In-vitro tipranavir susceptibility of HIV-1 isolates with reduced susceptibility to other protease inhibitors

Targeting PRSS23 with tipranavir induces gastric cancer stem cell apoptosis and inhibits growth of gastric cancer via the MKK3/p38 MAPK-IL24 pathway

Gastric cancer stem cells (GCSCs) contribute to the refractory features of gastric cancer (GC) and are responsible for metastasis, relapse, and drug resistance. The key factors drive GCSC function and affect the clinical outcome of GC patients remain poorly understood. PRSS23 is a novel serine protease that is significantly up-regulated in several types of cancers and cancer stem cells, and related to tumor progression and drug resistance. In this study, we investigated the role of PRSS23 in GCSCs as well as the mechanism by which PRSS23 regulated the GCSC functions. We demonstrated that PRSS23 was critical for sustaining GCSC survival. By screening a collection of human immunodeficiency virus (HIV) protease inhibitors (PIs), we identified tipranavir as a PRSS23-targeting drug, which effectively killed both GCSC and GC cell lines (its IC50 values were 4.7 and 6.4 μM in GCSC1 cells and GCSC2 cells, respectively). Administration of tipranavir (25 mg·kg-1·d-1, i.p., for 8 days) in GCSC-derived xenograft mice markedly inhibited the growth of subcutaneous GCSC tumors without apparent toxicity. In contrast, combined treatment with 5-FU plus cisplatin did not affect the tumor growth but causing significant weight loss. Furthermore, we revealed that tipranavir induced GCSC cell apoptosis by suppressing PRSS23 expression, releasing MKK3 from the PRSS23/MKK3 complex to activate p38 MAPK, and thereby activating the IL24-mediated Bax/Bak mitochondrial apoptotic pathway. In addition, tipranavir was found to kill other types of cancer cell lines and drug-resistant cell lines. Collectively, this study demonstrates that by targeting both GCSCs and GC cells, tipranavir is a promising anti-cancer drug, and the clinical development of tipranavir or other drugs specifically targeting the PRSS23/MKK3/p38MAPK-IL24 mitochondrial apoptotic pathway may offer an effective approach to combat gastric and other cancers.

Thirty Years of Research on Gay Men and HIV Prevention in France: A Narrative Review of the Literature

Research on homosexuality and HIV/AIDS in the social sciences has evolved into a vast and multiform field of study since the beginning of the epidemic in the Global North. Studies from France in this domain have remained relatively unknown at the international level. This article offers a narrative review of publications that resulted from research on homosexuality and HIV/AIDS, from 1985 to 2016. It offers an analysis of how the constitution of a field of research conditions the ways scientific questions are asked (and answered). This epistemological concern is addressed through a sociohistorical contextualization of the main issues surrounding prevention and how they have been addressed by researchers in France. A review of French publications on HIV prevention among gay men reveals certain specificities. In terms of the social science disciplines, psychology and psychoanalysis are much less present in this domain, whereas epidemiology, sociology, and anthropology are the most represented. The works analyzed in this article also reveal the circulation and local adaptations of risk categories imported from the English-speaking world, such as "relapse" and "bareback." Regardless, research on HIV prevention in France largely evolved contemporaneously in the same way that it did elsewhere.

Tipranavir: A Protease Inhibitor for HIV Salvage Therapy

Objective:

TO review the efficacy, safety, pharmacology, virology, pharmacokinetics, and resistance of the nonpeptidic protease inhibitor (PI) tipranavir.

Data Sources and Study Selection:

A PubMed search (1966–February 2006) was conducted using the key words tipranavir or PNU-140690, with the limitation of English-language reports. Pharmacokinetic and randomized clinical trials originating from major HIV conferences, such as the Conference on Retroviruses and Opportunistic Infections, International AIDS Society, European AIDS Conference, and Interscience Conference on Antimicrobial Agents and Chemotherapy, published only in abstract form, from 2000 to February 2006, were reviewed for relevance and included in this review.

Data Synthesis:

Phase III studies have shown that tipranavir is effective in the treatment of PI-resistant HIV compared with other PI-containing regimens. Adverse effects associated with tipranavir/ritonavir therapy include gastrointestinal reactions, hepatotoxicity, and elevations in cholesterol and triglyceride levels. Resistance data suggest that tipranavir/ritonavir should be reserved for salvage therapy in antiretroviral-experienced patients who have previously failed standard PI therapies. The potential for hepatotoxicity and drug interactions and the expense of tipranavir due to required ritonavir boosting may limit its widespread use.

Conclusions:

Tipranavir/ritonavir is an essential addition to the antiretroviral armamentarium for HIV-infected patients with limited treatment options.

Pharmacokinetic Characterization of Different Dose Combinations of Coadministered Tipranavir and Ritonavir in Healthy Volunteers

PURPOSE

To characterize the steady-state pharmacokinetic combination of the nonpeptidic protease inhibitor tipranavir (TPV) with ritonavir (RTV) in 95 healthy adult volunteers, a phase 1, single-center, open-label, randomized, parallel-group trial was conducted.

METHOD

Participants received 250-mg self-emulsifying drug delivery system (SEDDS) capsules of TPV at doses between 250 mg and 1250 mg twice daily for 11 days, then received one or two RTV 100-mg SEDDS capsules, in addition to the TPV capsules, for the next 21 days.

RESULTS

Coadministration of TPV and RTV (TPV/r) resulted in a greater than 20-fold increase in steady-state TPV trough concentrations (Cssmin) as compared with TPV at steady state alone. Mean TPV Cssmin was above a preliminary target threshold of 20 microM with all but one of the RTV-boosted doses; without boosting, none of the TPV-alone doses exceeded the threshold. The average steady-state Cssmin for TPV 500 mg and 750 mg with RTV 100 mg or 200 mg were 20 to 57 times the protein-adjusted TPV IC90R49\CCR418569) for protease inhibitor-resistant HIV-1. An erythromycin breath test, a surrogate marker for cytochrome P450 isoenzyme 3A4 activity, indicated that all TPV/r combinations given provided net inhibition of this isoenzyme. The most frequent treatment-related adverse events were mild gastrointestinal symptoms.

CONCLUSION

This phase 1 study demonstrated that RTV-boosted TPV achieves concentrations that are expected to be effective in treating drug-experienced patients.

How Many HIV infections may be averted by targeting primary infection in men who have sex with men? Quantification of changes in transmission-risk behavior, using an individual-based model

In the United Kingdom, human immunodeficiency virus (HIV) transmission among men who have sex with men (MSM) is not under control, despite readily available treatment, highlighting the need to design a cost-effective combination prevention package. MSM report significantly reduced transmission risk behavior following HIV diagnosis. To assess the effectiveness of HIV diagnosis in averting transmission during highly infectious primary HIV infection (PHI), we developed a stochastic individual-based model to calculate the number of HIV-transmission events expected to occur from a cohort of recently infected MSM with and those without the behavior changes reported after diagnosis. The model incorporates different types of sex acts, incorporates condom use, and distinguishes between regular and casual sex partners. The impact on transmission in the 3 months after infection depends on PHI duration and testing frequency. If PHI lasts for 3 months and testing is performed monthly, then behavior changes after diagnosis would have reduced estimated transmission events by 49%–52%, from 31–45 to 15–23 events; a shorter duration of PHI and/or a lower testing frequency reduces the number of infections averted. Diagnosing HIV during PHI can markedly reduce transmission by changing transmission-risk behavior. Because of the high infectivity but short duration of PHI, even short-term behavior change can significantly reduce transmission. Our quantification of the number of infections averted is an essential component of assessment of the cost-effectiveness of strategies to increase detection and diagnoses of PHI.

