The incidence of cytomegalovirus (CMV) antigenemia and CMV disease is reduced by highly active antiretroviral therapy

Development and Clinical Translation of Approved Gene Therapy Products for Genetic Disorders

The field of gene therapy is striving more than ever to define a path to the clinic and the market. Twenty gene therapy products have already been approved and over two thousand human gene therapy clinical trials have been reported worldwide. These advances raise great hope to treat devastating rare and inherited diseases as well as incurable illnesses. Understanding of the precise pathomechanisms of diseases as well as the development of efficient and specific gene targeting and delivery tools are revolutionizing the global market. Currently, human cancers and monogenic disorders are indications number one. The elevated prevalence of genetic disorders and cancers, clear gene manipulation guidelines and increasing financial support for gene therapy in clinical trials are major trends. Gene therapy is presently starting to become commercially profitable as a number of gene and cell-based gene therapy products have entered the market and the clinic. This article reviews the history and development of twenty approved human gene and cell-based gene therapy products that have been approved up-to-now in clinic and markets of mainly North America, Europe and Asia.

Ocular herpes: the pathophysiology, management and treatment of herpetic eye diseases

Herpesviruses are a prominent cause of human viral disease, second only to the cold and influenza viruses. Most herpesvirus infections are mild or asymptomatic. However, when the virus invades the eye, a number of pathologies can develop and its associated sequelae have become a considerable source of ocular morbidity. The most common culprits of herpetic eye disease are the herpes simplex virus (HSV), varicella zoster virus (VZV), and cytomegalovirus (CMV). While primary infection can produce ocular disease, the most destructive manifestations tend to arise from recurrent infection. These recurrent infections can wreck devastating effects and lead to irreversible vision loss accompanied by a decreased quality of life, increased healthcare usage, and significant cost burden. Unfortunately, no method currently exists to eradicate herpesviruses from the body after infection. Treatment and management of herpes-related eye conditions continue to revolve around antiviral drugs, although corticosteroids, interferons, and other newer therapies may also be appropriate depending on the disease presentation. Ultimately, the advent of effective vaccines will be crucial to preventing herpesvirus diseases altogether and cutting the incidence of ocular complications.

Risk of cataract among subjects with acquired immune deficiency syndrome free of ocular opportunistic infections

PURPOSE

To evaluate the risk of cataract in the setting of AIDS.

DESIGN

Prospective cohort study.

PARTICIPANTS

Subjects with AIDS free of ocular opportunistic infections throughout catamnesis.

METHODS

From 1998 through 2008, subjects 13 years of age or older were enrolled. Demographic characteristics and clinical characteristics were documented at enrollment and semiannually.

MAIN OUTCOME MEASURES

Cataract was defined as high-grade lens opacity observed by biomicroscopy judged to be the cause of a best-corrected visual acuity worse than 20/40. Eyes that underwent cataract surgery during follow-up were considered to have developed cataract before the first visit when pseudophakia or aphakia was observed.

RESULTS

Among 1606 participants (3212 eyes) at enrollment, 1.9% (95% confidence interval [CI]: 1.3%-2.7%) were observed to have cataract or prior cataract surgery. Among the 2812 eyes initially free of cataract and followed longitudinally (median follow-up, 4.6 years), the incidence of cataract was 0.37%/eye-year (95% CI: 0.26%-0.53%). In addition to age, significant cataract risk factors included prior cataract in the contralateral eye (adjusted hazard ratio [aHR], 21.6; 95% CI: 10.4-44.8), anterior segment inflammation (aHR, 4.40; 95% CI: 1.64-11.9), prior retinal detachment (aHR, 4.94; 95% CI: 2.21-11.0), and vitreous inflammation (aHR, 7.12; 95% CI: 2.02-25.0), each studied as a time-updated characteristic. Detectable human immunodeficiency virus RNA in peripheral blood was associated with lower risk of cataract at enrollment (adjusted odds ratio, 0.32; 95% CI: 0.12-0.80) but not of incident cataract (aHR, 1.58; 95% CI: 0.90-2.76). After adjustment for other factors, neither the then-current absolute CD4+ T-cell count nor antiretroviral therapy status showed consistent association with cataract risk, nor did an additive diagnosis of other comorbidities. Compared with the available population-based studies that used similar definitions of cataract, the age-specific prevalence of cataract in our cohort was higher than in 1 of 2 such studies, and the age-specific incidence of cataract surgery was higher.

