approvals. Biogen\u2019s tofersen became the first treatment aimed at a genetic cause of ALS when it won accelerated FDA approval for SOD1-ALS in 2023. Tofersen itself initially missed its primary functional endpoint<\/a> before longer follow-up strengthened the case for benefit \u2014 a reminder of how difficult short ALS trials can be to interpret.<\/p>\n