AIDS vaccine efficacy trials: expand capacity and prioritize. 'Throughout Africa, Asia and Latin America state-of-the-art clinics and laboratories...exist where, 4 years ago, there were none'

HIV-vaccines: lessons learned and the way forward

A safe and efficacious preventive HIV vaccine, as part of a comprehensive prevention program, remains among the highest public health priorities. It would be the best tool that could reduce the spread of HIV significantly in the long run. Current AIDS vaccine candidates are unable to induce neutralizing antibodies against primary HIV isolates or only to a very limited and narrow extent, representing a major obstacle in the development of an efficacious HIV vaccine. Clinical efforts have mainly focused on T-cell vaccines such as DNA and various recombinant vectors alone or in prime-boost regimens. The Merck Ad5 vaccine not only failed to show efficacy but also was associated with increased risk of HIV acquisition in vaccinees in a Phase IIb trial. While gp120 alone was not efficacious, the ALVAC prime and gp120 boost regimen showed 31% efficacy in a Phase III trial in Thailand. These contrasting results illustrate the limitations of available laboratory assays to assess the vaccine-induced immune responses and the lack of understanding of immune correlates of protection. Efforts should therefore focus on developing vaccine candidates inducing broadly neutralizing antibodies. Similarly, new vector strategies such as replicating vectors should be explored to induce strong and broad T-cell responses in the systemic and mucosal compartments. Innovation in immune assay development and testing algorithms is critically needed. The standardization of more relevant and predictive non-human primate models for immunogenicity and efficacy studies will contribute to better and faster vaccine assessment. HIV vaccine development requires innovative ideas and a sustained long-term commitment of the scientific community, civil society, politicians, and donors and participants for clinical research.

Health research capacity development in low and middle income countries: reality or rhetoric? A systematic meta-narrative review of the qualitative literature

OBJECTIVES

Locally led health research in low and middle income countries (LMICs) is critical for overcoming global health challenges. Yet, despite over 25 years of international efforts, health research capacity in LMICs remains insufficient and development attempts continue to be fragmented. The aim of this systematic review is to identify and critically examine the main approaches and trends in health research capacity development and consolidate key thinking to identify a more coherent approach.

METHODS

This review includes academic and grey literature published between January 2000 and July 2013. Using a predetermined search strategy, we systematically searched PubMed, hand-searched Google Scholar and checked reference lists. This process yielded 1668 papers. 240 papers were selected based on a priori criteria. A modified version of meta-narrative synthesis was used to analyse the papers.

RESULTS

3 key narratives were identified: the effect of power relations on capacity development; demand for stronger links between research, policy and practice and the importance of a systems approach. Capacity development was delivered through 4 main modalities: vertical research projects, centres of excellence, North-South partnerships and networks; all were controversial, and each had their strengths and weaknesses. A plurality of development strategies was employed to address specific barriers to health research. However, lack of empirical research and monitoring and evaluation meant that their effectiveness was unclear and learning was weak.

CONCLUSIONS

There has been steady progress in LMIC health research capacity, but major barriers to research persist and more empirical evidence on development strategies is required. Despite an evolution in development thinking, international actors continue to use outdated development models that are recognised as ineffective. To realise newer development thinking, research capacity outcomes need to be equally valued as research outputs. While some development actors are now adopting this dedicated capacity development approach, they are in the minority.

Evaluation of locally established reference intervals for hematology and biochemistry parameters in Western Kenya

Background

Important differences have been demonstrated in laboratory parameters from healthy persons in different geographical regions and populations, mostly driven by a combination of genetic, demographic, nutritional, and environmental factors. Despite this, European and North American derived laboratory reference intervals are used in African countries for patient management, clinical trial eligibility, and toxicity determination; which can result in misclassification of healthy persons as having laboratory abnormalities.

Methods

An observational prospective cohort study known as the Kisumu Incidence Cohort Study (KICoS) was conducted to estimate the incidence of HIV seroconversion and identify determinants of successful recruitment and retention in preparation for an HIV vaccine/prevention trial among young adults and adolescents in western Kenya. Laboratory values generated from the KICoS were compared to published region-specific reference intervals and the 2004 NIH DAIDS toxicity tables used for the trial.

