AC Immune Presents New Phase 1 Data Indicating Higher Uptake of TDP-43 PET Tracer ACI-19626 in Patients with ALS

  • Presentation at 2026 TDP43 Summit shows ACI-19626 detects TDP-43 pathology in patients with amyotrophic lateral sclerosis (ALS)
  • Previously reported data also showed detection of TDP-43 in patients with genetically defined frontotemporal dementia (FTD)
  • Underlines potential for precision medicine enabling early diagnosis and intervention in multiple neurodegenerative diseases

AC Immune SA (NASDAQ:ACIU), a clinical-stage biopharmaceutical company pioneering precision therapeutics for neurodegenerative diseases, today announced the presentation of new preliminary data from a Phase 1 trial of its first-in-class TDP-43 positron emission tomography (PET) tracer ACI-19626 showing increased uptake in the brains of patients with amyotrophic lateral sclerosis (ALS).

The results presented at the 2026 TDP43 Summit in Madison, Wisconsin, demonstrate that PET scans with ACI-19626 showed tracer uptake significantly higher in key regions of the brain in patients with ALS compared to healthy controls. Specifically, tracer uptake was higher in the brain stem (* see image below) and precentral gyrus, where TDP-43 pathology is expected to accumulate based on post-mortem neuropathology studies and on clinical symptoms. Previously reported data showed significantly higher tracer uptake in disease-relevant subcortical and cortical regions in patients with genetic frontotemporal dementia (FTD).

ACI-19626 continues to show good safety and tolerability, a dosimetry profile within accepted limits, and rapid brain uptake and washout, indicating a pharmacokinetic (PK) profile suitable for human brain imaging and potentially pharmacodynamic analysis of therapeutics targeting TDP-43 pathology.