Beyond prevention: containment rhetoric in the case of bug chasing

Bug chasing, the practice of pursuing HIV positive sexual partners in order to acquire HIV, presents multiple dilemmas for health affiliates in terms of how to address discourses and practices that challenge widely held beliefs about health and medicine. In order to examine how researchers respond to controversial counterpublic rhetorics, this essay chronicles the construction of "bug chasing" in published social science literature. Guided by a theory of containment rhetoric, I analyze how bug chasers are configured in the language of social science used to describe and explain them. I find that social scientific coverage of bug chasing often addresses the behavior using a recipe of rhetorical containment: first, authors gaze upon bug chasers via distanced descriptions of the community; second, authors characterize the behavior as exhibiting an idealistic naiveté; and, third, authors stress the inconceivable, and therefore reproachable, sacrifice that bug chasing ultimately demands of its onlookers and participants. In closing, I evaluate the consequences of this containment rhetoric and offer three rhetorical maneuvers to aid future scholarship that examines the discourses and communities that counter dominant health ideologies.

Practical Perspectives on the Use of Tipranavir in Combination With Other Medications: Lessons Learned From Pharmacokinetic Studies

Drug-drug interactions are a major practical concern for physicians treating human immunodeficiency virus (HIV) because of the many medications that HIV-positive patients must take. Pharmacokinetic drug interactions can occur at different levels (absorption, distribution, metabolism, excretion) and are difficult to predict. Of all the processes that give rise to drug interactions, metabolism by cytochrome P450 (CYP3A) is the most frequent. Moreover, medications prescribed to HIV-positive patients may also be CYP3A inhibitors and inducers: Tipranavir, in the absence of ritonavir, is a CYP3A inducer, and ritonavir is a CYP3A inhibitor. Fortunately, the drug interactions between tipranavir coadministered with ritonavir and other antiretroviral medications or with other medications commonly used in HIV therapy are well characterized. This review summarizes the pharmacokinetic interactions between tipranavir/ritonavir and 11 other antiretroviral medications and between tipranavir/ritonavir and drugs used to treat opportunistic infections such as fungal infections, antiretroviral-treatment-related conditions such as hyperlipidemia, and side effects such as diarrhea.

Sexual orientation disparities in sexually transmitted infections: examining the intersection between sexual identity and sexual behavior

The terms MSM (men who have sex with men) and WSW (women who have sex with women) have been used with increasing frequency in the public health literature to examine sexual orientation disparities in sexual health. These categories, however, do not allow researchers to examine potential differences in sexually transmitted infection (STI) risk by sexual orientation identity. Using data from the National Longitudinal Survey of Adolescent Health, this study investigated the relationship between self-reported STIs and both sexual orientation identity and sexual behaviors. Additionally, this study examined the mediating role of victimization and STI risk behaviors on the relationship between sexual orientation and self-reported STIs. STI risk was found to be elevated among heterosexual-WSW and bisexual women, whether they reported same-sex partners or not, whereas gay-identified WSW were less likely to report an STI compared to heterosexual women with opposite sex relationships only. Among males, heterosexual-identified MSM did not have a greater likelihood of reporting an STI diagnosis; rather, STI risk was concentrated among gay and bisexual identified men who reported both male and female sexual partners. STI risk behaviors mediated the STI disparities among both males and females, and victimization partially mediated STI disparities among female participants. These results suggest that relying solely on behavior-based categories, such as MSM and WSW, may mischaracterize STI disparities by sexual orientation.

Loss of the protease dimerization inhibition activity of tipranavir (TPV) and its association with the acquisition of resistance to TPV by HIV-1

Tipranavir (TPV), a protease inhibitor (PI) inhibiting the enzymatic activity and dimerization of HIV-1 protease, exerts potent activity against multi-PI-resistant HIV-1 isolates. When a mixture of 11 multi-PI-resistant (but TPV-sensitive) clinical isolates (HIV(11MIX)), which included HIV(B) and HIV(C), was selected against TPV, HIV(11MIX) rapidly (by 10 passages [HIV(11MIX)(P10)]) acquired high-level TPV resistance and replicated at high concentrations of TPV. HIV(11MIX)(P10) contained various amino acid substitutions, including I54V and V82T. The intermolecular FRET-based HIV-1 expression assay revealed that TPV's dimerization inhibition activity against cloned HIV(B) (cHIV(B)) was substantially compromised. The introduction of I54V/V82T into wild-type cHIV(NL4-3) (cHIV(NL4-3(I54V/V82T))) did not block TPV's dimerization inhibition or confer TPV resistance. However, the introduction of I54V/V82T into cHIV(B) (cHIV(B)(I54V/V82T)) compromised TPV's dimerization inhibition and cHIV(B)(I54V/V82T) proved to be significantly TPV resistant. L24M was responsible for TPV resistance with the cHIV(C) genetic background. The introduction of L24M into cHIV(NL4-3) (cHIV(NL4-3(L24M))) interfered with TPV's dimerization inhibition, while L24M increased HIV-1's susceptibility to TPV with the HIV(NL4-3) genetic background. When selected with TPV, cHIV(NL4-3(I54V/V82T)) most readily developed TPV resistance and acquired E34D, which compromised TPV's dimerization inhibition with the HIV(NL4-3) genetic background. The present data demonstrate that certain amino acid substitutions compromise TPV's dimerization inhibition and confer TPV resistance, although the loss of TPV's dimerization inhibition is not always associated with significantly increased TPV resistance. The findings that TPV's dimerization inhibition is compromised with one or two amino acid substitutions may explain at least in part why the genetic barrier of TPV against HIV-1's development of TPV resistance is relatively low compared to that of darunavir.

The contribution of antenatal care to the coverage and correlates of HIV testing among adults in Zimbabwe 2005-06

Expanding the availability, utilization and coverage of HIV testing services is a critical step towards primary prevention and successful delivery of antiretroviral therapy (ART) in Zimbabwe. We used data from the Zimbabwe Demographic and Health Survey (2005-2006) to examine the coverage and correlates of recent HIV testing (HIV testing <24 months preceding the survey) among HIV-positive and HIV-negative adults. We estimated the relative contribution of HIV testing in both the antenatal care (ANC) setting and non-ANC settings. Uptake of recent HIV testing was 14.4% among women and 11.1% among men, with HIV testing in ANC accounting for 42.3% and 10.3% of all recent testing among women and men, respectively. In the multivariate analyses, recent pregnancies and being aware of ART were independent correlates after controlling for demographic and socioeconomic variables. HIV testing in ANC was an important contributor to HIV testing coverage in Zimbabwe by reaching not only pregnant women but also their partners.

The relationship between socioeconomic factors, wellbeing, and homosexuality in the theatrical profession

This article relates to the theory suggesting that there is a prevalence of male homosexuality within the theatrical profession that can be explained through male performers becoming homosexual due to their low socioeconomic position. In a questionnaire-based study, the socioeconomic status (SES) is measured of 121 homosexual performers who considered themselves to have been heterosexual at the time of joining the profession, and results are compared with a control group of 121 heterosexual male performers. The experimental group was chosen in this way due to the suggestion of the hypothesis that the change in sexual orientation occurs after the man begins performing professionally. Results were not significant and little difference was noted in any of the parameters of SES, including annual earnings and home ownership. However, a marginal though insignificant increase in SES was noted in the experimental group of homosexual men. Consequently, existing theories for homosexuality and possible reasons for the high prevalence within the performing profession are discussed; the notions of adult performing and creativity being extensions of childhood gender atypical behavior are considered and possible links between sexual orientation and these traits. Elements of genetic heritability of homosexuality are likewise implicated.

