Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where William Towner is active.

Publication


Featured researches published by William Towner.


The Lancet | 2007

Efficacy and safety of TMC125 (etravirine) in treatment-experienced HIV-1-infected patients in DUET-2: 24-week results from a randomised, double-blind, placebo-controlled trial

Adriano Lazzarin; Thomas B. Campbell; Bonaventura Clotet; Margaret Johnson; Christine Katlama; Arend Moll; William Towner; Benoit Trottier; M Peeters; Johan Vingerhoets; Goedele De Smedt; Benny Baeten; Greet Beets; Rekha Sinha; Brian Woodfall

BACKGROUND TMC125 (etravirine) is a non-nucleoside reverse-transcriptase inhibitor (NNRTI) with activity against NNRTI-resistant HIV-1 in phase IIb trials. The aim of DUET-2 is to examine the efficacy, tolerability, and safety of TMC125 in treatment-experienced patients. METHODS In this continuing randomised, double-blind, placebo-controlled, phase III trial, HIV-1-infected patients on failing antiretroviral therapy with evidence of resistance to currently available NNRTIs and at least three primary protease inhibitor mutations were eligible for enrolment if on stable (8 weeks unchanged) antiretroviral therapy with plasma HIV-1 RNA greater than 5000 copies per mL. Patients were randomly assigned to receive either TMC125 (200 mg) or placebo, each given twice daily with darunavir-ritonavir, investigator-selected nucleoside/nucleotide reverse transcriptase inhibitors, and optional enfuvirtide. The primary endpoint was the proportion of patients with confirmed viral load below 50 copies per mL at week 24 (FDA time-to-loss of virological response algorithm). Analyses were by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00255099. FINDINGS 591 patients were randomised and treated (295 patients in the TMC125 group and 296 in the placebo group). By week 24, 51 (17%) patients in the TMC125 group and 73 (25%) in the placebo group had discontinued, mainly because of virological failure. 183 (62%) patients in the TMC125 group and 129 (44%) in the placebo group achieved confirmed viral load below 50 copies per mL at week 24 (difference 18%, 95% CI 11-26; p=0.0003). The type and frequency of adverse events were much the same in the two groups. INTERPRETATION In treatment-experienced patients, treatment with TMC125 led to better virological suppression at week 24 than did placebo. The safety and tolerability profile of TMC125 was generally comparable with placebo.


The Lancet | 2014

All-oral daclatasvir plus asunaprevir for hepatitis C virus genotype 1b: a multinational, phase 3, multicohort study

Michael P. Manns; Stanislas Pol; Ira M. Jacobson; Patrick Marcellin; Stuart C. Gordon; Cheng Yuan Peng; Ting-Tsung Chang; Gregory T. Everson; Jeong Heo; Guido Gerken; Boris Yoffe; William Towner; Marc Bourlière; S. Metivier; Chi-Jen Chu; William Sievert; Jean-Pierre Bronowicki; Dominique Thabut; Youn-Jae Lee; Jia-Horng Kao; Fiona McPhee; Justin Kopit; Patricia Mendez; Misti Linaberry; Eric Hughes; Stephanie Noviello

