Effect of Anti-CD4 Antibody UB-421 on HIV-1 Rebound after Treatment Interruption.

BACKGROUND: Administration of a single broadly neutralizing human immunodeficiency virus (HIV)-specific antibody to HIV-infected persons leads to the development of antibody-resistant virus in the absence of antiretroviral therapy (ART). It is possible that monotherapy with UB-421, an antibody that blocks the virus-binding site on human CD4+ T cells, could induce sustained virologic suppression without induction of resistance in HIV-infected persons after analytic treatment interruption. METHODS: We conducted a nonrandomized, open-label, phase 2 clinical study evaluating the safety, pharmacokinetics, and antiviral activity of UB-421 monotherapy in HIV-infected persons undergoing analytic treatment interruption. All the participants had undetectable plasma viremia (<20 copies of HIV RNA per milliliter) at the screening visit. After discontinuation of ART, participants received eight intravenous infusions of UB-421, at a dose of either 10 mg per kilogram of body weight every week (Cohort 1) or 25 mg per kilogram every 2 weeks (Cohort 2). The primary outcome was the time to viral rebound (≥400 copies per milliliter). RESULTS: A total of 29 participants were enrolled, 14 in Cohort 1 and 15 in Cohort 2. Administration of UB-421 maintained virologic suppression (<20 copies per milliliter) in all the participants (94.5% of measurements at study visits 2 through 9) during analytic treatment interruption, with intermittent viral blips (range, 21 to 142 copies per milliliter) observed in 8 participants (28%). No study participants had plasma viral rebound to more than 400 copies per milliliter. CD4+ T-cell counts remained stable throughout the duration of the study. Rash, mostly of grade 1, was a common and transient adverse event; one participant discontinued the study drug owing to a rash. A decrease in the population of CD4+ regulatory T cells was observed during UB-421 monotherapy. CONCLUSIONS: UB-421 maintained virologic suppression (during the 8 to 16 weeks of study) in participants in the absence of ART. One participant discontinued therapy owing to a rash. (Funded by United Biomedical and others; ClinicalTrials.gov number, NCT02369146.).

Doravirine/Lamivudine/Tenofovir Disoproxil Fumarate is Non-inferior to Efavirenz/Emtricitabine/Tenofovir Disoproxil Fumarate in Treatment-naive Adults With Human Immunodeficiency Virus-1 Infection: Week 48 Results of the DRIVE-AHEAD Trial.

Background: Doravirine (DOR), a novel non-nucleoside reverse-transcriptase inhibitor (NNRTI), is active against wild-type Human Immunodeficiency Virus (HIV)-1 and the most common NNRTI-resistant variants, and has a favorable and unique in vitro resistance profile. Methods: DRIVE-AHEAD is a phase 3, double-blind, non-inferiority trial. Antiretroviral treatment-naive adults with ≥1000 HIV-1 RNA copies/mL were randomized (1:1) to once-daily, fixed-dose DOR at 100 mg, lamivudine at 300 mg, and tenofovir disoproxil fumarate (TDF) at 300 mg (DOR/3TC/TDF) or to efavirenz at 600 mg, emtricitabine at 200 mg, and TDF at 300 mg (EFV/FTC/TDF) for 96 weeks. The primary efficacy endpoint was the proportion of participants with <50 HIV-1 RNA copies/mL at week 48 (Food and Drug Administration snapshot approach; non-inferiority margin 10%). Results: Of the 734 participants randomized, 728 were treated (364 per group) and included in the analyses. At week 48, 84.3% (307/364) of DOR/3TC/TDF recipients and 80.8% (294/364) of EFV/FTC/TDF recipients achieved <50 HIV-1 RNA copies/mL (difference 3.5%, 95% CI, -2.0, 9.0). DOR/3TC/TDF recipients had significantly lower rates of dizziness (8.8% vs 37.1%), sleep disorders/disturbances (12.1% vs 25.2%), and altered sensorium (4.4% vs 8.2%) than EFV/FTC/TDF recipients. Mean changes in fasting low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol (non-HDL-C) were significantly different between DOR/3TC/TDF and EFV/FTC/TDF (-1.6 vs +8.7 mg/dL and -3.8 vs +13.3 mg/dL, respectively). Conclusions: In HIV-1 treatment-naive adults, DOR/3TC/TDF demonstrated non-inferior efficacy to EFV/FTC/TDF at week 48 and was well tolerated, with significantly fewer neuropsychiatric events and minimal changes in LDL-C and non-HDL-C compared with EFV/FTC/TDF. Clinical Trials Registration: NCT02403674.