Behavioural surveillance among gay men in Australia: methods, findings and policy implications for the prevention of HIV and other sexually transmissible infections

BACKGROUND

The Australian HIV and sexually transmissible infection (STI) behavioural surveillance system (the repeated cross-sectional Gay Community Periodic Surveys, GCPS) has been conducted since 1998 and covers six main Australian jurisdictions. In this paper, we review its history and methodology, and the available indicators, their trends and their use.

METHODS

We describe the design and history of GCPS. For analyses of indicators, we use Pearson's χ²-test and test for trend where appropriate.

RESULTS

About 90% of gay men in Australia have been tested for HIV (60% to 70% of men who were not HIV-positive) have been tested as recommended in the preceding 12 months. STI testing levels (≈ 70% in the preceding 12 months) are high, but remain insufficient for STI prevention. In general, unprotected anal intercourse with regular (UAIR) and casual (UAIC) sex partners has increased over time. The prevalence and increasing trends in UAIR were similar across jurisdictions (P-trend <0.01), while trends in UAIC differed across the states: during 2001-08, UAIC declined in NSW (P-trend <0.01) and increased elsewhere (P-trend <0.01). Trends in UAIC were associated with HIV diagnoses.

CONCLUSION

This review of the design, implementation and findings of the Australian HIV/STI behavioural surveillance highlights important lessons for HIV/STI behavioural surveillance among homosexual men, particularly the need for consistent data collection over time and across jurisdictions. Investment in systematic behavioural surveillance appears to result in a better understanding of the HIV epidemic, the availability of a warning system and a better targeted HIV prevention strategy.

Ritonavir-boosted protease inhibitors in HIV therapy

The advent of combination antiretroviral therapy has led to significant improvement in the care of HIV-infected patients. Originally designed as a protease inhibitor (PI), ritonavir is currently exclusively used as a pharmacokinetic enhancer of other protease inhibitors, predominantly due to ritonavir's potent inhibition of the cytochrome P450 3A4 isoenzyme. Ritonavir-boosting of PIs decrease pill burden and frequency of dosing. Boosted PIs are recommended for first-line therapy in treatment and play a key role in the management of treatment-experienced patients. Potential problems associated with PIs include metabolic abnormalities (e.g. dyslipidemia), increased cardiovascular risk, and drug interactions.

Sexual health, HIV, and sexually transmitted infections among gay, bisexual, and other men who have sex with men in the United States

The sexual health of gay, bisexual, and other men who have sex with men (MSM) in the United States is not getting better despite considerable social, political and human rights advances. Instead of improving, HIV and sexually transmitted infections (STIs) remain disproportionately high among MSM and have been increasing for almost two decades. The disproportionate and worsening burden of HIV and other STIs among MSM requires an urgent re-assessment of what we have been doing as a nation to reduce these infections, how we have been doing it, and the scale of our efforts. A sexual health approach has the potential to improve our understanding of MSM's sexual behavior and relationships, reduce HIV and STI incidence, and improve the health and well-being of MSM.

Male injecting drug users in the Deep South: bisexual behaviour is a marker for elevated HIV risk

This study determined whether bisexual male injecting drug users (IDUs) as compared with heterosexual IDUs were more likely to engage in HIV-associated risk behaviours. Respondent-driven sampling was employed to recruit a sample of 382 male IDUs residing in the southeastern USA. Data were collected in face-to-face interviews. Weighted analyses showed that bisexual IDUs in the past 12 months were 4.6 times as likely to share needles and 3.5 times as likely to share a cooker; having multiple female sexual partners and trading money or drugs for sex with women were marginally significant. Bisexual IDUs were 10 times as likely to self-report HIV. Male IDUs, who engage in bisexual behaviour, are also engaging in HIV-associated drug and to some degree sexual-risk behaviours with women more so than heterosexual IDUs. Their higher prevalence of HIV infection coupled with their risk behaviours place themselves and other IDUs at heightened risk of both acquiring and transmitting HIV.

P-glycoprotein related drug interactions: clinical importance and a consideration of disease states

IMPORTANCE OF THE FIELD

P-glycoprotein (P-gp) is the most characterized drug transporter in terms of its clinical relevance for pharmacokinetic disposition and interaction with other medicines. Clinically significant P-gp related drug interactions appear restricted to digoxin. P-gp may act as a major barrier to current and effective drug treatment in a number of diseases including cancer, AIDS, Alzheimer's and epilepsy due to its expression in tumors, lymphocytes, cell membranes of brain capillaries and the choroid plexus.

AREAS COVERED IN THIS REVIEW

This review summarizes the current understanding of P-gp structure/function, clinical importance of P-gp related drug interactions and the modulatory role this transporter may contribute towards drug efficacy in disease states such as cancer, AIDS, Alzheimer's and epilepsy.

WHAT THE READER WILL GAIN

The reader will gain an understanding that the clinical relevance of P-gp in drug interactions is limited. In certain disease states, P-gp in barrier tissues can modulate changes in regional distribution.

TAKE HOME MESSAGE

P-gp inhibition in isolation will not result in clinically important alterations in systemic exposure; however, P-gp transport may be of significance in barrier tissues (tumors, lymphocytes, brain) resulting in attenuated efficacy.

Risk behaviors and psychosocial stressors in the new york city house ball community: a comparison of men and transgender women who have sex with men

The New York City House Ball community consists of social networks of racial/ethnic minority gay, lesbian or bisexual men and women, and transgender persons. HIV seroprevalence and interview data were obtained from a sample of community members to identify statistical differences in HIV prevalence, risk behavior, and psychosocial stressors between men who have sex with men (MSM) and transgender women. Of 301 MSM and 60 transgender women, 20% were HIV-infected and 73% were unaware of their infection, but rates did not differ by gender. Risk behavior and stressors were common in both groups, but transgender women were more likely to report exchange sex, stigmatization, and stressful life events. High rates of risk behavior and HIV in this special community warrant relevant HIV testing and prevention services. Transgender women in the community may be at even greater risk for HIV infection due to behaviors compounded by substantial psychosocial stressors.

HIV vulnerability of men who have sex with men in developing countries: Horizons studies, 2001-2008

While male-to-male sexual behavior has been recognized as a primary risk factor for human immunodeficiency virus (HIV), research targeting men who have sex with men (MSM) in less-developed countries has been limited due to high levels of stigma and discrimination. In response, the Population Council's Horizons Program began implementing research activities in Africa and South America beginning in 2001, with the objectives of gathering information on MSM sexual risk behaviors, evaluating HIV-prevention programs, and informing HIV policy makers. The results of this nearly decade-long program are presented in this article as a summary of the Horizons MSM studies in Africa (Senegal and Kenya) and Latin America (Brazil and Paraguay), and include research methodologies, study findings, and interventions evaluated. We also discuss future directions and approaches for HIV research among MSM in developing countries.

