The proteostasis interactomes of trafficking-deficient K V 11.1 variants associated with Long QT Syndrome and pharmacological chaperone rescue.

Introduction: The voltage gated potassium ion channel K V 11.1 plays a critical role in cardiac repolarization. Genetic variants that render Kv11.1 dysfunctional cause Long QT Syndrome (LQTS), which is associated with fatal arrhythmias. Approximately 90% of LQTS-associated variants cause intracellular protein transport (trafficking) dysfunction, which can be rescued by pharmacological chaperones like E-4031. Protein folding and trafficking decisions are regulated by chaperones, protein quality control factors, and trafficking machinery, comprising the cellular proteostasis network. Here, we test whether trafficking dysfunction is associated with alterations in the proteostasis network of pathogenic Kv11.1 variants, and whether pharmacological chaperones can normalize the proteostasis network of responsive variants. Methods: We used affinity-purification coupled with tandem mass tag-based quantitative mass spectrometry to assess protein interaction changes in human embryonic kidney (HEK293) cells expressing wild-type (WT) K V 11.1 or trafficking-deficient channel variants in the presence or absence of E-4031. Resultsa: We identified 573 core K V 11.1 protein interactors. Both variants K V 11.1-G601S and K V 11.1-G601S-G965* had significantly increased interactions with proteins responsible for folding, trafficking, and degradation compared to WT. We found that proteasomal degradation is a key component for K V 11.1 degradation and that the K V 11.1-G601S-G965* variant was more responsive to E-4031 treatment. This suggests a role in the C-terminal domain and the ER retention motif of K V 11.1 in regulating trafficking. Conclusion: Our report characterizes the proteostasis network of K V 11.1, two trafficking deficient K V 11.1 variants, and variants treated with a pharmacological chaperone. The identified protein interactions could be targeted therapeutically to improve K V 11.1 trafficking and treat Long QT Syndrome.

ent-Verticilide B1 Inhibits Type 2 Ryanodine Receptor Channels and is Antiarrhythmic in Casq2 -/- Mice.

Intracellular Ca2+ leak from cardiac ryanodine receptor (RyR2) is an established mechanism of sudden cardiac death (SCD), whereby dysregulated Ca2+ handling causes ventricular arrhythmias. We previously discovered the RyR2-selective inhibitor ent-(+)-verticilide (ent-1), a 24-membered cyclooligomeric depsipeptide that is the enantiomeric form of a natural product (nat-(-)-verticilide). Here, we examined its 18-membered ring-size oligomer (ent-verticilide B1; "ent-B1") in RyR2 single channel and [3H]ryanodine binding assays, and in Casq2 -/- cardiomyocytes and mice, a gene-targeted model of SCD. ent-B1 inhibited RyR2 single channels and RyR2-mediated spontaneous Ca2+ release in Casq2 -/- cardiomyocytes with sub-micromolar potency. ent-B1 was a partial RyR2 inhibitor, with maximal inhibitory efficacy of less than 50%. ent-B1 was stable in plasma, with a peak plasma concentration of 1460 ng/ml at 10 minutes and half-life of 45 minutes after intraperitoneal administration of 3 mg/kg in mice. In vivo, ent-B1 significantly reduced catecholamine-induced ventricular arrhythmias in Casq2 -/- mice in a dose-dependent manner. Hence, we have identified a novel chemical entity - ent-B1 - that preserves the mechanism of action of a hit compound and shows therapeutic efficacy. These findings strengthen RyR2 as an antiarrhythmic drug target and highlight the potential of investigating the mirror-image isomers of natural products to discover new therapeutics. SIGNIFICANCE STATEMENT: The cardiac ryanodine receptor (RyR2) is an untapped target in the stagnant field of antiarrhythmic drug development. We have confirmed RyR2 as an antiarrhythmic target in a mouse model of sudden cardiac death and shown the therapeutic efficacy of a second enantiomeric natural product.

ent -Verticilide B1 inhibits type 2 ryanodine receptor channels and is antiarrhythmic in Casq2-/- mice.

