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

Controlling viral inflammatory lesions by rebalancing immune response patterns

In this review, we discuss a variety of immune modulating approaches that could be used to counteract tissue-damaging viral immunoinflammatory lesions which typify many chronic viral infections. We make the point that in several viral infections the lesions can be largely the result of one or more aspects of the host response mediating the cell and tissue damage rather than the virus itself being directly responsible. However, within the reactive inflammatory lesions along with the pro-inflammatory participants there are also other aspects of the host response that may be acting to constrain the activity of the damaging components and are contributing to resolution. This scenario should provide the prospect of rebalancing the contributions of different host responses and hence diminish or even fully control the virus-induced lesions. We identify several aspects of the host reactions that influence the pattern of immune responsiveness and describe approaches that have been used successfully, mainly in model systems, to modulate the activity of damaging participants and which has led to lesion control. We emphasize examples where such therapies are, or could be, translated for practical use in the clinic to control inflammatory lesions caused by viral infections.

Cytomegalovirus viremia and advanced HIV disease: is there an argument for anti-CMV treatment?

INTRODUCTION

The role of cytomegalovirus (CMV) infection as a co-factor in HIV disease has been a topic of considerable interest since the beginning of the HIV pandemic. CMV is believed to function both as a co-factor in the progression of HIV infection, and as a contributor to enhanced disease for other opportunistic infections.

AREAS COVERED

In this special article, we review several recent studies that have enhanced our understanding of the role that CMV infection plays in the natural history of other HIV-related opportunistic infections. We review the clinical evidence that demonstrates how CMV viremia has emerged as an independent risk factor for the progression of infections such as those caused by C. neoformans and M. tuberculosis. We outline the biological underpinnings of the various hypotheses by which CMV, as an immunomodulatory virus, may modify the natural history of HIV-related infections.

EXPERT OPINION

Evidence suggests that active CMV replication, manifest as CMV viremia (DNAemia), may play a key role in driving progression of HIV-associated opportunistic infections. We propose that control of CMV replication, independent of the known benefit of HAART therapy on reducing CMV end-organ disease, could reduce the risk of disease and mortality attributable to opportunistic infections such as cryptococcosis and tuberculosis. This could be achieved by the targeted use of CMV antivirals. The advent of newer (and safer) orally bioavailable CMV antivirals has renewed interest in, and opportunities for, randomized controlled trials to evaluate CMV viremia as a modifiable risk factor in high-risk persons with HIV disease.

Anti-cytomegalovirus preemptive therapy to prevent cytomegalovirus disease in HIV-infected patients: a systematic review

BACKGROUND

HIV patients are at higher risk of contracting and developing into an asymptomatic form of CMV infection. This review aimed to evaluate the efficacy and safety of preemptive therapy for preventing CMV disease in HIV patients.

METHODS

The electronic search was conducted in MEDLINE/PubMed and CENTRAL from inception until 9 September 2022. Studies were included if they assessed the efficacy or safety of anti-CMV preemptive therapy compared to placebo or no therapy. Risk of bias were assessed using the Cochrane Risk of Bias tool for randomized trials version 2 or the Cochrane Collaboration Risk of Bias in Non-randomized Studies of Interventions. The random-effects model was used to calculate effect sizes.

RESULTS

We identified six RCTs (2135 participants) and four observational studies (395 participants), with five RCTs were performed before highly active antiretroviral therapy (HAART) era. Preemptive therapy did not reduce the incidence of CMV disease (RR 0.84, 95% CI: 0.59-1.18), yet reduced the RR of all-cause mortality rate by 26% (RR 0.85, 95% CI: 0.74-0.97) with a low quality of evidence. The incidence of neutropenia as an adverse event increased significantly (RR 2.47, 95% CI: 1.12-5.45) with moderate quality of evidence.

CONCLUSIONS

With the advent of HAART, a limited number of studies have been performed to explore anti-CMV preemptive therapy due to the improved outcomes of HIV patients with CMV viremia. Therefore, optimal HAART should take precedence over anti-CMV preemptive therapy. The protocol for this review was registered in the Prospective Register of Systematic Reviews (CRD42020145765).

Cytomegalovirus viremia and risk of disease progression and death in HIV-positive patients starting antiretroviral therapy

OBJECTIVE

The aim of this study was to assess the prevalence of cytomegalovirus (CMV) viremia in HIV-positive patients starting antiretroviral therapy (ART) and to evaluate its impact on clinical outcomes.

DESIGN

A retrospective analysis of four clinical trials (INSIGHT FIRST, SMART, START, and ANRS REFLATE TB).

METHODS

Stored plasma samples from participants were used to measure CMV viremia at baseline prior to initiating ART and at visits through 1 year of follow-up after ART initiation. CMV viremia was measured centrally using a quantitative PCR assay. Within FIRST, associations of CMV viremia at baseline and through 8 months of ART were examined with a composite clinical outcome of AIDS, serious non-AIDS events, or death using Cox proportional hazards regression.

RESULTS

Samples from a total of 3176 participants, 1169 from FIRST, 137 from ANRS REFLATE TB, 54 from SMART, and 1816 from START were available with baseline CMV viremia prevalence of 17, 26, 0, and 1%, respectively. Pooled across trials, baseline CMV viremia was associated with low CD4 + T-cell counts and high HIV RNA levels. In FIRST, CMV viremia was detected in only 5% of participants between baseline and month 8. After adjustment for CD4 + T-cell count and HIV RNA levels, hazard ratios for risk of clinical outcomes was 1.15 (0.86-1.54) and 2.58 (1.68-3.98) in FIRST participants with baseline and follow-up CMV viremia, respectively.

CONCLUSION

Baseline CMV viremia in HIV-positive patients starting ART is associated with advanced infection and only persistent CMV viremia after ART initiation is associated with a higher risk of morbidity and mortality.

