A randomized, controlled trial of foscarnet in the treatment of cytomegalovirus retinitis in patients with AIDS

Ganciclovir. An update of its therapeutic use in cytomegalovirus infection

The antiviral nucleoside analogue ganciclovir has demonstrated in vitro activity against human cytomegalovirus and effectively treats infection caused by this organism in various immunocompromised patient groups. The drug prolongs time to progression in patients with acquired immune deficiency syndrome (AIDS)-related cytomegalovirus retinitis although life-long maintenance therapy is required. Direct comparisons between ganciclovir and foscarnet in this indication are few; nevertheless, the 2 drugs appear to have equal therapeutic efficacy in treating cytomegalovirus retinitis although results from 1 study in this indication suggest that foscarnet has an advantage in terms of patient survival. AIDS-related gastrointestinal and, to a lesser extent, pulmonary cytomegalovirus infection also respond to treatment with ganciclovir; maintenance therapy does not appear to be required in these latter 2 indications. Ganciclovir is also useful against cytomegalovirus infection in organ transplant recipients. The drug is most effective when given prophylactically or as early treatment for asymptomatic infection in bone marrow transplant recipients; treatment of established infection is less effective in this patient group. However, established infection in solid organ transplant recipients appears to respond to treatment with ganciclovir. The most common adverse event during ganciclovir therapy is haematological toxicity but this appears to be readily reversible on discontinuation of the drug. In addition, coadministration of granulocyte colony-stimulating factor (G-CSF) or granulocyte-macrophage CSF (GM-CSF) has been shown to prevent ganciclovir-associated neutropenia. Thus, ganciclovir is a valuable treatment for cytomegalovirus infection in patients with AIDS and in organ transplant recipients. Further studies comparing ganciclovir and foscarnet-ideally incorporating the use of G-CSF or GM-CSF to prevent ganciclovir-associated neutropenia and assessing survival as 1 endpoint--should further clarify the relative role of ganciclovir as treatment or prophylaxis for cytomegalovirus infection.

Foscarnet. A reappraisal of its antiviral activity, pharmacokinetic properties and therapeutic use in immunocompromised patients with viral infections

The DNA polymerase of human herpes viruses, including cytomegalovirus (CMV), and the reverse transcriptase of human immunodeficiency virus (HIV) are selectively inhibited in vitro by the pyrophosphate analogue foscarnet. Inhibition is reversible on withdrawal of foscarnet and additive or synergistic effects have been demonstrated in vitro with other antiviral drugs, including ganciclovir and zidovudine. Foscarnet appears to have negligible effects on host enzymes and cells. Complete or partial clinical resolution of ocular symptoms is obtained in more than 89% of patients with acquired immunodeficiency syndrome (AIDS) and CMV retinitis during foscarnet induction therapy, but relapse occurs soon after ceasing treatment. Maintenance treatment given daily can extend the period of remission considerably. Foscarnet and ganciclovir monotherapy had similar efficacy in the treatment of CMV retinitis in patients with AIDS in several studies, and have been used concomitantly in immunocompromised patients with recalcitrant CMV infections. In 1 trial, patients receiving foscarnet survived for significantly longer than those receiving ganciclovir. Foscarnet has been used successfully in the treatment of limited numbers of immunocompromised patients with CMV-associated gastrointestinal (improvement in over 67% of patients) and other infections. Aciclovir-resistant herpes simplex infections in immunocompromised patients have also been treated successfully with foscarnet. Almost 90% of a foscarnet dose is excreted in the urine. Reversible nephrotoxicity is common during foscarnet therapy, but may be reduced by dosage adjustment and adequate hydration. Anaemia, nausea and vomiting, disturbances in electrolyte levels and genital ulceration have also been associated with administration of the drug. The different tolerability profiles of foscarnet and zidovudine facilitate the use of these agents in combination in patients with AIDS and CMV infection; whereas ganciclovir, like zidovudine, is associated with dose-limiting haematological toxicity. The apparent survival benefits seen in these patients when receiving foscarnet and zidovudine (possibly linked to synergy between zidovudine and foscarnet and/or the inherent anti-HIV activity of foscarnet), appear to offer potentially important advantages for foscarnet over ganciclovir in the treatment of selected patients with AIDS and CMV infections.

Concurrent use of foscarnet and ciprofloxacin may increase the propensity for seizures

OBJECTIVE

To report a possible interaction between foscarnet and ciprofloxacin in two patients with AIDS, cytomegalovirus (CMV) retinitis, and disseminated Mycobacterium avium complex (MAC) infection and to review the available literature related to foscarnet-associated seizures.

