Findings from a recent study published in Ophthalmology measured the safety and intraocular pressure (IOP)-lowering efficacy of a fast-eluting (FE) and slow-eluting (SE) travoprost intraocular implant.
Give me some background first.
Medication nonadherence to topical IOP-lowering therapies is a pervasive issue for glaucoma patients due to a variety of factors, such as the inability to correctly instill eye drops and varying dosing schedules, among others.
In fact, nearly 50% of patients have been found to discontinue their initially prescribed IOP-lowering medications completely within 6 months; further, 90% intermittently fail to refill their prescriptions over a 3-year period.
Talk about the travoprost intraocular implant.
Consequently, sustained-release drug delivery systems are an emerging technology of interest for researchers and clinicians due to the potential for improved adherence.
The travoprost intraocular implant (iDose TR, Glaukos Corporation)—which recently launched in the United States—is a titanium implant reservoir with a membrane that controls the sustained release of a proprietary formulation of travoprost.
Two models of the implant have been developed, an FE- and SE- model, that differ in the thickness of the membrane (the SE-implant has a thicker membrane).
Are there previous studies on its efficacy?
A 3-year phase 2 clinical trial previously demonstrated that both models of the travoprost intraocular implant were well-tolerated and reduced topical IOP-lowering medication burden in a notable percentage of implant patients.
Currently, there are two phase 3 clinical trials (NCT03519386, NCT03868124) evaluating the efficacy and safety of both models of the implant.
This study presents the findings for the primary efficacy endpoint and safety of the implant through month 3 in the first of the two phase 3 trials.
Now talk about the study.
In this phase 3, multicenter, randomized, double-masked, sham-controlled, non-inferiority trial (NCT03519386), investigators randomized study eyes to receive an FE-implant (200 eyes) or SE-implant (197 eyes) with twice-daily (BID) placebo eye drops, or to sham procedure plus timolol ophthalmic solution 0.5% BID (193 eyes).
Researchers followed up with patients at day 10, week 6, and month 3 to measure IOP at 8 a.m. and 10 a.m. to monitor the IOP-lowering effect of the implant.
Talk about the cohort.
Participants were included in the study if they met the following criteria:
- Had open-angle glaucoma (OAG) or ocular hypertension (OHT)
- Used 0-3 IOP-lowering medications at screening
- Had an unmedicated baseline mean diurnal IOP of >21 mmHg (average of 8 a.m., 10 a.m., and 4 p.m.)
- Had an unmedicated baseline IOP of <36 mmHg at each time point in the study (i.e., 8 a.m., 10 a.m., and 4 p.m.)
What were the main outcome measures?
The primary outcome measure was the mean change from baseline IOP in the study eye at 8 a.m. and 10 a.m. on day 10, week 6, and month 3.
Safety outcomes included:
- Adverse events (AEs)
- Corneal endothelial cell counts
- Visual acuity (VA)
- Conjunctival hyperemia assessment
Findings?
The mean IOP reduction from baseline over the six time points (i.e., 8 a.m. and 10 a.m. on day 10, week 6, and month 3) for each group was as follows:
- FE-implant: 6.6-8.4 mmHg
- SE-implant: 6.6-8.5 mmHg
- Timolol: 6.5-7.7 mmHg
The primary efficacy endpoint was met and the upper limit of the 95% confidence interval (CI) of the difference between the implant groups and the timolol group was < 1 mmHg at all six timepoints.
What about adverse events?
Most of the study eye AEs were mild or moderate in severity and were reported in 21.5%, 27.2%, and 10.8% of subjects in the FE-implant, SE-implant, and timolol groups, respectively.
One study eye with an AE of endophthalmitis was reported.
The most common AEs included:
- Iritis (FE-implant 0.5%, SE-implant 5.1%)
- Ocular hyperemia (FE-implant 3.0%, SE-implant 2.6%)
- Reduced VA (FE-implant 1.0%, SE-implant 4.1%, timolol 0.5%)
- Increased IOP (FE-implant 3.5%, SE-implant 2.6%, timolol 2.1%)
Take home.
The travoprost intraocular implant demonstrated robust IOP reduction over the 3-month primary efficacy evaluation period following a single administration.
The IOP-lowering efficacy of both the SE- and FE-implant groups were statistically and clinically non-inferior to the timolol group, with a favorable safety profile.
And the conclusion …
This travoprost implant could be a safe and effective alternative to topical IOP-lowering medications for glaucoma patients who struggle with medication nonadherence.