Effect of preservative removal from fixed-combination bimatoprost/timolol on intraocular pressure lowering: a potential timolol dose–response phenomenon

Jie Shen,1 Marina Bejanian2 1Department of Translational Sciences, 2Department of Ophthalmology Clinical Development, Allergan plc, Irvine, CA, USA Purpose: Many patients with glaucoma require combination therapies to achieve target intraocular pressure (IOP) and preserve visual function. Ocular hypotensives often contain a preservative (eg, benzalkonium chloride [BAK]), but preservative-free (PF) formulations have been developed for patients with sensitivity. A Phase III study found the efficacy of bimatoprost 0.03%/timolol 0.5% (bim/tim, Ganfort®) PF to be equivalent to that of preserved bim/tim, although a trend favoring bim/tim PF was observed. As BAK is a corneal penetration enhancer, this literature review aims to explain these findings by exploring the relationship between timolol concentration and its IOP-lowering effect. Methods: Systematic searches were performed in Scopus and PubMed for clinical trials published in English between 1960 and July 2014 using the keywords “timolol”, “intraocular pressure”, and the concentrations “1%, 0.5%, OR 0.25%”. Articles that directly compared IOP-lowering effects of ≥2 concentrations of timolol were identified by manual screening, and cross-checked for duplication. Results: Seventeen studies that included 10–371 patients were evaluated; the majority were randomized (16/17), double-masked (14/17), and enrolled patients with open-angle glaucoma or ocular hypertension (12/17). All studies investigated timolol in preserved formulations. Timolol concentrations tested ranged from 0.008% to 1.5%. Of 13 studies comparing timolol 0.25% versus 0.5%, two found the 0.25% dose to have greater IOP-lowering effects, and three reported the opposite; eight reported similar IOP lowering. Results also indicate that timolol 0.5% may be more effective than higher concentrations. Conclusion: The evidence suggests that timolol may have an inverted U-shaped dose–response curve, and that its optimal IOP-lowering concentration is between 0.25% and 0.5%. Compared with bim/tim, removal of the permeability enhancer BAK in bim/tim PF could have resulted in a lower timolol concentration at the target site, bringing the effective concentration within the 0.25%–0.5% range and enhancing the efficacy of bim/tim PF. Keywords: glaucoma, intraocular pressure, timolol, bimatoprost, preservative, dose–respons

Intracameral Sustained-Release Bimatoprost Implant Delivers Bimatoprost to Target Tissues with Reduced Drug Exposure to Off-Target Tissues.

PURPOSE: To explore the ocular distribution of bimatoprost after intracameral administration of a biodegradable sustained-release bimatoprost implant (Bimatoprost SR) versus repeated topical administration of bimatoprost 0.03% ophthalmic solution in dogs. Bimatoprost SR and topical bimatoprost 0.03% previously were shown to have similar intraocular pressure-lowering effects in humans in a phase 1/2 clinical trial. METHODS: Twenty-four beagle dogs received either once-daily topical bimatoprost 0.03% for 7 days or a bilateral intracameral administration of Bimatoprost SR (15 μg). At predetermined time points, ocular tissues were collected and concentrations of bimatoprost and bimatoprost acid were quantified using liquid chromatography-tandem mass spectrometry. RESULTS: Bimatoprost SR administration enhanced delivery of study drug to a site of action [iris-ciliary body (ICB)] compared with topical bimatoprost (Cmax [bimatoprost+bimatoprost acid] = 18,200 and 4.13 ng/g, respectively). However, distribution of drug to tissues associated with prostaglandin analog (PGA)-related side effects (i.e., bulbar conjunctiva, eyelid margins, and periorbital fat) was limited following Bimatoprost SR administration (Cmax [bimatoprost+bimatoprost acid] = BLQ [beneath the limit of quantitation] to 0.354 ng/g) compared with topical dosing (Cmax [bimatoprost+bimatoprost acid] = 36.6-2,110 ng/g). CONCLUSIONS: Bimatoprost SR administration in dogs selectively delivered drug to the ICB with low or undetectable drug levels in ocular surface and extraocular tissues. Use of Bimatoprost SR for glaucoma treatment may reduce the incidence of adverse events typically associated with topical PGAs by targeting bimatoprost delivery to the key site of action of the PGA class and reducing exposure to off-target tissues

ABBREVIATIONS: PCP,phencyclidine; 3-PPP,(+)-3-(3-hydroxyphenyl)-N-(1-propyl)pipendine;(+)-SKF, (+)SKF 10,047;ANOVA,analysis of variance