Immune Reconstitution Inflammatory Syndrome Associated Kaposi Sarcoma

People living with HIV (PLWH) with advanced immunosuppression who initiate antiretroviral therapy (ART) are susceptible to the occurrence of an immune reconstitution inflammatory syndrome (IRIS). Although ART is responsible for AIDS- associated Kaposi sarcoma (KS) improvement and resolution, new onset (unmasking KS-IRIS) or sudden progression of preexisting KS (paradoxical KS-IRIS) can occur after a time delay of between a few days and 6 months after the initiation or resumption of ART, even in patients with a low degree of immunocompromise. KS-IRIS incidence varies from 2.4% to 39%, depending on study design, populations, and geographic regions. Risk factors for developing KS-IRIS include advanced KS tumor stage (T1), pre-treatment HIV viral load >5 log10 copies/mL, detectable pre-treatment plasma-KSHV, and initiation of ART alone without concurrent chemotherapy. Both paradoxical and unmasking KS-IRIS have been associated with significant morbidity and mortality, and thrombocytopenia (<100,000 platelets/mm3 at 12 weeks) has been associated with death. KS-IRIS is not to be considered as ART failure, and an ART regimen must be pursued. Systemic chemotherapy for KS in conjunction with ART is recommended and, in contrast with management of IRIS for other opportunistic infections, glucocorticoids are contra-indicated. Despite our preliminary results, the place of targeted therapies in the prevention or treatment of KS-IRIS needs further assessment.

Cytomegalovirus viremia and clinical outcomes in Kenyan children diagnosed with HIV in hospital

BACKGROUND

Cytomegalovirus (CMV) viremia is common in HIV infection, and is associated with worse long-term outcomes. To date, no studies have assessed CMV viremia in children diagnosed with HIV in hospital.

METHODS

We studied CMV viremia and clinical outcomes in 163 Kenyan children aged 2 months-12 years, diagnosed with HIV in hospital. CMV DNA levels in plasma were measured using quantitative PCR. Regression models were used to assess associations between CMV viremia >1000 IU/mL and the risk of continued hospitalization or death at 15 days, duration of hospitalization, and 6-month mortality.

RESULTS

At enrollment, 62/114 (54%) children had CMV viremia, and 20 (32%) were >1000 IU/mL. Eleven CMV reactivations were observed after admission. The prevalence and level of CMV viremia were highest in children <2 years and lowest in children >5 years old. CMV viremia >1000 IU/mL was independently associated with age < 2 years (p=0.03), higher log10 HIV RNA level (p=0.01), and height-for-age z score <-2 (p=0.02). Adjusting for age and log10 HIV RNA, the relative risk of death or continued hospitalization at 15 days was 1.74 (95%CI=1.04, 2.90), and the hazard ratio of 6-month mortality was 1.97 (95%CI=0.57, 5.07) for children with CMV DNA ≥1000 IU/ml compared to lower-level or undetectable CMV DNA. Children with CMV DNA ≥1000 IU/ml were hospitalized a median ~5 days longer than children with lower-level or undetectable CMV DNA (p=0.002).

CONCLUSIONS

In this nested observational study, CMV viremia was common in hospitalized children with HIV, and levels ≥1000 IU/mL were associated with increased risk of mortality and longer hospitalization.

The outcome of HIV-positive late presenters according to detectable CMV DNA and anti-CMV treatment

BACKGROUND

HIV late presenters are at high risk of cytomegalovirus (CMV) reactivation and end-organ disease. CMV viraemia has been associated with poor survival but the effect of anti-CMV treatment has not been studied in this setting.

METHODS

HIV-positive patients were included in a retrospective study if presenting with <350 CD4⁺ T-cells/μl and starting an antiretroviral treatment within 3 months of the diagnosis. Primary end point was 5-year survival according to the presence of CMV viraemia, CMV end-organ disease and anti-CMV treatment.

RESULTS

302 patients were included. 157 patients (52%) presented CMV viraemia (CMV-V) and 44 (14.6%) CMV end-organ disease (CMV-EOD). 5-year mortality was higher in CMV-EOD and CMV-V patients than in CMV-negative patients (11.4 versus 9.6 versus 0%; P=0.002). In patients with CMV-V, 5-year mortality was numerically higher in untreated patients (12.9% versus 6.9%; P=0.257) without reaching statistical significance. At univariate analysis the diagnosis of serious opportunistic infections (cryptococcosis, progressive multifocal leukoencephalopathy, lymphoma; P=0.001) and the absence of a negative CMV DNA in the follow-up (P<0.001) were associated with poor outcome. At multivariate analysis HCV coinfection (P=0.016; aOR 6.98, 95% CI 1.50, 32.59), the absence of a negative CMV DNA in the follow-up (P<0.001; aOR 19.40, 95% CI 3.70, 101.64) and marginally the absence of anti-CMV treatment (P=0.052; aOR 4.944, 95% CI 0.99, 24.73) were independent predictors of poor outcome.

CONCLUSIONS

CMV reactivation in HIV-positive patients with poor immunity is associated with worse prognosis: the pre-emptive use of anti-CMV therapy was associated with a better outcome in patients with CMV-V.

Expanding Patient Access to Investigational New Drugs: Overview of Intermediate and Widespread Treatment Investigational New Drugs, and Emergency Authorization in Public Health Emergencies

Individual patients with life-threatening or severely debilitating diseases can petition the U.S. Food and Drug Administration (FDA) through their physicians to have expanded access (EA) to drugs that are in clinical trials but have not reached full FDA approval (the "single-patient" investigational new drug [IND] application). Additionally, recent state and federal laws-so-called "right to try legislation"-allow patients to approach drug companies directly for access prior to FDA approval. While these pathways provide potential access for individual patients to investigational drugs, different EA pathways permit entire groups of certain patients to access investigational drugs prior to FDA approval. This review focuses on special categories of EA INDs intended for multiple patients-the intermediate-group IND and the widespread-treatment IND-as well as emergency authorization for use of investigational drugs and biological products (e.g., vaccines) in public health emergencies.

How to construct an optimal interim report: What the data monitoring committee does and doesn’t need to know

Background:

Data monitoring committees for randomized clinical trials have the responsibility of safeguarding interests of trial participants. To do so, the data monitoring committee must receive reports on safety and efficacy to assess risk/benefit and on trial conduct to ensure that the study can achieve its goals. This article outlines the key components of reports to the data monitoring committee and the important role of the unblinded statistician in preparing those reports.

Methods:

Most data monitoring committee meetings include open and closed sessions. For each session, there is a report of interim results. The open session is attended by the sponsor and lead investigators, including the statistician(s) responsible for the trial design. These investigators are blinded to the interim treatment comparisons. The closed session is attended by the data monitoring committee members and by the statistician(s) who prepared the closed report. These individuals are unblinded to interim treatment comparisons and therefore are not involved in study design changes. The optimal content of data monitoring committee reports and qualifications of the unblinded statistician(s) are discussed.

