Treatment of recurrent cytomegalovirus retinitis with the ganciclovir implant

Clinical features of Cytomegalovirus retinitis in patients with acquired immunodeficiency syndrome and efficacy of the current therapy

Background

Cytomegalovirus retinitis (CMVR) is the most common and sight-threatening opportunistic retinal infection in patients with acquired immunodeficiency syndrome (AIDS) and several controversies remain to be settled. We aimed to summarize the current evidence and clarify the clinical features and prognosis of CMVR in AIDS patients.

Methods

The databases PubMed, EMBASE, and Ovid from inception to April 2022 were searched to identify the relevant studies. R software version 3.6.3 was used to perform the statistical analyses. Results in proportion with 95% confidence interval (CI) were calculated using the Freeman-Tukey variant of arcsine square transformation.

Results

We finally included 236 studies comprising 20,214 patients. CMVR in AIDS was male-dominated (88%, 95%CI 86%-89%), with 57% (95%CI 55%-60%) aged <41 years and 44% (95%CI 41%-47%) being bilaterally involved. CMVR was preponderant in AIDS patients with the following characteristics: white and non-Hispanic, homosexual, HIV RNA load ≥ 400 copies/mL, and CD4+ T-cells <50 cells/μL. The positivity of CMV-DNA in blood, aqueous humor, and vitreous humor was 66% (95%CI 52%-79%), 87% (95%CI 76%-96%), and 95% (95%CI 85%-100%), respectively. The most common symptoms were blurred vision (55%, 95%CI 46%-65%), followed by asymptomatic, visual field defect, and floaters. CMVR was first diagnosed and regarded as the clue to AIDS diagnosis in 9% (95%CI 6%-13%) of CMVR patients. Approximately 85% (95%CI 76%-93%) of the CMVR patients have received cART. CMVR remission was observed in 72%-92% of patients depending on the specific category of anti-CMV therapy. The general incidence of CMVR-related RD in the entire course was 24% (95%CI 18%-29%), of which most patients received PPV with SO or gas tamponade and the rate of anatomic success was 89% (95%CI 85%-93%).

Conclusion

CMVR is a common opportunistic infection with diverse clinical features in AIDS patients, preponderant in those who are male, homosexual, or with CD4+ T-cells <50 cells/μL. Current therapies for CMVR and CMVR-related RD were shown to be effective. Early detection and routine ophthalmic screening should be promoted in AIDS patients.

Systematic review registration

PROSPERO, identifier CRD42022363105.

Applications of polymers in intraocular drug delivery systems

We are entering a new era of ophthalmic pharmacology where new drugs are rapidly being developed for the treatment of anterior and posterior segment of the eye disease. The pharmacokinetics of drug delivery to the eye remains a very active area of ophthalmic research. Intraocular drug delivery systems allow the release of the drug, bypassing the blood-ocular barrier. The main advantage of these preparations is that they can release the drug over a long time with one single administration. These pharmaceutical systems are of great important in the treatment of the posterior segment diseases, and they can be prepared from biodegradable or nonbiodegradable polymers. Biodegradable polymers have the advantage of disappearing from the site of action after releasing the drug. The majority of intraocular devices are prepared from nonbiodegradable polymers, and they can release controlled amounts of drugs for months. Nonbiodegradable polymers include silicone, polyvinyl alcohol, and ethylene-vinyl acetate. The polymers usually employed to prepare nanoparticles for the topical ophthalmic route are poly (acrylic acid) derivatives (polyalquilcyanocrylates), albumin, poly-ε-caprolactone, and chitosan. Dendrimers are a recent class of polymeric materials with unique nanostructure which has been studied to discover their role in the delivery of therapeutics and imaging agents. Hydrogels are polymers that can swell in aqueous solvent system, and they hold the solvents in a swollen cross-linked gel for delivery. This review exhibits the current literature regarding applications of polymers in ophthalmic drug delivery systems including pharmacokinetics, advantages, disadvantages, and indications aimed to obtain successful eye therapy.

Pathogenesis and treatment of human immunodeficiency virus-associated cytomegalovirus retinitis

In the era of HAART, human cytomegalovirus (HCMV) retinitis remains the leading opportunistic ocular infection and the major cause of blindness in patients with AIDS. The virus has been subjected to selection and presented with the opportunity to occupy a niche to which it is highly adapted in order to escape from host immune recognition and establish persistent infection in the retina. The imbalance between host immune protection and viral immune evasion results in retinitis progression. Moreover, a synergistic interaction between HCMV and HIV in the pathogenesis of retinitis has been proposed. HAART has had a major beneficial impact on the prognosis for HIV-infected individuals. Both HAART and specific anti-HCMV treatment contribute to therapeutic success against HCMV retinitis in AIDS patients. The improved prognosis for AIDS patients with respect to the development of HCMV retinitis has been welcomed; however, we should bear in mind the occurrence of HIV drug resistance, relapse of retinitis and immune recovery uveitis after treatment, which mean that this complication of HIV infection remains a threat.

