Last data update: May 20, 2024. (Total: 46824 publications since 2009)
Records 1-27 (of 27 Records) |
Query Trace: Hendrix M[original query] |
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Modeling the probability of HIV infection over time in high-risk seronegative participants receiving placebo in five randomized double-blind placebo-controlled HIV pre-exposure prophylaxis trials: A patient-level pooled analysis
Garcia-Cremades M , Hendrix CW , Jayachandran P , Strydom N , Jarlsberg L , Grant R , Celum CL , Martin M , Baeten JM , Marrazzo J , Anderson P , Choopanya K , Vanichseni S , Glidden DV , Savic RM . Pharmaceutics 2022 14 (9) The World Health Organization recommends pre-exposure prophylaxis (PrEP) for individuals at substantial risk of HIV infection. The aim of this analysis is to quantify the individual risk of HIV infection over time, using a large database of high-risk individuals (n = 5583). We used data from placebo recipients in five phase III PrEP trials: iPrEx, conducted in men who have sex with men and transgender women; VOICE, conducted in young women at high sexual risk; Partners PrEP, conducted in HIV serodiscordant heterosexual couples; TDF2, conducted in high-risk heterosexual men and women; and BTS, conducted in persons who inject drugs. The probability of HIV infection over time was estimated using NONMEM7.4. We identified predictors of HIV risk and found a substantial difference in the risk of infection among and within trial populations, with each study including a mix of low, moderate, and high-risk individuals (p < 0.05). Persons who were female at birth were at a higher risk of HIV infection than people who were male at birth. Final models were integrated in a tool that can assess person-specific risk and simulate cumulative HIV risk over time. These models can be used to optimize future PrEP clinical trials by identifying potential participants at highest risk. |
Characterizing HIV-preventive, plasma tenofovir concentrations. A pooled participant-level data analysis from HIV pre-exposure prophylaxis (PrEP) clinical trials
Garcia-Cremades M , Vuievi K , Hendrix CW , Jayachandran P , Jarlsberg L , Grant R , Celum CL , Martin M , Baeten JM , Marrazzo J , Anderson P , Choopanya K , Vanichseni S , Glidden DV , Savic RM . Clin Infect Dis 2022 75 (11) 1873-1882 BACKGROUND: Daily dosing of tenofovir disoproxil fumarate (TDF), with or without emtricitabine (FTC), has high efficacy in preventing HIV infection when individuals are adherent. The target protective plasma concentration of tenofovir (TFV), however, is not fully understood. The aim of this study is to estimate the protective TFV plasma concentration. METHODS: Participant data from TFV-based daily oral and topical active arms of phase III trials (iPrEx, VOICE and Partners PrEP) were pooled (n=2,950). Individual specific risk scores (low and high risk) of acquiring HIV, based on an earlier placebo analysis, were created. Longitudinal TFV pharmacokinetics (PK), HIV outcome, individual risk scores and the effect of sex at birth data were integrated and analyzed using non-linear mixed effects models (NONMEM). RESULTS: Around 50% of the individuals were estimated to be adherent, which differed from self-reported adherence (90%) and large variation between longitudinal adherence patterns were identified. Following oral administration, the estimated protective TFV trough concentration was substantially higher in high risk females (45.8ng/mL) compared to high risk males (16.1ng/mL) and to low risk individuals (7.5ng/mL). Dosing simulations indicated that high risk women require full adherence to maintain protective levels. CONCLUSIONS: Using the largest PK-HIV outcome database to date, we developed a population adherence-PK-risk-outcome model. Our results indicate that high risk females need higher levels of plasma TFV to achieve HIV protection compared to males. HIV protection exceeds 90% in all populations if daily adherence is achieved. |
Combining information to estimate adherence in studies of pre-exposure prophylaxis for HIV prevention: Application to HPTN 067
Hughes JP , Williamson BD , Krakauer C , Chau G , Ortiz B , Wakefield J , Hendrix C , Amico KR , Holtz TH , Bekker LG , Grant R . Stat Med 2022 41 (6) 1120-1136 In trials of oral HIV pre-exposure prophylaxis (PrEP), multiple approaches have been used to measure adherence, including self-report, pill counts, electronic dose monitoring devices, and biological measures such as drug levels in plasma, peripheral blood mononuclear cells, hair, and/or dried blood spots. No one of these measures is ideal and each has strengths and weaknesses. However, accurate estimates of adherence to oral PrEP are important as drug efficacy is closely tied to adherence, and secondary analyses of trial data within identified adherent/non-adherent subgroups may yield important insights into real-world drug effectiveness. We develop a statistical approach to combining multiple measures of adherence and show in simulated data that the proposed method provides a more accurate measure of true adherence than self-report. We then apply the method to estimate adherence in the ADAPT study (HPTN 067) in South African women. |
Acceptability of a Dapivirine/Placebo Gel Administered Rectally to HIV-1 Seronegative Adults (MTN-026)
Bauermeister JA , Tingler RC , Dominguez C , Dunne EF , Hoesley C , Ho K , Johnson S , Lucas J , Macagna N , Brown E , Gundacker H , Peda M , Jacobson CE , Kramzer L , Singh D , Dezzutti CS , Ayudhya Rpkn , Marzinke MA , Piper J , Devlin B , Nuttall J , McGowan I , Hendrix CW , Cranston RD . AIDS Behav 2021 26 (5) 1333-1346 This study describes the acceptability of a rectal microbicide gel formulation using dapivirine (DPV) among men and women from two countries (United States and Thailand) participating in the Microbicide Trials Network-026 trial. We evaluated participants' acceptability of a rectal DPV/placebo gel as part of a Phase I trial (N = 26; 18 male, 8 female). Participants reported favorable acceptability of the study gel, with most participants reporting that they liked the gel the same (n = 14; 53.8%) or more (n = 11; 42.4%) than when they started the trial. Over half of participants noted that they would prefer the gel over condoms (n = 13; 50%) or that they liked condoms and the gel equally (n = 8; 30.8%). Side effects across products included leakage (n = 8; 30.8%), diarrhea (n = 4; 15.4%), or soiling (n = 1; 3.8%). The high acceptability of a rectal gel underscores its promise as a short-acting biomedical prevention, warranting future research for HIV prevention.Trial Registration: NCT03239483. |
An open-label pharmacokinetic and pharmacodynamic assessment of tenofovir gel and oral emtricitabine / tenofovir disoproxil fumarate
