Microbiology/Infectious Diseases

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12503/21764

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IDENTIFYING HIGH RESPONDER POPULATIONS TO CROFELEMER FOR TREATMENT OF NONINFECTIOUS DIARRHEA IN HIV+ INDIVIDUALS
(2014-03) Clay, Patrick G.
Background: Diarrhea remains a significant burden in some HIV+ individuals. Crofelemer is a first-in-class, minimally absorbed, botanically derived drug indicated for symptomatic relief of noninfectious diarrhea in adults with HIV/AIDS taking antiretroviral therapy. This analysis examined the efficacy of crofelemer 125 mg BID in specific subpopulations. Methods: In a 4-week, phase 3, randomized, double-blind, placebo-controlled trial in HIV+ adults receiving antiretroviral therapy, crofelemer 125 mg BID (n = 136) was compared with placebo (n = 138) for reducing noninfectious diarrhea. The primary efficacy endpoint (≤2 watery stools/wk for ≥2 of 4 weeks) was examined in subgroups that differed according to demographic (sex, age, race, time since HIV diagnosis, and duration of diarrhea) and baseline characteristics (severity of diarrhea, prior antidiarrheal medication [ADM] use, stool consistency, viral load, CD4+ cell count, and use of protease inhibitors). Results: At baseline, patients experienced (range of means) 18.9-21.0 watery stools/week, and investigators attributed diarrhea most commonly (75%) to antiretroviral therapy (ritonavir-containing agents, 34%-36%; efavirenz/tenofovir/emtricitabine, 15%-22%) or HIV enteropathy (24%). Across all subgroups considered, treatment effects favored crofelemer. Pronounced treatment differences (crofelemer – placebo) were observed for patients with prior use of ≥2 ADMs (+28%; P 2 watery stools/day (+10%; P = 0.03), diarrhea duration [greater than] 2 years (+11%; P = 0.03), and use of protease inhibitors (+11%; P = 0.021). Conclusions: These findings suggest that the crofelemer antidiarrheal effect is robust and generalizable across patient subpopulations. Purpose (a): To determine which patients with HIV/AIDS are most likely to respond to treatment with crofelemer 125 mg twice daily. Methods (b): Patients and Study Design: HIV+ adults taking a stable ART regimen for ≥4 weeks, with a history of diarrhea (persistently loose stools despite regular antidiarrheal medication use or ≥1 watery bowel movement per day without regular antidiarrheal medication use for ≥1 month). Exclusion criteria included CD4+ cell count/μL and positive gastrointestinal biopsy, culture, or stool test for infectious agents in the previous 4 months. Randomized, double-blind, phase 3 trial of crofelemer 125 mg or placebo administered twice daily for 4 weeks. Assessments: Primary efficacy measure: percentage of patients achieving clinical response, defined as ≤2 watery stools per week for ≥2 of 4 weeks of treatment. Assessment of efficacy was based on patient diaries, which recorded symptoms of diarrhea (eg, stool consistency, stool frequency), adherence to study drug and ART, and use of antidiarrheal and prohibited medications; results were entered daily using an interactive voice response system. Stool consistency score was computed using the mean of all reported stool scores for 1 day; stools were scored using a scale ranging from 1 to 5 (1 = very hard; 5 = watery). Statistical Analyses: Efficacy was assessed in the intention-to-treat population composed of all randomized patients receiving ≥1 dose of study drug (1-sided for primary efficacy analysis, based on technique described by Posch et al13; 2-sided for subgroup analyses). Fisher’s exact test was used for comparisons between crofelemer and placebo for subgroup analyzed. Subgroup analyses were not corrected for multiple comparisons. Results (c): Patient Population: Demographic and baseline characteristics were similar between the 2 groups. Patients in the crofelemer and placebo treatment arms were of similar age (mean, 45 vs 44.8 y), sex (male, 84.6% vs 84.1%), and race/ethnicity (white, 39.0% vs 42.0%; black, 37.5% vs 38.4%; Hispanic, 22.8% vs 18.1%; American Indian/Alaskan Native, 0.7% vs 0%; other, 0% vs 1.5%). Patients in both groups averaged >18.9 watery bowel movements per week. Historical use of antidiarrheal medication was common, reported by 79 patients (58%) receiving crofelemer 125 mg and 83 patients (60%) receiving placebo. Loperamide-containing agents were historically used by 53 (39%) and 60 (43%) patients treated with crofelemer and placebo, respectively. Although not permitted during the 4 weeks of treatment, concomitant use of antidiarrheal medications (eg, loperamide, diphenoxylate /atropine, bismuth subsalicylate) were reported by 1.1% and 4.0% of patients receiving crofelemer or placebo, respectively. Efficacy: A significantly greater percentage of patients achieved clinical response during treatment with crofelemer 125 mg twice daily versus placebo (P = 0.0096; Figure 2). Conclusions (d): Subgroup analyses confirm crofelemer 125 mg twice daily provides robust clinical response across multiple patient subpopulations. Crofelemer was particularly effective in patients with factors associated with severe diarrhea, consistent with its antisecretory effects on intestinal chloride channels.
