Clinical Trials Of Antiretroviral Therapy Research Articles

Weight Change Following Antiretroviral Therapy Switch in People With Viral Suppression: Pooled Data from Randomized Clinical Trials.

We sought to identify factors associated with weight gain in randomized clinical trials of antiretroviral therapy (ART) switch. We explored the effects of demographic factors, clinical characteristics, and ART on weight gain in a pooled analysis of 12 prospective clinical trials, wherein virologically suppressed people living with human immunodeficiency virus (PWH) were randomized to switch or remain on a stable baseline regimen (SBR). Both PWH randomized to switch ART (n = 4166) and those remaining on SBR (n = 3150) gained weight. Median weight gain was greater in those who switched (1.6 kg, interquartile range [IQR], -.05 to 4.0 vs 0.4 kg, [IQR], -1.8 to 2.4 at 48 weeks, P < .0001), with most weight gain occurring in the first 24 weeks after switch. Among baseline demographic and clinical characteristics, only younger age and lower baseline body mass index were associated with any or ≥10% weight gain. By week 48, 4.6% gained ≥10% weight (6.4% of switch and 2.2% of SBR), the greatest risk was with switch from efavirenz (EFV) to rilpivirine (RPV) or elvitegravir/cobicistat and switch from tenofovir disoproxil fumarate (TDF) to tenofovir alafenamide (TAF). Switch from abacavir to TAF was associated with less weight gain than switch from TDF to TAF and was not associated with increased risk for ≥10% weight gain. Moderate weight gain after ART switch was common and usually plateaued by 48 weeks. Baseline ART was a predictor of post-switch weight gain; participants who switched off of EFV and TDF had the greatest weight gain. The biological mechanisms that underlie the differential effects of switching ART agents on weight and associated clinical implications require further study.

Mother-to-Child HTLV-1 Transmission: Unmet Research Needs.

Mother-to-child transmission (MTCT) of Human T-cell lymphotropic virus type 1 (HTLV-1) causes lifelong infection. At least 5–10 million individuals worldwide are currently living with HTLV-1. Studies of regional variation are required to better understand the contribution of MTCT to the global burden of infection. Although most infected individuals remain asymptomatic ∼10% develop high morbidity, high mortality disease. Infection early in life is associated with a higher risk of disease development. Adult T-cell leukemia (ATL), which is caused by HTLV-1 and has a median survival of 8 months is linked to MTCT, indeed evidence of ATL following infection as an adult is sparse. Infective dermatitis also only occurs following neonatal infection. Whilst HTLV-1-associated myelopathy (HAM) follows sexual and iatrogenic infection approximately 30% of patients presenting with HAM/TSP acquired the infection through their mothers. HAM/TSP is a disabling neurodegenerative disease that greatly impact patient’s quality of life. To date there is no cure for HTLV-1 infection other than bone marrow transplantation for ATL nor any measure to prevent HTLV-1 associated diseases in an infected individual. In this context, prevention of MTCT is expected to contribute disproportionately to reducing both the incidence of HTLV-1 and the burden of HTLV-1 associated diseases. In order to successfully avoid HTLV-1 MTCT, it is important to understand all the variables involved in this route of infection. Questions remain regarding frequency and risk factors for in utero peri-partum transmission whilst little is known about the efficacy of pre-labor cesarean section to reduce these infections. Understanding the contribution of peripartum infection to the burden of disease will be important to gauge the risk-benefit of interventions in this area. Few studies have examined the impact of HTLV-1 infection on fertility or pregnancy outcomes nor the susceptibility of the mother to infection during pregnancy and lactation. Whilst breast-feeding is strongly associated with transmission and avoidance of breast-feeding a proven intervention little is known about the mechanism of transmission from the breast milk to the infant and there have been no clinical trials of antiretroviral therapy (ARV) to prevent this route of transmission.

Meta-Analysis of Gender Differences in Efficacy Outcomes for HIV-Positive Subjects in Randomized Controlled Clinical Trials of Antiretroviral Therapy (2000–2008)

Women are often underrepresented in randomized clinical trials (RCT) of HIV-1 drugs. As a result, determining whether women have different virologic outcomes compared to men is not always possible because the gender-related analyses usually lack statistical power. To address this important public health concern, the Food and Drug Administration's (FDA) Division of Antiviral Products (DAVP) created a database including 20,328 HIV-positive subjects from 40 RCTs in 18 New Drug Applications (NDAs) submitted to the FDA between 2000 and 2008. These RCTs were conducted for at least 48 weeks in duration and were used to support approval of new molecular entity, new formulation, or major label change. To delineate potential gender differences in antiretroviral treatment (ART), we evaluated the percentage of subjects with HIV RNA less than 50 copies per milliliter at 48 weeks. Analyses of the database represent the most systematic review of gender-related ART efficacy data to date. Overall, the meta-analyses did not demonstrate statistically or clinically significant gender differences in virologic outcome at week 48. However, the corresponding subgroup analyses appear to show several statistically significant gender differences favoring males.

