Phase I/II study of intravitreal cidofovir for the treatment of cytomegalovirus retinitis in patients with the acquired immunodeficiency syndrome

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.

Drug-induced Uveitis in HIV Patients with Ocular Opportunistic Infections

Purpose: To describe drug-induced uveitis in immunocompromised patients diagnosed with Human Immunodeficiency Virus (HIV) infection Methods: Narrative Review Results: Systemic and intraocular medications administered for the treatment of acquired immune deficiency syndrome (AIDS)-associated diseases in patients infected with HIV are a well-known cause of uveitis. Conclusions: Cidofovir and rifabutin, among other novel anti-retroviral therapies, are strongly associated with drug-induced uveitis. It is imperative to understand the pathogenesis, clinical findings, and management of HIV patients with uveitis induced by these agents.

Ocular hypotony: A comprehensive review

Ocular hypotony is an infrequent, yet potentially vision-threatening, entity. The list of differential causes is extensive, involving any condition that may compromise aqueous humor dynamics or the integrity of the globe and sometimes following medical treatments or procedures. Depending on the cause and the clinical impact, treatment options aim to correct the underlying pathology and to reestablish anatomical integrity, as well as visual function. We review the pathophysiology, clinical presentation, different causes, and associated therapeutic options of ocular hypotony.

HPMPC (cidofovir), PMEA (adefovir) and Related Acyclic Nucleoside Phosphonate Analogues: A Review of their Pharmacology and Clinical Potential in the Treatment of Viral Infections

The acyclic nucleoside phosphonate (ANP) analogues are broad-spectrum antiviral agents, with potent and selective antiviral activity in vitro and in vivo. The prototype compounds are: ( S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine (HPMPC, cidofovir), which is active against a wide variety of DNA viruses; 9-(2-phosphonylmethoxyethyl)adenine (PMEA, adefovir), which is active against retro-, herpes- and hepadnaviruses, and ( R)-9-(2-phosphonylmethoxypropyl) adenine (PMPA), which is active against retro- and hepadnaviruses. The antiviral action of the ANP analogues is based on a specific interaction of the active diphosphorylated metabolite with the viral DNA polymerase. The long intracellular half-life of the active metabolite accounts for the optimal efficacy in infrequent dosing schedules. The potential of HPMPC as a broad-spectrum anti-DNA virus agent, as originally observed in vitro and in vivo, has been confirmed in clinical trials. HPMPC has recently been commercially released in the USA for the treatment of cytomegalovirus retinitis in AIDS patients. In addition, topical systemic HPMPC is being (or will be) explored for use against other herpesviruses (i.e. herpes simplex virus, Epstein-Barr virus, or varicella-zoster virus), by adenoviruses, or by human papilloma- or polyomaviruses. Intravenous HPMPC is associated with dose-dependent nephrotoxicity, that should be counteracted by prehydration and concomitant administration of probenecid, and by the application of an infrequent dosing schedule. The oral prodrug of PMEA, bis(pivaloyloxymethyl)-PMEA, is currently being evaluated in patients infected with human immunodeficiency virus (HIV) or hepatitis B virus. Finally, preclinical data on the efficacy of PMPA in animal retrovirus models point to its potential usefulness against HIV infections, when given either prophylactically or therapeutically in the treatment of established HIV infections.

Drug-induced uveitis

INTRODUCTION

Drug-induced uveitis is a well described but often overlooked and/or misdiagnosed adverse reaction to medication. There are an increasing number of medications that have been related to the onset of intraocular inflammation. Identification of these inciting agents may decisively help the diagnostic algorithm involving new cases of uveitis.

AREAS COVERED

This review intends to be an updated comprehensive, practical guide for practitioners regarding the main drugs that have been associated with uveitis. A classification proposed by Naranjo et al. in 1981 for establishing potential causality is applied examining possible mechanisms of action. A guide for clinicians about the rationale of these observations when dealing with patients with uveitis is provided.

EXPERT OPINION

Several agents with different routes of administration (systemic, topical and/or intraocular) may cause intraocular inflammation. The mechanism behind ocular inflammation is frequently unknown. Clinicians should be aware of the potential drug effect to optimize diagnosis and management of such patients.

Drug-induced uveitis

A number of medications have been associated with uveitis. This review highlights both well-established and recently reported systemic, topical, intraocular, and vaccine-associated causes of drug-induced uveitis, and assigns a quantitative score to each medication based upon criteria originally described by Naranjo and associates.

Recent developments in the treatment of posterior uveitis

Uveitis is an intraocular inflammation that can be caused by infection, autoimmune disease, trauma or malignancy. It is a serious cause of visual handicap and therapy is targeted at: removal of possible infectious agents, the immunological processes that lead to or sustain the inflammation and finally to prevent or treat the destructive effects of the inflammation on the delicate ocular structures. In this review the latest developments concerning the treatment of posterior uveitis are illuminated, e. g., new approaches concerning the treatment of infectious uveitis including the therapy of herpes virus (VZV, HSV and CMV), bacterial and toxoplasma infections of the eye. Several new ways to influence the immune response and inflammation are described including the use of interferons, modulation of cytokines, soft steroids, other new immunosuppressive drugs and treatment of autoimmune uveitis by oral tolerization. An overview is given to illustrate new ways to administer drugs into eyes, such as intravitreal devices. Finally new developments in the field of the treatment of the various complications of uveitis (cystoid macular edema) are described.

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.

Intravitreal injection of therapeutic agents

BACKGROUND

Intravitreal injection (IVI) with administration of various pharmacological agents is a mainstay of treatment in ophthalmology for endopthalmitis, viral retinitis, age-related macular degeneration, cystoid macular edema, diabetic retinopathy, uveitis, vascular occlusions, and retinal detachment. The indications and therapeutic agents are reviewed in this study.

METHODS

A search of the English, German, and Spanish language MEDLINE database was conducted. A total of 654 references spanning the period through early 2008 were individually evaluated.

RESULTS

The advantage of the IVI technique is the ability to maximize intraocular levels of medications and to avoid the toxicities associated with systemic treatment. Intravitreal injection has been used to deliver several types of pharmacological agents into the vitreous cavity: antiinfective and antiinflammatory medications, immunomodulators, anticancer agents, gas, antivascular endothelial growth factor, and several others. The goal of this review is to provide a detailed description of the properties of numerous therapeutic agents that can be delivered through IVI, potential complications of the technique, and recommendations to avoid side effects.