Factors associated with pre-treatment HIV RNA: application for the use of abacavir and rilpivirine as the first-line regimen for HIV-infected patients in resource-limited settings.

BACKGROUND: Abacavir and rilpivirine are alternative antiretroviral drugs for treatment-naïve HIV-infected patients. However, both drugs are only recommended for the patients who have pre-treatment HIV RNA <100,000 copies/mL. In resource-limited settings, pre-treatment HIV RNA is not routinely performed and not widely available. The aims of this study are to determine factors associated with pre-treatment HIV RNA <100,000 copies/mL and to construct a model to predict this outcome. METHODS: HIV-infected adults enrolled in the TREAT Asia HIV Observational Database were eligible if they had an HIV RNA measurement documented at the time of ART initiation. The dataset was randomly split into a derivation data set (75% of patients) and a validation data set (25%). Factors associated with pre-treatment HIV RNA <100,000 copies/mL were evaluated by logistic regression adjusted for study site. A prediction model and prediction scores were created. RESULTS: A total of 2592 patients were enrolled for the analysis. Median [interquartile range (IQR)] age was 35.8 (29.9-42.5) years; CD4 count was 147 (50-248) cells/mm3; and pre-treatment HIV RNA was 100,000 (34,045-301,075) copies/mL. Factors associated with pre-treatment HIV RNA <100,000 copies/mL were age <30 years [OR 1.40 vs. 41-50 years; 95% confidence interval (CI) 1.10-1.80, p = 0.01], body mass index >30 kg/m2 (OR 2.4 vs. <18.5 kg/m2; 95% CI 1.1-5.1, p = 0.02), anemia (OR 1.70; 95% CI 1.40-2.10, p < 0.01), CD4 count >350 cells/mm3 (OR 3.9 vs. <100 cells/mm3; 95% CI 2.0-4.1, p < 0.01), total lymphocyte count >2000 cells/mm3 (OR 1.7 vs. <1000 cells/mm3; 95% CI 1.3-2.3, p < 0.01), and no prior AIDS-defining illness (OR 1.8; 95% CI 1.5-2.3, p < 0.01). Receiver-operator characteristic (ROC) analysis yielded area under the curve of 0.70 (95% CI 0.67-0.72) among derivation patients and 0.69 (95% CI 0.65-0.74) among validation patients. A cut off score >25 yielded the sensitivity of 46.7%, specificity of 79.1%, positive predictive value of 67.7%, and negative predictive value of 61.2% for prediction of pre-treatment HIV RNA <100,000 copies/mL among derivation patients. CONCLUSION: A model prediction for pre-treatment HIV RNA <100,000 copies/mL produced an area under the ROC curve of 0.70. A larger sample size for prediction model development as well as for model validation is warranted.

Tracing subsequent dissemination of a cluster of gonococcal infections caused by an ST1407-related clone harbouring mosaic penA alleles in Taiwan.

