Efficacy and safety of multiple intravitreal triamcinolone injections for refractory diabetic macular oedema

Safety and Efficacy of Intravitreal Preservative-Free Triamcinolone Acetonide (Triesence) for Macular Edema

PURPOSE

To evaluate the efficacy and safety of preservative-free triamcinolone acetonide (Triesence) for the treatment of macular edema.

METHODS

A retrospective study was conducted on patients who attended a tertiary retinal clinic from June 2009 to July 2012 with macular edema due to various causes. Patients who received at least 1 intravitreal Triesence injection and completed 6 months of follow-up were recruited. Data, including best-corrected Snellen visual acuity, central macular thickness (CMT), intraocular pressure (IOP), and adverse events (AEs), were collected at baseline, week 1, month 1, month 3, and month 6 after initiation of treatment. Snellen visual acuity was converted to visual acuity score (VAS) for statistical analysis using paired t-tests and linear regression.

RESULTS

One hundred two eyes from 102 patients were included in the study. Mean VAS was significantly improved at all follow-up time points compared to baseline (P≤0.002), with highest mean gain at month 1 (6.1±8.9 letters). Mean CMT decreased significantly at all follow-up points compared to baseline (P≤0.0005), with the greatest reduction at week 1 (146.6±109.4 μm). A total of 22 AEs were observed, and IOP elevation was the most common AE related to Triesence treatment (17/22, 77.3%). No sterile or infectious endophthalmitis was observed.

CONCLUSION

Intravitreal Triesence improves visual acuity and reduces macular thickness in eyes with macular edema from various causes. Treatment-associated IOP elevation was manageable with antiglaucoma medications. There were no serious vision-threatening complications associated with intravitreal Triesence therapy during the study period.

New treatments for diabetic macular edema

This work comprehensively reviews the latest treatment options for diabetic macular edema (DME) used in its management and presents further work on the topic. Diabetic retinopathy is an important and increasingly prevalent cause of preventable blindness worldwide. To meet this increasing burden there has recently been a proliferation of pharmacological therapies being used in clinical practice. A variety of medical treatment options now exist for DME. These include non-steroidal anti-inflammatory drugs such as nepafenac, as well as intravitreal steroids like triamcinolone (kenalog). Long-term results up to 7 years after commencing treatment are presented for triamcinolone. Studies are reviewed on the use of dexamethasone (ozurdex) and fluocinolone (Retisert and Iluvien implants) including the FAME studies. A variety of anti-vascular endothelial growth factor (anti-VEGF) agents used in DME are considered in detail including ranibizumab (lucentis) and the RESTORE, RIDE, RISE and Diabetic Retinopathy Clinical Research Network (DRCR.net) studies. Bevacizumab (avastin) and pegaptinib (macugen) are also considered. The use of aflibercept (eylea) is reviewed including the significance of the DA VINCI, VISTA-DME, VIVID-DME and the DRCR.net studies which have recently suggested potentially greater efficacy when treating DME for aflibercept in patients with more severely reduced visual acuity at baseline. Evidence for the anti-VEGF agent bevasiranib is also considered. Studies of anti-tumour necrosis factor agents like infliximab are reviewed. So are studies of other agents targeting inflammation including minocycline, rapamycin (sirolimus) and protein kinase C inhibitors such as midostaurin and ruboxistaurin. The protein kinase C β inhibitor Diabetic Macular Edema Study is considered. Other agents which have been suggested for DME are discussed including cyclo-oxygenase-2 inhibitors like celecoxib, phospholipase A2 inhibitors, recombinant erythropoietin, and monoclonal anti-interleukin antibodies such as canakinumab. The management of DME in a variety of clinical scenarios is also discussed - in newly diagnosed DME, refractory DME including after macular laser, and postoperatively after intraocular surgery. Results of long-term intravitreal triamcinolone for DME administered up to seven years after commencing treatment are considered in the context of the niche roles available for such agents in modern management of DME. This is alongside more widely used treatments available to the practitioner such as anti-VEGF agents like aflibercept (Eylea) and ranibizumab (Lucentis) which at present are the mainstay of pharmacological treatment of DME.

