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Dive into the research topics where Mike Youle is active.

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Featured researches published by Mike Youle.


Hiv Medicine | 2005

British HIV Association guidelines for the treatment of HIV-1-infected adults with antiretroviral therapy 2008

B Gazzard; Jane Anderson; Abdel Babiker; Marta Boffito; Gary Brook; Gary Brough; Duncan Churchill; Ben Cromarty; Satyajit Das; Martin Fisher; Andrew Freedman; Anna Maria Geretti; Margaret Johnson; Saye Khoo; Clifford Leen; Devaki Nair; Barry Peters; Andrew N. Phillips; Deenan Pillay; Anton Pozniak; John P. Walsh; Ed Wilkins; Ian S. Williams; Matthew Williams; Mike Youle

This summary document is an update to the full British HIV Association (BHIVA) Treatment Guidelines published in HIV Medicine in July 2005 (Volume 6, Supplement 2). Only the ‘What to start with’ and ‘Treatment-experienced patients’ sections have been completely rewritten. The tables of recommendations (Tables 1–7) have also been updated to include new data. Please refer to the full guidelines for more information.


Nature Medicine | 2005

Efficacy of short-term monotherapy with maraviroc, a new CCR5 antagonist, in patients infected with HIV-1

Gerd Fätkenheuer; Anton Pozniak; Margaret Johnson; Andreas Plettenberg; Schlomo Staszewski; Andy I. M. Hoepelman; Michael S. Saag; Frank D. Goebel; Jürgen K. Rockstroh; Bruce J. Dezube; Timothy Mark Jenkins; Christine Medhurst; John F. Sullivan; Caroline E. Ridgway; Samantha Abel; Ian James; Mike Youle; Elna van der Ryst

We assessed the efficacy and safety of 10-d monotherapy with the orally administered CCR5 antagonist maraviroc in 63 HIV-1-positive individuals prescreened for the absence of CXCR4-using virus. Maximum reduction in viral load occurred at a median of 10–15 d, with a mean reduction of ≥1.6 log10 copies/ml at all twice daily doses ≥100 mg. These results provide proof of concept that CCR5 antagonism is a viable antiretroviral therapeutic approach.


Journal of Virology | 2006

Emergence of CXCR4-Using Human Immunodeficiency Virus Type 1 (HIV-1) Variants in a Minority of HIV-1-Infected Patients following Treatment with the CCR5 Antagonist Maraviroc Is from a Pretreatment CXCR4-Using Virus Reservoir

Mike Westby; Marilyn Lewis; Jeannette M. Whitcomb; Mike Youle; Anton Pozniak; Ian James; Timothy Mark Jenkins; Manos Perros; Elna van der Ryst

ABSTRACT Antagonists of the human immunodeficiency virus type 1 (HIV-1) coreceptor, CCR5, are being developed as the first anti-HIV agents acting on a host cell target. We monitored the coreceptor tropism of circulating virus, screened at baseline for coreceptor tropism, in 64 HIV-1-infected patients who received maraviroc (MVC, UK-427,857) as monotherapy for 10 days. Sixty-two patients harbored CCR5-tropic virus at baseline and had a posttreatment phenotype result. Circulating virus remained CCR5 tropic in 60/62 patients, 51 of whom experienced an HIV RNA reduction from baseline of >1 log10 copies/ml, indicating that CXCR4-using variants were not rapidly selected despite CCR5-specific drug pressure. In two patients, viral load declined during treatment and CXCR4-using virus was detected at day 11. No pretreatment factor predicted the emergence of CXCR4-tropic virus during maraviroc therapy in these two patients. Phylogenetic analysis of envelope (Env) clones from pre- and posttreatment time points indicated that the CXCR4-using variants probably emerged by outgrowth of a pretreatment CXCR4-using reservoir, rather than via coreceptor switch of a CCR5-tropic clone under selection pressure from maraviroc. Phylogenetic analysis was also performed on Env clones from a third patient harboring CXCR4-using virus prior to treatment. This patient was enrolled due to a sample labeling error. Although this patient experienced no overall reduction in viral load in response to treatment, the CCR5-tropic components of the circulating virus did appear to be suppressed while receiving maraviroc as monotherapy. Importantly, in all three patients, circulating virus reverted to predominantly CCR5 tropic following cessation of maraviroc.


