Ocular pharmacokinetics and tolerability of bimatoprost ophthalmic solutions administered once or twice daily in rabbits, and clinical dosing implications

From Eye Care to Hair Growth: Bimatoprost

BACKGROUND

Bimatoprost has emerged as a significant medication in the field of medicine over the past several decades, with diverse applications in ophthalmology, dermatology, and beyond. Originally developed as an ocular hypotensive agent, it has proven highly effective in treating glaucoma and ocular hypertension. Its ability to reduce intraocular pressure has established it as a first-line treatment option, improving management and preventing vision loss. In dermatology, bimatoprost has shown promising results in the promotion of hair growth, particularly in the treatment of alopecia and hypotrichosis. Its mechanism of action, stimulating the hair cycle and prolonging the growth phase, has led to the development of bimatoprost-containing solutions for enhancing eyelash growth.

AIM

The aim of our review is to provide a brief description, overview, and studies in the current literature regarding the versatile clinical use of bimatoprost in recent years. This can help clinicians determine the most suitable individualized therapy to meet the needs of each patient.

METHODS

Our methods involve a comprehensive review of the latest advancements reported in the literature in bimatoprost formulations, which range from traditional eye drops to sustained-release implants. These innovations offer extended drug delivery, enhance patient compliance, and minimize side effects.

RESULTS

The vast literature published on PubMed has confirmed the clinical usefulness of bimatoprost in lowering intraocular pressure and in managing patients with glaucoma. Numerous studies have shown promising results in dermatology and esthetics in promoting hair growth, particularly in treating alopecia and hypotrichosis. Its mechanism of action involves stimulating the hair cycle and prolonging the growth phase, leading to the development of solutions that enhance eyelash growth. The global use of bimatoprost has expanded significantly, with applications growing beyond its initial indications. Ongoing research is exploring its potential in glaucoma surgery, neuroprotection, and cosmetic procedures.

CONCLUSIONS

Bimatoprost has shown immense potential for addressing a wide range of therapeutic needs through various formulations and advancements. Promising future perspectives include the exploration of novel delivery systems such as contact lenses and microneedles to further enhance drug efficacy and patient comfort. Ongoing research and future perspectives continue to shape its role in medicine, promising further advancements and improved patient outcomes.

Triple Fixed-Combination Bimatoprost/Brimonidine/Timolol in Glaucoma and Ocular Hypertension in India: A Multicenter, Open-Label, Phase 3 Study

Introduction

To evaluate the intraocular pressure (IOP)-lowering efficacy and safety of a triple fixed-combination of bimatoprost, brimonidine, and timolol (TFC) in patients with glaucoma or ocular hypertension (OHT) treated with fixed-combination or unfixed brimonidine and timolol therapy (dual-combination therapy).

Methods

In this multicenter, open-label, phase 3 study, patients who received 4-8 weeks of dual-combination therapy twice daily and had an IOP >18 and <34 mmHg in at least one eye were switched (at baseline) to treatment with TFC twice daily for 12 weeks. At Weeks 4, 8, and 12 on TFC, IOP was assessed at Hours 0, 2, and 8. Primary efficacy variable: mean diurnal IOP change from baseline in the study eye at Week 12 (modified intent-to-treat [mITT] population). Sensitivity (per-protocol [PP] population) and subgroup (≤65 vs >65 years) analyses were performed. Safety, including adverse events (AEs), was assessed at each visit.

Results

Of 126 patients enrolled, 121 and 103 formed the mITT/safety and PP populations, including 109 (90.1%) and 94 (91.3%) who completed the study, respectively. In the mITT/safety population, mean age was 58.6 years. Patients had open-angle glaucoma (51.2%), angle-closure glaucoma with patent iridotomy (36.4%), and/or OHT (13.2%). At Week 12, the mean diurnal change in IOP from dual combination-treated baseline was statistically significant (P<0.001) with TFC in the mITT (-3.98 mmHg) and PP (-4.22 mmHg) populations. Results were similar at all visits, regardless of the age subgroup. The most frequent treatment-related AEs were conjunctival hyperemia (14.0%) and dry eye (4.1%); 5.8% of the patients discontinued treatment due to ocular AEs.

Conclusion

TFC offers a beneficial therapeutic alternative for patients with glaucoma or OHT whose IOP is not sufficiently controlled with dual-combination therapy. Safety and efficacy findings support those of published studies of TFC in primary open-angle glaucoma and OHT, despite differences in study designs.

Extraocular, periocular, and intraocular routes for sustained drug delivery for glaucoma