Reports:

Open reports should include responses to data monitoring committee recommendations, a synopsis of the protocol, a review of the protocol history and amendments, and information on enrollment, baseline characteristics, completeness of follow-up, and data quality. The open report is also a vehicle through which the sponsor and investigators should inform the data monitoring committee of relevant external information. Data in the open report are pooled over the treatment groups. The open report should not include data summaries by treatment group. The closed report should include a written summary with references to key tables and figures and methods used to prepare them. Tables and figures should summarize baseline characteristics, follow-up completeness, treatment adherence, and major safety and efficacy outcomes by treatment group. Text summaries should accompany the tables and figures. The data monitoring committee monitoring history (e.g. treatment differences at previous meetings) should be summarized. The unblinded statistician preparing the closed report should be familiar with the protocol and data collection plan and be capable of customizing the report to the current stage of the trial. This includes anticipating questions that may arise during the data monitoring committee review and pro-actively including data summaries to address these questions.

Conclusions:

There is considerable variation in the quality of open and closed data monitoring committee reports. Open and closed data monitoring committee reports should be concise, up to date, and informative. To achieve this, unblinded statisticians responsible for preparing closed data monitoring committee reports should be familiar with the statistical methods, the trial protocol, and the data collection plan. They should be capable of anticipating questions from the data monitoring committee and responding to requests for additional analyses.

Cytomegalovirus Retinitis in Pediatric Stem Cell Transplants: Report of a Recent Cluster and the Development of a Screening Protocol

PURPOSE

The incidence of cytomegalovirus (CMV) retinitis in the pediatric allogeneic hematopoietic stem cell transplant (HSCT) population is unknown. We report a cluster of 5 pediatric patients with CMV retinitis diagnosed in a 12-month period and compare this to the rate of CMV viremia and retinitis in the 4 years prior. Presented is the ophthalmic screening protocol developed in response to this experience.

DESIGN

Retrospective cross-sectional study.

METHODS

A retrospective chart review was performed on patients at Children's Hospital of Colorado (CHCO) who received allogeneic HSCT between January 2010 and December 2014. Fisher exact test was used to compare the proportion of CMV viremia and CMV retinitis in patients transplanted between January 2010 and December 2013 with those transplanted in 2014.

RESULTS

A total of 101 patients underwent allogeneic HSCT from January 2010 to December 2013; 32 (32%) tested positive for CMV viremia. No cases of CMV retinitis were identified. From January 2014 to December 2014, 28 patients underwent allogeneic HSCT; 13 patients (46%) had CMV viremia, not a statistically significant increase (P = .18). There were 5 cases of CMV retinitis diagnosed in those transplanted in 2014, a statistically significant increase compared with those transplanted in 2010-2013 (P = .0004). A multidisciplinary team was formed to review the literature and an ophthalmic screening protocol was developed.

CONCLUSION

Our recent cluster of CMV retinitis in pediatric allogeneic HSCT patients may suggest a rise in incidence of CMV retinitis. We propose an ophthalmic screening protocol to diagnose retinitis in pediatric HSCT patients in the early, often asymptomatic stage.

The 2015 Clinical Guidelines for the Treatment and Prevention of Opportunistic Infections in HIV-Infected Koreans: Guidelines for Opportunistic Infections

The Committee for Clinical Guidelines for the Treatment and Prevention of Opportunistic Infections of the Korean Society for AIDS was founded in 2011. The first edition of the Korean guidelines was published in 2012. The guideline recommendations contain important information for physicians working with human immunodeficiency virus (HIV)/acquired immune deficiency syndrome (AIDS) in the clinical field. It has become necessary to revise the guidelines due to new data in this field. These guidelines aim to provide up-to-date, comprehensive information regarding the treatment and prevention of opportunistic infections in HIV-infected Koreans. These guidelines deal with several common opportunistic infections, including pneumocystis pneumonia, tuberculosis, cryptococcal meningitis, etc. A brief summary of the revised guidelines is provided below. Recommendations are rated using the same system used in the previous guidelines.

Cytomegalovirus-associated ulceration of gastric conduit after chemoradiotherapy following esophagectomy for cancer

A 64-year-old man underwent radical esophagectomy for cancer and simultaneous reconstruction using the gastric conduit through the posterior mediastinum. Two courses of adjuvant chemotherapy were performed. Twenty-eight months postoperatively, recurrence of the cancer was detected in the mediastinal lymph nodes, and he underwent concurrent chemoradiotherapy and boost chemotherapy. Endoscopy was then performed to investigate the cause of epigastralgia, and multiple ulcerations were found in the lesser curvature of the gastric conduit. Although a proton-pump inhibitor was orally administered, the ulceration was intractable. Re-examination of the original biopsy specimens and serological testing revealed positivity for cytomegalovirus. The ulcers began to heal after administration of foscarnet sodium. After the treatment, no signs of exacerbation associated with reinstitution of chemotherapy were observed.

KSHV targeted therapy: an update on inhibitors of viral lytic replication

Kaposi’s sarcoma-associated herpesvirus (KSHV) is the causative agent of Kaposi’s sarcoma, primary effusion lymphoma and multicentric Castleman’s disease. Since the discovery of KSHV 20 years ago, there is still no standard treatment and the management of virus-associated malignancies remains toxic and incompletely efficacious. As the majority of tumor cells are latently infected with KSHV, currently marketed antivirals that target the virus lytic cycle have shown inconsistent results in clinic. Nevertheless, lytic replication plays a major role in disease progression and virus dissemination. Case reports and retrospective studies have pointed out the benefit of antiviral therapy in the treatment and prevention of KSHV-associated diseases. As a consequence, potent and selective antivirals are needed. This review focuses on the anti-KSHV activity, mode of action and current status of antiviral drugs targeting KSHV lytic cycle. Among these drugs, different subclasses of viral DNA polymerase inhibitors and compounds that do not target the viral DNA polymerase are being discussed. We also cover molecules that target cellular kinases, as well as the potential of new drug targets and animal models for antiviral testing.

Community-onset febrile illness in HIV-infected adults: variable pathogens in terms of CD4 counts and transmission routes

OBJECTIVES

The objective of the study is to investigate the causes of febrile illness among HIV-infected adults visiting the emergency department (ED) of a designated hospital for HIV care in Taiwan, an area of a low HIV prevalence.

