Determining the effect of low-dose isotretinoin on proliferative vitreoretinopathy: the DELIVER trial

Clinical therapeutics for proliferative vitreoretinopathy in retinal detachment

Proliferative vitreoretinopathy (PVR) is an abnormal and prolonged healing response to retinal injury (retinal detachment, post retinal detachment surgery) characterised by: pre/subretinal membrane formation; retinal gliosis and retinal shortening, retinal pigment epithelium cell proliferation; and increased glial (mainly Mu¨ller cells), fibroblast and inflammatory cell (macrophage, lymphocyte) activity, leading to tractional retinal holes/breaks and multiple costly eye operations suffered by patients. PVR can cause retinal re-detachment following primary surgical intervention for rhegmatogenous retinal detachment. Vitrectomy and scleral buckling surgery are the main approaches for treating PVR complications of retinal detachment. Patients require many operations to remove the scar tissue but vision results are suboptimal, and do not meet patient expectations. Over the past 40 years, this has been one of the greatest challenges for vitreoretinal surgeons and patients. Despite previous large clinical trials of multiple candidate drug therapeutics, no proven adjunctive treatment currently exists to either prevent, reduce, or treat PVR formation in retinal detachment. Both cellular proliferation and the intraocular inflammatory response are realistic targets for adjunctive treatments in PVR. The cellular components of PVR periretinal membranes (retinal pigment epithelial, glial, inflammatory and fibroblastic cells) proliferate and are thus targets for antiproliferative agents. In recent years, several new therapeutics have been tested, and we present an updated review of the clinical therapeutics for PVR in retinal detachment.

Proliferative Vitreoretinopathy: Pathophysiology and Therapeutic Approaches

Proliferative vitreoretinopathy (PVR) is a complication of retinal detachment (RD) that is characterized by the development of retinal stiffness and contractile membranes on the surface or underside of the retina. It can occur in primary RD and make repair more challenging, or it can occur following initial successful RD repair and lead to re-detachment. Though our understanding of the pathophysiology underlying PVR membrane formation has grown based on cellular and animal models, there remains no currently approved medical therapy for treatment or prevention of PVR. Though some pharmacologic agents remain under active investigation, many have failed to show consistent benefit in human trials despite promising results from preclinical models. Further research is essential not only to enhance our understanding of PVR pathophysiology but also to identify novel therapeutic strategies for treating PVR in human patients.

Proliferative vitreoretinopathy: an update on the current and emerging treatment options

Proliferative vitreoretinopathy (PVR) remains the main cause of failure in retinal detachment (RD) surgery and a demanding challenge for vitreoretinal surgeons. Despite the large improvements in surgical techniques and a better understanding of PVR pathogenesis in the last years, satisfactory anatomical and visual outcomes have not been provided yet. For this reason, several different adjunctive pharmacological agents have been investigated in combination with surgery. In this review, we analyze the current and emerging adjunctive treatment options for the management of PVR and we discuss their possible clinical application and beneficial role in this subgroup of patients.

Intravitreal Injection of Bevacizumab for the Prevention of Postoperative Proliferative Vitreoretinopathy in High-Risk Patients Selected by Laser Flare Photometry

INTRODUCTION

To evaluate the effect of an intravitreal injection of bevacizumab at the time of rhegmatogenous retinal detachment (RRD) surgery, on postoperative proliferative vitreoretinopathy (PVR) in high-risk patients selected by laser flare photometry.

METHODS

This single-center observational retrospective cohort study included 137 consecutive patients who underwent pars plana vitrectomy and gas tamponade for primary RRD with increased aqueous flare between July 2016 and June 2021. From June 2019, an intravitreal injection of bevacizumab was administered as an adjunct to RRD repair. Patients who underwent surgery before this time and who did not receive intravitreal bevacizumab served as controls. The main outcome was the rate of retinal redetachment due to PVR.

RESULTS

The median flare value was 22.0 (16.5-36.5) pc/ms in the control group and 28.2 (19.7-41.0) pc/ms in the bevacizumab group (p = 0.063). Eyes treated with bevacizumab were more likely to have macula-off RRD (p = 0.003), grade B PVR (p = 0.038), and worse visual acuity (p = 0.004) than controls. The rate of PVR redetachment was significantly lower in the bevacizumab group (11.1%) than in the control (30.1%) (p = 0.012). This difference was more pronounced after adjusting for potential confounding factors (p = 0.005); the risk of developing PVR was 4.5-fold higher in controls (95% CI, 1.6-12.8). After adjustment, the final median visual acuity was also significantly higher in eyes treated with bevacizumab (p = 0.025).

