Virologic efficacy of boosted double versus boosted single protease inhibitor therapy

Nonrandomized studies using causal-modeling may give different answers than RCTs: a meta-epidemiological study

OBJECTIVES

To evaluate how estimated treatment effects agree between nonrandomized studies using causal modeling with marginal structural models (MSM-studies) and randomized trials (RCTs).

STUDY DESIGN

Meta-epidemiological study.

SETTING

MSM-studies providing effect estimates on any healthcare outcome of any treatment were eligible. We systematically sought RCTs on the same clinical question and compared the direction of treatment effects, effect sizes, and confidence intervals.

RESULTS

The main analysis included 19 MSM-studies (1,039,570 patients) and 141 RCTs (120,669 patients). MSM-studies indicated effect estimates in the opposite direction from RCTs for eight clinical questions (42%), and their 95% CI (confidence interval) did not include the RCT estimate in nine clinical questions (47%). The effect estimates deviated 1.58-fold between the study designs (median absolute deviation OR [odds ratio] 1.58; IQR [interquartile range] 1.37 to 2.16). Overall, we found no systematic disagreement regarding benefit or harm but confidence intervals were wide (summary ratio of odds ratios [sROR] 1.04; 95% CI 0.88 to 1.23). The subset of MSM-studies focusing on healthcare decision-making tended to overestimate experimental treatment benefits (sROR 1.44; 95% CI 0.99 to 2.09).

CONCLUSION

Nonrandomized studies using causal modeling with MSM may give different answers than RCTs. Caution is still required when nonrandomized "real world" evidence is used for healthcare decisions.

Adult antiretroviral therapy guidelines 2017

These guidelines are intended as an update to those published in the Southern African Journal of HIV Medicine in 2014 and the update on when to initiate antiretroviral therapy in 2015. Since the release of the previous guidelines, the scale-up of antiretroviral therapy (ART) in southern Africa has continued. New antiretroviral drugs have become available with improved efficacy, safety and robustness. The guidelines are intended for countries in the southern African region, which vary between lower and middle income.

Comparative Effectiveness of First Antiretroviral Regimens in Clinical Practice Using a Causal Approach

The objective of this study was to estimate the cumulative incidences of failure by months 12 (M12) and 24 (M24) for the most prescribed first-line anti-retroviral regimens (ART). It is retrospective analysis of a prospectively collected database. All patients who initiated their first ART with the most prescribed regimens between 1st January 2004 and 30th June 2013 in 12 large HIV reference centers in France were included. The outcome was treatment failure--defined by any treatment modification for virological or tolerability reasons--and comparisons between regimens were carried out at M12 and M24. Adjusted and weighted methods via the propensity score (PS) were used to compare the effectiveness of the first antiretroviral regimens. Potential confounders of the treatment-outcome association were used to estimate PS with multinomial logistic regression. Overall, 3128 and 2690 patients were included in the M12 and M24 analyses, respectively. Patients received 5 different regimens (ABC/3TC with ATV/r or DRV/r, TDF/FTC with ATV/r, DRV/r, or EFV). Failure was reported in 25% and 42% at M12 and M24, respectively. Patients who received TDF/FTC/EFV had a significantly higher proportion of failure at M12 by comparison with TDF/FTC with DRV/r (reference), but not at M24. Patients in the 3 other groups had a trend toward a higher proportion of failure at M12 although not statistically significant. No difference was found at M24. Using data from a large prospective cohort, we found that boosted atazanavir and darunavir had comparable effectiveness, whatever the associated NRTIs, whereas efavirenz-based regimens were relatively less performing on the short term.

Comparative risk of failure of ABC/3TC or TDF/FTC based first-line regimens in patients with a high viral load

OBJECTIVES

To compare the efficacy, in current clinical practice, of first regimens containing abacavir with lamivudine (ABC/3TC) or tenofovir with emtricitabine (TDF/FTC) in patients with baseline viral load ≥100,000 HIV-1 RNA copies/mL.