Ca 2+ leak from cardiac ryanodine receptor (RyR2) is an established mechanism of sudden cardiac death (SCD), whereby dysregulated Ca 2+ handling causes ventricular arrhythmias. We previously discovered the RyR2-selective inhibitor ent- (+)-verticilide ( ent -1), a 24-membered cyclooligomeric depsipeptide that is the enantiomeric form of a natural product ( nat -(-)-verticilide). Here, we examined its 18-membered ring-size oligomer ( ent -verticilide B1; " ent -B1") in single RyR2 channel assays, [ 3 H]ryanodine binding assays, and in Casq2 -/- cardiomyocytes and mice, a gene-targeted model of SCD. ent -B1 inhibited RyR2 single-channels and [ 3 H]ryanodine binding with low micromolar potency, and RyR2-mediated spontaneous Ca 2+ release in Casq2-/- cardiomyocytes with sub-micromolar potency. ent -B1 was a partial RyR2 inhibitor, with maximal inhibitory efficacy of less than 50%. ent -B1 was stable in plasma, with a peak plasma concentration of 1460 ng/ml at 10 min and half-life of 45 min after intraperitoneal administration of 3 mg/kg in mice. Both 3 mg/kg and 30 mg/kg ent -B1 significantly reduced catecholamine-induced ventricular arrhythmia in Casq2-/- mice. Hence, we have identified a novel chemical entity - ent -B1 - that preserves the mechanism of action of a hit compound and shows therapeutic efficacy. These findings strengthen RyR2 as an antiarrhythmic drug target and highlight the potential of investigating the mirror-image isomers of natural products to discover new therapeutics. Significance statement: The cardiac ryanodine receptor (RyR2) is an untapped target in the stagnant field of antiarrhythmic drug development. We have confirmed RyR2 as an antiarrhythmic target in a mouse model of sudden cardiac death and shown the therapeutic efficacy of a second enantiomeric natural product.

In Vivo Pharmacokinetic and Pharmacodynamic Properties of the Antiarrhythmic Molecule ent-Verticilide.

The unnatural verticilide enantiomer (ent-verticilide) is a selective and potent inhibitor of cardiac ryanodine receptor (RyR2) calcium release channels and exhibits antiarrhythmic activity in a murine model of catecholaminergic polymorphic ventricular tachycardia (CPVT). To determine verticilide's pharmacokinetic and pharmacodynamic properties in vivo, we developed a bioassay to measure nat- and ent-verticilide in murine plasma and correlated plasma concentrations with antiarrhythmic efficacy in a mouse model of CPVT. nat-Verticilide rapidly degraded in plasma in vitro, showing >95% degradation within 5 minutes, whereas ent-verticilide showed <1% degradation over 6 hours. Plasma was collected from mice following intraperitoneal administration of ent-verticilide at two doses (3 mg/kg, 30 mg/kg). Peak C max and area under the plasma-concentration time curve (AUC) scaled proportionally to dose, and the half-life was 6.9 hours for the 3-mg/kg dose and 6.4 hours for the 30-mg/kg dose. Antiarrhythmic efficacy was examined using a catecholamine challenge protocol at time points ranging from 5 to 1440 minutes after intraperitoneal dosing. ent-Verticilide inhibited ventricular arrhythmias as early as 7 minutes after administration in a concentration-dependent manner, with an estimated potency (IC50) of 266 ng/ml (312 nM) and an estimated maximum inhibitory effect of 93.5%. Unlike the US Food and Drug Administration-approved pan-RyR blocker dantrolene, the RyR2-selective blocker ent-verticilide (30 mg/kg) did not reduce skeletal muscle strength in vivo. We conclude that ent-verticilide has favorable pharmacokinetic properties and reduces ventricular arrhythmias with an estimated potency in the nanomolar range, warranting further drug development. SIGNIFICANCE STATEMENT: ent-Verticilide has therapeutic potential to treat cardiac arrhythmias, but little is known about its pharmacological profile in vivo. The primary purpose of this study is to determine the systemic exposure and pharmacokinetics of ent-verticilide in mice and estimate its efficacy and potency in vivo. The current work suggests ent-verticilide has favorable pharmacokinetic properties and reduces ventricular arrhythmias with an estimated potency in the nanomolar range, warranting further drug development.

Mechanistic Investigation of the Time-Dependent Aldehyde Oxidase Inhibitor Hydralazine.

