Trends in uptake of recently approved antiretrovirals within a national healthcare system.

OBJECTIVE: The aim of the study was to describe Veterans Healthcare Administration (VHA) system-wide uptake of three HIV protease inhibitors: atazanavir, darunavir and tipranavir. METHODS: This retrospective cohort study evaluated VHA uptake of three target antiretrovirals and lopinavir/ritonavir in each complete 90-day quarter since approval to December 2007 using VHA HIV Clinical Case Registry data. We assessed uptake using number of new prescriptions, number of providers and facilities prescribing target agents, provider type, clinic type, facility size and location within four US regions. RESULTS: Overall, 6551 HIV-infected veterans received target antiretrovirals. Uptake was generally greatest within the first year after Food and Drug Administration (FDA) approval, and then slightly declined and plateaued. Geographically, early adoption of new antiretroviral drugs tended to occur in the Western USA, as evidenced by comparison of uptake patterns of new antiretrovirals to use of all antiretroviral agents. A small percentage of prescribers of all antiretrovirals were responsible for new prescriptions for target medications, particularly for darunavir and tipranavir. Providers at almost 50% of VHA facilities were prescribing these agents within the first year. CONCLUSIONS: Uptake of new antiretrovirals in the VHA generally reflected overall prescribing of all antiretrovirals, suggesting a lack of VHA impediments to new antiretrovirals in the healthcare system. Some regional variation in uptake among the targeted antiretrovirals occurred over time but tended to resolve after the first several months. Providers responsible for early prescribing of the target medications were limited to a fraction of providers who tended to be physicians who practised in infectious disease (ID) clinics at medium-sized facilities.

Comparative effectiveness of ledipasvir/sofosbuvir ± ribavirin vs. ombitasvir/paritaprevir/ritonavir + dasabuvir ± ribavirin in 6961 genotype 1 patients treated in routine medical practice.

BACKGROUND: Real-world data are needed to inform hepatitis C virus (HCV) treatment decisions. AIM: To assess the comparative effectiveness of ledipasvir/sofosbuvir ± ribavirin (LDV/SOF ± RBV) vs. ombitasvir/paritaprevir/ritonavir + dasabuvir (OPrD) ± RBV in genotype 1 HCV patients treated in routine medical practice. METHODS: Observational intent-to-treat cohort of genotype 1 patients initiating 8 or 12 weeks of LDV/SOF ± RBV or 12 weeks of OPrD ± RBV. Sustained virological response (SVR) required RNA below the limit of quantification at least 10 weeks after end of treatment. RESULTS: 6961 patients initiated LDV/SOF (N = 4478), LDV/SOF + RBV (N = 1269), OPrD (N = 297), and OPrD + RBV (N = 917) at 126 facilities. Intention-to-treat SVR rates were 91.4% (3813/4170) for LDV/SOF, 90.0% (1098/1220) for LDV/SOF + RBV, 95.1% (269/283) for OPrD and 85.8% (746/869) for OPrD + RBV. SVR rates in those completing 8 weeks of LDV/SOF were 91.7% (1223/1333) and 12 weeks of LDV/SOF 94.6% (2475/2615), LDV/SOF + RBV 92.2% (1033/1120), OPrD 98.0% (248/253) and OPrD + RBV 95.5% (705/738). Significant predictors of SVR were African American race (OR 0.71, 95%CI 0.59-0.86, P < 0.001), body mass index (BMI) > 30 kg/m(2) (OR 0.73, 95% CI 0.60-0.89, P = 0.002), FIB4 > 3.25 (OR 0.60, 95% CI 0.49-0.72, P < 0.001), OPrD + RBV compared to LDV/SOF (OR 0.60, 95% CI 0.48-0.76, P < 0.001) and subtype 1b (OR 1.38, 95% CI 1.11-1.71, P = 0.003). For those completing 12 weeks, FIB-4 > 3.25 and high BMI remained significant predictors. CONCLUSIONS: In this robust real-world cohort, SVR rates were similar to clinical trials. FIB-4 > 3.25 and high BMI were significant negative predictors of SVR. Reduced odds of SVR in African Americans and with OPrD + RBV likely arose from excess early discontinuation as these factors were no longer significant, when limited to patients completing a 12-week course.