CONCLUSION

The IVI technique is a valuable tool that can be tailored to the disease process of interest based on the pharmacological agent selected. This review provides the reader with a comprehensive summary of the IVI technique and its multitude of uses.

HIV-associated retinopathy in the HAART era

BACKGROUND

The effectiveness of highly active antiretroviral therapy (HAART) in restoring immune function in patients with acquired immunodeficiency syndrome (AIDS) has led to changes in the incidence, natural history, management, and sequelae of human immunodeficiency virus (HIV)-associated retinopathies, especially cytomegalovirus (CMV) retinitis.

METHODS

The medical literature pertaining to HIV-associated retinopathies was reviewed with special attention to the differences in incidence, management strategies, and complications of these conditions in the eras both before and after the widespread use of HAART.

RESULTS

In the pre-HAART era, CMV retinitis was the most common HIV-associated retinopathy, occurring in 20%-40% of patients. Median time to progression was 47 to 104 days, mean survival after diagnosis was 6 to 10 months, and indefinite intravenous maintenance therapy was mandatory. Retinal detachment occurred in 24%-50% of patients annually. Herpetic retinopathy and toxoplasmosis retinochoroiditis occurred in 1%-3% of patients and Pneumocystis carinii choroiditis, syphilitic retinitis, tuberculous choroiditis, cryptococcal choroiditis, and intraocular lymphoma occurred infrequently. In the HAART era the incidence of CMV retinitis has declined 80% and survival after diagnosis has increased to over 1 year. Immune recovery in patients on HAART has allowed safe discontinuation of maintenance therapy in patients with regressed CMV retinitis and other HIV-associated retinopathies. Immune recovery uveitis (IRU) is a HAART dependent inflammatory response that may occur in up to 63% of patients with regressed CMV retinitis and elevated CD4 counts and is associated with vision loss from epiretinal membrane, cataract, and cystoid macular edema.

CONCLUSIONS

The incidence, visual morbidity, and mortality of CMV retinitis and other HIV-associated retinopathies have decreased in the era of HAART and lifelong maintenance therapy may safely be discontinued in patients with restored immune function. Patients with regressed CMV retinitis, however, may still lose vision from epiretinal membrane, cystoid macular edema, and cataract secondary to IRU.

The relationship between AIDS retinal cotton wool spots and neuropsychological impairment in HIV-positive individuals in the pre-highly active antiretroviral therapy era

PURPOSE

To determine the relationship between AIDS retinal cotton wool spots (CWS) and neuropsychological impairment in HIV-positive individuals in the pre-HAART (highly active anti-retroviral therapy) era and the association between AIDS-related retinal CWS and neuropsychological impairment in HIV-positive patients not treated with HAART.

METHODS

A case-control analysis of prospectively acquired data in HIV-infected individuals who underwent prospective and longitudinal evaluations of retinal findings as well as neuropsychological testing was performed. Individuals underwent prospective retinal ophthalmic examinations with fundus photography of any retinal lesions. They also underwent periodic neuropsychological testing. The occurrence of retinal CWS was analyzed in relationship to neuropsychological impairment.

RESULTS

Thirty individuals with CWS were compared to 6o matched control AIDS patients. There was no association between either global clinical neuropsychological impairment or impairment in any of the five major domains tested and retinal CWS. There was an association between beta-2 microglobulin and CWS as well as an association between low CD4 T-cell count and the presence of retinal CWS.

CONCLUSIONS

We found no association between retinovascular disease and neurocognitive impairment in this case-control study. Retinal CWS in HIV disease are related to higher serum beta-2 microglobulin levels and lower CD4 T-cell counts, suggesting that these lesions are related to HIV disease progression but may be caused by a pathological process independent of CNS disease.

Clinical potential of the acyclic nucleoside phosphonates cidofovir, adefovir, and tenofovir in treatment of DNA virus and retrovirus infections

The acyclic nucleoside phosphonates HPMPC (cidofovir), PMEA (adefovir), and PMPA (tenofovir) have proved to be effective in vitro (cell culture systems) and in vivo (animal models and clinical studies) against a wide variety of DNA virus and retrovirus infections: cidofovir against herpesvirus (herpes simplex virus types 1 and 2 varicella-zoster virus, cytomegalovirus [CMV], Epstein-Barr virus, and human herpesviruses 6, 7, and 8), polyomavirus, papillomavirus, adenovirus, and poxvirus (variola virus, cowpox virus, vaccinia virus, molluscum contagiosum virus, and orf virus) infections; adefovir against herpesvirus, hepadnavirus (human hepatitis B virus), and retrovirus (human immunodeficiency virus types 1 [HIV-1] and 2 [HIV-2], simian immunodeficiency virus, and feline immunodeficiency virus) infections; and tenofovir against both hepadnavirus and retrovirus infections. Cidofovir (Vistide) has been officially approved for the treatment of CMV retinitis in AIDS patients, tenofovir disoproxil fumarate (Viread) has been approved for the treatment of HIV infections (i.e., AIDS), and adefovir dipivoxil (Hepsera) has been approved for the treatment of chronic hepatitis B. Nephrotoxicity is the dose-limiting side effect for cidofovir (Vistide) when used intravenously (5 mg/kg); no toxic side effects have been described for adefovir dipivoxil and tenofovir disoproxil fumarate, at the approved doses (Hepsera at 10 mg orally daily and Viread at 300 mg orally daily).

Synthesis of N-alkyl substituted indolocarbazoles as potent inhibitors of human cytomegalovirus replication

The synthesis and antiviral evaluation of unsymmetrical indolocarbazole derivatives of Arcyriaflavin A, substituted with a range of alkyl groups at the indole nitrogen, is described. Structure-activity relationships in this series against human cytomegalovirus (HCMV) replication in cell culture are reported. Compound 4b was identified as potent inhibitor of HCMV (IC(50)=19 nM), which retained activity against a range of HCMV strains including ganciclovir resistant isolates.

