DIDANOSINE RETINAL TOXICITY

PREVALENCE OF DIDANOSINE-RELATED RETINAL TOXICITY AT AN URBAN ACADEMIC CENTER AS DIAGNOSED WITH ULTRA-WIDEFIELD IMAGING

PURPOSE

Antiretroviral therapy has revolutionized HIV treatment with didanosine (DDI) as a pioneering drug. However, DDI has been associated with retinal toxicity, characterized by peripheral chorioretinal degeneration with macular sparing. Despite its clinical recognition, the prevalence and risk factors for didanosine-induced retinopathy are not well described.

METHODS

This retrospective case series analyzed 127 DDI-treated patients at Weill Cornell Medicine Department of Ophthalmology. Inclusion criteria included at least 6 months of DDI use and available ultra-widefield imaging. Patients were categorized as affected or unaffected based on retinal imaging assessed by two reviewers. The affected group was further divided into "probable" or "possible" retinopathy. Patient demographics, DDI usage characteristics, and imaging findings were analyzed with statistical comparisons drawn between affected and unaffected cohorts.

RESULTS

Of the 127 patients, 9 (7%) showed signs of didanosine-induced retinal toxicity. On average, the affected group was older compared with the unaffected group (65.1 vs. 56.5 years, P = 0.025), with lower BMI (23.2 vs. 27.4, P = 0.04), and older at the start of the treatment (51.6 vs. 40.8 years, P = 0.026). Mild phenotypes with peripheral pigmentary changes were also identified using ultra-widefield imaging.

CONCLUSION

This pioneering academic study highlighted a notable prevalence of DDI-induced retinal toxicity. Statistical analysis demonstrated age, BMI, and age at treatment initiation as potential risk factors. Ultra-widefield autofluorescence emerged as a valuable tool in detecting and delineating findings. Follow-up studies are needed to determine the necessity of regular screening for individuals on or with a history of didanosine use.

Mitochondrial retinopathies and optic neuropathies: The impact of retinal imaging on modern understanding of pathogenesis, diagnosis, and management

Advancements in ocular imaging have significantly broadened our comprehension of mitochondrial retinopathies and optic neuropathies by examining the structural and pathological aspects of the retina and optic nerve in these conditions. This article aims to review the prominent imaging characteristics associated with mitochondrial retinopathies and optic neuropathies, aiming to deepen our insight into their pathogenesis and clinical features. Preceding this exploration, the article provides a detailed overview of the crucial genetic and clinical features, which is essential for the proper interpretation of in vivo imaging. More importantly, we will provide a critical analysis on how these imaging modalities could serve as biomarkers for characterization and monitoring, as well as in guiding treatment decisions. However, these imaging methods have limitations, which will be discussed along with potential strategies to mitigate them. Lastly, the article will emphasize the potential advantages and future integration of imaging techniques in evaluating patients with mitochondrial eye disorders, considering the prospects of emerging gene therapies.

Current insights and molecular docking studies of HIV-1 reverse transcriptase inhibitors

Human immunodeficiency virus (HIV) causes acquired immunodeficiency syndrome (AIDS), a lethal disease that is prevalent worldwide. According to the Joint United Nations Programme on HIV/AIDS (UNAIDS) data, 38.4 million people worldwide were living with HIV in 2021. Viral reverse transcriptase (RT) is an excellent target for drug intervention. Nucleoside reverse transcriptase inhibitors (NRTIs) were the first class of approved antiretroviral drugs. Later, a new type of non-nucleoside reverse transcriptase inhibitors (NNRTIs) were approved as anti-HIV drugs. Zidovudine, didanosine, and stavudine are FDA-approved NRTIs, while nevirapine, efavirenz, and delavirdine are FDA-approved NNRTIs. Several agents are in clinical trials, including apricitabine, racivir, elvucitabine, doravirine, dapivirine, and elsulfavirine. This review addresses HIV-1 structure, replication cycle, reverse transcription, and HIV drug targets. This study focuses on NRTIs and NNRTIs, their binding sites, mechanisms of action, FDA-approved drugs and drugs in clinical trials, their resistance and adverse effects, their molecular docking studies, and highly active antiretroviral therapy (HAART).