Clinical management of treatment-experienced, HIV/AIDS patients in the combination antiretroviral therapy era

Despite the success of combination antiretroviral therapy (ART) in improving clinical outcomes, treatment failure remains a significant challenge, particularly for highly treatment-experienced patients. This review evaluates current issues in the management of HIV-infected, treatment-experienced patients. It may provide guidance in selecting active, tolerable drug combinations that promote a reasonable quality of life, full adherence and a durable treatment response. Current treatment guidelines and clinical trial data were reviewed to identify reasons for treatment failure and to summarize therapy options for treatment-experienced and highly treatment-experienced patients. Current treatment options include nucleoside reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs), and inhibitors of viral fusion, entry and integration. The use of NRTIs may be limited by resistance and short- and long-term toxicities. Resistance has restricted the NNRTI class with cross-resistance preventing their sequential use. Etravirine, a next-generation NNRTI, however, demonstrates effective virological suppression in patients with baseline NNRTI resistance. Boosted PIs are key components of ART for treatment-experienced patients. The newer boosted PIs tipranavir and darunavir have demonstrated impressive activity in patients with resistance to NRTIs, NNRTIs and PIs, as well as in less treatment-experienced patients for darunavir. The fusion inhibitor enfuvirtide has demonstrated efficacy in heavily treatment-experienced patients, although injection-site reactions can be problematical. The recently approved integrase inhibitor raltegravir has also shown impressive potency and tolerability in highly treatment-experienced patients. Finally, the entry inhibitor maraviroc has also been approved recently, although its use is somewhat limited by the need for HIV tropism testing. The availability of potent next-generation PIs, NNRTIs, integrase and entry-inhibitors may offer improved therapy for treatment-experienced patients, including those with multiresistant virus. These new drugs may reduce HIV immunological and clinical progression and in doing so may also reduce treatment costs.

Differential HIV risk behavior among men who have sex with men seeking health-related mobile van services at diverse gay-specific venues

Distinguishing between gay venues may provide important information to better understand patterns of environmental influence and HIV/STI behavioral risk among MSM. Massachusetts MSM accessing State Health Department mobile van services (n = 214) at Gay Pride events, bars/clubs, and private safer sex parties completed a one-time, cross-sectional survey via ACASI. In the past 12 months, private safer sex party attendees reported a higher mean number of anonymous partners, were more likely to report meeting sex partners via the Internet, and were more likely to report sex while drunk; in logistic regression analyses, they were less likely to report both unprotected insertive and receptive anal sex in the past year relative to men from other venues. Private safer sex parties may represent a strategy used by some MSM to reduce HIV/STI risk. Differentiating risk behavior by venue type provides valuable information with which to effectively target interventions to reach MSM at greatest risk.

"Contagious love": a qualitative study of the couple relationships of ten AIDS carriers

The qualitative study in this article portrays the couple relationship among AIDS carriers, based on Sternberg's triangular love theory (involving domains of intimacy, passion and commitment). The central study hypothesis is that certain components of the Sternberg model will be more significant than others among the AIDS carrier population. The study was conducted on ten AIDS carriers aged 21-37 who had experienced a couple relationship. Six men and four women participated; most of them were in a romantic couple relationship of homosexual orientation.

The interviewees answered a questionnaire that included the three domains-- intimacy, passion and commitment--in the personal interview technique. The interview focused on interviewee's attitude towards his/her relationship with a partner, as he/she understood it. The findings of the study focus on relevant content that was gathered from the interviews and these portray a limited view of couple patterns in the world of AIDS carriers. The study reveals two major findings regarding the carrier's desires: On the one hand, the carrier describes a powerful need for a stable, permanent relationship--from the diagnosis of AIDS and throughout the subsequent years. On the other hand, the carrier also expresses powerful sexual desires that are not necessarily limited to a permanent partner. Thus passion is the dominant among the three domains.

The intimacy domain is mainly affected by disclosure of the disease and the joint coping that follows.

The findings are discussed in the context of the romantic internalized model theory and Sternberg's triangular love theory.

Integrating professional and folk models of HIV risk: YMSM's perceptions of high-risk sex

Risks associated with HIV are well documented in research literature. Although a great deal has been written about high-risk sex, little research has been conducted to examine how young men who have sex with men (YMSM) perceive and define high-risk sexual behavior. In this study, we compare the "professional" and "folk" models of HIV risk based on YMSM's understanding of high-risk sex and where and how they gathered their understanding of HIV risk behaviors. The findings reported here emerged from the quantitative and qualitative interviews from the Healthy Young Men's Study, a longitudinal study examining risk and protective factors for substance use and sexual risk among an ethnically diverse sample of YMSM. Findings are discussed in relation to framing how service providers and others can increase YMSM's knowledge of sexual behavior and help them build solid foundations of sexual health education to protect them from sexually transmitted infections and HIV.

Biotransformation and mass balance of tipranavir, a nonpeptidic protease inhibitor, when co-administered with ritonavir in Sprague-Dawley rats

In this study, tipranavir (TPV) biotransformation and disposition when co-administered with ritonavir (RTV) were characterized in Sprague-Dawley rats. Rats were administered a single intravenous (5 mg kg(-1)) or oral (10 mg kg(-1)) dose of [(14)C]TPV with co-administration of RTV (10 mg kg(-1)). Blood, urine, faeces and bile samples were collected at specified time-points over a period of 168 h. Absorption of TPV-related radioactivity ranged from 53.2-59.6%. Faecal excretion was on average 86.7% and 82.4% (intravenous) and 75.0% and 82.0% (oral) of dosed radioactivity in males and females, respectively. Urinary excretion was on average 4.06% and 6.73% (intravenous) and 9.71% and 8.28% (oral) of dosed radioactivity in males and females, respectively. In bile-duct-cannulated rats, 39.8% of the dose was recovered in bile. After oral administration, unchanged TPV accounted for the majority of the radioactivity in plasma (85.7-96.3%), faeces (71.8-80.1%) and urine (33.3-62.3%). The most abundant metabolite in faeces was an oxidation metabolite R-2 (5.9-7.4% of faecal radioactivity, 4.4-6.1% of dose). In urine, no single metabolite was found to be significant, and comprised <1% of dose. TPV when co-administered with RTV to rats was mainly excreted in feces via bile and the parent compound was the major component in plasma and faeces.

Health-Related Quality of Life and Tolerability in Treatment-Experienced HIV-1–Infected Patients on Tipranavir versus Comparator Regimens

Background

Antiretroviral therapy including tipranavir boosted with ritonavir (TPV/r) has shown superior viral suppression and immunological response compared with comparator ritonavir-boosted protease inhibitor (CPI/r) regimens in treatment-experienced HIV-1-infected patients. This study assesses the influence of adverse events (AEs) on health-related quality of life (HRQOL) and change in HRQOL in patients treated with TPV/r versus CPI/r regimens.

Methods

Changes in HRQOL over 48 weeks were assessed using Medical Outcomes Study HIV Health Survey (MOS-HIV) data combined from two randomized, open-label, Phase III studies (RESIST-1 and RESIST-2). Generalized estimating equations (GEE) were used to compare physical health and mental health summary scores and 10 subscale scores, and to compare scores of patients with and without AEs. To compare AE incidences in the two treatment groups, AEs were exposure-adjusted.

Results

There were 984 patients in the HRQOL analysis. AE occurrence and severity resulted in significantly lower MOS-HIV scores across both treatment arms ( P<0.05). Overall incidence of AEs was higher in the CPI/r versus TPV/r group (562.8 versus 514.4 per 100 patient-exposure years); treatment-related AEs were more frequent in the TPV/r group (75.0 versus 56.6 per 100 patient-exposure years). HRQOL was maintained in patients on TPV/r over 48 weeks of treatment across all summary and subscale scores. Compared with CPI/r, TPV/r was associated with a significant but small (sd<0.2) improvement in pain scores (+4.8 points; P<0.05).