Comparative tolerability of therapies for cytomegalovirus retinitis

Cytomegalovirus (CMV) retinitis is a potentially sight-threatening complication of advanced HIV infection. The acute infection can be controlled with one of several therapies, including intravenous ganciclovir, foscarnet or cidofovir, slow release ganciclovir intraocular implants or serial intraocular injections of ganciclovir or foscarnet. The initial induction course of therapy is typically followed by lifelong maintenance therapy. In addition to the aforementioned treatments, oral ganciclovir and intravitreal fomivirsen injections are other options for maintenance therapy. The choice of agent must take into consideration factors such as comparative short and long term toxicity of the agents, route of administration and the possible need for indwelling catheters, administration time, cost and protection afforded against systemic dissemination of CMV infection. Possible drug interactions and additive toxicities of other agents needed for the management of the underlying HIV infection must also be taken into consideration. These factors can affect the tolerability of therapy as well as the quality of life of the patient. Relapse or progression of CMV retinitis may be caused by either inadequate drug concentrations at the site of the infection or by drug resistance. This may necessitate either an increase in drug dosage, a change in route of administration or a change to an alternative agent. All of these approaches can increase the risk of toxicity of the therapy. With the initiation of highly active antiretroviral therapy and partial reconstitution of the immune system, some patients have been able to successfully discontinue anti-CMV maintenance therapy, thereby decreasing long term drug toxicity. Determination of the patient predictors of success of this approach is an active area of research.

Intravitreal toxicology and therapeutic efficacy of the carboxymethyl ester of the 1-O-octadecyl-sn-glycerol-3-phosphonoformate (ODG-PFA-O-Me), a novel lipid antiviral prodrug for intraocular drug delivery

This study was conducted to evaluate the vitreous clarity and intraocular therapeutic index of three preparations ofthe carboxymethyl ester of 1-O-octadecyl-sn-glycerol-3-phosphonoformate (ODG-PFA-O-Me), a long acting lipid derivative of foscarnet with potent anti-CMV activity. Twenty-six New Zealand white rabbits were intravitreally injected with one of three preparations of ODG-PFA-O-Me or control diluent. The vitreous clarity was graded after injection using indirect ophthalmoscopy and fundus photography. Drug intraocular toxicity was evaluated by electroretinography and by post-sacrifice tissue pathology using light and electron microscopy. Intravitreal injection of micellar ODG-PFA-O-Me showed variable local retinal toxicity and vitreal compound aggregates in eyes with the middle and high doses. The intraocular therapeutic index was lower than 465:1. Intravitreal injection of liposomal ODG-PFA-O-Me, either free acid or sodium salt, revealed clear vitreous for the 0.632 and 0.84 mM final intravitreal concentrations. No retinal toxicity was confirmed for the 1.12 mM final intravitreal concentration at the eight week observation following injection. The intraocular therapeutic index was between 585-1037:1. ODG-PFA-O-Me possesses better vitreous compatibility than ODG-PFA. Liposomal ODG-PFA-O-Me can be intravitreally injected with a resulting clear vitreous and high intraocular therapeutic index. Liposomal ODG-PFA-O-Me could be a long acting nontoxic intravitreous injectable drug for CMV retinitis.

Cidofovir: a review of its use in cytomegalovirus retinitis in patients with AIDS

Cidofovir is an antiviral nucleotide analogue with significant activity against cytomegalovirus (CMV) and other herpesviruses. The drug is indicated for the treatment of CMV retinitis, a sight-threatening condition, in patients with AIDS. Cidofovir has a long intracellular half-life which allows for a prolonged interval (2 weeks) between maintenance doses. In contrast, other intravenous treatment options for patients with CMV retinitis (i.e. ganciclovir and foscarnet) must be administered on a daily basis. The efficacy of intravenous cidofovir has been demonstrated in patients with AIDS and previously untreated CMV retinitis in multicentre randomised trials, and in a dose-finding study of cidofovir in patients with AIDS and previously treated relapsing CMV retinitis. Clinical trials have been relatively small (n < or = 100 patients) and no studies have been conducted directly comparing intravenous cidofovir with the more established intravenous agents, ganciclovir or foscarnet. Indirect comparisons of clinical trial data suggest that intravenous cidofovir may have similar efficacy to intravenous ganciclovir or foscarnet in delaying progression of CMV retinitis. However, such comparisons must be made with caution because of potential differences in patient populations, data analysis techniques and interobserver variability in the masked assessment of retinal photographs. Nevertheless, intravenous cidofovir offers a less intrusive administration regimen than intravenous ganciclovir or foscarnet because of its prolonged dosage interval. Since therapy is life-long, patients receiving daily intravenous ganciclovir or foscarnet (but not cidofovir) usually require an indwelling central venous catheter and are therefore at increased risk of serious infection. The relatively long dosage interval for cidofovir may also have favourable implications in terms of overall treatment costs and patient quality of life, although specific data are very limited. Potentially irreversible nephrotoxicity is the major treatment-limiting adverse event associated with intravenous cidofovir in patients with AIDS-related CMV retinitis. Anterior uveitis/iritis has been reported frequently with intravenous cidofovir in postmarketing reports and a small number of patients have developed hypotony. Other treatment options for CMV retinitis are also associated with serious adverse events, and selection of pharmacotherapy will depend on a number of factors including retinitis lesion characteristics, patient quality-of-life issues and efficacy and tolerability profiles of available therapies.

CONCLUSION

Although the extent of its use may be limited by its adverse event profile, cidofovir offers a useful addition to the limited number of drugs available for the treatment of CMV retinitis in patients with AIDS.

Indolocarbazoles: potent, selective inhibitors of human cytomegalovirus replication

In our search for new, safer anti-HCMV agents, we discovered that the natural product Arcyriaflavin A (la) was a potent inhibitor of HCMV replication in cell culture. A series of analogues (symmetrical indolocarbazoles) was synthesised to investigate structure activity relationships in this series against a range of herpes viruses (HCMV, VZV, HSV1, and 2). This identified a number of novel, selective and potent inhibitors of HCMV, 12,13-dihydro-2,10-difluoro-5H-indolo[2,3-a]pyrrolo[3,4-c]carbazol e-5,7-(6H)-dione (1d) being the best example (IC50=40 nM, therapeutic index > 1450). Compounds described in this series were generally poor inhibitors of protein kinase C betaII, and no correlation was found between the ability to inhibit HCMV and the enzyme PKC.

Fluorophotometry in patients with human immunodeficiency virus with and without cytomegalovirus retinitis

OBJECTIVE

To study the aqueous humor dynamics in subjects with human immunodeficiency virus (HIV) with and without cytomegalovirus (CMV) retinitis.

DESIGN

Prospective cross-sectional study.

PARTICIPANTS

Fourteen HIV-positive subjects (27 eyes, 19 with CMV retinitis and 8 without CMV retinitis), and a control group of 9 HIV-negative subjects (17 eyes).