AIDS | 2004

Late presenters in the era of highly active antiretroviral therapy: uptake of and responses to antiretroviral therapy

Caroline Sabin; Cj Smith; Helen Gumley; Gabrielle Murphy; Fiona Lampe; Andrew N. Phillips; Beth Prinz; Mike Youle; Margaret Johnson

Objectives: To investigate the characteristics and clinical, immunological and virological outcomes for individuals presenting for care with low CD4 cell counts. Methods: Individuals aged > 16 years presenting for care for the first time were identified between 1 January 1996 and 31 December 2002. Late presenters were those with CD4 cell count < 50×106 cells/l. Follow-up was until last contact, death or 31 December 2002. Results: Late presenters formed 15.3% (110) of the group; they were more likely to be female (35% versus 24%), heterosexual (53% versus 38%), and of Black-African ethnicity (39% versus 27%) than other individuals. Over a median follow-up of 2.5 years, 13% of late presenters died. Ninety-nine patients started antiretroviral treatment; Of the 11 patients who did not start antiretroviral treatment, eight died within 3 months of presentation. Among those starting treatment, 87 (87.9%) achieved a viral load < 400 copies/ml and median CD4 cell counts increased from 43 × 106 cells/l at 0–2 months after presentation to 204 × 106 cells/l at 1 year. Over the first year, 71 patients attended at least one outpatient visit (median, 4.5; range, 0–39), 21 attended at least one day case visit (median, 0; range, 0–15) and 49 were admitted as an inpatient (median, 0; range, 0–4). Conclusions: Those presenting for care with very low CD4 cell counts may make large demands on clinical resources, particularly over the first few months. While some patients do have a poor outcome on highly active antiretroviral therapy, many will benefit from this therapy and will experience good immunological and virological responses.


The Journal of Infectious Diseases | 2004

Factors Influencing Increases in CD4 Cell Counts of HIV-Positive Persons Receiving Long-Term Highly Active Antiretroviral Therapy

Cj Smith; Caroline Sabin; Mike Youle; Sabine Kinloch-de Loes; Fiona Lampe; Sara Madge; Ian Cropley; Margaret Johnson; Andrew N. Phillips

BACKGROUND Highly active antiretroviral therapy (HAART) results in an improvement in immunologic function. We sought to investigate the factors associated with increases in CD4 cell count among human immunodeficiency virus (HIV)-positive antiretroviral-naive patients starting HAART. METHODS Five hundred ninety-six subjects were followed for a median of 2.5 years (interquartile range, 1.0-4.0 years). Factors associated with changes in CD4 cell counts in the first 3 months of HAART and from 3 months onwards were analyzed. RESULTS After 6, 12, and 24 months of HAART, the median increases in CD4 cell counts were 114, 181, and 248 cells/mm3, respectively; 84%, 84%, and 80% of subjects had a virus load of <400 copies/mL during the same periods. White ethnicity, higher pre-HAART virus load, and lower pre-HAART CD4 and CD8 cell counts were associated with greater increases in CD4 cell counts during the first 3 months of HAART. From 3 months onward, a greater cumulative proportion of time spent with virus load <400 copies/mL was associated with a more favorable change in CD4 cell count (an average increase of 5.2 cells/mm3/year [95% confidence interval [CI], 3.8-6.7 cells/mm3/year] for each extra 10% cumulative time spent with a virus load <400 copies/mL) (P<.0001). For every 100 cells/mm3 higher in baseline CD4 cell count, the increase was 6 cells/mm3/year less (95% CI, 2-11 cells/mm3/year) (P=.02). Sex, risk group, age, and HAART regimen were not associated with increases in CD4 cell counts. CONCLUSIONS These findings emphasize the importance of maintaining virological suppression and suggest other factors that influence long-term CD4 cell response.