Effectiveness of sofosbuvir-based regimens in genotype 1 and 2 hepatitis C virus infection in 4026 U.S. Veterans.

BACKGROUND: Real-world effectiveness data are needed to inform hepatitis C virus (HCV) treatment decisions. AIM: To assess sustained virological response (SVR) of sofosbuvir (SOF)-based regimens in routine medical practice. METHODS: Observational, intent-to-treat cohort analysis of genotype 1 and 2 HCV-infected veterans initiating SOF-based regimens with recommended treatment duration of 12 weeks. RESULTS: Four thousand and twenty-six veterans with genotype 1 (N = 3203) and genotype 2 (N = 823) comprise the cohort. SVR rates for genotype 1 were 66.8% for SOF + peginterferon + ribavirin (RBV), 75.3% for SOF + simeprevir (SIM), 74.1% for SOF + SIM + RBV and for genotype 2 were 79.0% for SOF + RBV. Genotype 1 patients were less likely to achieve SVR with BMI ≥30 (OR 0.64, 95% CI 0.49-0.84, P < 0.001), a history of decompensated liver disease (OR 0.51, 95% CI 0.36-0.71, P < 0.001), treatment experience (OR 0.58, 95% CI 0.48-0.71, P < 0.001), APRI >2 (OR 0.44, 95% CI 0.36-0.55, P < 0.001) and with SOF + PEG + RBV compared with SOF + SIM (OR 0.50, 95% CI 0.40-0.62, P < 0.001). Age, sex, race/ethnicity, diabetes and genotype subtype did not predict SVR. Odds of achieving SVR with SOF + SIM + RBV did not differ compared with SOF + SIM (OR 1.03, 95% CI 0.75-1.44, P = 0.86). Genotype 2 patients were less likely to achieve SVR with prior treatment experience (OR 0.55, 95% CI 0.35-0.88, P = 0.009) and APRI >2 (OR 0.39, 95% CI 0.25-0.62, P < 0.001). CONCLUSIONS: In this real-world cohort, SVR rates were lower than in clinical trials. Genotype 1 and 2 HCV-infected patients with advanced liver disease by APRI >2 or FIB-4 > 3.25 were significantly less likely to achieve SVR. For genotype 1, a SOF + SIM ± RBV regimen was associated with a higher likelihood of SVR.

Plasma viremia in human immunodeficiency virus infection: relationship to stage of disease and antiviral treatment.

Quantitative culture of human immunodeficiency virus (HIV) was performed on 121 plasma samples from 76 HIV-infected individuals to determine the sensitivity of the assay at different stages of disease and to measure the effect of antiviral therapy on plasma viremia. Plasma virus was detected in 49 of 76 (64%) of patients, primarily those with AIDS and AIDS-related complex (36 of 38) versus asymptomatic subjects (13 of 38) (p less than 0.001, chi 2). Similarly, plasma cultures were more often positive in patients with less than 250 CD4+ T cells per microliter (38 of 40) than in those with greater than 250 CD4+ T cells per microliter (11 of 36) (p less than 0.001, chi 2). Plasma virus cultures were also more likely to be positive in patients with detectable serum p24 antigen (24 of 26) than in those without detectable p24 antigen (25 of 50) (p = 0.0023, chi 2). An effect of zidovudine (ZDV) treatment on plasma viremia was seen in a comparison of treated and untreated patients with less than 250 CD4+ T cells per microliter. Geometric mean titers of plasma viremia from 16 patients treated with ZDV for more than 3 months were significantly lower than titers from 24 untreated patients (10(1.3) versus 10(2.1), p less than 0.05, Student's t test. A comparison of pre- and posttherapy titers in 33 patients receiving antiviral treatment showed that plasma virus was not detectable at either time in 17 patients; there was a fall in plasma virus titer in 12; and titers were unchanged or increased in 4. In patients with advanced disease, plasma viremia is a potential marker of antiviral drug activity.