TESTING

Fluorophotometry.

MAIN OUTCOME MEASURES

Aqueous flow rates as measured by fluorophotometry and intraocular pressure (IOP).

RESULTS

Analysis of variance of the mean corrected aqueous flow rate revealed that both HIV-positive groups had significantly lower aqueous flow rates than did the control group (P < 0.03). No difference in mean aqueous flow rates was found between the HIV-positive eyes with or without CMV retinitis. Comparison of mean IOP revealed that HIV-positive eyes with CMV retinitis had significantly lower IOP than did the HIV-positive eyes without CMV retinitis (P = 0.03) and HIV-negative subjects (P = 0.002). There was no correlation between aqueous flow rate and IOP in HIV-positive subjects (P > 0.5).

CONCLUSION

The lack of correlation between the aqueous flow rate and IOP suggests that there may be some disassociation between these parameters in HIV-positive patients. Further studies are needed to better understand the mechanism of aqueous formation and in the management of disorders affecting IOP in this population.

Cidofovir in the treatment of cytomegaloviral disease

OBJECTIVE

To review the clinical pharmacology and microbiology of cidofovir in the therapy of cytomegalovirus (CMV) disease.

DATA SOURCES

Pertinent literature was identified via a MEDLINE search (October 1986-February 1997), and data from abstracts presented at recent scientific meetings were also included; unpublished information was provided by the manufacturer.

STUDY SELECTION

Antiviral activity data were included if widely accepted methodology was used. All clinical data currently available from human studies were also included.

DATA SYNTHESIS

Cidofovir is similar to ganciclovir in mechanism of action; however, cidofovir does not require viral enzymes for activation. Although the half-life of cidofovir in plasma is only 2.6 hours, the intracellular half-life may be much longer, allowing efficacy with biweekly maintenance dosing. In vitro, cidofovir appears to be equally or more effective than the other agents currently available for the treatment of CMV. In vivo, cidofovir appears to be effective in delaying the progression of CMV retinitis, although no clinical trials to date have directly compared cidofovir with either ganciclovir or foscarnet. Current intravenous dose recommendations are 5 mg/kg once weekly for two doses (induction), and then 5 mg/kg once every other week (maintenance). Since cidofovir is cleared almost entirely by the kidneys, dosage adjustments must be made in patients with impaired renal function. Disadvantages of cidofovir primarily include its risks of adverse drug reactions, such as nephrotoxicity, which is likely to occur in up to 50% of patients if appropriate preventative measures are not taken. Neutropenia and constitutional reactions to probenecid are also commonly encountered during the course of cidofovir therapy.

CONCLUSIONS

Cidofovir is the first acyclic phosphonate nucleoside antiviral agent to be approved for general use in the US. In addition to delaying the progression of CMV retinitis, cidofovir may provide some protective benefits to patients at risk for developing the disease and may be active against certain strains of virus resistant to other currently available therapies. Another advantage of cidofovir is its infrequent dosage schedule, which may prove beneficial in patients who are not compliant with daily intravenous dosing regimens. When determining the appropriate treatment for a patient with CMV retinitis, the benefits of using cidofovir must be weighed carefully against the risk of potentially serious adverse effects.

Virus infections of the eye

In reviewing the clinical features, diagnostic evaluations and therapies of the most common ocular viral infections we attempt to whet your appetite for attacking the numerous challenges in diagnosis and treatment of viral eye disease. The herpes viruses, HSV, VZV and CMV are the cause of significant ocular morbidity. HSV most commonly affects the cornea producing keratitis that can be recurrent and may lead to corneal clouding and neovascularisation. Manifestations can be purely infectious or immunological and treatment options must be tailored to the underlying pathophysiology. Herpes zoster ophthalmicus, caused by VZV infection of the first branch of the trigeminal nerve, produces a characteristic rash and can progress to keratitis and uveitis. HSV and VZV can cause retinitis in both immunocompetent and immunocompromised individuals. There has been a significant increase in the incidence of CMV retinitis since the beginning of the AIDS epidemic. We review the numerous new treatments, diagnostic tests and treatment strategies which have been developed in response to this potentially blinding retinal infection. Adenovirus produces an epidemic conjunctivitis and epidemic keratoconjunctivitis which are severe and extremely contagious conjunctival infections. HIV, molluscum contagiosum, EBV and rubeola also cause ocular diseases which are described.Copyright 1998 John Wiley & Sons, Ltd.

Anterior uveitis and hypotony after intravenous cidofovir for the treatment of cytomegalovirus retinitis

OBJECTIVE

This study aimed to describe the incidence and risk factors for the development of anterior uveitis in patients receiving intravenous cidofovir for the treatment of longstanding cytomegalovirus retinitis.

DESIGN

The study design was a retrospective cohort.

PARTICIPANTS

Eighteen patients (30 eyes) receiving parenteral cidofovir for the treatment of complicated cytomegalovirus retinitis participated.

MAIN OUTCOME MEASURES

The clinical response to parenteral cidofovir; the occurrence of anterior uveitis, and the management and outcome of patients with this complication; and the effect of cidofovir on intraocular pressure measurements were measured.

RESULTS

There was no progression or relapse of retinitis in patients receiving intravenous cidofovir. Eight (44%) of the 18 patients developed anterior uveitis, which occurred after a median of 4 doses of intravenous cidofovir. The median CD4+ cell count at the time of development of iritis was 101/mm3. Patients who developed uveitis had a mean increase in serum creatinine over baseline measurements (P = 0.05). The use of human immunodeficiency virus type-1 (HIV-1) protease inhibitors was not different between both groups of patients (P = 1.0). The development of anterior uveitis and visually significant hypotony necessitated withdrawal of cidofovir in only one patient.

CONCLUSIONS

Anterior uveitis was a common complication after intravenous cidofovir therapy. Despite the frequency of this complication, continued treatment with intravenous cidofovir was possible in the majority of patients. Patients with anterior uveitis after intravenous cidofovir may be treated successfully with topical corticosteroid therapy and cycloplegic agents.

Local therapy for cytomegalovirus retinitis

OBJECTIVE

To examine the role of intraocular therapy in the management of cytomegalovirus (CMV) retinitis associated with AIDS.

DATA SOURCES

A MEDLINE search was conducted for the years 1980-1997. In addition, relevant articles were cross-referenced to screen for additional information. The AIDS/HIV Treatment Directory was searched for information on ongoing studies.