Polymer-Based Nanoparticles as Drug Delivery Systems for Purines of Established Importance in Medicine

Many purine derivatives are active pharmaceutical ingredients of significant importance in the therapy of autoimmune diseases, cancers, and viral infections. In many cases, their medical use is limited due to unfavorable physicochemical and pharmacokinetic properties. These problems can be overcome by the preparation of the prodrugs of purines or by combining these compounds with nanoparticles. Herein, we aim to review the scientific progress and perspectives for polymer-based nanoparticles as drug delivery systems for purines. Polymeric nanoparticles turned out to have the potential to augment antiviral and antiproliferative effects of purine derivatives by specific binding to receptors (ASGR1-liver, macrophage mannose receptor), increase in drug retention (in eye, intestines, and vagina), and permeation (intranasal to brain delivery, PEPT1 transport of acyclovir). The most significant achievements of polymer-based nanoparticles as drug delivery systems for purines were found for tenofovir disoproxil in protection against HIV, for acyclovir against HSV, for 6-mercaptopurine in prolongation of mice ALL model life, as well as for 6-thioguanine for increased efficacy of adoptively transferred T cells. Moreover, nanocarriers were able to diminish the toxic effects of acyclovir, didanosine, cladribine, tenofovir, 6-mercaptopurine, and 6-thioguanine.

The Impact of Systemic Medications on Retinal Function

This study will provide a thorough review of systemic (and select intravitreal) medications, along with illicit drugs that are capable of causing various patterns of retinal toxicity. The diagnosis is established by taking a thorough medication and drug history, and then by pattern recognition of the clinical retinal changes and multimodal imaging features. Examples of all of these types of toxicity will be thoroughly reviewed, including agents that cause retinal pigment epithelial disruption (hydroxychloroquine, thioridazine, pentosan polysulfate sodium, dideoxyinosine), retinal vascular occlusion (quinine, oral contraceptives), cystoid macular edema/retinal edema (nicotinic acid, sulfa-containing medications, taxels, glitazones), crystalline deposition (tamoxifen, canthaxanthin, methoxyflurane), uveitis, miscellaneous, and subjective visual symptoms (digoxin, sildenafil). The impact of newer chemotherapeutics and immunotherapeutics (tyrosine kinase inhibitor, mitogen-activated protein kinase kinase, checkpoint, anaplastic lymphoma kinase, extracellular signal-regulated kinase inhibitors, and others), will also be thoroughly reviewed. The mechanism of action will be explored in detail when known. When applicable, preventive measures will be discussed, and treatment will be reviewed. Illicit drugs (cannabinoids, cocaine, heroin, methamphetamine, alkyl nitrite), will also be reviewed in terms of the potential impact on retinal function.

Didanosine-induced Retinopathy: New Insights with Long-term Follow-up

INTRODUCTION

Didanosine is an adenosine analog, part of the nucleoside reverse-transcriptase inhibitor family. Since the description of didanosine-induced retinopathy in the early 1990s, little is known about the progression of this toxic retinopathy and the putative underlying mitochondrial defect.

OBJECTIVES

We report long-term follow-up for cases of didanosine-induced retinopathy and discuss a new hypothesis for pathophysiology based on the alteration of endogenous adenosine on the photoreceptor outer segment turnover and phagocytosis by the retinal pigment epithelium.

METHODS

Ophthalmic data from six cases (12 eyes) of didanosine-induced retinopathy from a single institution were retrospectively analyzed.

RESULTS

All patients displayed bilateral retinal alterations in the mid-periphery. Despite didanosine discontinuation, patients with advanced areas of patchy chorioretinal atrophy appeared to have a faster progression than those with limited lesions. Full-field electroretinogram revealed generalized rod-cone dysfunction in most cases that remained stable over time.

CONCLUSION

We propose new guidelines including early screening and long-term observations.

A Rare Case of Didanosine-Induced Mid-Peripheral Chorioretinal Atrophy Identified Incidentally 11 Years after the Drug Cessation