C. DIFFICILE: A CHARACTERIZATION OF VIRULENCE FACTORS AND GROWTH BETWEEN EPIDEMIC VERSUS NON-EPIDEMIC STRAINS
(2014-03) Vitucci, John C.; Pulse, Mark; Simecka, Jerry
Clostridium difficile (C. difficile) is a spore-forming, gram positive bacterium found naturally within a human’s intestinal flora, as well as in the environment. This organism is safe in small numbers as a part of the natural intestinal flora, but can pose problems when broad-spectrum antibiotics, such as clindamycin, kill off other natural flora. Presently, there are two different, over-arching categories of C. difficile, toxigenic strains, which cause disease, and non-toxigenic, non-disease causing strains. These toxigenic strains can be broken into sub-categories: non-epidemic and epidemic. These labels are given based on the prevalence of an isotype in a geographical location. The most prevalent isotype is classified as epidemic and the less prevalent isotypes are classified as non-epidemic. Previous research has produced in vitro studies of epidemic and non-epidemic C. difficile strains, and there have been no conclusive patterns determined from these studies to determine the difference of virulence factors between strains. Therefore, is there a difference with the growth characteristics and virulence factors contributing to the severity of infection between epidemic and non-epidemic C. difficile strains both in vitro and in vivo? In vitro characterization of five non-epidemic and five epidemic strains, starting with virulence factor characterization of viable and germinated cell counts, as well as Toxin A and B production quantification were found to be statistically different between strains. In contrast, observed differences were slight and suggest that, in vitro, C. difficile can be treated as a group from an non-epidemic versus epidemic standpoint. The next group of in vitro studies including Growth Curves, Minimum Inhibitory Concentration studies, and Inhibition Curves also showed little observed differences between the non-epidemic and epidemic strains continuing to support the observations from the first set of studies stating that: C. difficile can be characterized and treated as a group instead of individual strains during infection. Future in vivo studies will help to determine if these trends between non-epidemic and epidemic strains will remain viable when the environment contains additional factors during infection, such as p.H. shifts, nutrition influx, and treatment with antibiotics within a system. Purpose (a): Clostridium difficile (C. difficile) is a spore-forming, gram positive bacterium found naturally within a human’s intestinal flora capable of causing severe disease. Other research has focused on in vitro studies of epidemic and non-epidemic C. difficile strains, and these studies concluded no conclusive patterns between the difference in virulence factors between the individual strains. Therefore, an important question to ask is: for C. difficile, is there a difference with the growth characteristics and virulence factors contributing to the severity of infection between epidemic and non-epidemic C. difficile strains both in vitro and in vivo? Methods (b): For the in vitro studies, there are multiple protocols used including, viable cell counts, spore isolation and germinated cell counts, Toxin A or B ELISA assays, growth and inhibition curves, as well as minimum inhibitory concentration (MIC) determination. In vivo UNTHSC Pre-Clinical Services 21-day Recurrence Hamster Model and Next-Gen Sequencing for microbiome research will be utilized. Results (c): When non-epidemic and epidemic C. difficile strains were characterized for major virulence factors, statistically significant differences for both intrastrain and interstrain comparisons were observed. Growth curve data showed consistent growth patterns between the strains. MIC results were consistent between strains, with no more than a 100-fold difference between the MIC of any one drug for all the strains tested. Inhibition curve results also showed minimal variation between the different non-epidemic and epidemic strain behavior when growth was tested against metronidazole, moxifloxacin, and vancomycin. Conclusions (d): During characterization in vitro, between five non-epidemic and five epidemic strain’s virulence factors, the differences in results are small, yet statistically significant. Though statistically different, observed differences are minimal and not believed to affect the individual strain's overall virulence. Therefore, it is concluded, in vitro, different strains of C. difficile have similar growth patterns and have similar virulence characteristics as a group. When further study was conducted to compare growth patterns over 24-hours, MIC’s concentrations, and Inhibition Curves, interstrain comparisons once again showed small observed differences. The overall trends in antibiotic susceptibility and growth patterns when the media was without, and supplemented with, antibiotics were seen to be similar. This continues to support that C. difficile can be treated, in vitro, as a group, independent of the labels non-epidemic and epidemic.