CONCLUSION

This pilot study provides preliminary evidence that bevacizumab may reduce the risk of PVR-related recurrent RRD and improve visual outcomes in high-risk patients selected by laser flare photometry.

Translational and clinical advancements in management of proliferative vitreoretinopathy

PURPOSE OF REVIEW

Despite advancement in the surgical instrumentation and techniques, proliferative vitreoretinopathy (PVR) remains the most common cause for failure of rhegmatogenous retinal detachment (RRD) repair. This review discusses ongoing translational and clinical advancements in PVR.

RECENT FINDINGS

PVR represents an exaggerated and protracted scarring process that can occur after RRD. The primary cell types involved are retinal pigment epithelium, glial, and inflammatory cells. They interact with growth factors and cytokines derived from the breakdown of the blood-retinal barrier that trigger a cascade of cellular processes, such as epithelial-mesenchymal transition, cell migration, chemotaxis, proliferation, elaboration of basement membrane and collagen and cellular contraction, leading to overt retinal pathology. Although there are currently no medical therapies proven to be effective against PVR in humans, increased understanding of the risks factors and pathophysiology have helped guide investigations for molecular targets of PVR. The leading therapeutic candidates are drugs that mitigate growth factors, inflammation, and proliferation are the leading therapeutic candidates.

SUMMARY

Although multiple molecular targets have been investigated to prevent and treat PVR, none have yet demonstrated substantial evidence of clinical benefit in humans though some show promise. Advancements in our understanding of the pathophysiology of PVR may help develop a multipronged approach for this condition.

Combined 5-Fluorouracil and Low Molecular Weight Heparin for the Prevention of Postoperative Proliferative Vitreoretinopathy in Patients With Retinal Detachment: A Meta-Analysis

Background: Postoperative proliferative vitreoretinopathy (PVR) remains a dilemma for retinal surgeons. We performed a literature search and meta-analyses to figure out whether combined 5-fluorouracil (5-FU) and low molecular weight heparin (LMWH) treatment were effective in improving the primary success of vitrectomy and preventing postoperative PVR occurrence in patients with retinal detachment (RD).

Methods: Databases including PubMed, Embase, the Cochrane library, and China National Knowledge Infrastructure (CNKI) were searched from inception to May 2021. Comparative studies approaching the effects of combined 5-FU and LMWH on postoperative PVR were included. Quality assessment was performed using RoB 2 and ROBINS-I tool. Study data were pooled using Review manager 5.4.1. The main outcomes were: the primary success of vitrectomy at 6 months and the postoperative PVR occurrence. The additional outcomes were: number of patients who underwent vitreoretinal reoperations and the number of vitreoretinal reoperations due to postoperative PVR. Subgroup analyses and sensitivity analyses were also performed.

Results: Six clinical trials with a total of 1,208 participants were included. We found that combined 5-FU and LMWH infusion did not improve the primary success of vitrectomy at 6 months (RR = 1.00, 95% CI = 0.95, 1.07, P = 0.89, I² = 50%). Also, the conjunct therapy had no effect on reducing the number of patients who underwent vitreoretinal reoperations (RR = 1.00, 95% CI = 0.78, 1.28, P = 1.00, I² = 42%). The overall effect of the treatment on preventing postoperative PVR was negative. However, in patients with PVR grade C (PVRC) before intervention, the 5-FU and LMWH treatment significantly reduced PVR occurrence. Visual acuity was not different between the treatment and control groups. Nevertheless, in one RCT, a significant reduction of VA was observed in the treatment group in macular-sparing patients with RD. No complications were attributed to the conjunct therapy.

Conclusions: The combined 5-FU and LMWH treatment neither improved the primary success of vitrectomy at 6 months nor decreased number of patients who underwent vitreoretinal reoperations. Thus, the treatment should not be routinely used in vitrectomy for patients with RD. However, the treatment proved beneficial in reducing postoperative PVR in patients with PVRC before intervention. More high-quality clinical trials are needed to confirm the results.

Systematic Review Registration:https://inplasy.com/inplasy-2021-8-0117/, identifier: INPLASY202180117.