McGowan IM , Kunjara Na Ayudhya RP , Brand RM , Marzinke MA , Hendrix CW , Johnson S , Piper J , Holtz TH , Curlin ME , Chitwarakorn A , Raengsakulrach B , Doncel G , Schwartz Icloud Com J , Rooney JF , Cranston RD . AIDS Res Hum Retroviruses 2021 38 (4) 279-287 The MTN-017 study was undertaken to characterize the safety, acceptability, pharmacokinetic, and pharmacodynamic profile of the reduced-glycerin (RG) 1% tenofovir (RG-TFV) gel compared to oral emtricitabine / tenofovir disoproxil fumarate (FTC/TDF). The study was a Phase 2, three-period, randomized sequence, open-label, expanded safety and acceptability crossover study. In each 8-week study period, HIV-1 uninfected participants were randomized to RG-TFV rectal gel daily; or RG-TFV rectal gel before and after receptive anal intercourse (RAI) (or at least twice weekly in the event of no RAI); or daily oral FTC/TDF. A mucosal substudy was conducted at sites in the USA and Thailand. Samples were collected to evaluate PK and ex vivo biopsy challenge with HIV-1. A total of 195 MSM and transgender women (TW) were enrolled in the parent study and 37 in the mucosal substudy. As previously reported, both products were found to be safe and acceptable. Systemic TFV concentrations were significantly higher following oral exposure and daily rectal administration compared to RAI-associated product use (p<0.001). All three routes of PrEP administration resulted in inhibition of explant infection (p<0.05) and there was a significant inverse correlation between explant HIV-1 p24 and tissue concentrations of TFV and FTC (p<0.0001). Despite significant differences in systemic and mucosal drug concentrations, all three PrEP regimens were able to protect rectal explants from ex vivo HIV infection. These data suggest that there is a rationale for co-development of oral and topical antiretroviral PrEP for HIV prevention. |
A randomized, double blind, placebo-controlled, phase 1 safety and pharmacokinetic study of dapivirine gel (0.05%) administered rectally to HIV-1 seronegative adults (MTN-026)
Cranston RD , Brown E , Bauermeister J , Dunne EF , Hoesley C , Ho K , Johnson S , Lucas J , Dominguez-Islas C , Gundacker H , Peda M , Jacobson CE , Kramzer L , Singh D , Dezzutti CS , Kunjara Na Ayudhya RP , Brand RM , Wang L , Marzinke MA , Piper J , Devlin B , Nuttall J , McGowan I , Hendrix CW . AIDS Res Hum Retroviruses 2021 38 (4) 257-268 INTRODUCTION: Dapivirine (DPV), formulated as vaginal ring, demonstrated HIV risk reduction. MTN-026 explored DPV, formulated as rectal gel, for safety, pharmacokinetics, and acceptability. METHODS: HIV-uninfected men and women aged 18-45 years were enrolled at United States and Thailand sites and randomized 2:1 to receive DPV 0.05% or placebo gel via rectal applicator. A single dose phase was followed by 7 observed daily doses. Plasma, and fluid and tissue from both rectum and cervix were collected at baseline and after the final dose over 72 hours for pharmacokinetics, ex-vivo HIV-1 biopsy challenge, histology, and flow cytometry. RESULTS: 28 participants were randomized; 2 terminated early; 9 were female and 19 male; 12 were white, 11 Asian, 4 black and 1 other race/ethnicity. Mean age was 28.5 and 34.2 years in the DPV and placebo arms, respectively. Thirty adverse events occurred (all Grade 1 or 2, except one unrelated Grade 3) without study arm differences. DPV rectal tissue concentrations (median [interquartile range]) 0.5-1 and 2 hours after a single dose were 256 ng/gm (below limit of quantitation [BLQ], 666) and BLQ (BLQ, 600), respectively, then BLQ (BLQ, BLQ) from 24-72 hours; concentrations following multiple doses were similar. The largest median DPV plasma concentrations were 0.33 ng/mL (0.15, 0.48) after one dose and 0.40 (0.33, 0.49) after seven doses. CONCLUSIONS: The DPV rectal gel was acceptable and without safety concerns. While DPV plasma concentrations were similar to the vaginal ring, rectal tissue concentrations were well below vaginal ring tissue concentrations, suggesting need for reformulation. |
Cabotegravir for HIV prevention in cisgender men and transgender women
Landovitz RJ , Donnell D , Clement ME , Hanscom B , Cottle L , Coelho L , Cabello R , Chariyalertsak S , Dunne EF , Frank I , Gallardo-Cartagena JA , Gaur AH , Gonzales P , Tran HV , Hinojosa JC , Kallas EG , Kelley CF , Losso MH , Madruga JV , Middelkoop K , Phanuphak N , Santos B , Sued O , Valencia Huamaní J , Overton ET , Swaminathan S , Del Rio C , Gulick RM , Richardson P , Sullivan P , Piwowar-Manning E , Marzinke M , Hendrix C , Li M , Wang Z , Marrazzo J , Daar E , Asmelash A , Brown TT , Anderson P , Eshleman SH , Bryan M , Blanchette C , Lucas J , Psaros C , Safren S , Sugarman J , Scott H , Eron JJ , Fields SD , Sista ND , Gomez-Feliciano K , Jennings A , Kofron RM , Holtz TH , Shin K , Rooney JF , Smith KY , Spreen W , Margolis D , Rinehart A , Adeyeye A , Cohen MS , McCauley M , Grinsztejn B . N Engl J Med 2021 385 (7) 595-608 BACKGROUND: Safe and effective long-acting injectable agents for preexposure prophylaxis (PrEP) for human immunodeficiency virus (HIV) infection are needed to increase the options for preventing HIV infection. METHODS: We conducted a randomized, double-blind, double-dummy, noninferiority trial to compare long-acting injectable cabotegravir (CAB-LA, an integrase strand-transfer inhibitor [INSTI]) at a dose of 600 mg, given intramuscularly every 8 weeks, with daily oral tenofovir disoproxil fumarate-emtricitabine (TDF-FTC) for the prevention of HIV infection in at-risk cisgender men who have sex with men (MSM) and in at-risk transgender women who have sex with men. Participants were randomly assigned (1:1) to receive one of the two regimens and were followed for 153 weeks. HIV testing and safety evaluations were performed. The primary end point was incident HIV infection. RESULTS: The intention-to-treat population included 4566 participants who underwent randomization; 570 (12.5%) identified as transgender women, and the median age was 26 years (interquartile range, 22 to 32). The trial was stopped early for efficacy on review of the results of the first preplanned interim end-point analysis. Among 1698 participants from the United States, 845 (49.8%) identified as Black. Incident HIV infection occurred in 52 participants: 13 in the cabotegravir group (incidence, 0.41 per 100 person-years) and 39 in the TDF-FTC group (incidence, 1.22 per 100 person-years) (hazard ratio, 0.34; 95% confidence interval, 0.18 to 0.62). The effect was consistent across prespecified subgroups. Injection-site reactions were reported in 81.4% of the participants in the cabotegravir group and in 31.3% of those in the TDF-FTC group. In the participants in whom HIV infection was diagnosed after exposure to CAB-LA, INSTI resistance and delays in the detection of HIV infection were noted. No safety concerns were identified. CONCLUSIONS: CAB-LA was superior to daily oral TDF-FTC in preventing HIV infection among MSM and transgender women. Strategies are needed to prevent INSTI resistance in cases of CAB-LA PrEP failure. (Funded by the National Institute of Allergy and Infectious Diseases and others; HPTN 083 ClinicalTrials.gov number, NCT02720094.). |
Assessing the Performance of Dried-Blood-Spot DNA Extraction Methods in Next Generation Sequencing.