The anti-hypertensive agent hydralazine is a time-dependent inhibitor of the cytosolic drug-metabolizing enzyme aldehyde oxidase (AO). Glutathione (GSH) was found to suppress the inhibition of AO by hydralazine in multiple enzyme sources (human liver and kidney cytosol, human liver S9, rat liver S9, and recombinant human AO) and with different AO substrates (zoniporide, O6 -benzylguanine, and dantrolene). Hydralazine-induced AO inactivation was unaffected when GSH was added to the incubation mixture after pre-incubation of hydralazine with AO (rather than during the pre-incubation), suggesting that GSH traps a hydralazine reactive intermediate prior to enzyme inactivation. Consistent with previous reports of 1-phthalazylmercapturic acid formation when hydralazine was incubated with N-acetylcysteine, we detected a metabolite producing an MS/MS spectrum consistent with a 1-phthalazyl-GSH conjugate. O6 -Benzylguanine, an AO substrate, did not protect against hydralazine-induced AO inactivation, implying that hydralazine does not compete with O6 -benzylguanine for binding to the AO active site. Catalase also failed to protect AO from hydralazine-induced inactivation, suggesting that hydrogen peroxide is not involved. However, an allosteric AO inhibitor (thioridazine) offered some protection, indicating a catalytic role for AO in the bioactivation of hydralazine. AO inhibition by phthalazine (a substrate and inhibitor of AO and a metabolite of hydralazine) was unaffected by the presence of GSH. GSH also prevented hydralazine from inhibiting the nitro-reduction of dantrolene by AO. Furthermore, the GSH-hydralazine combination stimulated dantrolene reduction. Phthalazine inhibited only oxidation reactions, not reduction of dantrolene. Together, these results support the hypothesis that hydralazine is converted to a reactive intermediate that inactivates AO. SIGNIFICANCE STATEMENT: These studies suggest that a reactive intermediate of hydralazine plays a primary role in the mechanism of aldehyde oxidase (AO) inactivation. Inactivation was attenuated by glutathione and unaffected by catalase. Phthalazine (hydralazine metabolite) inhibited AO regardless of the presence of glutathione; however, phthalazine inhibited only oxidation reactions, while hydralazine inhibited both oxidation and reduction reactions. This report advances our mechanistic understanding of hydralazine as an AO inhibitor and provides information to facilitate appropriate use of hydralazine when probing AO metabolism.

Anxiety Among Inpatients With Cancer: Findings From a Hospital-Based Cross-Sectional Study in Vietnam.

Anxiety, a condition which is commonly found in patients with cancer, has negative impacts on their quality of life and treatment outcome. This study aimed to determine the level of anxiety in patients with cancer and explore sociodemographic, disease-related, and hospital-related factors associated with anxiety in those patients. A cross-sectional study was conducted on 510 inpatients with cancer at Thanh Hoa Oncology Hospital, Vietnam. Data were collected from self-administered questionnaire forms on hospital depression anxiety-A, interviews with patients, and patient medical records. The univariate and multivariate linear regression analyses were performed using STATA ver. 14.0. Our finding that the patients' mean anxiety score (standard deviation) was 7.22 (3.8); 27.6% of the patients had an anxiety score between 8 and 10 points, and 15.5% had an anxiety score of ≥11 points. In the multivariate model, in more advanced stages of cancer, and patients with metastasis were more likely to have higher levels of anxiety than those who presented no sign of metastasis. The longer the patients had cancer, the less anxious they became. Lower levels of anxiety were observed in patients who stated that hospital facilities were adequate or had trust in health workers. Patients with cancer need to be provided with psychological support in the early stage of cancer detection and when metastases form. A strong patient-health-care provider relationship after diagnosis may help reduce distress among patients with cancer with higher levels of medical mistrust.

Rubella Vaccination Coverage Among Women of Childbearing Age in Vietnam.

Despite the availability of effective and safe rubella vaccines for women of childbearing age, prevention and control of congenital rubella syndrome in children remains challenging in Vietnam. In order to examine this issue, we conducted a cross-sectional study, examining the current coverage of rubella vaccination before pregnancy among 807 pregnant women and women with children under 12 months of age in urban and rural districts, Dong Da and Ba Vi, in Hanoi, Vietnam. In this population, we observed an alarming non-compliance rate with rubella vaccination before pregnancy in both localities. Among the 82.0% of participants who remained unvaccinated against this contagious viral infection, 95.8% of them were in Ba Vi district, compared to 68.0% in Dong Da district (p < 0.001). Besides the differences in age, number of children, education levels, primary occupations and monthly incomes among the participants between the two districts, other reasons for noncompliance with rubella vaccination includeddisinterest in rubella vaccination, the high cost and long distance to vaccination sites as well as unawareness of vaccination locations. In addition to addressing the unique socio-economicchallenges behind one's accessibility to vaccination services in urban and rural areas, our study supports a continued effort in ensuring proper access to and education about pre-pregnancy vaccines and vaccination among women of childbearing age in order to achieve and sustain sufficient immunization coverage of rubella and other vaccine-preventable diseases in both settings.