Although once daily anti-glaucoma drug therapy is a current clinical reality, most therapies require multiple dosing and there is an unmet need to develop convenient, safe, and effective sustained release drug delivery systems for long-term treatment to improve patient adherence and outcomes. One of the first sustained release drug delivery systems was approved for the reduction of intraocular pressure in glaucoma patients. It is a polymeric reservoir-type insert delivery system, Ocusert™, placed under the eyelid and on the ocular surface for zero-order drug release over one week. The insert, marketed in two strengths, released pilocarpine on the eye surface. While many clinicians appreciated this drug product, it was eventually discontinued. No similar sustained release non-invasive drug delivery system has made it to the market to date for treating glaucoma. Drug delivery systems under development include punctal plugs, ring-type systems, contact lenses, implants, microspheres, nanospheres, gels, and other depot systems placed in the extraocular, periocular, or intraocular regions including intracameral, supraciliary, and intravitreal spaces. This article discusses the advantages and disadvantages of the various routes of administration and delivery systems for sustained glaucoma therapy. It also provides the reader with some examples and discussion of drug delivery systems that could potentially be applied for glaucoma treatment. Interestingly, one intracamerally injected implant, Durysta™, was approved recently for sustained intraocular pressure reduction. However, long-term acceptance of such devices has yet to be established. The ultimate success of the delivery system will depend on efficacy relative to eye drop dosing, safety, reimbursement options, and patient acceptance. Cautious development efforts are warranted considering prior failed approaches for sustained glaucoma drug delivery. Neuroprotective approaches for glaucoma therapy including cell, gene, protein, and drug-combination therapies, mostly administered intravitreally, are also rapidly progressing towards assessment in humans.

Fixed-combination Bimatoprost/Brimonidine/Timolol in Glaucoma: A Randomized, Masked, Controlled, Phase III Study Conducted in Brazil☆

PURPOSE

Many patients with open-angle glaucoma eventually require >2 medications to lower their intraocular pressure (IOP). Fixed-combination ophthalmic solutions can be advantageous in patients who require multiple medications, but the number of fixed combinations combining 3 complementary IOP-lowering agents remains limited. This study assessed the efficacy and safety of a triple fixed combination (TFC) of bimatoprost 0.01%/brimonidine 0.15%/timolol 0.5% ophthalmic solution in patients with primary open-angle glaucoma (POAG) or ocular hypertension (OHT), compared with a dual fixed combination (DFC) of brimonidine 0.2%/timolol 0.5%.

METHODS

Patients with a baseline IOP of 23-34 mm Hg in both eyes and no history of IOP-lowering procedures were eligible for participation in this multicenter, double-masked, randomized, Phase III study. After washout of previous treatment (if applicable), patients were randomized to receive TFC or DFC twice daily in each eye for 3 months. The primary efficacy variable was the change from baseline in mean IOP in the worse eye at week 12 in the modified intent-to-treat (mITT) population. TFC was superior to DFC if the treatment difference (TFC - DFC) favored TFC at week 12 (P ≤ 0.05; 2-sample t test). Secondary and sensitivity analyses were also performed. Safety, including adverse events, was assessed at all visits.

FINDINGS

The mITT/safety population included 185 patients (TFC, n = 90; DFC, n = 95). TFC superiority was demonstrated at all postbaseline visits (all, P < 0.001) through week 12 (week 12 treatment difference: ─2.17 mm Hg; 95% CI, ─3.12 to ─1.22). While treatment-related conjunctival hyperemia was more frequent with TFC than with DFC (47.8% vs 23.2%; P < 0.001), consistent with the additional presence of bimatoprost in TFC, most cases were mild and the numbers of patient discontinuations at week 12 were similar between the TFC and DFC groups (11 [12.2%] vs 7 [7.4%] patients; P = 0.266). No unexpected adverse events were reported.

IMPLICATIONS

Compared with DFC, TFC provided superior IOP lowering throughout the primary efficacy period. An acceptable tolerability profile was observed through 12 months of use of TFC, offering an effective therapeutic option in patients with POAG or OHT who require multiple medications to control their IOP. Additional studies are required for the assessment of the long-term effects of TFC. ClinicalTrials.gov identifier: NCT01217606.

Dose-Response of Intracameral Bimatoprost Sustained-Release Implant and Topical Bimatoprost in Lowering Intraocular Pressure

Purpose: To compare the dose–response profiles of bimatoprost sustained-release implant (Bimatoprost SR) and topical bimatoprost in lowering intraocular pressure (IOP) in normotensive beagle dogs.

Methods: In 1 study, topical bimatoprost 0.001%, 0.01%, or 0.1% was administered twice daily in the study eye for 5 days. IOP was measured at baseline and up to hour 6 each day. Other studies evaluated the IOP response to a single administration of Bimatoprost SR at dose strengths ranging from 8 to 120 μg. IOP was measured before implant administration and during 3 months of follow-up; IOP in response to topical bimatoprost 0.03% was measured prestudy as an internal control.

Results: Mean percentage decrease in IOP from baseline at hour 6 (peak effect) across study days was 15.7%, 36.1%, and 24.8% (2.8, 7.0, and 4.0 mmHg) in animals treated with topical bimatoprost 0.001%, 0.01%, and 0.1%, respectively. After Bimatoprost SR administration, mean percentage decrease in IOP from baseline across 3 months consistently increased with increasing dose strength and was 38.7% (7.2 mmHg) with Bimatoprost SR 120 μg. Mean percentage IOP decrease with topical bimatoprost 0.03% was 27.6% (5.9 mmHg).

Conclusions: Topical bimatoprost demonstrated a U-shaped dose–response curve; increasing the bimatoprost concentration to 0.1% resulted in reduced IOP-lowering efficacy. In contrast, the dose–response curve for Bimatoprost SR showed consistently greater IOP lowering as the dose strength increased, with the dose strength producing maximum IOP lowering not yet determined. At 60- and 120-μg dose strengths, Bimatoprost SR produced greater IOP reductions than were achieved with topical dosing.