Conclusions

HRQOL was maintained across both summary and all subscale scores from baseline to 48 weeks in the TPV/r and CPI/r treatment arms, despite the incidence of treatment-related AEs.

Tipranavir (TPV) genotypic inhibitory quotient predicts virological response at 48 weeks to TPV-based salvage regimens

The virological response (VR) to a tipranavir-ritonavir (TPV-RTV)-based regimen had been shown to be associated with a number of mutations in the protease gene, the use of enfuvirtide (T20), and the TPV phenotypic inhibitory quotient (IQ). The role of the TPV genotypic IQ (gIQ) has not yet been fully investigated. The aim of our study was to evaluate the relationship between the TPV gIQ and the VR at 48 weeks to TPV-based salvage regimens. Patients placed on regimens containing two nucleoside reverse transcriptase inhibitors plus TPV-RTV 500/200 mg twice a day with or without T20 were prospectively studied. Regular follow-up was performed over the study period. VR, considered a viral load (VL) decrease of >or=1 log unit and/or the achievement of <50 copies/ml with no VL rebound of >0.5 log unit compared to the maximal VL decrease at week 48, was assessed. Thirty-eight patients who had received multiple drugs were included. At week 48 the VL decrease was -1.48 (interquartile range [IQR], -2.88 to -0.48), 15 patients (39.5%) had VLs of <50 copies/ml, and the CD4+ cell count increase was 37 cells/mm3 (IQR, -30 to +175). Twenty subjects (52.6%) achieved VRs. The TPV gIQ and optimized background score (OBS) were independently associated with higher VL decreases. The TPV gIQ and OBS were also independent predictors of a VR at week 48. TPV gIQ and OBS cutoff values of 14,500 and 2, respectively, were associated with a higher rate of VR. The TPV gIQ was shown to be able to predict the VR at 48 weeks to TPV-containing salvage regimens better than the TPV trough concentration or TPV-associated mutations alone. A possible TPV gIQ cutoff value of 14,500 for reaching a VR at week 48 was suggested. Further studies are needed in order to evaluate the calculation of TPV gIQ as a new tool for the optimization of TPV-based salvage therapy.

Darunavir: a nonpeptidic antiretroviral protease inhibitor

BACKGROUND

Protease inhibitors were a major therapeutic breakthrough in the mid-1990s for the treatment of HIV infection, which resulted in improved life expectancy for patients who had failed previous therapies. With time and evolution of the virus, however, there is a new population of patients with treatment-resistant disease and few treatment options. Darunavir is a synthetic nonpeptidic analogue of amprenavir with enhanced activity against resistant virus that became available in 2006.

OBJECTIVES

The purpose of this review was to describe the clinical pharmacology, pharmacokinetic and pharmacodynamic properties, and clinical efficacy of darunavir. Also discussed are the published clinical experience with darunavir, its adverse events, drug interactions, pharmacoeconomics, and dosing and administration.

METHODS

A MEDLINE and EMBASE search (English-language only) was performed from January 1996 through April 2007 using the key words darunavir and TMC114. Abstracts from relevant scientific meetings were searched for the years 2000 through 2007. Additionally, the US Food and Drug Administration Web site was accessed to review the new drug application summary and data presented therein.

RESULTS

Darunavir was found to maintain antiretroviral activity against HIV with protease inhibitor mutations in 6 studies. Clinical efficacy and safety data are limited to 4 controlled and 2 uncontrolled trials. In 2 large Phase IIb clinical studies, viral suppression at 48 weeks to undetectable levels in heavily pretreated patients was achieved in 45% of patients compared with 10% of patients in the control group (P < 0.001). The addition of enfuvirtide enhanced this response rate to 58% compared with 11% of the patients who did not receive enfuvirtide (P < 0.001). Gastrointestinal symptoms, nausea, and headache were the most commonly reported events.

CONCLUSIONS

Darunavir has improved activity against resistant HIV isolates in patients with few treatment choices, particularly when enfuvirtide is added. The safety profile of darunavir is comparable to other protease inhibitors based on early data.

Health-related quality of life in homo- and bisexual men attending a sexually transmitted disease clinic in Sweden

Men who have sex with men (MSM) have an increased risk of contracting sexually transmitted diseases (STDs) and HIV. Studies of their health-related quality of life (HRQL) are uncommon, though such studies may provide additional knowledge that is of interest in counselling and care. The HRQL in MSM attending a clinic for STD- and HIV testing in Stockholm, Sweden, was investigated in 1996 and 2004, measured by means of the Swedish Health-Related Quality of Life questionnaire. The results were compared with those for men from a general Swedish population sample and with HIV-infected men. The HIV-negative MSM had significantly worse emotional wellbeing, satisfaction with family life, relation to their partner and general health perception, and better physical HRQL compared with the general Swedish population. There were no differences in the emotional and family dimensions between HIV-infected and HIV-negative MSM, but the HIV-negative group scored at a higher level in respect of their physical and general health than the HIV-infected group. No apparent differences over time were seen in the HIV-negative group. This study shows that psychosocial HRQL is lower for MSM than for a general male population sample, which calls for increased attention in the care of MSM patients.

Long-Term Efficacy and Safety of Tipranavir Boosted With Ritonavir in HIV-1-Infected Patients Failing Multiple Protease Inhibitor Regimens

BACKGROUND

BI 1182.2, an open-label, randomized, multicenter, phase 2 study, evaluated efficacy and tolerability of the protease inhibitor (PI) tipranavir (TPV; 500 mg twice daily or 1000 mg twice daily) administered with ritonavir (100 mg twice daily) in combination with 1 nucleoside reverse transcriptase inhibitor and 1 nonnucleoside reverse transcriptase inhibitor in multiple PI-experienced HIV-1-infected patients.

METHODS

Forty-one patients were evaluated in 2 arms: low-dose (19 patients) or high-dose (22 patients) ritonavir-boosted tipranavir (TPV/r). Primary endpoints were change from baseline in HIV-1 RNA concentrations at weeks 16, 24, 48, and 80 and percentage of patients with plasma HIV-1 RNA levels lower than the limit of quantitation. Safety was evaluated by adverse events (AEs), grade 3/4 abnormalities, and serious AEs.

RESULTS

Of all patients, 59% were still receiving TPV/r (14 in low-dose arm and 10 in high-dose arm) at week 80. Patients in both arms had a median >2.0-log10 reduction in plasma viral load. Intent-to-treat analysis demonstrated that a similar proportion of patients in the high-dose and low-dose groups achieved plasma HIV-1 RNA levels <50 copies/mL at week 80 (43% vs. 32%; P = 0.527). The most frequently observed AEs were diarrhea, headache, and nausea.

CONCLUSION

TPV/r combined with other active antiretroviral agents can provide a durable treatment response for highly treatment-experienced patients.