METHODS

From January 2004 to December 2012, all febrile HIV-infected adults visiting the ED were retrospectively investigated. Recent CD4 lymphocyte counts near ED visits and HIV transmission route were designated as major predictors for the analyses. All variables and clinical information were derived from chart records.

RESULTS

Of the 196 eligible HIV-infected adults, major causes of febrile illness were lower respiratory tract infections (68, 34.7%), skin and soft tissue infections (31, 15.8%), intra-abdominal infections (22, 11.2%), and urinary tract infections (11, 5.6%). There were 150 pathogens identified. Staphylococcus aureus (51, 34.0%) and Pneumocystis jirovecii (26, 17.3%) were the major pathogens. In a multivariate analysis, injection drug use (odds ratio, 15.18; P < .001) and skin and soft tissue infections (odds ratio, 18.45; P = .001) were independently associated with S aureus infections, and the proportion of S aureus increased steadily with CD4 lymphocyte count (γ = 0.99; P = .01). Of pneumonic patients with recognized pathogens, P. jirovecii pneumonia was frequently associated with patients having a CD4 lymphocyte count of less than 100 cells/mm(3) (25/25, 100% vs 16/30, 53.3%; P < .001).

CONCLUSIONS

The causes of febrile illness in HIV-infected adults visiting the ED varied according to CD4 count and transmission route. Two independent risk factors, intravenous drug use and skin and soft tissue infections, were associated with S aureus infections. For HIV-infected adults with lower respiratory tract infections, a CD4 lymphocyte count of less than 100 cells/mm(3) was a risk factor for P. jirovecii pneumonia.

Assessment of the efficacy and safety of pre-emptive anti-cytomegalovirus (CMV) therapy in HIV-infected patients with CMV viraemia

A number of studies have demonstrated that cytomegalovirus (CMV) viraemia is a strong predictor for CMV end-organ disease (EOD) and death in HIV-infected patients. We assess the efficacy and safety of pre-emptive anti-CMV therapy (PACT) for preventing these events. We performed a retrospective study of all HIV-infected patients seen in our institution who had detectable CMV viraemia in 2007. Seventy-one patients with advanced HIV disease (median CD4 cell count = 61 cells/mm3) were studied. Sixteen patients received PACT (mainly valganciclovir). Patients who received PACT had lower CD4 cell counts and higher blood CMV DNA levels. The cumulative incidence of CMV EOD and death at one year was 44% and 21% in patients with and without PACT, respectively ( p = 0.013). Both PACT and high blood CMV DNA levels were significantly associated with CMV EOD and death in unadjusted analysis. In adjusted analyses, only blood CMV DNA levels remained significantly associated with the risk of CMV EOD and death, whereas PACT was associated with a non-significant trend towards reduced CMV EOD or death (hazard ratio: 0.25, p = 0.13). Five patients with PACT experienced severe drug-related adverse events. In conclusion, the use of PACT in HIV-infected patients with CMV viraemia could improve outcome but is associated with significant toxicity.

Cytomegalovirus viral load kinetics in patients with HIV/AIDS admitted to a medical intensive care unit: a case for pre-emptive therapy

Background

Cytomegalovirus (CMV) infection is associated with severe diseases in immunosuppressed patients; however, there is a lack of data for pre-emptive therapy in patients with HIV/AIDS.

Method

This was a retrospective study, which enrolled patients diagnosed with HIV/AIDS (CD4<200 cells/μl), who had detectable CMV viral load (VL) during their stay in an adult medical intensive care unit between 2009–2012.

Results

After screening 82 patients’ records, 41 patients met the enrolment criteria. Their median age was 37 (interquartile range [IQR]: 31–46), and median CD4 count was 29 cells/μl (IQR: 5–55). Sixteen patients (39%) had serial measurements of CMV VL before treatment with ganciclovir. Patients whose baseline CMV VL values were between 1,000–3,000 copies/ml had significantly higher values (median of 14,650 copies/ml) on follow-up testing done 4–12 days later. Those with undetectable VLs at baseline testing had detectable VLs (median of 1,590 copies/ml) mostly within 20 days of follow-up testing. Patients who had VLs >1,000 copies/ml at baseline testing had significantly higher mortality compared to those who had <1,000 copies/ml {hazard ratio of 3.46, p = 0.003 [95% confidence interval (CI): 1.55–7.71]}. Analysis of the highest CMV VL per patient showed that patients who had VLs of >5,100 copies/ml and did not receive ganciclovir had 100% mortality compared to 58% mortality in those who received ganciclovir at VLs of >5,100 copies/ml, 50% mortality in those who were not treated and had low VLs of <5,100 copies/ml, and 44% mortality in those who had ganciclovir treatment at VLs of <5,100 copies/ml (p = 0.084, 0.046, 0.037, respectively).

Conclusion

This study showed a significantly increased mortality in patients with HIV/AIDS who had high CMV VLs, and suggests that a threshold value of 1,000 copies/ml may be appropriate for pre-emptive treatment in this group.

Valganciclovir for the prevention and treatment of cytomegalovirus disease in immunocompromised hosts

Valganciclovir (Valcyte, Roche), a prodrug of the deoxyguanosine analog ganciclovir (Cytovene, Roche), is indicated for induction and maintenance treatment of cytomegalovirus retinitis in patients with AIDS and for prevention of cytomegalovirus disease in selected high-risk solid organ transplant recipients. After oral administration, valganciclovir is rapidly absorbed and converted to ganciclovir by intestinal and hepatic esterases. Valganciclovir is a highly recognized substrate of the intestinal peptide transporter PEPT1, which underlies the tenfold higher bioavailability of ganciclovir after valganciclovir compared to oral ganciclovir administration. At oral dose of 900 mg, valganciclovir provides a systemic ganciclovir exposure that is comparable to intravenous ganciclovir, at the standard dose of 5 mg/kg of body weight. Subsequent phosphorylation of ganciclovir, which occurs preferentially within cytomegalovirus-infected cells, results in the active metabolite, ganciclovir triphosphate, which is responsible for suppressing viral DNA synthesis by competitively inhibiting the incorporation of the natural substrate deoxyguanosine into viral DNA and thereby, terminating cytomegalovirus replication.