DATA SOURCE

Case report information was obtained from Medical Service Daily Rounds during the patients' hospitalization and from the patients' medical records. Computerized (MEDLINE) and manual (Index Medicus) search methods were used to obtain English-language literature published between 1980 and 1993.

DATA SYNTHESIS

Foscarnet is a synthetic antiviral agent with activity against herpesviruses and HIV. The incidence of seizures with foscarnet infusion is high, ranging from 13 to 15 percent. Predisposing factors such as renal impairment, electrolyte and metabolic abnormalities, and underlying neurologic disorders have been associated with seizures during foscarnet therapy. We describe two patients with AIDS who developed generalized tonic-clonic seizures while receiving foscarnet and ciprofloxacin for the treatment of CMV retinitis and disseminated MAC infection, respectively. Neither of the patients had any of the aforementioned risk factors for foscarnet-associated seizures.

CONCLUSIONS

Concurrent administration of ciprofloxacin, a known epileptogenic agent, and foscarnet may predispose patients to the development of seizures.

Combined daily therapy with intravenous ganciclovir and foscarnet for patients with recurrent cytomegalovirus retinitis

We treated seven patients (nine eyes) who had cytomegalovirus retinitis with daily intravenous ganciclovir plus foscarnet. All patients had demonstrated multiple progressions of retinitis on single-drug therapy, and some were intolerant to induction doses of one or both medications. Before combination therapy, the median number of progressions was five per patient. The mean interval between progressions was 11 weeks, and the mean interval before the final progression was four weeks. While taking combination therapy, two patients showed progression after 14 and 34 weeks. Two patients showed no progression after 17 and 36 weeks of follow-up. Three patients died after five, 14, and 23 weeks, respectively, without progression of retinitis. In every patient, the progression-free interval was longer during combination therapy than the previous progression-free interval during single-drug therapy. In no case was combination therapy stopped because of toxicity. Combination therapy was fairly well tolerated and appeared to prolong the interval to progression and to preserve vision in our patients.

The development of cytomegalovirus encephalitis in AIDS patients receiving ganciclovir

PURPOSE

Cytomegalovirus (CMV) retinitis in patients with the acquired immunodeficiency syndrome (AIDS) requires lifelong therapy with either intravenous ganciclovir sodium or foscarnet sodium. From June 1989 through February 1992, seven patients with AIDS were diagnosed to have CMV retinitis, and all were treated with ganciclovir. Five of the seven developed abrupt preterminal mental status changes. All five with mental status changes received anti-CMV therapy until the time of death. Autopsies were performed in all cases to determine the cause of mental status changes.

PATIENTS AND METHODS

Five patients with AIDS and newly diagnosed CMV retinitis. Retrospective case analyses with autopsies. All five patients were treated with gangciclovir immediately upon the diagnosis of CMV retinitis and received ganciclovir at standard dosages until death.

RESULTS

Four patients had clinically stable retinitis throughout the entire course of ganciclovir therapy. In the fifth patient, because of fundoscopic deterioration, foscarnet therapy was initiated 1 month prior to death. Cerebrospinal fluid analysis and magnetic resonance imaging, although abnormal, were not diagnostically specific. Neuropathologic examination revealed fulminant diffuse CMV encephalitis in all patients, with prominent ependymal and periventricular necrosis.

CONCLUSIONS

These results suggest that while ganciclovir therapy may clinically stabilize CMV retinitis in patients with AIDS, it does not appear to prevent the development of, or be effective in the treatment of, CMV encephalitis. Thus, clinicians should consider the diagnosis of CMV encephalitis in patients receiving ganciclovir who develop mental status changes and, if possible, alter therapy accordingly.

Pharmacodynamic relationship of pharmacokinetic parameters of maintenance doses of foscarnet and clinical outcome of cytomegalovirus retinitis

The pharmacodynamic relationship between a range of foscarnet exposure measurements obtained from studying nine patients receiving ongoing maintenance therapy for cytomegalovirus retinitis and a range of efficacy values (days to retinitis progression) obtained by independent examination of serial retinal photographs from the same nine patients was analyzed. In the resulting proportional hazards models, the foscarnet area under the concentration-time curve approached statistical significance (P = 0.11) as a predictor of decreased risk of retinitis progression.

