Loss of cytomegalovirus-specific CD4+ T cell responses in human immunodeficiency virus type 1-infected patients with high CD4+ T cell counts and recurrent retinitis.

Clinical histories are reported for 2 patients treated with highly active antiretroviral therapy (HAART) who experienced multiple relapses of cytomegalovirus (CMV) retinitis, despite suppression of human immunodeficiency virus type 1 (HIV-1) viremia and improvement in CD4+ T cell counts (to >400 cells/microL). CMV-specific CD4+ T cell immune reconstitution was measured directly, using cytokine flow cytometry, which revealed persistent deficits in CMV-specific CD4+ T cell responses in both patients. CMV-specific T cells constituted 0.14% and 0.05% of the total CD4+ T cell count in these patients, which is significantly lower than the percentages for 34 control subjects (0.6%-46%; CD4+ T cell count range, 7-1039 cells/microL; P=.019). Deficits in pathogen-specific immune responses may persist in some individuals, despite suppression of HIV-1 replication and substantial increases in circulating CD4+ T cells after HAART, and such deficits may be associated with significant morbidity from opportunistic infections.

Low-dose daily subcutaneous interleukin-2 in combination with highly active antiretroviral therapy in HIV+ patients: a randomized controlled trial.

PURPOSE: Previous studies with intermittent interleukin-2 (IL-2) therapy using intermediate and high levels of IL-2 have demonstrated significant increases in the CD4 + T cell count in HIV-infected patients. Intermittent regimens are amenable to outpatient use, but severe adverse events are frequently experienced with intermediate- and high-dose levels of IL-2. Therefore in this study, the effect of daily, subcutaneous low-dose IL-2 therapy on safety and immunological endpoints was investigated to determine whether immunological benefit could be achieved without toxicity in HIV-infected patients also receiving highly active antiretroviral therapy (HAART). METHOD: A total of 115 patients were enrolled in the trial. Fifty-six asymptomatic HIV-infected patients who had CD4 + T cell counts less than 300 cells/microL at screening and a stable HIV viral load received low-dose IL-2 (1.2 million IU [MIU]/m 2 beginning dose) once daily in conjunction with HAART (IL-2 group). Fifty-nine patients received HAART alone (control group). RESULTS: A dramatic effect of IL-2 on the natural killer (NK) cell population was observed with mean increases of 156 cells/microL in the IL-2 group compared to 19.93 cells/microL in the control group (p <.001). Additionally, IL-2-treated patients experienced a statistically significant increase in the mean percentage of CD4 + T cells (3.52% increase) when compared to control patients (1.33% increase) (p <.001). The expanded CD4 + T cell population was primarily of the naive phenotype, with mean increases of 4.53% for the IL-2 group and 0.31% for the control group (p <.001 for between-group difference). In addition, a higher proportion of IL-2-treated patients (67%) compared to control patients (33%) achieved increases of greater than 50% in the CD4+ T cell count (p =.08). Adverse events of grade 3 or grade 4 toxicity were infrequent in the current study and were substantially lower by comparison to those in studies of intermittent dose IL-2 therapy. Also, negligible changes in the HIV viral load from baseline to final measurement were observed in both groups. A trend toward a reduced number of modifications of antiretroviral therapy was apparent in the IL-2 group when compared to control patients. CONCLUSION: Daily, low-dose subcutaneous IL-2 therapy in conjunction with HAART is safe and well tolerated and is effective in expanding lymphocyte cell types including NK cells and naive T cells in individuals who have <300 CD4+ T cells.

In vitro antiviral susceptibilities of isolates from cytomegalovirus retinitis patients receiving first- or second-line cidofovir therapy: relationship to clinical outcome.

