Managing Dry Eye Disease with Novel Medications: Mechanism, Study Validity, Safety, Efficacy, and Practical Application

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TL;DR

This review of five FDA-approved novel medications for dry eye disease (lifitegrast, cyclosporine 0.09%, loteprednol etabonate, perfluorohexyloctane, and varenicline nasal spray) found them to be safe and efficacious with minimal side effects, based on robust randomized controlled trials with predominantly low bias. Cyclosporine and loteprednol are effective when artificial tears fail, perfluorohexyloctane reduces tear evaporation and is preservative-free, and varenicline offers a nasal route ideal for contact lens users. These medications provide alternative treatment options for patients whose dry eye is not managed by current therapies.

Full summary

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**Background:** Dry eye disease (DED) is a common condition characterized by reduced tear production and increased tear evaporation, leading to symptoms such as burning, irritation, tearing, and blurry vision. It affects mainly older individuals and women, with an estimated 4.88 million individuals over 50 in the U.S. experiencing DED. The 2018 AAO guidelines recommend a stepwise approach, starting with environmental modifications and artificial tears, and progressing to prescription drugs. This review examines five novel FDA-approved medications for DED: lifitegrast, cyclosporine 0.09%, loteprednol etabonate, perfluorohexyloctane, and varenicline nasal spray, focusing on their mechanisms, study outcomes, safety, efficacy, and trial validity.

**Methods:** A PubMed search was conducted using keywords "dry eye disease", "lifitegrast", "cyclosporine", "loteprednol etabonate", "varenicline", and "perfluorohexyloctane" to identify landmark trials leading to FDA approval. Filters included randomized controlled trials (RCTs), publication dates from 1 January 2015 to 5 June 2023, human studies, and English language. The search yielded 920 results, with seven trials deemed important. Trial validity was assessed using the FRISBE mnemonic (follow-up, randomization, intent-to-treat analysis, similar baseline characteristics, blinding, equal treatment).

**Key Results:** - **Lifitegrast 5% (Xiidra):** In a phase 3 RCT with 718 participants (358 lifitegrast, 360 placebo), lifitegrast showed statistically significant improvement in eye dryness score (EDS) (p < 0.0001) but no difference in inferior corneal fluorescein staining (iCFS) (p = 0.6186). Secondary endpoints showed significant improvements in eye discomfort (p < 0.0001) and ocular discomfort (p = 0.0005). Ocular treatment-emergent adverse events (TEAEs) occurred in 33.7% of the lifitegrast group vs. 16.4% in placebo. - **Cyclosporine 0.09% (Cequa):** A phase 3 RCT with 744 patients (371 cyclosporine, 373 vehicle) found a statistically significant difference in ≥10 mm changes in Schirmer test scores (STS) favoring cyclosporine (p < 0.001). The drug was well-tolerated with mild TEAEs. - **Loteprednol etabonate 0.25% (Eysuvis):** Three phase 3 trials (STRIDE 1, 2, 3) with approximately 2800 participants showed a more noticeable reduction in conjunctival hyperemia with loteprednol vs. vehicle. Ocular discomfort was significantly reduced in STRIDE 1 and 3. The most common adverse event was instillation site pain (<5.5%). - **Perfluorohexyloctane (Miebo):** The GOBI study (597 patients: 303 perfluorohexyloctane, 294 saline) showed statistically significant improvement in total corneal fluorescein staining (tCFS) and EDS (p < 0.001) and all secondary endpoints (p < 0.01). Mild ocular AEs occurred in 9.6% of the perfluorohexyloctane group vs. 7.5% in saline. The MOJAVE study (same sample size) confirmed significant improvements in tCFS and EDS (p < 0.001) and secondary endpoints (p < 0.01). - **Varenicline nasal spray (Tyrvaya):** ONSET-1 (182 patients: 139 varenicline, 43 vehicle) showed clinically significant improvement in tear film production with 0.03 mg or 0.06 mg doses (p < 0.001) and reduction in EDS with 0.03 mg (p = 0.021). TEAEs occurred in 70–93% of varenicline groups vs. 26% in vehicle. ONSET-2 (758 patients: 506 varenicline, 252 vehicle) found 47.3% (0.03 mg) and 49.2% (0.06 mg) achieved ≥10 mm change in STS. EDS difference was not clinically significant. TEAEs occurred in 86.5% of subjects.

Validity assessment using FRISBE revealed low risk of bias with minor concerns regarding poor follow-up and moderate drop-out rates; all RCTs were considered to have high validity.

**Clinical Implications:** These novel medications offer alternative treatment options for DED patients not managed by current therapies. Cyclosporine 0.09% provides higher bioavailability than cyclosporine 0.05% and may improve corneal staining and tear production. Loteprednol etabonate is effective for short-term use (up to two weeks) and may benefit patients refractory to cyclosporine. Perfluorohexyloctane directly targets tear evaporation and is preservative-free, making it suitable for evaporative dry eye and patients with preservative sensitivity. Varenicline nasal spray avoids ocular discomfort and is ideal for contact lens users and patients with conditions like glaucoma or arthritis. The review notes that no head-to-head trials exist, and combination therapy benefits are unknown. Further research is needed on long-term outcomes, efficacy comparisons, and use in special populations.