BACKGROUND An unmet need exists for interferon-free and ribavirin-free treatments for chronic hepatitis C virus (HCV) infection. In this study, we assessed all-oral therapy with daclatasvir (NS5A replication complex inhibitor) plus asunaprevir (NS3 protease inhibitor) in patients with genotype 1b infection, including those with high unmet needs or cirrhosis, or both. METHODS We did this phase 3, multicohort study (HALLMARK-DUAL) at 116 sites in 18 countries between May 11, 2012, and Oct 9, 2013. Patients were adults with chronic HCV genotype 1b infection who were treatment-naive; previous non-responders to peginterferon alfa plus ribavirin; or medically ineligible for, previously intolerant of, or ineligible for and intolerant of peginterferon alfa plus ribavirin. Treatment-naive patients were randomly assigned (2:1 ratio) by an interactive voice-response system with a computer-generated random allocation sequence (stratified by cirrhosis status) to receive daclatasvir 60 mg once daily plus asunaprevir 100 mg twice daily or placebo for 12 weeks. Patients and investigator sites were masked to treatment assignment and HCV RNA results to the end of week 12. The treatment-naive group assigned to daclatasvir plus asunaprevir continued open-label treatment to the end of week 24; participants assigned to placebo entered another daclatasvir plus asunaprevir study. Non-responders and ineligible, intolerant, or ineligible and intolerant patients received open-label daclatasvir plus asunaprevir for 24 weeks. The primary endpoint was sustained virological response at post-treatment week 12. Efficacy analyses were restricted to patients given daclatasvir plus asunaprevir. This trial is registered with ClinicalTrials.gov, number NCT01581203. FINDINGS This study included 307 treatment-naive patients (205 received daclatasvir plus asunaprevir and 102 received placebo; all randomly assigned patients received the intended treatment), 205 non-responders, and 235 ineligible, intolerant, or ineligible and intolerant patients. Daclatasvir plus asunaprevir provided sustained virological response in 182 (90%, 95% CI 85-94) patients in the treatment-naive cohort, 168 (82%, 77-87) in the non-responder cohort, and 192 (82%, 77-87) in the ineligible, intolerant, or ineligible and intolerant cohort. Serious adverse events occurred in 12 (6%) patients in the treatment-naive group; 11 (5%) non-responders, and 16 (7%) ineligible, intolerant, or ineligible and intolerant patients; adverse events leading to discontinuation (most commonly reversible increases in alanine or aspartate aminotransferase) occurred in six (3%), two (1%), and two (1%) patients, respectively, with no deaths recorded. Grade 3 or 4 laboratory abnormalities were uncommon, with low incidences of aminotransferase increases during the first 12 weeks with daclatasvir plus asunaprevir and placebo in treatment-naive patients (≤2% each). INTERPRETATION Daclatasvir plus asunaprevir provided high sustained virological response rates in treatment-naive, non-responder, and ineligible, intolerant, or ineligible and intolerant patients, and was well tolerated in patients with HCV genotype 1b infection. These results support the use of daclatasvir plus asunaprevir as an all-oral, interferon-free and ribavirin-free treatment option for patients with HCV genotype 1b infection, including those with cirrhosis. FUNDING Bristol-Myers Squibb.


The New England Journal of Medicine | 2015

Ledipasvir and Sofosbuvir for HCV in Patients Coinfected with HIV-1

Susanna Naggie; Curtis Cooper; Michael S. Saag; Kimberly A. Workowski; Peter Ruane; William Towner; Kristen M. Marks; Anne F. Luetkemeyer; Rachel Baden; Paul E. Sax; Edward Gane; Jorge Santana-Bagur; Luisa M. Stamm; Jenny C. Yang; Polina German; Hadas Dvory-Sobol; Liyun Ni; Phillip S. Pang; John G. McHutchison; Catherine A. Stedman; Javier Morales-Ramirez; Norbert Bräu; Dushyantha Jayaweera; Amy E. Colson; Pablo Tebas; David Wong; Douglas T. Dieterich; Mark S. Sulkowski

BACKGROUND Effective treatment for hepatitis C virus (HCV) in patients coinfected with human immunodeficiency virus type 1 (HIV-1) remains an unmet medical need. METHODS We conducted a multicenter, single-group, open-label study involving patients coinfected with HIV-1 and genotype 1 or 4 HCV receiving an antiretroviral regimen of tenofovir and emtricitabine with efavirenz, rilpivirine, or raltegravir. All patients received ledipasvir, an NS5A inhibitor, and sofosbuvir, a nucleotide polymerase inhibitor, as a single fixed-dose combination for 12 weeks. The primary end point was a sustained virologic response at 12 weeks after the end of therapy. RESULTS Of the 335 patients enrolled, 34% were black, 55% had been previously treated for HCV, and 20% had cirrhosis. Overall, 322 patients (96%) had a sustained virologic response at 12 weeks after the end of therapy (95% confidence interval [CI], 93 to 98), including rates of 96% (95% CI, 93 to 98) in patients with HCV genotype 1a, 96% (95% CI, 89 to 99) in those with HCV genotype 1b, and 100% (95% CI, 63 to 100) in those with HCV genotype 4. Rates of sustained virologic response were similar regardless of previous treatment or the presence of cirrhosis. Of the 13 patients who did not have a sustained virologic response, 10 had a relapse after the end of treatment. No patient had confirmed HIV-1 virologic rebound. The most common adverse events were headache (25%), fatigue (21%), and diarrhea (11%). No patient discontinued treatment because of adverse events. CONCLUSIONS Ledipasvir and sofosbuvir for 12 weeks provided high rates of sustained virologic response in patients coinfected with HIV-1 and HCV genotype 1 or 4. (Funded by Gilead Sciences; ION-4 ClinicalTrials.gov number, NCT02073656.).