Hepatitis B Vaccination and Infection Prevalence Among Men Who Have Sex With Men Who Travel Internationally.

Among men who have sex with men traveling internationally, self-reported hepatitis B virus (HBV) vaccination prevalence was 77% and less prevalent among older men and those with HBV infection. The HBV infection prevalence was 25% and was associated with older age and HIV infection. Testing for chronic infection, universal vaccination, and treatment for populations with multiple risks is needed.

Reductions in access to HIV prevention and care services are associated with arrest and convictions in a global survey of men who have sex with men.

OBJECTIVES: Men who have sex with men (MSM) are disproportionately impacted by HIV. Criminalisation of homosexuality may impede access to HIV services. We evaluated the effect of the enforcement of laws criminalising homosexuality on access to services. METHODS: Using data from a 2012 global online survey that was published in a prior paper, we conducted a secondary analysis evaluating differences in perceived accessibility to health services (ie, 'how accessible are ____' services) between MSM who responded 'yes'/'no' to: 'have you ever been arrested or convicted for being gay/MSM?' RESULTS: Of the 4020 participants who completed the study and were included in the analysis, 8% reported ever being arrested or convicted under laws relevant to being MSM. Arrests and convictions were most common in sub-Saharan Africa (23.6% (58/246)), Eastern Europe/Central Asia (18.1% (123/680)), the Caribbean (15% (15/100)), Middle East/North Africa (13.2% (10/76)) and Latin America (9.7% (58/599)). Those arrested or convicted had significantly lower access to sexually transmitted infection treatment (adjusted OR (aOR)=0.81; 95% CI 0.67 to 0.97), condoms (aOR=0.77; 95% CI 0.61 to 0.99) and medical care (aOR=0.70; 95% CI 0.54 to 0.90), compared with other MSM, while accounting for clustering by country and adjusting for age, HIV status, education and country-level income. CONCLUSIONS: Arrests and convictions under laws relevant to being MSM have a strong negative association with access to HIV prevention and care services. Creating an enabling legal and policy environment, and increasing efforts to mitigate antihomosexuality stigma to ensure equitable access to HIV services are needed, along with decriminalisation of homosexuality, to effectively address the public health needs of this population.

Inequities in access to HIV prevention services for transgender men: results of a global survey of men who have sex with men.

INTRODUCTION: Free or low-cost HIV testing, condoms, and lubricants are foundational HIV prevention strategies, yet are often inaccessible for men who have sex with men (MSM). In the global context of stigma and poor healthcare access, transgender (trans) MSM may face additional barriers to HIV prevention services. Drawing on data from a global survey of MSM, we aimed to describe perceived access to prevention services among trans MSM, examine associations between stigma and access, and compare access between trans MSM and cisgender (non-transgender) MSM. METHODS: The 2014 Global Men's Health and Rights online survey was open to MSM (inclusive of trans MSM) from any country and available in seven languages. Baseline data (n=3857) were collected from July to October 2014. Among trans MSM, correlations were calculated between perceived service accessibility and anti-transgender violence, healthcare provider stigma, and discrimination. Using a nested matched-pair study design, trans MSM were matched 4:1 to cisgender MSM on age group, region, and HIV status, and conditional logistic regression models compared perceived access to prevention services by transgender status. RESULTS: About 3.4% of respondents were trans men, of whom 69 were included in the present analysis. The average trans MSM participant was 26 to 35 years old (56.5%); lived in western Europe, North America, or Oceania (75.4%); and reported being HIV-negative (98.6%). HIV testing, condoms, and lubricants were accessible for 43.5, 53.6, and 26.1% of trans MSM, respectively. Ever having been arrested or convicted due to being trans and higher exposure to healthcare provider stigma in the past six months were associated with less access to some prevention services. Compared to matched cisgender controls, trans MSM reported significantly lower odds of perceived access to HIV testing (OR=0.57, 95% CI=0.33, 0.98) and condom-compatible lubricants (OR=0.54, 95% CI=0.30, 0.98). CONCLUSIONS: This first look at access to HIV prevention services for trans MSM globally found that most reported inadequate access to basic prevention services and that they were less likely than cisgender MSM to have access to HIV testing and lubricants. Results indicate the need to enhance access to basic HIV prevention services for trans MSM, including MSM-specific services.

A simple method to elute cell-free HIV from dried blood spots improves their usefulness for monitoring therapy.