STUDY SELECTION/DATA EXTRACTION

Data regarding the use of local antiviral therapy for CMV retinitis are cited. Emphasis was placed on randomized, controlled trials, but descriptive studies are also included.

DATA SYNTHESIS

Intraocular drug administration is an alternative therapy for CMV retinitis that avoids some of the disadvantages associated with systemic treatment. Intravitreal ganciclovir 200-2000 micrograms once weekly has been studied in a number of nonrandomized studies. Although initially effective, intravitreal ganciclovir is associated with a significant relapse rate and development of contralateral CMV retinitis. Intraocular ganciclovir implants offer the advantage of less frequent interventions and constant drug concentrations in the vitreous. Time to progression is significantly longer in patients receiving implants versus intravenous therapy; however, there is a higher incidence of contralateral eye retinitis and extraocular CMV disease with the implants. Currently, the intraocular implant is being studied in combination with oral ganciclovir to decrease the incidence of systemic CMV disease. Foscarnet and cidofovir have also been administered intravitreally for CMV retinitis. Cidofovir may offer the advantage of a long intracellular half-life, which would allow infrequent dosing; however, further study is needed to determine a safe and effective intraocular dosage.

CONCLUSIONS

Systemic therapy continues as standard management for CMV retinitis. Local therapy has some advantages and disadvantages, but larger, randomized, controlled trials comparing systemic therapy with local therapy must be completed to define its exact role. Data from an ongoing trial of local plus oral therapy will better define this role.

Adverse events and autopsy findings after intravitreous cidofovir (HPMPC) therapy in patients with acquired immune deficiency syndrome (AIDS)

OBJECTIVE

The purpose of the study is to evaluate the adverse events and autopsy findings in a series of consecutive 20-microg intravitreous cidofovir injections at a single institution.

DESIGN

The study design was a nonrandomized, consecutive case series.

PARTICIPANTS

Seventy-six patients with acquired immune deficiency syndrome with cytomegalovirus retinitis were studied prospectively. Sixty-three patients had 1 month's follow-up or longer, and this comprised the study group. In addition, histopathologic findings from 18 eyes of 9 patients were studied at autopsy.

INTERVENTION

A total of 296 injections of 20 microg cidofovir were given in 115 eyes. Sixty-three patients who had 246 injections in 93 eyes had 1 month's follow-up or longer for the evaluation of adverse events.

MAIN OUTCOME MEASURES

Postinjection chronic hypotony associated with permanent visual loss, transient hypotony, iritis, and its long-term sequela (posterior synechia and cataract, retinal detachment, extraocular cytomegalovirus involvement) were the outcomes of interest in this study. Additionally, light and electron microscopic studies of human eyes were performed.

RESULTS

The most severe adverse event was postinjection chronic hypotony. This phenomenon was associated with permanent visual loss. This was observed in 1% of the injections and 3% of the eyes of the patients (95% confidence interval, 0%-6%). Transient hypotony associated with mild-to-moderate visual loss developed in 14%, but vision recovered to baseline levels in these eyes subsequently. Analysis showed that transient hypotony in the injected eye could predict postinjection chronic hypotony in the fellow eye (two-tailed Fisher's exact test, P = 0.02). The incidence of iritis was 32%; posterior synechia and cataract were the long-term sequela of the iritis and developed in 19% and 11% of the eyes, respectively. The incidence of retinal detachment was lower (6%). Histopathologic evaluation of the eyes showed mild-to-moderate atrophy of the nonpigmented epithelium of the ciliary body and no other evidence of intraocular toxicity.

CONCLUSIONS

The most serious adverse event was postinjection chronic hypotony, which occurred in 3% of eyes. Episodes of transient hypotony appear to indicate that the fellow eye was predisposed to chronic hypotony. Therefore, it may be prudent to give intravitreous injections at least 2 weeks apart in the fellow eye to evaluate the clinical response of the injected eye.

In search of a selective antiviral chemotherapy

This article describes several approaches to a selective therapy of virus infections: (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU [brivudin]) for the therapy of herpes simplex virus type 1 and varicella-zoster virus infections: (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine (HPMPC [cidofovir]) for the therapy of various DNA virus (i.e., herpesvirus, adenovirus, papillomavirus, polyomavirus, and poxvirus) infections; 9-(2-phosphonylmethoxyethyl)adenine (PMEA [adefovir]) for the therapy of retrovirus, hepadnavirus, and herpesvirus infections; (R)-9-(2-phosphonylmethoxypropyl)adenine (PMPA) for the therapy and prophylaxis of retrovirus and hepadnavirus infections; and nonnucleoside reverse transcriptase inhibitors (NNRTIs), such as tetrahydroimidazo[4,5,1-jk][1,4]-benzodiazepin-2(IH)-one and -thione (TIBO), 1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine (HEPT), alpha-anilinophenylacetamide (alpha-APA), and 2',5'bis-O-(tert-butyldimethylsilyl)-3'-spiro-5"-(4"-amino-1",2"-oxat hiole- 2",2"-dioxide)pyrimidine (TSAO) derivatives, and thiocarboxanilides for the treatment of human immunodeficiency virus type 1 (HIV-1) infections. For the clinical use of NNRTIs, some guidelines have been elaborated, such as starting treatment with combinations of different compounds at sufficiently high concentrations to effect a pronounced and sustained suppression of the virus. Despite the diversity of the compounds described here and the different viruses at which they are targeted, they have a number of characteristics in common. As they interact with specific viral proteins, the compounds achieve a selective inhibition of the replication of the virus, which, in turn, should be able to develop resistance to the compounds. However, as has been established for the NNRTIs, the problem of viral resistance may be overcome if the compounds are used from the start at sufficiently high doses, which could be reduced if different compounds are combined. For HIV infections, drug treatment regimens should be aimed at reducing the viral load to such an extent that the risk for progression to AIDS will be minimized, if not avoided entirely. This may result in a real "cure" of the disease but not necessarily of the virus infection, and in this sense, HIV disease may be reduced to a dormant infection, reminiscent of the latent herpesvirus infections. Should virus replication resume after a certain time, the armamentarium of effective anti-HIV and anti-herpesvirus compounds now available, if applied at the appropriate dosage regimens, should make the virus return to its dormant state before it has any chance to damage the host. It is unlikely that this strategy would eradicate the virus and thus "cure" the viral infection, but it definitely qualifies as a cure of the disease.