Hendrix MM , Cuthbert CD , Cordovado SK . Int J Neonatal Screen 2020 6 (2) 1-15 An increasing number of newborn screening laboratories in the United States and abroad are moving towards incorporating next-generation sequencing technology, or NGS, into routine screening, particularly for cystic fibrosis. As more programs utilize this technology for both cystic fibrosis and beyond, it is critical to identify appropriate DNA extraction methods that can be used with dried blood spots that will result in consistent, high-quality sequencing results. To provide comprehensive quality assurance and technical assistance to newborn screening laboratories wishing to incorporate NGS assays, CDC's Newborn Screening and Molecular Biology Branch designed a study to evaluate the performance of nine commercial or laboratory-developed DNA extraction methods that range from a highly purified column extraction to a crude detergent-based no-wash boil prep. The DNA from these nine methods was used in two NGS library preparations that interrogate the CFTR gene. All DNA extraction methods including the cruder preps performed reasonably well with both library preps. One lower-concentration, older sample was excluded from one of the assay evaluations due to poor performance across all DNA extraction methods. When 84 samples, versus eight, were run on a flow cell, the DNA quality and quantity were more significant variables. |
Short and long-term pharmacologic measures of HIV pre-exposure prophylaxis use among high-risk men who have sex with men in HPTN 067/ADAPT
Velloza J , Bacchetti P , Hendrix CW , Murnane P , Hughes JP , Li M , Curlin M , Holtz TH , Mannheimer S , Marzinke MA , Amico KR , Liu A , Piwowar-Manning E , Eshleman SH , Dye BJ , Gandhi M , Grant RM . J Acquir Immune Defic Syndr 2019 82 (2) 149-158 BACKGROUND: The effectiveness of oral emtricitabine (FTC)/tenofovir (TFV) disoproxil fumarate (TDF)-based HIV pre-exposure prophylaxis (PrEP) depends on adherence. Pharmacologic measures help interpret patterns and predictors of PrEP adherence. SETTING: We analyzed data from the sub-sample of men who have sex with men (MSM) enrolled in HPTN 067/ADAPT in Bangkok, Thailand, and Harlem, NY, U.S. METHODS: After a five-week directly observed therapy period, participants were randomized to daily, time-driven, or event-driven PrEP. Follow-up occurred at weeks 4, 12, and 24 post-randomization. Plasma and hair FTC/TFV levels indicated short and long-term PrEP use, respectively. Electronic pill bottle data (Wisepill) were collected weekly. Pearson correlation coefficients between PrEP use measures were calculated; linear mixed models assessed predictors of plasma and hair drug concentrations. RESULTS: Among 350 participants (median age 31 years, interquartile range [IQR]: 25-38), 49.7% were from Harlem, half had less than college education, and 21% reported heavy alcohol use. In multivariable models, being enrolled in Harlem, being in non-daily arms, and having less than college education were associated with lower hair FTC/TFV concentrations; heavy alcohol use was associated with higher concentrations. Similar results were found for plasma concentrations by site and arm, but older age and greater number of sex partners were associated with higher concentrations. Hair and plasma FTC/TFV concentrations were moderately correlated with Wisepill data (r>/=0.29) across visits. CONCLUSION: In HPTN067, plasma, hair, and Wisepill data correlated with one another and served as complementary adherence measures. Site, arm, education, age, alcohol, and sexual behavior influenced patterns of adherence. |
Discovery of genetic variants of the kinases that activate tenofovir among individuals in the United States, Thailand, and South Africa: HPTN067.
Figueroa DB , Tillotson J , Li M , Piwowar-Manning E , Hendrix CW , Holtz TH , Bokoch K , Bekker LG , van Griensven F , Mannheimer S , Hughes JP , Grant RM , Bumpus NN . PLoS One 2018 13 (4) e0195764 Tenofovir (TFV), a nucleotide reverse transcriptase inhibitor, requires two phosphorylation steps to form a competitive inhibitor of HIV reverse transcriptase. Adenylate kinase 2 (AK2) has been previously demonstrated to phosphorylate tenofovir to tenofovir-monophosphate, while creatine kinase, muscle (CKM), pyruvate kinase, muscle (PKM) and pyruvate kinase, liver and red blood cell (PKLR) each have been found to phosphorylate tenofovir-monophosphate to the pharmacologically active tenofovir-diphosphate. In the present study, genomic DNA isolated from dried blood spots collected from 505 participants from Bangkok, Thailand; Cape Town, South Africa; and New York City, USA were examined for variants in AK2, CKM, PKM, and PKLR using next-generation sequencing. The bioinformatics tools SIFT and PolyPhen predicted that 19 of the 505 individuals (3.7% frequency) carried variants in at least one kinase that would result in a decrease or loss of enzymatic activity. To functionally test these predictions, AK2 and AK2 variants were expressed in and purified from E. coli, followed by investigation of their activities towards tenofovir. Interestingly, we found that purified AK2 had the ability to phosphorylate tenofovir-monophosphate to tenofovir-diphosphate in addition to phosphorylating tenofovir to tenofovir-monophosphate. Further, four of the six AK2 variants predicted to result in a loss or decrease of enzyme function exhibited a >/=30% decrease in activity towards tenofovir in our in vitro assays. Of note, an AK2 K28R variant resulted in a 72% and 81% decrease in the formation of tenofovir-monophosphate and tenofovir-diphosphate, respectively. These data suggest that there are naturally occurring genetic variants that could potentially impact TFV activation. |
Daily and nondaily oral preexposure prophylaxis in men and transgender women who have sex with men: The Human Immunodeficiency Virus Prevention Trials Network 067/ADAPT Study