Results

About 1106 participants were screened for the KICoS between January 2007 and June 2010. Nine hundred and fifty-three participants aged 16 to 34 years, HIV-seronegative, clinically healthy, and non-pregnant were selected for this analysis. Median and 95% reference intervals were calculated for hematological and biochemistry parameters. When compared with both published region-specific reference values and the 2004 NIH DAIDS toxicity table, it was shown that the use of locally established reference intervals would have resulted in fewer participants classified as having abnormal hematological or biochemistry values compared to US derived reference intervals from DAIDS (10% classified as abnormal by local parameters vs. >40% by US DAIDS). Blood urea nitrogen was most often out of range if US based intervals were used: <10% abnormal by local intervals compared to >83% by US based reference intervals.

Conclusion

Differences in reference intervals for hematological and biochemical parameters between western and African populations highlight importance of developing local reference intervals for clinical care and trials in Africa.

Laboratory expansion to large-scale international HIV preventive vaccine trials

PURPOSE OF REVIEW

The purpose of this article is to describe the requirements for clinical laboratories supporting large-scale multinational trials of prophylactic AIDS vaccine trials and review the progress made.

RECENT FINDINGS

There is an increasing need for laboratories in Africa, Asia and the Caribbean to support internationally initiated and funded clinical trials of preventive HIV vaccine candidates. A number of qualified laboratories are currently supporting AIDS vaccine trials in these regions, although there remains a need to develop capacity further. The standardization of all tests is key in order that data can be pooled and compared across multiple sites and products. Significant progress has been made towards this aim. The recent development of quality programmes including good clinical laboratory practices are key to ensuring data are reliable and meet the requirements of regulatory bodies. In addition, HIV diagnostic tests are being developed to distinguish true HIV infection from vaccine-induced antibodies.

SUMMARY

Significant advances have been made to develop laboratories capable of supporting multinational AIDS vaccine trials.

Immunohaematological reference values for HIV-negative healthy adults in Botswana

Background

Clinical laboratories in Botswana have relied entirely on the reference intervals for normal immunohaematological values provided by manufacturers’ kits and textbooks.

Objectives

The aim of this study was to determine the means, medians, 2.5th and 97.5th percentile reference intervals, for normal immunohaematological values in healthy adults in Botswana.

Method

A total of 261 healthy participants comprising 126 men (48%) and 135 (52%) women were enrolled in the southern part of Botswana, and immunological and haematological laboratory parameters were measured.

Results

The mean age was 28.8 (95% Confidence Interval [CI] 27.7–29.8) years, with a median of 27 years and a range 18–66 years. The mean haemoglobin level was significantly lower for women (12.4 g/dL; 95% CI 12.1% – 12.7%) than men (15.1 g/dL; 95% CI 14.9% – 15.3%). The women’s haemoglobin reference values (9.0 g/dL – 15.0 g/dL) levels were lower than observed in predominantly White populations (12.0 g/dL – 16.0 g/dL), but comparable with regional consensus reference intervals (9.5 g/dL – 15.8 g/dL) recently defined for East and Southern Africa.

Conclusion

The established values provide an important tool for patient management and could influence decisions on inclusion of participants and adverse events in clinical trials conducted locally.

HIV vaccines: lessons learned and the way forward

PURPOSE OF REVIEW

An effective HIV vaccine is a global health priority. We describe lessons learned from four HIV vaccine trials that failed to demonstrate efficacy and one that showed modest protection as a pathway forward.

RECENT FINDINGS

The Merck Ad5 phase IIb T-cell vaccine failed to show efficacy and might have increased the risk of HIV acquisition in men who have sex with men. Although VaxGen gp120 alone was not efficacious in groups at high risk for HIV-1 infection, the RV144 ALVAC prime and gp120 boost regimen showed 31% efficacy in low-incidence heterosexuals. All trials demonstrated the limitations of available laboratory and animal models to assess relevant vaccine-induced immune responses and predict clinical trial outcome. Analysis of innate and adaptive responses induced in RV144 will guide future trial design.

SUMMARY

Future HIV vaccine trials should define the RV144 immune responses relevant to protection, improve durability and level of protection, and assess efficacy in diverse risk groups. New strategies examining heterologous vector prime-boost, universal inserts, replicating vectors, and novel protein or adjuvant immunogens should be explored to induce T-cell and antibody responses. HIV vaccine development requires innovative ideas and a sustained long-term commitment of scientists, governments, and the community.

