23 February 2026

Phase 3 trial of experimental oral treatment recently cleared by FDA.

• Early PrimeC treatment extended ALS patient survival by more than 14 months.
• PrimeC reduced the risk of death in ALS patients by 65% versus delayed treatment.
• This oral treatment targets inflammation and iron; a Phase 3 trial is planned.

Early treatment with PrimeC, an experimental oral treatment being developed by NeuroSense Therapeutics, significantly extended survival in people with ALS by more than 14 months compared with a six-month delay in treatment initiation.

That’s according to additional long-term data from PARADIGM (NCT05357950), a completed Phase 2b clinical trial in which 68 adults with ALS received either PrimeC or a placebo for six months, and its yearlong open-label extension, in which all participants received PrimeC.

Previously reported data also showed that PrimeC significantly slowed disease progression in the main trial, with these benefits sustained in the extension part.

Results from PARADIGM served as the basis for a planned Phase 3 clinical trial called PARAGON, which has recently been cleared by the U.S. Food and Drug Administration (FDA). The company expects to begin enrolling up to 300 adults with ALS at sites in the U.S. and Europe. Patients will be randomly assigned to receive either PrimeC or a placebo for a full year. An open-label extension will follow.

“The long-term survival data further validate the magnitude and durability of PrimeC’s effect in ALS and reinforce its potential as a disease-modifying therapy,” Alon Ben-Noon, CEO of Neurosense, said. “We believe these findings substantially strengthen the clinical and regulatory foundation as we advance toward late-stage development.”

PrimeC targets inflammation, excess iron accumulation

In ALS, motor neurons — the nerve cells that control muscle movement — become gradually damaged and die, causing muscle weakness that makes everyday activities increasingly difficult. Over time, it can lead to paralysis and eventually death, usually within a few years after diagnosis.

PrimeC is an extended-release combination of two FDA-approved medications: the antibiotic ciprofloxacin and the anti-inflammatory drug celecoxib. The treatment is designed to target several mechanisms linked to ALS, including inflammation and excess iron accumulation.

In PARADIGM, patients who received PrimeC for six months experienced slower declines on the ALS Functional Rating Scale–Revised (ALSFRS-R), a standard measure of daily function in ALS, compared with those on a placebo. In patients who closely followed the protocol, PrimeC slowed progression by 37,4%.

The benefits continued in the open-label extension, when all participants received treatment with PrimeC. Those who received PrimeC for an entire year (six months in the randomized part plus six months in the open-label extension) had a 43% higher survival rate than those who started on a placebo and then began taking PrimeC after six months.

Now, researchers have reported long-term data from the trial showing that patients who received PrimeC continuously lived significantly longer, on average, than those who started treatment six months later. In particular, the estimated median survival for those continuously on PrimeC was 36.3 months —more than 14 months longer than the 21.4 months for those initially assigned to a placebo. This represents a 70% increase in median survival.

After adjusting for initial factors, the researchers estimated that PrimeC reduced the risk of death by 65% compared with a placebo.

“A 65% reduction in the risk of death and a statistically significant extension in median survival of over 14 months represent a clinically meaningful benefit of notable magnitude in ALS,” said Ben-Noon.

Source: ALS News Today