CROFELEMER FOR HIV-ASSOCIATED DIARRHEA: SUSTAINED EFFICACY, SAFETY, AND ADHERENCE DURING A 6-MONTH RANDOMIZED, PLACEBO-CONTROLLED TRIAL
(2014-03) Clay, Patrick G.
Combination antiretroviral therapy (cART) in HIV+ individuals has increased life expectancy; however, increased ART exposure is also associated with adverse effects that can negatively impact overall health, work productivity, and healthcare resource utilization. Diarrhea, an adverse event (AE) of ART, remains a substantial burden associated with reduced quality of life and may result in ART nonadherence or treatment failure. Reported prevalence of diarrhea in the community is up to 28% of patients receiving cART. Crofelemer, extracted from the stem bark latex of the Croton lechleri tree, is a minimally absorbed, first-in-class antidiarrheal agent indicated for the symptomatic relief of noninfectious diarrhea in adults with HIV/AIDS receiving ART. Crofelemer inhibits chloride ion (Cl–) secretion and accompanying high-volume water loss in secretory diarrhea via dual inhibition of cystic fibrosis transmembrane conductance regulator and calcium-activated Cl– channels in the intestinal epithelium. Purpose (a): To assess patient adherence to and efficacy and safety of crofelemer 125 mg twice daily for up to 6 months. Methods (b): Randomized, phase 3, double-blind, placebo-controlled, 2-stage trial (Figure 1). The optimal crofelemer (Fulyzaq™, Salix Pharmaceuticals, Inc., Raleigh, NC, USA) dose (125, 250, or 500 mg twice daily) was determined in stage 1. Based on the stage 1 interim efficacy and safety analysis, crofelemer 125 mg twice daily was selected as the optimal dose and was evaluated in additional patients in stage 2; data for crofelemer 125 mg twice daily were combined (stage 1 and 2). Primary efficacy measure: percentage of patients achieving clinical response, defined as ≤2 watery stools per week for ≥2 of 4 weeks during the placebo-controlled phase (1-sided analysis). Results (c): Demographic and baseline characteristics were similar between crofelemer 125 mg twice daily (n = 136) and placebo (n = 138) groups (Table 1); patients had a mean of 2.7 to 3.0 watery stools per day (ie, >18 watery stools per week). Primary measure: A significantly larger percentage of patients treated with crofelemer achieved clinical response compared with placebo (17.6% vs 8.0%; P < 0.01). Continued and sustained improvement in weekly clinical response and a mean improvement from baseline in diarrhea symptoms was observed in patients who continued to receive crofelemer 125 mg twice daily during the placebo-free phase. Conclusions (d): Crofelemer 125 mg twice daily was efficacious and well tolerated, and improvements in noninfectious diarrhea symptoms appeared to be durable for at least 6 months in an HIV+ population receiving stable cART. Treatment of diarrhea in HIV+ individuals may provide several important benefits, such as improvement in cART adherence.