AIDS | 2009

HIV INFECTION AND THE RISK OF CANCERS WITH AND WITHOUT A KNOWN INFECTIOUS CAUSE

Michael J. Silverberg; Chun Chao; Wendy A. Leyden; Lanfang Xu; Beth Tang; Michael A. Horberg; Daniel Klein; Charles P. Quesenberry; William Towner; Donald I. Abrams

Objective:To evaluate the risk of cancers with and without a known infectious cause in HIV-infected persons. Design:Retrospective cohort study. Methods:Adult HIV-infected and matched HIV-uninfected members of Kaiser Permanente followed between 1996 and 2007 for incident AIDS-defining cancers (ADCs), infection-related non-AIDS-defining cancers (NADCs; anal squamous cell, vagina/vulva, Hodgkins lymphoma, penis, liver, human papillomavirus-related oral cavity/pharynx, stomach) and infection-unrelated NADC (all other NADCs). Results:We identified 20 277 HIV-infected and 202 313 HIV-uninfected persons. HIV-infected persons experienced 552 ADC, 221 infection-related NADC, and 388 infection-unrelated NADC. HIV-uninfected persons experienced 179 ADC, 284 infection-related NADC, and 3418 infection-unrelated NADC. The rate ratio comparing HIV-infected and HIV-uninfected persons for ADC was 37.7 [95% confidence interval (CI): 31.7–44.8], with decreases in the rate ratio over time (P < 0.001). The rate ratio for infection-related NADC was 9.2 (95% CI: 7.7–11.1), also with decreases in the rate ratio over time (P < 0.001). These results were largely influenced by anal squamous cell cancer and Hodgkins lymphoma. The rate ratio for infection-unrelated NADC was 1.3 (95% CI: 1.2–1.4), with no change in the rate ratio over time (P = 0.44). Among infection-unrelated NADCs, other anal, skin, other head and neck, and lung cancer rates were higher and prostate cancer rates lower in HIV-infected persons. Among all infection-unrelated NADCs, the rate ratio decreased over time only for lung cancer (P = 0.007). Conclusion:In comparison with those without HIV infection, HIV-infected persons are at particular risk for cancers with a known infectious cause, although the higher risk has decreased in the antiretroviral therapy era. Cancers without a known infectious cause are modestly increased in HIV-infected persons compared with HIV-uninfected persons.


Journal of Acquired Immune Deficiency Syndromes | 2008

Effects of depression and selective serotonin reuptake inhibitor use on adherence to highly active antiretroviral therapy and on clinical outcomes in HIV-infected patients.

Michael A. Horberg; Michael J. Silverberg; Leo B. Hurley; William Towner; Daniel Klein; Susan Bersoff-Matcha; Winkler Weinberg; Diana Antoniskis; Miguel Mogyoros; Wayne Thomas Dodge; Robert Dobrinich; Charles Price Quesenberry; Drew Kovach