AIDS | 2001

Sexual dysfunction associated with protease inhibitor containing highly active antiretroviral treatment

Ward Schrooten; Robert Colebunders; Mike Youle; Geert Molenberghs; Nikos Dedes; Gunvor Koitz; Renato Finazzi; Inge de Mey; Eric Florence; C Dreezen

BackgroundA high proportion of individuals receiving highly active antiretroviral treatment (HAART) complain of sexual dysfunction (SD), encompassing a lack of desire or erectile dysfunction. ObjectiveTo determine whether SD was associated with particular components of the HAART regimens and to identify risk factors for the development of SD in patients on HAART. MethodsA survey among patients with HIV infection using an anonymous questionnaire was conducted in 10 European countries between December 1998 and December 1999. A total of 904 individuals currently receiving antiretroviral agents were included in the analyses. ResultsA decrease in sexual interest was significantly more frequently reported by subjects (men and women) using HAART containing protease inhibitors (PI) (308/766, 40%), compared with PI-naive patients (22/138, 16%; OR 3.55; 95% CI 2.15–5.89). In addition, a significantly larger number of PI-experienced men reported a decrease in sexual potency (216/628, 34%) compared with PI-naive men (12/99, 12%; OR 2.56; 95% CI 1.33–5.03). In multivariate analyses the following factors were associated with a decrease in sexual interest: a current PI-containing regimen, a history of a PI regimen, symptomatic HIV infection, age and homosexual contact as HIV transmission mode. Factors associated with a decrease in sexual potency were: current use of a PI-containing regimen, symptomatic HIV disease, age and the use of tranquillisers. ConclusionSD appears to be a common side-effect of HAART regimens containing a PI. The potential association between SD and other side-effects of HAART, such as lipodystrophy syndrome and neuropathy, should be investigated further.


AIDS | 2006

Deaths in the era of HAART: contribution of late presentation, treatment exposure, resistance and abnormal laboratory markers

Caroline Sabin; Cj Smith; Mike Youle; Fiona Lampe; Di Robertson Bell; Dewi Puradiredja; Marc Lipman; Sanjay Bhagani; Andrew N. Phillips; Margaret Johnson

Objectives:To describe the characteristics of deaths that occur among HIV-positive individuals in the HAART era. Design:Observational database. Methods:Deaths were reviewed that occurred among HIV-positive individuals seen at the Royal Free Hospital, London between January 1998 and December 2003. Results:Over the study period, there were 121 deaths; death rates declined from approximately 2.0/100 person-years of follow-up in 1998–2000 to approximately 1.0/100 person-years of follow-up in 2001–2003. Approximately one half of deaths (45.5%) were from AIDS-related causes and 74 deaths (61.2%) occurred in individuals who had received HAART: patients had been exposed to a median of seven (range 2–14) antiretroviral drugs and two-fifths had started treatment in the pre-HAART era. Another 15 patients had received only non-HAART treatment regimens prior to death. The median pre-death CD4 cell counts were 68 and 167 cells/μl among those who had and had not received HAART; 23 (31.1%) and 4 (8.5%) had HIV RNA < 400 copies/ml, respectively. Of the patients exposed to HAART for at least 6 months and who experienced viral rebound, information was available on resistance for 26 (21.5% of the total deaths) and 19 of those tested had at least one resistance mutation (median 5, range, 1–16). Conclusions:While mortality rates among HIV-infected individuals at our centre have fallen since 1988, the deaths that do now occur are more diverse and are the result of a number of factors, including late presentation, delayed uptake of HAART and the previous use of treatment combinations that are now viewed as suboptimal.


Hiv Medicine | 1999

Chronic erosive herpes simplex virus infection of the penis, a possible immune reconstitution disease

Fox Pa; Barton Se; Francis N; Mike Youle; Henderson Dc; D Pillay; Margaret Johnson; Fearfield L; B Gazzard; Bunker Cb

Objective To report a novel clinical presentation: a chronic erosive herpes simplex virus (HSV) infection of the penis which developed in AIDS patients following the commencement of highly active antiretroviral therapy (HAART). The lesions were unresponsive to antiviral treatments which had previously been effective, and this could not be accounted for in terms of increased antiviral resistance.