The effects of commonly used intravitreal steroids on proliferation index of ciliary body-derived mesenchymal stem cells: an in vitro study

AIM

To investigate the effects of commonly used intravitreal steroids on survival and proliferation (namely, proliferation index) of ciliary body-derived mesenchymal stem cells (CB-MSC).

METHODS

CB-MSCs were isolated from newborn rats' eye, and they were expanded in the medium. Commonly used intravitreal steroids such as dexamethasone (Dex) and triamcinolone acetonide (TA) were added into the medium at commonly used concentration in clinical practice (0.1 mg/mL) and at lower concentration (0.01 mg/mL). Proliferation indexes of CB-MSCs were analyzed with the xCELLigence system at nine consecutive times (at 3rd, 6th, 21th, 30th, 45th, 60th, 75th, 90th and 100th h).

RESULTS

Both TA and Dex at both 0.01 mg/mL and 0.1 mg/mL concentrations had negative effect on proliferation indexes of CB-MSC. Although negative effect of TA on proliferation index of CB-MSC at both concentrations was not statistically significant, statistically significant negative effect of Dex at 0.01 mg/mL concentration started 60th h (p = 0.017) and 0.1 mg/mL concentration started 30th h (p = 0.014).

DISCUSSION

Even therapeutic doses of intravitreal corticosteroid agents might have negative effects on limited numbers of stem cells. Especially, Dex caused statistically significant toxic effects on CB-MSCs even at lower concentrations of those used clinically. These novel findings deserve further in vivo investigations.

Effects of triamcinolone acetonide on human trabecular meshwork cells in vitro

Aim:

To study the effects of triamcinolone acetonide (TA) on cultured human trabecular meshwork (HTM) cells.

Materials and Methods:

HTM cells were cultured and treated with 125, 250, 500 and 1000 μg/mL concentration of TA for 24 h. The cells were treated with both crystalline TA (TA-C) (commercial preparation) and solubilized TA (TA-S). Cell viability was measured by a trypan blue dye exclusion test. The activity of caspse-3/7 was measured by a fluorescence caspase kit and DNA laddering was evaluated by electrophoresis on 3% agarose gel. Levels of lactate dehydrogenase (LDH) were assessed with LDH cytotoxicity assay kit-II.

Results:

Mean cell viabilities of HTM cells after 24 h exposure to TA-C 125, 250, 500, and 1000 μg/mL were 75.4 ±2.45% (P < 0.0001), 49.43 ± 1.85% (P < 0.0001), 17.07 ± 2.39% (P < 0.0001), and 3.7 ± 0.9% (P < 0.0001), respectively, compared with the untreated HTM cells 92.49 ± 1.21%. The mean cell viabilities with 125, 250, 500, and 1000 μg/mL of TA-S were 94.47 ± 1.60% (P > 0.05), 90.13 ± 0.40% (P < 0.01), 85.57 ± 0.47% (P < 0.001), and 71.67 ± 3.30% (P < 0.0001), respectively, compared to DMSO-equivalent cultures. Untreated HTM control had a cell viability of 96.57 ± 1.98%. DMSO-treated controls of 125, 250, 500, and 1000 μg/mL had a cell viability of 94.73 ± 0.57%, 96.97 ± 1.08%, 93.97 ± 1.85%, and 97.27 ± 1.15%, respectively. There was no increase of caspase-3/7 activity in cultures treated with either TA-C or TA-S. DNA laddering showed no bands in the TA-C or TA-S treated cultures. There were significantly higher LDH release rates at all concentrations of TA-C compared to TA-S.

Conclusions:

Results show that the effect of TA-C and TA-S on HTM cells is due to cell death by necrosis at all concentrations except 125 μg/mL of TA-S. Elevated levels of LDH confirmed necrotic cell death. Our study also infers the relative safety of TA-S over TA-C.