Grant RM , Mannheimer S , Hughes JP , Hirsch-Moverman Y , Loquere A , Chitwarakorn A , Curlin ME , Li M , Amico KR , Hendrix CW , Anderson PL , Dye BJ , Marzinke MA , Piwowar-Manning E , McKinstry L , Elharrar V , Stirratt M , Rooney JF , Eshleman SH , McNicholl JM , van Griensven F , Holtz TH . Clin Infect Dis 2018 66 (11) 1712-1721 Background: Nondaily dosing of oral preexposure prophylaxis (PrEP) may provide equivalent coverage of sex events compared with daily dosing. Methods: At-risk men and transgender women who have sex with men were randomly assigned to 1 of 3 dosing regimens: 1 tablet daily, 1 tablet twice weekly with a postsex dose (time-driven), or 1 tablet before and after sex (event-driven), and were followed for coverage of sex events with pre- and postsex dosing measured by weekly self-report, drug concentrations, and electronic drug monitoring. Results: From July 2012 to May 2014, 357 participants were randomized. In Bangkok, the coverage of sex events was 85% for the daily arm compared with 84% for the time-driven arm (P = .79) and 74% for the event-driven arm (P = .02). In Harlem, coverage was 66%, 47% (P = .01), and 52% (P = .01) for these groups. In Bangkok, PrEP medication concentrations in blood were consistent with use of >/=2 tablets per week in >95% of visits when sex was reported in the prior week, while in Harlem, such medication concentrations occurred in 48.5% in the daily arm, 30.9% in the time-driven arm, and 16.7% in the event-driven arm (P < .0001). Creatinine elevations were more common in the daily arm (P = .050), although they were not dose limiting. Conclusions: Daily dosing recommendations increased coverage and protective drug concentrations in the Harlem cohort, while daily and nondaily regimens led to comparably favorable outcomes in Bangkok, where participants had higher levels of education and employment. Clinical Trials Registration: NCT01327651. |
Novel multipurpose pod-intravaginal ring for the prevention of HIV, HSV, and unintended pregnancy: Pharmacokinetic evaluation in a macaque model
Smith JM , Moss JA , Srinivasan P , Butkyavichene I , Gunawardana M , Fanter R , Miller CS , Sanchez D , Yang F , Ellis S , Zhang J , Marzinke MA , Hendrix CW , Kapoor A , Baum MM . PLoS One 2017 12 (10) e0185946 Globally, women bear an uneven burden for sexual HIV acquisition. Results from two clinical trials evaluating intravaginal rings (IVRs) delivering the antiretroviral agent dapivirine have shown that protection from HIV infection can be achieved with this modality, but high adherence is essential. Multipurpose prevention technologies (MPTs) can potentially increase product adherence by offering protection against multiple vaginally transmitted infections and unintended pregnancy. Here we describe a coitally independent, long-acting pod-IVR MPT that could potentially prevent HIV and HSV infection as well as unintended pregnancy. The pharmacokinetics of MPT pod-IVRs delivering tenofovir alafenamide hemifumarate (TAF2) to prevent HIV, acyclovir (ACV) to prevent HSV, and etonogestrel (ENG) in combination with ethinyl estradiol (EE), FDA-approved hormonal contraceptives, were evaluated in pigtailed macaques (N = 6) over 35 days. Pod IVRs were exchanged at 14 days with the only modification being lower ENG release rates in the second IVR. Plasma progesterone was monitored weekly to determine the effect of ENG/EE on menstrual cycle. The mean in vivo release rates (mg d-1) for the two formulations over 30 days ranged as follows: TAF2 0.35-0.40; ACV 0.56-0.70; EE 0.03-0.08; ENG (high releasing) 0.63; and ENG (low releasing) 0.05. Mean peak progesterone levels were 4.4 +/- 1.8 ng mL-1 prior to IVR insertion and 0.075 +/- 0.064 ng mL-1 for 5 weeks after insertion, suggesting that systemic EE/ENG levels were sufficient to suppress menstruation. The TAF2 and ACV release rates and resulting vaginal tissue drug concentrations (medians: TFV, 2.4 ng mg-1; ACV, 0.2 ng mg-1) may be sufficient to protect against HIV and HSV infection, respectively. This proof of principle study demonstrates that MPT-pod IVRs could serve as a potent biomedical prevention tool to protect women's sexual and reproductive health and may increase adherence to HIV PrEP even among younger high-risk populations. |
High levels of adherence to a rectal microbicide gel and to oral Pre-Exposure Prophylaxis (PrEP) achieved in MTN-017 among men who have sex with men (MSM) and transgender women
Carballo-Dieguez A , Balan IC , Brown W 3rd , Giguere R , Dolezal C , Leu CS , Marzinke MA , Hendrix CW , Piper JM , Richardson BA , Grossman C , Johnson S , Gomez K , Horn S , Kunjara Na Ayudhya RP , Patterson K , Jacobson C , Bekker LG , Chariyalertsak S , Chitwarakorn A , Gonzales P , Holtz TH , Liu A , Mayer KH , Zorrilla C , Lama J , McGowan I , Cranston RD . PLoS One 2017 12 (7) e0181607 Trials to assess microbicide safety require strict adherence to prescribed regimens. If adherence is suboptimal, safety cannot be adequately assessed. MTN-017 was a phase 2, randomized sequence, open-label, expanded safety and acceptability crossover study comparing 1) daily oral emtricitabine/tenofovir disoproxil fumarate (FTC/TDF), 2) daily use of reduced-glycerin 1% tenofovir (RG-TFV) gel applied rectally, and 3) RG-TFV gel applied before and after receptive anal intercourse (RAI)-if participants had no RAI in a week, they were asked to use two doses of gel within 24 hours. Product use was assessed by mixed methods including unused product return count, text messaging reports, and qualitative plasma TFV pharmacokinetic (PK) results. Convergence interviews engaged participants in determining the most accurate number of doses used based on product count and text messaging reports. Client-centered adherence counseling was also used. Participants (N = 187) were men who have sex with men and transgender women enrolled in the United States (42%), Thailand (29%), Peru (19%) and South Africa (10%). Mean age was 31.4 years (range 18-64 years). Based on convergence interviews, over an 8-week period, 94% of participants had ≥80% adherence to daily tablet, 41% having perfect adherence; 83% had ≥80% adherence to daily gel, 29% having perfect adherence; and 93% had ≥80% adherence to twice-weekly use during the RAI-associated gel regimen, 75% having perfect adherence and 77% having ≥80% adherence to gel use before and after RAI. Only 4.4% of all daily product PK results were undetectable and unexpected (TFV concentrations <0.31 ng/mL) given self-reported product use near sampling date. The mixed methods adherence measurement indicated high adherence to product use in all three regimens. Adherence to RAI-associated rectal gel use was as high as adherence to daily oral PrEP. A rectal microbicide gel, if efficacious, could be an alternative for individuals uninterested in daily oral PrEP. |
Newborn Screening Quality Assurance Program for CFTR Mutation Detection and Gene Sequencing to Identify Cystic Fibrosis.
