Topical cyclosporine A therapy for dry eye syndrome

Topical cyclosporine A (also known as ciclosporin A) (CsA) is an anti-inflammatory that has been widely used to treat inflammatory ocular surface diseases. Two CsA eyedrops have been approved by US Food and Drug Administration for managing dry eye: Restasis (CsA 0.05%, Allergan Inc, Irvine, CA, USA), approved in 2002, and Cequa (CsA 0.09%, Sun Pharma, Cranbury, NJ, USA), approved in 2018. Numerous clinical trials have been performed to assess the effectiveness and safety of CsA for dry eye; however, there is no universal consensus with regard to its effect.

To assess the effectiveness and safety of topical CsA in the treatment of dry eye.

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2018, Issue 2); Ovid MEDLINE; Embase.com; PubMed; Latin American and Caribbean Health Sciences Literature Database (LILACS); ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We did not use any date or language restrictions in the electronic search for trials. We last searched the electronic databases on 16 February 2018.

We included randomized controlled trials (RCTs) of people with dry eye regardless of age, sex, severity, etiology, or classification of dry eye. We included RCTs in which different concentrations of topical CsA were compared with one another or with artificial tears, placebo, or vehicle. We also included RCTs in which CsA in combination with artificial tears was compared to artificial tears alone.

We followed the standard Cochrane methodology and assessed the certainty of the evidence using GRADE.

We included 30 RCTs (4009 participants) with follow-up periods ranging from 6 weeks to 12 months. We studied dry eye of various severity and underlying causes. The interventions investigated also varied across RCTs: CsA versus artificial tears; CsA with artificial tears versus artificial tears alone; and in some studies, more than one concentration of CsA. Artificial tears were used as adjunctive to study medication in all but five trials. Almost all trials had deficiencies in the reporting of results (e.g. reporting P values or direction only), precluding the calculation of between-group estimates of effect or meta-analysis.Eighteen trials compared topical CsA 0.05% plus artificial tears versus vehicle plus artificial tears or artificial tears alone. One trial reported subjective symptoms of dry eye at 6 months and the results were in favor of CsA (mean difference (MD) -4.80, 95% confidence interval (CI) -6.41 to -3.19; low-certainty evidence). Two trials reported MD in ocular surface dye staining at 6 months, but the results were inconsistent in these two trials (MD -0.35, 95% CI -0.69 to -0.01 in one and MD 0.58, 95% CI 0.06 to 1.10 in the other; low-certainty evidence). Four trials reported MD in Schirmer test scores at 6 months and the estimates ranged from -4.05 (95% CI -6.67 to -1.73) to 3.26 (95% CI -1.52 to 5.00) (low-certainty evidence). Three trials reported risk ratio (RR) of improved Schirmer test scores at 6 months; estimates ranged from 0.98 (95% CI 0.83 to 1.17) to 3.50 (95% CI 2.09 to 5.85) (low-certainty evidence). Four trials reported MD in tear film stability measured by tear break-up time at 6 months and the estimates ranged from -1.98 (95% CI -3.59 to -0.37) to 1.90 (95% CI 1.44 to 2.36) (low-certainty evidence). Three trials reported RR of improved tear break-up time at 6 months and the estimates ranged from 0.90 (95% CI 0.77 to 1.04) to 4.00 (95% CI 2.25 to 7.12) (low-certainty evidence). Three trials reported frequency of artificial tear usage at 6 months without providing any estimates of effect; the direction of effect seem to be in favor of CsA (low-certainty evidence). Because of incomplete reporting of the results data or considerable statistical heterogeneity, we were only able to perform a meta-analysis on mean conjunctival goblet cell density. Mean conjunctival goblet cell density in the CsA treated group may be greater than that in the control group at the end of follow-up at four and 12 months (MD 22.5 cells per unit, 95% CI 16.3 to 28.8; low-certainty evidence). All but two trials reported adverse events that included burning and stinging. Participants treated with CsA may be more likely to have treatment-related adverse events than those who treated with vehicle (RR 1.33, 95% CI 1.00 to 1.78; low-certainty evidence).Other comparisons evaluated were CsA 0.05% plus artificial tears versus higher concentrations of CsA plus artificial tears (4 trials); CsA 0.05% versus placebo or vehicle (4 trials); CsA 0.1% plus artificial tears versus placebo or vehicle plus artificial tears (2 trials);CsA 0.1% cationic emulsion plus artificial tears versus vehicle plus artificial tears (2 trials); CsA 1% plus artificial tears versus placebo plus artificial tears (3 trials); and CsA 2% plus artificial tears versus placebo plus artificial tears (3 trials). Almost all of these trials reported P value or direction of effect only (mostly in favor of CsA), precluding calculation of between-group effect estimates or meta-analyses.

Despite the widespread use of topical CsA to treat dry eye, we found that evidence on the effect of CsA on ocular discomfort and ocular surface and tear film parameters such as corneal fluorescein staining, Schirmer's test, and TBUT is inconsistent and sometimes may not be different from vehicle or artificial tears for the time periods reported in the trials. There may be an increase in non-serious, treatment-related adverse effects (particularly burning) in the CsA group. Topical CsA may increase the number of conjunctival goblet cells. However, current evidence does not support that improvements in conjunctival mucus production (through increased conjunctival goblet cells) translate to improved symptoms or ocular surface and tear film parameters. All published trials were short term and did not assess whether CsA has longer-term disease-modifying effects. Well-planned, long-term, large clinical trials are needed to better assess CsA on long-term dry eye-modifying effects. A core outcome set, which ideally includes both biomarkers and patient-reported outcomes in the field of dry eye, is needed.