Intravitreal steroids for the treatment of retinal diseases

Diabetic macular edema (DME), pseudophakic cystoid macular edema (CME), age-related macular degeneration (AMD), retinal vascular occlusion (RVO), and uveitis are ocular conditions related to severe visual impairment worldwide. Corticosteroids have been widely used in the treatment of these retinal diseases, due to their well-known antiangiogenic, antiedematous, and anti-inflammatory properties. Intravitreal steroids have emerged as novel and essential tools in the ophthalmologist's armamentarium, allowing for maximization of drug efficacy and limited risk of systemic side effects. Recent advances in ocular drug delivery methods led to the development of intraocular implants, which help to provide prolonged treatment with controlled drug release. Moreover, they may add some potential advantages over traditional intraocular injections by delivering certain rates of drug directly to the site of action, amplifying the drug's half-life, contributing in the minimization of peak plasma levels of the drug, and avoiding the side effects associated with repeated intravitreal injections. The purpose of this review is to provide an update on the use of intravitreal steroids as a treatment option for a variety of retinal diseases and to review the current literature considering their properties, safety, and adverse events.

Baseline central macular thickness predicts the need for retreatment with intravitreal triamcinolone plus laser photocoagulation for diabetic macular edema

Purpose

To identify baseline characteristics that predict the number of treatments with intravitreal triamcinolone acetonide (IVTA) plus laser photocoagulation needed to treat diabetic macular edema over a 2-year period.

Methods

Individual data from 42 eyes of 42 participants treated with IVTA plus laser photocoagulation for diabetic macular edema during a prospective, randomized, double-masked, placebo-controlled trial were used for this post hoc analysis. Baseline characteristics – age, gender, best-corrected visual acuity, glycosylated hemoglobin, phakic status, intraocular pressure, and central macular thickness (CMT) – were correlated with the number of IVTA plus laser treatments received during the 2 years of this study.

Results

The median number of treatments received over the 2-year period was 2.5 (interquartile range 1.0–3.0), with 21 (50%) eyes needing three or more treatments. Eyes that received more IVTA plus laser treatments had a higher mean baseline CMT and eyes with a higher baseline CMT were more likely to receive three or more treatments (odds ratio 5.13, 95% confidence interval 1.75–15.04, P=0.003 per 100 μm increase in CMT). No significant relationship was found between other baseline characteristics and the number of IVTA plus laser treatments received.

Conclusion

Higher baseline CMT was strongly linked with receiving more IVTA plus laser treatments. These patients may be at higher risk of developing dose-dependent steroid-related adverse events, cataract progression, and intraocular pressure rise.

Current treatments in diabetic macular oedema: systematic review and meta-analysis

OBJECTIVES

The aim of this systematic review is to appraise the evidence for the use of anti-VEGF drugs and steroids in diabetic macular oedema (DMO) as assessed by change in best corrected visual acuity (BCVA), central macular thickness and adverse events

DATA SOURCE

MEDLINE, EMBASE, Web of Science with Conference Proceedings and the Cochrane Library (inception to July 2012). Certain conference abstracts and drug regulatory web sites were also searched.

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS AND INTERVENTIONS

Randomised controlled trials were used to assess clinical effectiveness and observational trials were used for safety. Trials which assessed triamcinolone, dexamethasone, fluocinolone, bevacizumab, ranibizumab, pegaptanib or aflibercept in patients with DMO were included.

STUDY APPRAISAL AND SYNTHESIS METHODS

Risk of bias was assessed using the Cochrane risk of bias tool. Study results are narratively described and, where appropriate, data were pooled using random effects meta-analysis.

RESULTS

Anti-VEGF drugs are effective compared to both laser and placebo and seem to be more effective than steroids in improving BCVA. They have been shown to be safe in the short term but require frequent injections. Studies assessing steroids (triamcinolone, dexamethasone and fluocinolone) have reported mixed results when compared with laser or placebo. Steroids have been associated with increased incidence of cataracts and intraocular pressure rise but require fewer injections, especially when steroid implants are used.

LIMITATIONS

The quality of included studies varied considerably. Five of 14 meta-analyses had moderate or high statistical heterogeneity.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

The anti-VEGFs ranibizumab and bevacizumab have consistently shown good clinical effectiveness without major unwanted side effects. Steroid results have been mixed and are usually associated with cataract formation and  intraocular pressure increase. Despite the current wider spectrum of treatments for DMO, only a small proportion of patients recover good vision (≥20/40), and thus the search for new therapies needs to continue.