Steady-state disposition of the nonpeptidic protease inhibitor tipranavir when coadministered with ritonavir

The pharmacokinetic and metabolite profiles of the antiretroviral agent tipranavir (TPV), administered with ritonavir (RTV), in nine healthy male volunteers were characterized. Subjects received 500-mg TPV capsules with 200-mg RTV capsules twice daily for 6 days. They then received a single oral dose of 551 mg of TPV containing 90 microCi of [(14)C]TPV with 200 mg of RTV on day 7, followed by twice-daily doses of unlabeled 500-mg TPV with 200 mg of RTV for up to 20 days. Blood, urine, and feces were collected for mass balance and metabolite profiling. Metabolite profiling and identification was performed using a flow scintillation analyzer in conjunction with liquid chromatography-tandem mass spectrometry. The median recovery of radioactivity was 87.1%, with 82.3% of the total recovered radioactivity excreted in the feces and less than 5% recovered from urine. Most radioactivity was excreted within 24 to 96 h after the dose of [(14)C]TPV. Radioactivity in blood was associated primarily with plasma rather than red blood cells. Unchanged TPV accounted for 98.4 to 99.7% of plasma radioactivity. Similarly, the most common form of radioactivity excreted in feces was unchanged TPV, accounting for a mean of 79.9% of fecal radioactivity. The most abundant metabolite in feces was a hydroxyl metabolite, H-1, which accounted for 4.9% of fecal radioactivity. TPV glucuronide metabolite H-3 was the most abundant of the drug-related components in urine, corresponding to 11% of urine radioactivity. In conclusion, after the coadministration of TPV and RTV, unchanged TPV represented the primary form of circulating and excreted TPV and the primary extraction route was via the feces.

Risk factors for incident HIV infection in men having sex with men: a case-control study

BACKGROUND

HIV notifications affecting men having sex with men (MSM) in Victoria, Australia have been increasing. This study aimed to determine current risk factors for HIV infection in this population.

METHODS

Case-control study. Cases were MSM infected within the previous year (incident cases) as indicated by a previous negative test or seroconversion illness. Controls were MSM with a negative HIV test at the same clinic. From May 2001 to May 2003, cases and controls were interviewed about sexual behaviour, drug and alcohol use and mental health and sexually transmissible infections (STI) in the year before their HIV diagnosis.

RESULTS

Twenty-six cases and 52 controls were recruited. Risk factors in the year before diagnosis of incident HIV infection included: receptive unprotected anal intercourse (UAI) with ejaculation with casual partners (odds ratio [OR] and 95% confidence interval 57.2 [6.7, 489.4]); insertive UAI with ejaculation with >1 casual partners (OR 19.2 [2.2, 168.9]); having >14 casual partners at sex venues (OR 3.2 [1.1, 9.1]); and consuming >60 g alcohol at one sitting at least weekly (OR 3.6 [1.1, 11.4]). Cases were also more likely to have anal sex with >100 partners in their life and cases had more casual partners than controls in the year before the test. Cases were more likely to have consumed alcohol or amphetamines during a high-risk sexual episode in the year before the test.

CONCLUSIONS

UAI remains the most important behavioural risk for HIV in Australian MSM. Risk is increased by larger numbers of partners, partners met at sex venues and sex under the influence of alcohol.

Tipranavir: a new protease inhibitor for the treatment of antiretroviral-experienced HIV-infected patients

Tipranavir (TPV) is a novel non-peptidic protease inhibitor (PI). It binds strongly and selectively to the HIV-1 protease, is orally administered twice daily, boosted with low doses of ritonavir, and shows a favourable resistance profile. In the two registrational trials, named RESIST 1 and 2, TPV/ritonavir 500/200 mg b.i.d., along with an optimised antiretroviral backbone, provided better virologic responses than controls receiving standard of care ritonavir-boosted PI-based regimens. A total of 21 mutations at 16 protease codons have been shown to impact on TPV susceptibility and response rates. The TPV mutation score includes L10V, I13V, K20M/R/V, L33F, E35G, M36I, K43T, M46L, I47V, I54A/M/V, Q58E, H69K, T74P, V82L/T, N83D and I84V. Viruses containing eight or more of these mutations are generally resistant to the drug. TPV use is associated with an excess of grade 3/4 liver enzyme elevations compared with other ritonavir-boosted PIs, and the potential for drug-drug interactions is relevant and must be considered when prescribing TPV.

Surveillance of HIV risk and prevention behaviors of men who have sex with men--a national application of venue-based, time-space sampling

In collaboration with the Centers for Disease Control and Prevention, participating state and local health departments, universities, and community-based organizations applied venue-based, time-space sampling methods for the first wave of National HIV Behavioral Surveillance of men who have sex with men (NHBS-MSM). Conducted in 17 metropolitan areas in the United States and Puerto Rico from November 2003 through April 2005, NHBS-MSM methods included: (1) formative research to learn the venues, times, and methods to recruit MSM; (2) monthly sampling frames of eligible venues and day-time periods that met attendance, logistical, and safety criteria; and (3) recruitment of participants in accordance with randomly generated venue calendars. Participants were interviewed on HIV risk and prevention behaviors, referred to care when needed, and compensated for their time. By identifying the prevalence and trends of HIV risk and prevention behaviors, NHBS-MSM data may be used at local, state, and federal levels to help obtain, direct, and evaluate HIV prevention resources for MSM.

Unique thermodynamic response of tipranavir to human immunodeficiency virus type 1 protease drug resistance mutations

Drug resistance is a major problem affecting the clinical efficacy of antiretroviral agents, including protease inhibitors, in the treatment of infection with human immunodeficiency virus type 1 (HIV-1)/AIDS. Consequently, the elucidation of the mechanisms by which HIV-1 protease inhibitors maintain antiviral activity in the presence of mutations is critical to the development of superior inhibitors. Tipranavir, a nonpeptidic HIV-1 protease inhibitor, has been recently approved for the treatment of HIV infection. Tipranavir inhibits wild-type protease with high potency (K(i) = 19 pM) and demonstrates durable efficacy in the treatment of patients infected with HIV-1 strains containing multiple common mutations associated with resistance. The high potency of tipranavir results from a very large favorable entropy change (-TDeltaS = -14.6 kcal/mol) combined with a favorable, albeit small, enthalpy change (DeltaH = -0.7 kcal/mol, 25 degrees C). Characterization of tipranavir binding to wild-type protease, active site mutants I50V and V82F/I84V, the multidrug-resistant mutant L10I/L33I/M46I/I54V/L63I/V82A/I84V/L90M, and the tipranavir in vitro-selected mutant I13V/V32L/L33F/K45I/V82L/I84V was performed by isothermal titration calorimetry and crystallography. Thermodynamically, the good response of tipranavir arises from a unique behavior: it compensates for entropic losses by actual enthalpic gains or by sustaining minimal enthalpic losses when facing the mutants. The net result is a small loss in binding affinity. Structurally, tipranavir establishes a very strong hydrogen bond network with invariant regions of the protease, which is maintained with the mutants, including catalytic Asp25 and the backbone of Asp29, Asp30, Gly48 and Ile50. Moreover, tipranavir forms hydrogen bonds directly to Ile50, while all other inhibitors do so by being mediated by a water molecule.

