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Biomedical subjects

Keith Henry

Publications and source records attributed to Keith Henry.

At least 19 recordsLinked to original sources
PubMed2006

A randomized crossover study to determine bioequivalence of generic and brand name nevirapine, zidovudine, and lamivudine in HIV-negative women in India.

Low-cost generic antiretroviral drugs are available in resource-limited settings for treatment of HIV infections. However, few bioequivalence data in specific populations in which these generics are likely to be used are available. We conducted a randomized crossover bioequivalence study of generic and brand name formulations of nevirapine, zidovudine, and lamivudine in HIV-negative Indian women using US Food and Drug Administration (FDA) criteria. Subjects took single doses of all formulations separated by a 14-day washout period. Plasma concentrations were measured over 96 hours during each study period. Average bioequivalence was determined using natural log-transformed maximum concentration (C(max)) and area-under-the-concentration-time curve (AUC) mean ratio data. Fifteen Indian women were enrolled. The 90% confidence intervals for nevirapine (14 subjects) and lamivudine (15 subjects) C(max), AUC from 0 to the last measurable time point (AUC(0-t)), and AUC from 0 to infinity (AUC(0-infinity)) mean ratios and zidovudine (15 subjects) AUC(0-t) and AUC(0-infinity) mean ratios were all within 0.80 to 1.25. However, the 90% confidence interval for zidovudine C(max) mean ratio was 0.70 to 1.46. Generic and brand name nevirapine and lamivudine met FDA average bioequivalence criteria. Lack of average bioequivalence for zidovudine was found for C(max) but is not expected to be clinically significant, because the total AUC values were similar between formulations.

Administration, Oral↗
PubMed2006

Deadly ingestions.

More than 50% of the toxic-exposure calls to US poison centers involve children. Although most of these exposures are nontoxic, there are several products and medications that are widely available to the pediatric population that can lead to severe toxicity or even death. With some of these medications, death or severe symptoms can occur with the ingestion of only a small amount. It is important that the clinician be familiar with presenting signs and symptoms of potentially toxic ingestions and is able to initiate a therapeutic and life-saving intervention. This article reviews some of the deadlier ingestions that children may be exposed to.

Alcohols↗
PubMed2006

A pilot study evaluating time to CD4 T-cell count <350 cells/mm(3) after treatment interruption following antiretroviral therapy +/- interleukin 2: results of ACTG A5102.

BACKGROUND: Although an intermittent antiviral treatment (ART) strategy may limit long-term toxicity and cost, there is concern about the risk for virologic failure, selection of drug resistance mutations, and disease progression. By boosting CD4 T-cell counts, interleukin 2 (IL-2) could safely prolong the duration of treatment interruption (TI) in a CD4-driven strategy. METHODS: The AIDS Clinical Trials Group (ACTG) study A5102 evaluated 3 cycles of IL-2 before TI, on clinical and immunologic outcomes, using a CD4 T-cell count of <350 cells/mm as the threshold for restarting ART. Forty-seven HIV-infected subjects on potent ART with CD4 T-cell counts of > or =500 cells/mm or more and HIV RNA levels of less than 200 copies/mL were randomized to arm A (ART + three 5-day cycles of IL-2 at 4.5 million U, Sc, BID every 8 weeks, n = 23) or arm B (ART alone, n = 24) for 18 weeks (step 1). At the end of step 1, subjects with a CD4 T-cell count of > or =500 cells/mm or more stopped ART until a CD4 count of <350 cells/mm (step 2). CD4 T-cell count, time to return of viremia, and the emergence of drug resistance mutations after TI were compared between study arms. RESULTS: IL-2 recipients maintained higher CD4 counts during TI for 48 weeks with a waning of the CD4 effect by 72 weeks. A sustained CD4 T-cell count of more than 350 cells/mm and more durable TI were associated with a higher nadir CD4 T-cell count before ART and higher naive CD4 T-cell count at entry. After TI, a higher viral set point and drug resistance mutations at virologic rebound were associated with a shorter time to CD4 T-cell count of less than 350 cell/mm. There were no differences in the magnitude of virologic rebound (at week 8 of step 2, median log10 HIV RNA level was 4.23 for arm A and 4.21 for arm B) or the steady-state HIV-1 RNA level after week 8. CONCLUSIONS: IL-2 before TI did not prolong time to CD4 of less than 350 cells/mm. A TI strategy utilizing a CD4 T-cell threshold of less than 350 cells/mm for restarting ART appears generally safe with most subjects in both arms remaining off ART for more than 1 year. Implications of our results for TI strategies include the potential advantage of starting ART at higher CD4 T-cell levels while avoiding any drug resistance and evaluating immunomodulators or drugs to reduce T-cell activation and HIV-1 RNA rebound during the TI.