OBJECTIVES: Successful clones of Neisseria gonorrhoeae multiantigen sequence typing sequence type (ST) 1407 and ST1407-related genotypes have been reported to cause cefixime and ceftriaxone treatment failure in many countries. We characterized the 47 isolates of a strain cluster of ST4378, a genotype that differs in the porB sequence by only one nucleotide from ST1407, in Taiwan during April 2006 to June 2012. METHODS: We identified 47 ST4378 isolates among our 2357 total isolates from the Gonococci-National Isolate Collection for Epidemiology. The corresponding patients' medical records were collected. The 47 isolates were further typed by multilocus sequence typing. Genes involved in ß-lactam (ponA), quinolone (gyrA and parC) and multidrug (mtrR, porB1b and pilQ) resistance were sequenced. Antimicrobial susceptibility was determined by the disc diffusion test and Etest. RESULTS: Cefixime MICs for the 47 isolates ranged from 0.016 to 0.19 mg/L and ceftriaxone MICs ranged from 0.012 to 0.094 mg/L. Forty-six of the 47 isolates had a mosaic penA allele type XXXIV and one had a new allele type XL, which appeared to be a recombinant of mosaic penA type XXXIV and non-mosaic penA type II. All of the isolates harboured nearly identical polymorphism in the ponA, gyrA, parC, mtrR, porB1b and pilQ genes. Among the 33 patients with known medical records, 25 (76%) were men who have sex with men (MSM), 3 (9%) were bisexual and 5 (15%) were heterosexual. Fourteen (42%) of the 33 patients had HIV, 8 (24%) had syphilis and 7 (21%) had both infections. CONCLUSIONS: This is the first report of a cluster of ST1407-related strains in Taiwan. ST4378 is a genotype that may develop to cause third-generation cephalosporin treatment failures. Our results showed that ST4378 strains primarily transmitted in a high-risk MSM/bisexual network. The potential of these strains to become untreatable and spread to other low-risk sexual networks should be closely monitored.

Draft genome sequence of a dominant, multidrug-resistant Neisseria gonorrhoeae strain, TCDC-NG08107, from a sexual group at high risk of acquiring human immunodeficiency virus infection and syphilis.

Neisseria gonorrhoeae infection is the second major cause of sexually transmitted diseases worldwide. Development of resistance to multiple classes of antimicrobials in N. gonorrhoeae has compromised treatment and disease control. Herein, we report the availability of the draft genome sequence of a multidrug-resistant N. gonorrhoeae isolate, TCDC-NG08107, which spread in groups of men who have sex with men (MSM) in Taiwan.

Risk factors for HIV-1 seroconversion among Taiwanese men visiting gay saunas who have sex with men.

BACKGROUND: Men having sex with men (MSM) accounts for 33.6% of all reported cases of HIV-1 infection in Taiwan. The aim of this study was to investigate the epidemiology of HIV-1 infection among MSM in gay saunas in Taiwan. METHODS: Patrons of 5 gay saunas were recruited for a weekly volunteer counseling and testing program from 2001 to 2005. Questionnaires were collected for a risk factor analysis. HIV-1 subtypes were determined using DNA sequencing and phylogenetic analyses. RESULTS: HIV-1 prevalence rates among MSM in gay saunas in 2001 through 2005 were 3.4%, 5.1%, 8.9%, 8.5%, and 8.3%, respectively. In total, 81 of 1, 093 (7.4%) MSM had HIV-1 infection. Fifty-two HIV-1 strains were genotyped, and all of them were subtype B. HIV-seropositive men were significantly younger than the seronegatives. Only 37.1% used condoms every time during sexual intercourse. A multivariate logistic regression analysis showed that the risk factors for HIV-1 were being uncircumcised (odds ratio (OR) = 2.19; 95% confidence interval (CI), 1.08~4.45); having sexual intercourse with at least 2 partners during each sauna visit (≥ 2 vs. ≤ 1, OR = 1.71; 95% CI, 1.02~2.89); and the role played during anal intercourse (versatile vs. an exclusively insertive role, OR = 2.76; 95% CI, 1.42~5.36). CONCLUSIONS: Overall, 7.4% Taiwanese MSM participating in this study had HIV-1 subtype B infection. Uncircumcised, being versatile role during anal intercourse, and having sex with more than one person during each sauna visit were main risk factors for HIV-1 infection.