Objective: This article aims to describe a unique case of didanosine-induced retinal degeneration that was discovered 11 years after the drug withdrawal. Case report: The patient is a 42-year-old woman with a medical history of HIV and hepatitis C virus since 2004. She has been prescribed antiretroviral therapy since then. For the first seven years (2004–2011), the patient was prescribed a combination therapy consisting of didanosine, efavirenz, and lamivudine. The protocol was changed to atripla (efavirenz, emtricitabine, and tenofovir) from 2011 to 2021. Recently (October 2021–January 2021), the patient was prescribed eviplera (rilpivirin, emtricitabine, and tenofovir). In addition, her past medical history revealed Gougerot-Sjogren syndrome and rheumatoid arthritis. She was prescribed hydroxychloroquine (HCQ) (2009–2021) at a dose of 400 mg daily. She had no vision complaint. Results: During her routine HCQ screening at the eye clinic, University Hospital Bretonneau, Tours, France, the widefield colour fundus photograph showed well-defined symmetric mid-peripheral areas of chorioretinal atrophy sparing the posterior pole of both eyes. Furthermore, the widefield fundus autofluorescence illustrated mid-peripheral round well-demarcation hypoautofluorescent areas of chorioretinal atrophy of both eyes. Conversely, the macular optical coherence tomography (OCT) was normal. Many of her drugs are known to be associated with retinopathy such as HCQ, tenofovir, efavirenz, and didanosine. Because our data corroborate peripheral retinal damage rather than posterior pole damage, this case report is compatible with didanosine-induced retinopathy rather than HCQ, efavirenz, or tenofovir retinal toxicity. Conclusions: All HIV patients who are presently or were previously on didanosine therapy should have their fundus examined utilising widefield fundus autofluorescence and photography.

Update on Retinal Drug Toxicities

Purpose of Review

This review aims to provide an update on the clinical presentations and diagnostic findings of drug-induced retinal toxicities.

Recent Findings

Several newly FDA-approved medications have been associated with acute retinal toxicities, including brolucizumab, MEK inhibitors, ulixertinib, and FGFR inhibitors. Additionally, as previously believed-to-be well-tolerated medications, such as pentosan sulfate sodium, anti-retroviral therapies, and certain intraoperative ocular medications, are used more frequently or for longer periods of time, associated toxic retinopathies and inflammatory reactions have been reported. Finally, advances in ocular imaging have revealed novel findings in hydroxychloroquine and tamoxifen maculopathies.

Summary

Discovery of new medications, increased frequency of use, and longer-term use have led to increased reports of retinal toxicities. Advances in retinal imaging have allowed for earlier detection of subclinical changes associated with these medications, which may help prevent progression of disease. However, more research is needed to determine the point at which vision loss becomes irreversible. Risks and benefits must be assessed prior to discontinuation of the offending, but potentially lifesaving, therapy.

Protection of Retinal Function by Nucleoside Reverse Transcriptase Inhibitors Following Retinal Ischemia/Reperfusion Injury

Purpose: Retinal ischemia/reperfusion (I/R) injury is a common cause of visual impairment and blindness for which there remain limited treatment options. Nucleoside reverse transcriptase inhibitors (NRTIs), such as zidovudine (AZT), have been shown to block the NLRP3 inflammasome and prevent retinal degeneration in a mouse model of age-related macular degeneration. The NLRP3 inflammasome has also been shown to be triggered in I/R injury. Therefore, we studied the neuroprotective effects of AZT using a pressure-induced retinal ischemia mouse model. Methods: C57BL/6J mice were randomly assigned to 1 of 2 treatment groups: vehicle-treated retinal I/R injury (n = 6) or AZT-treated retinal I/R injury (n = 6). Vehicle (1% dimethyl sulfoxide [DMSO] in phosphate-buffered saline [PBS]) or AZT 50 mg/kg in 1% DMSO in PBS were injected intraperitoneally twice daily for 5 days. On day 2 of treatment, retinal ischemia was induced by transient elevation of intraocular pressure for 45 min. Scotopic electroretinography (ERG) was used to quantify retinal function before and 1 week after retinal ischemic insult. Retinal morphology was examined 1 week after ischemic insult. Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assays and caspase 1 immunostaining was performed 24 h after retinal I/R injury. Results: Following I/R injury, ERG a- and b-wave amplitudes were significantly reduced in the vehicle-treated mice. AZT treatment significantly attenuated I/R-induced loss of retinal function as compared with vehicle-treated mice. Additionally, AZT-treated mice experienced significantly less inner retinal thinning as compared with vehicle-treated mice. TUNEL-positive cells were prevalent in the vehicle-treated I/R injury mouse retinas compared with the AZT-treated I/R injury mouse retinas. More caspase-1 immunoreactivity was detected in ganglion cell layer and inner nuclear layer (INL) in vehicle-treated I/R injury group than in AZT-treated I/R injury group. Conclusion: AZT treatment resulted in relative preservation of retinal structure and function following ischemic insult as compared with controls. This suggests AZT may have therapeutic value in the management of retinal ischemic diseases.