Pharmacotherapy as an adjunct to vitrectomy

Vitreoretinal surgery has advanced extensively from the first days of vitrectomy. During the last decade, new developments in intravitreal pharmacotherapy have created new opportunities to enhance the surgical outcomes of our patients. In this article, we review and discuss some of the supporting evidence of different pharmacotherapies that may be used as an adjunct to vitrectomy for select common etiologies. Triamcinolone acetonide, dexamethasone, and angiogenesis inhibitors are among the most commonly used drugs given their safety profile and proven efficacy. Other pharmaceuticals have also shown promising results in small studies. The adoption of individualized medical treatments prior, during, and after vitrectomy will continue to increase as new evidence supporting the benefit of pharmacotherapy as an adjunct to vitrectomy becomes available.

Molecular Targets for Proliferative Vitreoretinopathy

While innovations in the surgical management of retinal detachment (RD) with proliferative vitreoretinopathy (PVR) have significantly improved anatomic and visual outcomes over the years, recurrent RD due to PVR remains the major limitation to success. There are currently no medical therapies proven to be effective against PVR in humans. Increased understanding of the pathophysiology and risk factors for PVR have helped guide investigations for molecular targets. Drugs that counteract inflammation, proliferation, and growth factors are the leading candidates for treatment of PVR. This review discusses the ongoing search for pharmacologic therapies, with an emphasis on the results of recent clinical investigations.

[Proliferative vitreoretinopathy prophylaxis : Mission (im)possible]

BACKGROUND

Proliferative vitreoretinopathy (PVR) is one of the most important complications following vitreoretinal surgery. So far, surgical strategies have been the gold standard in treatment. Pharmacological approaches for prevention and treatment of PVR are under clinical investigation and intervene in different phases of the PVR cascade.

METHODS

The relevant literature as well as own data and experience with PVR are discussed in this review article. The most important aspects of pharmacological approaches for PVR prophylaxis and treatment are explained.

RESULTS

A prophylactic use of systemic prednisone administration as an anti-inflammatory substance showed contradictory results, while there was no additional benefit for intravitreal triamcinolone. Orally administered isotretinoin also seems to be able to minimize the formation of PVR after retinal reattachment surgery, whereas there was no improvement in the success rate in established PVR. Cell proliferation inhibitors have already been extensively studied. The combined intravitreal prophylactic approach of 5‑fluorouracil and low molecular weight heparin was recently further investigated in a multicenter, placebo-controlled study and showed a positive effect in some studies. New preclinical and experimental approaches include the inhibition of growth factors, modulation of integrin activity and the induction of apoptosis.

CONCLUSION

Most clinical studies dealt with an anti-inflammatory or antiproliferative approach. So far, no pharmacological substance has been established for the treatment of PVR but there are promising approaches for prophylaxis.

Salinomycin inhibits proliferative vitreoretinopathy formation in a mouse model

Proliferative vitreoretinopathy (PVR) is a progressive disease that develops in a subset of patients who undergo surgery for retinal detachment repair, and results in significant vision loss. PVR is characterized by the migration of retinal pigment epithelial (RPE) cells into the vitreous cavity, where they undergo epithelial-to-mesenchymal transition and form contractile membranes within the vitreous and along the retina, resulting in recurrent retinal detachments. Currently, surgical intervention is the only treatment for PVR and there are no pharmacological agents that effectively inhibit or prevent PVR formation. Here, we show that a single intravitreal injection of the polyether ionophore salinomycin (SNC) effectively inhibits the formation of PVR in a mouse model with no evidence of retinal toxicity. After 4 weeks, fundus photography and optical coherence tomography (OCT) demonstrated development of mean PVR grade of 3.5 (SD: 1.3) in mouse eyes injected with RPE cells/DMSO (vehicle), compared to mean PVR grade of 1.6 (SD: 1.3) in eyes injected with RPE cells/SNC (p = 0.001). Additionally, immunohistochemistry analysis showed RPE cells/SNC treatment reduced both fibrotic (αSMA, FN1, Vim) and inflammatory (GFAP, CD3, CD20) markers compared to control RPE cells/DMSO treatment. Finally, qPCR analysis confirmed that Tgfβ, Tnfα, Mcp1 (inflammatory/cytokine markers), and Fn1, Col1a1 and Acta2 (fibrotic markers) were significantly attenuated in the RPE cells/SNC group compared to RPE/DMSO control. These results suggest that SNC is a potential pharmacologic agent for the prevention of PVR in humans and warrants further investigation.