Prevention of HIV-associated opportunistic infections and diseases in the age of highly active antiretroviral therapy

Since the introduction of highly active antiretroviral therapy (HAART), the rates of opportunistic infections have decreased markedly as has overall morbidity and mortality from HIV infection in developed countries. However, opportunistic infections remain the most important cause of death in HIV-infected people due to both late presentation of HIV infections and failure of HAART to adequately restore cell-mediated immunity in all individuals. While prophylaxis may be discontinued in patients who have responded to HAART with sustained increases of their CD4 counts above risk thresholds, for those patients who fail HAART, those who are unable to tolerate it, or whose treatments are interrupted, opportunistic-infection prophylaxis remains essential. Some HIV-associated diseases, such as anogenital human papilloma virus-induced neoplasia and hepatitis C infection, have not decreased in frequency with the advent of HAART. For these conditions, effective screening and treatment programs will be necessary to prevent ongoing morbidity. This review will provide an update on HIV-associated opportunistic infections and their prevention in the age of HAART, as well as discuss novel presentations of opportunistic illnesses, such as immune restoration syndromes.

Burden of HIV-related cytomegalovirus retinitis in resource-limited settings: a systematic review

BACKGROUND

Cytomegalovirus (CMV) is a late-stage opportunistic infection in people living with human immunodeficiency virus (HIV)/AIDS. Lack of ophthalmological diagnostic skills, lack of convenient CMV treatment, and increasing access to antiretroviral therapy have all contributed to an assumption that CMV retinitis is no longer a concern in low- and middle-income settings.

METHODS

We conducted a systematic review and meta-analysis of published and unpublished studies reporting prevalence of CMV retinitis in low- and middle-income countries. Eligible studies assessed the occurrence of CMV retinitis by funduscopic examination within a cohort of at least 10 HIV-positive adult patients.

RESULTS

We identified 65 studies from 24 countries, mainly in Asia (39 studies, 12 931 patients) and Africa (18 studies, 4325 patients). By region, the highest prevalence was observed in Asia with a pooled prevalence of 14.0% (11.8%-16.2%). Almost a third (31.6%, 95% confidence interval [CI], 27.6%-35.8%) had vision loss in 1 or both eyes. Few studies reported immune status, but where reported CD4 count at diagnosis of CMV retinitis was <50 cells/µL in 73.4% of cases. There was no clear pattern of prevalence over time, which was similar for the period 1993-2002 (11.8%; 95% CI, 8%-15.7%) and 2009-2013 (17.6%; 95% CI, 12.6%-22.7%).

CONCLUSIONS

Prevalence of CMV retinitis in resource low- and middle-income countries, notably Asian countries, remains high, and routine retinal screening of late presenting HIV-positive patients should be considered. HIV programs must ensure capacity to manage the needs of patients who present late for care.

Preemptive therapy prevents cytomegalovirus end-organ disease in treatment-naïve patients with advanced HIV-1 infection in the HAART era

BACKGROUND

The efficacy of preemptive therapy against cytomegalovirus (CMV) infection remains unknown in treatment-naïve patients with advanced HIV-1 infection in the HAART era.

METHODS

The subjects of this single-center observation study were 126 treatment-naïve HIV-1 infected patients with positive CMV viremia between January 1, 2000 and December 31, 2006. Inclusion criteria were age more than 17 years, CD4 count less than 100/μl, plasma CMV DNA positive, never having received antiretroviral therapy (ART) and no CMV end-organ disease (EOD) at first visit. The incidence of CMV-EOD was compared in patients with and without preemptive therapy against CMV-EOD. The effects of the CMV preemptive therapy were estimated in uni- and multivariate Cox hazards models.

RESULTS

CMV-EOD was diagnosed in 30 of the 96 patients of the non-preemptive therapy group (31%, 230.3 per 1000 person-years), compared with 3 of the 30 patients of the preemptive therapy group (10%, 60.9 per 1000 person-years). Univariate (HR = 0.286; 95%CI, 0.087-0.939; p = 0.039) and multivariate (adjusted HR = 0.170; 95%CI, 0.049-0.602; p = 0.005) analyses confirmed that CMV-EOD is significantly prevented by CMV preemptive therapy. Multivariate analysis showed that plasma CMV DNA level correlated significantly with CMV-EOD (per log10/ml, adjusted HR = 1.941; 95%CI, 1.266-2.975; p = 0.002). Among the 30 patients on preemptive therapy, 7 (23.3%) developed grade 3-4 leukopenia. The mortality rate was not significantly different between the two groups (p = 0.193, Log-rank test).

CONCLUSIONS

The results indicate that preemptive therapy lowers the incidence of CMV-EOD by almost 25%. Preemptive therapy for treatment-naïve patients with CMV viremia is effective, although monitoring of potential treatment-related side effects is required.

Central Nervous System Infections

Central nervous system (CNS) infections—i.e., infections involving the brain (cerebrum and cerebellum), spinal cord, optic nerves, and their covering membranes—are medical emergencies that are associated with substantial morbidity, mortality, or long-term sequelae that may have catastrophic implications for the quality of life of affected individuals. Acute CNS infections that warrant neurointensive care (ICU) admission fall broadly into three categories—meningitis, encephalitis, and abscesses—and generally result from blood-borne spread of the respective microorganisms. Other causes of CNS infections include head trauma resulting in fractures at the base of the skull or the cribriform plate that can lead to an opening between the CNS and the sinuses, mastoid, the middle ear, or the nasopharynx. Extrinsic contamination of the CNS can occur intraoperatively during neurosurgical procedures. Also, implanted medical devices or adjunct hardware (e.g., shunts, ventriculostomies, or external drainage tubes) and congenital malformations (e.g., spina bifida or sinus tracts) can become colonized and serve as sources or foci of infection. Viruses, such as rabies, herpes simplex virus, or polioviruses, can spread to the CNS via intraneural pathways resulting in encephalitis. If infection occurs at sites (e.g., middle ear or mastoid) contiguous with the CNS, infection may spread directly into the CNS causing brain abscesses; alternatively, the organism may reach the CNS indirectly via venous drainage or the sheaths of cranial and spinal nerves. Abscesses also may become localized in the subdural or epidural spaces. Meningitis results if bacteria spread directly from an abscess to the subarachnoid space. CNS abscesses may be a result of pyogenic meningitis or from septic emboli associated with endocarditis, lung abscess, or other serious purulent infections. Breaches of the blood–brain barrier (BBB) can result in CNS infections. Causes of such breaches include damage (e.g., microhemorrhage or necrosis of surrounding tissue) to the BBB; mechanical obstruction of microvessels by parasitized red blood cells, leukocytes, or platelets; overproduction of cytokines that degrade tight junction proteins; or microbe-specific interactions with the BBB that facilitate transcellular passage of the microorganism. The microorganisms that cause CNS infections include a wide range of bacteria, mycobacteria, yeasts, fungi, viruses, spirochaetes (e.g., neurosyphilis), and parasites (e.g., cerebral malaria and strongyloidiasis). The clinical picture of the various infections can be nonspecific or characterized by distinct, recognizable clinical syndromes. At some juncture, individuals with severe acute CNS infections require critical care management that warrants neuro-ICU admission. The implications for CNS infections are serious and complex and include the increased human and material resources necessary to manage very sick patients, the difficulties in triaging patients with vague or mild symptoms, and ascertaining the precise cause and degree of CNS involvement at the time of admission to the neuro-ICU. This chapter addresses a wide range of severe CNS infections that are better managed in the neuro-ICU. Topics covered include the medical epidemiology of the respective CNS infection; discussions of the relevant neuroanatomy and blood supply (essential for understanding the pathogenesis of CNS infections) and pathophysiology; symptoms and signs; diagnostic procedures, including essential neuroimaging studies; therapeutic options, including empirical therapy where indicated; and the perennial issue of the utility and effectiveness of steroid therapy for certain CNS infections. Finally, therapeutic options and alternatives are discussed, including the choices of antimicrobial agents best able to cross the BBB, supportive therapy, and prognosis.