CONCLUSIONS

Our results suggest cataract may occur earlier among patients with AIDS free of ocular opportunistic infections than in the general population. Cataract risk was associated most strongly with age and with other ocular morbidity in this population. With improved survival, the burden of cataract likely will increase for persons with the human immunodeficiency virus or AIDS.

Manipulation of dendritic cell functions by human cytomegalovirus

Dendritic cells are the most potent antigen-presenting cells of the mammalian immune system and are central to the initiation and maintenance of the adaptive immune response. They are crucial for the presentation of antigen to T cells and B cells, as well as the induction of chemokines and proinflammatory cytokines, which orchestrate the balance of the cell-mediated (Th1) and antibody (Th2) response. This ability of dendritic cells to present antigen and release chemokines and cytokines also bridges the innate and adaptive immune responses by driving T cell activation. These cells thus possess key immunological functions that make them the front line of defence for the targeting and clearance of any invading pathogen and, as such, they underpin the host immune response to infection. For efficient infection, invading pathogens often need to overcome these sentinel immune functions. It is therefore not surprising that pathogens have evolved numerous mechanisms to target dendritic cell functions directly or indirectly during infection, and at least one herpesvirus--human cytomegalovirus--has evolved a life cycle that hijacks dendritic cells for its long-term persistence in the infected host.

Risk of Immune Recovery Uveitis in Patients with AIDS and Cytomegalovirus Retinitis

OBJECTIVE

To evaluate the prevalence of and risk factors for immune recovery uveitis (IRU) in eyes of patients with AIDS and cytomegalovirus (CMV) retinitis.

DESIGN

Enrollment data from a 19-clinical center cohort study.

PARTICIPANTS

Three hundred seventy-four patients with AIDS and CMV retinitis affecting 539 eyes.

METHODS

Patients with AIDS were enrolled at 19 United States AIDS ophthalmology clinics. Data were collected by interview, review of medical records, ophthalmic examination, and phlebotomy.

MAIN OUTCOME MEASURE

Immune recovery uveitis.

RESULTS

Thirty-six patients (9.6%) were diagnosed with IRU involving 50 eyes. The CD4+ T-cell count of 31 of these had risen by > or =50 cells per microliter above nadir to a level > or = 100 cells per microliter (immune recovery), making up 17.6% of the patients known to have immune recovery after diagnosis of CMV retinitis (95% confidence interval, 12.3%-24.1%). No patients with IRU were observed to have active retinitis or detectable CMV DNA in peripheral blood (P<0.001 and P<0.001 with respect to patients without IRU). Other factors associated with IRU were > or =25% retinal area (odds ratio [OR], 2.72; P = 0.014) or posterior pole involvement with CMV retinitis (odds ratio, 0.43; P = 0.039), treatment with intravitreous injection of cidofovir (OR, 10.6 with respect to eyes never exposed to intravitreous or IV cidofovir; P<0.001), and male gender (OR, 0.26; P = 0.012). More eyes with IRU had visual acuity (VA) of 20/50 or worse (38.0% vs. 26.3%, P = 0.077) relative to eyes without IRU, but the proportions with VA of 20/200 or worse were similar (14.0% vs. 13.8%, P = 0.96). Eyes with IRU more commonly had cystoid macular edema (CME) (45.5% vs. 3.7%, P<0.001) and epiretinal membrane (48.9% vs. 13.3%, P<0.001) than eyes without IRU.

CONCLUSIONS

Among eyes of patients with immune recovery, the prevalence of IRU is substantial. Eyes with IRU have a high risk of additional morbidity over and above that seen with CMV retinitis, with several-fold higher risk of CME and epiretinal membrane. Large CMV lesions and use of intravitreous cidofovir are risk factors for IRU.

Retinal and extraocular cytomegalovirus end-organ disease in HIV-infected patients in Europe: a EuroSIDA study, 1994-2001