BMJ | 2005

Treatment exhaustion of highly active antiretroviral therapy (HAART) among individuals infected with HIV in the United Kingdom: multicentre cohort study

Caroline Sabin; Teresa Hill; Fiona Lampe; Ryanne Matthias; Sanjay Bhagani; Richard Gilson; Mike Youle; Margaret Johnson; Martin Fisher; George Scullard; Philippa Easterbrook; Brian Gazzard; Andrew N. Phillips

Abstract Objectives To investigate whether there is evidence that an increasing proportion of HIV infected patients is starting to experience increases in viral load and decreases in CD4 cell count that are consistent with exhaustion of available treatment options. Design Multicentre cohort study. Setting Six large HIV treatment centres in southeast England. Participants All individuals seen for care between 1 January 1996 and 31 December 2002. Main outcome measures Exposure to individual antiretroviral drugs and drug classes, CD4 count, plasma HIV RNA burden. Results Information is available on 16 593 individuals (13 378 (80.6%) male patients, 10 340 (62.3%) infected via homosexual or bisexual sex, 4426 (26.7%) infected via heterosexual sex, median age 34 years). Overall, 10 207 of the 16 593 patients (61.5%) have been exposed to any antiretroviral therapy. This proportion increased from 41.2% of patients under follow up at the end of 1996 to 71.3% of those under follow up in 2002. The median CD4 count and HIV RNA burden of patients under follow up in each year changed from 270 cells/mm3 and 4.34 log10 copies/ml in 1996 to 408 cells/mm3 and 1.89 log10 copies/ml, respectively, in 2002. By 2002, 3060 (38%) of patients who had ever been treated with antiretroviral therapy had experienced all three main classes. Of these, around one quarter had evidence of “viral load failure” with all these three classes. Patients with three class failure were more likely to have an HIV RNA burden > 2.7 log10 copies/ml and a CD4 count < 200 cells/mm3. Conclusions The proportion of individuals with HIV infection in the United Kingdom who have been treated has increased gradually over time. A substantial proportion of these patients seem to be in danger of exhausting their options for antiretroviral treatment. New drugs with low toxicity, which are not associated with cross resistance to existing drugs, are urgently needed for such patients.


Hiv Clinical Trials | 2001

Health-Related Quality of Life in Individuals Infected with HIV in the Era of HAART

Alexander H. Miners; Caroline Sabin; Amanda Mocroft; Mike Youle; Martin Fisher; Margaret Johnson

Abstract Purpose: To compare health-related quality of life (HR-QOL) in individuals infected with HIV to general population levels and to assess the relationship between HR-QOL and markers of disease progression in the era of highly active antiretroviral therapy (HAART). Method: This was a cross-sectional questionnaire-based study. This study included 154 individuals at least 18 years old with HIV who either were attending a London hospital or were visited by a community team in Brighton. Study participants were asked to complete two HR-QOL questionnaires. This study used HR-QOL, as measured using the Medical Outcome Study HIV Health Survey (MOS-HIV) and EuroQoL self-report (EQ-5D) questionnaires, as the main outcome measure. Responses on the EQ-5D were compared with a published general population data set. The relationships between scores on the MOS-HIV and EQ-5D questionnaires and a number of independent variables including CD4 count and viral load were also assessed. Results: Each analysis was based on the results of at least 128 questionnaires. The mean MOS-HIV mental and physical component scores were 43.2 (SD = 12.2) and 41.8 (SD = 13.2), respectively. After adjusting for differences in age and gender, it was shown that individuals with HIV reported significantly lower EQ-5Dutility ( p = .0001) and EQ-5DVAS ( p = .0001) compared with the general population. However, further analysis revealed few significant associations between markers of disease progression and HR-QOL. Conclusion: Individuals with HIV generally recorded significantly lower HR-QOL compared with the general population. Thus, prevention of further transmissions of the virus is still likely to prevent significant morbidity losses in addition to mortality losses, despite the availability of HAART. However, disease progression as measured is not clearly related to further reductions in HR-QOL.

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Margaret Johnson

Royal Free London NHS Foundation Trust

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Fiona Lampe

University College London

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Caroline Sabin

University College London

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Cj Smith

University College London

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Anton Pozniak

Chelsea and Westminster Hospital NHS Foundation Trust

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