Cytomegalovirus retinitis treated with valganciclovir in Wegener's granulomatosis

A case of cytomegalovirus (CMV) retinitis in a patient with Wegener’s granulomatosis treated with oral valganciclovir as maintenance therapy is reported. A 68-year-old male patient with anti-proteinase-3 ANCA-positive Wegener’s granulomatosis who was receiving immunosuppressive therapy with methylprednisolone, cyclophosphamide, and azathioprine developed CMV retinitis. The patient received intravenous ganciclovir as induction therapy and oral valganciclovir as maintenance therapy. The patient responded to treatment and showed no recurrence for 8 months. There were no serious adverse effects associated with oral valganciclovir. Oral valganciclovir is convenient and effective for the management of CMV retinitis in the patient with Wegener’s granulomatosis.

Cytomegalovirus infection causes morbidity and mortality in patients with autoimmune diseases, particularly systemic lupus: in a Chinese population in Taiwan

To investigate the clinical outcome of cytomegalovirus (CMV) infection in febrile hospitalized patients with autoimmune diseases, mostly systemic lupus erythematosus (SLE). Fifty-four febrile patients were analyzed retrospectively. Half were diagnosed as CMV infection, by positive CMV pp65 antigenemia assay. Clinical and laboratory data between two groups were compared. Correlation between laboratory data and SELENA-SLEDAI scores/mortality were analyzed in the CMV infection group. Receiver operating characteristic analysis was performed to determine the cutoff points of different parameters for predicting mortality or morbidity. The CMV infection group received a higher corticosteroid dosage (mean 26.3 mg/day) and a higher percentage of azathioprine use before admission than the non-CMV infection group. In the former, the deceased subgroup had a significantly higher number of infected leukocytes for CMV (shortened as CMV counts, P = 0.013), more cases of bacterial infection (P = 0.090), and a higher SLE disease activity index score (P = 0.072) than the alive subgroup. The CMV infection group had lower lymphocyte count and more positive bacterial infection than the non-CMV infection group did (P = 0.013 and P = 0.027, respectively). A level of 25 CMV particles/5 × 10(5) polymorphonuclear neutrophils (PMN) was the best cutoff point for predicting CMV-associated mortality, with a sensitivity of 75.0% and specificity of 72.2%. Moderate dose (30 mg/day) of prednisolone or azathioprine use predisposes patients with autoimmune diseases to CMV infection with concurrent bacterial infection. In particular, peak CMV counts at 25/5 × 10(5) PMN or low lymphocyte counts predict mortality or morbidity, respectively.

Human herpesvirus 8-associated neoplasms: the roles of viral replication and antiviral treatment

PURPOSE OF REVIEW

In this review, we highlight the importance of human herpesvirus 8 (HHV-8) lytic replication and the potential for antiviral therapies to prevent or treat HHV-8-related neoplasms.

RECENT FINDINGS

Diseases caused by HHV-8 infection include Kaposi sarcoma, multicentric Castleman disease (MCD), and primary effusion lymphoma (PEL), which occur primarily in patients with HIV infection. Kaposi sarcoma is the most common AIDS-associated malignancy worldwide. MCD and PEL occur less commonly but, like Kaposi sarcoma, are associated with poor treatment outcomes. Like all herpesviruses, HHV-8 is capable of either latent or lytic infection of cells. Although HHV-8 infection of tumor cells is predominately latent, accumulating data point to the importance of both lytic phase viral gene products and production of infectious virus. Antiviral agents that target herpesvirus DNA synthesis, such as ganciclovir, inhibit HHV-8 lytic replication and can prevent Kaposi sarcoma. Several HIV protease inhibitors may interfere with tumor growth and angiogenesis, and one protease inhibitor, nelfinavir, directly inhibits HHV-8 replication in vitro.

SUMMARY

Controlled trials are indicated to determine the clinical utility of antiviral suppression of HHV-8 replication, and identify the optimal antiretroviral regimens, for the prevention and treatment of Kaposi sarcoma.

Clinical relevance of cytomegalovirus viraemia(*,†)

BACKGROUND

Using new sensitive quantitative polymerase chain reaction (PCR) assays, cytomegalovirus (CMV) DNA is often detectable in the plasma of immunosuppressed patients. We investigated the prognostic value of a positive CMV DNA test for the development of CMV end-organ disease, other AIDS-defining events and mortality.

METHODS

A survival analysis was performed, using the Kaplan-Meier method and Cox proportional hazards models, for patients prospectively followed in the Swiss HIV Cohort Study, from January 1996 to December 2007, who were CMV-seropositive, had a CD4 count of ≤ 100 cells/μL, and had a plasma sample available for the measurement of baseline CMV DNA with an ultrasensitive PCR. The outcome analysed was an AIDS-defining event, including CMV end-organ disease, or death. Variables analysed at the time of CMV measurement were demographic variables, CD4 cell counts, HIV-1 RNA loads, and use and type of highly active antiretroviral therapy (HAART).