Detection of hepatitis C virus subtypes 6a, 6n, 6w and mixed infections using a modified multiplex real-time polymerase chain reaction protocol.

BACKGROUND/PURPOSE: In the past few years, many new subtypes in hepatitis C virus (HCV) genotype 6 have been identified. The aim of this study was to modify the multiplex real-time polymerase chain reaction (RT-PCR) protocol and use it to determine the HCV subtypes of a group of Taiwanese injection drug users (IDUs). METHODS: We used 76 serum specimens collected in northern Taiwan in 2008. Multiplex RT-PCR was used for HCV subtyping among those serum samples having anti-HCV antibodies. Twenty cases were randomly selected for comparison with subtyping results from Inno-LiPa II tests and phylogenetic tree analysis using NS5B sequences. RESULTS: Multiplex RT-PCR assays showed that 60.5% (46/76) of IDUs had single HCV infection. Three out of 76 (3.9%) had double HCV infection (1b/6a, 2a/2b and 2b/6a). Besides this, 27.6% (21/76) had no HCV signal. One IDU had subtype 6n and two had subtype 6w infection. Inno-LiPa II tests misclassified all 6n and 6w cases as 1b subtype. CONCLUSION: Our modified multiplex RT-PCR protocol can be used to support molecular epidemiological studies and laboratory diagnoses of different HCV subtypes including genotype 6.

Characteristics and dissemination of mosaic penicillin-binding protein 2-harboring multidrug-resistant Neisseria gonorrhoeae isolates with reduced cephalosporin susceptibility in northern Taiwan.

Among 254 Neisseria gonorrhoeae isolates from a sexually transmitted infection (STI) clinic in northern Taiwan, 69 isolates were found to contain the mosaic penA (MA) gene and were associated with elevated cefixime and ceftriaxone MICs. Most of these MA gene-harboring isolates were also resistant to penicillin (71.4%) and ciprofloxacin (100%) and were from men who have sex with men (MSM) or from bisexual men (81.2%). Three major sequence types (ST835, ST2180, and ST2253) constituted 55.7% of these isolates. The major sequence types harboring the mosaic penA gene may represent major sexual networks responsible for the emergence/introduction and the spread of the multidrug-resistant clones in Taiwan.

Shall I trust the report? Variable performance of Sanger sequencing revealed by deep sequencing on HIV drug resistance mutation detection.

BACKGROUND: The clinical utilisation of deep sequencing in HIV treatment has been hindered due to its unknown correlation with standard Sanger genotyping and the undetermined value of minority drug resistance mutation (DRM) detection. OBJECTIVES: To compare deep sequencing performance to standard Sanger genotyping with clinical samples, in an effort to delineate the correlation between the results from the two methods and to find the optimal deep sequencing threshold for clinical utilisation. METHODS: We conducted a retrospective study using stored plasma collected from August 2014 to March 2018 for HIV genotyping with the commercial Sanger genotyping kit. Samples with available Sanger genotyping reports were further deep sequenced. Drug resistance was interpreted according to the Stanford HIV drug resistance database algorithm. RESULTS: At 15-25% minority detection thresholds, 9-15% cases had underestimated DRMs by Sanger sequencing. The concordance between the Sanger and deep sequencing reports was 68-82% in protease-reverse transcriptase region and 88-97% in integrase region at 5-25% thresholds. The undetected drug resistant minority variants by Sanger sequencing contributed to the lower negative predictive value of Sanger genotyping in cases harbouring DRMs. CONCLUSIONS: Use of deep sequencing improved detection of antiretroviral resistance mutations especially in cases with virological failure or previous treatment interruption. Deep sequencing with 10-15% detection thresholds may be considered a suitable substitute for Sanger sequencing on antiretroviral DRM detection.

Seroprevalence of chronic hepatitis B virus infection among taiwanese human immunodeficiency virus type 1-positive persons in the era of nationwide hepatitis B vaccination.

