Clinical tolerability of artesunate-amodiaquine versus comparator treatments for uncomplicated falciparum malaria: an individual-patient analysis of eight randomized controlled trials in sub-Saharan Africa

Meta-analysis of the global distribution of clinically relevant CYP2C8 alleles and their inferred functional consequences

BACKGROUND

CYP2C8 is responsible for the metabolism of 5% of clinically prescribed drugs, including antimalarials, anti-cancer and anti-inflammatory drugs. Genetic variability is an important factor that influences CYP2C8 activity and modulates the pharmacokinetics, efficacy and safety of its substrates.

RESULTS

We profiled the genetic landscape of CYP2C8 variability using data from 96 original studies and data repositories that included a total of 33,185 unrelated participants across 44 countries and 43 ethnic groups. The reduced function allele CYP2C8*2 was most common in West and Central Africa with frequencies of 16-36.9%, whereas it was rare in Europe and Asia (< 2%). In contrast, CYP2C8*3 and CYP2C8*4 were common throughout Europe and the Americas (6.9-19.8% for *3 and 2.3-7.5% for *4), but rare in African and East Asian populations. Importantly, we observe pronounced differences (> 2.3-fold) between neighboring countries and even between geographically overlapping populations. Overall, we found that 20-60% of individuals in Africa and Europe carry at least one CYP2C8 allele associated with reduced metabolism and increased adverse event risk of the anti-malarial amodiaquine. Furthermore, up to 60% of individuals of West African ancestry harbored variants that reduced the clearance of pioglitazone, repaglinide, paclitaxel and ibuprofen. In contrast, reduced function alleles are only found in < 2% of East Asian and 8.3-12.8% of South and West Asian individuals.

CONCLUSIONS

Combined, the presented analyses mapped the genetic and inferred functional variability of CYP2C8 with high ethnogeographic resolution. These results can serve as a valuable resource for CYP2C8 allele frequencies and distribution estimates of CYP2C8 phenotypes that could help identify populations at risk upon treatment with CYP2C8 substrates. The high variability between ethnic groups incentivizes high-resolution pharmacogenetic profiling to guide precision medicine and maximize its socioeconomic benefits, particularly for understudied populations with distinct genetic profiles.

Community-based management of a five-arm randomised clinical trial in COVID-19 outpatients in South Africa: challenges and opportunities

BACKGROUND

Repeated COVID-19 waves and corresponding mitigation measures have impacted health systems globally with exceptional challenges. In response to the pandemic, researchers, regulators, and funders rapidly pivoted to COVID-19 research activities. However, many clinical drug studies were not completed, due to often complex and rapidly evolving research conditions.

METHODS

We outline our experience of planning and managing a randomised, adaptive, open-label, phase 2 clinical trial to evaluate the safety and efficacy of four repurposed drug regimens versus standard-of-care (SOC) in outpatients with 'mild to moderate' COVID-19 in Johannesburg, South Africa, in the context of a partnership with multiple stakeholders. The study was conducted between 3 September 2020 and 23 August 2021 during changing COVID-19 restrictions, significant morbidity and mortality waves, and allied supply line, economic, and political instability.

RESULTS

Our clinical study design was pragmatic, including low-risk patients who were treated open label. There was built-in flexibility, including provision for some sample size adjustment and a range of secondary efficacy outcomes. Barriers to recruitment included the timing of waves, staff shortages due to illness, late presentation of patients, COVID-19 misinformation, and political unrest. Mitigations were the use of community health workers, deployment of mobile clinical units, and simplification of screening. Trial management required a radical reorganisation of logistics and processes to accommodate COVID-19 restrictions. These included the delivery of staff training and monitoring remotely, electronic consent, patient training and support to collect samples and report data at home, and the introduction of tele-medicine. These measures were successful for data collection, safe, and well received by patients.

CONCLUSION

Completing a COVID-19 trial in outpatients during the height of the pandemic required multiple innovations in nearly every aspect of clinical trial management, a high commitment level from study staff and patients, and support from study sponsors. Our experience has generated a more robust clinical research infrastructure, building in efficiencies to clinical trial management beyond the pandemic.

Safety and efficacy of four drug regimens versus standard-of-care for the treatment of symptomatic outpatients with COVID-19: A randomised, open-label, multi-arm, phase 2 clinical trial

Background

This exploratory study investigated four repurposed anti-infective drug regimens in outpatients with COVID-19.