Clinical development of new treatments for diabetic macular oedema

The benchmark treatment for diabetic macular oedema, the major cause of visual impairment in patients with diabetes mellitus, has traditionally been laser photocoagulation; however, as laser treatment does not always improve vision or even prevent further loss in many cases, several new pharmacotherapies that are injected into the vitreous for diabetic macular oedema have been successfully trialled over the past decade. Others are currently being evaluated. The two major classes of these drugs are steroids and vascular endothelial growth factor antagonists. In this article we briefly review the major clinical studies recently conducted in this field.

Review and update of intraocular therapy in noninfectious uveitis

PURPOSE OF REVIEW

To review new clinically relevant data regarding the intraocular treatment of noninfectious uveitis.

RECENT FINDINGS

Triamcinolone acetonide, the most commonly used intravitreal corticosteroid for treatment of uveitis and uveitic macular oedema has a limited duration of action and is associated with a high risk of corticosteroid-induced intraocular pressure (IOP) rise and cataract. Recent advances have led to the development of sustained-release corticosteroid devices using different corticosteroids such as dexamethasone and fluocinolone acetonide. Treatment options for patients who have previously exhibited corticosteroid hypertensive response have also expanded through the use of new noncorticosteroid intravitreal therapeutics such as methotrexate and antivascular endothelial growth factor (anti-VEGF) agents.

SUMMARY

Ozurdex dexamethasone implant appears to have a better safety profile, and a slightly long-lasting effect than triamcinolone acetonide. The Retisert implant allows the release of corticosteroids at a constant rate for 2.5 years, but it requires surgical placement and its use is associated with a very high risk of cataract and requirement for IOP-lowering surgery. For patients who are steroid responders, methotrexate may offer a better alternative to corticosteroid treatment than anti-VEGF agents, but controlled trials are required to confirm this.

Drug safety evaluation of intravitreal triamcinolone acetonide

INTRODUCTION

Triamcinolone acetonide (TA) is a steroidal drug that has been widely administered intravitreally for retinal and choroidal conditions. Safety of steroidal products for intraocular use is essential because of their risk of ocular adverse events. This review comprehensively discusses the safety of intravitreal administration of TA.

AREAS COVERED

This paper analyzes the mechanisms of action and key pharmacokinetic attributes and provides a discussion of the main clinical trials investigating clinical applications of intravitreal TA. The safety of intravitreal TA is evaluated through a search of the Medline database from 1980 to 2011. The most relevant literature on the safety of intravitreal TA is also discussed.

EXPERT OPINION

The complications of intravitreal TA therapy include secondary ocular hypertension in about 20 - 40% of eyes, steroid-induced cataract in about 15 - 20% of cases and postinjection infectious endophthalmitis and pseudoendophthalmitis in less than 1%. TA is an effective drug for various retinal and choroidal diseases when delivered intravitreally. It may imply an off-label use and it may be associated with ocular adverse events. Intravitreal TA is not associated with significant systemic safety risks.

Efficacy of intravitreal triamcinolone acetonide in long standing diabetic macular edema: a microperimetry and optical coherence tomography study

PURPOSE

To investigate the efficacy of intravitreal triamcinolone acetonide in patients suffering from diffuse long standing diabetic macular edema, by the assessment of retinal thickness and retinal function by means of optical coherence tomography (OCT) and microperimetry-1.

METHODS

Twenty eyes received 8 mg in 0.2 mL preservative free intravitreal triamcinolone injection delivered through the pars plana. The best corrected visual acuity (BCVA), foveal thickness, and the average retinal sensitivity of the 45 stimuli were considered in our study. Patients were instructed to attend for OCT and microperimetry-1 follow-up at baseline, 1, 3, and 6.

