Topical interferon - A novel treatment for pseudophakic macular edema

Prevention and management of postcataract cystoid macular edema

PURPOSE OF REVIEW

This review highlights treatment options, both under investigation and currently available, for treating postcataract macular edema. An update on current clinical studies for postcataract macular edema has been summarized.

RECENT FINDINGS

Pseudophakic cystoid macular edema (PCME) is a common complication of cataract surgery leading to decreased visual acuity due to inflammation promoting vascular permeability and macular edema. There is no gold standard protocol for treatment with physicians choosing topical NSAIDs and corticosteroids most commonly. Recent developments in a therapeutic approach to PCME include improved delivery methods via implantation and improved drugs and combinational therapies.

SUMMARY

While PCME treatments are poorly studied due to their common sudden resolution without medical intervention, chronic PCME is debilitating for patients. Clinical studies show hope for improved drug delivery methods, practices to prevent potential PCME, and improved therapeutics.

Topical and Subcutaneous Interferon-Alpha for the Treatment of Refractory Inflammatory Macular Edema

PURPOSE

To evaluate the efficacy of topical interferon alpha-2b (tIFN a2b) and subcutaneous pegylated interferon alpha-2a (peg-IFN a2a) in the treatment of refractory pseudophakic (PME) and uveitic (UME) macular edema.

METHODS

Retrospective case series of patients with PME or UME that was non-responsive to conventional therapies. Topical IFN a2b drops (1 MIU/ml) were commenced four times a day. Non-responders were offered treatment with subcutaneous peg-IFN a2a starting at 180 mcg weekly.

RESULTS

Seven eyes of seven patients (three UME and four PME) were treated with tIFN a2b. Three eyes had complete ME resolution with tIFN treatment after a mean of 2.66 weeks (range 1-4 weeks) and no recurrence after a mean total course of 11.33 weeks (range 5-20 weeks). Two cases (both PME) had partial responses to tIFN treatment and two cases (both UME) failed to respond. Of the four eyes that incompletely responded to tIFN (treatment range 6 weeks to 4 months), three were treated with peg-IFN a2a, which invariably led to complete and sustained ME resolution. Adverse effects from topical treatment were mild and consisted mainly of superficial irritation. Adverse effects of subcutaneous treatment included nausea, vomiting, anorexia, and leukopenia, though none limited treatment.

CONCLUSIONS

Topical IFNa-2b appears safe and effective in isolation or in conjunction with topical steroids for the treatment of inflammatory macular edema (IME) in about half of patients in our small series. All partial and non-responders had complete disease resolution with systemic IFN. Topical IFN a2b should be considered in patients with refractory IME.

Interferons in vitreoretinal diseases; a review on their clinical application, and mechanism of action

PURPOSE

This review investigates the therapeutic benefits of interferons (IFNs) in vitreoretinal diseases, focusing on their regulatory roles in innate immunological reactions and angiogenesis. The study aims to categorize the clinical outcomes of IFN applications and proposes a molecular mechanism underlying their action.

METHODS

A systematic review was conducted using MEDLINE/PubMed, Web of Science, EMBASE, and Google Scholar databases to identify randomized clinical trials, case series, and case-control studies related to IFNs' impact on vitreoretinal diseases (1990-2022). The data synthesis involved an in-depth analysis of the anti-inflammatory and anti-angiogenesis effects of IFNs across various studies.

RESULTS

Our findings indicate that IFNs exhibit efficacy in treating inflammation-associated vitreoretinal disorders. However, a lack of sufficient evidence exists regarding the suitability of IFNs in angiogenesis-associated vitreoretinal diseases like choroidal neovascularization and diabetic retinopathies. The synthesis of data suggests that IFNs may not be optimal for managing advanced stages of angiogenesis-associated disorders.

CONCLUSION

While IFNs emerge as promising therapeutic candidates for inflammation-related vitreoretinal diseases, caution is warranted in their application for angiogenesis-associated disorders, especially in advanced stages. Further research is needed to elucidate the nuanced molecular pathways of IFN action, guiding their targeted use in specific vitreoretinal conditions.

Topical interferon therapy in uveitic macular edema

Purpose

To evaluate efficacy of topical interferon alfa-2b (IFN) in the treatment of uveitic macular edema (UME).

Methods

This is a prospective, interventional case study of patients with UME. Injection IFN was reconstituted into eye drops and a four times/day (QID) application was prescribed. Central macular thickness (CMT) on optical coherence tomography (OCT) scan was evaluated. Improvement in CMT by ≥50 μm from the baseline was studied in eyes with presenting CMT ≥400 μm.

Results

Twenty eyes of 20 patients with UME were studied: anterior uveitis (n = 3), anterior + intermediate uveitis (n = 5), posterior uveitis (n = 3), retinal vasculitis (n = 3), and panuveitis (n = 6). Mean CMT at the presentation was 423.3 μm (range: 270-604 μm), which improved at 1 month (n = 16), 2 months (n = 10), and ≥3 months (n = 11) follow-up, to 415.3 μm (range: 247-579 μm) (P = 0.411), 364.4 μm (range: 258-566 μm) (P = 0.099), 344 μm (range: 258-484 μm) (P = 0.001), respectively. Twelve eyes of 12 patients had presenting CMT ≥400 μm. In these cases, decrease in CMT by ≥50 μm was seen in 4/10, 4/5, and 5/6 eyes at 1 and 2 months and ≥3 months follow-up. Mean follow-up was 4 months (range: 1-17 months). Complete resolution of UME was seen only in three eyes. No ocular or systemic side effects were observed.