Objectives:To determine the impact of depression on highly active antiretroviral therapy (HAART) adherence and clinical measures and investigate if selective serotonin reuptake inhibitors (SSRIs) improve these measures. Design:Retrospective cohort study. Methods:In 2 large health maintenance organizations, we measured the effects of depression (with and without SSRI use) on adherence and changes in viral and immunologic control among HIV-infected patients starting a new HAART regimen. HAART adherence, HIV RNA levels, and changes in CD4 T-cell counts through 12 months were measured. Results:A total of 3359 patients were evaluated; 42% had a depression diagnosis, and 15% used SSRIs during HAART. Depression without SSRI use was associated with significantly decreased odds of achieving ≥90% adherence to HAART (odds ratio [OR] = 0.81, 95% confidence interval [CI]: 0.70 to 0.98; P = 0.03). Depression was associated with significantly lower odds of an HIV RNA level <500 copies/mL (OR = 0.77, 95% CI: 0.62 to 0.95; P = 0.02). Depressed patients compliant with SSRI medication (>80% adherence to SSRI) had HAART adherence and viral control statistically similar to nondepressed HIV-infected patients taking HAART. Comparing depressed with nondepressed HIV-infected patients, CD4 T-cell responses were statistically similar; among depressed patients, those compliant with SSRI had statistically greater increases in CD4 cell responses. Conclusions:Depression significantly worsens HAART adherence and HIV viral control. Compliant SSRI use is associated with improved HIV adherence and laboratory parameters.


Cancer Epidemiology, Biomarkers & Prevention | 2011

HIV Infection, Immunodeficiency, Viral Replication, and the Risk of Cancer

Michael J. Silverberg; Chun Chao; Wendy A. Leyden; Lanfang Xu; Michael A. Horberg; Daniel Klein; William Towner; Robert Dubrow; Charles P. Quesenberry; Romain Neugebauer; Donald I. Abrams

Background: Few studies have compared cancer risk between HIV-infected individuals and a demographically similar HIV-uninfected internal comparison group, adjusting for cancer risk factors. Methods: We followed 20,775 HIV-infected and 215,158 HIV-uninfected individuals enrolled in Kaiser Permanente (KP) California for incident cancer from 1996 to 2008. Rate ratios (RR) were obtained from Poisson models comparing HIV-infected (overall and stratified by recent CD4 count and HIV RNA) with HIV-uninfected individuals, adjusted for age, sex, race/ethnicity, calendar period, KP region, smoking, alcohol/drug abuse, and overweight/obesity. Results: We observed elevated RRs for Kaposi sarcoma (KS; RR = 199; P < 0.001), non-Hodgkin lymphoma (NHL; RR = 15; P < 0.001), anal cancer (RR = 55; P < 0.001), Hodgkin lymphoma (HL; RR = 19; P < 0.001), melanoma (RR = 1.8; P = 0.001), and liver cancer (RR = 1.8; P = 0.013), a reduced RR for prostate cancer (RR = 0.8; P = 0.012), and no increased risk for oral cavity/pharynx (RR = 1.4; P = 0.14), lung (RR = 1.2; P = 0.15), or colorectal (RR = 0.9; P = 0.34) cancers. Lung and oral cavity/pharynx cancers were elevated for HIV-infected subjects in models adjusted only for demographics. KS, NHL, anal cancer, HL, and colorectal cancer had significant (P < 0.05) trends for increasing RRs with decreasing recent CD4. The RRs for lung and oral cavity/pharynx cancer were significantly elevated with CD4 < 200 cells/μL and for melanoma and liver cancer with CD4 < 500 cells/μL. Only KS and NHL were associated with HIV RNA. Conclusion: Immunodeficiency was positively associated with all cancers examined except prostate cancer among HIV-infected compared with HIV-uninfected individuals, after adjustment for several cancer risk factors. Impact: Earlier antiretroviral therapy initiation to maintain high CD4 levels might reduce the burden of cancer in this population. Cancer Epidemiol Biomarkers Prev; 20(12); 2551–9. ©2011 AACR.


Journal of Acquired Immune Deficiency Syndromes | 2010

Impact of tenofovir on renal function in HIV-infected, antiretroviral-naive patients.