RESULTS

At the baseline, mean macular thickness was 692 micro +/- 70 micro; mean visual acuity was 0.13 +/- 0.09. Mean macular sensitivity determined with the microperimetry-1 was 6.85 dB +/- 2.1 dB. At the 1 month follow-up, mean OCT macular thickness decreased to 348.28 micro +/- 132.10 micro (P = 0.0001); mean BCVA improved to 0.23 +/- 0.15 (P = 0.019); mean retinal sensitivity improved to 8.71 dB +/- 2.79 dB (P = 0.03). At the 3 months follow-up, mean OCT macular thickness changed to 363.7 micro +/- 123.52 micro (P = 0.0002); mean BCVA was 0.23 +/- 0.15 (P = 0.0024); mean retinal sensitivity 8.54 dB +/- 2.78 dB (P = 0.048). Six months after the injection, mean OCT macular thickness was 460.61 micro +/- 104.9 micro (P > 0.05); mean BCVA was 0.15 (P > 0.05); mean retinal sensitivity 7.54 dB +/- 2.58 dB (P > 0.05).

CONCLUSION

In our study, we found intravitreal effective in improving BCVA, macular thickness, and retinal sensitivities during the first 3 months. At 6 months, follow-up of the data were not dissimilar to those obtained at baseline. Further investigation is warranted to asses the correlation among daily life visual performance, retinal sensitivities, and macular thickness.

Therapies for hyperglycaemia-induced diabetic complications: from animal models to clinical trials

Diabetic complications — the long-term damage to various organ systems — are a great cause of mortality and morbidity in both type 1 and type 2 diabetes. There are currently few therapeutic options to prevent or ameliorate these complications.

High blood glucose levels and the subsequent metabolic consequences of hyperglycaemia are widely considered the primary event that initiates diabetic complications, although there is accumulating evidence that impaired insulin signalling arising from insulin deficiency and insulin resistance may also have a pathogenic role.

Vascular dysfunction is a prominent complication of diabetes that is widely held to underlie damage to organ systems such as the macrovasculature, kidneys, eyes and nerves. Other consequences of diabetes, such as dyslipidaemia and hypertension, are key modifiers of vascular injury and act as accelerators of diabetic complications.

Numerous pathogenic mechanisms, including increased polyol pathway flux and mitochondrial activity, activation of protein kinase C and NADPH oxidase and signalling through the receptor for advanced glycation end products (RAGE) pathway, seem to form a central pathogenic axis that is common to most, if not all, of the complications of diabetes. These disorders all promote excess production of pro-oxidative molecules. Organ-specific mechanisms, such as diminished growth factor support and repair pathway activation, must also be considered.

Few animal models of diabetic complications faithfully reflect the advanced stages of organ pathology seen in humans. Current models can be viewed as potentially illustrating early biochemical and functional disorders of diabetes that ultimately lead to advanced pathology. New animal models are being developed using both a reductionist approach for examining specific gene products of interest and also by combining diverse molecular and physiological risk factors.

Control of blood glucose levels and lipids remains the most meaningful approach for preventing diabetic complications. This strategy is likely to be complemented by a diverse range of more focused therapeutics that have emerged from mechanistic studies in animal models and which are currently in clinical development. Some of these, such as those targeting cardiovascular disease, have the potential to affect several diabetic complications, whereas others focus on intervening in organ-specific pathogenic mechanisms. It is probable that combination therapies aimed at the hyperglycaemia-driven pathogenic axis and also at organ-specific disorders will provide the most effective approach to treating the diverse complications of diabetes.

Long-term diabetes increases the likelihood of developing complications such as macrovascular disease, nephropathy, retinopathy and neuropathy. This Review highlights the range of pathologies that are precipitated by hyperglycaemia and discusses recent developments in preclinical and clinical research for each of these complications.

Long-term diabetes increases the likelihood of developing secondary damage to numerous systems, and these complications represent a substantial cause of morbidity and mortality. Establishing the causes of diabetes remains the key step towards eradicating the disease, but the prevention and amelioration of diabetic complications is equally important for the millions of individuals who already have the disease or are likely to develop it before prophylaxis or a cure become routinely available. In this Review, we focus on four common complications of diabetes, discuss the range of pathologies that are precipitated by hyperglycaemia and highlight emerging targets for therapeutic intervention.