Bimagan

Reduction of elevated intraocular pressure in chronic open-angle glaucoma and ocular hypertension in adults (as monotherapy or as adjunctive therapy to beta-blockers).

Posology

The recommended dose is one drop in the affected eye(s) once daily, administered in the evening. The dose should not exceed once daily as more frequent administration may lessen the intraocular pressure lowering effect.

For single use only, one container is sufficient to treat both eyes. Any unused solution should be discarded immediately after use.

Paediatric population:

The safety and efficacy of Bimagan in children aged 0 to 18 years has not yet been established.

Patients with hepatic and renal impairment:

Bimagan has not been studied in patients with renal or moderate to severe hepatic impairment and should therefore be used with caution in such patients. In patients with a history of mild liver disease or abnormal alanine aminotransferase (ALT), aspartate aminotransferase (AST) and/or bilirubin at baseline, bimatoprost 0.3 mg/mL eye drops (multi-dose formulation), solution had no adverse effect on liver function over 24 months.

Method of administration

If more than one topical ophthalmic medicinal product is being used, each one should be administered at least 5 minutes apart.

Ocular

Before treatment is initiated, patients should be informed of the possibility of eyelash growth, darkening of the eyelid skin and increased iris pigmentation since these have been observed during treatment with Bimagan. Some of these changes may be permanent, and may lead to differences in appearance between the eyes when only one eye is treated. Increased iris pigmentation is likely to be permanent. The pigmentation change is due to increased melanin content in the melanocytes rather than to an increase in the number of melanocytes. The long term effects of increased iris pigmentation are not known. Iris colour changes seen with ophthalmic administration of bimatoprost may not be noticeable for several months to years. Typically, the brown pigmentation around the pupil spreads concentrically towards the periphery of the iris and the entire iris or parts become more brownish. Neither naevi nor freckles of the iris appear to be affected by the treatment. At 3 months, the incidence of iris hyperpigmentation with bimatoprost 0.3 mg/mL single dose was 0.3%. At 12 months, the incidence of iris pigmentation with bimatoprost 0.3 mg/mL (multi-dose formulation) was 1.5% and did not increase following 3 years treatment. Periorbital tissue pigmentation has been reported to be reversible in some patients.

Cystoid macular oedema has been uncommonly reported (>1/1,000 to <1/100) following treatment with bimatoprost 0.3 mg/mL eye drops (multi-dose formulation). Therefore, Bimagan should be used with caution in patients with known risk factors for macular oedema (e.g. aphakic patients, pseudophakic patients with a torn posterior lens capsule).

There have been rare spontaneous reports of reactivation of previous corneal infiltrates or ocular infections with bimatoprost 0.3 mg/mL eye drops, solution (multi-dose formulation). Bimagan should be used with caution in patients with a prior history of significant ocular viral infections (e.g. herpes simplex) or uveitis/iritis.

Bimagan has not been studied in patients with inflammatory ocular conditions, neovascular, inflammatory, angle-closure glaucoma, congenital glaucoma or narrow-angle glaucoma.

Skin

There is a potential for hair growth to occur in areas where Bimagan solution comes repeatedly in contact with the skin surface. Thus, it is important to apply Bimagan as instructed and avoid it running onto the cheek or other skin areas.

Respiratory

Bimagan has not been studied in patients with compromised respiratory function. While there is limited information available on patients with a history of asthma or COPD, there have been reports of exacerbation of asthma, dyspnoea and COPD, as well as reports of asthma, in post marketing experience. The frequency of these symptoms is not known. Patients with COPD, asthma or compromised respiratory function due to other conditions should be treated with caution.

Cardiovascular

Bimagan has not been studied in patients with heart block more severe than first degree or uncontrolled congestive heart failure. There have been a limited number of spontaneous reports of bradycardia or hypotension with bimatoprost 0.3 mg/mL eye drops, solution (multi-dose formulation). Bimagan should be used with caution in patients predisposed to low heart rate or low blood pressure.

Other Information

In studies of bimatoprost 0.3 mg/ml in patients with glaucoma or ocular hypertension, it has been shown that the more frequent exposure of the eye to more than one dose of bimatoprost daily may decrease the IOP-lowering effect. Patients using Bimagan with other prostaglandin analogues should be monitored for changes to their intraocular pressure.

Bimagan 0.3 mg/mL single-dose has not been studied in patients wearing contact lenses.

Contact lenses should be removed prior to instillation and may be reinserted 15 minutes following administration.

Bimagan has negligible influence on the ability to drive and use machines. As with any ocular treatment, if transient blurred vision occurs at instillation, the patient should wait until the vision clears before driving or using machines.