Hendrix MM , Foster SL , Cordovado SK . J Inborn Errors Metab Screen 2016 4 All newborn screening laboratories in the United States and many worldwide screen for cystic fibrosis. Most laboratories use a second-tier genotyping assay to identify a panel of mutations in the CF transmembrane regulator (CFTR) gene. Centers for Disease Control and Prevention's Newborn Screening Quality Assurance Program houses a dried blood spot repository of samples containing CFTR mutations to assist newborn screening laboratories and ensure high-quality mutation detection in a highthroughput environment. Recently, CFTR mutation detection has increased in complexity with expanded genotyping panels and gene sequencing. To accommodate the growing quality assurance needs, the repository samples were characterized with several multiplex genotyping methods, Sanger sequencing, and 3 next-generation sequencing assays using a high-throughput, lowconcentration DNA extraction method. The samples performed well in all of the assays, providing newborn screening laboratories with a resource for complex CFTR mutation detection and next-generation sequencing as they transition to new methods. |
Levels of intracellular phosphorylated tenofovir and emtricitabine correlate with natural substrate concentrations in peripheral blood mononuclear cells of persons prescribed daily oral TruvadaTM for HIV pre-exposure prophylaxis
Haaland RE , Holder A , Pau CP , Swaims-Kohlmeier A , Dawson C , Smith DK , Segolodi TM , Thigpen MC , Paxton LA , Parsons TL , Hendrix CW , Hart CE . J Acquir Immune Defic Syndr 2017 75 (3) e86-e88 Successful clinical trials of antiretroviral pre-exposure prophylaxis (PrEP) to prevent HIV infection have been reported in heterosexual men and women, men who have sex with men (MSM), and injection drug users1. A daily oral drug regimen containing nucleoside reverse transcriptase inhibitors (NRTIs) tenofovir disoproxil fumarate (TDF) alone or in combination with emtricitabine (FTC) have been effective when participant adherence is high1. Analysis of PrEP dosing patterns estimate taking at least four TDF doses per week provides 96% protection from HIV infection and at least two doses per week provides 76% protection in MSM and transgender women2, though some estimate more frequent dosing in heterosexual women may be needed3. TDF and FTC require phosphorylation in HIV target cells to tenofovir-diphosphate (TFV-DP) and emtricitabine-triphosphate (FTC-TP) to provide PrEP protection as competitive analogs of naturally occurring deoxyadenosine triphosphate (dATP) and deoxycytidine triphosphate (dCTP), respectively. However, it is unclear if physiological conditions that increase dNTP concentrations can affect pharmacokinetics (PK) and pharmacodynamics (PD) of NRTIs. This may be particularly relevant when cellular deoxynucleoside triphosphate (dNTP) pools in HIV target cells increase in response to immune activation. Decreased ratios of phosphorylated NRTIs to their respective dNTPs have been associated with cell activation in vitro and in nonhuman primate studies4,5, yet this observation remains unexplored in PK and PD studies that measured intracellular drug6-8. The study presented here compared dATP and dCTP concentrations to TFV-DP and FTC-TP in peripheral blood mononuclear cell (PBMCs) of persons using daily oral Truvada™ during a successful HIV PrEP study. We further examined if variations among intracellular drug:dNTP ratios were related to lymphocyte activation. |
MTN-017: A rectal phase 2 extended safety and acceptability study of tenofovir reduced-glycerin 1% gel
Cranston RD , Lama JR , Richardson BA , Carballo-Dieguez A , Kunjara Na Ayudhya RP , Liu K , Patterson KB , Leu CS , Galaska B , Jacobson CE , Parikh UM , Marzinke MA , Hendrix CW , Johnson S , Piper JM , Grossman C , Ho KS , Lucas J , Pickett J , Bekker LG , Chariyalertsak S , Chitwarakorn A , Gonzales P , Holtz TH , Liu AY , Mayer KH , Zorrilla C , Schwartz JL , Rooney J , McGowan I . Clin Infect Dis 2016 64 (5) 614-620 BACKGROUND: HIV disproportionately affects men who have sex with men (MSM) and transgender women (TGW). Safe and acceptable topical HIV prevention methods that target the rectum are needed. METHODS: MTN-017 was a Phase 2, three-period, randomized sequence, open-label, expanded safety and acceptability crossover study comparing rectally applied reduced-glycerin (RG) 1% tenofovir (TFV) and oral emtricitabine/TFV disoproxil fumarate (FTC/TDF). In each 8-week study period participants were randomized to RG-TFV rectal gel daily; or RG-TFV rectal gel before and after receptive anal intercourse (RAI) (or at least twice weekly in the event of no RAI); or daily oral FTC/TDF. RESULTS: MSM and TGW (n=195) were enrolled from 8 sites in the United States, Thailand, Peru, and South Africa with mean age of 31.1 years (range 18-64). There were no differences in Grade 2 or higher adverse event rates in participants using daily gel (Incidence Rate Ratio (IRR): 1.09, p=0.59) or RAI gel (IRR: 0.90, p=0.51) compared to FTC/TDF. High adherence (≥80% of prescribed doses as assessed by unused product return and SMS reports) was less likely in the daily gel regimen (Odds Ratio (OR): 0.35, p<0.001) and participants reported less likelihood of future daily gel use for HIV protection compared to FTC/TDF (OR: 0.38, p<0.001). CONCLUSIONS: Rectal application of RG TFV gel was safe in MSM and TGW. Adherence and product use likelihood were similar for the intermittent gel and daily oral FTC/TDF regimens, but lower for the daily gel regimen. |
Selecting quality service dogs (part 1): morphological and health considerations
Parenti L , Wilson M , Foreman AM , Wirth O , Meade BJ . APDT Chron Dog 2015 2015 71-77 Service dogs include dogs for mobility, vision, hearing, developmental disabilities, diabetic alert, seizure alert, and psychiatric support. They are trained to "provide work or perform tasks related to an individual's disability." When accompanied by a service dog, the individual with a disability is afforded some public access protections (Parenti, Foreman, Meade, and Wirth, 2013). Current demand for service dogs outweighs supply (M. Winkle, Crowe, and Hendrix, 2012), and average wait times of up to three years for a well-trained dog are not uncommon. Service dogs are generally trained for a minimum of 18 months, and training can cost anywhere from $10,000 to $20,000 (Allen and Blascovich, 1996. According to some estimates, only 50% of dogs entering training progress to the level of service dog (Batt, Batt, Baguley, and McGreevy, 2008), increasing the cost of training and limiting the number of available dogs. Hereditary diseases and behavioral problems are the most common reasons for a dog to be released from a training program (Wahl, Herbst, Tsai, and Murphy, 2008). Targeted selection and breeding of physically and behaviorally healthy dogs would allow organizations to allocate their resources more efficiently, reduce training costs, and increase the supply of service dogs to those in need. Service dog training programs nationwide can benefit from selecting and breeding dogs based on characteristics relevant to their service dog specialty. This is the first of three articles on the selection and breeding of dogs for service work. The current article addresses morphological and health considerations; the remaining articles will focus on behavior and temperament characteristics and research in the field of service dog training. |
Improving newborn screening for cystic fibrosis using next-generation sequencing technology: a technical feasibility study.