Foscarnet for suppression of human immunodeficiency virus replication

The effect of foscarnet against human immunodeficiency virus (HIV) was evaluated in nine HIV-infected individuals; six completed 28 days of induction therapy. The overall mean increase in CD4+ lymphocytes was 64 cells per mm3. The mean decline in the HIV antigen concentration was 108 pg/ml (P = 0.03), and suppression was related to systemic foscarnet exposure by a maximum-effect pharmacodynamic model.

Safety of alternating ganciclovir and foscarnet maintenance therapy in human immunodeficiency virus (HIV)-related cytomegalovirus infections. An open-labeled pilot study

In the treatment of cytomegalovirus (CMV) disease in patients with AIDS, a life-long suppression therapy following an induction therapy consisting of ganciclovir or foscarnet is essential. Due to drug-related toxicities, anti-CMV therapy frequently has to be discontinued. To determine whether toxicities and side effects may be reduced with an alternating combination therapy consisting of ganciclovir and foscarnet (ganciclovir: 5 mg/kg every other day; foscarnet: 120 mg/kg every other day), 10 AIDS patients with CMV disease received this maintenance therapy for a median time of 18.5 weeks (5-51 weeks). Side effects were reported from 5 patients (nausea 5, malaise/fatigue 2, penile ulcers 1). Hematological or renal toxicities were mild, 1-week discontinuation of therapy due to neutropenia was necessary in 1 patient. Progression of CMV disease was observed in 3 patients at 2, 6, and 30 weeks of maintenance therapy. Median relapse-free interval for all patients was 105 days. We conclude that combination therapy with ganciclovir and foscarnet can be used safely for induction and maintenance therapy. Therefore, this regimen should be assessed in further trials to evaluate safety, efficacy, and the development of resistance in comparison to ganciclovir or foscarnet monotherapy.

Effect of foscarnet induction treatment on quantitation of human cytomegalovirus (HCMV) DNA in peripheral blood polymorphonuclear leukocytes and aqueous humor of AIDS patients with HCMV retinitis. The Italian Foscarnet Study Group

The aim of this study was to investigate peripheral blood polymorphonuclear leukocytes and, whenever possible, aqueous humor from 65 AIDS patients with ophthalmoscopically diagnosed human cytomegalovirus (HCMV) retinitis to determine (i) whether patients consistently carry viral DNA and (ii) to what extent foscarnet induction treatment decreases viral DNA levels. HCMV DNA was quantified by PCR using densitometric analysis of hybridization products obtained from external standards and a standard curve from which the number of genome equivalents of test samples, normalized by using an internal amplification control, was interpolated. Results showed that 56 of 65 patients (86.1%) were positive for HCMV DNA prior to induction treatment. Of 41 of the 56 patients (73.2%) whose blood had become DNA negative after induction, only 5 had a high viral load (> 5,000 genome equivalents per 2 x 10(5) polymorphonuclear leukocytes) prior to induction, whereas as many as 13 of the 15 (26.8%) patients remaining DNA positive after induction had a high viral load prior to induction. Finally, of the nine patients (13.8%) with DNA-negative blood prior to induction treatment, three were shifted to foscarnet from ganciclovir, while six were erroneously enrolled in the study. Pre- and postinduction aqueous humor samples were obtained from 12 patients; all of these were DNA positive prior to induction, whereas after induction, 4 became negative, 6 showed a marked decrease in viral DNA, and 2 had nearly stable low DNA levels. In conclusion, PCR is a valuable tool for etiologic diagnosis and monitoring of HCMV retinitis treatment in AIDS patients. HCMV DNA is consistently present in the blood and aqueous humor of all patients with HCMV retinitis. Foscarnet induction treatment is highly effective in suppressing or reducing DNA levels in both blood leukocytes and aqueous humor.

"The end of innocence" revisited: resistance of herpesviruses to antiviral drugs

In the past 4 years, interest in drug-resistant herpesviruses has evolved from the realm of academic laboratory studies to that of great clinical importance. Recurrent and persistent infections due to the herpes simplex viruses, varicella-zoster virus, and human cytomegalovirus have been an unwelcome consequence of immunosuppression in graft recipients, cancer patients, and those suffering from AIDS. Treatment of these infections with the available antiviral drugs, such as acyclovir, ganciclovir, and foscarnet, has resulted in both clinical benefit and the emergence of drug-resistant variants. In addition, the role of Epstein-Barr virus is being clarified for an array of disease syndromes, and therapeutic approaches are beginning to emerge. In the present review, the emergence and clinical importance of drug resistance among the herpesviruses have been explored. Furthermore, particular attention has been focused on our understanding of the mechanisms of drug resistance and how that understanding will guide us in the development of more effective antiviral drugs and drug usage.