RESULTS

Of 1128 patients, 208 (18%) presented an AIDS-defining event and 246 (22%) died. A total of 368 patients (34% of samples) had detectable CMV DNA at baseline, with DNA concentrations of up to 38 800 copies/mL. In the multivariate analysis, CMV DNA predicted evolution not only towards CMV end-organ disease [hazard ratio (HR) 12.6; 95% confidence interval (CI) 4.27-37.41], but also towards other AIDS-defining events (HR 2.6; 95% CI 1.60-4.33) and death (HR 1.9; 95% CI 1.10-3.34).

CONCLUSION

Quantitative CMV DNA detected in the plasma of HIV-infected patients with CD4 counts ≤ 100 cells/μL is a predictor for HIV disease progression, CMV disease and death. A single low value of 80 copies/mL identifies patients at low but significantly increased risk during the following months, after the measurement.

Immune-based therapies for cytomegalovirus infection

Immune fitness is critical in the pathogenesis and outcome of cytomegalovirus (CMV) infection. CMV disease is seen almost exclusively among individuals with an immature or defective immune system, such as patients with AIDS, transplant recipients and the developing fetus. These observations have generated interest in immune-based strategies for the management of CMV disease. Among the immune-based therapies that have been investigated in experimental and clinical settings are: passive immunotherapy with immunoglobulin; CMV vaccination; adoptive CMV-specific T-cell immunotherapy; and immune reconstitution strategies (HAART in AIDS patients, and a reduction in pharmacologic immunosuppression among transplant recipients). However, except for immune reconstitution strategies, there is no widely accepted immune-based strategy that is proven to be highly effective for CMV disease management. The benefits of immunoglobulins remain debated in an era when antiviral therapy is widely available. CMV vaccination and adoptive immunotherapy, on the other hand, remain experimental, but have had encouraging preliminary results.

Detection of opportunistic DNA viral infections by multiplex PCR among HIV infected individuals receiving care at a tertiary care hospital in South India

PURPOSE

Opportunistic viral infections cause increased morbidity and mortality among human immunodeficiency virus (HIV) infected individuals, especially those who are not on antiretroviral treatment. Early diagnosis of these opportunistic viruses will be able to reduce the risk of disease progression with appropriate intervention.

MATERIALS AND METHODS

Multiplex PCR was attempted to detect the opportunistic herpes viruses (HSV-1, HSV-2, VZV, EBV, and CMV), adenovirus and polyoma viruses (JC and BK) in three cocktails of PCR reactions. Subsequently, all the viruses detected were quantitated by testing using monoplex real time PCR. Whole blood samples collected between 2006 and 2007 from 68 treatment naïve HIV-1 infected and 30 normal healthy individuals were tested for these eight viruses. Among the 68 HIV-1 infected individuals 35 had CD4+ T cell count less than or equal to 200 while the other 33 had greater than 200 CD4+ T cells.

RESULTS

Among the 68 HIV-1 infected individuals, 49 (72%) were positive for EBV, 5 (7%) samples were positive for CMV. All the five CMV positive individuals had CD4+ T cell count of less than or equal to 200 cells/microL. The mean EBV load among the individuals with a CD4+ T cells of less than or equal to 200 cells/microL was 3.88 log(10) while among those with greater than 200 CD4+ T cells it was 3.75 log(10) . The mean CMV load was 6.98 log(10). Three samples were positive for both CMV & EBV. None of the samples was positive for HSV-1, HSV-2, VZV, Adenovirus, JC and BK viruses.

CONCLUSIONS

In our study, multiplex PCR based detection system was found useful in detecting opportunistic viruses in HIV infected individuals. Though EBV is the most prevalent opportunistic viral infection among HIV infected individuals, there was no significant association between EBV load, CD4+ T cell counts and HIV-1 virus load. CMV was seen in HIV infected individuals with low CD4+ T cell counts (less than 200 cells/microL).

Short synthesis and antiviral activity of acyclic phosphonic acid nucleoside analogues

An efficient route for synthesizing novel allylic and cyclopropanoid phosphonic acid nucleoside analogues is described. The condensation of the bromine derivatives 6 and 18 with nucleoside bases (A, U, T, C, G) under standard nucleophilic substitution and deprotection conditions, afforded the target phosphonic acid nucleoside analogues. These compounds were evaluated for their antiviral properties against various viruses. Cyclopropanoid phosphonic adenine nucleoside analogue 23 showed significant anti-HIV activity.

Maintaining confidentiality of interim data to enhance trial integrity and credibility

BACKGROUND

For clinical trials of interventions that could affect mortality or major morbidity, Data Monitoring Committees have an important role in safeguarding patient interests and enhancing trial integrity and credibility. In trials overseen by an independent DMC it is widely recognized that interim data should remain confidential to the DMC and to the statistical group preparing reports. However, we have found that the principle of confidentiality is not always followed in practice, particularly where the interim data include complete results on a short-term outcome measure.

PURPOSE

To discuss the reasoning and evidence supporting the principle of confidentiality of interim data with emphasis on the setting where the interim data include complete results on a short-term outcome.

METHODS

We review the reasons why wider access to interim data can increase the risk of false positive or false negative conclusions and discuss the types of harm which can occur. We provide illustrations and insights from recent experiences and discuss the level of consensus in the research community.

RESULTS

The arguments in favor of early release of interim data include the need to provide reliable data in a timely manner to patients and physicians, the potential to increase the enthusiasm of trial investigators, and to restore equipoise. However interim data, even where these include complete results on a short-term outcome measure, provide an unreliable and biased assessment of the overall benefit-to-risk profile of the trial treatments. Pre-judgment based on over-interpretation of such interim data can affect recruitment, treatment delivery, and follow-up, risking the ability of the trial to achieve its goals.

CONCLUSIONS

In order to preserve the integrity of a trial and safeguard the interests of patients, interim data, including complete data on short-term outcomes, should remain confidential to the DMC and the statistical group responsible for preparing interim reports until the trial has achieved its primary objectives.

Antiviral Chemistry & Chemotherapy's Current Antiviral Agents FactFile (2nd Edition): DNA Viruses

Although most of the recent attempts to develop new antiviral agents have been focussed on RNA viruses (in particular, HIV and hepatitis C virus), a few new compounds are now awaiting their entry into the field of DNA viruses, particularly poxviruses, such as variola virus, because of the bioterrorist context, and herpesviruses, such as herpes simplex virus and cytomegalovirus, where the market scene has for many years been dominated by acyclovir, penciclovir and ganciclovir and their respective orally bioavailable prodrugs: valaciclovir, famciclovir and valganciclovir. Here, we review the current ‘state of the art’ with old compounds ready to rotate off and new compounds eagerly awaiting to appear on the continuously evolving scene of antiviral drug development.