Methods

This phase 2, single centre, randomised, open-label, clinical trial was conducted in South Africa between 3rd September 2020 and 23rd August 2021. Symptomatic outpatients aged 18–65 years, with RT-PCR confirmed SARS-CoV-2 infection were computer randomised (1:1:1:1:1) to standard-of-care (SOC) with paracetamol, or SOC plus artesunate-amodiaquine (ASAQ), pyronaridine-artesunate (PA), favipiravir plus nitazoxanide (FPV + NTZ), or sofosbuvir-daclatasvir (SOF-DCV). The primary endpoint was the incidence of viral clearance, i.e., the proportion of patients with a negative SARS-CoV-2 RT-PCR on day 7, compared to SOC using a log-binomial model in the modified intention-to-treat (mITT) population.

Findings

The mITT population included 186 patients: mean age (SD) 34.9 (10.3) years, body weight 78.2 (17.1) kg. Day 7 SARS-CoV-2 clearance rates (n/N; risk ratio [95% CI]) were: SOC 34.2% (13/38), ASAQ 38.5% (15/39; 0.80 [0.44, 1.47]), PA 30.3% (10/33; 0.69 [0.37, 1.29]), FPV + NTZ 27.0% (10/37; 0.60 [0.31, 1.18]) and SOF-DCV 23.5% (8/34; 0.47 [0.22, 1.00]). Three lower respiratory tract infections occurred (PA 6.1% [2/33]; SOF-DCV 2.9% [1/34]); two required hospitalisation (PA, SOF-DCV). There were no deaths. Adverse events occurred in 55.3% (105/190) of patients, including one serious adverse event (pancytopenia; FPV + NTZ).

Interpretation

There was no statistical difference in viral clearance for any regimen compared to SOC. All treatments were well tolerated.

Funding

10.13039/501100004167Medicines for Malaria Venture, with funding from the UK Foreign, Commonwealth and Development Office, within the Covid-19 Therapeutics Accelerator in partnership with 10.13039/100004440Wellcome, the 10.13039/100000865Bill and Melinda Gates Foundation, and Mastercard.

Liver Function Test Abnormalities in Experimental and Clinical Plasmodium vivax Infection

Liver transaminase elevations after treatment in malaria volunteer infection studies (VISs) have raised safety concerns. We investigated transaminase elevations from two human Plasmodium vivax VISs where subjects were treated with chloroquine (n = 24) or artefenomel (n = 8) and compared them with studies in Thailand (n = 41) and Malaysia (n = 76). In the VISs, alanine transaminase (ALT) increased to ≥ 2.5 × upper limit of normal (ULN) in 11/32 (34%) volunteers, peaking 5–8 days post-treatment. Transaminase elevations were asymptomatic, were not associated with elevated bilirubin, and resolved by day 42. The risk of an ALT ≥ 2.5 × ULN increased more than 4-fold (odds ratio [OR] 4.28; 95% CI: 1.26–14.59; P = 0.02) for every log₁₀ increase in the parasite clearance burden (PCB), defined as the log-fold reduction in parasitemia 24 hours post-treatment. Although an elevated ALT ≥ 2.5 × ULN was more common after artefenomel than after chloroquine (5/8 [63%] versus 6/24 [25%]; OR 5.0; 95% CI: 0.91–27.47; P = 0.06), this risk disappeared when corrected for PCB. Peak ALT also correlated with peak C-reactive protein (R = 0.44; P = 0.012). Elevations in ALT (≥ 2.5 × ULN) were less common in malaria-endemic settings, occurring in 1/41 (2.5%) Thai patients treated with artefenomel, and in none of 76 Malaysians treated with chloroquine or artemisinin combination therapy. Post-treatment transaminase elevations are common in experimental P. vivax infection but do not appear to impact on participant safety. Although the mechanism of these changes remains uncertain, host inflammatory response to parasite clearance may be contributory.

Artesunate/Amodiaquine-Induced Acute Extrapyramidal Reactions in Children and Younger Adults: Case Series Assessment

INTRODUCTION

Several studies conducted in African countries reported the artesunate and amodiaquine (AS/AQ) tablet as a safe and well-tolerated anti-malarial drug in children and younger adults. The aim of this case series assessment was to assess the causal relationship between the AS/AQ tablet and extrapyramidal reactions in children and younger adults and to investigate the factor(s) predisposing to the adverse drug reactions.

