title: Latanoprost systemic exposure in pediatric and adult patients with glaucoma: a phase 1, open-label study.
abstract: OBJECTIVE
  To evaluate short-term safety and steady-state systemic pharmacokinetics (PK) of latanoprost acid in pediatric subjects with glaucoma or ocular hypertension who received the adult latanoprost dose.
  
  
  METHODS
  Phase 1, open-label, multicenter study.
  
  
  METHODS
  Pediatric patients of 3 age groups (<3, 3-<12, and 12-<18 years) and adults (≥18 years) receiving latanoprost ophthalmic solution 0.005% once daily in 1 or both eyes for ≥2 weeks.
  
  
  METHODS
  Latanoprost was administered in both eyes each morning post-screening. Subjects returned 3 to 28 days later for evaluation of plasma concentrations, withholding morning latanoprost. At the clinic, a single drop of latanoprost ophthalmic solution was instilled into both eyes. Plasma latanoprost acid concentrations were collected predose and 5, 15, 30, and 60 minutes after administration.
  
  
  METHODS
  Latanoprost acid plasma exposure.
  
  
  RESULTS
  The evaluable PK analysis set included data from 39 of 47 enrolled subjects. The median peak plasma concentration value was higher in the <3-year age group (166 pg/ml) versus other groups (49, 16, and 26 pg/ml for the 3-<12-year, 12-<18-year, and ≥18-year age groups, respectively). The median area under the concentration-time curve from zero to last measurable concentration value was also higher in the <3-year age group (2716 pg/min/ml) versus other groups (588, 106, and 380 pg/min/ml for the 3-<12-year, 12-<18-year, and ≥18-year age groups, respectively). Latanoprost acid was rapidly eliminated from the blood, with plasma concentrations undetectable within 10 to 30 minutes postdose in all but the <3-year age group. There were no discontinuations or dose reductions due to adverse events or treatment-emergent adverse events.
  
  
  CONCLUSIONS
  Latanoprost acid systemic exposure was higher in younger children versus adolescents and adults, attributed primarily to lower body weight and smaller blood volume. Latanoprost acid was eliminated rapidly in all age groups and resulted in only a brief period of systemic exposure after once-daily dosing. Higher systemic exposure was not accompanied by adverse events, and on the basis of extrapolation of safety data from adults, this pilot study suggests an adequate safety margin for systemic adverse effects with use of the adult topical dose of latanoprost in pediatric patients.
  
  
  BACKGROUND
  Proprietary or commercial disclosures may be found after the references.
authors.affiliation: Pfizer Inc., San Diego, California, USA. susan.raber@pfizer.com
authors.forename: Susan
authors.initials: S
authors.lastname: Raber
authors.forename: Rachel
authors.initials: R
authors.lastname: Courtney
authors.forename: Tomoko
authors.initials: T
authors.lastname: Maeda-Chubachi
authors.forename: Brad D
authors.initials: BD
authors.lastname: Simons
authors.forename: Sharon F
authors.initials: SF
authors.lastname: Freedman
authors.forename: Barbara
authors.initials: B
authors.lastname: Wirostko
mesh_terms: D000287:Administration, Topical; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000959:Antihypertensive Agents / Q000009:adverse effects / Q000493:pharmacokinetics*; D001682:Biological Availability; D002648:Child; D002675:Child, Preschool; D005260:Female; D005901:Glaucoma / Q000378:metabolism*; D006801:Humans; D006871:Hydrophthalmos / Q000378:metabolism*; D007223:Infant; D007429:Intraocular Pressure / Q000187:drug effects; D000077338:Latanoprost; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000378:metabolism; D009883:Ophthalmic Solutions / Q000009:adverse effects / Q000493:pharmacokinetics; D011446:Prospective Studies; D011461:Prostaglandins F, Synthetic / Q000009:adverse effects / Q000493:pharmacokinetics*; D014065:Tonometry, Ocular
chemical_list: D000959:Antihypertensive Agents; D009883:Ophthalmic Solutions; D011461:Prostaglandins F, Synthetic; D000077338:Latanoprost