CD20 expression is increased on B lymphocytes from HIV-infected individuals.

In studies presented here, we show that expression of the pan B cell marker CD20 is markedly increased on B lymphocytes from HIV-infected individuals and that this increase tends to be greater in individuals with more advanced disease. By using multiparameter FACS analyses to quantitate surface density of CD20 and intracellular glutathione (GSH) levels simultaneously, we further show that the distribution of intracellular glutathione (GSH) levels in B cells of HIV-infected individuals is more heterogeneous than in uninfected controls. Finally, we show that the intracellular GSH levels correlate with CD20 expression on a per-cell basis in all infected individuals. These findings suggest that CD20 expression, which can be precisely measured, may prove to be a useful surrogate marker for monitoring HIV infection.

Purification of hypoxanthine-guanine phosphoribosyltransferase of Plasmodium lophurae.

Hypoxanthine-guanine phosphoribosyltransferase (EC 2.4.2.8) was isolated from the malarial parasite, Plasmodium lophurae. The apparent pI, as determined by chromatofocusing, was 7.6. The native molecular weight was 79,000. The pH profile of HGPRT exhibited a broad pH optimum. With hypoxanthine as substrate maximal activity was achieved from pH 6.0-10.0, and with guanine as substrate maximal activity occurred from pH 7.5-9.5. The enzyme exhibited Michaelis-Menten kinetics with all substrates. The Km values were 3.8 microM (hypoxanthine), 2.4 microM (guanine), 6.2 microM (6-mercaptopurine), 7.6 microM (6-thioguanine), and 360 microM (8-azahypoxanthine). 6-Thioinosine, 9-beta-arabinofuranosylhypoxanthine, 6-chloropurine, xanthine and azaguanine were inhibitors of the P. lophurae enzyme. From the substrate and inhibitor data it appears that the sixth position on the purine ring plays a major role in enzyme activity.

Intracellular glutathione levels in T cell subsets decrease in HIV-infected individuals.

The authors have shown previously that intracellular glutathione (GSH) plays an important role in the regulation of human immunodeficiency virus (HIV) transcription and replication in vitro, through modulation of signal transduction by inflammatory cytokines. Moreover, intracellular GSH levels are known to regulate T-lymphocyte function. In multiparameter FACS studies presented here, we show that relative GSH levels in CD4+ and CD8+ T cells from HIV+ individuals are significantly lower than in corresponding subsets from uninfected controls. These studies define the relative intracellular glutathione (GSH) levels in CD4+ T cells, CD8+ T cells, B cells, and monocytes from 134 HIV-infected individuals and 31 uninfected controls. The greatest decreases in intracellular GSH occur in subsets of T cells in individuals in the later stages of the HIV infection. In AIDS patients, GSH levels are 63% of normal in CD4+ T cells (p less than 0.0001) and are 62% of normal in CD8+ T cells (p less than 0.0001). Similarly, in AIDS-related complex (ARC) patients, GSH levels are 66% of normal in CD4+ T cells (p less than 0.003) and are 69% of normal in CD8+ T cells (p less than 0.003). These findings suggest that low intracellular GSH levels may be an important factor in HIV infection and in the resulting immunodeficiency.

Comparative effectiveness of the hepatitis C virus protease inhibitors boceprevir and telaprevir in a large U.S. cohort.