Impact of lamivudine on HIV and hepatitis B virus-related outcomes in HIV/hepatitis B virus individuals in a randomized clinical trial of antiretroviral therapy in southern Africa

To examine HIV and hepatitis B virus (HBV)-related outcomes in HIV/HBV-coinfected participants in the PHIDISA II study by use of HBV-active vs. non-HBV-active antiretroviral therapy (ART). PHIDISA II was a randomized study of ART therapy in HIV-infected adults employing zidovudine along with didanosine, or lamivudine along with stavudine in a factorial 2x2 design. HIV/HBV-coinfected participants by randomization received HBV-active or non-HBV-active ART. The following outcomes of interest were examined: immunological recovery and HIV RNA suppression; hepatic flare; HBV DNA suppression; and mortality. HIV/HBV coinfection was present in 106 of 1771 (6%) of participants. Participants with HIV/HBV coinfection were more likely to be men, and have higher baseline alanine aminotransferase, lower albumin, and lower platelets than those with HIV monoinfection. Median CD4 cell gain and HIV RNA suppression was similar across all groups. Hepatic flare was observed in 9.4% of coinfected and 0.02% monoinfected participants. HBV DNA suppression (<55 IU/ml) at week 48 was observed in only 33% of those on lamivudine vs. 13% in those on no HBV-active drugs (P = 0.13). Mortality over follow-up was significantly greater in coinfected (17%) than monoinfected (11%) participants (P = 0.04). In summary, the use of lamivudine-containing ART in HIV/HBV participants in PHIDISA II resulted in little additional benefit over that of ART itself and failed to impact on the greater mortality in this group. These data provide strong support for recent guidelines advocating the use of tenofovir in all HIV-HBV-coinfected individuals initiating ART.

Lipid Changes Differ Within HIV Drug Classes

Reports from recent clinical trials of antiretroviral therapy always include information about the effects of treatment on lipid levels. However, these

Dual Nucleoside Reverse Transcriptase Inhibitor Therapy in the Combination Antiretroviral Therapy Era and Predictors of Discontinuation or Switch to Combination Antiretroviral Therapy

Contrary to current HIV/AIDS management guidelines, and despite the arrival of potent combination antiretroviral therapy (cART) many years ago, some patients are still treated with dual nucleoside reverse transcriptase inhibitor (NRTI) regimens. We selected 5222 patients who received dual NRTI therapy for at least 6 months during 1998 to 2002, representing 9.9% of the 52,981 ARV-treated patients recorded in the French Hospital Database on HIV. Factors associated with switching to cART or with ARV discontinuation were identified by using Cox models. The 3-year probabilities of switching to cART and of antiretroviral (ARV) drug discontinuation were 55.2% (95% confidence interval [CI]: 53.8 to 56.7) and 10.9% (95% CI: 10.1 to 11.8), respectively, whereas 1591 patients (30.5%) kept the dual NRTI therapy during all the study period. Place of birth and region of care did not influence the choice of treatment strategy. After adjustment, the likelihood of switching to cART was lower among women, intravenous drug users, and patients with an undetectable plasma viral load (pVL) on at least 1 occasion during follow-up; in contrast, it was higher among patients with AIDS and those with a low CD4 cell count at enrollment or at the last follow-up visit. The likelihood of ARV discontinuation was higher among women and intravenous drug users and lower among patients with a low CD4 cell count at inclusion or at the last follow-up visit and among patients with an undetectable pVL on at least 1 occasion during follow-up. The likelihood of switching to cART or discontinuing ARV drugs was higher among patients receiving zidovudine/zalcitabine or didanosine/stavudine than among those receiving zidovudine/lamivudine. In France, until recent years, some patients (mainly women and intravenous drug users) were still receiving dual NRTI therapy despite free access to care and to highly effective ARV regimens. Dual NRTI therapy is gradually being replaced by cART, although some patients with satisfactory immunovirologic status are discontinuing all ARV drugs.

Maximum Likelihood Estimation in Dynamical Models of HIV

The study of dynamical models of HIV infection, based on a system of nonlinear ordinary differential equations (ODE), has considerably improved the knowledge of its pathogenesis. While the first models used simplified ODE systems and analyzed each patient separately, recent works dealt with inference in non-simplified models borrowing strength from the whole sample. The complexity of these models leads to great difficulties for inference and only the Bayesian approach has been attempted by now. We propose a full likelihood inference, adapting a Newton-like algorithm for these particular models. We consider a relatively complex ODE model for HIV infection and a model for the observations including the issue of detection limits. We apply this approach to the analysis of a clinical trial of antiretroviral therapy (ALBI ANRS 070) and we show that the whole algorithm works well in a simulation study.