Michael A. Horberg; Beth Tang; William Towner; Michael J. Silverberg; Susan Bersoff-Matcha; Leo B. Hurley; Joseph Chang; Jackie Blank; Charles P. Quesenberry; Daniel Klein

Objective:To better characterize the long-term effects of tenofovir on renal function in a large managed care organization. Methods:We performed a retrospective cohort analysis in Kaiser Permanente for years 2002 to 2005 comparing renal function among antiretroviral naïve patients initiating a tenofovir-containing regimen (964 patients) or tenofovir-sparing regimens (683 patients). We evaluated glomerular filtration rate (GFR, [Modification of Diet in Renal Disease equation]), serum creatinine, and the development of renal proximal tubular dysfunction. We report multivariable hazard ratios (HR, Cox modeling) and linear outcomes (repeated measures) with predictors retained if P < 0.10 (backward selection). Potential predictor variables included in multivariate models were age, sex, Black race, baseline laboratories (including CD4 count), history of diabetes mellitus, hypertension, malignancy, hepatitis, and concurrent medications. Results:Overall, tenofovir-exposed patients had a larger relative decline in GFR through 104 weeks (−7.6 mL/min/1.73 m2 relative to tenofovir-sparing, P < 0.001); the degree of the difference varied by baseline GFR, with the greatest effect seen in those patients with GFR greater than 80 mL/min/1.73 m2. Tenofovir-exposed patients had greater development of proximal tubular dysfunction over time (at 52 wk: HRadjusted = 1.95 [P = 0.01] and at 104 wk: HRadjusted = 5.23 [P = 0.0004]) and had greater risk of medication discontinuation (HRadjusted = 1.21, P = 0.02), especially as renal function worsened. Viral control and CD4 count changes were similar between the two groups. Conclusions:Tenofovir is associated with greater effect on decline in renal function and a higher risk of proximal tubular dysfunction in antiretroviral naïve patients initiating antiretroviral therapy.


Antimicrobial Agents and Chemotherapy | 2010

HIV-1 Protease Mutations and Protease Inhibitor Cross-Resistance

Soo-Yon Rhee; Jonathan Taylor; W. Jeffrey Fessel; David A. Kaufman; William Towner; Paolo Troia; Peter Ruane; James Hellinger; Vivian Shirvani; Andrew R. Zolopa; Robert W. Shafer

ABSTRACT The effects of many protease inhibitor (PI)-selected mutations on the susceptibility to individual PIs are unknown. We analyzed in vitro susceptibility test results on 2,725 HIV-1 protease isolates. More than 2,400 isolates had been tested for susceptibility to fosamprenavir, indinavir, nelfinavir, and saquinavir; 2,130 isolates had been tested for susceptibility to lopinavir; 1,644 isolates had been tested for susceptibility to atazanavir; 1,265 isolates had been tested for susceptibility to tipranavir; and 642 isolates had been tested for susceptibility to darunavir. We applied least-angle regression (LARS) to the 200 most common mutations in the data set and identified a set of 46 mutations associated with decreased PI susceptibility of which 40 were not polymorphic in the eight most common HIV-1 group M subtypes. We then used least-squares regression to ascertain the relative contribution of each of these 46 mutations. The median number of mutations associated with decreased susceptibility to each PI was 28 (range, 19 to 32), and the median number of mutations associated with increased susceptibility to each PI was 2.5 (range, 1 to 8). Of the mutations with the greatest effect on PI susceptibility, I84AV was associated with decreased susceptibility to eight PIs; V32I, G48V, I54ALMSTV, V82F, and L90M were associated with decreased susceptibility to six to seven PIs; I47A, G48M, I50V, L76V, V82ST, and N88S were associated with decreased susceptibility to four to five PIs; and D30N, I50L, and V82AL were associated with decreased susceptibility to fewer than four PIs. This study underscores the greater impact of nonpolymorphic mutations compared with polymorphic mutations on decreased PI susceptibility and provides a comprehensive quantitative assessment of the effects of individual mutations on susceptibility to the eight clinically available PIs.


Antiviral Therapy | 2010

Efficacy and safety of etravirine at week 96 in treatment-experienced HIV type-1-infected patients in the DUET-1 and DUET-2 trials.