DEEP SEQUENCING OF CULTIVATION-NEGATIVE BRONCHOAVEOLAR LAVAGE SAMPLES FROM MECHANICALLY VENTILATED TRAUMA PATIENTS REVEALS DEFICITS IN TRADITIONAL CLINICAL PROTOCOLS
(2014-03) Smith, Ashley D.; Zhang, Yan; DeSpain, Kevin; Huebinger, Ryan M.; Allen, Michael S.
Patients undergoing mechanical ventilation are at risk for infections such as ventilator-acquired pneumonia. Standard clinical protocols call for pathogen screening on culture plates which can only detect a limited number of bacteria. We sampled the lungs of mechanically ventilated trauma patients, and by using molecular-based deep sequencing techniques we found several potentially pathogenic bacteria in samples that traditional techniques labeled as “no growth” or normal “respiratory tract flora." Purpose (a): Bronchoaveolar lavage (BAL) is a method of screening mechanically ventilated patients for potentially pathogenic microogranisms. Traditional culture-based techniques used in clinical laboratories detect a limited number of known bacteria; consequently, some samples may be falsely reported as “cultivation-negative” or possessing only “normal respiratory tract flora.” To ascertain the potential for false negative results, we performed next generation DNA sequencing on BAL samples previously determined to be “cultivation negative” or “respiratory tract flora” by standard plate methods. Methods (b): Nine samples were taken from mechanically ventilated trauma patients in the Surgical Intensive Care Unit (SICU) subjected to BAL as part of the standard of care. DNA was extracted from the samples and the 16S rRNA subunit was amplified and sequenced using the Ion Torrent Personal Genome Machine. Sequences were analyzed using Mothur data-analysis pipeline to identify the appropriate taxonomic designation. Results (c): Results indicated that the majority (>77%) were dominated by a single organism. One third (3/9) of the samples analyzed were dominated by Neisseria spp. Other potential pathogens found to be dominant within the BAL samples included Streptococcus, Haemophilus, Aeromonas, and Rothia spp. Contamination from the oral cavity were also likely in two samples as evidenced by the identification of Porphyromonas and Prevotella spp. Conclusions (d): Our study demonstrates potential benefits of using next-generation sequencing to supplement the current culture-dependent clinical diagnostic methods. The knowledge gained from analyzing the lung microbiome of “culture-negative” and “respiratory tract flora” may be an important tool for identifying difficult to cultivate species associated with lung infections in mechanically ventilated patients.
HIV-1 TAT INDUCED LYSOSOMAL EXOCYTOSIS IN ASTROCYTES AND ITS CONTRIBUTIONS TO TAT NEUROTOXICITY
(2014-03) Fan, Yan; He, Johnny
Purpose (a): HIV-1 Tat protein is considered to be the critical reason in the processing of HIV-associated neuropathogenesis. Our previous studies demonstrates that HIV-1 Tat expression leads to ER stress in astrocytes through GFAP aggregation and suggest that disruption of ER homeostasis, i.e., ER stress may be involved in HIV-associated neuropathogenesis. But what the neurotoxic factor is in this indirect astrocyte-mediated Tat neurotoxicity system is still unknown. In this study, we take advantage of our Tat-inducible transgenic mice, and proteomic analysis was performed to explore the neurotoxic factor in the astrocyte-mediated Tat neurotoxicity system. Methods (b): Brain-targeted inducible Tat transgenic and GFAP knockout mice were used in the study. Primary astrocytes and neurons cultures were prepared from mouse embryos. U373 cells and primary astrocytes and were either transfected with pTat.Myc or treated with doxycycline to induce Tat expression. Cells were prepared and analyzed for β–hexosaminidase activity by NAG assay after ionomycin mediated Ca2+ influx. Culture supernatants were collected for immunodepletion and analyzed for their neurotoxicity toward primary mouse or human neurons using MTT assay. TIRF microscopy is utilized to visualize lysosome exocytosis events. Results (c): Base on the protein sequencing and pathway analysis, we proposed that HIV-1 Tat induces lysosomal exocytosis in astrocytes. Then, NAG assay and TIRF microscopy provide consistent evidences that verified our hypothesis. Moreover, we attested that inhibition of Tat induced lysosomal exocytosis in astrocytes by vaculin-1 can abolish Tat induced neuron death. More interestingly, we observed that Tat induced lysosomal exocytosis and neuron death only appears in astrocytes but not in other cell types, such as 293T and Huh 7.5.1 cells. Further more, we proved that GFAP plays a critical role in Tat induced lysosomal exocytosis and neuron death. Conclusions (d): Taken together, these results demonstrate that HIV-1 Tat induces lysosomal exocytosis and hydrolytic enzymes contained within lysosome are suggested to contribute to neuronal death, which is a novel insight into astrocytes-mediated Tat neurotoxicity.
