A multicenter, randomized, double-masked, placebo-controlled phase 3 study has demonstrated the efficacy and safety of a dexamethasone intracanalicular insert (DEXTENZA, Ocular Therapeutix, Inc.) for treating allergic conjunctivitis. The study, involving 96 subjects, evaluated the insert's ability to alleviate the signs and symptoms of allergic conjunctivitis using a modified conjunctival allergen challenge (CAC) model.
Primary Endpoint Achieved
The primary endpoint, subject-evaluated ocular itching on Day 8, was met with statistically significant treatment differences (P < 0.0001) favoring the dexamethasone insert group at 3, 5, and 7 minutes post-CAC. Specifically, the dexamethasone insert group showed reductions of -0.86, -0.98, and -0.96 units at 3, 5, and 7 minutes, respectively, compared to the placebo group.
Secondary Endpoints Demonstrate Broad Symptom Relief
Key secondary efficacy endpoints, including ocular itching at various time points and investigator-evaluated conjunctival redness, also showed statistically significant improvements. The dexamethasone insert group exhibited lower ocular itching scores at 23 of 24 study time points (P < 0.05). Conjunctival redness was significantly reduced across all 18 time points (P < 0.05), with treatment differences ≥0.5 units favoring the dexamethasone group after Day 7 (P < 0.0005).
Additional secondary endpoints, such as ciliary and episcleral redness, eyelid swelling, tearing/watery eyes, rhinorrhea, nasal pruritus, ear or palate pruritus, and nasal congestion, generally favored the dexamethasone insert group, indicating a comprehensive reduction in allergic conjunctivitis symptoms.
Favorable Safety Profile
The dexamethasone insert demonstrated a favorable safety profile, with no serious adverse events (SAEs) reported. Of the 96 subjects in the safety population, 23 reported a total of 30 AEs, with fewer AEs reported in the dexamethasone insert group (9 subjects) compared to the placebo group (14 subjects). All AEs were mild or moderate in severity, and most were not considered related to the study treatment. Two subjects in the dexamethasone insert group experienced ocular AEs (eye discharge and eye irritation), both considered related to treatment. No subjects experienced elevated intraocular pressure (IOP) or worsening of visual acuity.
Clinical Implications
The study results support the potential use of dexamethasone as a sustained-release, physician-administered therapy for allergic conjunctivitis. The insert's efficacy in reducing both ocular itching and conjunctival redness, coupled with its favorable safety profile, suggests it could be a valuable alternative to traditional eye drops. Unlike eye drops, the dexamethasone insert is physician-administered, eliminating concerns about patient compliance and overuse. It is also preservative-free, reducing the risk of ocular surface toxicity associated with preservatives like benzalkonium chloride (BAK).
Addressing Unmet Needs in Allergic Conjunctivitis Treatment
Allergic conjunctivitis affects a significant portion of the US population, often leading to a reduced quality of life. Current treatments include topical antihistamines and mast-cell stabilizers, which have limitations such as short duration of action or long loading periods. Topical corticosteroids are effective but are typically limited to short-term use due to potential complications. The dexamethasone insert offers a sustained-release, preservative-free option that can address these limitations and improve patient outcomes.