Oral isotretinoin and topical retinoid use in a series of young patients with ocular melanoma

Purpose

To describe the first series of six young uveal melanoma (UM) patients with oral isotretinoin and/or topical retinoid therapy prior to diagnosis.

Observations

The case series is based on clinical observations at our UM quaternary referral center. Six UM patient cases are reported, ages 16–44 years old. All had been using either oral (isotretinoin) and/or topical (tretinoin or tazarotene) retinoid treatment (3 months–~10 years) prior to or at the time of diagnosis (3 of 6 cases). All patients had ocular complaints on presentation, and the onset of certain symptoms corresponded with the course of retinoids. Other potential risk factors or relevant history included Caucasian background, cone-rod dystrophy and active smoker status (Case 2), family history of UM and pregnancy at time of diagnosis (Case 3), past smoking and possible secondary Chernobyl exposure as a baby (Case 5). All patients were treated with proton beam radiotherapy and currently have no sign of recurrent or metastatic disease.

Conclusions and importance

Retinoid therapy has been linked to various benign and/or reversible effects on the anterior and posterior eye, though pathophysiology remains not well understood. Uveal melanoma (UM) is a rare cancer diagnosis in young adults. We report here the first case series of young UM patients with a history of retinoid use and ocular complaints. No causal link is claimed and further systematic epidemiologic and biologic study of retinoid therapy and ocular impact may provide additional relevant data, particularly in young ocular melanoma patients.

Low dose of isotretinoin: A comprehensive review

Isotretinoin is a first-generation retinoid initially approved for the treatment of severe cases of acne vulgaris (nodulocystic acne). Because of its broad anti-inflammatory and immunomodulatory properties, it has been used beyond its initial approval in a myriad of other indications. Adverse effects of isotretinoin vary from xerosis to teratogenicity. Herein, we reviewed the literature, through date-unlimited PubMed search, from inception till December 2019, using the following search terms: "low-dose isotretinoin" and "dermatology," "isotretinoin and safety," "isotretinoin, off-label uses," "isotretinoin and male fertility," "isotretinoin, iPLEDGE system," aiming to deliver a therapeutic update relevant to clinical practice. All English-language articles were considered with no limitation based on the articles' type. Low-dose isotretinoin is not limited to old and novel dermatological conditions, but also showed promising results in the field of infertility and safety in the field of gastroenterology. We also highlight on the safety profile of the drug and experts' recommendations to enhance safety measures to decrease fetal risk while on isotretinoin.

TRActional DIabetic reTInal detachment surgery with co-adjuvant intravitreal dexamethasONe implant: the TRADITION STUDY

AIM

Main failure of diabetic tractional retinal detachment (TRD) surgery is the development of proliferative vitreoretinopathy (PVR), causing higher re-detachment rates. We investigated whether the use of dexamethasone (DEX) implant at the end of pars plana vitrectomy (PPV) with silicone oil tamponade might have an impact on these outcomes.

DESIGN

Comparative, nonrandomized, retrospective study.

PARTICIPANTS

A total of 148 eyes from 148 patients that underwent PPV with silicone oil tamponade for diabetic TRD (with DEX implant, n = 52; without DEX implant, n = 96).

METHODS

Consecutive patients' records were reviewed for time between TRD diagnosis and surgery; lens status before surgery and after 6, 12, and 24 months; retina attachment rate after primary PPV; change in postoperative PVR severity; rate of re-detachment at 6, 12, and 24 months; use of IOP lowering treatment after 6, 12, and 24 months; surgery details; intra- and postoperative complications. Correlations between outcome measures, postoperative PVR severity, and re-detachment rates were analyzed.

MAIN OUTCOME MEASURES

Change in postoperative PVR severity and retinal re-detachment rates with and without the adjuvant use of DEX implant.

RESULTS

Retinal re-detachment rates were significantly higher in the group of patients that did not receive DEX implant [11/96 (11.5%) vs. 0/52 (0%), p = 0.049; 11/84 (12.9%) vs. 4/52 (7.7%), p = 0.007; 14/71 (19.7%) vs. 5/52 (10%) p < 0.001 at 6, 12, and 24 months, respectively]. PVR severity correlated with retinal status at 12 and 24 months (p = 0.018 and p = 0.027, respectively). The difference in PVR severity between the two groups was statistically significant at 6, 12, and 24 months (p < 0.001).

CONCLUSIONS

DEX implant at the end of PPV in patients with diabetic TRD improves PVR severity and decreases re-detachment rates. This should be considered as an option in the customized treatment of TRD.