Black Women Underrepresented in HIV Clinical Studies

Previous studies have shown that women of color are often underrepresented in clinical trials of antiretroviral therapy. Enrollment of nonrepresentative patient populations, as a result of either patient choice or provider selection, can bias study results and generate conclusions with limited applicability. To shed light on this issue, investigators evaluated rates and reasons for nonenrollment in a large prospective cohort study on interventions to prevent mother-to-child HIV transmission and to protect maternal health. Of …

Issues Regarding Use of Hormonal Contraceptives in Clinical Trials of Antiretroviral Therapy

Objective Over 30% of HIV-infected adults and adolescents in the United States are female, yet women make up less than 20% of participants in most antiretroviral clinical trials. We sought to understand how policies regarding fertility regulation might have influenced women's participation in Adult AIDS Clinical Trials Group (AACTG) antiretroviral trials. Methods We reviewed AACTG and the National Institute of Allergy and Infectious Diseases Division of AIDS (DAIDS) policies relating to the eligibility of women of reproductive potential to participate in antiretroviral clinical trials from 1996 to the present. We focused specifically on policies related to the documentation of women's reproductive potential, contraceptive requirements stratified by the FDA Use-in-Pregnancy categories, the management of incident pregnancies for female study subjects, and the impact of previous limited antiretroviral use in pregnancy and eligibility for antiretroviral-naive clinical trials. Results Before 1998, most AACTG protocols specified that ‘adequate birth control’ should be used during clinical trials and for 3 months afterwards, but there was no standard definition of adequate birth control. Most protocols implied that it was the woman's responsibility to prevent pregnancy. In 1998, a focus group on pregnancy issues and antiretroviral agents recommended that adequate birth control should be practised by both heterosexually active women and men on study. Adequate birth control was defined as either abstinence, hormonal plus barrier methods, or two barrier methods. In 2000, women of reproductive potential were explicitly defined as all adult and adolescent women except those who have undergone surgical sterilization, hysterectomy, bilateral oophorectomy or menopause, or whose male partners have documented azoospermia from a vasectomy or other condition. Source documentation of sterilization, menopause or azoospermia was required to confirm a lack of reproductive potential for study subjects. Women of reproductive potential were required to use at least one non-hormonal contraceptive method for trials involving FDA category A, B and most category C drugs, and were required to use two non-hormonal contraceptive methods for some category C drugs (efavirenz) and all category D and X drugs. Hormonal contraceptive methods were thought to be possibly ineffective when prescribed with some antiretroviral agents, and so could not fulfill the contraceptive requirement. IUD were discouraged because of the potential increased risk of pelvic inflammatory disease. In 2002, the source documentation requirement for women not of reproductive potential was relaxed for trials of category A, B and C drugs with the exception of efavirenz; however, the contraceptive requirements were not changed. Most antiretroviral trials require that female study subjects who become pregnant discontinue study medications unless there are adequate safety data in pregnancy. Most clinical trials for antiretroviral-naive study subjects exclude women with limited previous exposure to zidovudine or nevirapine during a pregnancy. Conclusion The vast majority of HIV-infected women in the United States are of child-bearing age, and so fertility regulation policies may have a substantial impact on women's eligibility for and participation in antiretroviral clinical trials. The burden of pregnancy prevention disproportionately affects women, including those who are not heterosexually active but are still thought to be ‘of reproductive potential’. We need better and more complete data regarding the safety, pharmacokinetics and efficacy of newer antiretroviral agents in pregnancy and in conjunction with hormonal contraceptives. In addition, antiretroviral-naive clinical trials should consider whether the exclusion of women with previous limited antiretroviral exposure in pregnancy is truly justified.

Rapid Communications

Objective: To determine the ability of intermediate plasma viral load (pVL) measurements to predict virologic outcome at 52 weeks of follow-up in clinical trials of antiretroviral therapy. Methods: Individual patient data from three clinical trials (INCAS, AVANTI-2 and AVANTI-3) were combined into a single database. Virologic success was defined to be plasma viral load (pVL) <500 copies/ml at week 52. The sensitivity and specificity of intermediate pVL measurements below the limit of detection, 100, 500, 1000, and 5000 copies/ml to predict virologic success were calculated. Results: The sensitivity, specificity, and positive and negative predictive values of a pVL measurement <1000 copies/ml at week 16 to predict virologic outcome at week 52 were 74%, 74%, 48%, and 90%, respectively, for patients on double therapy. For patients on triple therapy, the sensitivity, specificity, and positive and negative predictive values of a pVL measurement <50 copies/ml at week 16 to predict virologic outcome were 68%, 68%, 80%, and 47%, respectively. Conclusions: For patients receiving double therapy, a poor virologic result at an intermediate week of follow-up is a strong indicator of virologic failure at 52 weeks whereas intermediate virologic success is no guarantee of success at 1 year. For patients on triple therapy, disappointing intermediate results do not preclude virologic success at 1 year and intermediate successes are more likely to be sustained.

