Pharmacotherapeutic group: Opthalmologicals, 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 eye drops have no significant effect on intraocular pressure.
Clinical efficacy and safety
Prevention and treatment of postoperative pain and inflammation associated with cataract surgery
Three pivotal studies were conducted to assess the efficacy and safety of NEVANAC dosed 3 times daily as compared to vehicle and/or ketorolac trometamol in the prevention and treatment of postoperative pain and inflammation in patients undergoing cataract surgery. In these studies, study medication was initiated the day prior to surgery, continued on the day of surgery and for up to 2-4 weeks of the postoperative period. Additionally, nearly all patients received prophylactic treatment with antibiotics, according to clinical practice at each of the clinical trial sites.
In two double-masked, randomised vehicle-controlled studies, patients treated with NEVANAC had significantly less inflammation (aqueous cells and flare) in the early postoperative period through the end of treatment than those treated with its vehicle.
In one double-masked, randomised, vehicle and active-controlled study, patients treated with NEVANAC had significantly less inflammation than those treated with vehicle. Additionally, NEVANAC was non-inferior to ketorolac 5 mg/ml in reducing inflammation and ocular pain, and was slightly more comfortable upon instillation.
A significantly higher percentage of patients in the NEVANAC group reported no ocular pain following cataract surgery compared to those in the vehicle group.
Reduction in the risk of postoperative macular oedema associated with cataract surgery in diabetic patients
Four studies (two in diabetic patients and two in non-diabetic patients) were conducted to assess the efficacy and safety of NEVANAC 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 1 double-masked, randomised vehicle-controlled study, conducted in diabetic retinopathy patients, a significantly greater percentage of patients in the vehicle group developed macular oedema (16.7%) compared to patients treated with NEVANAC (3.2%). A greater percentage of patients treated with vehicle experienced a decrease in BCVA of more than 5 letters from day 7 to day 90 (or early exit) (11.5%) compared with patients treated with nepafenac (5.6%). More patients treated with NEVANAC achieved a 15 letter improvement in BCVA compared to vehicle patients, 56.8% compared to 41.9%. respectively, p=0.019.
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 and prevention of post surgical macular oedema (see section 4.2 for information on paediatric use).