Blood culture isolates from patients receiving first- (peripheral retinitis) or second-line (relapsing retinitis) therapy with intravenous cidofovir were obtained from three clinical trials for in vitro antiviral susceptibility analyses. Isolates from 6 patients obtained after 14.3 weeks (mean) of first-line cidofovir therapy showed complete susceptibility to cidofovir, ganciclovir, and foscarnet. Isolates from 20 patients were obtained after 17.3 weeks (mean) of second-line cidofovir therapy. Ten showed complete susceptibility to all inhibitors, 3 showed low-level ganciclovir resistance (<6-fold) but were sensitive to cidofovir and foscarnet, and 7 showed moderately reduced susceptibility (<8-fold) to cidofovir and high-level resistance (8- to 23-fold) to ganciclovir in vitro. Four of these 7 isolates showed reduced susceptibility (4-fold) to foscarnet. Notably, there was no difference in time to retinitis progression in patients that were on cidofovir therapy when sensitive isolates were compared with those showing reduced susceptibility to cidofovir in vitro.

Sorivudine versus acyclovir for treatment of dermatomal herpes zoster in human immunodeficiency virus-infected patients: results from a randomized, controlled clinical trial. Collaborative Antiviral Study Group/AIDS Clinical Trials Group, Herpes Zoster Study Group.

The present randomized, double-blind, placebo-controlled, multicenter clinical trial was designed to compare the efficacy and tolerability of sorivudine [1-beta-D-arabinofuranosyl-E-(2-bromovinyl)uracil] and acyclovir for the treatment of dermatomal herpes zoster in human immunodeficiency virus (HIV)-seropositive patients. A total of 170 HIV-seropositive adults presenting with herpes zoster (confirmed by direct fluorescent-antigen testing and/or viral culture) were enrolled and randomized to receive a 10-day course of orally administered sorivudine (40 mg once daily plus acyclovir placebos) or acyclovir (800 mg five times daily plus sorivudine placebo). Patients were monitored daily to document the events of cutaneous healing, pain, zoster-related complications, and drug-related adverse events. Patients were reassessed on days 21 and 28 and then once monthly for 1 year. The primary efficacy endpoint was time to the cessation of new vesicle formation. Secondary efficacy endpoints included times to other events of cutaneous healing, resolution of pain, and frequency of dissemination and zoster recurrence. In a multivariate analysis, sorivudine was superior to acyclovir for reducing the times to the cessation of new vesicle formation (relative risk [RR] = 1.54, 95% confidence interval [CI] = 1.00 to 2.36; P = 0.049) and total lesion crusting (RR = 1.48, 95% CI = 1.07 to 2.04; P = 0.017). In a univariate analysis, there was a trend favoring sorivudine for the cessation of new vesicle formation (median of 3 versus 4 days; P = 0.07) and a significant advantage for time to total lesion crusting (median of 7 versus 8 days; P = 0.02). The time to the resolution of zoster-associated pain, the frequency of dissemination, and the frequency of zoster recurrence were not different between the two treatment groups. Both drugs were well tolerated. Sorivudine is an effective drug for the treatment of herpes zoster in HIV-infected patients and results in accelerated cutaneous healing when compared with acyclovir therapy.

Randomized, controlled study of the safety and efficacy of intravenous cidofovir for the treatment of relapsing cytomegalovirus retinitis in patients with AIDS.

To assess the effect of intravenous cidofovir on delaying progression of previously treated, relapsing cytomegalovirus (CMV) retinitis, we conducted a randomized, controlled comparison of two maintenance dose levels of cidofovir. One hundred and fifty patients with AIDS and CMV retinitis that had progressed or was persistently active despite treatment with ganciclovir, foscarnet, or both were randomized to receive induction cidofovir, 5 mg/kg once weekly for 2 weeks, then maintenance therapy with either 5 mg/kg or 3 mg/kg once every other week. Concomitant probenecid and intravenous hydration were administered with each cidofovir dose. Retinitis progression was assessed in the first 100 patients by bilateral, full-field retinal photographs read at a central reading center by an ophthalmologist masked to treatment assignment. Incidence of side effects, changes in visual acuity, and mortality were also assessed. Median time to retinitis progression as assessed by retinal photography was not reached (95% confidence interval [CI], 115 days-upper limit not reached) in the 5-mg/kg group, and was 49 days (95% CI, 35-52 days) in the 3-mg/kg group (p = .0006). Dose-dependent asymptomatic proteinuria (39%) and serum creatinine elevation (24%) were the most common adverse events thought to be related to cidofovir. Reversible probenecid reactions including constitutional symptoms and nausea occurred in 65 of 150 (43%) patients. Cidofovir therapy is effective in delaying progression of CMV retinitis that had previously progressed using other anti-CMV therapies.