METHODS

The causal relationship of all the cases was first assessed individually using the Naranjo Probability Scale and then subjected to a case series assessment using Austin Bradford-Hill criteria.

RESULTS

A total of 43 acute extrapyramidal reactions associated with the AS/AQ tablet were reported between 2012 and 16 November, 2015 to the Eritrean Pharmacovigilance Centre. The causality was found to be probable or highly probable for 33 (76.7 %) of the cases and the rest (10; 23.3 %) of the cases had a possible causal association. The extrapyramidal reactions had more or less similar clinical features in most of the cases and were characterized by abnormal involuntary contractions of muscles. The median age and body weight of the cases were 15 years and 40 kg, respectively, and 70 % of them were males. 90.7% of the reactions manifested in children and younger adults (aged <26 years). In most of the cases, reactions manifested in the third day from the start of treatment and 88.3 % of cases were hospitalized.

CONCLUSION

The causal relationship between the AS/AQ tablet and extrapyramidal reactions in children and younger adults was found to be apparent and possibly owing to dose accumulation or an overdose of amodiaquine.

Comparison of anti-malarial drugs efficacy in the treatment of uncomplicated malaria in African children and adults using network meta-analysis

Background

Artemisinin-based combination therapy (ACT) and novel drug combinations are available and used in African countries to treat uncomplicated malaria. Network meta-analysis methods are rarely and poorly applied for the comparison of their efficacies. This method was applied on a set of randomized controlled trials to illustrate its usefulness.

Methods

A literature review available in Pubmed was conducted in July 2016. Eligible studies, conducted in sub-Saharan Africa, published between 2002 and 2016, focused on randomized controlled trials of at least two artemisinin-based combinations to treat uncomplicated malaria in children and adults. Agglomerate data were: the number of PCR-corrected adequate clinical and parasitological response (ACPR) on day 28, used as the primary endpoint in all interventions, the number of participants and the list of treatments. A Bayesian random effect meta-analysis using a binary outcome was the method to compare the efficacy. Ranking measure was used to obtain a hierarchy of the competing interventions.

Results

In total, 76 articles were included; 13 treatment regimens were involved and tested in 36,001 patients. Using artemether–lumefantrine (AL) as the common comparator for the entire network, 12 relative treatment effects were estimated and indirect comparisons were obtained. Dihydroartemisinin–piperaquine (DHAP) was shown to be more effective than AL (odds ratio [OR] = 1.92; 95% CI 1.30–2.82; 19,163 patients), ASAQ (OR = 1.70; 95% CI 1.10–2.64; 14,433 patients), and amodiaquine–sulfadoxine–pyrimethamine (AQSP): OR = 2.20; 95% CI 1.21–3.96; 8863 patients. Artesunate–amodiaquine (ASAQ) was comparable to AL (OR = 1.11; 95% CI 0.84–1.45; 21,235 patients). No significant difference was found between artesunate and mefloquine (ASMQ) and AL (OR = 1.20; 95% CI = 0.52-2.8; 13,824 participants). According to treatment ranking, among the WHO-recommended ACT medicines, DHAP was shown to be the most efficacious.

Conclusions

Based on the available evidence, this study demonstrated the superiority of DHAP among currently recommended artemisinin-based combinations. The application of the methods described here may be helpful to gain better understanding of treatment efficacy and improve future decisions. However, more data are needed to allow robust conclusions about the results in comparison with novel drugs. Further surveillance of the efficacy of anti-malarial drugs and clinical trials are needed to closely follow the evolution of the epidemiology of drug-resistant malaria in Africa.

Electronic supplementary material

The online version of this article (doi:10.1186/s12936-017-1963-0) contains supplementary material, which is available to authorized users.

Effect of Artesunate-Amodiaquine on Mortality Related to Ebola Virus Disease

BACKGROUND

Malaria treatment is recommended for patients with suspected Ebola virus disease (EVD) in West Africa, whether systeomatically or based on confirmed malaria diagnosis. At the Ebola treatment center in Foya, Lofa County, Liberia, the supply of artemether-lumefantrine, a first-line antimalarial combination drug, ran out for a 12-day period in August 2014. During this time, patients received the combination drug artesunate-amodiaquine; amodiaquine is a compound with anti-Ebola virus activity in vitro. No other obvious change in the care of patients occurred during this period.