Cytomegalovirus retinitis: diagnosis and treatment

Cytomegalovirus (CMV) is a non-pathogenic organism in the immunocompetent, but is a major cause of morbidity and mortality amongst patients with AIDS, and the retina is the commonest site of infection. If left untreated, patients with CMVR will develop disease in their second eye and ultimately become blind. However, with correct diagnosis and treatment useful vision can be maintained in the majority of cases. Fifteen to 20% of patients with AIDS will contract cytomegalovirus retinitis (CMVR) and this may be the AIDS-defining diagnosis though more commonly it occurs months after the diagnosis of AIDS. Given the increasing number of HIV positive patients and their longer survival, it is likely that CMVR will become an increasingly prevalent condition. In these patients loss of sight from CMVR has devastating consequences in terms of loss of independence and quality of life and therefore ophthalmologists and physicians should be aware of the presenting characteristics of CMVR, be familiar with therapy and its complications, and be able to recognize relapsing infection.

Antiviral activity of a phosphorothioate oligonucleotide complementary to RNA of the human cytomegalovirus major immediate-early region

Phosphorothioate oligonucleotides complementary to mRNA of the human cytomegalovirus (HCMV) DNA polymerase gene or to RNA transcripts of the major immediate-early regions 1 and 2 (IE1 and IE2) of HCMV were evaluated for antiviral activity in a 96-well immunoassay with primary human dermal fibroblasts as host cells. Oligonucleotides complementary to RNA of the IE2 region exhibited the most potent antiviral activity. One of these oligonucleotides, ISIS 2922, was at least 30-fold more potent than the nucleoside analog, ganciclovir, with a 50% effective concentration of 0.37 microM in the 96-well immunoassay. In an infectious virus yield reduction assay, ISIS 2922 and ganciclovir reduced production of infectious virus by 2 log units at concentrations of 2.2 and 36 microM, respectively. A control oligonucleotide showed no inhibition of virus production at concentrations as high as 3 microM. ISIS 2922 reduced IE protein synthesis in HCMV-infected cells in a dose-dependent manner which correlated with antiviral activity. The antiviral activity of ISIS 2922 was not due to oligonucleotide-induced cytotoxicity since effects on cell viability or proliferation were observed only at concentrations well in excess of effective antiviral concentrations. The specificity and potency of ISIS 2922 suggest that it may be useful for the treatment of cytomegalovirus disease in humans.

A rare cause of visual loss in AIDS patients: central retinal vein occlusion

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Pathology of cytomegalovirus retinitis treated with sustained release intravitreal ganciclovir

BACKGROUND

An experimental sustained release intraocular device has been designed to deliver ganciclovir over a long period of time. As part of an efficacy trial, the ganciclovir intraocular device was used to treat cytomegalovirus (CMV) retinitis in patients with acquired immune deficiency syndrome (AIDS).

METHODS

All patients had active CMV retinitis that had progressed despite intravenous ganciclovir therapy. The ganciclovir intraocular device was inserted into the vitreous cavity by making an inferotemporal full-thickness circumferential sclerotomy and anchored to the incision. Intravenous therapy was then discontinued and patients were followed up at 2-week intervals until death. Seven eyes from five patients were obtained 2 to 10 hours postmortem and submitted for histopathologic examination. Light and electron microscopic studies were performed and correlated to the clinical outcome. Follow-up period after device placement ranged from 16 to 82 days (median, 70 days).

RESULTS

All seven eyes showed clinical stabilization of the CMV retinitis. Light microscopy showed varying degrees of retinal atrophy with areas of gliosis. In addition, we observed syncytial megalic cells containing Cowdrey type A inclusions affecting all layers of the retina. Concurrent choroidal infections with Pneumocystis carinii (1) and Mycobacterium avium (2) also were seen. Electron microscopy showed virus particles located mostly at the junction of uninvolved and "healed" retinitis. No evidence of retinal toxic effects or inflammation at the site of ganciclovir intraocular device implant was noted.

CONCLUSION

The ganciclovir intraocular device appeared to be effective in controlling the progression of CMV retinitis. The clinical and pathologic results are similar to those observed in the eyes of patients with intravenously administered ganciclovir. The lack of toxic effects and sustained levels of intravitreal ganciclovir may provide an improved therapeutic method of local treatment of CMV retinitis.