Quantification of cytomegalovirus DNA in peripheral blood leukocytes by a branched-DNA signal amplification assay.

Quantification of cytomegalovirus (CMV) DNA in blood may aid in the identification of patients at highest risk for developing CMV disease, the evaluation of new therapeutics, and the prompt recognition of drug-resistant CMV strains. A branched-DNA (bDNA) assay was developed for the reliable quantification of CMV DNA in peripheral blood leukocytes. The bDNA assay allowed for the highly specific and reproducible quantification of CMV DNA in clinical specimens. Furthermore, the bDNA assay was at least as sensitive as culture techniques and displayed a nearly 3 log10 dynamic range in quantification. Changes in CMV DNA levels measured by the bDNA assay in a human immunodeficiency virus-positive patient undergoing therapy were consistent with CMV culture, antigen, and genotype results and correlated with disease progression and resistance markers. The bDNA assay for the quantification of CMV DNA may provide a useful tool that can be used to aid physicians in monitoring disease progression, evaluating therapeutic regimens, and recognizing viral resistance and drug failure.

Evolution of mutations conferring multidrug resistance during prophylaxis and therapy for cytomegalovirus disease.

In a human immunodeficiency virus-infected subject, cytomegalovirus (CMV) isolated 9 months after the patient began oral ganciclovir prophylaxis was resistant to ganciclovir and cidofovir and contained mutations in both UL97 and Pol coding regions. At 1 year, retinitis developed, which progressed despite intravenous ganciclovir followed by foscarnet and then cidofovir. A subsequent buffy coat virus isolate was resistant to all three drugs and contained new mutations in UL97 and Pol. By individually transferring the observed mutations to laboratory strain AD169, it was shown that a mutation at codon 603 of UL97 conferred resistance to ganciclovir, a mutation at codon 412 of Pol conferred resistance to both ganciclovir and cidofovir, and a mutation at codon 802 of Pol conferred resistance to ganciclovir and foscarnet. This case illustrates the development of multidrug resistance during prolonged exposure to antiviral therapy for CMV and cross-resistance arising from point mutations in the CMV Pol gene.

Intravenous cidofovir for peripheral cytomegalovirus retinitis in patients with AIDS. A randomized, controlled trial.

BACKGROUND: Cytomegalovirus (CMV) retinitis is the most common intraocular infection in patients with the acquired immunodeficiency syndrome (AIDS). If left untreated, it may lead to progressive destruction of retinal tissue and blindness. Cidofovir is a nucleotide analogue of cytosine that has potent, prolonged in vitro and in vivo activity against herpesviruses, including many CMV isolates that are resistant to ganciclovir and foscarnet. OBJECTIVE: To determine whether intravenous cidofovir delays progression of previously untreated CMV retinitis. DESIGN: Randomized, controlled trial comparing immediate with deferred cidofovir treatment. Patients in the deferred treatment group were eligible to receive cidofovir after progression of CMV retinitis was documented by retinal photography. SETTING: Eight academic medical centers and an independent center that read retinal photographs. PATIENTS: 48 patients with AIDS and previously untreated peripheral CMV retinitis who were randomly assigned to immediate (n = 25) or deferred treatment (n = 23). INTERVENTION: Intravenous cidofovir, 5 mg/kg of body weight, once weekly for 2 weeks and then once every other week. To minimize nephrotoxicity, oral probenecid and intravenous hydration with normal saline were administered with each cidofovir infusion. MEASUREMENTS: Progression of CMV retinitis was assessed by bilateral, full-field retinal photographs that were read by an ophthalmologist who was masked to treatment assignment. Incidence of side effects, changes in visual acuity, effect on CMV shedding in urine and blood, and mortality were also assessed. RESULTS: The median time to progression of CMV retinitis was 22 days (95% CI, 10 to 27 days) in the deferred treatment group and 120 days (CI, 40 to 134 days) in the immediate treatment group (P < 0.001). Neutropenia (15%) and proteinuria (12%), both asymptomatic, were the most common serious adverse events considered to be possibly related to cidofovir. Cidofovir treatment was discontinued in 10 of 41 patients (24%) because of protocol-defined treatment-limiting nephrotoxicity. Transient reactions to probenecid, including mild to moderate constitutional symptoms or nausea, occurred in 23 of 41 patients (56%) and were dose limiting in 3 (7%). CONCLUSIONS: Cidofovir was efficacious in delaying progression of previously untreated CMV retinitis. Treatment was associated with manageable side effects; strict adherence to monitoring of renal function before cidofovir was administered and concomitant administration of probenecid and saline hydration appeared to minimize drug-related nephrotoxicity.