OBJECTIVES: We aimed to assess the impact of nationwide hepatitis B virus (HBV) vaccination program on the seroprevalence of HBV infection among human immunodeficiency virus (HIV)-positive persons in a country where most HBV exposure occurs during the perinatal period or in early childhood. METHODS: Data on HBV surface antigen (HBsAg), anti-HBV surface (anti-HBs), anti-HBV core (anti-HBc), and anti-hepatitis C virus (anti-HCV) antibody were retrospectively collected from 3,164 HIV-positive and 2,594 HIV-negative persons between 2004 and 2007. Comparisons of serological markers of HBV and HCV were made between HIV-positive and -negative adults born before and after the implementation of the HBV vaccination program in Taiwan in July 1984. RESULTS: Compared with HIV-negative persons, the adjusted odds ratio for HBsAg seropositivity was 1.100 (95% confidence interval, 0.921-1.315) among HIV-positive persons. Although the seroprevalence of anti-HCV antibody remained similar between HIV-positive persons born before and those born after 1984, the seroprevalence of HBsAg declined from 20.3 to 3.3% in HIV-positive persons (P<0.001) and from 15.5 to 8.5% in HIV-negative persons (P<0.001). Despite the high seroprevalence of anti-HCV antibody (97.1%) in HIV-positive injecting drug users (IDUs), there was no statistically significant difference in the seroprevalence of HBsAg (5.6% vs. 8.5%, P=0.75) or anti-HBc antibody (40.7% vs. 27.9%, P=0.14) between HIV-positive IDUs and HIV-negative persons who were born after 1984. CONCLUSIONS: Our study showed a significant decline of seroprevalence of HBV infection among both HIV-negative and -positive persons who were born in the era of the nationwide HBV vaccination in Taiwan.

Cotrimoxazole prophylaxis decreases tuberculosis risk among Asian patients with HIV.

INTRODUCTION: Cotrimoxazole (CTX) is recommended as prophylaxis against Pneumocystis jiroveci pneumonia, malaria and other serious bacterial infections in HIV-infected patients. Despite its in vitro activity against Mycobacterium tuberculosis, the effects of CTX preventive therapy on tuberculosis (TB) remain unclear. METHODS: Adults living with HIV enrolled in a regional observational cohort in Asia who had initiated combination antiretroviral therapy (cART) were included in the analysis. Factors associated with new TB diagnoses after cohort entry and survival after cART initiation were analysed using Cox regression, stratified by site. RESULTS: A total of 7355 patients from 12 countries enrolled into the cohort between 2003 and 2016 were included in the study. There were 368 reported cases of TB after cohort entry with an incidence rate of 0.99 per 100 person-years (/100 pys). Multivariate analyses adjusted for viral load (VL), CD4 count, body mass index (BMI) and cART duration showed that CTX reduced the hazard for new TB infection by 28% (HR 0.72, 95% CI l 0.56, 0.93). Mortality after cART initiation was 0.85/100 pys, with a median follow-up time of 4.63 years. Predictors of survival included age, female sex, hepatitis C co-infection, TB diagnosis, HIV VL, CD4 count and BMI. CONCLUSIONS: CTX was associated with a reduction in the hazard for new TB infection but did not impact survival in our Asian cohort. The potential preventive effect of CTX against TB during periods of severe immunosuppression should be further explored.

Genotyping of Chlamydia trachomatis by microsphere suspension array.

The identification of Chlamydia trachomatis genotypes is important for both the study of molecular epidemiology and infection control. We have developed a microsphere suspension array assay that can identify C. trachomatis genotypes rapidly and accurately and also discriminate among multiple genotypes in one clinical specimen.

Molecular epidemiological identification of Neisseria gonorrhoeae clonal clusters with distinct susceptibility profiles associated with specific groups at high risk of contracting human immunodeficiency virus and syphilis.