METHODS

We fit unadjusted and adjusted regression models to standardized patient-level data to estimate the risk ratio for death among patients with confirmed EVD who were prescribed artesunate-amodiaquine (artesunate-amodiaquine group), as compared with those who were prescribed artemether-lumefantrine (artemether-lumefantrine group) and those who were not prescribed any antimalarial drug (no-antimalarial group).

RESULTS

Between June 5 and October 24, 2014, a total of 382 patients with confirmed EVD were admitted to the Ebola treatment center in Foya. At admission, 194 patients were prescribed artemether-lumefantrine and 71 were prescribed artesunate-amodiaquine. The characteristics of the patients in the artesunate-amodiaquine group were similar to those in the artemether-lumefantrine group and those in the no-antimalarial group. A total of 125 of the 194 patients in the artemether-lumefantrine group (64.4%) died, as compared with 36 of the 71 patients in the artesunate-amodiaquine group (50.7%). In adjusted analyses, the artesunate-amodiaquine group had a 31% lower risk of death than the artemether-lumefantrine group (risk ratio, 0.69; 95% confidence interval, 0.54 to 0.89), with a stronger effect observed among patients without malaria.

CONCLUSIONS

Patients who were prescribed artesunate-amodiaquine had a lower risk of death from EVD than did patients who were prescribed artemether-lumefantrine. However, our analyses cannot exclude the possibility that artemether-lumefantrine is associated with an increased risk of death or that the use of artesunate-amodiaquine was associated with unmeasured patient characteristics that directly altered the risk of death.

Fighting the good fight: the role of militaries in malaria elimination in Southeast Asia

Despite significant progress in malaria control in the Greater Mekong Subregion (GMS), malaria is still endemic, with more than 30 million people infected annually. Important gaps remain in case management, service delivery, prevention, and vector control, particularly in hard-to-reach mobile populations. Rapidly evolving drug resistance has created a new urgency to move aggressively toward elimination. However, no clear and cost-effective strategy has been identified. Although GMS militaries are under-recognized as a malaria transmission reservoir, they are an important focal point for elimination activities, given their high mobility, frequent malaria exposure, and potential for asymptomatic carriage. At the same time, military organizational capacity and proximity to other mobile populations could facilitate elimination efforts if relevant political barriers could be overcome. Here, we review considerations for military involvement in regional malaria elimination efforts.

Malaria: an update on current chemotherapy

INTRODUCTION

Chemotherapy of malaria has become a rapidly changing field. Less than two decades ago, treatment regimens were increasingly bound to fail due to emerging drug resistance against 4-aminoquinolines and sulfa compounds. By now, artemisinin-based combination therapies (ACTs) constitute the standard of care for uncomplicated falciparum malaria and are increasingly also taken into consideration for the treatment of non-falciparum malaria.

AREAS COVERED

This narrative review provides an overview of the state-of-art antimalarial drug therapy, highlights the global portfolio of current Phase III/IV clinical trials and summarizes current developments.

EXPERT OPINION

Malaria chemotherapy remains a dynamic field, with novel drugs and drug combinations continuing to emerge in order to outpace the development of large-scale drug resistance against the currently most important drug class, the artemisinin derivatives. More randomized controlled studies are urgently needed especially for the treatment of malaria in first trimester pregnant women. ACTs should be used for the treatment of imported malaria more consequently. Gaining sufficient efficacy and safety information on ACT use for non-falciparum species including Plasmodium ovale and malariae should be a research priority. Continuous investment into malaria drug development is a vital factor to combat artemisinin resistance and successfully improve malaria control toward the ultimate goal of elimination.

In vivo efficacy of artemether-lumefantrine and artesunate-amodiaquine for the treatment of uncomplicated falciparum malaria in children: a multisite, open-label, two-cohort, clinical trial in Mozambique

Background

Mozambique adopted artemisinin-based combination therapy (ACT) for the treatment of uncomplicated Plasmodium falciparum malaria in the year 2006, and since 2009 artemether-lumefantrine (AL) and artesunate-amodiaquine (ASAQ) have been proposed as alternative first-line treatments. A multicentre study was conducted in five sites across the country to assess the in vivo efficacy and tolerability of these two drugs.