Transscleral iontophoresis of foscarnet

Current local treatments of cytomegalovirus retinopathy may result in serious intraocular complications. Using an animal model, we investigated transscleral iontophoresis as a technique for delivery of foscarnet to the vitreous. Using a probe tip surface area of 0.19 mm2, a current of 1 mA, and a duration of ten minutes, transscleral iontophoresis of 0.5 ml of a 24-mg/ml foscarnet solution was administered to 72 normal rabbits. Vitreous aspiration was performed at 12 intervals (15 minutes, 30 minutes, and one, two, four, eight, 16, 24, 32, 40, 48, and 60 hours) after iontophoresis, and samples were analyzed by high-performance liquid chromatography to determine the vitreous pharmacokinetics of foscarnet. A peak foscarnet concentration of 200 +/- 31 microM (mean +/- standard deviation) was attained four hours after iontophoresis and was well below the concentration reported to cause retinal toxicity. Therapeutic levels were maintained until 60 hours after iontophoresis. The elimination half-life was approximately 24 hours. No toxic effects to anterior chamber structures were observed by biomicroscopy. Transscleral iontophoresis of foscarnet may provide an effective and safe technique for local treatment of cytomegalovirus retinopathy in patients with acquired immunodeficiency syndrome.

Ocular complications of the acquired immunodeficiency syndrome. Focus on the treatment of cytomegalovirus retinitis with ganciclovir and foscarnet

The most common ocular complication in patients with the acquired immunodeficiency syndrome (AIDS) is cytomegalovirus retinitis. Incidence figures vary from 20 to 76%. Patients with cytomegalovirus may suffer from mild visual impairment of one or both eyes, but as the disease progresses the retinitis will almost certainly lead to blindness. Although cytomegalovirus retinitis is not a life-threatening infection, it can largely diminish the patient's quality of life. Clinical trials for the treatment of cytomegalovirus retinitis with a number of antiviral drugs have resulted in two drugs of choice, ganciclovir and foscarnet. Both drugs have an initial efficacy with induction therapy of 80-90%, but maintenance therapy is always needed to prevent a relapse. To exclude systemic side-effects of ganciclovir, intravitreal administration has been investigated with good results. Combination therapy of foscarnet and ganciclovir may be worthwhile in resistant cytomegalovirus retinitis.

Concurrent oral cytomegalovirus and herpes simplex virus infection in association with HIV infection. A case report

Recurrent oral herpes simplex virus lesions are common in both immunocompetent and immunocompromised persons. In contrast, cytomegalovirus-associated intraoral lesions are rarely seen, even in the immunocompromised host. We report a case of concurrent oral herpes simplex virus and cytomegalovirus infection, appearing as an ulcerative lesion of the labial mucosa in a patient with acquired immunodeficiency syndrome. Herpes simplex virus type 1 was shown to be present in the lesion by culture tests, histopathologic examination, immunohistochemistry findings and a direct immunofluorescence assay, and cytomegalovirus by histopathologic examination and immunohistochemistry findings. We deduce that the lesion was due to concurrent herpes simplex virus-1 and cytomegalovirus infection. The patient responded well to 2 weeks of treatment with a high dose of acyclovir.

Foscarnet-induced severe hypomagnesemia and other electrolyte disorders

OBJECTIVE

To report a case of possible foscarnet-induced severe hypomagnesemia and other electrolyte disorders.

CASE SUMMARY

An AIDS patient experienced an exacerbation of cytomegalovirus retinitis and was treated with foscarnet. The patient experienced muscle twitches, tremulousness, and anxiety on day 17 of foscarnet therapy. Laboratory results indicated hypomagnesemia, hypocalcemia, hypokalemia, and hypophosphatemia. After electrolyte supplementation and discontinuation of foscarnet, the symptoms resolved and laboratory indices returned to normal.

DISCUSSION

Electrolyte disorders associated with foscarnet are reviewed. Severe hypomagnesemia occurred in this patient and published literature is highlighted. In addition, known and/or possible mechanisms of the disorders are discussed.

CONCLUSIONS

It is probable that foscarnet contributed to the electrolyte disorders and symptomatology in this patient. Electrolytes must be monitored frequently during foscarnet therapy. Also, concomitant therapy with antianxiety medications that may mask the symptoms of electrolyte disorders should be undertaken with caution.