ABSTRACT The current study investigated the effects of acute and chronic administration of (+)-SKF 10,047 on body temperature in rats. The effect of phencyclidine on body temperature in chronically (+)-SKF 10,047-treated rats was also investigated. The acute administration of (+)-SKF 10,047 at doses of 5 to 40 mg/kg s.c. did not alter body temperature; however, 80 mg/kg produced hypothermia. In contrast, chronic administration of (+)-SKF 10,047 (5â€"20mg/kg) produced dose-dependent hyperthermia when tested on day 7 and 10 of chronic treatment. Moreover, sensitization to the hyperthermic effects occurred as the degree of hyperthermia was greater on day 10 compared to day 7. Phencyclidine (20 mg/kg s.c.) produced hypothermia in rats chronically treated with saline for 13 days, but hyperthermia in rats chronically treated with 20 mg/kg of (+)-SKF 10,047 for the same duration. The hyperthermic effect of chronic (+)-SKF 10,047 treatment is similar to the previously reported dose dependent hyperthermia in chronically phencyclidine-treated an imals. The cross-sensitization of chronically (+)-SKF 10,047-treated rats to the hyperthermic effects of phencyclidinesupports the hypothesis that there may be common mechanisms under lying the chronic effects of these drugs on body temperature

Efficacy of a preservative-free formulation of fixed-combination bimatoprost and timolol (Ganfort PF) in treatment-naïve patients vs previously treated patients

M Francesca Cordeiro,1 Ivan Goldberg,2 Rhett Schiffman,3 Paula Bernstein,3 Marina Bejanian31Western Eye Hospital, Imperial College Healthcare NHS Trust, London, UK; 2Discipline of Ophthalmology, University of Sydney, Sydney, NSW, Australia; 3Allergan, Inc., Irvine, CA, USAPurpose: To evaluate, using subgroup analysis, the effect of treatment status on the intraocular pressure (IOP)-lowering efficacy of a preservative-free formulation of fixed-combination bimatoprost 0.03%/timolol 0.5% (FCBT PF).Methods: A primary, multicenter, randomized, double-masked, 12-week study compared the efficacy and safety of FCBT PF with preserved FCBT (Ganfort®) in 561 patients diagnosed with glaucoma or ocular hypertension. For this analysis, eligible patients were treatment-naïve or had inadequate IOP lowering and underwent a washout of previous treatment. IOP (8 am, 10 am, and 4 pm) was measured at baseline and weeks 2, 6, and 12. Subgroup analysis of the FCBT PF arm assessed changes in average eye IOP from baseline in treatment-naïve vs previously treated patients. To evaluate the effect of treatment status at baseline (treatment-naïve vs previously treated) on IOP reduction in the FCBT PF treatment group, an analysis of covariance model was used with treatment status and investigator as fixed effects, and baseline average eye IOP, age, glaucoma diagnosis, and baseline average eye corneal thickness as covariates. P-values and the 95% confidence intervals were determined using the model.Results: In the FCBT PF arm, IOP mean changes from baseline ranged from -8.7 mmHg to -9.8 mmHg in treatment-naïve patients (N=50), compared with -7.3 mmHg to -8.5 mmHg in previously treated patients (N=228). Baseline IOP, age, glaucoma diagnosis, and corneal thickness significantly affected IOP reduction in the FCBT PF group. Adjusting for these covariates, FCBT PF had a greater IOP-lowering effect (0.8–1.7 mmHg) in treatment-naïve patients than previously treated patients, which was statistically significant (P≤0.05) at seven of nine time points.Conclusion: In this subgroup analysis, FCBT PF reduced IOP more effectively in treatment-naïve than in previously treated patients possibly due, in part, to altered responsiveness or tachyphylaxis that has been associated with prior ocular hypotensive agent treatment.Keywords: glaucoma, ocular hypertension, intraocular pressure, bimatoprost, timolol, benzalkonium chlorid

Phase 3, Randomized, 20-Month Study of Bimatoprost Implant in Open-Angle Glaucoma and Ocular Hypertension (ARTEMIS 1).

PURPOSE: To evaluate the intraocular pressure (IOP)-lowering efficacy and safety of 10- and 15-μg bimatoprost implant in subjects with open-angle glaucoma (OAG) and ocular hypertension (OHT) after initial and repeated administrations. DESIGN: Randomized, 20-month, multicenter, subject- and efficacy evaluator-masked, parallel-group, phase 3 clinical study. PARTICIPANTS: Adults with OAG or OHT in each eye, open iridocorneal angle inferiorly in the study eye, and study eye baseline IOP (hour 0; 8 am) of 22-32 mmHg after washout. METHODS: Study eyes received bimatoprost implant 10 μg (n = 198) or 15 μg (n = 198) on day 1 with readministration at weeks 16 and 32, or twice-daily topical timolol maleate 0.5% (n = 198). Intraocular pressure was measured at hours 0 and 2 at each visit. MAIN OUTCOME MEASURES: Primary end points were IOP and change from baseline IOP through week 12. Safety measures included treatment-emergent adverse events (TEAEs) and corneal endothelial cell density (CECD). RESULTS: Both dose strengths of bimatoprost implant were noninferior to timolol in IOP lowering after each administration. Mean diurnal IOP was 24.0, 24.2, and 23.9 mmHg at baseline and from 16.5-17.2, 16.5-17.0, and 17.1-17.5 mmHg through week 12 in the 10-μg implant, 15-μg implant, and timolol groups, respectively. The incidence of corneal and inflammatory TEAEs of interest (e.g., corneal endothelial cell loss, iritis) was higher with bimatoprost implant than timolol and highest with the 15-μg dose strength. Incidence of corneal TEAEs increased after repeated treatment; with 3 administrations at fixed 16-week intervals, incidence of ≥20% CECD loss was 10.2% (10-μg implant) and 21.8% (15-μg implant). Mean best-corrected visual acuity (BCVA) was stable; 3 implant-treated subjects with corneal TEAEs had >2-line BCVA loss at their last visit. CONCLUSIONS: Both dose strengths of bimatoprost implant met the primary end point of noninferiority to timolol through week 12. One year after 3 administrations, IOP was controlled in most subjects without additional treatment. The risk-benefit assessment favored the 10-μg implant over the 15-μg implant. Ongoing studies are evaluating other administration regimens to reduce the potential for CECD loss. The bimatoprost implant has potential to improve adherence and reduce treatment burden in glaucoma