Methods

Children aged six to 59 months with uncomplicated malaria were recruited between June 2011 and January 2012 in five sites across Mozambique (Montepuez, Dondo, Tete, Chokwe, and Manhiça), and treated with AL or ASAQ in a non-randomized study. Follow-up was organized following standard WHO recommendations for in vivo studies, and included daily visits during the three-day-long supervised treatment course, followed by weekly visits up to day 28. The study primary outcome was the day 28 PCR-corrected early treatment failure (ETF), late clinical failure (LCF), late parasitological failure (LPF), and adequate clinical and parasitological response (ACPR). PCR was performed centrally for all cases of recurrent parasitaemia from day 7 onwards to distinguish recrudescence from re-infection.

Results

Four-hundred and thirty-nine (AL cohort; five sites) and 261 (ASAQ cohort, three sites) children were recruited to the study. Day 28 PCR-corrected efficacy for AL was 96.0% (335/339; 95% CI: 93.4-97.8), while for ASAQ it was 99.6% (232/233; 95% CI: 97.6-99.9). The majority of recurring parasitaemia cases throughout follow-up were shown to be re-infections by PCR. Both drugs were well tolerated, with the most frequent adverse event being vomiting (AL 4.5% [20/439]; ASAQ 9.6% [25/261]) and no significant events deemed related to the study drugs.

Conclusion

This study confirms that both AL and ASAQ remain highly efficacious and well tolerated for the treatment of uncomplicated malaria in Mozambican children. Studies such as these should be replicated regularly in the selected surveillance sentinel sites to continuously monitor the efficacy of these drugs and to rapidly detect any potential signs of declining efficacy to ACT, the mainstay of malaria treatment.

Tolerability and safety of artesunate-amodiaquine and artemether-lumefantrine fixed dose combinations for the treatment of uncomplicated Plasmodium falciparum malaria: two open-label, randomized trials in Nimba County, Liberia

BACKGROUND

Safety surveillance of widely used artemisinin-based combination therapy (ACT) is essential, but tolerability data in the over five years age group are largely anecdotal.

METHODS

Two open-label, randomized trials were conducted in Nimba County, Liberia: i) the main tolerability trial with 1,000 Plasmodium falciparum malaria patients aged over five years (Study-T), and, ii) an efficacy trial with a secondary objective of collecting tolerability data among 300 children age six to 59 months (Study-E). In both studies patients were randomized to fixed-dose artesunate-amodiaquine (ASAQ Winthrop®) or artemether-lumefantrine (AL, Coartem®), respectively. Clinical- and laboratory-adverse events (AEs) were recorded until day 28.

RESULTS

Study-T: most patients experienced at least one AE. Severe AEs were few, primarily asymptomatic blood system disorders or increased liver enzyme values. No treatment or study discontinuation occurred. Mild or moderate fatigue (39.8% vs 16.3%, p < 0.001), vomiting (7.1% vs 1.6%, p < 0.001), nausea (3.2% vs 1.0%, p = 0.01), and anaemia (14.9% vs 9.8%, p = 0.01) were more frequently recorded in the ASAQ versus AL arm. Study-E: mild or moderate AEs were common, including anaemia, fatigue, vomiting or diarrhoea. The few severe events were asymptomatic blood system disorders and four clinical events (pneumonia, malaria, vomiting and stomatitis).

CONCLUSION

Both ASAQ and AL were well tolerated in patients of all age groups. No unexpected AEs occurred. Certain mild or moderate AEs were more frequent in the ASAQ arm. Standardised safety surveillance should continue for all forms of ACT.

TRIAL REGISTRATION

The protocols were registered with Current Controlled Trials, under the identifier numbers ISRCTN40020296, ISRCTN51688713, (http://www.controlled-trials.com).

An artesunate-containing antimalarial treatment regimen did not suppress cytomegalovirus viremia

BACKGROUND

Additional drugs are needed for the treatment of cytomegalovirus (CMV) infection. Artesunate is an antimalarial drug that has activity against CMV in vitro and in a rodent model. Only a small number of case reports are available describing the clinical effects of artesunate on CMV infection, and these yielded inconsistent results.

OBJECTIVE

To evaluate the effect of artesunate on CMV infection, using blood samples collected from children who participated in malaria treatment trials.

STUDY DESIGN

Quantitative CMV DNA PCR was performed on dried blood spots collected from 494 Ugandan children, who were randomized either to artesunate plus amodiaquine or sulfadoxine-pyrimethamine plus amodiaquine for acute malaria infection. Poisson regression was used to compare treatment regimens with respect to the change in the frequency and quantity of CMV detected that occurred before and after treatment.

