title: Effect of opicapone and entacapone upon levodopa pharmacokinetics during three daily levodopa administrations.
abstract: OBJECTIVE
  Opicapone is a novel third generation catechol-O-methyltransferase (COMT) inhibitor. The purpose of this study was to compare the levodopa pharmacokinetic profile throughout a day driven by the COMT inhibition either following repeated doses of opicapone or concomitant administration with entacapone.
  
  
  METHODS
  A randomized, double-blind, gender-balanced, parallel-group study was performed in 4 groups of 20 healthy subjects each. Four subjects in each group received placebo during the entire study. Sixteen subjects in one group received placebo once daily for 11 days and on day 12, 200 mg entacapone concomitantly with each levodopa/carbidopa dose (three times separated by a 5-h interval). Sixteen subjects in each of the remaining three groups received respectively 25, 50, and 75 mg opicapone once daily for 11 days and on day 12, placebo concomitantly with each levodopa/carbidopa dose.
  
  
  RESULTS
  Levodopa minimum plasma concentration (Cmin) for each levodopa/carbidopa dose and for the mean of all levodopa/carbidopa doses increased substantially with all active treatments (entacapone and opicapone) when compared to the control group (placebo), with values ranging from 1.7-fold (200 mg entacapone) to 3.3-fold (75 mg opicapone). No statistical difference was found for levodopa peak of systemic exposure (as assessed by maximum observed plasma concentration (Cmax)) between all active treatments and placebo. A significant increase in the levodopa extent of systemic exposure (as assessed by concentration-time curve (AUC)) occurred with all opicapone treatments in relation to placebo. No statistical difference was found for levodopa AUC when entacapone was compared to placebo. When compared to entacapone, both 50 and 75 mg opicapone presented a significant increase for the levodopa AUC. All active treatments significantly inhibited both peak (as assessed by Emax) and extent (as assessed by effect-time curve (AUEC)) of the COMT activity in relation to placebo. When compared to entacapone, all opicapone treatments significantly decreased the extent (AUEC) of the COMT activity due to a long-lasting and sustained effect. The tolerability profile was favorable for all active treatments.
  
  
  CONCLUSIONS
  Opicapone, a novel third generation COMT inhibitor, when compared to entacapone, provides a superior response upon the bioavailability of levodopa associated to more pronounced, long-lasting, and sustained COMT inhibition. The tolerability profile was favorable. On the basis of the results presented in this study and along with the earlier pharmacology studies, it is anticipated that opicapone adjunct therapy at the dosages of 25 and 50 mg will provide an enhancement in levodopa availability that will translate into clinical benefit for Parkinson's disease patients.
authors.affiliation: Department Research and Development, BIAL-Portela & Cª, S.A., À Av. da Siderurgia Nacional, 4745-457, S. Mamede do Coronado, Portugal.
authors.forename: José-Francisco
authors.initials: JF
authors.lastname: Rocha
authors.forename: Amílcar
authors.initials: A
authors.lastname: Falcão
authors.forename: Ana
authors.initials: A
authors.lastname: Santos
authors.forename: Roberto
authors.initials: R
authors.lastname: Pinto
authors.forename: Nelson
authors.initials: N
authors.lastname: Lopes
authors.forename: Teresa
authors.initials: T
authors.lastname: Nunes
authors.forename: Lyndon C
authors.initials: LC
authors.lastname: Wright
authors.forename: Manuel
authors.initials: M
authors.lastname: Vaz-da-Silva
authors.forename: Patrício
authors.initials: P
authors.lastname: Soares-da-Silva
mesh_terms: D000328:Adult; D000978:Antiparkinson Agents / Q000009:adverse effects / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology; D019540:Area Under Curve; D002394:Catechol O-Methyltransferase / Q000378:metabolism; D065098:Catechol O-Methyltransferase Inhibitors / Q000009:adverse effects / Q000494:pharmacology*; D002396:Catechols / Q000009:adverse effects / Q000494:pharmacology*; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D004347:Drug Interactions; D005260:Female; D006801:Humans; D007980:Levodopa / Q000008:administration & dosage / Q000009:adverse effects / Q000097:blood / Q000493:pharmacokinetics*; D008297:Male; D008875:Middle Aged; D009570:Nitriles / Q000009:adverse effects / Q000494:pharmacology*; D010069:Oxadiazoles / Q000009:adverse effects / Q000494:pharmacology*; D055815:Young Adult
chemical_list: D000978:Antiparkinson Agents; D065098:Catechol O-Methyltransferase Inhibitors; D002396:Catechols; D009570:Nitriles; D010069:Oxadiazoles; D007980:Levodopa; C071192:entacapone; D002394:Catechol O-Methyltransferase; C549349:opicapone