How can TREM2 modulators achieve effective brain penetration while maintaining target engagement?

The Expert highlighted that INVOKE-2’s failure involved poor brain penetration and unclear target engagement. No viable solutions for overcoming blood-brain barrier limitations were identified.

Source: Debate session sess_SDA-2026-04-10-trem2-ad (Analysis: trem2-ad)

Gap closes when: (1) A novel TREM2 modulator scaffold achieves CNS free fraction >= 0.1x plasma Cmax in rodent PK studies with TREM2 occupancy >= 50% by ex vivo receptor occupancy assay; and (2) the compound reduces microglial activation markers (CSF1R, P2RY12) by >= 30% in a neuroinflammation model (LPS challenge or 5xFAD mice) at a dose with acceptable tolerability (no > 20% body weight loss); and (3) clinical translation feasibility is supported by PET ligand development allowing non-invasive target engagement measurement. Deliverable: PK/PD report, target engagement data, and PET tracer feasibility assessment.