Cidofovir: a new therapy for cytomegalovirus retinitis.

Cidofovir, (S)-1-[3-hydroxy-2-(phosphonylmethoxy)propyl]cytosine, formerly known as HPMPC, is the first antiviral nucleotide analogue available for the treatment of cytomegalovirus (CMV) retinitis. Because cidofovir does not require viral activation, it has two advantages over nucleoside analogues such as ganciclovir and acyclovir. Cidofovir is active in uninfected cells and may act preemptively, and it may retain activity against ganciclovir-resistant strains. Preclinical studies showed the major toxicity of cidofovir to be dose-, schedule-, and species-dependent nephrotoxicity. These studies also showed that concomitant administration of probenecid protects animal models against cidofovir-induced nephrotoxicity. Two phase I-II studies were undertaken in HIV-positive patients with asymptomatic CMV excretion to evaluate several dose-escalation regimens. Data from both phase I-II studies showed that in patients receiving cidofovir at > or =3 mg/kg, the virologic response rate (> or =2 log reduction in CMV titer) was 93% for urine and 74% for semen. In addition, four treatment modifications were indicated to reduce the incidence of cidofovir-related nephrotoxicity: (a) dose reduction or interruption for changes in renal function; (b) concomitant administration of probenecid; (c) administration of 1 L of normal saline 1 h before infusion of cidofovir; and (d) extension of the dosing interval.

Clinical experience with cidofovir in the treatment of cytomegalovirus retinitis.

Cidofovir (Vistide, HPMPC) is a nucleotide analogue with potent in vitro activity against cytomegalovirus (CMV) that was recently licensed for treatment of patients with acquired immunodeficiency syndrome (AIDS) and CMV retinitis. Cidofovir's prolonged intracellular half-life permits dosing once every 2 weeks for maintenance treatment. The treatment-limiting toxicity of cidofovir is dose- and schedule-dependent nephrotoxicity affecting renal proximal convoluted tubule cells. A treatment regimen that includes concomitant administration of oral probenecid, intravenous hydration, and careful preinfusion evaluation of renal function with conservative dose modification has reduced cidofovir-associated nephrotoxicity. Preliminary results of clinical studies of cidofovir in AIDS patients with newly diagnosed and relapsing CMV retinitis are described.

Oral ganciclovir for the prevention of cytomegalovirus disease in persons with AIDS. Roche Cooperative Oral Ganciclovir Study Group.