In a 3 month clinical study, approximately 29% of patients treated with Bimagan 0.3 mg/mL single-dose experienced adverse reactions. The most frequently reported adverse reactions were conjuctival hyperaemia (mostly trace to mild and of a non-inflammatory nature) occurring in 24% of patients, and eye pruritis occurring in 4% of patients. Approximately 0.7% of patients in the Bimagan 0.3 mg/mL single-dose group discontinued due to any adverse event in the 3 month study.

The following adverse reactions were reported during clinical trials with Bimagan 0.3 mg/mL single-dose or in the post-marketing period. Most were ocular, mild and none was serious:

Very common (>1/10); common (>1/100 to <1/10); uncommon (>1/1,000 to <1/100); rare (>1/10,000 to <1/1,000); very rare (<1/10,000) and not known (cannot be estimated from available data) adverse reactions are presented according to System Organ Class in Table 1. Within each frequency grouping, undesirable effects are presented in order of decreasing seriousness.

Table 1

In clinical studies, over 1800 patients have been treated with Bimagan 0.3 mg/mL (multi-dose formulation). On combining the data from phase III monotherapy and adjunctive Bimagan 0.3 mg/mL (multi-dose formulation) usage, the most frequently reported adverse reactions were:

- growth of eyelashes in up to 45% in the first year with the incidence of new reports decreasing to 7% at 2 years and 2% at 3 years

- conjunctival hyperaemia (mostly trace to mild and thought to be of a non-inflammatory nature) in up to 44% in the first year with the incidence of new reports decreasing to 13% at 2 years and 12% at 3 years

- ocular pruritus in up to 14% of patients in the first year with the incidence of new reports decreasing to 3% at 2 years and 0% at 3 years.

Less than 9% of patients discontinued due to any adverse event in the first year with the incidence of additional patient discontinuations being 3% at both 2 and 3 years.

Table 2 lists adverse reactions that were seen in a 12 month clinical study with Bimagan 0.3 mg/mL (multi-dose formulation), but were reported at a higher frequency than with Bimagan 0.3 mg/mL (single-dose). Most were ocular, mild to moderate, and none were serious.

Table 2

In addition to the adverse reactions seen with Bimagan 0.3 mg/mL single-dose,Table 3 lists additional adverse reactions that were seen with Bimagan 0.3 mg/mL (multi-dose formulation).Most were ocular, mild to moderate, and none were serious.

Table 3

Adverse reactions reported in phosphate containing eye drops:

Cases of corneal calcification have been reported very rarely in association with the use of phosphate containing eye drops in some patients with significantly damaged corneas.

Reporting of suspected adverse reactions

Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme, Website: www.mhra.gov.uk/yellowcard.

No information is available on overdose in humans; overdose is unlikely to occur after ocular administration.

If overdose occurs, treatment should be symptomatic and supportive. If Bimagan 0.3 mg/mL single-dose is accidentally ingested, the following information may be useful: In short term oral (by gavage) mouse and rat studies, doses up to 100 mg/kg/day of bimatoprost did not produce any toxicity. This dose is at least 22 times higher than an accidental dose of the entire content of a pack of Bimagan 0.3 mg/mL single-dose (30 x 0.4 mL single-dose containers; 12 mL) in a 10 kg child.

Pharmacotherapeutic group: Ophthalmologicals, prostaglandin analogues, ATC code: S01EE03.

Mechanism of action

The mechanism of action by which bimatoprost reduces intraocular pressure in humans is by increasing aqueous humour outflow through the trabecular meshwork and enhancing uveoscleral outflow. Reduction of the intraocular pressure starts approximately 4 hours after the first administration and maximum effect is reached within approximately 8 to 12 hours. The duration of effect is maintained for at least 24 hours.

Bimatoprost is a potent ocular hypotensive agent. It is a synthetic prostamide, structurally related to prostaglandin F_2α (PGF_2α), that does not act through any known prostaglandin receptors. Bimatoprost selectively mimics the effects of newly discovered biosynthesised substances called prostamides. The prostamide receptor, however, has not yet been structurally identified.

Clinical efficacy

A 12 week (double-masked, randomized, parallel group ) clinical study compared the efficacy and safety of Bimagan 0.3 mg/mL single-dose with Bimagan 0.3 mg/mL (multi-dose formulation). Bimagan 0.3 mg/mL single-dose achieved non-inferior IOP-lowering efficacy to Bimagan 0.3 mg/mL (multi-dose formulation) for worse eye IOP change from baseline in patients with glaucoma or ocular hypertension. Bimagan 0.3 mg/mL single-dose also achieved equivalent IOP lowering efficacy with Bimagan 0.3 mg/mL (multi-dose formulation) in average eye IOP at each follow-up timepoint at weeks 2, 6 and 12.