Baker MW , Atkins AE , Cordovado SK , Hendrix M , Earley MC , Farrell PM . Genet Med 2015 18 (3) 231-8 PURPOSE: Many regions have implemented newborn screening (NBS) for cystic fibrosis (CF) using a limited panel of cystic fibrosis transmembrane regulator (CFTR) mutations after immunoreactive trypsinogen (IRT) analysis. We sought to assess the feasibility of further improving the screening using next-generation sequencing (NGS) technology. METHODS: An NGS assay was used to detect 162 CFTR mutations/variants characterized by the CFTR2 project. We used 67 dried blood spots (DBSs) containing 48 distinct CFTR mutations to validate the assay. NGS assay was retrospectively performed on 165 CF screen-positive samples with one CFTR mutation. RESULTS: The NGS assay was successfully performed using DNA isolated from DBSs, and it correctly detected all CFTR mutations in the validation. Among 165 screen-positive infants with one CFTR mutation, no additional disease-causing mutation was identified in 151 samples consistent with normal sweat tests. Five infants had a CF-causing mutation that was not included in this panel, and nine with two CF-causing mutations were identified. CONCLUSION: The NGS assay was 100% concordant with traditional methods. Retrospective analysis results indicate an IRT/NGS screening algorithm would enable high sensitivity, better specificity and positive predictive value (PPV). This study lays the foundation for prospective studies and for introducing NGS in NBS laboratories. |
Single-agent tenofovir versus combination emtricitabine plus tenofovir for pre-exposure prophylaxis for HIV-1 acquisition: an update of data from a randomised, double-blind, phase 3 trial
Baeten JM , Donnell D , Mugo NR , Ndase P , Thomas KK , Campbell JD , Wangisi J , Tappero JW , Bukusi EA , Cohen CR , Katabira E , Ronald A , Tumwesigye E , Were E , Fife KH , Kiarie J , Farquhar C , John-Stewart G , Kidoguchi L , Coombs RW , Hendrix C , Marzinke MA , Frenkel L , Haberer JE , Bangsberg D , Celum C . Lancet Infect Dis 2014 14 (11) 1055-1064 BACKGROUND: Antiretroviral pre-exposure prophylaxis (PrEP), with daily oral tenofovir disoproxil fumarate or tenofovir disoproxil fumarate in combination with emtricitabine, has been shown to be efficacious for HIV-1 prevention. Although the use of more than one antiretroviral agent is essential for effective HIV-1 treatment, more than one agent might not be required for effective prophylaxis. We assessed the efficacy of single-agent tenofovir disoproxil fumarate relative to combination emtricitabine plus tenofovir disoproxil fumarate as PrEP. METHODS: We did a randomised, double-blind, placebo-controlled three-group phase 3 trial of daily oral tenofovir disoproxil fumarate and emtricitabine plus tenofovir disoproxil fumarate PrEP in HIV-1 uninfected individuals in heterosexual HIV-1 serodiscordant couples from Kenya and Uganda. After an interim review, the trial's placebo group was discontinued and thereafter the active groups were continued, and participants initially randomly assigned to placebo were offered rerandomisation in a 1:1 ratio to tenofovir disoproxil fumarate or emtricitabine plus tenofovir disoproxil fumarate as PrEP. The primary endpoints were HIV-1 seroconversion and safety. This trial is registered with ClinicalTrials.gov, number NCT00557245. FINDINGS: 4410 (99.6%) of 4427 couples received tenofovir disoproxil fumarate or emtricitabine plus tenofovir disoproxil fumarate and were followed up for HIV-1 acquisition. Of 52 incident HIV-1 infections, 31 occurred in individuals assigned tenofovir disoproxil fumarate (incidence 0.71 cases per 100 person-years) and 21 were in those assigned emtricitabine plus tenofovir disoproxil fumarate (0.48 cases per 100 person-years); HIV-1 incidence in the placebo group until discontinuation was two cases per 100 person-years. HIV-1 prevention efficacy with emtricitabine plus tenofovir disoproxil fumarate was not significantly different from that of tenofovir disoproxil fumarate alone (hazard ratio [HR] 0.67, 95% CI 0.39-1.17; p=0.16). Detection of tenofovir in plasma samples, compared with no detection and as measured in seroconverters and a subset of non-seroconverters, was associated with an 85% relative risk reduction in HIV-1 acquisition for the tenofovir disoproxil fumarate group (HR 0.15, 95% CI 0.06-0.37; p<0.0001) and 93% for the emtricitabine plus tenofovir disoproxil fumarate group (0.07, 0.02-0.23; p<0.0001). No significant differences were noted in the frequency of deaths, serious adverse events, or serum creatinine and phosphorus abnormalities between the two groups. INTERPRETATION: These results do not rule out the potential for a slight difference in HIV-1 protection with tenofovir disoproxil fumarate compared with emtricitabine plus tenofovir disoproxil fumarate, but show that once-daily oral tenofovir disoproxil fumarate or emtricitabine plus tenofovir disoproxil fumarate regimens both provide high protection against HIV-1 acquisition in heterosexual men and women. FUNDING: Bill & Melinda Gates Foundation and US National Institutes of Health. |
Undisclosed antiretroviral drug use in a multinational clinical trial (HIV Prevention Trials Network 052)
Fogel JM , Wang L , Parsons TL , Ou SS , Piwowar-Manning E , Chen Y , Mudhune VO , Hosseinipour MC , Kumwenda J , Hakim JG , Chariyalertsak S , Panchia R , Sanne I , Kumarasamy N , Grinsztejn B , Makhema J , Pilotto J , Santos BR , Mayer KH , McCauley M , Gamble T , Bumpus NN , Hendrix CW , Cohen MS , Eshleman SH . J Infect Dis 2013 208 (10) 1624-8 The HIV Prevention Trials Network 052 study enrolled serodiscordant couples. Index participants infected with human immunodeficiency virus reported no prior antiretroviral (ARV) treatment at enrollment. ARV drug testing was performed retrospectively using enrollment samples from a subset of index participants. ARV drugs were detected in 45 of 96 participants (46.9%) with an undetectable viral load, 2 of 48 (4.2%) with a low viral load, and 1 of 65 (1.5%) with a high viral load (P < .0001); they were also detected in follow-up samples from participants who were not receiving study-administered treatment. ARV drug testing may be useful in addition to self-report of ARV drug use in some clinical trial settings. |
Antiretroviral prophylaxis for HIV infection in injecting drug users in Bangkok, Thailand (the Bangkok Tenofovir Study): a randomised, double-blind, placebo-controlled phase 3 trial