Adult↗
PubMed2005

Safety of enfuvirtide in combination with an optimized background of antiretrovirals in treatment-experienced HIV-1-infected adults over 48 weeks.

BACKGROUND: Antiretroviral tolerability is a critical factor contributing to treatment outcome. The T-20 Versus Optimized Background Regimen Only (TORO) studies assessed the safety and efficacy of enfuvirtide in treatment-experienced HIV-1-infected patients. METHODS: A total of 997 patients were randomized at a 2:1 ratio to an optimized background antiretroviral regimen plus enfuvirtide (n = 663) or an optimized background regimen alone (control group; n = 334). Control patients could switch to enfuvirtide on virologic failure. RESULTS: In total, 26.5% of patients randomized to enfuvirtide and 36.6% to the control group discontinued study treatment before week 48; the percentage of patients withdrawn for safety reasons (including adverse events [AEs], deaths, and laboratory abnormalities) was 14.0% in the enfuvirtide group and 11.6% in the control group. Injection site reactions (ISRs) occurred in 98% of enfuvirtide patients and led to treatment discontinuation in 4.4%. Treatment-related (defined as possibly, probably, or remotely) AE rates per 100 patient-years were lower with enfuvirtide (96.2) than in the control group (149.9); diarrhea, nausea, and fatigue, the most frequently reported AEs, were significantly less frequent with enfuvirtide than in the control group. Pneumonia was significantly more frequent in patients treated with enfuvirtide (6.7 vs. 0.6 events per 100 patient-years), although the incidence was within expected ranges for this population. Lymphadenopathy was also higher in enfuvirtide-treated patients (7.1 vs. 1.2 events per 100 patient-years) for control patients. CONCLUSION: The addition of enfuvirtide to an optimized background regimen does not exacerbate AEs commonly associated with antiretrovirals. ISRs limited treatment in <5% of patients.

Adult↗
PubMed2005

Durable efficacy of enfuvirtide over 48 weeks in heavily treatment-experienced HIV-1-infected patients in the T-20 versus optimized background regimen only 1 and 2 clinical trials.

BACKGROUND: The T-20 Versus Optimized Background Regimen Only (TORO) 1 and TORO 2 clinical trials are open-label, controlled, parallel-group, phase 3 studies comparing enfuvirtide plus an optimized background (OB) of antiretrovirals (n = 661) with OB alone (n = 334) in treatment-experienced HIV-1-infected patients. METHODS: The primary objective at week 48 was to investigate durability of efficacy, as measured by the percentage of patients maintaining their week 24 response or improving. Efficacy analyses used the intent-to-treat population. RESULTS: A total of 73.7% of patients randomized to the enfuvirtide group remained on treatment through week 48 versus 21.3% originally randomized to the control group. At week 48, a higher proportion of week 24 responders maintained their response or were new responders in the enfuvirtide group than in the control group in each responder category: HIV-1 RNA level > or =1.0 log(10) change from baseline, <400 copies/mL and <50 copies/mL (37.4%, 30.4%, and 18.3% in the enfuvirtide group vs. 17.1%, 12.0%, and 7.8% in the control group, respectively; P < 0.0001 for all comparisons). CD4 cell count increases from baseline were twice as great in the enfuvirtide group as in the control group. CONCLUSION: These data demonstrate durable efficacy of enfuvirtide plus OB over 48 weeks.

Adolescent↗
PubMed2005

HIV-1 subtype diversity in Minnesota.