Efficacy and safety of three doses of tipranavir boosted with ritonavir in treatment-experienced HIV type-1 infected patients

The efficacy, safety, and pharmacokinetics of three doses of tipranavir/ritonavir (TPV/r) in highly treatment-experienced human immunodeficiency virus (HIV)-1-infected patients with protease inhibitor (PI)-resistant isolates were evaluated. A 24-week multicenter, double-blind, randomized, dose-finding trial was conducted. All patients were three-drug class experienced and had taken at least two PI-based regimens. All had at least one primary PI mutation and had plasma HIV-RNA > 1000 copies/ml. Patients remained on their background non-PI antiretroviral medications for the first 14 days. After this 14-day period of functional TPV/r monotherapy, the background antiretroviral medications were optimized based on treatment history and the screening genotype. A total of 216 patients were randomized. All groups [TPV/r 500 mg/100 mg (n = 73), 500 mg/200 mg (n = 72), and 750 mg/200 mg (n = 71) twice daily] achieved an approximate 1 log10 reduction in the median HIV-RNA at week 2. A significant reduction was sustained through 24 weeks in the TPV/r 500 mg/200 mg and 750 mg/200 mg groups. The 500 mg/200 mg dose achieved optimal median TPV trough concentrations and lower interpatient variability. The most frequently reported adverse events (AEs) were diarrhea, nausea, vomiting, fatigue, and headache. The TPV/r 750 mg/200 mg group had the highest rate of grade 3 or 4 laboratory abnormalities and study discontinuations due to AEs. All doses of TPV/r tested in this study were associated with HIV-1 viral load reductions through 24 weeks. The 500 mg/200 mg dose achieved the best efficacy, safety, and pharmacokinetic profile in this highly treatment-experienced population and was selected for the pivotal phase 3 studies.

Making sense of syphilis: beliefs, behaviours and disclosure among gay men recently diagnosed with infectious syphilis and the implications for prevention

BACKGROUND

The resurgence of syphilis in men who have sex with men (MSM) has proved remarkably resilient in the face of innovative control and prevention interventions. Understanding the determinants of the current outbreaks has been restricted by the available data. Qualitative work is needed to understand individual and community experiences of syphilis and to help guide new prevention and control efforts.

METHODS

An exploratory study using semi-structured interviews with a convenience sample of MSM (n = 15), recently diagnosed with infectious syphilis, attending sexual health and HIV-outpatient services in Brighton, England.

RESULTS

Analysis focussed on men's beliefs about syphilis, their experience of testing and being given a syphilis diagnosis, mediators of 'risky' sexual behaviour and disclosure to social and sexual contacts. Two beliefs--'syphilis is rare' and 'syphilis is dirty'--dominated respondents' accounts. These beliefs coloured every aspect of respondents' clinical and social experience of syphilis, and impeded disclosure and partner notification. They also contributed to misconceptions about behaviours with increased syphilis transmission risk, the mechanics of disease acquisition, health-seeking behaviours and risk-reduction strategies.

CONCLUSIONS

The apparent failure of syphilis control measures so far may be due to our limited understanding of MSM's views and experience of STIs other than HIV Syphilis prevention needs to tackle MSM's widely held beliefs about sexual communication, risk behaviour and other STIs. The most useful health education interventions are likely to be those that build on MSM's significant knowledge base and address both the current syphilis crisis and wider sexual health promotion goals.

Efficacy of the Protease Inhibitors Tipranavir plus Ritonavir in Treatment-Experienced Patients: 24-Week Analysis from the RESIST-1 Trial

BACKGROUND

Improved treatment options are needed for patients infected with multidrug-resistant human immunodeficiency virus type 1 (HIV-1). The nonpeptidic protease inhibitor tipranavir has demonstrated antiviral activity against many protease inhibitor-resistant HIV-1 isolates. The Randomized Evaluation of Strategic Intervention in multi-drug reSistant patients with Tipranavir (RESIST-1) trial is an ongoing, open-label study comparing the efficacy and safety of ritonavir-boosted tipranavir (TPV/r) with an investigator-selected ritonavir-boosted comparator protease inhibitor (CPI/r) in treatment-experienced, HIV-1-infected patients.

METHODS

Six hundred twenty antiretroviral-experienced patients were treated at 125 sites in North America and Australia. Before randomization, all patients underwent genotypic resistance testing, which investigators used to select a CPI/r and an optimized background regimen. Patients were randomized to receive TPV/r or CPI/r and were stratified on the basis of preselected protease inhibitor and enfuvirtide use. Treatment response was defined as a confirmed reduction in the HIV-1 load of > or = 1 log10 less than the baseline level without treatment change at week 24.

RESULTS

Mean baseline HIV-1 loads and CD4+ cell counts were 4.74 log10 copies/mL and 164 cells/mm3, respectively. At week 24, a total of 41.5% of patients in the TPV/r arm and 22.3% in the CPI/r arm had a > or = 1-log10 reduction in the HIV-1 load (intent-to-treat population; P<.0001). Mean increases in the CD4+ cell count of 54 and 24 cells/mm3 occurred in the TPV/r and CPI/r groups, respectively. Adverse events were slightly more common in the TPV/r group and included diarrhea, nausea, and vomiting. Elevations in alanine and aspartate aminotransferase levels and in cholesterol/triglyceride levels were more frequent in the TPV/r group.

CONCLUSIONS

TPV/r demonstrated superior antiviral activity, compared with investigator-selected, ritonavir-boosted protease inhibitors, at week 24 in treatment-experienced patients with multidrug-resistant HIV-1 infection.

Ritonavir-Boosted Tipranavir Demonstrates Superior Efficacy to Ritonavir-Boosted Protease Inhibitors in Treatment-Experienced HIV-Infected Patients: 24-Week Results of the RESIST-2 Trial

BACKGROUND

Tipranavir, a novel protease inhibitor, has demonstrated antiviral activity against protease inhibitor-resistant human immunodeficiency virus type 1 (HIV-1) isolates. The Randomized Evaluation of Strategic Intervention in multi-drug reSistant patients with Tipranavir (RESIST-2) trial is an ongoing, open-label, phase III trial comparing ritonavir-boosted tipranavir (TPV/r) plus an optimized background regimen with an individually optimized, ritonavir-boosted protease inhibitor in treatment-experienced, HIV-1-infected patients.

METHODS

Patients at 171 sites in Europe and Latin America who had received > or = 2 previous protease inhibitor regimens, had triple-antiretroviral class experience, had an HIV-1 RNA level > or = 1000 copies/mL, and had genotypically demonstrated primary protease inhibitor resistance were eligible. After genotypic resistance tests were performed, a protease inhibitor and optimized background regimen were selected before randomization. Patients were randomized to receive either TPV/r or comparator protease inhibitor-ritonavir (CPI/r) and were stratified on the basis of preselected protease inhibitor and enfuvirtide use. Treatment response was defined as a confirmed HIV-1 load reduction > or = 1 log10 less than the baseline value without a treatment change at week 24.

RESULTS

A total of 863 patients were randomized and treated. At baseline, the mean HIV-1 load was 4.73 log10 copies/mL, and the mean CD4+ cell count was 218 cells/mm3. The preplanned 24-week efficacy analyses of 539 patients demonstrated treatment response rates of 41% in the TPV/r arm and 14.9% in the CPI/r arm (intent-to-treat analysis; P<.0001). The mean CD4+ cell count increased by 51 cells/mm3 in the TPV/r arm and by 18 cells/mm3 in the CPI/r arm. The most common adverse events were mild-to-moderate diarrhea, nausea, and headache. Grade 3 or greater elevations in serum transaminase, cholesterol, and triglyceride levels were more frequent in the TPV/r arm.

CONCLUSIONS

TPV/r had superior antiviral activity and increased immunologic benefits, compared with CPI/r, at week 24 among treatment-experienced patients infected with multidrug-resistant HIV-1.

Partner-Specific Sexual Behavioral Differences Between Phase 3 HIV Vaccine Efficacy Trial Participants and Controls

OBJECTIVE

To assess and compare sexual behaviors using partner-specific data between HIV-negative men who have sex with men (MSM) recruited for an HIV vaccine efficacy trial and a control group.