Conclusion

Topical IFN therapy in QID doses is safe but may have limited role in UME. Long-term therapy may improve its efficacy. Larger studies with dose modification, combination with other drugs, and with homogeneous uveitis population are recommended.

Evaluation of the additive effect of interferon α 2b with monthly intravitreal injection of bevacizumab in refractory diabetic macular edema

Background

To evaluate the additive effect of topical or sub-tenon injection of interferon (IFN)-α 2b in the treatment of refractory diabetic macular edema.

Methods

In this prospective study patients with center-involved DME who were unresponsive to 3 monthly consecutive IVB injections were recruited. Patients were divided into three groups: group1, received IFN- α 2b topical drop at a dose of 1mIU/ml four times a day for 3 months. Group 2, received a single sub-tenon injection of 1mIU/ml IFN- α 2b at the enrollment. Group 3 received artificial tears four times a day for 3 months (control group). All groups received three consecutive monthly IVB injections and were evaluated monthly up to 1 month following the last IVB injection.

Results

In this study, 59 eyes of 35 patients with refractory DME were assessed. The final follow-up showed that although CMT decreased in all groups, only patients in Group 2 had statistically significant lower CMT compared to their baseline values (change in CMT: − 117 ± 213 µm; p-value = 0.025). Comparison of CMT changes between three groups showed no statistically significant difference, although it was higher in group 2 (change in CMT: − 117 ± 213 µm (Group2) vs. − 49 ± 173 (Group 1) vs. − 36 ± 86 (Group 3); p-value = 0.085). Considering eyes with baseline CMT > 400 µm, sub-tenon injection of IFN α2b led to a significant reduction of CMT at the first month and final follow-up visit (CMT change: − 166 ± 210, − 145 ± 231 µm; p-value = 0.018 and 0.035, respectively). In this subgroup, eyes in Group 2 had lower CMT at the first month following treatment in comparison with the control group (CMT: 444 ± 123 µm vs. 544 ± 96 µm, p-value = 0.042). Alterations of CDVA were not statistically significant among groups, although patients in Group 1 had a significant improvement in vision at second and last follow up (CDVA change: − 0.23 ± 0.39, − 0.20 ± 0.43 logMAR; p-value = 0.030 and 0.010, respectively).

Conclusions

In short term, Sub-tenon injection of IFN might have an additive anatomical effect in eyes with refractory DME. Validation of this observation requires further prospective controlled studies.

Intensive topical interferon therapy in uveitic macular edema

Purpose

To evaluate the efficacy of intensive topical interferon alfa-2b (IFN) therapy in uveitic macular edema (UME).

Methods

This is a prospective, interventional case study of eyes with UME. Commercially available injection IFN for subcutaneous use was reconstituted to form eye drops and a dose of 6 times/day for 2 weeks, 5 times/day for next 2 weeks, followed by 4, 3, 2, 1 taper per month was prescribed. Optical coherence tomography (OCT) and clinical examination was done at 0, 2, 4, 8 weeks, and further as required.

Results

Nine eyes of 9 patients with UME were studied. Mean central macular thickness (CMT) at presentation was 522.2 μm (range: 408-803 μm). At 2-week, 1-month, and 2-month follow-up, mean CMT decreased to 451.6 μm (range: 322-524 μm), 375.8 μm (range: 287-480 μm), and 360.3 μm (range: 260-485 μm), respectively. Four eyes which showed inadequate response to previous topical IFN therapy (4 times/day) showed significant improvement with intensive therapy at 1 month follow-up. In 4 eyes, UME resolved completely with mean CMT 285.5 μm (range: 260-312 μm) at 7.5 weeks (range: 4-12 weeks). Study exit was seen in 2 cases due to inadequate response and relapse of uveitis. Mean follow up was 3.38 months (range: 1-5 months).

Conclusion

Intensive topical IFN therapy can be an alternative therapeutic option in the treatment of UME. Study of intraocular penetration, combination with other drugs, and the efficacy of IFN separately for different uveitic entities may explore new avenues in treatment of UME.

Improvement of pseudophakic cystoid macular edema with subconjunctival injections of interferon α2b:a case report

Purpose

To report a patient with resistant cystoid macular edema after an uneventful phacoemulsification cataract surgery who responded to subconjunctival interferon α2b injections.

Observations

This report describes a 60-year-old male patient with pseudophakic cystoid macular edema that was unresponsive to multiple courses of topical non-steroidal anti-inflammatory drugs and steroids during the follow-up period. Weekly subconjunctival interferon α2b (5 MIU/ml) was administered four times. Cystoid macular edema completely resolved after the 4th injection.During a six-month follow-up period, cystoid macular edema did not recur. No adverse local and systemic side effects were observed.

Conclusions and importance

Weekly subconjunctival interferon α2b injections might be a safe and effective treatment modality in the treatment of stubborn pseudophakic cystoid macular edema to conventional treatment.