AC Immune SA (NASDAQ:ACIU) shares gained 3.9% in premarket trading on Thursday after the clinical-stage biopharmaceutical company reported preliminary Phase 1 results for ACI-19764, its experimental NLRP3 inflammasome inhibitor.
The early findings showed that the orally administered small-molecule drug was safe and well tolerated across single and multiple ascending-dose cohorts involving healthy volunteers in Europe.
ACI-19764 shows favourable safety and pharmacokinetic profile
AC Immune said no serious adverse events or treatment withdrawals have been reported to date.
The candidate also demonstrated penetration into the brain based on cerebrospinal fluid exposure and recorded a serum half-life of more than 30 hours, potentially supporting once-daily dosing.
Daily doses of 10mg or less produced pharmacokinetic concentrations above the IC90 threshold. A blinded assessment of whole-blood assay results also indicated dose-dependent inhibition of IL-1beta release, providing preliminary evidence of the drug’s intended biological activity.
Based on the pharmacokinetic findings so far, AC Immune expects the therapeutic dose could be 10mg or less once per day. The single ascending-dose portion of the study evaluated doses as high as 20mg daily.
Phase 1b testing expands into cardiovascular risk patients
The clinical programme has now moved into a Phase 1b cohort involving patients considered at increased risk of cardiovascular disease.
Eligibility is determined by elevated serum levels of high-sensitivity C-reactive protein together with either type 2 diabetes or obesity. Initial results from this patient cohort are expected by the end of the year.
AC Immune expects to report complete results from the Phase 1/1b programme during the first half of 2027.
NLRP3 programme targets chronic inflammation
ACI-19764 is designed to inhibit the NLRP3 inflammasome, which plays a role in generating pro-inflammatory factors associated with chronic inflammation and disease progression.
AC Immune sees potential applications across inflammatory disorders, metabolic conditions and neurological diseases.
Preclinical testing has demonstrated high in-vitro potency, including downstream inhibition of IL-1β production in human macrophages and whole blood, with an IC50 range of 2-20.5nM.
The combination of favourable early safety findings, evidence of brain penetration and dose-dependent biological activity helped support the positive reaction in AC Immune shares following the Phase 1 update.