BACKGROUND: In the advanced stages of the acquired immunodeficiency syndrome (AIDS), cytomegalovirus (CMV) disease, particularly vision-damaging retinitis due to CMV is common. We evaluated prophylactic treatment with orally administered ganciclovir as a way to prevent CMV disease. METHODS: We conducted a prospective, randomized, double-blind, placebo-controlled study of CMV infected persons with AIDS with either CD4+ lymphocyte counts of < or = 50 per cubic millimeter or counts of < or = 100 per cubic millimeter in those with a history of an AIDS defining opportunistic infection. Patients were randomly assigned, in a 2:1 ratio, to receive either oral ganciclovir (1000 mg three times daily) or placebo. RESULTS: The study was stopped after a median 367 days of follow-up. In an intention-to-treat analysis, the twelve month cumulative rates of confirmed CMV disease were 26 percent in the placebo group (n = 239) and 14 percent in the ganciclovir group (n = 486), representing an overall reduction in risk of 49 percent in the ganciclovir group (P < 0.001). The incidence of CMV retinitis after 12 months was 24 percent in the placebo group and 12 percent in the ganciclovir group (P < 0.0001). The prevalence of CMV-positive urine cultures at base line was 42 percent; after two months it was 43 percent in the placebo group and 10 percent in the ganciclovir group (P < 0.0001). The one year mortality rate was 26 percent in the placebo group and 21 percent in the ganciclovir group (P = 0.14). Therapy with granulocyte colony stimulating factor was more frequent in the ganciclovir group (24 percent) than in the placebo group (9 percent). CONCLUSIONS: In persons with advanced AIDS, phophylactic oral ganciclovir significantly reduces the risk of CMV disease.

Susceptibility of human cytomegalovirus to cidofovir is unchanged after limited in vivo exposure to various regimens of drug.

Cidofovir [1-[(S)-3-hydroxy-2-(phosphonomethoxy)propyl]cytosine] susceptibility among 29 paired pre- and post-cidofovir exposure isolates from 22 patients enrolled in phase I/II clinical trial, GS-92-101, was determined. This trial was designed to evaluate the safety and antiviral effects of cidofovir in patients with AIDS and asymptomatic shedding of human cytomegalovirus (HCMV) in semen with no evidence of end-organ HCMV disease and no prior anti-HCMV therapy. These patients received a median cumulative dose of 30 mg/kg (range, 3-67) administered over a median of 8 weeks (range, 2-38). The IC50 values of preexposure isolates ranged from <0.5 to 1.85 and for postexposure isolates from <0.5 to 2 uM. Thus, no significant changes in cidofovir susceptibilities have been noted for HCMV during the various regimens of cidofovir administrated in this clinical trial.

Quantification of zidovudine and individual zidovudine phosphates in peripheral blood mononuclear cells by a combined isocratic high performance liquid chromatography radioimmunoassay method.

Zidovudine (ZDV, AZT) is the first clinically effective drug licensed for use in the treatment of human immunodeficiency virus (HIV) infection. Activation of ZDV requires phosphorylation to ZDV triphosphate by cellular kinases. It is important, therefore, to determine the intracellular levels of the active form because measurement of ZDV concentrations in plasma have not reflected any direct relationship with activity or toxicity. In this paper a validated assay for the measurement of both ZDV and its three phosphorylated anabolites, ZDV mono-, di- and triphosphate, in peripheral blood mononuclear cells (PBMCs) is described. The method consisted of a combination of isocratic high performance liquid chromatography (HPLC) separation and radioimmunoassay (RIA). The PBMCs were separated from whole blood and ZDV and ZDV nucleotides were extracted and separated by isocratic elution with an ion-pairing mobile phase on a reversed-phase HPLC column. The collected ZDV and individual ZDV nucleotide fractions were dephosphorylated to ZDV, cleaned by solid phase extraction and assayed by a commercially available RIA kit. The assay developed was successfully used to determine intracellular ZDV and anabolite concentrations of 10 PBMC samples taken from HIV positive patients on ZDV treatment.

Population differences in ganciclovir clearance as determined by nonlinear mixed-effects modelling.