Ganciclovir implant in the treatment of cytomegalovirus retinitis

The ganciclovir implant is a sustained-release intraocular drug delivery system used to treat cytomegalovirus retinitis that provides a high and steady-state concentration of the drug in the vitreous cavity over a period of 7-8 months. Randomized, controlled clinical trials have demonstrated a superior efficacy of the implant compared with intravenous ganciclovir. Severe adverse events associated with the implant are uncommon, though potentially blinding. In addition, the implant provides no protection against second-eye or visceral cytomegalovirus retinitis infections. This review summarizes the clinical indications for and complications associated with the ganciclovir implant.

Ocular association of HIV infection in the era of highly active antiretroviral therapy and the global perspective

Ocular involvement is a common complication of HIV infection. Since the late 1990s, widespread use of highly active antiretroviral therapy (HAART) has altered the spectrum, and reduced the incidence of ocular involvement in developed countries. The incidence of the most common ocular opportunistic infection, cytomegalovirus retinitis, has decreased tremendously. However, immune recovery uveitis secondary to HAART has emerged as a frequent visually threatening condition. Early diagnosis and treatment with periocular steroids is helpful in minimizing visual loss. Clinicians should also be aware that certain antimicrobial agents used to treat opportunistic infections in HIV-positive patients are associated with potentially serious ocular side effects. In developing countries, where most of the world's 40 million HIV-positive patients live, the spectrum and incidence of ocular involvement differ from those in developed countries. The lack of HAART availability is among the many causes of these differences, which may include nutritional factors, basic medical care availability and the levels of exposure to different infectious agents. These factors add to the already challenging task of treating ocular complications and preventing blindness in HIV-positive patients in developing countries.

Complications of ganciclovir implant surgery in patients with cytomegalovirus retinitis: the Ganciclovir Cidofovir Cytomegalovirus Retinitis Trial

PURPOSE

To describe the complications of ganciclovir implant surgery in patients with cytomegalovirus retinitis.

METHODS

Prospective data collection within the context of a randomized, controlled clinical trial, comparing a regimen of the ganciclovir implant plus oral ganciclovir to one of intravenous cidofovir for the treatment of cytomegalovirus retinitis in patients with AIDS. Adverse events were compared for patients undergoing implant surgery in the following groups: primary versus replacement implant surgery, inpatient versus outpatient surgery, and general versus local anesthesia.

RESULTS

Fifty-six eyes of 42 patients underwent a total of 74 ganciclovir implant surgeries. Vitreous hemorrhage was the most common adverse event, occurring in 10% of eyes undergoing surgery with local anesthesia but in no eyes undergoing surgery with general anesthesia. All vitreous hemorrhages resolved within 60 days. Patients in the general anesthesia and inpatient surgery groups tended to have a lower risk of complications in the first 30 days than did patients in the local anesthesia and outpatient surgery groups, but no differences in the complication rate were found after 60 days. Visual acuity was similar among these different groups. There were no cases of endophthalmitis.

CONCLUSION

Ganciclovir implant surgery in patients with AIDS and cytomegalovirus retinitis was associated with a low risk of serious complications in the first 60 days after surgery. Vitreous hemorrhage was the most commonly observed complication and resolved in all cases.

Posterior segment manifestations of HIV/AIDS

The ocular posterior segment manifestations of AIDS may be divided into four categories: retinal vasculopathy, unusual malignancies, neuro-ophthalmologic abnormalities, and opportunistic infections. Microvasculopathy is the most common manifestation. Opportunistic infections, particularly cytomegalovirus retinitis and progressive outer retinal necrosis, are the most likely to result in visual loss due to infection or subsequent retinal detachment. Diagnosis and treatment are guided by the particular conditions and immune status of the patient.

Genotypic analysis of cytomegalovirus retinitis poorly responsive to intravenous ganciclovir but responsive to the ganciclovir implant

PURPOSE

To determine whether cytomegalovirus (CMV) retinitis that responded poorly to intravenous ganciclovir therapy but responded to the ganciclovir implant was caused by virus with resistance mutations in the viral UL97 and UL54 genes.