Clinical uses of cidofovir

Cidofovir is a cytidine nucleotide analogue recently licensed as an intravenous treatment for CMV retinitis in AIDS patients. Three controlled clinical trials have demonstrated efficacy of cidofovir for this indication, and have generated data useful as a guideline to prevent potential toxicity. Although de novo emergence of resistance to cidofovir has not been observed clinically in patients receiving cidofovir, cross-resistance to cidofovir in ganciclovir-resistant clinical DNA polymerase mutants has been identified. Cross-resistance of cidofovir and foscarnet has not been identified to date. A broad spectrum agent with in vitro activity against human herpesviruses, adenovirus, HPV, polyomaviruses and human poxviruses, cidofovir is under clinical investigation for a variety of potential applications. Examples include intravenous administration of cidofovir for treatment of progressive multifocal leukoencephalopathy and Kaposi's sarcoma, intraocular injection for treatment of CMV retinitis, intralesional injection for treatment of respiratory papillomatosis, topical application for treatment of molluscum contagiosum, anogenital condyloma acuminata, and recurrent genital herpes, and ophthalmic instillation for treatment of viral keratoconjunctivitis. Copyright 1997 John Wiley & Sons, Ltd.

Intraocular pressure and aqueous humor dynamics in patients with AIDS treated with intravitreal cidofovir (HPMPC) for cytomegalovirus retinitis

PURPOSE

To evaluate the decrease in intraocular pressure associated with cidofovir (1-[(S)-3-hydroxy-2-(phosphonomethoxy)propyl]cytosine dihydrate; HPMPC) intravitreal injections.

METHODS

We followed up 97 eyes of 63 patients with acquired immunodeficiency syndrome (AIDS) who had cytomegalovirus retinitis and had been treated with up to nine 20-microgram intravitreal cidofovir injections. Measurements were taken at baseline, between 2 and 3 weeks, and at 5 to 6 weeks after injections. Anterior chamber fluorophotometry was studied in seven eyes (four patients) before and after injections. Ciliary body anatomy was evaluated in two patients.

RESULTS

After the first intravitreal injection, mean intraocular pressure was 2.2 mm Hg lower than that at baseline at 2 to 3 weeks (P < .001) and 1.3 mm Hg lower than at baseline at 5 to 6 weeks (P = .0025). After the second injection, mean pressure was 2.6 mm Hg lower at 2 to 3 weeks (P = .0013) and 1.5 mm Hg lower at 5 to 6 weeks (P = .043). After subsequent injections, however, the decrease was less than 1 mm Hg, suggesting that a plateau had been reached. Pressure in eyes with anterior uveitis after the first injection was lower than that in eyes without anterior uveitis (P < .0001). The mean rate of aqueous flow decreased from 2.8 to 1.9 microliters per minute 2 to 4 weeks after injection (P < .015). Ultrasound biomicroscopy disclosed that severe hypotony after cidofovir injections is associated with ciliary body atrophy.

CONCLUSIONS

Intraocular pressure decreases after the initial 20-microgram cidofovir intravitreal injection. However, eyes stabilize (pressure plateaus) after three injections. Effects on the ciliary body are the main cause of the decrease after cidofovir injections.

Low-dose intravitreal cidofovir (HPMPC) therapy of cytomegalovirus retinitis in patients with acquired immune deficiency syndrome

PURPOSE

The authors have shown that long-term treatment of cytomegalovirus (CMV) retinitis with 20-microgram intravitreal injections of cidofovir (HPMPC) is highly effective but may be associated with iritis and profound hypotony. They evaluated the efficacy and safety of 10-microgram intravitreal injections of cidofovir and made comparisons with their findings of 20-microgram injections.

METHODS

The current study was conducted as a nonrandomized consecutive case series at the AIDS Ocular Research Unit of the University of California at San Diego. Twenty-seven eyes of 18 patients were injected with 10 micrograms intravitreal cidofovir and had complete follow-up. These were compared with another consecutive series of 24 eyes of 17 patients injected with 20 micrograms of cidofovir.

MAIN OUTCOME MEASURES

The main outcome in this study was the incidence of failure to respond to treatment with 10-microgram injections. The authors also compared the time to progression of CMV retinitis after the initial intravitreal injections of 10 micrograms and 20 micrograms of cidofovir. Secondary outcomes included incidence of iritis and changes in intraocular pressure (IOP) after cidofovir injections.

RESULTS

The median time to retinitis progression was 45 days after a single intravitreal injection of 10 micrograms cidofovir compared with 55 days with the authors' series of 20-microgram injections. This difference was statistically significant (P = 0.033, log-rank test) and appeared to be due principally to a 26% incidence of primary failure in the 10-microgram group (progression > or = 750 microns within 28 days, P = 0.0017 Wilcoxon test). Progression after a second injection of 10 micrograms cidofovir was more rapid (32 days, P = 0.037). The incidence of iritis after 10-microgram injections was 2.2% compared with 23% with 20-microgram injections (P = 0.003, Fisher's exact test, two-tailed). There was less decrease in IOP between the baseline injection and subsequent visits in the 10-microgram group.

CONCLUSIONS

Treatment of CMV retinitis with 10-microgram intravitreal cidofovir injection was not as effective as with 20 micrograms and may allow development of drug resistance, but there were fewer side effects with the 10-microgram dose. The drug appears to have a narrow therapeutic index, and other attempts at reducing the side effects while preserving the long-acting effect, such as liposome delivery, may be warranted.

(S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine (HPMPC) inhibits HIV-1 replication in epithelial cells, but not T-lymphocytes

PMEA [9-(2-phosphonylmethoxyethyl)adenine] inhibited both HSV-1 and HIV-1 replication in MT-2 and HeLa-CD4 cells. (S)-1-[3-hydroxy-2-(phosphonylmethoxy)propyl]cytosine (HPMPC) inhibited both these viruses in the epithelioid HeLa-CD4 cells, but did not inhibit either virus in the T-lymphocytic MT-2 cells. PMEA and HPMPC are metabolized to their diphosphorylated forms within cells, which then inhibit viral polymerases. We therefore compared the metabolism of PMEA and HPMPC in MT-2 and HeLa CD4 cells. PMEApp formation was efficient in both the cell types, whereas HPMPCpp levels were approximately 3-10 fold lower in MT-2 cells, compared to HeLa-CD4 cells. These results indicate that HPMPC can inhibt HIV replication in the appropriate cell types, and show that differences in their metabolism cannot account entirely for the lack of antiviral efficacy of HPMPC in MT-2 cells.

