title: Characterization of FRM-36143 as a new γ-secretase modulator for the potential treatment of familial Alzheimer's disease.
abstract: Familial Alzheimer's disease (FAD) is caused by mutations in the amyloid precursor protein (APP) or presenilin (PS). Most PS mutations, which account for the majority of FAD cases, lead to an increased ratio of longer to shorter forms of the amyloid beta (Aβ) peptide. The therapeutic rationale of γ-secretase modulators (GSMs) for Alzheimer's disease is based on this genetic evidence as well as on enzyme kinetics measurements showing changes in the processivity of the γ-secretase complex. This analysis suggests that GSMs could potentially offset some of the effects of PS mutations on APP processing, thereby addressing the root cause of early onset FAD. Unfortunately, the field has generated few, if any, molecules with good central nervous system (CNS) drug-like properties to enable proof-of-mechanism studies.
  
  
  
  We characterized the novel GSM FRM-36143 using multiple cellular assays to determine its in vitro potency and off-target activity as well as its potential to reverse the effect of PS mutations. We also tested its efficacy in vivo in wild-type mice and rats.
  
  
  
  FRM-36143 has much improved CNS drug-like properties compared to published GSMs. It has an in vitro EC50 for Aβ42 of 35 nM in H4 cells, can reduce Aβ42 to 58 % of the baseline in rat cerebrospinal fluid, and also increases the non-amyloidogenic peptides Aβ37 and Aβ38. It does not inhibit Notch processing, nor does it inhibit 24-dehydrocholesterol reductase (DHCR24) activity. Most interestingly, it can reverse the effects of presenilin mutations on APP processing in vitro.
  
  
  
  FRM-36143 possesses all the characteristics of a GSM in terms of Aβ modulation Because FRM-36143 was able to reverse the effect of PS mutations, we suggest that targeting patients with this genetic defect would be the best approach at testing the efficacy of a GSM in the clinic. While the amyloid hypothesis is still being tested with β-site APP-cleaving enzyme inhibitors and monoclonal antibodies in sporadic AD, we believe it is not a hypothesis for FAD. Since GSMs can correct the molecular defect caused by PS mutations, they have the promise to provide benefits to the patients when treated early enough in the course of the disease.
authors: FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA. jean-francois.blain@mail.mcgill.ca.
authors: Jean-François
authors: 0000-0003-0568-0837
authors: JF
authors: Blain
authors: FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA.
authors: Matthew G
authors: MG
authors: Bursavich
authors: FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA.
authors: Emily A
authors: EA
authors: Freeman
authors: FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA.
authors: Lori A
authors: LA
authors: Hrdlicka
authors: FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA.
authors: Hilliary E
authors: HE
authors: Hodgdon
authors: FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA.
authors: Ting
authors: T
authors: Chen
authors: FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA.
authors: Don E
authors: DE
authors: Costa
authors: FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA.
authors: Bryce A
authors: BA
authors: Harrison
authors: FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA.
authors: Sudarshan
authors: S
authors: Kapadnis
authors: FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA.
authors: Deirdre A
authors: DA
authors: Murphy
authors: FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA.
authors: Scott
authors: S
authors: Nolan
authors: FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA.
authors: Zhiming
authors: Z
authors: Tu
authors: FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA.
authors: Cuyue
authors: C
authors: Tang
authors: FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA.
authors: Duane A
authors: DA
authors: Burnett
authors: FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA.
authors: Holger
authors: H
authors: Patzke
authors: FORUM Pharmaceuticals Inc, 225 2nd Avenue, Waltham, MA, 02451, USA.
authors: Gerhard
authors: G
authors: Koenig
mesh_terms: D000544:Alzheimer Disease / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D053829:Amyloid Precursor Protein Secretases / Q000378:metabolism*; D016229:Amyloid beta-Peptides / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D045744:Cell Line, Tumor; D004353:Drug Evaluation, Preclinical; D057809:HEK293 Cells; D006367:HeLa Cells; D006576:Heterocyclic Compounds, 4 or More Rings / Q000493:pharmacokinetics / Q000627:therapeutic use* / Q000633:toxicity; D006801:Humans; D008297:Male; D051379:Mice; D057507:Mice, 129 Strain; D009154:Mutation; D019579:Neocortex / Q000187:drug effects / Q000378:metabolism; D018697:Nootropic Agents / Q000493:pharmacokinetics / Q000627:therapeutic use* / Q000633:toxicity; D053764:Presenilin-1 / Q000235:genetics / Q000378:metabolism; D017208:Rats, Wistar
chemical_list: D016229:Amyloid beta-Peptides; C000623363:FRM-36143; D006576:Heterocyclic Compounds, 4 or More Rings; D018697:Nootropic Agents; C508853:PSEN1 protein, human; D053764:Presenilin-1; D053829:Amyloid Precursor Protein Secretases
keywords: Aggregation; Aβ; Brain; CSF; Cerebrospinal fluid; Drug-like properties; Familial Alzheimer’s disease; Mutations; Presenilin; γ-Secretase modulator