IMPLICATIONS OF ASTROCYTIC NRF2-ARE SIGNALING PATHWAY IN METHAMPHETAMINE AND HIV-1gp120 INDUCED OXIDATIVE STRESS
(2014-03) Shelake, Sagar; Ghorpade, Anuja
Despite the advent of the antiretroviral therapy, HIV-1 associated neurocognitive disorders (HAND) continue to be a significant issue for HIV-1 infected patients. HIV-1 infection of CNS combined with Methamphetamine (METH) abuse causes overall increase in oxidative stress in astrocyte. In HAND patients, oxidative stress induced apoptosis in astrocyte compromises the normal physiology and function of CNS. NF-E2–related factor 2 (Nrf2) transcription factor plays vital role in cellular protective response against oxidative stress due to environmental agents such as electrophiles, drug abuse, smoking, radiation. Although HIV-1 gp120and METH have been implicated in the pathogenesis of HAND, little is known about their combined effect on the regulation of Nrf2 in human astrocytes. In this study, we investigated the combinatorial effect of gp120 and METH on Nrf2-ARE signaling pathway in primary human fetal astrocytes. Astrocytes were treated with METH and gp120 followed by immunocytochemistry analysis. The oxidative stress and apoptosis was detected by protein carbonylation and DNA fragmentation, respectively. The levels of phospho-Nrf2 and Nrf2 were analyzed by western blot. Repeated treatment of METH and gp120 induced the reactive astrocyte phenotype as observed by GFAP immunostaining. METH and gp120 significantly increased oxidative stress and apoptosis. Further investigation revealed that METH and gp120 significantly increased Nrf2 phosphorylation and nuclear translocation in a time-dependent manner. Taken together, these results suggest the involvement of Nrf2-ARE signaling pathway as a protective response to METH- and gp120- induced oxidative stress in human astrocytes. Purpose (a): Despite the advent of the antiretroviral therapy, HIV-1 associated neurocognitive disorders (HAND) continue to be a significant issue for HIV-1 infected patients. HIV-1 infection of CNS combined with Methamphetamine (METH) abuse causes overall increase in oxidative stress in astrocyte. In HAND patients, oxidative stress induced apoptosis in astrocyte compromises the normal physiology and function of CNS. NF-E2–related factor 2 (Nrf2) transcription factor plays vital role in cellular protective response against oxidative stress due to environmental agents such as electrophiles, drug abuse, smoking, radiation. Although HIV-1 gp120and METH have been implicated in the pathogenesis of HAND, little is known about their combined effect on the regulation of Nrf2 in human astrocytes. In this study, we investigated the combinatorial effect of gp120 and METH on Nrf2-ARE signaling pathway in primary human fetal astrocytes. Methods (b): Astrocytes were treated with METH and gp120 followed by immunocytochemistry analysis. The oxidative stress and apoptosis was detected by protein carbonylation and DNA fragmentation, respectively. The levels of phospho-Nrf2 and Nrf2 were analyzed by western blot. Results (c): Repeated treatment of METH and gp120 induced the reactive astrocyte phenotype as observed by GFAP immunostaining. METH and gp120 significantly increased oxidative stress and apoptosis. Further investigation revealed that METH and gp120 significantly increased Nrf2 phosphorylation and nuclear translocation in a time-dependent manner. Conclusions (d): Taken together, these results suggest the involvement of Nrf2-ARE signaling pathway as a protective response to METH- and gp120- induced oxidative stress in human astrocytes.