Case Report: Multimodal Imaging of Toxic Retinopathies Related to Human Immunodeficiency Virus Antiretroviral Therapies: Maculopathy vs. Peripheral Retinopathy. Report of Two Cases and Review of the Literature

Purpose: We report two patients with toxic retinopathy from either ritonavir or didanosine and reviewed the literature on the topics. We provide an overview of the retinal toxicity of these two antiretroviral drugs in human immunodeficiency virus-positive patients.

Methods: First, we performed a retrospective study of the medical charts of two patients examined by us, one with ritonavir maculopathy and one with didanosine peripheral retinopathy. Secondly, we searched the world literature for similar cases through PubMed and Google Scholar, using the terms “HIV,” “AIDS,” “ritonavir,” “didanosine,” “maculopathy,” “retinopathy,” “visual loss,” and “toxicity” to retrieve the appropriate literature on the subject.

Results: Patient 1: A 49-year-old woman complained of progressive central visual loss over the past 12 months. History disclosed ongoing ritonavir therapy for the past 11 years. Ritonavir maculopathy was diagnosed, and visual loss increased relentlessly despite cessation of treatment. Patient 2: A 55-year-old man complained of slowly progressive peripheral visual field constriction for the past 5 years. History disclosed didanosine therapy for 13 years, however, stopped 4 years before the onset of visual symptoms. No alteration of therapy was offered to patient 2 as didanosine therapy was interrupted 9 years previously. Since 2011, 11 cases of ritonavir maculopathy have been reported in the literature. Relentless worsening of vision was reported in 3/7 patients despite cessation of ritonavir therapy. Didonasine peripheral retinopathy was first described in 1992, and a total of 24 patients have been reported since. Relentlessly progressive peripheral retinopathy was diagnosed despite the previous cessation of therapy in 14 patients.

Conclusion: Ritonavir causes a slowly progressive atrophic maculopathy, and didanosine toxicity results in a relentlessly progressing peripheral atrophic retinopathy. The relentless progression of both toxic retinopathies reflects permanent alterations of the retinal metabolism by these medications. Both ritonavir and didanosine toxic retinopathies are rare events, but their clinical presentation is highly specific.

Ocular Side Effects of Common Systemic Medications and Systemic Side Effects of Ocular Medications

When prescribing medications, it is important to consider the ocular side effects of common systemic therapy as well as potential systemic side effects of ocular medications. Although not an exhaustive list of medications/classes of medications, this article does include many commonly used drugs and also provides information on some topical therapies commonly used by ophthalmologists. These ocular medications may result in systemic effects and/or alter patients' management of systemic conditions.

MULTIMODAL IMAGING IN DIDANOSINE RETINOPATHY

PURPOSE

To present the multimodal retinal imaging findings in didanosine retinopathy in a patient who presented 6.5 years after stopping the use of didanosine and to highlight the absence of progression during a 1.5-year follow-up.

METHODS

Case report involving clinical examination, fundus photography, fundus autofluorescence, fluorescein angiography, optical coherence tomography, Goldmann kinetic perimetry, and full-field electroretinography.

RESULTS

A 52-year-old patient presented with bilateral retinopathy 6.5 years after stopping didanosine having used the medication for 8.5 years. Fundus examination showed a ring-shaped zone of atrophy of the retinal pigment epithelium involving the midperiphery. On autofluorescence imaging, there was diffuse hypoautofluorescence involving the midperipheral retina in both eyes. On fluorescein angiography, there was a granular mottled pattern of diffuse hyperfluorescence in the midperiphery in both eyes, with baring of the large choroidal vessels in some areas. On Goldmann kinetic perimetry, both eyes showed marked constriction of the isopter to the I4e stimulus, and there was a temporal scotoma to the III4e target in both eyes. Full-field electroretinography showed generalized rod and cone photoreceptor dysfunction in both eyes. During a follow-up for 1.5 years, there was no evidence of progression.

CONCLUSION

Patients who have used didanosine should be evaluated for the presence of retinopathy, which involves the midperipheral retina.