Christine Katlama; Bonaventura Clotet; Anthony Mills; Benoit Trottier; Jean-Michel Molina; Beatriz Grinsztejn; William Towner; Richard Haubrich; Steven Nijs; Johan Vingerhoets; Brian Woodfall; James Witek

BACKGROUND Durable efficacy and long-term safety of antiretroviral therapy are important goals in the management of treatment-experienced patients. The 96-week efficacy and safety of the non-nucleoside reverse transcriptase inhibitor (NNRTI) etravirine were evaluated in the Phase III DUET trials. METHODS HIV type-1-infected treatment-experienced adults with viral loads >5,000 copies/ml and NNRTI and protease inhibitor resistance were randomized to receive etravirine 200 mg or placebo, each twice daily and in combination with a background regimen of darunavir/ritonavir twice daily, nucleoside/nucleotide reverse transcriptase inhibitors and optional enfuvirtide. The primary end point was the proportion of patients with viral load <50 copies/ml (intent-to-treat analysis, time-to-loss of virological response algorithm) at week 24. Results from both trials were combined in the pre-specified pooled 96-week analysis. RESULTS In total, 599 patients received etravirine and 604 received placebo. At week 96, 57% of patients in the etravirine group versus 36% in the placebo group had a viral load <50 copies/ml (P<0.0001); 91% and 88% of patients, respectively, had maintained this response from week 48. Mean increases in CD4(+) T-cell count from baseline at week 96 were 128 cells/mm(3) with etravirine versus 86 cells/mm(3) with placebo (P<0.0001). With the exception of rash, which was reported more frequently with etravirine than placebo (21% versus 12%, respectively; P<0.0001), the safety and tolerability profile of etravirine was similar to placebo over the treatment period. CONCLUSIONS Etravirine, in combination with an antiretroviral background regimen, provided durable virological and immunological responses with no new safety concerns in treatment-experienced patients over 96 weeks in the DUET trials.


Journal of Acquired Immune Deficiency Syndromes | 2014

Immunodeficiency and risk of myocardial infarction among HIV-positive individuals with access to care.

Michael J. Silverberg; Wendy A. Leyden; Lanfang Xu; Michael A. Horberg; Chun R. Chao; William Towner; Leo B. Hurley; Charles P. Quesenberry; Daniel Klein

Background:We sought to clarify the association of HIV infection and immunodeficiency on myocardial infarction (MI) risk. Methods:We conducted a cohort study from 1996 to 2009 of HIV-positive (HIV+) and demographically matched HIV-negative (HIV−) Kaiser Permanente California health plan members. Rate ratios (RRs) were obtained from Poisson regression models comparing MI incidence rates between HIV+ (overall and stratified by recent and nadir CD4 count, and recent HIV RNA levels) and HIV− subjects, adjusting for age, sex, calendar era, race/ethnicity, census-based socioeconomic status, smoking, alcohol/drug abuse, overweight/obesity, diabetes, hypertension, and lipid-lowering therapy. Among HIV+ subjects, we also evaluated the independent association of CD4, HIV RNA, and antiretroviral therapy (ART) use. Results:The study population included 22,081 HIV+ and 230,069 HIV− subjects. The crude MI incidence rate per 100,000 person-years was 283 and 165 for HIV+ and HIV− subjects, respectively, with an adjusted RR of 1.4 [95% confidence interval (CI): 1.3 to 1.6]. Compared with HIV− subjects (reference), MI rates were similar for HIV+ subjects with recent CD4 ≥500 cells per microliter (RR = 1.18; 95% CI: 0.96 to 1.45) and those with nadir CD4 ≥500 cells per microliter (RR = 0.85; 95% CI: 0.55 to 1.33). Among HIV+ subjects, nadir CD4 was the only HIV-specific factor associated with MIs (RR per 100 cells = 0.88; 95% CI: 0.81 to 0.96), whereas recent CD4 and HIV RNA, prior ART use, and duration of protease inhibitors and nonnucleoside reverse transcriptase inhibitors were not associated with MIs. Conclusion:HIV+ subjects with recent or nadir CD4 ≥500 cells per microliter had similar MI rates compared with HIV− subjects. Lower nadir CD4, in particular, seems to be independently associated with MIs. These results strengthen recommendations for earlier ART initiation.

Collaboration


Dive into the William Towner's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge