Transthyretin stabilization activity of the catechol- O-methyltransferase inhibitor tolcapone (SOM0226) in hereditary ATTR amyloidosis patients and asymptomatic carriers: proof-of-concept study

Amyloid. 2019 Jun;26(2):74-84. doi: 10.1080/13506129.2019.1597702. Epub 2019 May 23.


Objective: To assess the transthyretin (TTR) stabilization activity of tolcapone (SOM0226) in patients with hereditary ATTR amyloidosis, asymptomatic carriers and healthy volunteers. Methods: A phase IIa proof-of-concept trial included two phases separated by a 6-week washout period. Phase A: single 200 mg dose of tolcapone; phase B: three 100 mg doses taken at 4 h intervals. The primary efficacy variable was TTR stabilization. Results: Seventeen subjects were included (wild type, n = 6; mutation TTR Val30Met, n = 11). TTR stabilization was observed in all participants. Two hours after dosing, 82% of participants in phase A and 93% of those in phase B reached a TTR stabilization value of at least 20%. In phase A, there was an increase of 52% in TTR stabilization vs baseline values 2 h after dosing, which decreased to 22.9% at 8 h. In phase B, there was a significant increase of 38.8% in TTR stabilization 2 h after the first 100 mg dose. This difference was maintained after 10 h and decreased after 24 h. No serious adverse events were observed. Conclusions: The ability of tolcapone for stabilizing TTR supports further development and repositioning of the drug for the treatment of ATTR amyloidosis. EudraCT trial number: 2014-001586-27 Identifier: NCT02191826.

Keywords: Amyloidogenesis inhibitor; TTR aggregation; TTR stabilization; catechol O-methyltransferase inhibitors; drug repositioning; drug repurposing; hereditary ATTR amyloidosis; proof-of-concept; tolcapone; transthyretin.

Publication types

  • Clinical Trial, Phase II

MeSH terms

  • Adult
  • Aged
  • Amyloid Neuropathies, Familial / drug therapy*
  • Amyloid Neuropathies, Familial / metabolism
  • Catechol O-Methyltransferase Inhibitors / therapeutic use
  • Female
  • Humans
  • Male
  • Middle Aged
  • Mutation, Missense
  • Prealbumin / genetics
  • Prealbumin / metabolism*
  • Proof of Concept Study*
  • Protein Aggregation, Pathological / prevention & control*
  • Tolcapone / pharmacology
  • Tolcapone / therapeutic use*


  • Catechol O-Methyltransferase Inhibitors
  • Prealbumin
  • Tolcapone

Supplementary concepts

  • Amyloidosis, Hereditary, Transthyretin-Related

Associated data