Anterior nongranulomatous uveitis after intravitreal HPMPC (cidofovir) for the treatment of cytomegalovirus retinitis. Analysis and prevention

BACKGROUND AND OBJECTIVE

The authors characterize and analyze the incidence of a previously reported mild anterior nongranulomatous uveitis associated with intravitreal injections of (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine (HPMPC), also termed cidofovir (Vistide, Gilead Sciences, Foster City, CA). This is an acyclic nucleoside phosphonate analogue with a potent anticytomegalovirus effect. The authors also analyzed the effects of probenecid therapy, as well as prophylaxis with probenecid plus topical corticosteroids and cycloplegics on the course and outcome of the uveitis.

METHODS

Prospective case series from a tertiary referral center, which included 46 consecutive patients with acquired immune deficiency syndrome (AIDS) and cytomegalovirus (CMV) retinitis. There was a total of 130 injections in 69 eyes treated with 20 micrograms of intravitreal HPMPC. Forty-one patients (119 injections) received oral probenecid, 5 patients (11 injections) did not, and 21 patients (53 injections) received topical corticosteroids and cycloplegics as an adjuvant to probenecid in the prophylaxis of iritis.

RESULTS

Mild to moderate nongranulomatous iritis was seen in 26% of patients after their first injection (n = 12). Patients receiving probenecid prophylaxis after first injection had a significantly lower frequency of iritis versus patients who did not receive probenecid at the time of first injection (P = 0.0089). In contrast, treatment with topical corticosteroid and cycloplegics after injection did not statistically significantly affect the frequency of iritis in patients (P = 0.44). The development of iritis after a second injection of HPMPC was more likely if it had occurred after the initial injection (P = 0.015; Fisher's exact test). All cases of iritis were treated with topical corticosteroids and cycloplegics, and there was no permanent impairment of vision secondary to iritis after HPMPC injection in any eyes.

CONCLUSIONS

Anterior uveitis was seen in 26% of patients after first-time HPMPC injection. Concomitant use of probenecid appears to decrease the frequency of the iritis from 71% to 18% in patients with AIDS and CMV retinitis after the first intravitreal injection of HPMPC. Topical corticosteroid administration after injection (before iritis) was ineffective in preventing iritis treatment with topical corticosteroids and cycloplegics resulted in resolution of all iritis cases.

Design, synthesis, and antiviral evaluation of 2-substituted 4,5-dichloro- and 4,6-dichloro-1-beta-D-ribofuranosylbenzimidazoles as potential agents for human cytomegalovirus infections

The syntheses of 2,4,6-trichlorobenzimidazole (4a) and 2-bromo-4,6-dichlorobenzimidazole (4b) were accomplished via the 2-amino intermediate (3) using a mild diazotization procedure. Ribosylation of 4a and 4b and subsequent deprotection afforded the corresponding 2,4,6-trichloro-1-beta-D-ribofuranosylbenzimidazole (7a) and 2-bromo-4,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (7b). The 2-azido (10), 2-amino (11), 2-thione (13), 2-methylthio (14a), and 2-benzylthio (14b) derivatives were prepared via displacement reactions at the 2-position of the 2,3,5-tri-O-acetyl derivative of 7a. 2,4,5-Trichlorobenzimidazole (17a) and 2-bromo-4,5-dichlorobenzimidazole (17b) were synthesized from the corresponding 1,2-phenylenediamines via successive cyclization with cyanogen bromide and diazotization in the presence of an appropriate cupric halide. Ribosylation of compounds 17a and 17b was followed by deprotection to afford 2,4,5-trichloro-1-beta-D-ribofuranosylbenzimidazole (20a), and 2-bromo-4,5-dichloro-1-beta-D-ribofuranosylbenzimidazole (20b). Heterocycles (3, 4a, 17a) and nucleosides (7a, b, 8, 10, 11, 13, 14a,b, 20a,b) were evaluated for activity against human cytomegalovirus (HCMV) and herpes simplex virus type 1 (HSV-1) and for cytotoxicity. The 2-chloro but not the 2-amino heterocycles were active against HCMV (IC50's = 5-8 microM) but not HSV-1; both also were somewhat cytotoxic to uninfected cells (IC50's = 32-100 microM). Among the nucleosides, the 2-chloro and 2-bromo analogs in both the 4,5- and 4,6-dichloro series (20a,b, 7a,b, respectively) were active against HCMV (IC50's = 1-10 microM) and noncytotoxic in their antiviral dose ranges. The 2-bromo compounds were more active than the 2-chloro analogs; the 2-azido and 2-thiobenzyl analogs (10, 14b) were weakly active against HCMV, but this activity was not well separated from cytotoxicity. None of the nucleosides were active against HSV-1. This pattern of activity and cytotoxicity is similar to that of the 2-chloro- and 2-bromo-5,6-dichloro analogs (TCRB, BDCRB) which we reported previously. Although these new 4,5- and 4,6-dichloro analogs are potent and selective inhibitors of HCMV, they are not as potent at TCRB and BDCRB.

Design, synthesis, and antiviral evaluation of 2-chloro-5,6-dihalo-1-beta-D-ribofuranosylbenzimidazoles as potential agents for human cytomegalovirus infections