Oral CMV lesions and the HIV infected. Early recognition can help prevent morbidity

Although they are rare, oral ulcers caused by cytomegalovirus infection can occur in immunocompromised people, including those infected with HIV. Once recognized, however, oral CMV lesions can be successfully treated in most cases. Moreover, early recognition permits prompt evaluation for CMV retinitis or disseminated CMV infection, and may help prevent morbidity caused by CMV.

Increased survival of a cohort of patients with acquired immunodeficiency syndrome and cytomegalovirus retinitis who received sodium phosphonoformate (foscarnet)

PURPOSE

To evaluate the impact of foscarnet on the longevity of persons with human immunodeficiency virus, type 1 (HIV-1) infection and cytomegalovirus (CMV) retinitis.

PATIENTS AND METHODS

A cohort of 24 patients with acquired immunodeficiency syndrome (AIDS) and CMV retinitis received sodium phosphonoformate (foscarnet) as part of a controlled efficacy trial at the National Institutes of Health. Foscarnet was continued for as long as it was tolerated. Antiretroviral therapy was given to the patients as tolerated. Long-term follow-up was available on all patients.

RESULTS

Seventeen patients received zidovudine during or after receiving foscarnet, 2 patients received dideoxyinosine, 2 patients zidovudine and dideoxyinosine, and 3 patients received no specific antiretroviral agent. Patients received foscarnet for a mean of 6.2 months (median, 4 months; range, 10 days to 22 months). Ten patients required a change to ganciclovir therapy at some time after receiving foscarnet. The median time from the diagnosis of CMV retinitis until death was 13.5 months (range, 3 to 34 months). Patients lived longer than untreated or ganciclovir-treated historical controls with AIDS and CMV retinitis. There was no difference in the survival of patients treated with foscarnet at the time of diagnosis and those patients treated with foscarnet only after progression of their CMV retinitis.

CONCLUSIONS

These data suggest that foscarnet may prolong the survival of persons with AIDS and CMV retinitis and should be the initial treatment of choice in these patients.

Cytomegalovirus infection in acquired immune-deficiency syndrome

Cytomegalovirus (CMV) infection is very common in acquired immune deficiency syndrome (AIDS) with approximately 40% of patients presenting CMV visceral involvement at advanced stage disease. The most common localizations are retinitis and gastrointestinal involvement; central nervous system disorders are likely to be underestimated. Diagnosis of CMV disease should be assessed, for all localizations except retinitis, on the association of clinical symptoms with presence of CMV inclusions in biopsy specimens. Two drugs, ganciclovir and foscarnet, are currently licensed for treatment. Both are administered intravenously. Since progression of CMV disease is very common particularly in retinitis, maintenance therapy should be given throughout remaining life. Unfortunately, maintenance therapy does not entirely prevent the risk of relapses. Drug toxicity is mainly bone marrow suppression with ganciclovir and renal insufficiency with foscarnet. Since quality of life is severely impaired by long-term daily intravenous treatment, orally active drugs are urgently needed both for treatment and primary prophylaxis of CMV infection.

Management and prevention of cytomegalovirus infection after renal transplantation

We reviewed the epidemiologic characteristics, diagnosis, clinical features, and management of cytomegalovirus (CMV) infection after renal transplantation. CMV, the major viral pathogen after renal transplantation, increases patient morbidity and mortality. The spectrum of CMV infection ranges from latent infection to asymptomatic viral shedding to life-threatening multisystem disease. The two major risk factors for the development of CMV infection in renal transplant recipients are (1) preexisting CMV antibody seropositivity of either the organ donor or the recipient and (2) host immunosuppression. Blood cultures (but not urine cultures) positive for CMV predict the progression of asymptomatic infection to CMV disease, characterized by fever, malaise, myalgia, leukopenia, abnormal transaminase levels, and often involvement of the lung and gut. New genomic methods of viral detection now offer diagnostic advantages, including methods of detecting only actively replicating CMV. No evidence shows that CMV directly causes allograft rejection or glomerulonephritis, but patients with tissue-invasive CMV disease have higher rates of allograft loss and mortality than do those without the disease. Therapy for established CMV disease includes decreasing the immunosuppressive therapy and administering the antiviral agent ganciclovir sodium. Proven prophylactic strategies include limitation of exposure to the virus from CMV seropositive blood or organ donors, administration of CMV-specific immune globulin, and use of high-dose acyclovir therapy. Preemptive therapy with ganciclovir is a promising alternative to prophylaxis for patients at highest risk for progression to symptomatic CMV disease, such as those with CMV viremia and seropositive recipients receiving antilymphocyte therapy.

