Pharmacotherapeutic group: Ophthalmologicals, anti-inflammatory agents, non-steroids, ATC code: S01BC10
Mechanism of action
Nepafenac is a non-steroidal anti-inflammatory and analgesic prodrug. After topical ocular dosing, nepafenac penetrates the cornea and is converted by ocular tissue hydrolases to amfenac, a nonsteroidal anti-inflammatory drug. Amfenac inhibits the action of prostaglandin H synthase (cyclooxygenase), an enzyme required for prostaglandin production.
Secondary pharmacology
In rabbits, nepafenac has been shown to inhibit blood-retinal-barrier breakdown, concomitant with suppression of PGE2 synthesis. Ex vivo, a single topical ocular dose of nepafenac was shown to inhibit prostaglandin synthesis in the iris/ciliary body (85%-95%) and the retina/choroid (55%) for up to 6 hours and 4 hours, respectively.
Pharmacodynamic effects
The majority of hydrolytic conversion is in the retina/choroid followed by the iris/ciliary body and cornea, consistent with the degree of vascularised tissue.
Results from clinical studies indicate that NEVANAC 3 mg/ml eye drops, suspension have no significant effect on intraocular pressure.
Clinical efficacy and safety
Prevention and treatment of postoperative pain and inflammation associated with cataract surgery
The efficacy and safety of NEVANAC 3 mg/ml in the prevention and treatment of postoperative pain and inflammation associated with cataract surgery has been demonstrated in two masked, double blind, placebo-controlled clinical trials in a total of 1 339 patients. In these studies in which patients were dosed daily beginning one day prior to cataract surgery, continued on the day of surgery and for the first 14 days of the postoperative period, NEVANAC 3 mg/ml eye drops, suspension demonstrated superior clinical efficacy compared to its vehicle in treating postoperative pain and inflammation.
Patients treated with NEVANAC were less likely to have ocular pain and measurable signs of inflammation (aqueous cells and flare) in the early postoperative period through to the end of treatment than those treated with its vehicle. In the two studies, NEVANAC cleared inflammation at day 14 post operation in 65% and 68% of patients compared to 25% and 35% of patients on vehicle. Pain free rates in the NEVANAC group were 89% and 91% compared to 40% and 50% of patients on vehicle.
Some patients received NEVANAC 3 mg/ml eye drops, suspension for up to 21 days post operation. However, efficacy beyond day 14 post operation was not measured.
In addition, in one of the two clinical trials, NEVANAC 3 mg/ml eye drops, suspension dosed once a day was non-inferior to NEVANAC 1 mg/ml eye drops, suspension dosed three times a day for the prevention and treatment of postoperative pain and inflammation following cataract surgery. Inflammation clearing and pain free rates were similar for both products at all postoperative evaluations.
Reduction in the risk of postoperative macular oedema associated with cataract surgery in diabetic patients
Two studies in diabetic patients were conducted to assess the efficacy and safety of NEVANAC 3 mg/ml eye drops, suspension dosed once a day for the prevention of postoperative macular oedema associated with cataract surgery. In these studies, study medication was initiated the day prior to surgery, continued on the day of surgery and for up to 90 days of the postoperative period.
In both double-masked, randomised vehicle-controlled studies, conducted in diabetic retinopathy patients, a significantly greater percentage of patients in the vehicle group developed macular oedema (17.3% and 14.3%) compared to patients treated with NEVANAC 3 mg/ml (2.3% and 5.9%). The corresponding percentages in integrated analysis of the 2 studies were 15.9% in vehicle group and 4.1% in NEVANAC group, p<0.001). A significantly greater percentage of patients achieved improvement of 15 or more letters at Day 14 and maintained the improvement through Day 90 in NEVANAC 3 mg/ml group (61.7%) compared to vehicle group (43%) in one study; the percentage of subjects was similar in the 2 treatment groups for this endpoint in the second study (48.8% in NEVANAC group and 50.5% in vehicle group). In integrated analysis of the 2 studies, the percentage of subjects with 15 letter improvement at Day 14 and maintained to Day 90 was higher in NEVANAC 3 mg/ml group (55.4%) compared to vehicle group (46.7%, p=0.003).
Paediatric population
The European Medicines Agency has waived the obligation to submit the results of studies with NEVANAC in all subsets of the paediatric population in prevention and treatment of post operative pain and inflammation associated with cataract surgery (see section 4.2 for information on paediatric use).