2-Chloro-5,6-difluorobenzimidazole (8) was prepared from 4,5-difluoro-2-nitroaniline (5) via successive reduction, cyclization, and diazotization reactions. 2-Chloro-5,6-dibromobenzimidazole (10) was obtained by a direct bromination of 2-chlorobenzimidazole (9) with bromine-water. 2-Chloro-5,6-diiodobenzimidazole (15) was synthesized by a stepwise transformation of the nitro functions of 2-chloro-5,6-dinitrobenzimidazole (11) into iodo groups via diazotization reactions. Ribosylation of 8, 10, and 15 gave the respective beta nucleosides 16a-c as the major products along with a small amount of the alpha anomers 17a-c. Deprotection of 16a-c afforded the corresponding free beta nucleosides 2-chloro-5,6-difluoro-1-beta-D-ribofuranosylbenzimidazole (2), 2-chloro-5,6-dibromo-1-beta-D-ribofuranosylbenzimidazole (3), and 2-chloro-5,6-diiodo-1-beta-D-ribofuranosylbenzimidazole (4). Similar deprotection of the alpha anomers (17a-c) resulted in a removal of the acetyl protecting groups and a concomitant cyclization to give the 2,2'-O-cyclonucleosides (18a-c). Most of the benzimidazole heterocycles, but not the difluoro analog, were active against human cytomegalovirus (HCMV) (IC50's = 3-40 microM) and herpes simplex virus type 1 (HSV-1) (IC50's = 50-90 microM). This activity, however, was not well separated from cytotoxicity, IC50's = 10-100 microM. The corresponding unsubstituted, the 5,6-dimethyl, and the 5,6-difluoro ribonucleosides (19, 20, and 2, respectively), were inactive against both viruses. Similar to the previously reported 2,5,6-trichloro analog (TCRB), the 5,6-dibromo ribonucleoside 3 was active against HCMV (IC50 approximately 4 microM) but more cytotoxic than TCRB. The 5,6-diiodo analog 4 also was active (IC50 approximately 2 microM) but more cytotoxic (IC50 = 10-20 microM) than either 3 or TCRB. The cyclonucleosides were inactive against both viruses and not cytotoxic, or slightly active with corresponding cytotoxicity. The order of activity against HCMV of the dihalobenzimidazole ribonucleosides was I approximately equal to Br approximately equal to CI > > F > H = CH3. The order of cytotoxicity among the most active compounds, however, was I > Br > Cl, thereby establishing that TCRB had the best antiviral properties.

Therapeutic options for resistant cytomegalovirus retinitis

Untreated cytomegalovirus (CMV) retinitis is progressive and generally leads to blindness within 6 months. Intravenous (i.v.) therapies such as foscarnet and ganciclovir, which were the first agents approved for the treatment of CMV retinitis, are effective in suppressing CMV replication, but they delay rather than prevent reactivation of CMV infection resulting in relapse of the disease. Furthermore, studies have shown that the time between subsequent reactivations becomes shorter, with each relapse producing more serious disease that may be more difficult to manage. This clinical failure may be caused in part by drug resistance; approximately 10% of all patients receiving systemic treatment with these agents may harbor drug-resistant viral strains. With three systemic therapies (ganciclovir, foscarnet, and cidofovir) now available for the treatment of CMV retinitis, several options exist for patients who have failed therapy with one of these drugs: reinduction with the same i.v. agent, switching therapies, or combining therapies. Resistant or relapsing CMV retinitis may also be treated by local therapies such as intraocular injections of ganciclovir and foscarnet or with a sustained-release ganciclovir implant. However, local therapy is ineffective in controlling extraocular or fellow eye CMV disease. It is likely that the integration of both local and systemic therapies will be required to halt the relentless progression of this debilitating disease, particularly when clinical resistance is encountered.

Cytomegalovirus antigenemia in acquired immunodeficiency syndrome patients with untreated cytomegalovirus retinitis

PURPOSE

To determine the frequency of cytomegalovirus (CMV) viremia in patients with acquired immunodeficiency syndrome (AIDS) and untreated CMV retinitis using conventional cell culture isolation and the sensitive CMV antigenemia assay.

METHODS

We examined 24 AIDS patients with ophthalmologic diagnosis of untreated CMV retinitis and 24 AIDS patients without present or past retinitis (control patients) from three medical centers between September 1992 and March 1994. Cytomegalovirus antigenemia was detected by an indirect peroxidase staining in 300,000 cytocentrifuged neutrophils, using a mixture of murine monoclonal antibodies directed against the pp65 lower matrix protein of CMV.

RESULTS

Positive antigenemia was demonstrated in eight (33.3%) of the 24 retinitis patients and in none of the 24 control patients (P < .001). Only two of the eight antigenemia-positive patients had a concurrent positive CMV isolation from blood leukocytes by conventional cell culture assay.

CONCLUSIONS

These results emphasize the risk of extraocular disease in AIDS patients with CMV retinitis because the virus is often present in peripheral blood leukocytes. The CMV antigenemia assay may be a simple and rapid means of identifying those patients with unilateral retinitis at highest risk of developing CMV retinitis of the fellow eye or of visceral CMV disease if intravitreal injections or implants are used as sole treatment for CMV retinitis.

Ophthalmic complications of HIV infection

HIV retinopathy, a noninfectious microangiopathy, is the most common ocular manifestation of HIV infection. Opportunistic infections, neoplasms, neuro-ophthalmic lesions, and drug-induced lesions may also cause ocular problems. Opportunistic ocular infections, particularly CMV retinitis, are a major cause of morbidity in patients with AIDS. Because of the underlying chronic and progressive immune dysfunction, the ocular symptoms, signs, clinical course, and treatment are often atypical and severe, requiring protracted medical therapy.

Correlation between intraocular pressure and CD4+ T-lymphocyte counts in patients with human immunodeficiency virus with and without cytomegalovirus retinitis

PURPOSE

To determine the intraocular pressure in patients with human immunodeficiency virus (HIV) with and without cytomegalovirus retinitis, and to correlate intraocular pressure with CD4+ T-lymphocyte count and the presence, extent, and activity of cytomegalovirus retinitis.

METHODS

Intraocular pressure was measured with calibrated Goldmann applanation tonometers in two groups of patients. Group A included 84 patients with HIV (120 eyes) with cytomegalovirus retinitis, and Group B included 110 patients with HIV (183 eyes) without cytomegalovirus retinitis. Thirty-three patients without HIV (66 eyes) were included as a control group. Step-wise regression analysis of intraocular pressure included correlation with cytomegalovirus retinitis (presence, extent, and activity), CD4+ T-lymphocyte count, age, and gender.

RESULTS

The mean intraocular pressure was 9.8 mm Hg in Group A, 12.6 mm Hg in Group B, and 16.1 mm Hg in the control group. All three groups were statistically different from each other when intraocular pressure was compared (P < .0001). Step-wise regression showed that low CD4+ T-lymphocyte count (r2 = .20; P < .0001) and extent of cytomegalovirus retinitis (r2 = .08; P = .007) both correlated to low intraocular pressure.

CONCLUSION

Intraocular pressure is lower than normal in patients with HIV. Decreased CD4+ T-lymphocyte count is the major association with low intraocular pressure (20% of the effect); extent of cytomegalovirus retinitis accounts for 8% of the effect. Knowledge of the normal range of intraocular pressure in patients with HIV will be important to the understanding and treatment of glaucoma and other disorders or treatments affecting intraocular pressure.