Treatment of herpesvirus infections in HIV-infected individuals

OBJECTIVE

To discuss strategies available for the treatment of herpesvirus infections in individuals infected with HIV.

DATA SOURCES

Information was obtained from controlled and uncontrolled clinical trials, abstracts, conference proceedings, and review articles.

STUDY SELECTION

Emphasis was placed on controlled investigations in subjects infected with HIV.

DATA EXTRACTION

Data from human studies were extracted by the author and evaluated according to the patient population studied, sample size, dosage regimen, and therapeutic response.

DATA SYNTHESIS

Herpes group viruses are common opportunistic pathogens in HIV-infected individuals. Zoster, caused by varicella-zoster virus (VZV), is an early indication of the loss of cell-mediated immunity and HIV disease progression. Anorectal mucocutaneous disease is the most common manifestation caused by herpes simplex virus (HSV). Acyclovir is the drug of choice for treatment of both VZV and HSV infections. Cytomegalovirus (CMV) is the most common life-threatening viral infection in patients with AIDS; retinitis is the most frequent clinical manifestation. The response rate of CMV retinitis to initial treatment with either ganciclovir or foscarnet is equivalent, approximately 60-90 percent. Recent data suggest that the survival benefit may be greater with foscarnet.

CONCLUSIONS

Advances in the development and application of antiviral drugs for herpes group viruses have made treatment and, in some cases, prevention of infections possible. Future efforts, aimed at earlier intervention and suppression of latent virus, may offer additional improvement in quality of life for the HIV-infected individual.

Systemic antiviral drugs used in ophthalmology

Over the past two decades, the recognition of viral enzymes and proteins that can serve as molecular targets of drugs has revolutionized the treatment of viral infections. Beginning with acyclovir, a number of systemically administered agents which are both relatively safe and effective for the treatment of herpetic infections and human immunodeficiency virus (HIV) infections have become widely available. Because of increased numbers of herpes virus infections, as well as the rising epidemic of HIV infections, the ophthalmologist is, more likely than ever before to be involved in the treatment of severe and frequent ocular infections caused by herpes viruses. In addition, the acute retinal necrosis (ARN) syndrome has been demonstrated to be caused by herpes viruses and a once rare retinal infection caused by cytomegalovirus is common in patients with the acquired immunodeficiency syndrome (AIDS). In this article, four systemic antiviral drugs (Vidarabine, Acyclovir, Ganciclovir, and Foscarnet) that have demonstrated usefulness in the treatment of ophthalmic disease are reviewed in detail with regard to their mechanisms, applications, effectiveness, and side effects.

Delivery of Infusion Therapies in the Home for Patients With Acquired Immunodeficiency Syndrome

Patients with acquired immunodeficiency syndrome (AIDS) often suffer from a variety of infectious and noninfectious complications as a result of their compromised immune status. Therapies that AIDS patients may require include antimicrobial therapy, parenteral nutrition, pain management, chemotherapy, and agents to regulate hematopoiesis. Although parenteral therapies have been more traditionally administered in a hospital, technological advances, economic advantages, and patient and clinician acceptance have helped establish home infusion therapy as a viable alternative for many patients with a chronic disease such as AIDS. Providing pharmaceutical care in the home care arena to patients with AIDS not only involves patient monitoring and parenteral product preparation, but also a thorough understanding of infection control practices. Working in conjunction with other health care professionals, pharmacists play a major role in helping to assure the safe and effective delivery of the complex therapies required by many patients with AIDS in the comfort of their homes.

Antiviral therapy: current concepts and practices

Drugs capable of inhibiting viruses in vitro were described in the 1950s, but real progress was not made until the 1970s, when agents capable of inhibiting virus-specific enzymes were first identified. The last decade has seen rapid progress in both our understanding of antiviral therapy and the number of antiviral agents on the market. Amantadine and ribavirin are available for treatment of viral respiratory infections. Vidarabine, acyclovir, ganciclovir, and foscarnet are used for systemic treatment of herpesvirus infections, while ophthalmic preparations of idoxuridine, trifluorothymidine, and vidarabine are available for herpes keratitis. For treatment of human immunodeficiency virus infections, zidovudine and didanosine are used. Immunomodulators, such as interferons and colony-stimulating factors, and immunoglobulins are being used increasingly for viral illnesses. While resistance to antiviral drugs has been seen, especially among AIDS patients, it has not become widespread and is being intensely studied. Increasingly, combinations of agents are being used: to achieve synergistic inhibition of viruses, to delay or prevent resistance, and to decrease dosages of toxic drugs. New approaches, such as liposomes carrying antiviral drugs and computer-aided drug design, are exciting and promising prospects for the future.