From April 2006 to August 2007, a total of 146 Neisseria gonorrhoeae isolates collected from 139 male patients in Taipei, Taiwan, were analyzed by N. gonorrhoeae multiantigen sequence typing (NG-MAST) and antibiotic susceptibility testing. The resistance rates of all isolates to ciprofloxacin, cefpodoxime, and cefixime were 76.7 (112/146), 21.2 (31/146), and 16.4% (24/146), respectively. NG-MAST identified 71 sequence types (STs), of which 21 STs contained 2 to 21 isolates. The isolates that belonged to the three major ST clusters typically were from patients who had specific epidemiological characteristics (such as sexual orientation and human immunodeficiency virus status). The major ST clones exhibited distinct resistance profiles and are associated with specific groups at high risk of human immunodeficiency virus and syphilis infections.

Optimal timing for elective total hip replacement in HIV-positive patients.

INTRODUCTION: Evidence about the optimal timing for total hip replacement (THR) in HIV-positive patients is scant. HYPOTHESIS: Preoperative criteria: cluster of differentiation 4 (CD4) counts>200cells/mm3 and an undetectable HIV virus load before THR, improve infection rates, aseptic loosenings, and functional outcomes. MATERIALS AND METHODS: We recruited 16 HIV-positive patients who had undergone 25 THRs between 2003 and 2015. None had hemophilia, and none were intravenous drug users (IVDUs). RESULTS: Their mean age was 41.2 years (range: 24-60); minimum follow-up was 12 months (mean: 64.6); mean duration of prophylactic antibiotics was 2.9 days (range: 1-5); and mean hospital length of stay was 6.0 days (range: 4-11). No patients were treated with subsequent oral antibiotics. The mean preoperative CD4 count was 464.1±237.0 (range: 235-904)cells/mm3. There were no early superficial surgical site infections, late periprosthetic joint infections, or aseptic loosenings. Post-surgery Harris Hip score was significantly (p<0.001) better. DISCUSSION: A preoperative CD4 count>200cell/mm3 and an undetectable HIV virus load might indicate optimal timing for elective THRs in HIV-positive patients without hemophilia and not IVDUs. LEVEL OF EVIDENCE: IV, retrospective or historical series.

Rifabutin-induced hypopyon uveitis in patients with acquired immunodeficiency syndrome infected with Mycobacterium avium complex.

Rifabutin is a semi-synthetic antimycobacterial agent mainly used in the prophylaxis and treatment of Mycobacterium avium complex (MAC) in acquired immunodeficiency syndrome patients. Uveitis as a side effect of rifabutin has been recognized and established since 1994, but there was no case previously described in Taiwan so far. We report 2 cases of rifabutin-induced hypopyon uveitis in patients with human immunodeficiency virus and MAC infection. Both patients received the regimen of clarithromycin and rifabutin to treat MAC infection. Uveitis resolved after discontinuing of rifabutin and treatment with topical corticosteroid and mydriatics. Early recognition of this entity can prevent invasive ocular procedures and treatments. Doctors who prescribe rifabutin should be aware of this ocular complication of uveitis and drug-drug interactions. Ophthalmologists should put this on the list of differential diagnoses for uveitis.

Cardiovascular Disease and Cardiovascular Disease Risk in HIV-Positive Populations in the Asian Region.

INTRODUCTION: Cardiovascular diseases (CVD) are becoming more prevalent in HIV-infected populations as they age largely due to improved treatment outcomes. Assessment of CVD risk and CVD risk factors in HIV-positive populations has focused on high income settings, while there are limited studies evaluating CVD in HIV-positive populations in the Asian region. MATERIALS AND METHODS: We provided an overview of the prevalence and incidence of CVD and its risk factors in adult HIV-positive populations, and of the strategies currently in place for CVD management in the Asian region. RESULTS: Studies from the Asian region showed that CVD and CVD risk factors, such as dyslipidaemia, elevated blood glucose, obesity and smoking, are highly prevalent in HIV-positive populations. A number of studies suggested that HIV infection and antiretroviral therapy may contribute to increased CVD risk. National HIV treatment guidelines provide some directions regarding CVD risk prevention and management in the HIV-infected population, however, they are limited in number and scope. CONCLUSION: Development and consolidation of guidelines for integrated CVD and HIV care are essential to control the burden of CVD in HIV-positive populations. To inform guidelines, policies and practice in the Asian region, research should focus on exploring appropriate CVD risk screening strategies and estimating current and future CVD mortality and morbidity rates.