ELUCIDATING THE DIVERSITY OF MICROBIAL RETTING COMMUNITIES ON HIBISCUS CANNABINUS USING NEXT-GENERATION SEQUENCING
(2014-03) Visi, David K.; Allen, Michael S.
Purpose (a): Global environmental concerns have led to a growing interest in renewable resources such as plant-based fibers. Beyond textiles and cordage, plant fibers have the potential for incorporation into renewable, bio-based composite materials for the building and manufacturing sectors. Successful commercialization of fiber production requires optimization of fiber extraction. Retting is the traditional method of fiber extraction, whereby endogenous microorganisms break down heteropolysaccharides to release fiber bundles. Previous studies have analyzed the retting solution for its bacterial constituents, but none have followed changes in the microbial community through the retting process. This research aims to track the bacterial components of the retting community through time, and determine the effects of bacterial augmentation with isolated pectinolytic bacteria using next generation sequencing of 16S rRNA gene amplicons. Methods (b): Batch C1 included plant material and an inoculum of pond water represented a “traditional” retting environment, while C2 contained autoclaved pond water to represent the endogenous microorganisms associated with the plant material. Experimental batch E1 included the addition of three pectinolytic bacterial isolates: Bacillus DP1, Paenibacillus DP2, and Bacillus K1. Total DNA was extracted from the surface-adhering biofilm bacteria and used for PCR with full-length 16S primers 27F and 1492R. Amplification products were used as templates for a nested PCR with primers 786F and 939R targeting variable region 5 of the 16S molecule. The nested 16S rRNA amplicons were then sequenced on the next-generation Ion Torrent PGM platform. Results (c): The E1 environment showed a marked increase in phylum Firmicutes (55 to 94%), while phylum Proteobacteria showed a progressive decrease from Day 1 to 4 (36% to 5%). This was correlated with easy separation of fibers by mechanical movement. At a finer taxonomic level, E1 showed a rapid loss of inoculated Bacillus species DP1 and K1, and a more gradual loss of the family Paenibacillaceae 1 (P. DP2) as the time course progressed. In contrast, C1 was co-dominated by phyla Firmicutes and Proteobacteria, while C2 was composed in large part by the phylum Bacteroidetes. Additionally, comparison of the microbial communities under the different conditions revealed differences in diversity and composition at day 4 time points between the three conditions. Conclusions (d): Introduction of pectinolytic bacteria into the batch reactions increased production rate and increased fiber quality. Introduction of Paenibacillus DP2 is likely the driving force behind the community shifts detected in E1, which warrants further study to determine the mechanism of action. The findings confirmed previous studies that suggest a gradual replacement of aerobic organisms to an environment that is dominated by strict anaerobes. Moreover, the efforts shed light on conditions and mechanisms for the manipulation of microbiomes. These approaches may have relevance to the treatment of dysbiosis in the gut flora in humans and the treatment of related diseases.
SAFETY AND TOLERABILITY OF CROFELEMER 125 MG TWICE DAILY IN THE TREATMENT OF NONINFECTIOUS DIARRHEA IN HIV-SEROPOSITIVE PATIENTS ON ANTIRETROVIRAL THERAPY: RESULTS FROM A PHASE 3, 48-WEEK OPEN-LABEL STUDY
(2014-03) Clay, Patrick G.
