title: An evaluation of the rate of nonresponders to latanoprost therapy.
abstract: OBJECTIVE
  To determine the proportion of patients with primary open-angle glaucoma (POAG) or ocular hypertension (OH) who do not respond to latanoprost therapy.
  
  
  METHODS
  Three hundred forty consecutive patients with a new diagnosis of POAG or OH, or previously treated only with a beta-blocker and after an appropriate washout period, were treated with latanoprost for 1 month and then divided into three groups on the basis of the reduction in intraocular pressure (IOP): nonresponders (<15%), responders (> or =15% but <30%), and high-responders (> or =30%). To give a wide picture of the drug effect, eight different cut-off points were used to present data on distribution of mean IOP reductions. Only the nonresponders entered a randomized cross-over study investigating the efficacy of timolol, brimonidine, and pilocarpine.
  
  
  RESULTS
  IOP at baseline and after 1 month's latanoprost therapy was respectively 24.1+/-1.4 and 16.9+/-2.4 mm Hg, with a mean reduction in IOP of 29.9+/-4.2%. Nonresponders accounted for 4.1% of the patients and high-responders for 41.2%. The nonresponders showed a statistically significant reduction in IOP after brimonidine treatment (P=0.05), whereas the reduction after timolol and pilocarpine treatment was clinically relevant but not statistically significant.
  
  
  CONCLUSIONS
  This multicenter prospective study found only 14 of 340 nonresponders to latanoprost. In the cross-over trial on nonresponders, IOP reduction reached statistical significance only after brimonidine, but their small number reduced its statistical power.
authors.affiliation: San Paolo Hospital, University of Milan, Italy. lucamrossetti@libero.it
authors.forename: Luca
authors.initials: L
authors.lastname: Rossetti
authors.forename: Stefano
authors.initials: S
authors.lastname: Gandolfi
authors.forename: Carlo
authors.initials: C
authors.lastname: Traverso
authors.forename: Paolo
authors.initials: P
authors.lastname: Montanari
authors.forename: Maurizio
authors.initials: M
authors.lastname: Uva
authors.forename: Gianluca
authors.initials: G
authors.lastname: Manni
authors.forename: Roberto
authors.initials: R
authors.lastname: Carassa
authors.forename: Leonardo
authors.initials: L
authors.lastname: Mastropasqua
authors.forename: Luciano
authors.initials: L
authors.lastname: Quaranta
authors.forename: Giorgio
authors.initials: G
authors.lastname: Marchini
authors.forename: Roberto
authors.initials: R
authors.lastname: Ratiglia
authors.forename: Nicola
authors.initials: N
authors.lastname: Orzalesi
mesh_terms: D000959:Antihypertensive Agents / Q000627:therapeutic use*; D000068438:Brimonidine Tartrate; D018592:Cross-Over Studies; D004351:Drug Resistance; D005902:Glaucoma, Open-Angle / Q000188:drug therapy*; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects*; D000077338:Latanoprost; D009798:Ocular Hypertension / Q000188:drug therapy; D010862:Pilocarpine / Q000627:therapeutic use; D011446:Prospective Studies; D011461:Prostaglandins F, Synthetic / Q000627:therapeutic use*; D011810:Quinoxalines / Q000627:therapeutic use; D013999:Timolol / Q000627:therapeutic use; D014065:Tonometry, Ocular
chemical_list: D000959:Antihypertensive Agents; D011461:Prostaglandins F, Synthetic; D011810:Quinoxalines; D010862:Pilocarpine; D000068438:Brimonidine Tartrate; D000077338:Latanoprost; D013999:Timolol