BACKGROUND: Genetic variation in human immunodeficiency virus (HIV)-1 poses significant public-health and clinical challenges. In North America, subtype B is most prevalent. HIV-1 subtyping is not integrated into routine HIV/acquired immunodeficiency syndrome surveillance in the United States. In 2003, the Minnesota Department of Health piloted HIV-1 subtyping with routine surveillance to describe the existence and variety of non-subtype B strains. METHODS: Targeted HIV-1 subtype surveillance was conducted on 98 African-born HIV-infected patients. Sentinel subtype surveillance was conducted in a Minneapolis sexually transmitted disease clinic on 28 newly diagnosed non-African HIV-positive patients. Subtype determination was based on a partial sequence of the gp41 region of the HIV-1 env gene. RESULTS: Subtyping was successful for 87 of 98 samples from African-born HIV-infected patients; 95% were non-B subtypes. The 7 subtypes observed were consistent with strains endemic in patients' birth regions. Subtyping was also completed for samples from 25 of 28 non-African-born patients; all were subtype B. CONCLUSIONS: Multiple HIV-1 subtypes are present in Minnesota. Our data suggest that most of the HIV cases in Minnesota among African-born patients are non-B subtypes. Population-based surveillance inclusive of groups at high risk for variant strains is needed to monitor the prevalence and variety of HIV subtypes in the United States.

Adult↗
PubMed2004

K103N mutation in antiretroviral therapy-naive African patients infected with HIV type 1.

Most of the information about genetic sequencing and drug susceptibility of human immunodeficiency virus type 1 (HIV-1) is derived from the study of HIV-1 subtype B. Worldwide, most people infected with HIV-1 are infected with non-subtype B viruses and live in developing countries. We report 3 cases of antiretroviral-naive African immigrants infected with HIV-1 strains possessing the K103N mutation in the reverse transcriptase gene, which confers high-level resistance to all nonnucleoside reverse transcriptase inhibitors.

Amino Acid Substitution↗
PubMed2004

Evaluation of the virological and metabolic effects of switching protease inhibitor combination antiretroviral therapy to nevirapine-based therapy for the treatment of HIV infection.

In spite of indisputable benefits, the use of antiretroviral therapy is associated with multiple metabolic complications. Switching to simpler regimens might maintain viral suppression, improve metabolic side effects, and provide insight into the pathogenesis of these complications. Our objective was to carefully characterize the virological and metabolic effects of switching from a successful protease inhibitor (PI)-based antiretroviral regimen to a nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimen with nevirapine (NVP). Forty patients, taking their first successful (less than 40 HIV RNA copies/ml) PI-based regimen, switched their PI to NVP. If patients did not tolerate NVP, substitution with efavirenz was allowed. The duration of the study was 48 weeks. At 12 weeks intervals subjects had multiple virological and metabolic parameters including glucose, insulin, C-peptide, glucagon, proinsulin, blood lipids, and lipoproteins. A subgroup of 18 patients also had body composition evaluations with DEXA scans and MRIs of the abdomen and the thighs as well as insulin tolerance tests. Ninety-five percent of the patients maintained viral suppression (95% CI 88-100%); only one patient failed and another developed hepatitis. There were improvements in glucose (decreased fasting glucose, insulin, and improved insulin tolerance) and lipid metabolism (decreased triglycerides and increased HDL), but no changes in body composition and bone mineral density. Our study supports a pathogenic role for PIs in the development of hypertriglyceridemia and insulin resistance, but a more limited role in the fat redistribution syndrome.

Alkynes↗
PubMed2003

Enfuvirtide (T-20) cross-reactive glycoprotein 41 antibody does not impair the efficacy or safety of enfuvirtide.

The present study investigated the effect of enfuvirtide cross-reactive glycoprotein 41 (gp41) antibody on the efficacy or safety of enfuvirtide in patients participating in 1 of 2 24-week phase 3 clinical trials (T-20 vs. optimized regimen only [TORO] 1 and TORO 2). Serum samples from human immunodeficiency virus-infected patients receiving enfuvirtide plus optimized background (OB) and from patients receiving OB only were evaluated for enfuvirtide cross-reactive gp41 antibodies. Most patients had detectable levels of antibody at baseline; 78% of patients treated with enfuvirtide plus OB had a > or =30% decrease in level of antibody, compared with 43% of patients treated with OB only. Baseline antibody status did not influence virological responses to enfuvirtide-containing treatment. Favorable virological responses were more common among patients who experienced a > or =30% decrease from baseline than among those who experienced either an increase or a lesser decrease. A decrease in virus load correlated with a decrease in level of antibody. Safety was unaffected by the presence of positive antibody at any time point or change in level of antibody. There was no evidence that enfuvirtide cross-reactive gp41 antibody affects the efficacy or safety of enfuvirtide.

Adolescent↗