Diarrhea remains a substantial health concern in patients with HIV in the era of combination antiretroviral therapy (ART), despite the decline in opportunistic infectious diarrhea. For example, noninfectious diarrhea attributable to ART-related adverse events (AEs) has a reported prevalence in the community of up to 28% of patients with HIV who are receiving ART. Diarrhea in patients with HIV is commonly a leaky-flux or secretory diarrhea, which is characterized by increased secretion of chloride ions (Cl-) and subsequent sodium and water flow into the gastrointestinal lumen. Crofelemer (Fulyzaq™, Salix Pharmaceuticals, Inc., Raleigh, NC, USA) is a minimally absorbed, first-in-class, botanically derived drug indicated for the symptomatic relief of noninfectious diarrhea in adults with HIV. Following oral dosing of crofelemer, plasma concentrations of the drug were below the level of quantification in [greater than] 99% of patients with HIV and diarrhea. Crofelemer is a dual inhibitor of the cyclic adenosine monophosphate (cAMP)-stimulated cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channel and the calcium-activated Cl- channel (CACC). In a phase 3, double-blind, placebo-controlled trial (ADVENT), crofelemer 125 mg twice daily significantly reduced diarrhea in patients with HIV receiving ART compared with placebo, and the safety profile was comparable to placebo for up to 24 weeks. Purpose (a): To evaluate the long-term (up to 48 weeks) safety and tolerability of crofelemer 125 mg twice daily for the treatment of noninfectious diarrhea in patients with HIV. Methods (b): Phase 3, multicenter, open-label study of crofelemer 125 mg twice daily for up to 48 weeks. Results (c): Overall, 189 patients (75.6%) experienced ≥1 AE during this open-label study; the majority of AEs (90.5% of patients) were mild or moderate in intensity. The most commonly reported AEs were infection-related (eg, upper respiratory tract [16.8%], intestinal parasitic [12.4%], Giardia [8.0%]; none drug-related) or gastrointestinal-related (eg, nausea [5.6%], constipation [5.6%]) –Most patients (10 of 14 [71.4%]) reporting a constipation AE also used ADMs during the study. Only 9 (3.6%) patients reported diarrhea as an AE •AEs considered at least possibly related to study drug occurred in 9.2% of patients; the most commonly reported were constipation (3.6%), abdominal distension (2.0%), abdominal pain (1.2%), and flatulence (1.2%). No deaths occurred during the study; serious AEs occurred in 20 patients (8.0%), including infection in 10 patients; none were considered drug-related. Conclusions (d): Crofelemer 125 mg twice daily was well tolerated with a low incidence of AEs in HIV-seropositive patients with noninfectious diarrhea receiving ART, which is consistent with the minimal absorption of crofelemer. In this study, minimal clinical deterioration of immune status was observed for up to 48 weeks, suggestive of adherence to ART regimens and continued ART efficacy.
POPULATION PHARMACOKINETIC ANALYSIS DEMONSTRATES NO DRUG-DRUG INTERACTIONS BETWEEN CROFELEMER, A NOVEL TREATMENT FOR NONINFECTIOUS DIARRHEA IN HIV+ INDIVIDUALS, AND ANTIRETROVIRAL THERAPY
(2014-03) Clay, Patrick G.
Crofelemer, a minimally absorbed, botanically derived, first-in-class antidiarrheal agent, was approved by the US Food and Drug Administration in December 2012 at a dose of 125 mg twice daily for symptomatic relief of noninfectious diarrhea in adult patients with HIV/AIDS on ART. Secretory diarrhea, particularly noninfectious diarrhea, is associated with combination antiretroviral therapy (ART) therapy. It is characterized by increased secretion of chloride ions and the movement of sodium and water into the intestinal lumen as a result of cyclic adenosine monophosphate (cAMP)–stimulated cystic fibrosis transmembrane conductance regulator (CFTR) and calcium-activated chloride channel (CaCC) activation by HIV, ART, or bacterial enterotoxins. Crofelemer is a dual inhibitor of CFTR and CaCC in the intestinal epithelium. For patients with HIV/AIDS receiving combination ART, comorbidities requiring management or treatment with other therapies increase the potential for drug-drug interactions (DDI) with ART6; clinically significant DDI have been reported in 27% to 40% of patients with HIV/AIDS taking ART. Significant DDI with ART may be caused by induction or inhibition of major metabolic pathways, or by drug transporters, resulting in reductions in ART efficacy, safety, and tolerability. Purpose (a): To