METHODS

HIV-negative MSM from an HIV vaccine trial (n = 525) and controls (n = 732) were recruited by similar strategies and interviewed about behaviors with the 3 most recent partners in the past 6 months, obtained by audio computer-assisted self-interview (A-CASI).

RESULTS

Vaccine trial participants were more likely than controls to report an HIV-positive partner (24.7% and 14.1%, respectively) or an HIV-positive primary partner (16.1% and 6.8%, respectively) and were less likely to report occasional or single-time partners of unknown HIV status (51.6% and 63.2%, respectively; P < 0.05 for each comparison). Vaccine trial participants more often reported receptive unprotected anal intercourse (UAI) during their last sexual encounter with an HIV-positive partner (adjusted odds ratio [OR] = 2.7, 95% confidence interval [CI]: 1.0 to 7.9). Most believed their HIV-positive partners were receiving antiretroviral treatment (ART), however, and after adjustment for perceived ART use, the association between vaccine study participation and receptive UAI with an HIV-positive partner was not significant.

CONCLUSIONS

High-risk sexual behavior was reported by many VAX004 participants and controls. Differences between vaccine trial and control participants in the highest risk per contact behavior, receptive UAI with HIV-positive partners, was partly accounted for by perceived ART use. Partner level data are useful in refining risk assessment, which is important in the evaluation of HIV vaccine and other prevention trials.

Genotypic changes in human immunodeficiency virus type 1 protease associated with reduced susceptibility and virologic response to the protease inhibitor tipranavir

Tipranavir is a novel, nonpeptidic protease inhibitor of human immunodeficiency virus type 1 (HIV-1) with activity against clinical HIV-1 isolates from treatment-experienced patients. HIV-1 genotypic and phenotypic data from phase II and III clinical trials of tipranavir with protease inhibitor-experienced patients were analyzed to determine the association of protease mutations with reduced susceptibility and virologic response to tipranavir. Specific protease mutations were identified based on stepwise multiple-regression analyses of phase II study data sets. Validation included analyses of phase III study data sets to determine if the same mutations would be selected and to assess how these mutations contribute to multiple-regression models of tipranavir-related phenotype and of virologic response. A tipranavir mutation score was developed from these analyses, which consisted of a unique string of 16 protease positions and 21 mutations (10V, 13V, 20M/R/V, 33F, 35G, 36I, 43T, 46L, 47V, 54A/M/V, 58E, 69K, 74P, 82L/T, 83D, and 84V). HIV-1 isolates displaying an increasing number of these tipranavir resistance-associated mutations had a reduced phenotypic susceptibility and virologic response to tipranavir. Regression models for predicting virologic response in phase III trials revealed that each point in the tipranavir score was associated with a 0.16-log10 copies/ml-lower virologic response to tipranavir at week 24 of treatment. A lower number of points in the tipranavir score and a greater number of active drugs in the background regimen were predictive of virologic success. These analyses demonstrate that the tipranavir mutation score is a potentially valuable tool for predicting the virologic response to tipranavir in protease inhibitor-experienced patients.

Durable efficacy of tipranavir-ritonavir in combination with an optimised background regimen of antiretroviral drugs for treatment-experienced HIV-1-infected patients at 48 weeks in the Randomized Evaluation of Strategic Intervention in multi-drug reSistant patients with Tipranavir (RESIST) studies: an analysis of combined data from two randomised open-label trials

BACKGROUND

Treatment options for HIV-1 infected individuals who have received extensive previous antiretroviral therapy are limited. We compared efficacy and safety of the novel non-peptidic protease inhibitor tipranavir co-administered with ritonavir plus an optimised background regimen with that of an investigator-selected ritonavir-boosted comparator protease inhibitor (CPI-ritonavir) in such patients.

METHODS

We did a combined analysis of 48-week data from two ongoing, randomised, open-label, multinational, phase III, RESIST studies. HIV-1-infected adults with 3 months or longer previous triple antiretroviral class experience, two or more previous protease inhibitor regimens, HIV-1 RNA 1000 copies per mL or greater, and genotypically demonstrated primary resistance to protease inhibitor, were eligible. Primary endpoints were proportion of treatment responders (with reduction in viral load of 1 log(10) copies per mL or greater below baseline without treatment change) at 48 weeks and time to treatment failure through 48 weeks (intention-to-treat analysis). The RESIST studies are registered with ClinicalTrials.gov, numbers NCT00054717 (RESIST-1) and NCT00144170 (RESIST-2).

FINDINGS

3324 patients were screened; 746 received tipranavir-ritonavir and 737 CPI-ritonavir. 486 (65.1%) patients on tipranavir-ritonavir and 192 (26.1%) on CPI-ritonavir remained on assigned treatment until week 48. At week 48, more patients achieved and maintained treatment response in the tipranavir-ritonavir group than in the CPI-ritonavir group (251 [33.6%] vs 113 [15.3%]; p<0.0001). Median time to treatment failure was significantly longer in the tipranavir-ritonavir group than in the CPI-ritonavir group (113 days vs 0 days; p<0.0001). Gastrointestinal system disorders and raised transaminase, cholesterol, and triglycerides were more frequent in the tipranavir-ritonavir group than in the CPI-ritonavir group.

INTERPRETATION

Compared with CPI-ritonavir, tipranavir-ritonavir with an optimised background regimen provides better virological and immunological responses over 48 weeks in patients who have received extensive previous antiretroviral treatment.

Long-term HIV/AIDS-related prevention behaviours among men having sex with men: Switzerland 1992-2000

The aim of this paper is to present trends in reported HIV-related behaviours among men having sex with men (MSM) in Switzerland. In 1992, 1994, 1997 and 2000 a standardized anonymous questionnaire was placed in gay newspapers and distributed in gay associations. High levels of protection (no anal sex or consistent condom use) with casual partners were found: around 90%, with a peak in 1994 and a slight decrease in 2000 to the level of 1992. With the steady partner, the level of protection was 57% in 1992, 61% in 1997 and decreased in 2000 to the same level as in 1992. The proportion of couples with both HIV statuses known increased from 49% in 1994 to 59% in 2000. In 2000, 26% of concordant HIV negative couples protected themselves compared to 83% of those exposed to an actual or potential risk (HIV status discordant or unknown). Within each category of couples, there was no change over time in the level of reported practice of anal sex and condom use. This slight decrease in prevention behaviour justifies efforts to maintain HIV/AIDS prevention targeted at gay men.

Number of risk acts by relationship status and partner serostatus: Findings from the HIM cohort of homosexually active men in Sydney, Australia

In recent years, increases in both risk behavior and in seroconversion among homosexually active men have been noted in a number of parts of the world. Data were available from 903 HIV negative homosexual men regarding number of acts of unprotected anal intercourse (UAI), separated into receptive and insertive UAI, with and without ejaculation, with steady and with casual partners. Partners were classified according to serostatus as reported by respondents. Men (N = 325) reported 13,692 UAI acts, most of which were with steady partners, of whom most were reported to be HIV-negative. With HIV-positive partners, both steady and casual, and with casual partners of unknown serostatus, receptive UAI with ejaculation was relatively rare. Insertive UAI without ejaculation was relatively common with casual partners of unknown serostatus. Patterns of UAI suggest that risk of transmission may be greater with steady partners. Men appear to modify practice according to both the nature of the relationship (steady or casual) and (assumed) serostatus of partner.