Predicting HIV RNA Virologic Outcome at 52-Weeks Follow-Up in Antiretroviral Clinical Trials

Objective: To determine the ability of intermediate plasma viral load (pVL) measurements to predict virologic outcome at 52 weeks of follow-up in clinical trials of antiretroviral therapy. Methods: Individual patient data from three clinical trials (INCAS, AVANTI-2 and AVANTI-3) were combined into a single database. Virologic success was defined to be plasma viral load (pVL) <500 copies/ml at week 52. The sensitivity and specificity of intermediate pVL measurements below the limit of detection, 100, 500, 1000, and 5000 copies/ml to predict virologic success were calculated. Results: The sensitivity, specificity, and positive and negative predictive values of a pVL measurement <1000 copies/ml at week 16 to predict virologic outcome at week 52 were 74%, 74%, 48%, and 90%, respectively, for patients on double therapy. For patients on triple therapy, the sensitivity, specificity, and positive and negative predictive values of a pVL measurement <50 copies/ml at week 16 to predict virologic outcome were 68%, 68%, 80%, and 47%, respectively. Conclusions: For patients receiving double therapy, a poor virologic result at an intermediate week of follow-up is a strong indicator of virologic failure at 52 weeks whereas intermediate virologic success is no guarantee of success at I year. For patients on triple therapy, disappointing intermediate results do not preclude virologic success at I year and intermediate successes are more likely to be sustained.

Guide to major clinical trials of antiretroviral therapy in human immunodeficiency virus-infected patients: protease inhibitors, non-nucleoside reverse transcriptase inhibitors, and nucleotide reverse transcriptase inhibitors.

In this AIDS Commentary, Drs. Tavel, Miller, and Masur of the National Institutes of Health present this compilation of clinical trials of antiretroviral therapy in HIV-infected patients, which complements two similar reviews published as AIDS Commentaries in Clinical Infectious Diseases (1995;20:1145–51 and 1996;23:15–27). Whereas the previous compilations focused on trials of nucleoside analogues, this review is based on published articles and abstracts of clinical trials of protease inhibitors, non-nucleoside reverse transcriptase inhibitors, and nucleotide reverse transcriptase inhibitors in HIV-infected patients. The intent is to present a thorough, but not necessarily exhaustive, review of studies that have shaped our principles of antiretroviral therapy. Preference is given to clinical endpoint trials, proof-of-concept trials that have influenced the standard of care for HIV treatment, double-blind, randomized trials, and large trials with long-term patient followup. Smaller trials that address important questions are also included.

Guide to major clinical trials of antiretroviral therapy administered to patients infected with human immunodeficiency virus.

Guide to major clinical trials of antiretroviral therapy administered to patients infected with human immunodeficiency virus.

Considerations in choice of a clinical endpoint for AIDS clinical trials. Terry Beirn Community Programs for Clinical Research on AIDS (CPCRA).

In most clinical trials of antiretroviral therapy for patients infected with HIV, the major outcome variable has been the combined clinical endpoint of any new or recurrent AIDS defining event. We review features of combined endpoints and use data from the Terry Beirn Community Programs for Clinical Research on AIDS (CPCRA) to evaluate this outcome measure in terms of relevance, diagnostic certainty and sensitivity. We conclude that this endpoint is not relevant because: (i) the 19 different events constituting the combined endpoint are equally weighted in analyses even though they vary considerably in terms of risk of death; and (ii) events after the first are ignored, thus the event profile of patients is not taken into account in making treatment comparisons. We also conclude that power may be low with use of this endpoint if treatments under study do not have an immediate impact on disease progression, if some events which occur soon after randomization represent a disease process that has already begun to incubate, or if treatment differences for the various events constituting the combined endpoint are differentially effected by treatment. Since the ease and certainty of diagnosis of each of the 19 events also vary, we recommend that survival be the primary endpoint of antiretroviral trials, and that all opportunistic events experienced by patients, not just the first, be collected and summarized. Trial reports should include comparisons of incidence of each event by treatment group so that readers can rank events as they please. A single summary measure which considers severity and the entire event profile, as described here, would also be useful for assessing the impact of treatments on quality of life. Further research on approaches for weighting and combining multiple outcome measures is needed.