determine the potential for crofelemer to alter the pharmacokinetics (PK) of concomitantly administered ART agents in HIV+ patients in the ADVENT trial. Methods (b): HIV+ adults taking a stable ART regimen for ≥4 weeks, with a history of diarrhea (ie, persistently loose stools despite regular antidiarrheal medication use or ≥1 watery bowel movement per day without regular antidiarrheal use for ≥1 month) and CD4+ count ≥100 cells/μL. ADVENT is a randomized, double-blind, two-stage phase 3 trial (Figure 1) conducted from October 2007 to January 2011 Pharmacokinetic Assessments. A multiple-trough sampling design14 was used to assess population PK. Sample collection for PK assessments occurred at baseline, prior to dosing at randomization, at the end of the placebo-controlled phase (ie, week 4), and at the end of the study (ie, week 24). Immune status was evaluated by analysis of CD4+ cell count and HIV viral load. Crofelemer concentrations were assayed by validated high-performance liquid chromatography with fluorescence detection (Celerion, Lincoln, NE, USA); ART concentrations were assayed by Tandem Labs (Salt Lake City, UT, USA) and the University of North Carolina Clinical Pharmacology and Analytical Chemistry Core Facility (Chapel Hill, NC, USA). Results (c): More than 97.5% of patients in the PK population (n = 353) had received ≥ 3 combination ART regimens before the study. Patients received 126 different combinations of ART; the most frequently used combination ART was EFV, FTC, and TNF (n = 60). All 6 of the most common ARTs demonstrated marked exposure variability during the study (Figure 2). Week 4 and 24 ART steady-state trough drug concentrations in patients receiving crofelemer, regardless of crofelemer dose, were comparable with concentrations obtained during the crofelemer-free period (for example, TNF in Figure 3). Comparable results were demonstrated with RTV, FTC, 3TC, LPV, and EFV (Table 2). Crofelemer had no statistically significant effect on the PK of the 6 most commonly used ARTs in ADVENT, as assessed by the Bonferroni correction approach (Table 2). Administration of crofelemer had no negative impact on clinical immune parameters (HIV viral load and CD4+ cell counts) • In >96% of patients, crofelemer concentrations were below the limit of quantitation (50 ng/mL). Conclusions (d): Crofelemer had no significant effect on the PK of the most frequently-used ART evaluated in this study. Consistent with the absence of effects on ART PK, crofelemer did not adversely affect ART efficacy, based on HIV viral load or CD4+ cell counts. Crofelemer was not systemically absorbed to a significant extent.
ENVIRONMENTAL EXPOSURE RISK ASSESSMENT OF WEST NILE VIRUS IN CITY PARKS IN FORT WORTH, TEXAS
(2014-03) Tsecouras, Julie C.; Lee, Joon; Bennett, Brandon S.
We partnered with the City of Fort Worth to set up weekly mosquito traps to track West Nile Virus activity in three city parks. We set up traps overnight and picked them up the following morning. Mosquitoes from these traps were then brought back to our lab to be identified and tested for West Nile Virus. Purpose (a): In 2012, Dallas-Fort Worth experienced the largest epidemic of West Nile Virus (WNV) yet, little is known about risk of WNV exposure in park users, despite conceivably high degree of interaction between WNV reservoir avian hosts and vector mosquitoes. The purpose of this study was to assess environmental risk exposures of WNV in city parks and identify species composition of mosquitoes in Fort Worth. Methods (b): Three city parks with high public activities and/or vegetation were selected to assess environmental risk of exposure to WNV. The CDC light trap with CO2 was employed to collect mosquitoes, and proven or potential vector mosquitoes were tested for WNV infection by Reverse-Transcriptase Polymerase Chain Reaction. Results (c): A total of 502 mosquitoes of 4 proven or potential WNV vector species were tested. No mosquitoes had WNV infection. 18 mosquito species were collected. The average number of mosquitoes collected per trap night was 24.4. Conclusions (d): The low number of proven and potential WNV vectors and no evidence of WNV activities in the vector population indicate negligible risk of environmental exposure to WNV in the 2013 season. However, high variation of exposure risk to WNV warrants continuing effort to assess the exposure risk to WNV in environmental settings with high public activities like city parks.

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