BACKGROUND: Dried blood spots (DBS) improve access to HIV viral load (VL) testing, but yield increased VL measurements compared to the plasma reference method because of cell-associated viral nucleic acid. In clinical settings, DBS methods may falsely categorize many patients as failing therapy. OBJECTIVES: Description of a simple method, free virus elution (FVE), to preferentially elute plasma-associated virus from DBS samples with phosphate-buffered saline, and an initial HIV VL performance comparison with standard DBS elution methods. STUDY DESIGN: The mechanism of action of FVE was studied with model DBS samples containing purified virus or washed HIV-containing cells, and with a DNA-specific HIV PCR. Using clinical samples, VL results from the new FVE method were compared to results from a dried fluid spot procedure (DFSP) protocol, which uses a guanidinium-based elution method, using plasma VL as the reference method. RESULTS: Model system experiments suggest that the method efficiently separates virus from cell-associated HIV, with a wide tolerance for incubation time and temperature. In 196 clinical samples, FVE reduced VL over-quantification from DBS, and improved DBS clinical concordance with plasma from 67% to 95%. CONCLUSIONS: A simple elution in PBS significantly reduced the over-quantification of HIV VL in DBS. Additional studies are needed to validate the method in fingerstick-collected specimens and to further understand the compartmentalization of HIV DNA and RNA in DBS specimens.

Sexual stigma, criminalization, investment, and access to HIV services among men who have sex with men worldwide.

Globally, HIV disproportionately affects men who have sex with men (MSM). This study explored associations between access to HIV services and (1) individual-level perceived sexual stigma; (2) country-level criminalization of homosexuality; and (3) country-level investment in HIV services for MSM. 3,340 MSM completed an online survey assessing access to HIV services. MSM from over 115 countries were categorized according to criminalization of homosexuality policy and investment in HIV services targeting MSM. Lower access to condoms, lubricants, and HIV testing were each associated with greater perceived sexual stigma, existence of homosexuality criminalization policies, and less investment in HIV services. Lower access to HIV treatment was associated with greater perceived sexual stigma and criminalization. Criminalization of homosexuality and low investment in HIV services were both associated with greater perceived sexual stigma. Efforts to prevent and treat HIV among MSM should be coupled with structural interventions to reduce stigma, overturn homosexuality criminalization policies, and increase investment in MSM-specific HIV services.

Cooperative spectrum sensing schemes with the interference constraint in cognitive radio networks.

In this paper, we propose cooperative spectrum sensing schemes, called decode-and-forward cooperative spectrum sensing (DF-CSS) scheme and amplify-and-forward cooperative spectrum sensing (AF-CSS) scheme, in cognitive radio networks. The main goals and features of the proposed cooperative spectrum sensing schemes are as follows: first, we solve the problem of high demand for bandwidth in a soft decision scheme using in our proposed schemes. Furthermore, the impact of transmission power of relaying users which is determined by the interference constraint on sensing performance of cooperative spectrum sensing schemes is also investigated. Second, we analyze the sensing performance of our proposed cooperative spectrum sensing schemes in terms of detection probability and interference probability, respectively. We take into account the interference caused by secondary user (SU) to primary user (PU) in the case that the transmission power of the relaying users exceeds a predefined interference constraint assigned by the primary user. The simulation results show that in cooperative spectrum sensing schemes the total sensing performance depends not only on the interference tolerance level, but also on the relay protocols used. We also prove that high transmission power of relaying users increases the interference between the secondary networks and the primary network.

Internalized homophobia and reduced HIV testing among men who have sex with men in China.

Although previous research has examined barriers and facilitators of HIV testing among men who have sex with men (MSM) in China, few studies have focused on social factors, including homophobia and internalized homophobia. This study utilized data from a global online survey to determine correlates of HIV testing as part of a subanalysis focused on Chinese MSM. Controlling for age, HIV knowledge, number of sexual partners, and other covariates, ever having tested for HIV was significantly correlated with lower internalized homophobia. This study suggests that stigma associated with sexual orientation may serve as a barrier to participation in HIV testing and other health-promoting behaviors.

Syndemic conditions associated with increased HIV risk in a global sample of men who have sex with men.

