Assessing the safety, impact and effectiveness of RTS,S/AS01E malaria vaccine following its introduction in three sub-Saharan African countries: methodological approaches and study set-up.

BACKGROUND: Following a 30-year development process, RTS,S/AS01E (GSK, Belgium) is the first malaria vaccine to reach Phase IV assessments. The World Health Organization-commissioned Malaria Vaccine Implementation Programme (MVIP) is coordinating the delivery of RTS,S/AS01E through routine national immunization programmes in areas of 3 countries in sub-Saharan Africa. The first doses were given in the participating MVIP areas in Malawi on 23 April, Ghana on 30 April, and Kenya on 13 September 2019. The countries participating in the MVIP have little or no baseline incidence data on rare diseases, some of which may be associated with immunization, a deficit that could compromise the interpretation of possible adverse events reported following the introduction of a new vaccine in the paediatric population. Further, effects of vaccination on malaria transmission, existing malaria control strategies, and possible vaccine-mediated selective pressure on Plasmodium falciparum variants, could also impact long-term malaria control. To address this data gap and as part of its post-approval commitments, GSK has developed a post-approval plan comprising of 4 complementary Phase IV studies that will evaluate safety, effectiveness and impact of RTS,S/AS01E through active participant follow-up in the context of its real-life implementation. METHODS: EPI-MAL-002 (NCT02374450) is a pre-implementation safety surveillance study that is establishing the background incidence rates of protocol-defined adverse events of special interest. EPI-MAL-003 (NCT03855995) is an identically designed post-implementation safety and vaccine impact study. EPI-MAL-005 (NCT02251704) is a cross-sectional pre- and post-implementation study to measure malaria transmission intensity and monitor the use of other malaria control interventions in the study areas, and EPI-MAL-010 (EUPAS42948) will evaluate the P. falciparum genetic diversity in the periods before and after vaccine implementation. CONCLUSION: GSK's post-approval plan has been designed to address important knowledge gaps in RTS,S/AS01E vaccine safety, effectiveness and impact. The studies are currently being conducted in the MVIP areas. Their implementation has provided opportunities and posed challenges linked to conducting large studies in regions where healthcare infrastructure is limited. The results from these studies will support ongoing evaluation of RTS,S/AS01E's benefit-risk and inform decision-making for its potential wider implementation across sub-Saharan Africa.

Long-term safety and immunogenicity of the M72/AS01E candidate tuberculosis vaccine in HIV-positive and -negative Indian adults: Results from a phase II randomized controlled trial.

OBJECTIVES: To assess the long-term safety and immunogenicity of the M72/ Adjuvant System (AS01E) candidate tuberculosis (TB) vaccine up to 3 years post-dose 2 (Y3) in human immunodeficiency virus (HIV)-positive (HIV+) and HIV-negative (HIV-) Indian adults. METHODS: This phase II, double-blind, randomised, controlled clinical trial (NCT01262976) was conducted at YRG CARE Medical Centre, in Chennai, India, between January 2011 and June 2015.Three cohorts (HIV+ participants stable on antiretroviral therapy [ART; HIV+ART+], HIV+ ART-naïve [HIV+ART-], and HIV- participants) were randomised (1:1) to receive 2 doses of M72/AS01E (M72/AS01E groups) or saline (control groups) 1 month apart and were followed up toY3. Latent TB infection was assessed at screening using an interferon-gamma (IFN-γ) release assay (IGRA). Safety and immunogenicity results up to Y1 post-vaccination were reported elsewhere. Here, we report serious adverse events (SAEs), humoral and cell-mediated immune (CMI) responses to M72 recorded at Y2 and Y3. RESULTS: Of 240 enrolled and vaccinated participants, 214 completed the long-term follow-up part of the study.In addition to SAEs previously described, between Y1 and Y2 1 M72/AS01E recipient in the HIV+ART+ cohort reported 2 SAEs (sinus cavernous thrombosis and gastroenteritis) that were not considered as causally related to the study vaccine.Vaccination elicited persistent humoral immune responses against M72. At Y3, seropositivity rates were 97.1%, 66.7%, and 97.3% and geometric mean concentrations (GMCs) were 22.0  ELISA units (EU)/mL, 4.9 EU/mL, and 24.3 EU/mL in the HIV+ART+, HIV+ART-, and HIV- cohorts, respectively. Humoral immune response was lowest in the HIV+ART- cohort.In M72/AS01E recipients, no notable decrease in the frequency of M72-specific CD4 T-cells expressing ≥2 immune markers among interleukin-2 (IL-2), IFN-γ, tumour necrosis factor alpha (TNF-α) and CD40 ligand (CD40L) was observed at Y3 post-vaccination. Median values (interquartile range) of 0.35% (0.13-0.49), 0.05% (0.01-0.10), and 0.15% (0.09-0.22) were recorded in the HIV+ART+, HIV+ART- and HIV- cohorts, respectively. CD4 T-cell response was lowest in the HIV+ART- cohort.No CD8 T-cell response was observed. CONCLUSION: The cellular and humoral immune responses induced by M72/AS01E in HIV+ and HIV- adults persisted up to Y3 post-vaccination. No safety concerns were raised regarding administration of M72/AS01E to HIV+ adults. CLINICAL TRIAL REGISTRATION: NCT01262976 (www.clinicaltrials.gov).