Maintenance therapy for cytomegalovirus retinitis in patients with acquired immunodeficiency syndrome: foscarnet

The use of ganciclovir in the treatment of cytomegalovirus (CMV) retinitis in patients with acquired immunodeficiency syndrome (AIDS) is limited by marrow toxicity and by the development of resistance to this agent in CMV strains capable of causing progressive disease. Foscarnet retains activity against ganciclovir-resistant CMV and has an adverse effect profile different from that of ganciclovir. Preliminary data from studies conducted under the AIDS Clinical Trials Group (ACTG) program indicate that intravenous foscarnet maintenance therapy at 60, 90, and 120 mg/kg/day in AIDS patients with CMV retinitis successfully completing foscarnet induction therapy is associated with median times to retinitis progression of 90, 95, and greater than 123 days, respectively. An ACTG trial of foscarnet in patients failing ganciclovir therapy has been initiated, as has a trial jointly sponsored by the National Eye Institute and the National Institute of Allergy and Infectious Diseases comparing the safety and efficacy of foscarnet and ganciclovir. Also underway is a trial evaluating the effects of combination and alternating regimens of these two agents.

Design of a randomized controlled trial of foscarnet in patients with cytomegalovirus retinitis associated with acquired immunodeficiency syndrome

In a controlled trial of foscarnet in the treatment of cytomegalovirus (CMV) retinitis in patients with the acquired immunodeficiency syndrome (AIDS), patients with non-immediately sight-threatening lesions were randomized to receive immediate treatment with foscarnet or foscarnet treatment delayed until the first signs of retinitis progression. Foscarnet induction therapy was administered at a dosage of 60 mg/kg 3 times/day via 1-hour intravenous infusion for 21 days. Foscarnet maintenance therapy was administered at a dosage of 90 mg/kg/day via 2-hour infusion. Foscarnet was well tolerated and effective in delaying progression of CMV retinitis in these patients. Final analysis of data from this study and data from other studies will help to determine what role foscarnet will have in the treatment of CMV retinitis in patients with AIDS.

Mortality in patients with the acquired immunodeficiency syndrome treated with either foscarnet or ganciclovir for cytomegalovirus retinitis

BACKGROUND AND METHODS

We performed a multicenter, randomized, unblinded clinical trial (the Foscarnet-Ganciclovir Cytomegalovirus Retinitis Trial) designed to compare ganciclovir with foscarnet in the treatment of cytomegalovirus retinitis in patients with the acquired immunodeficiency syndrome (AIDS). Of 234 patients, 127 were randomly assigned to ganciclovir and 107 to foscarnet; the study drugs were administered according to a common protocol at the 11 participating clinical centers. Antiretroviral therapy (with zidovudine, didanosine, or dideoxycytidine) was given as dictated by best medical judgment. The patients were followed for the progression of retinitis, visual loss, and death.

RESULTS

Excess mortality in the ganciclovir group (as compared with the foscarnet group) led the Policy and Data Monitoring Board to recommend suspension of the treatment protocol 19 months after the trial started. As of that time, 65 of the patients assigned to ganciclovir had died, as compared with 36 of those assigned to foscarnet (51 percent vs. 34 percent, P = 0.007; relative risk, 1.79; 95 percent confidence interval, 1.17 to 2.73). The median survival was 8.5 months in the ganciclovir group and 12.6 months in the foscarnet group. Although the patients assigned to ganciclovir received less antiretroviral therapy on average than those assigned to foscarnet, the excess mortality could not be explained entirely by differences in exposure to antiretroviral drugs. In the forscarnet group, the only subgroup of patients identified as having excess mortality were those whose renal function was compromised at entry. There was no difference between the two treatment groups in the rate of progression of retinitis (relative risk, 0.95; P = 0.751).

CONCLUSIONS

These results suggest that for patients with AIDS, and cytomegalovirus retinitis, treatment with foscarnet offers a survival advantage over treatment with ganciclovir, although the patients may not tolerate foscarnet as well as ganciclovir.