This multicentre prospective cohort study by the EuroSIDA study group was designed to determine the factors affecting the incidence of cytomegalovirus (CMV) end-organ disease (CMVD) and the rate of survival after diagnosis in patients with AIDS during the years 1994-2001. This period includes two eras, the pre-HAART era and the HAART era, because HAART affects the natural history of HIV infection, especially with respect to opportunistic infections, including CMV infection. Clinical and laboratory data were collected from the charts of 8,556 patients in 63 AIDS clinics in Europe. A total of 707 patients had CMVD at recruitment and at follow-up: 449 with retinitis (CMVR), 190 with extraocular CMV disease (EOCMVD), and 58 with both. Of the cases of EOCMVD, 66% involved the gastrointestinal tract and 17% the central nervous system. Of patients with a CD4+ count of < or =200 mm(-3) initially, 1.8% on HAART developed CMVD within a 24-month period, as compared to 11.1% on dual therapy and 14.3% without treatment (P<0.0001). There were highly significant differences in survival according to the calendar year (P<0.0001), with mortality declining from 79% during the years 1994-1995 to 42% in 2000-2001. The incidence of death after any CMVD was 28.4 per 100 patient-years of follow-up. Median survival of CMVR patients and EOCMVD patients was 11 and 7 months, respectively, the prognosis being better among patients with gastrointestinal rather than neurological CMVD. The initiation of HAART was associated with a 37% decrease in mortality (P<0.05). Eighteen percent of all deaths were caused by EOCMVD itself. This study describes a decline in the incidence and mortality of CMVR and EOCMVD during the HAART era of the HIV epidemic. It furthermore serves as a reminder of the importance of EOCMVD as a cause of morbidity and mortality in AIDS in the pre-HAART era.

Avidity of Antibodies to Cytomegalovirus in HIV-Seropositive Patients with and without CMV Retinitis

Antibodies of high avidity may protect the fetus from CMV infection, but the association of avidity with other CMV infections is unknown. To determine if anti-CMV antibody avidity is altered in HIV-seropositive patients, either untreated or treated with HAART, and to determine if alterations in avidity are associated with CMV retinitis, we obtained sera from 164 CMV-seropositive adults: 68 were HIV-seronegative healthy adults and 96 were HIV seropositive. Of the HIV-positive, 57 had no current or prior evidence of CMV retinitis (29 were being treated with HAART, and 28 were receiving no therapy when sampled), and 39 had either active CMV retinitis or were immunorestored by HAART with quiescent CMV retinitis. IgG antibody avidity was determined for each serum run in duplicate using an EIA assay and 5M urea as a dissociating agent. After correction for the significantly higher levels of IgG antibodies to CMV in the HIV-seropositive sera as compared to the normal healthy individuals, both HIV-infected and HIV-uninfected individuals had nearly identical average avidity indices (avidity index = 76). There was also no significant difference in average avidity index between HAART-treated and untreated patients, or between patients with active and immunorestored, quiescent CMV retinitis). These results indicate antibody avidity is unaltered in HIV disease and does not play an important role in the pathogenesis of AIDS-related CMV disease.

The effect of cytomegalovirus retinitis on the quality of life of patients with AIDS in the era of highly active antiretroviral therapy

PURPOSE

To evaluate the effect of cytomegalovirus (CMV) retinitis on quality of life (QOL) in patients with the acquired immune deficiency syndrome (AIDS).

DESIGN

Enrollment data from a multicenter, prospective cohort study.

PARTICIPANTS

Patients >/=13 years of age with AIDS in three groups: no CMV retinitis, 709 patients; long-standing CMV retinitis (diagnosed a median of 34.5 months previously), 212 patients; and newly diagnosed CMV retinitis (diagnosed </=45 days previously), 50 patients.

METHODS

Patients were enrolled at 19 centers throughout the United States. CMV retinitis status was determined by ophthalmoscopy. Vision-related QOL was assessed with a questionnaire designed for patients with CMV retinitis. General health-related QOL was evaluated with a modified version of the Medical Outcomes Survey-HIV instrument. Health utility was measured with the EuroQol instrument.

MAIN OUTCOME MEASURES

Patient-reported vision-related QOL, general health-related QOL, and health utility.

RESULTS

All domains of vision-related QOL were substantially lower in both the long-standing and newly diagnosed CMV retinitis groups than in the group with no CMV retinitis. The long-standing CMV retinitis group was similar to the no CMV retinitis group in most general health-related QOL domains and in health utility measures. The newly diagnosed CMV retinitis group scored substantially worse than the other groups in many of the general health-related QOL domains and in visual analog scale-measured health utility. Adjustment of selected scale scores for demographic characteristics and for CD4(+) T-cell count, human immunodeficiency virus viral load, and use of highly active antiretroviral therapy (HAART) attenuated most of the differences in general health-related QOL, except that physical function scores remained significantly lower in the newly diagnosed CMV retinitis group. Adjustment did not alter the pattern of vision-related QOL results.