DESIGN

Retrospective chart review and laboratory-based experimental study.

METHODS

Regions of the CMV UL97 and UL54 were amplified from the vitreous and analyzed for resistant mutations by a combination of DNA sequencing and restriction digestion. Vitreous from patients with AIDS and retinal infections other than CMV retinitis served as negative controls.

RESULTS

We amplified all target regions of UL97 DNA and most target regions of UL54 DNA from eight eyes with CMV retinitis. In one eye we found a ganciclovir resistance mutation at base 1781 of the UL97 gene, predicting an alanine to valine mutation at codon 594. In a second eye we found a ganciclovir resistance mutation at base 2960 of the UL54 gene, predicting an alanine to glycine mutation at codon 987. In two additional eyes, both from patients with bilateral retinitis, we found UL54 mutations that are likely to confer resistance to ganciclovir but have not been previously described. In both of these patients the UL54 genotype differed between the two diseased eyes.

CONCLUSIONS

Failure to control CMV retinitis with intravenous ganciclovir does not necessarily imply infection with a virus having a known mutation that confers drug resistance. The ganciclovir implant can be an effective therapy for CMV retinitis caused by virus with certain UL97 and UL54 resistance mutations. Cytomegalovirus UL54 genotypes can differ between eyes in patients with bilateral retinitis.

Therapy and Prevention of Cytomegalovirus Retinitis

Highly active antiretroviral therapy (HAART) has redefined the natural history of cytomegalovirus (CMV) retinitis. Once a major cause of blindness in AIDS patients, its incidence has plummeted and its clinical course has been altered. The potential of HAART for immunologic restoration should guide treatment decisions, and may ultimately lead to the possibility of withdrawal from maintenance anti-CMV therapy. However, new cases of CMV retinitis have begun to emerge in virologic and immunologic failures to HAART. The impact of HAART continues to evolve with the discovery of sight-threatening immune recovery uveitis. Specific anti-CMV treatment strategies have expanded and improved to include therapeutic options not requiring the parenteral route of administration such as valganciclovir, which has enhanced oral bioavailability.

Changing therapeutic paradigms in CMV retinitis in AIDS

Cytomegalovirus (CMV) retinitis is a common ocular complication of immunosuppression. The management of CMV retinitis has been continuously evolving over the last decade. The mainstay of therapy remains ganciclovir and foscarnet. However, increasing resistance and ongoing toxicities to these agents remain a challenge. Additional frequently utilised agents include cidofovir and fomivirsen. The advent of highly active antiretroviral therapy (HAART) has allowed the restoration of immunocompetency to many patients previously challenged by CMV infection. In some circumstances, HAART has even eliminated the need for ongoing antiviral therapy. This paper reviews the current treatment modalities, including their toxicities and dosing recommendations.

Effect of potent antiretroviral therapy on recurrent cytomegalovirus retinitis treated with the ganciclovir implant

PURPOSE

To determine the effect of highly active antiretroviral therapy on cytomegalovirus (CMV) retinitis treated with ganciclovir implants.

METHODS

A retrospective cohort study was performed of 15 patients with recurrent CMV retinitis treated with the ganciclovir implant and highly active antiretroviral therapy (cases) and 38 patients with recurrent retinitis treated with ganciclovir implants before availability of improved antiretroviral therapy (controls). Progression was defined as occurrence of new lesions in the treated eye or advancement of the retinitis border by more than 750 microm.

RESULTS

Cases and controls were statistically similar in age, ethnicity, and duration of acquired immunodeficiency syndrome (AIDS). Controls had received intravenous ganciclovir for 9.5 +/- 9.5 months vs 3.5 +/- 4.6 months in cases (P = .003). The mean (+/- SE) time to progression of retinitis after implantation of the device was 26.7 +/- 2.4 months (95% confidence interval, 22.1 to 31.3) in the cases receiving highly active antiretroviral therapy vs 6.2 +/- 0.9 months (95% confidence interval, 4.5 to 7.9) in the controls (P = .001). Multivariate analysis, adjusted for preoperative variables, confirmed a significantly prolonged time to progression in patients receiving highly active antiretroviral therapy (P = .0003). The odds ratio for progression in the cases vs controls was 0.034 (95% confidence interval, 0.003 to 0.350). Cases had higher CD4+ T-lymphocyte counts (P = .004) and longer survival (P < .001) than controls.

CONCLUSION

Highly active antiretroviral therapy is associated with improved outcomes in patients with AIDS and recurrent CMV retinitis treated with the ganciclovir implant.