Choopanya K , Martin M , Suntharasamai P , Sangkum U , Mock PA , Leethochawalit M , Chiamwongpaet S , Kitisin P , Natrujirote P , Kittimunkong S , Chuachoowong R , Gvetadze RJ , McNicholl JM , Paxton LA , Curlin ME , Hendrix CW , Vanichseni S . Lancet 2013 381 (9883) 2083-90 BACKGROUND: Antiretroviral pre-exposure prophylaxis reduces sexual transmission of HIV. We assessed whether daily oral use of tenofovir disoproxil fumarate (tenofovir), an antiretroviral, can reduce HIV transmission in injecting drug users. METHODS: In this randomised, double-blind, placebo-controlled trial, we enrolled volunteers from 17 drug-treatment clinics in Bangkok, Thailand. Participants were eligible if they were aged 20-60 years, were HIV-negative, and reported injecting drugs during the previous year. We randomly assigned participants (1:1; blocks of four) to either tenofovir or placebo using a computer-generated randomisation sequence. Participants chose either daily directly observed treatment or monthly visits and could switch at monthly visits. Participants received monthly HIV testing and individualised risk-reduction and adherence counselling, blood safety assessments every 3 months, and were offered condoms and methadone treatment. The primary efficacy endpoint was HIV infection, analysed by modified intention-to-treat analysis. This trial is registered with ClinicalTrials.gov, number NCT00119106. FINDINGS: Between June 9, 2005, and July 22, 2010, we enrolled 2413 participants, assigning 1204 to tenofovir and 1209 to placebo. Two participants had HIV at enrolment and 50 became infected during follow-up: 17 in the tenofovir group (an incidence of 0.35 per 100 person-years) and 33 in the placebo group (0.68 per 100 person-years), indicating a 48.9% reduction in HIV incidence (95% CI 9.6-72.2; p=0.01). The occurrence of serious adverse events was much the same between the two groups (p=0.35). Nausea was more common in participants in the tenofovir group than in the placebo group (p=0.002). INTERPRETATION: In this study, daily oral tenofovir reduced the risk of HIV infection in people who inject drugs. Pre-exposure prophylaxis with tenofovir can now be considered for use as part of an HIV prevention package for people who inject drugs. FUNDING: US Centers for Disease Control and Prevention and the Bangkok Metropolitan Administration. |
Antiretroviral prophylaxis for HIV prevention in heterosexual men and women
Baeten JM , Donnell D , Ndase P , Mugo NR , Campbell JD , Wangisi J , Tappero JW , Bukusi EA , Cohen CR , Katabira E , Ronald A , Tumwesigye E , Were E , Fife KH , Kiarie J , Farquhar C , John-Stewart G , Kakia A , Odoyo J , Mucunguzi A , Nakku-Joloba E , Twesigye R , Ngure K , Apaka C , Tamooh H , Gabona F , Mujugira A , Panteleeff D , Thomas KK , Kidoguchi L , Krows M , Revall J , Morrison S , Haugen H , Emmanuel-Ogier M , Ondrejcek L , Coombs RW , Frenkel L , Hendrix C , Bumpus NN , Bangsberg D , Haberer JE , Stevens WS , Lingappa JR , Celum C . N Engl J Med 2012 367 (5) 399-410 BACKGROUND: Antiretroviral preexposure prophylaxis is a promising approach for preventing human immunodeficiency virus type 1 (HIV-1) infection in heterosexual populations. METHODS: We conducted a randomized trial of oral antiretroviral therapy for use as preexposure prophylaxis among HIV-1-serodiscordant heterosexual couples from Kenya and Uganda. The HIV-1-seronegative partner in each couple was randomly assigned to one of three study regimens--once-daily tenofovir (TDF), combination tenofovir-emtricitabine (TDF-FTC), or matching placebo--and followed monthly for up to 36 months. At enrollment, the HIV-1-seropositive partners were not eligible for antiretroviral therapy, according to national guidelines. All couples received standard HIV-1 treatment and prevention services. RESULTS: We enrolled 4758 couples, of whom 4747 were followed: 1584 randomly assigned to TDF, 1579 to TDF-FTC, and 1584 to placebo. For 62% of the couples followed, the HIV-1-seronegative partner was male. Among HIV-1-seropositive participants, the median CD4 count was 495 cells per cubic millimeter (interquartile range, 375 to 662). A total of 82 HIV-1 infections occurred in seronegative participants during the study, 17 in the TDF group (incidence, 0.65 per 100 person-years), 13 in the TDF-FTC group (incidence, 0.50 per 100 person-years), and 52 in the placebo group (incidence, 1.99 per 100 person-years), indicating a relative reduction of 67% in the incidence of HIV-1 with TDF (95% confidence interval [CI], 44 to 81; P<0.001) and of 75% with TDF-FTC (95% CI, 55 to 87; P<0.001). Protective effects of TDF-FTC and TDF alone against HIV-1 were not significantly different (P=0.23), and both study medications significantly reduced the HIV-1 incidence among both men and women. The rate of serious adverse events was similar across the study groups. Eight participants receiving active treatment were found to have been infected with HIV-1 at baseline, and among these eight, antiretroviral resistance developed in two during the study. CONCLUSIONS: Oral TDF and TDF-FTC both protect against HIV-1 infection in heterosexual men and women. (Funded by the Bill and Melinda Gates Foundation; Partners PrEP ClinicalTrials.gov number, NCT00557245.). |
Antiretroviral preexposure prophylaxis for heterosexual HIV transmission in Botswana
Thigpen MC , Kebaabetswe PM , Paxton LA , Smith DK , Rose CE , Segolodi TM , Henderson FL , Pathak SR , Soud FA , Chillag KL , Mutanhaurwa R , Chirwa LI , Kasonde M , Abebe D , Buliva E , Gvetadze RJ , Johnson S , Sukalac T , Thomas VT , Hart C , Johnson JA , Malotte CK , Hendrix CW , Brooks JT . N Engl J Med 2012 367 (5) 423-34 BACKGROUND: Preexposure prophylaxis with antiretroviral agents has been shown to reduce the transmission of human immunodeficiency virus (HIV) among men who have sex with men; however, the efficacy among heterosexuals is uncertain. METHODS: We randomly assigned HIV-seronegative men and women to receive either tenofovir disoproxil fumarate and emtricitabine (TDF-FTC) or matching placebo once daily. Monthly study visits were scheduled, and participants received a comprehensive package of prevention services, including HIV testing, counseling on adherence to medication, management of sexually transmitted infections, monitoring for adverse events, and individualized counseling on risk reduction; bone mineral density testing was performed semiannually in a subgroup of participants. RESULTS: A total of 1219 men and women underwent randomization (45.7% women) and were followed for 1563 person-years (median, 1.1 years; maximum, 3.7 years). Because of low retention and logistic limitations, we concluded the study early and followed enrolled participants through an orderly study closure rather than expanding enrollment. The TDF-FTC group had higher rates of nausea (18.5% vs. 7.1%, P<0.001), vomiting (11.3% vs. 7.1%, P=0.008), and dizziness (15.1% vs. 11.0%, P=0.03) than the placebo group, but the rates of serious adverse events were similar (P=0.90). Participants who received TDF-FTC, as compared with those who received placebo, had a significant decline in bone mineral density. K65R, M184V, and A62V resistance mutations developed in 1 participant in the TDF-FTC group who had had an unrecognized acute HIV infection at enrollment. In a modified intention-to-treat analysis that included the 33 participants who became infected during the study (9 in the TDF-FTC group and 24 in the placebo group; 1.2 and 3.1 infections per 100 person-years, respectively), the efficacy of TDF-FTC was 62.2% (95% confidence interval, 21.5 to 83.4; P=0.03). CONCLUSIONS: Daily TDF-FTC prophylaxis prevented HIV infection in sexually active heterosexual adults. The long-term safety of daily TDF-FTC prophylaxis, including the effect on bone mineral density, remains unknown. (Funded by the Centers for Disease Control and Prevention and the National Institutes of Health; TDF2 ClinicalTrials.gov number, NCT00448669 .). |
Quantification of the spatial distribution of rectally applied surrogates for microbicide and semen in colon with SPECT and magnetic resonance imaging