METHODS

Using a prospective cohort, we selected all patients starting a first HIV regimen based either on ABC/3TC or on TDF/FTC. The propensity score (PS) method was used to limit the indication bias due to the observational nature of the data. Adjusting and weighting methods via PS were used to compare the effectiveness of a first regimen containing ABC/3TC or TDF/FTC. The primary outcome was treatment failure by month 12 (M12).

RESULTS

Overall, 2781 patients started an antiretroviral (ARV) regimen with ABC/3TC or TDF/FTC each in combination with efavirenz, boosted atazanavir or boosted darunavir. Among the 2472 uncensored patients before M12, 962 (39%) had a baseline viral load ≥100,000 copies/mL of whom 294 were in treatment failure at or before M12. Our analyses showed no difference between ABC/3TC and TDF/FTC in the risk of treatment failure at M12 in patients starting an ARV regimen with a high viral load (≥100,000 copies/mL).

CONCLUSIONS

Using a large prospectively collected cohort of patients seeking care in France, we found no evidence that ABC/3TC based regimens led to more failures than TDF/FTC based ones in patients with high baseline viral loads.

Outcomes of patients on dual-boosted PI regimens: experience of the Swiss HIV cohort study

Dual-boosted protease inhibitors (DBPI) are an option for salvage therapy for HIV-1 resistant patients. Patients receiving a DBPI in the Swiss HIV Cohort Study between January1996 and March 2007 were studied. Outcomes of interest were viral suppression at 24 weeks. 295 patients (72.5%) were on DBPI for over 6 months. The median duration was 2.2 years. Of 287 patients who had HIV-RNA >400 copies/ml at the start of the regimen, 184 (64.1%) were ever suppressed while on DBPI and 156 (54.4%) were suppressed within 24 weeks. The median time to suppression was 101 days (95% confidence interval 90-125 days). The median number of past regimens was 6 (IQR, 3-8). The main reasons for discontinuing the regimen were patient's wish (48.3%), treatment failure (22.5%), and toxicity (15.8%). Acquisition of HIV through intravenous drug use and the use of lopinavir in combination with saquinavir or atazanavir were associated with an increased likelihood of suppression within 6 months. Patients on DBPI are heavily treatment experienced. Viral suppression within 6 months was achieved in more than half of the patients. There may be a place for DBPI regimens in settings where more expensive alternates are not available.

Role of tipranavir in treatment of patients with multidrug-resistant HIV

The worldwide emergence of multidrug-resistant human immunodeficiency virus (HIV)-1 strains has the driven the development of new antiretroviral (ARV) agents. Over the past 5 years, HIV-entry and integrase inhibitor ARVs, as well as improved non-nucleoside reverse transcriptase inhibitors (NRTIs) and protease inhibitors (PIs), have become available for treatment. It is important to assess how these new ARVs might be most judiciously used, paying close attention to viral susceptibility patterns, pharmacodynamic parameters, and the likelihood that patients will adhere to their therapy. Herein we review published material in Medline, EMBASE, and ISI for each antiretroviral agent/classes currently approved and summarize the available data on their efficacy, safety, and pharmacologic parameters. We focus on the role of tipranavir, a recently approved nonpeptidic PI, for treating HIV-infected children, adolescents, and adults with a history of multidrug-resistant HIV.