The treatment outcomes of antiretroviral substitutions in routine clinical settings in Asia; data from the TREAT Asia HIV Observational Database (TAHOD).

INTRODUCTION: Although substitutions of antiretroviral regimen are generally safe, most data on substitutions are based on results from clinical trials. The objective of this study was to evaluate the treatment outcomes of substituting antiretroviral regimen in virologically suppressed HIV-infected patients in non-clinical trial settings in Asian countries. METHODS: The study population consisted of HIV-infected patients enrolled in the TREAT Asia HIV Observational Database (TAHOD). Individuals were included in this analysis if they started combination antiretroviral treatment (cART) after 2002, were being treated at a centre that documented a median rate of viral load monitoring ≥0.8 tests/patient/year among TAHOD enrolees, and experienced a minor or major treatment substitution while on virally suppressive cART. The primary endpoint to evaluate outcomes was clinical or virological failure (VF), followed by an ART class change. Clinical failure was defined as death or an AIDS diagnosis. VF was defined as confirmed viral load measurements ≥400 copies/mL followed by an ART class change within six months. Minor regimen substitutions were defined as within-class changes and major regimen substitutions were defined as changes to a drug class. The patterns of substitutions and rate of clinical or VF after substitutions were analyzed. RESULTS: Of 3994 adults who started ART after 2002, 3119 (78.1%) had at least one period of virological suppression. Among these, 1170 (37.5%) underwent a minor regimen substitution, and 296 (9.5%) underwent a major regimen substitution during suppression. The rates of clinical or VF were 1.48/100 person years (95% CI 1.14 to 1.91) in the minor substitution group, 2.85/100 person years (95% CI 1.88 to 4.33) in the major substitution group and 2.53/100 person years (95% CI 2.20 to 2.92) among patients that did not undergo a treatment substitution. CONCLUSIONS: The rate of clinical or VF was low in both major and minor substitution groups, showing that regimen substitution is generally effective in non-clinical trial settings in Asian countries.

Molecular epidemiology of HIV type 1 subtypes in Taiwan: outbreak of HIV type 1 CRF07_BC infection in intravenous drug users.

In Taiwan, sexual transmission is responsible for most HIV-1 infections with two dominant subtypes, subtype B and CRF01_AE, distributing among homosexual and heterosexual groups, respectively. Recently, intravenous drug use has become an emerging route of HIV-1 transmission and contributed to a significant increase of HIV-1 infection. To characterize the HIV isolates responsible for the outbreak among intravenous drug users (IDUs), phylogenetic analysis was performed to analyze the protease/RT sequences amplified from HIV-1-infected IDUs at National Taiwan University Hospital and Taipei City STD Control Center. CRF07_BC, which is circulating in northern China, was demonstrated to account for the majority of HIV-1 infection in IDUs in the past 2 years. Although these Taiwanese CRF07_BC sequences shared the same breakpoint positions as those described in the CRF07_BC reference sequences, they formed a unique cluster in the phylogenetic tree, suggesting they originated from a founder virus. This finding was further supported by the relative low genetic diversity and unique sequence features. Our results demonstrated the emergence of CRF07_BC and its association with the HIV-1 outbreak among IDUs between 2004 and 2005 in Taiwan. This finding not only helps us to have a better understanding of the HIV evolution in Asia, but also has important implications for vaccine design in the future.