Cao YJ , Caffo BS , Fuchs EJ , Lee LA , Du Y , Li L , Bakshi RP , Macura K , Khan WA , Wahl RL , Grohskopf LA , Hendrix CW . Br J Clin Pharmacol 2012 74 (6) 1013-22 AIMS: We sought to quantitatively describe the distribution of rectally administered gels and seminal fluid surrogates using novel concentration-distance parameters that could be repeated over time. These methods are needed to rationally develop rectal microbicides to target and prevent HIV infection. METHODS: Eight subjects were dosed rectally with radiolabeled and gadolinium-labeled gels to simulate microbicide gel and seminal fluid. Rectal doses were given with and without simulated receptive anal intercourse. Twenty-four hour distribution was assessed with indirect single photon emission computed tomography (SPECT)/computed tomography (CT) and magnetic resonance (MR) imaging, and direct assessment via sigmoidoscopic brushes. Concentration-distance curves were generated using an algorithm for fitting SPECT data in 3-dimensions. Three novel concentration-distance parameters were defined to quantitatively describe the distribution of radiolabels: maximal distance (D(max) ), distance at maximal concentration (D(Cmax) ), mean residence distance (D(ave) ). RESULTS: The SPECT/CT distribution of microbicide and semen surrogates was similar. Between 1 hour and 24 hours post-dose, the surrogates migrated retrograde in all three parameters (relative to coccygeal level; geometric mean [95% confidence interval]): maximal distance (D(max) ), 10 cm (8.6-12) to 18 cm (13-26); distance at maximal concentration (D(Cmax) ), 3.8 cm (2.7-5.3) to 4.2 cm (2.8-6.3); mean residence distance (D(ave) ), 4.3 cm (3.5-5.1) to7.6 cm (5.3-11). Sigmoidoscopy and MRI correlated only roughly with SPECT/CT. CONCLUSIONS: Rectal microbicide surrogates migrated retrograde during the 24 hours following dosing. Spatial kinetic parameters estimated using three dimensional curve fitting of distribution data should prove useful for evaluating rectal formulations of drugs for HIV prevention and other indications. (2012 (c) The Authors. British Journal of Clinical Pharmacology (c) 2012 The British Pharmacological Society.) |
CFTR mutation analysis and haplotype associations in CF patients.
Cordovado SK , Hendrix M , Greene CN , Mochal S , Earley MC , Farrell PM , Kharrazi M , Hannon WH , Mueller PW . Mol Genet Metab 2012 105 (2) 249-54 Most newborn screening (NBS) laboratories use second-tier molecular tests for cystic fibrosis (CF) using dried blood spots (DBS). The Centers for Disease Control and Prevention's NBS Quality Assurance Program offers proficiency testing (PT) in DBS for CF transmembrane conductance regulator (CFTR) gene mutation detection. Extensive molecular characterization on 76 CF patients, family members or screen positive newborns was performed for quality assurance. The coding, regulatory regions and portions of all introns were sequenced and large insertions/deletions were characterized as well as two intronic di-nucleotide microsatellites. For CF patient samples, at least two mutations were identified/verified and four specimens contained three likely CF-associated mutations. Thirty-four sequence variations in 152 chromosomes were identified, five of which were not previously reported. Twenty-seven of these variants were used to predict haplotypes from the major haplotype block defined by HapMap data that spans the promoter through intron 19. Chromosomes containing the F508del (p.Phe508del), G542X (p.Gly542X) and N1303K (p.Asn1303Lys) mutations shared a common haplotype subgroup, consistent with a common ancient European founder. Understanding the haplotype background of CF-associated mutations in the U.S. population provides a framework for future phenotype/genotype studies and will assist in determining a likely cis/trans phase of the mutations without need for parent studies. |
Proficiency testing of human leukocyte antigen-DR and human leukocyte antigen-DQ genetic risk assessment for type 1 diabetes using dried blood spots
Dantonio P , Meredith-Molloy N , Hagopian WA , She JX , Akolkar B , Cordovado SK , Hendrix M , Henderson LO , Hannon WH , Vogt RF . J Diabetes Sci Technol 2010 4 (4) 929-941 BACKGROUND: The plurality of genetic risk for developing type 1 diabetes mellitus (T1DM) lies within the genes that code for the human leukocyte antigens (HLAs). Many T1DM studies use HLA genetic risk assessment to identify higher risk individuals, and they often conduct these tests on dried blood spots (DBSs) like those used for newborn bloodspot screening. One such study is The Environmental Determinants of Diabetes in the Young (TEDDY), a long-term prospective study of environmental risk factors. To provide quality assurance for T1DM studies that employ HLA genetic risk assessment, the Centers for Disease Control and Prevention (CDC) conducts both a voluntary quarterly proficiency testing (VQPT) program available to any laboratory and a mandatory annual proficiency testing (PT) challenge for TEDDY laboratories. METHODS: Whole blood and DBS samples with a wide range of validated HLA-DR and HLA-DQ genotypes were sent to the participating laboratories. Results were evaluated on the basis of both the reported haplotypes and the HLA genetic risk assessment. RESULTS: Of the reported results from 24 panels sent out over six years in the VQPT, 94.7% (857/905) were correctly identified with respect to the relevant HLA-DR or HLA-DQ alleles, and 96.4% (241/250) were correctly categorized for risk assessment. Significant improvement was seen over the duration of this program, usually reaching 100% correct categorization during the last three years. Of 1154 reported results in four TEDDY PT challenges, 1153 (99.9%) were correctly identified for TEDDY eligibility. CONCLUSIONS: The different analytical methods used by T1DM research centers all provided accurate (>99%) results for genetic risk assessment. The two CDC PT programs documented the validity of the various approaches to screening and contributed to overall quality assurance. |
Novel human leukocyte antigen class I and class II alleles identified by sequence-based typing in the Genetics of Kidneys in Diabetes (GoKinD) study population
Cordovado SK , Hancock LN , Hendrix M , Greene CN , Mueller PW . Hum Immunol 2009 70 (9) 747-9 Nine novel HLA class I and class II alleles were identified by sequence-based typing (SBT) in Caucasian participants from the Genetics of Kidneys in Diabetes (GoKinD) study. All novel alleles were single nucleotide substitutions. Seven alleles resulted in an amino acid change and two alleles were silent substitutions. The new alleles are as follows: five HLA-A alleles (*0132, *020121, *0344, *030107, *2507), one HLA-C allele (*0619), two HLA-DQB1 alleles (*0204, *0318), and one HLA-DPB1 allele (*1802). Eight of these new alleles were identified in participants with type 1 diabetes, three of whom also had diabetic nephropathy, and one new allele was identified in an unaffected parent of a participant with type 1 diabetes. All new alleles were isolated and characterized by use of single allele amplification (SAA) SBT; the new alleles were confirmed by sequence-specific primer (SSP) amplification. |
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