RESULTS

CMV was detected in 11.4% of children immediately prior to treatment and 10.7% 3 days later (p=0.70). The average quantity of CMV was 0.30 log10 copies per million cells higher on day 3 than at treatment initiation (95% CI 0.01-0.58, p=0.041). There was no measurable difference in either the frequency or quantity of CMV detected in blood between children randomized to the two treatment arms.

CONCLUSIONS

A standard 3-day artesunate-containing antimalarial regimen had no detectable effect on CMV viremia in children with malaria. Longer treatment courses and/or higher doses of artesunate than those routinely used for malaria may be required for effective treatment of CMV infection.

Safety monitoring of artemisinin combination therapy through a national pharmacovigilance system in an endemic malaria setting

Background

The National Malaria Control Programme in Senegal, introduced since 2006, artemisinin-based combination therapy (ACT administration) for the treatment of uncomplicated malaria cases. In this framework, an anti-malarial pharmacovigilance plan was developed and implemented in all public health services. This study investigated the occurrence of Adverse Drug Events (ADEs) after ACT.

Methods

The study was conducted between January 2007 and December 2009. It was based on spontaneous reports of ADEs in public health facilities. Data on patient demographic characteristics, dispensing facility, adverse signs and symptoms and causality were collected from a total of 123 patients.

Results

The age range of these patients was six months to 93 years with a mean of 25.9 years. Of the reported symptoms, 46.7% were related to the abdomen and the digestive system. Symptoms related to the nervous system, skin and subcutaneous tissue, circulatory and respiratory systems and general symptoms and signs were 7%, 9.7%, 3.5% and 31.3%, respectively. Causality results linked 14.3% of symptoms to Falcimon® (Artesunate-Amodiaquine) with certainty. Effects were classified as mild and severe in 69.1% and 7.3% of cases respectively while 23.6% were serious. All patients with serious ADEs were hospitalized. One death was reported in a patient who had taken 24 pills at once.

Conclusion

These results confirm the need to develop and implement pharmacovigilance systems in malaria endemic countries in order to monitor the safety of anti-malarial treatments.

Anti-malarial drug safety information obtained through routine monitoring in a rural district of South-Western Senegal

Background

Knowing the safety profile of anti-malarial treatments in routine use is essential; millions of patients receive now artemisinin combination therapy (ACT) annually, but the return on information through current systems is as yet inadequate. Cohort event monitoring (CEM) is a WHO (World Health Organization)-recommended practice; testing its performance and feasibility in routine practice in malaria-endemic is important.

Methods

A nine-year CEM-based study of the safety of artesunate-amodiaquine (ASAQ) at five peripheral health facilities in a rural district of South-western Senegal. Staff (nurses, health workers) were trained to collect actively and systematically information on the patient, treatment and events on a purposely designed questionnaire. The occurrence and severity of events was collected before, during and after treatment up to 28 days in order to generate information on all adverse events (AEs) as well as treatment-emerging signs/symptoms (TESS). Laboratory tests (haematology, liver and renal) was planned for at least 10% of cases.

Results

During 2001–2009, 3,708 parasitologically-confirmed malaria cases (mean age = 16.0 ± 12.7 years) were enrolled (26% and 52% of all and parasitologically-confirmed ASAQ treatments, respectively). Treatment was supervised in 96% of cases. Products changed over time: 49% were a loose combination of individually-packaged products (available 2001–03), 42% co-blistered products (2004–09) and 9% a fixed-dose co-formulation (2006–09); dosing was age-based for 42%, weight-based for 58%. AS and AQ were correctly dosed in 97% and 82% of cases with the loose and 93% and 86% with the fixed combination, but only 50% and 42% with the co-blistered product.

Thirty-three per cent (33%) of patients had at least one sign/symptom pre-treatment, 12% had at least one AE and 9% a TESS (total events 3,914, 1,144 and 693, respectively). AEs overestimated TESS by 1.2-2 fold (average 1.7). Changes in laboratory value were insignificant. Over-dosing more than doubled the risk of TESS, though statistical significance was reached only during 2003–2007. The incidence of serious events (including death) was five per thousand.

Conclusions

The study was successful in quantifying and characterizing known reactions and has benchmarking value. Health staff performance varied. Investments in training, motivating and providing a quality control system would be needed. The study proved that a CEM-based system is feasible in this setting but more research is needed to assess whether it is sustainable and what conditions would make it cost-effective, including the amount and quality of data generated, and the use thereof for decision-making.