Synthesis of enantiopure pseudo-L-vinylcyclopropyl nucleosides bearing quaternary carbon as potential anti-herpesvirus agent

Pseudo-L-vinylcyclopropyl adenine and guanine nucleosides 11 and 12 were designed and enantiopurely synthesized starting from (S)-epichlorohydrin using tandem alkylation, regioselective oxirane-ring opening, and chemoselective reduction as key steps.

Asymmetric synthesis of novel pseudo-D-vinylcyclopropyl nucleosides bearing quaternary carbon as potential anti-herpesvirus agent

Pseudo-D-vinylcyclopropyl nucleosides 10-12 bearing a quaternary carbon were designed and synthesized starting from (R)-epichlorohydrin using a tandem reaction of double alkylation and lactonization via oxirane-ring opening reaction, a Wittig reaction, and chemoselective reduction as potential anti-herpesvirus agent.

Characteristics of untreated AIDS-related cytomegalovirus retinitis. I. Findings before the era of highly active antiretroviral therapy (1988 to 1994)

PURPOSE

To identify factors related to variations in the appearance of untreated AIDS-related cytomegalovirus (CMV) retinitis in severely immunodeficient individuals before the availability of highly active antiretroviral therapy (HAART) and to draw inferences regarding early events in the natural history of CMV retinitis based on clinical findings.

DESIGN

Retrospective, observational case series.

METHODS

We evaluated a series of 100 adult patients with AIDS and newly diagnosed CMV retinitis before the HAART era who were not being treated with specific anti-CMV therapy. Demographic factors, ophthalmic findings, and the influence of drug therapy (zidovudine, acyclovir) on lesion characteristics were evaluated. Lesion border opacity was scored using a four-point scale of severity.

RESULTS

Lesions could be categorized by type (fulminant/edematous or indolent/granular) in only 66% of eyes. Severe lesion border opacity (4+) was related to presence of zone 1 lesions (P = .032) and greater extent of disease (P = .004). Acyclovir use was associated with less severe opacity (P = .029) and less zone 1 involvement (P = .016). Early lesions were adjacent to vessels in 73% of eyes; the fovea was involved in 13% of eyes.

CONCLUSIONS

Lesion location and drug use that affects virus activity may influence the severity of lesion border opacity, a measure that may be more useful than lesion type in future clinical studies of CMV retinitis. In contrast to earlier concepts, CMV retinitis does not seem to be a fovea-sparing disease. Findings in this study can serve as a reference for investigations into possible changes in CMV retinitis since the introduction of HAART.

Dipeptide monoester ganciclovir prodrugs for transscleral drug delivery: targeting the oligopeptide transporter on rabbit retina

PURPOSE

The overall aim of this research work was to evaluate a series of dipeptide monoester prodrugs of an antiviral agent, ganciclovir (GCV), for oligopeptide transporter-targeted transscleral drug delivery to rabbit retina.

METHODS

The permeability and enzymatic hydrolysis of dipeptide monoester GCV prodrugs were evaluated using freshly excized rabbit retinal pigment epithelium (RPE)-choroidsclera (RCS) and sclera tissue preparations. Affinity and transport mechanism of these prodrugs and their translocation across RCS were investigated through competitive inhibition studies of [(3)H]glycylsarcosine with the prodrugs.

RESULTS

The transport of glycylsarcosine was found to be saturable (K(m) = 1.21 +/- 0.41 mM, V(max) = 15.89 +/- 1.54 pmoles/min/cm(2)), pH, temperature, and energy dependant. Dipeptides, angiotensin converting enzyme inhibitors, and a beta-lactum antibiotic strongly inhibited the transport of glycylsarcosine indicating the functional presence of oligopeptide transport (OPT) system on the RPE. Dipeptide prodrugs (valine-valine-GCV, glycine-valine-GCV, and tyrosine-valine-GCV), and valine-GCV demonstrate a high enzymatic stability and affinity toward the retinal OPT system. The transport of the prodrugs was significantly inhibited ( approximately 50%) in the presence of glycylsarcosine. The rank order of scleral permeability was Gly-Val-GCV approximately GCV>Val-GCV>Tyr-Val-GCV approximately Val-Val-GCV. The RCS permeability values of Val-GCV (3.29 +/- 0.09 x 10(6)cm/s), Val-Val-GCV (4.14 +/- 0.33 x 10(6)cm/s), Gly-Val-GCV (3.40 +/- 0.47 x 10(6)cm/s) and Tyr-Val-GCV (3.08 +/- 0.29 x 10(6)cm/s) were two-fold higher than that of GCV (1.61 +/- 0.06 x 10(6)cm/s).

CONCLUSIONS

The dipeptide monoester GCV prodrugs, owning to higher lipophilicity and OPT-mediated translocation across RPE, appear to be promising candidates in the treatment of ocular cytomegalovirus infections following an episcleral administration.

An unadjusted NNT was a moderately good predictor of health benefit

BACKGROUND AND OBJECTIVE

Whether the number needed to treat (NNT) is sufficiently precise to use in clinical practice remains unclear. We compared unadjusted NNTs to quality-adjusted life years (QALYs) gained, a more comprehensive measures of health benefit.

STUDY DESIGN AND SETTING

From a subset (n = 65) of a dataset of 228 cost-effectiveness analyses, we compared how well NNTs predicted clinically important QALY gains using correlation analysis, multivariable models and receiver-operator curve (ROC) analysis.

RESULTS

NNT was inversely correlated with QALY gains (P < .001); this relationship was affected by quality of life and life-expectancy gains of treatment (P <or= .04). The NNT is a moderately accurate predictor of treatments that provide large health benefits (area under ROC 0.74-0.81). For ruling out therapies with low QALY gains (threshold <or=0.125 to <or=0.5 QALYs), an NNT >15 had a sensitivity of 82% to 100%. For ruling in therapies with high QALY gains (threshold >or=0.125 to >or=0.5 QALYs), an NNT <or=5 had a specificity of 77%.

CONCLUSION

Using NNT thresholds of <or=5 and >15 to rule in and out therapies with large QALY gains may provide general guidance regarding the magnitude of health benefit.