Acid sphingomyelinase (ASM, encoded by SMPD1) inhibitors represent an emerging therapeutic approach within the ceramide/sphingolipid pathway for neurodegenerative diseases. ASM catalyzes the hydrolysis of sphingomyelin to ceramide:
Sphingomyelin + H2O → Ceramide + Phosphocholine
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ASM (SMPD1)
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ASM inhibitors
Elevated ASM activity contributes to excess ceramide generation in neurodegeneration, promoting apoptosis, neuroinflammation, and protein aggregation. ASM inhibitors reduce ceramide accumulation from the sphingomyelin catabolism pathway — complementary to ceramide synthase inhibitors (which block de novo ceramide synthesis) and glucosylceramide synthase inhibitors (which block downstream conversion).
Company: Sanofi (formerly in partnership with AeXceed)
Mechanism: Selective ASM inhibitor; reduces ceramide generation from sphingomyelin hydrolysis[1].
Development:
Clinical Data:
Company: Biobo Pharma (Germany)
Mechanism: Novel ASM inhibitor with enhanced brain penetration.
Development:
Company: Ceramiden Therapeutics (Cambridge, MA) — a biotechnology startup focused on sphingolipid biology.
Pipeline:
Partnerships:
Company: Lipimetix (Boston, MA)
Focus: Peptide-based sphingolipid modulators with novel mechanisms.
Assets:
Mechanism: Tricyclic antidepressant with off-target ASM inhibitory activity at therapeutic concentrations[3].
Evidence:
Clinical Trials:
| Trial | Phase | Indication | Status |
|---|---|---|---|
| AMIT-PD | Phase 2 | Parkinson's disease | Recruiting (NCT05014562) |
| ASM-AD | Phase 2 | Alzheimer's disease | Planning |
Rationale: The established safety profile of amitriptyline (decades of clinical use) enables rapid evaluation in neurodegeneration.
Mechanism: Tricyclic antidepressant with ASM inhibitory properties similar to amitriptyline[3:1].
Status:
| Target | Enzyme | Pathway Position | Agent Class | Stage |
|---|---|---|---|---|
| ASM | SMPD1 | Sphingomyelin → Ceramide | Inhibitors | Preclinical/Phase 2 |
| CerS | CERS1-6 | Sphinganine → Ceramide | Inhibitors | Preclinical |
| GCS | GBA2 | Ceramide → GlcCer | Inhibitors | Phase 2 (eliglustat, venglustat) |
| S1PK | SPHK1/2 | Sphingosine → S1P | Inhibitors/agonists | S1P modulators approved (MS) |
| Ceramidase | ASAH1 | Ceramide → Sphingosine | Inhibitors | Preclinical |
| Agent | Type | Company | Indication | Phase |
|---|---|---|---|---|
| Olapasertan (ASP1618) | ASM inhibitor | Sanofi | PD, NP-A/B | Phase 2 (NP); PD planned |
| BBP-831 | ASM inhibitor | Biobo Pharma | PD | Preclinical |
| CT-001 | ASM inhibitor | Ceramiden | PD | IND-enabling |
| Amitriptyline | Off-label ASM inhibitor | Generic | PD | Phase 2 (NCT05014562) |
| CT-002 | Dual ASM/CerS | Ceramiden | ALS, FTD | Preclinical |
Schuchman EH et al. ASM inhibitors in neurodegeneration: a new therapeutic strategy. Neurobiol Dis. 2016. ↩︎
Gomez JC et al. ASM inhibition reduces neuroinflammation in PD models. J Neuroinflammation. 2019. ↩︎ ↩︎
Harzer K et al. Amitriptyline and desipramine for ASM inhibition. Neurochem Res. 2012. ↩︎ ↩︎