BACKGROUND: Limited data exist on the effectiveness of boceprevir and telaprevir in routine practice. AIM: To assess the comparative effectiveness of boceprevir and telaprevir regimens. METHODS: In this observational, intent-to-treat cohort analysis of hepatitis C genotype 1-infected veterans initiated on peginterferon/ribavirin and boceprevir (n = 661) or telaprevir (n = 198), we determined sustained virological response (SVR), treatment discontinuation rates and adverse haematological events. Inverse probability-of-treatment weighting (IPTW) was used to estimate the effect of one drug over the other, with matched pairs and unweighted logistic regression on the entire cohort for comparison. RESULTS: Of 835 veterans, SVR occurred in 50% and 52% receiving boceprevir- and telaprevir-based treatment, respectively (P = 0.72). No significant differences occurred among subgroups: cirrhotics (37% vs. 39%, P = 0.94), null responders (23% vs. 18%, P = 0.81), partial responders (39% vs. 58%, P = 0.15) and relapsers (60% vs. 77%, P = 0.11). Early discontinuation rates for boceprevir and telaprevir, respectively, were 31% and 28% by week 24 (P = 0.46) and 54% and 45% by 48 weeks (in those completing at least 28 weeks) (P = 0.14). Choice of telaprevir over boceprevir was significantly associated with SVR in multivariate models (IPTW OR: 1.57, 95% CI: 1.10-2.25, P = 0.01; matched-pairs OR: 1.91, 95% CI: 1.23-3.00, P = 0.004; unweighted OR: 1.50 95% CI: 1.05-2.14, P = 0.02). Rates of haematological adverse events in boceprevir- and telaprevir-treated patients were as follows: anaemia 59% vs. 51%, P = 0.30, thrombocytopenia 41% vs. 48%, P = 0.26, neutropenia 41% vs. 27%, P = 0.04. CONCLUSIONS: Sustained virological response was more likely with telaprevir-based regimens compared with boceprevir-based regimens in routine medical practice, after accounting for patient differences. Early discontinuation and haematological events, however, were similar.

Pretreatment assessment and predictors of hepatitis C virus treatment in US veterans coinfected with HIV and hepatitis C virus.

The US Department of Veterans Affairs (VA) cares for many human immunodeficiency virus/hepatitis C virus (HIV/HCV)-coinfected patients. VA treatment recommendations indicate that all HIV/HCV-coinfected patients undergo evaluation for HCV treatment and list pretreatment assessment tests. We compared clinical practice with these recommendations. We identified 377 HIV/HCV-coinfected veterans who began HCV therapy with pegylated interferon and ribavirin and 4135 HIV/HCV-coinfected veterans who did not but were in VA care at the same facilities during the same period. We compared laboratory and clinical characteristics of the two groups and estimated multivariate logistic regression models of receipt of HCV treatment. Overall, patients had high rates of receipt of tests necessary for HCV pretreatment assessment. Patients starting HCV treatment had higher alanine aminotransferase (ALT), lower creatinine, higher CD4 counts and lower HIV viral loads than patients not starting HCV treatment. In the multivariate model, positive predictors of starting HCV treatment included being non-Hispanic whites, having higher ALTs, lower creatinines, higher HCV viral loads, higher CD4 counts, undetectable HIV viral loads and receiving HIV antiretrovirals. A history of chronic mental illness and a history of hard drug use were negative predictors. Most HIV/HCV-coinfected patients received the necessary HCV pretreatment assessments, although rates of screening for hepatitis A and B immunity can be improved. Having well-controlled HIV disease is by far the most important modifiable factor affecting the receipt of HCV treatment. More research is needed to determine if the observed racial differences in starting HCV treatment reflect biological differences, provider behaviour or patient preference.

Purine nucleoside phosphorylase of the malarial parasite, Plasmodium lophurae.

Purine nucleoside phosphorylase (EC 2.4.2.1, purine nucleoside:orthophosphate ribosyltransferase) was purified and characterized from the malarial parasite, Plasmodium lophurae, using a chromatofocusing (Pharmacia) column and a formycin B affinity column. The apparent isoelectric point of the native protein, as determined by chromatofocusing, was 6.80. By gel filtration and both native and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the native enzyme appeared to be a pentamer with a native molecular weight of 125,300 and a subunit molecular weight of 23,900. The enzyme had a broad pH optimum, pH 5.5-7.5, with maximum activity at pH 6.0-6.5. The enzyme reaction was readily reversible with a Km for inosine of 33 microM and a Km for hypoxanthine of 82 microM. Thioinosine, guanosine, and guanine were also substrates for the plasmodial enzyme, but allopurinol and adenine were not. The parasite enzyme was competitively inhibited by formycin B (Ki = 0.39 microM). Formycin A, azaguanine, and 8-aminoguanosine were not inhibitors of the enzyme.