CONCLUSIONS

These results suggest that in the HAART era, CMV retinitis is associated with reduced vision-related QOL in patients both with newly diagnosed and with long-standing disease, even though patients with long-standing CMV retinitis seem to have general health-related QOL and health utility similar to that of patients with AIDS who do not have CMV retinitis. Newly diagnosed CMV retinitis also is associated with lower general health-related QOL in most domains and with lower health utility.

HIV-related morbidity and mortality in patients starting protease inhibitors in very advanced HIV disease (CD4 count of < 50 cells/microL): an analysis of 338 clinical events from a randomized clinical trial

BACKGROUND

AIDS defining events occur infrequently in the presence of CD4 counts above 200 cells/microL. It is, however, uncertain for most of the AIDS defining conditions whether this threshold can be considered equally safe in patients with a previously very low CD4 nadir.

METHODS

We evaluated in detail all the AIDS defining events observed during a 48-week clinical trial in 1251 nucleoside reverse transcriptase inhibitor-experienced patients who started protease inhibitors (PIs) at CD4 counts below 50 cells/microL. The type of event, immunological status at the moment of event and time between start of PI treatment and event occurrence were analysed cumulatively and by event type; event rates were calculated.

RESULTS

Concomitant data on CD4 counts were available for 338 AIDS defining events (81% of total events). Median time between start of treatment with PI and event was 94.5 days and median absolute CD4 value at the occurrence of event was 20 per microL. Only 14 events (in 12 patients) were observed above the threshold of 200 CD4 cells/microL. An analysis of the 67 deaths with concomitantly available CD4 counts (57%) showed a median CD4 count of 10 cells/microL, with only four deaths occurring in the presence of a CD4 count above 100 cells/microL.

CONCLUSIONS

Very few clinical AIDS defining conditions were observed in patients who start PIs at very low CD4 counts and with treatment restore absolute values in CD4 counts above 200 cells/microL. This threshold can therefore be considered a clinically effective goal of treatment with respect to occurrence of all AIDS defining conditions in patients starting PIs in very advanced HIV disease.

Preevaluation of clinical trial data: the case of preemptive cytomegalovirus therapy in patients with human immunodeficiency virus

We developed a mathematical simulation model to anticipate outcomes from an upcoming trial of targeted, preemptive cytomegalovirus (CMV) therapy in high-risk, human immunodeficiency virus (HIV)-infected patients identified by means of CMV polymerase chain reaction screening. We estimated the costs and consequences of CMV prophylaxis in patients with CD4(+) counts < or =100 cells/microL under various assumptions regarding disease progression, complication rates, drug effects, and costs. Without CMV preemptive therapy, lifetime costs average $44,600 with expected duration of survival of 19.16 quality-adjusted life-months and 213 CMV cases per 1000 patients. Targeted preemptive therapy with orally administered valganciclovir increases costs and duration of survival to $46,900 and 19.63 quality-adjusted life-months, respectively. CMV cases decrease to 174 per 1000 patients. The cost per quality-adjusted life-year gained is $59,000. This result compares favorably with other strategies in end-stage HIV disease but hinges on valganciclovir cost and efficacy assumptions and the absence of minimally effective salvage antiretroviral therapy for HIV. The upcoming trial should resolve the clinical uncertainty surrounding some of these assumptions.

Incremental cost effectiveness of prophylaxis for cytomegalovirus disease in patients with AIDS

Cytomegalovirus (CMV) disease, an opportunistic complication in patients with AIDS, causes substantial morbidity and has high treatment costs. Although prevention of this disease is highly desirable, incremental cost-effectiveness estimates for proposed prophylactic strategies in the era prior to the availability of highly active antiretroviral therapy (HAART) were unfavourable relative to other specific antimicrobial prophylactic strategies in patients with AIDS. With the availability of HAART, several inputs upon which previous estimates of the incremental cost-effectiveness ratio for anti-CMV prophylaxis were based probably changed substantially. To assess the incremental cost effectiveness of prophylaxis in the HAART era, data are needed on visual outcomes and utility for patients with CMV retinitis and AIDS, on better strategies for identifying subpopulations at high risk for CMV disease and on the prophylactic efficacy of valganciclovir. Cost-effectiveness analysis could potentially contribute by exploring thresholds of population risk, prophylactic effectiveness, and drug pricing in order to identify conditions under which prophylaxis for CMV disease in patients with AIDS could potentially become cost effective.