Efficacy of a preservative-free formulation of fixed-combination bimatoprost and timolol (Ganfort PF) in treatment-naive patients vs previously treated patients

Purpose: To evaluate, using subgroup analysis, the effect of treatment status on the intraocular pressure (IOP)-lowering efficacy of a preservative-free formulation of fixed-combination bimatoprost 0.03%/timolol 0.5% (FCBT PF). Methods: A primary, multicenter, randomized, double-masked, 12-week study compared the efficacy and safety of FCBT PF with preserved FCBT (Ganfort®) in 561 patients diagnosed with glaucoma or ocular hypertension. For this analysis, eligible patients were treatment-naïve or had inadequate IOP lowering and underwent a washout of previous treatment. IOP (8 am, 10 am, and 4 pm) was measured at baseline and weeks 2, 6, and 12. Subgroup analysis of the FCBT PF arm assessed changes in average eye IOP from baseline in treatment-naïve vs previously treated patients. To evaluate the effect of treatment status at baseline (treatment-naïve vs previously treated) on IOP reduction in the FCBT PF treatment group, an analysis of covariance model was used with treatment status and investigator as fixed effects, and baseline average eye IOP, age, glaucoma diagnosis, and baseline average eye corneal thickness as covariates. P-values and the 95% confidence intervals were determined using the model. Results: In the FCBT PF arm, IOP mean changes from baseline ranged from -8.7 mmHg to -9.8 mmHg in treatment-naïve patients (N=50), compared with -7.3 mmHg to -8.5 mmHg in previously treated patients (N=228). Baseline IOP, age, glaucoma diagnosis, and corneal thickness significantly affected IOP reduction in the FCBT PF group. Adjusting for these covariates, FCBT PF had a greater IOP-lowering effect (0.8–1.7 mmHg) in treatment-naïve patients than previously treated patients, which was statistically significant (P≤0.05) at seven of nine time points. Conclusion: In this subgroup analysis, FCBT PF reduced IOP more effectively in treatment-naïve than in previously treated patients possibly due, in part, to altered responsiveness or tachyphylaxis that has been associated with prior ocular hypotensive agent treatment

24-Month Phase I/II Clinical Trial of Bimatoprost Sustained-Release Implant (Bimatoprost SR) in Glaucoma Patients.

OBJECTIVE: The objective of this study was to evaluate the safety and intraocular pressure (IOP)-lowering effects over 24 months of biodegradable bimatoprost sustained-release implant (Bimatoprost SR) administration versus topical bimatoprost 0.03% in patients with open-angle glaucoma (OAG). METHODS: This was a phase I/II, prospective, 24-month, dose-ranging, paired-eye controlled clinical trial. At baseline following washout, adult patients with OAG (N = 75) received Bimatoprost SR (6, 10, 15, or 20 µg) intracamerally in the study eye; the fellow eye received topical bimatoprost 0.03% once daily. Rescue topical IOP-lowering medication or single repeat administration with implant was permitted. The primary endpoint was IOP change from baseline. Safety measures included adverse events (AEs). RESULTS: At month 24, mean IOP reduction from baseline was 7.5, 7.3, 7.3, and 8.9 mmHg in eyes treated with Bimatoprost SR 6, 10, 15, and 20 µg, respectively, versus 8.2 mmHg in pooled fellow eyes; 68, 40, and 28% of pooled study eyes had not been rescued/retreated at months 6, 12, and 24, respectively. AEs in study eyes that occurred ≤ 2 days post-procedure typically were transient. After 2 days post-procedure, overall AE incidence was similar between study and fellow eyes, with some events typically associated with topical prostaglandin analogs having lower incidence in study eyes. CONCLUSIONS: Bimatoprost SR showed favorable efficacy and safety profiles up to 24 months, with all evaluated dose strengths demonstrating overall IOP-reducing effects comparable to those of topical bimatoprost. Targeted and sustained delivery of bimatoprost resulted in protracted IOP lowering, suggesting that Bimatoprost SR may represent a transformational new approach to glaucoma therapy. Clinicaltrials.gov identifier: NCT01157364