AZP2006 (development code; international nonproprietary name: serazaxine) is an oral pleiotropic neuroprotective drug developed by Aztherapi Ltd. It was selected for the PSP Platform Trial alongside AADvac1 based on Phase 2a results showing encouraging clinical and biomarker signals in patients with Progressive Supranuclear Palsy (PSP)[1].
Unlike most PSP pipeline agents that target tau directly (antisense oligonucleotides, immunotherapies, O-GlcNAcylation modulators), AZP2006 works through a progranulin-dependent lysosomal pathway — a distinct mechanistic approach that aims to preserve synaptic function and slow neurodegeneration without directly engaging the tau pathology itself[1:1].
AZP2006's therapeutic effect is mediated through modulation of progranulin (PGRN) levels and consequent enhancement of lysosomal function[1:2].
Progranulin (gene: GRN, protein encoded) is a secreted glycoprotein with critical roles in neuronal survival, lysosomal function, and inflammation. Loss-of-function mutations in GRN cause a significant proportion of familial frontotemporal dementia, and progranulin deficiency is implicated in a broader range of neurodegenerative conditions including PSP and corticobasal syndrome[1:3].
Key progranulin functions relevant to tauopathies:
AZP2006 acts as an oral small molecule that upregulates progranulin expression and stabilizes circulating progranulin levels. This, in turn, enhances lysosomal clearance capacity, reduces accumulation of pathologic aggregates, and provides neuroprotection to vulnerable neuronal populations — particularly GABAergic neurons that are preferentially affected in PSP[1:4].
The fact that AZP2006 does NOT directly target tau makes it a complementary mechanism to anti-tau therapies (AADvac1, E2814, BIIB080). Combining a progranulin/lysosome enhancer with an anti-tau immunotherapy represents a rational multi-target strategy for PSP[1:5].
| Parameter | Details |
|---|---|
| Design | Multicenter, randomized, double-blind, placebo-controlled, parallel-group |
| Sites | 3 sites in France |
| Enrollment | 41 screened, 36 randomized, 34 completed |
| Population | Patients aged 40-80 years with probable or possible PSP |
| Duration | 12 weeks |
| Dosing | 60 mg QD, 80/50 mg QD, or placebo |
| Primary Endpoints | Safety, tolerability, pharmacokinetics |
| Secondary Endpoints | Pharmacodynamics (CSF/plasma biomarkers), PSP Rating Scale (PSPRS), Clinical Global Impression, Activities of Daily Living |
Efficacy Results: Trends in efficacy favored slower disease progression in AZP2006 treatment groups vs. placebo, as measured by the PSP Rating Scale[1:6].
Pharmacokinetics:
| Parameter | Details |
|---|---|
| Participants | 15 patients who completed Phase 2a |
| Duration | 6 months |
| Results | No notable safety concerns; continued biomarker stabilization |
The 6-month OLE confirmed sustained safety and continued evidence of target engagement with stabilized progranulin levels[1:8].
AZP2006 demonstrated acceptable tolerability and safety across all dosing cohorts[1:9]:
The favorable safety profile, combined with the novel mechanism of action, supported AZP2006's selection for the adaptive PSP Platform Trial[1:10].
The Phase 2a study incorporated extensive biomarker analyses:
| Biomarker | Finding |
|---|---|
| Blood-brain barrier penetration | Confirmed — AZP2006 achieves CNS exposure in humans |
| Target engagement | Demonstrated — progranulin levels stabilized in treated patients |
| CSF biomarkers | Pharmacodynamic changes consistent with lysosomal pathway modulation |
| Plasma pharmacokinetics | Dose-proportional exposure; long half-life supports QD dosing |
AZP2006 was selected alongside AADvac1 (a tau-targeting active immunotherapy) for the PSP Platform Trial, an adaptive design study in PSP patients[1:11]. This multi-arm platform design enables efficient evaluation of multiple therapeutic candidates simultaneously.
The complementary mechanisms — AZP2006 (progranulin/lysosome enhancement) + AADvac1 (anti-tau immunotherapy) — reflect a growing consensus that combination approaches will be needed to meaningfully slow PSP progression[1:12].
See the CBS/PSP Cure Roadmap and Tau-Targeted Therapeutics pages for broader context on the PSP therapeutic landscape.
| Agent | Target | Mechanism | Stage | Distinctive Feature |
|---|---|---|---|---|
| AZP2006 | Progranulin / Lysosome | Neuroprotection via PGRN modulation | Phase 2a positive | MAPT-independent; complementary to anti-tau |
| AADvac1 | Tau | Active immunotherapy | Phase 2 (PSP platform) | Direct anti-tau antibody generation |
| Lithium | GSK-3β | Reduce tau phosphorylation | Phase 2 | Off-patent; widely available |
| Tideglusib | GSK-3β | Reduce tau phosphorylation | Phase 2 (failed) | No clinical benefit in PSP |
| Davunetide | Microtubule | Microtubule stabilization | Phase 2 (failed) | Failed primary endpoint |
| Neflamapimod | p38 MAPK | Anti-inflammatory | Phase 2 | Failed to meet primary endpoint |
| FNP-223 | OGT | Increase tau O-GlcNAcylation | Phase 2 (PROSPER trial) | Direct tau PTM modulation; results 2026 |
AZP2006's MAPT-independent mechanism distinguishes it from the majority of PSP therapies, making it valuable as a complementary or rescue approach for patients who cannot tolerate or do not respond to anti-tau strategies.
For patients with atypical parkinsonism (CBS/PSP spectrum):
Potential Advantages:
Considerations:
For the patient profile (50-year-old male, suspected CBS/PSP, on levodopa + rasagiline), AZP2006 represents a disease-modifying candidate with a novel mechanism that complements existing dopaminergic therapy. Enrollment in the PSP Platform Trial would provide access to this and other emerging therapies under close clinical monitoring.