HIV vaccines: current status worldwide and in Africa

Since HIV-1 was identified, development of a preventive vaccine has been a major goal. Significant progress toward that goal has been made by 2010. In macaques, a vigorous T effector cell response has protected some animals from disease caused by simian immunodeficiency virus (SIV). Broadly, neutralizing human anti-HIV antibodies have been isolated and their structures, and targets are rapidly being elucidated. For the first time an AIDS vaccine has shown modest protective efficacy in a human clinical trial. To reach the final goal, there is a need for a coordinated global effort, including a range of approaches including novel high-throughput screening techniques, X-ray crystallography, and monoclonal antibody isolation, analysis of T cell responses and their impact on disease progression, human epidemiology, as well as targeted studies in nonhuman primates. African research teams as well as cohorts of healthy volunteers and HIV-infected individuals have contributed to HIV vaccine research and development in many important ways. It is essential that this work continue to speed the development and deployment of a vaccine suitable for African populations.

HIV type 1 molecular epidemiology among high-risk clients attending the Thai Red Cross Anonymous Clinic in Bangkok, Thailand

Several studies have reported an increasing number of non-CRF01_AE infections in high-risk groups in Thailand suggesting a more complex HIV-1 epidemic. This study assessed the complexity of the HIV epidemic among high-risk clients tested for HIV-1 at the Thai Red Cross Anonymous Clinic (TRCAC) between July 1, 2006 and February 28, 2007. HIV-1 genotypes were determined from plasma of infected subjects (n = 401) by the multiregion hybridization assay (MHAbce, v.2). Univariate and multivariate logistic regression analyses were used to determine risk factors associated with HIV prevalence and non-CRF01_AE infection. The estimated overall HIV prevalence was 14.1%: 25.3% among men who have sex with men (MSM), 18.4% among heterosexual women, and 9.6% among heterosexual men. Among the risk factors found to be associated with HIV prevalence were age (25-29 years), risk behavior (MSM), marital status (not single), education (less than high school), and inconsistent condom use. Overall, non-CRF01_AE strains accounted for 18.9% of the infections: 25.3% among MSM and 14.8% and 20.4% among heterosexual women and men, respectively. Our results indicate a concentrated and genetically complex HIV epidemic among Thai MSM. These findings advocate for targeted intervention and prevention measures among high-risk populations in Thailand.

CLSI-derived hematology and biochemistry reference intervals for healthy adults in eastern and southern Africa

BACKGROUND

Clinical laboratory reference intervals have not been established in many African countries, and non-local intervals are commonly used in clinical trials to screen and monitor adverse events (AEs) among African participants. Using laboratory reference intervals derived from other populations excludes potential trial volunteers in Africa and makes AE assessment challenging. The objective of this study was to establish clinical laboratory reference intervals for 25 hematology, immunology and biochemistry values among healthy African adults typical of those who might join a clinical trial.

METHODS AND FINDINGS

Equal proportions of men and women were invited to participate in a cross sectional study at seven clinical centers (Kigali, Rwanda; Masaka and Entebbe, Uganda; two in Nairobi and one in Kilifi, Kenya; and Lusaka, Zambia). All laboratories used hematology, immunology and biochemistry analyzers validated by an independent clinical laboratory. Clinical and Laboratory Standards Institute guidelines were followed to create study consensus intervals. For comparison, AE grading criteria published by the U.S. National Institute of Allergy and Infectious Diseases Division of AIDS (DAIDS) and other U.S. reference intervals were used. 2,990 potential volunteers were screened, and 2,105 (1,083 men and 1,022 women) were included in the analysis. While some significant gender and regional differences were observed, creating consensus African study intervals from the complete data was possible for 18 of the 25 analytes. Compared to reference intervals from the U.S., we found lower hematocrit and hemoglobin levels, particularly among women, lower white blood cell and neutrophil counts, and lower amylase. Both genders had elevated eosinophil counts, immunoglobulin G, total and direct bilirubin, lactate dehydrogenase and creatine phosphokinase, the latter being more pronounced among women. When graded against U.S. -derived DAIDS AE grading criteria, we observed 774 (35.3%) volunteers with grade one or higher results; 314 (14.9%) had elevated total bilirubin, and 201 (9.6%) had low neutrophil counts. These otherwise healthy volunteers would be excluded or would require special exemption to participate in many clinical trials.

CONCLUSIONS

To accelerate clinical trials in Africa, and to improve their scientific validity, locally appropriate reference ranges should be used. This study provides ranges that will inform inclusion criteria and evaluation of adverse events for studies in these regions of Africa.