We examined the pharmacokinetics of ganciclovir in different populations of cytomegalovirus (CMV)-infected patients through the use of nonlinear mixed-effects modelling. As expected, patient weight and estimated creatinine clearance were shown to be important covariates in the serum ganciclovir clearance. Unexpectedly, major differences in ganciclovir clearance between different populations of patients were found. Human immunodeficiency virus (HIV)-infected patients with CMV retinitis cleared ganciclovir 41% faster than HIV-infected patients only shedding CMV into the urine. Solid-organ transplant patients had a serum clearance one-fourth that of HIV-infected patients, even with correction for creatinine clearance. These findings require prospective validation and may have important implications for ganciclovir dosing in different populations of CMV-infected patients.

Oral ganciclovir as maintenance treatment for cytomegalovirus retinitis in patients with AIDS. Syntex Cooperative Oral Ganciclovir Study Group.

BACKGROUND: Cytomegalovirus retinitis, a sight-threatening infection associated with the acquired immunodeficiency syndrome (AIDS), currently requires lifelong intravenous treatment. An effective oral treatment would be an important advance. METHODS: We compared oral with intravenous ganciclovir in an open-label, randomized study in patients with AIDS and newly diagnosed, stable cytomegalovirus retinitis (the disease was stabilized by three weeks of treatment with intravenous ganciclovir). Sixty subjects were randomly assigned to maintenance therapy with intravenous ganciclovir at a dose of 5 mg per kilogram of body weight daily, and 63 to maintenance therapy with oral ganciclovir at a dose of 3000 mg daily. The subjects were followed for up to 20 weeks, with photography of the fundi conducted every other week. The photographs were evaluated at the completion of the study by an experienced grader who was unaware of the subjects' treatment assignments. RESULTS: Efficacy could be evaluated in 117 subjects; photographs were ungradable for 2 of the 117. On the basis of the masked assessment of photographs from 115 subjects, the mean time to the progression of retinitis was 62 days in those given intravenous ganciclovir and 57 days in those given oral ganciclovir (P = 0.63; relative risk [oral vs. intravenous], 1.08; 95 percent confidence interval for the difference in means, -22 to +12 days). On the basis of funduscopy by ophthalmologists who were aware of the subjects' treatment assignments, the mean time to progression was 96 days in subjects given intravenous ganciclovir and 68 days in subjects given oral ganciclovir (P = 0.03; relative risk [oral vs. intravenous], 1.68; 95 percent confidence interval for the difference in means, -45 to -11 days). Survival, changes in visual acuity, the incidence of viral shedding, and the incidence of adverse gastrointestinal events were similar in the two groups. Neutropenia, anemia, intravenous-catheter-related adverse events, and sepsis were more common in the group given intravenous ganciclovir. CONCLUSIONS: Oral ganciclovir is safe and effective as maintenance therapy for cytomegalovirus retinitis and is more convenient for patients to take than intravenous ganciclovir.

Pharmacokinetic, safety, and antiviral profiles of oral ganciclovir in persons infected with human immunodeficiency virus: a phase I/II study. AIDS Clinical Trials Group, and Cytomegalovirus Cooperative Study Group.

A phase I/II study evaluated the pharmacokinetics, tolerability, and antiviral activity of oral ganciclovir in persons infected with human immunodeficiency virus (HIV). Oral bioavailability ranged from 2.6% to 7.3%. The mean maximum serum concentration achieved at 1000 mg every 8 h was 1.11 micrograms/mL, and mean trough level was 0.54 microgram/mL. The time to maximum serum drug concentration was 1.0-2.9 h, with a serum half-life of 3.0-7.3 h, suggesting prolonged oral absorption. Serious adverse events were uncommon. Decreased cytomegalovirus (CMV) shedding was observed from all sites. The median days (by dosage) to retinitis progression assessed by retinal examination after initiation of oral ganciclovir were 62 (1000 mg every 8 h), 148 (500 mg every 3 h), 75 (750 mg every 3 h), 148 (1000 mg every 3 h), and 139 (2000 mg every 8 h). Thus, oral ganciclovir has pharmacokinetic, toxicity, and antiviral profiles that may prove beneficial for both maintenance therapy of CMV retinitis and prevention of CMV disease in HIV-infected persons.