During 12 months' monotherapy treatment with Bimagan 0.3 mg/mL (multi-dose formulation) in adults, versus timolol, mean change from baseline in morning (08:00) intraocular pressure ranged from -7.9 to -8.8 mmHg. At any visit, the mean diurnal IOP values measured over the 12-month study period differed by no more than 1.3 mmHg throughout the day and were never greater than 18.0 mmHg.

In a 6-month clinical study with Bimagan 0.3 mg/mL (multi-dose formulation), versus latanoprost, a statistically superior reduction in morning mean IOP (ranging from -7.6 to -8.2 mmHg for bimatoprost versus -6.0 to -7.2 mmHg for latanoprost) was observed at all visits throughout the study. Conjunctival hyperaemia, growth of eyelashes, and eye pruritus were statistically significantly higher with bimatoprost than with latanoprost, however, the discontinuation rates due to adverse events were low with no statistically significant difference.

Compared to treatment with beta-blocker alone, adjunctive therapy with beta-blocker and Bimagan 0.3 mg/mL (multi-dose formulation) lowered mean morning (08:00) intraocular pressure by -6.5 to -8.1 mmHg.

Limited experience is available in patients with open-angle glaucoma with pseudoexfoliative and pigmentary glaucoma, and chronic angle-closure glaucoma with patent iridotomy.

No clinically relevant effects on heart rate and blood pressure have been observed in clinical trials.

Paediatric population

The safety and efficacy of Bimagan in children aged 0 to 18 years has not been established.

Absorption

Bimatoprost penetrates the human cornea and sclera well in vitro. After ocular administration in adults, the systemic exposure of bimatoprost is very low with no accumulation over time. After once daily ocular administration of one drop of Bimagan 0.3 mg/mL to both eyes for two weeks, blood concentrations peaked within 10 minutes after dosing and declined to below the lower limit of detection (0.025 ng/ml) within 1.5 hours after dosing. Mean C_max and AUC _0-24hrs values were similar on days 7 and 14 at approximately 0.08 ng/ml and 0.09 ng-hr/ml respectively, indicating that a steady bimatoprost concentration was reached during the first week of ocular dosing.

Distribution

Bimatoprost is moderately distributed into body tissues and the systemic volume of distribution in humans at steady-state was 0.67 l/kg. In human blood, bimatoprost resides mainly in the plasma. The plasma protein binding of bimatoprost is approximately 88%.

Biotransformation

Bimatoprost is the major circulating species in the blood once it reaches the systemic circulation following ocular dosing. Bimatoprost then undergoes oxidation, N-deethylation and glucuronidation to form a diverse variety of metabolites.

Elimination

Bimatoprost is eliminated primarily by renal excretion, up to 67% of an intravenous dose administered to healthy adult volunteers was excreted in the urine, 25% of the dose was excreted via the faeces. The elimination half-life, determined after intravenous administration, was approximately 45 minutes; the total blood clearance was 1.5 l/hr/kg.

Characteristics in elderly patients

After twice daily dosing of Bimagan 0.3 mg/mL, the mean AUC_0-24hr value of 0.0634 ng-hr/ml bimatoprost in the elderly (subjects 65 years or older) were significantly higher than 0.0218 ng-hr/ml in young healthy adults. However, this finding is not clinically relevant as systemic exposure for both elderly and young subjects remained very low from ocular dosing. There was no accumulation of bimatoprost in the blood over time and the safety profile was similar in elderly and young patients.

Effects in non-clinical studies were observed only at exposures considered sufficiently in excess of the maximum human exposure indicating little relevance to clinical use.

Monkeys administered ocular bimatoprost concentrations of >0.3 mg/mL daily for 1 year had an increase in iris pigmentation and reversible dose-related periocular effects characterised by a prominent upper and/or lower sulcus and widening of the palpebral fissure. The increased iris pigmentation appears to be caused by increased stimulation of melanin production in melanocytes and not by an increase in melanocyte number. No functional or microscopic changes related to the periocular effects were observed, and the mechanism of action for the periocular changes is unknown.

Bimatoprost was not mutagenic or carcinogenic in a series of in vitro and in vivo studies.

Bimatoprost did not impair fertility in rats up to doses of 0.6 mg/kg/day (at least 103-times the intended human exposure). In embryo/foetal developmental studies abortion, but no developmental effects were seen in mice and rats at doses that were at least 860-times or 1700-times higher than the dose in humans, respectively. These doses resulted in systemic exposures of at least 33- or 97-times higher, respectively, than the intended human exposure. In rat peri/postnatal studies, maternal toxicity caused reduced gestation time, foetal death, and decreased pup body weights at >0.3 mg/kg/day (at least 41-times the intended human exposure). Neurobehavioural functions of offspring were not affected.

Not applicable.

No special requirements for disposal.