CHM mutation spectrum and disease: An update at the time of human therapeutic trials

Choroideremia is an X-linked inherited retinal disorder (IRD) characterized by the degeneration of retinal pigment epithelium, photoreceptors, choriocapillaris and choroid affecting males with variable phenotypes in female carriers. Unlike other IRD, characterized by a large clinical and genetic heterogeneity, choroideremia shows a specific phenotype with causative mutations in only one gene, CHM. Ongoing gene replacement trials raise further interests in this disorder. We describe here the clinical and genetic data from a French cohort of 45 families, 25 of which carry novel variants, in the context of 822 previously reported choroideremia families. Most of the variants represent loss-of-function mutations with eleven families having large (i.e. ≥6 kb) genomic deletions, 18 small insertions, deletions or insertion deletions, six showing nonsense variants, eight splice site variants and two missense variants likely to affect splicing. Similarly, 822 previously published families carry mostly loss-of-function variants. Recurrent variants are observed worldwide, some of which linked to a common ancestor, others arisen independently in specific CHM regions prone to mutations. Since all exons of CHM may harbor variants, Sanger sequencing combined with quantitative polymerase chain reaction or multiplex ligation-dependent probe amplification experiments are efficient to achieve the molecular diagnosis in patients with typical choroideremia features.

Ritonavir associated maculopathy- multimodal imaging and electrophysiology findings

Purpose

To report the case 47-year-old patient presenting with severe maculopathy associated with long-term ritonavir treatment.

Methods

Observational case report of one patient and literature review.

Results

A 47 year-old Caucasian man presented with progressive bilateral vision loss for the past 5 years. His medical history included Human Immunodeficiency Virus (HIV) and Hepatitis C Virus (HCV) coinfection since 1992. He was treated by highly active antiretroviral therapy for 24 years including 4 years of didanosine treatment and 18 years of ritonavir treatment. Bilateral extensive macular atrophy with foveal sparing on the left eye and absence of midperipheral/peripheral retina involvement was confirmed on multimodal imaging and functional testing including swept-source OCT angiography and electroretinography.

Conclusion

Ritonavir associated maculopathy is a scarcely described medication-associated retinopathy. In this case, an extensive macular atrophy (with complete loss of photoreceptor, RPE and choriocapillaris layers) and subsequent cone-rod dysfunction appeared after 18 years of ritonavir exposure.

Case Report: Retinal Toxicity Secondary to Ritonavir

SIGNIFICANCE

Because patients with HIV have increased life expectancies with the advent of new drug therapies, complications from iatrogenic syndromes such as drug toxicity can occur. Ritonavir-induced retinal toxicity is one such complication but has rarely been reported in the literature.

PURPOSE

This case report describes a patient with bilateral maculopathy and bone spicule-like pigmentary changes in the midperipheral retina due to ritonavir use. In addition, novel optical coherence tomography findings are described.

CASE REPORT

A 53-year-old man presented with gradual-onset blurry vision and difficulty seeing at night. He had been diagnosed as having HIV infection 19 years prior and had previously taken ritonavir for 7 years as part of highly active antiretroviral therapy. Best-corrected acuities were 20/30 in the right eye and 20/25 in the left eye. Clinical examination revealed a subtle annular pattern of retinal pigment epithelium mottling around the fovea and bone spicule-like pigment changes in the midperiphery of both retinas. Optical coherence tomography imaging revealed abnormal subfoveal hyperreflectivity of the ellipsoid zone with relative attenuation centrally, annular parafoveal ellipsoid zone loss, and punctate hyperreflectivity within the ellipsoid zone more eccentrically. Fundus autofluorescence in both eyes showed annular hyperautofluorescence in the parafoveal region, geographic hyperautofluorescence in the areas underlying the midperipheral pigmentary changes, and discrete patches of hyperautofluorescence along the far inferotemporal arcades in areas that appeared normal with biomicroscopy. A diagnosis of retinal toxicity secondary to ritonavir use was made based on the patient's history and clinical examination.

CONCLUSIONS

Ritonavir retinal toxicity seems to be an uncommon adverse event that can cause decreased visual function. This case report provides further evidence of the retinal toxicity and reviews the reported clinical and optical coherence tomography manifestations of the disease.

Wide field retinal imaging and the detection of drug associated retinal toxicity

Background

To describe the peripheral retinal findings associated with systemic medication toxicity and to outline the importance of ultra-widefield imaging in the detection, analysis and monitoring of these abnormalities.

Main text

This review highlights the retinal manifestations associated with the more common drug toxicities, with emphasis on the peripheral features and the indications for wide field imaging. The presenting findings, underlying pathophysiology, and retinal alterations in hydroxychloroquine, thioridazine, didanosine, tamoxifen, MEK-inhibitor, and immune checkpoint inhibitor associated drug toxicity will be described and the importance of wide field imaging in the evaluation of these abnormalities will be emphasized.

Conclusions

Wide field retinal imaging can improve the detection of peripheral retinal abnormalities associated with drug toxicity and may be an important tool in the diagnosis and management of these disorders.