Effectiveness of boosted protease inhibitor-based regimens in HIV type 1-infected patients who experienced virological failure with NNRTI-based antiretroviral therapy in a resource-limited setting

A number of patients have experienced treatment failure while receiving non-nucleoside reverse transcriptase inhibitor (NNRTI)-based antiretroviral therapy (ART), particularly in resource-limited countries. The need remains for clinical data on protease inhibitor (PI)-based regimens in these patients. A retrospective cohort study was conducted among HIV-1-infected patients who had failed NNRTI-based regimens, were naive to protease inhibitors (PIs), and subsequently initiated a salvage PI-based regimen between January 2004 and December 2006. The study period ended on 30 December 2007. One hundred and forty patients received a single-boosted PI +/- optimized background regimen (OBR) and 64 received double-boosted PIs. The median (IQR) duration of follow-up was 19 (13-29) months. The overall virological failure rate at 24 months was 15.2%. No statistically significant difference was detected between the two regimen groups (single-boosted PI +/- OBR 16.4% vs. double-boosted PIs 12.5%, log rank p = 0.818). At the end of the study, the median (IQR) change in CD4 cell counts for patients in the double-boosted PI group was higher than for patients in the single-boosted PI +/- OBR group [149 (53-322) vs. 105 (23-199), respectively, p = 0.012]. Patients receiving double-boosted PI regimens displayed a higher frequency of hypertriglyceridemia than those patients who received a single boosted PI +/- OBR (31% vs. 11%, respectively, p = 0.001). Boosted PI-based regimens showed acceptable virological outcomes among patients who had failed NNRTI-based ART. In the subgroup analysis, patients who received double-boosted PIs demonstrated a superior immunological response but not better virological outcomes compared to the single-boosted PI +/- OBR group.

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.

Tipranavir: a new protease inhibitor for the pediatric population

Highly active antiretroviral therapy can provide sustained viral suppression and a beneficial immunological response in both antiretroviral-naive and -experienced pediatric patients infected with HIV. While there have been many antiretroviral studies in adults infected with HIV, considerably less information is available in similar HIV-infected pediatric or adolescent patients. Tipranavir, a new-generation protease inhibitor approved for use in adults with resistant HIV strains, has recently been studied in HIV-infected children and adolescents. In this article, we summarize available pharmacokinetic, safety, tolerability and efficacy data obtained from children and adolescents treated with a pediatric tipranavir formulation.

Safety and efficacy of a double-boosted protease inhibitor combination, saquinavir and lopinavir/ ritonavir, in pretreated children at 96 weeks

Background

This study aimed to assess the long-term efficacy, safety and use of therapeutic drug monitoring (TDM) of a double-boosted protease inhibitor (PI) combination, saquinavir (SQV) and lopinavir/ritonavir (LPV/r), in Thai HIV type-1 (HIV-1)-infected children who had failed on reverse transcriptase inhibitors.

Methods

In total, 50 children from two sites in Thailand were treated with standard dosing of SQV and LPV/r. CD4+ T-cell count and percentage, viral load (VL; HIV-1 RNA), minimum plasma drug concentrations (Cmin) and drug safety laboratory evaluations were monitored. Virological failure was defined as having two consecutive VL measures >400 copies/ml after week 12. An intention-to-treat analysis was performed.

Results

Baseline data were a median age of 9.3 years (interquartile range [IQR] 7.1–11.2), VL 4.8 log10 copies/ ml (IQR 4.5–5.1) and CD4+ T-cell percentage 7% (IQR 3.0– 9.5). CDC classifications were N=4%, A=14%, B=68% and C=14% of participants. Median CD4+ T-cell percentage and CD4+ T-cell count increase were 14% (IQR 7–19) and 558 cells/mm3 (IQR 308–782), respectively (both P<0.001). Overall, 37 (74%) children achieved VL<50 copies/ml with significant differences between sites (90% versus 63%). Over 96 weeks, 10 patients had virological failure. Total cholesterol and high-density lipoprotein increased significantly over time, whereas the triglycerides and low-density lipoprotein did not. Approximately 50% of participants reported no change in body shape, and 33%, 43% and 39% reported fatter arms, face and abdomen, respectively. LPV and SQV Cmin were high and stable over time.

Conclusions

Double-boosted SQV+LPV/r was an effective and safe alternative for a second-line regimen in children. Hypercholesterolaemia needs close follow-up. On the basis of the TDM results, PI dose reduction in this population should be considered.