OBJECTIVE: We evaluated the relationship among syndemic conditions (defined as a cluster of interconnected psychosocial health conditions), sexual behaviours and self-reported HIV infection in a global sample of men who have sex with men (MSM). METHODS: We used generalised estimating equations logistic regression models with robust SEs to assess the relationships among cumulative number of syndemic conditions--including depression, substance use, violence, sexual stigma and homelessness--and unprotected anal intercourse (UAI) and HIV infection, while accounting for clustering within-country in a global cross-sectional survey of 3934 MSM across 151 countries. RESULTS: We observed parallel, significant dose-response associations between the number of syndemic conditions and UAI, as well as number of syndemic conditions and HIV infection. Compared with participants without syndemics, the adjusted OR (aOR) for UAI among those with 1, 2 and 3 or more syndemic conditions were 1.44 (Bonferroni-adjusted 95% CI 1.23 to 1.68), 1.89 (1.51 to 2.36) and 2.03 (1.43 to 2.89), respectively. Compared with participants without syndemics, the aOR for HIV infection among those with 1, 2 and 3 or more syndemic conditions were 1.67 (1.24 to 2.26), 2.02 (1.44 to 2.85) and 2.35 (1.31 to 4.21), respectively. CONCLUSIONS: This analysis provides evidence of intertwining syndemics that may operate synergistically to increase HIV risk among MSM globally. To curb HIV effectively and advance the health of MSM, multiple conditions must be addressed concurrently using multi-level approaches that target both individual and structural risk factors.

Chryseobacterium angstadtii sp. nov., isolated from a newt tank.

As part of an undergraduate microbiology course, a yellow-orange-pigmented, Gram-staining negative, rod-shaped, non-motile bacterial strain was isolated from a glass tank housing several red-spotted newts (Notophthalmus viridescens). The sequence of the 16S rRNA gene of this strain, designated KM(T), was 97.4-98.0 % similar to those of the type strains of Chryseobacterium luteum, C. shigense and C. vrystaatense, while the similarity levels for protein-coding genes were less than 94.7 % for rpoB, less than 92.1 % for groEL and less than 87.1 % for gyrB. These values are lower than for many other established distinct species. Polyphasic characterization and comparison to these relatives revealed that strain KM(T) was similar to other Chryseobacterium strains in that it contained MK-6 as its major respiratory quinone and phosphatidylethanolamine as the most abundant polar lipid, produced flexirubin-type pigments, oxidase and catalase and primarily contained the fatty acids iso-C15 : 0, iso-C17 : 1ω9c, iso-C17 : 0 3-OH and summed feature 3 (comprising C16 : 1ω6c and/or C16 : 1ω7c). Based on the results of this study, strain KM(T) represents a novel species, for which the name Chryseobacterium angstadtii sp. nov. is proposed. The type strain is KM(T) ( = ATCC BAA-2160(T) = NRRL B-59516(T) = KCTC 23297(T)).

Virologic suppression measured by a cytomegalovirus (CMV) DNA test calibrated to the World Health Organization international standard is predictive of CMV disease resolution in transplant recipients.

BACKGROUND: Cytomegalovirus (CMV) load measurement is used to assess the efficacy of treatment of CMV disease, but lacks standardization. Using the World Health Organization (WHO) international standard for reporting, we correlated viral load with CMV disease resolution. METHODS: CMV load was quantified in plasma using a test calibrated to the WHO standard. Three predictive rules were predefined to determine association between CMV DNAemia and outcome: (1) pretreatment CMV DNA of <18,200 (4.3 log(10)) IU/mL; (2) viral load declines of 1.0, 1.5, 2.0, and 2.5 log(10) IU/mL from baseline to days 7, 14, and 21 of treatment, respectively; and (3) viral suppression <137 (2.1 log(10)) IU/mL at days 7, 14, and 21. Analysis was performed using Cox proportional hazard models. RESULTS: Of 267 patients, 251 had CMV disease resolution by day 49 of treatment. Patients with pretreatment CMV DNA of <18,200 (4.3 log(10)) IU/mL had faster time to disease resolution (adjusted hazard ratio [AHR], 1.56; P = .001). Patients with CMV load suppression (<137 IU/mL [<2.1 log(10)]) at days 7, 14, and 21 had faster times to clinical disease resolution (AHRs, 1.61, 1.73, and 1.64, and P = .005, <.001, and <.001, respectively). Relative CMV load reductions from baseline were not significantly associated with faster resolution of CMV disease. CONCLUSIONS: Patients with pretreatment CMV DNA of <18,200 (4.3 log(10)) IU/mL are 1.5 times more likely to have CMV disease resolution. CMV suppression (<137 [2.1 log(10)] IU/mL), as measured by a test calibrated to the WHO Standard, is predictive of clinical response to antiviral treatment. CLINICAL TRIALS REGISTRATION: NCT00431353.