A Randomized Trial to Compare the Safety, Tolerability, and Effectiveness of 3 Antimalarial Regimens for the Prevention of Malaria in Nigerian Patients With Sickle Cell Disease

Treating sickle cell disease in resource-limited sub-Saharan Africa: recent strategies and recommendations in addressing the gaps for the provision of evidence-based management

INTRODUCTION

The management of Sickle cell disease (SCD) in sub-Saharan Africa (SSA) suffers from the lack of universal infant and population screening, inadequate access to standard treatment and poor public health prioritization amidst unstable political systems.

AREAS COVERED

The state of evidencebased management of SCD in SSA was investigated including sustainability of international funding agencies.

EXPERT OPINION

Current efforts are fragmentary along languages lines; sometimes driven by the funder's objectives and not the national agenda. The review highlighted the role of internal and external partnerships such as SPARCO, ARISE, CONSA, as well as technology-based support for the implementation of evidence-based care for SCD. We advocate for increased funding to implement SCD comprehensive care in line with the WHO SCD Framework for Primary, Secondary, Tertiary and Specialist Comprehensive Care at state and national level. To achieve this objective, it is important that SCD, as a leading non-communicable disease in Africa, be mandated as a standing agenda for the National Council of Ministers at the African Union, WHO and other regional bodies in Africa.

Artesunate-mefloquine therapy for uncomplicated Plasmodium falciparum malaria: an updated systematic review and meta-analysis of efficacy and safety

To provide a continuous update on the safety and efficacy of artesunate-mefloquine (ASMQ) compared with other artemisinin combination therapy (ACT) schemes used in the treatment of uncomplicated malaria caused by Plasmodium falciparum, this study updated and expanded the results of the systematic literature review published in 2016. Only randomised controlled clinical trials published from 1 January 2001 to 12 June 2023 from five databases were included in this study. The results related to efficacy, expressed through RR, were summarized in meta-analyses, performed according to the compared ACTs and with the intention-to-treat and per-protocol analyses. The results related to safety were synthesized in a descriptive manner. Thirty-two studies were included, of which 24 had been analysed in the 2016 review and eight new ones were added. Although the methodological quality of most studies was considered moderate, the body of evidence gathered indicates that ASMQ continues to be safe and effective for the treatment of uncomplicated infections caused by P. falciparum compared with other ACTs. However, the inclusion of two new studies, which identified failure rates exceeding 10%, suggests a possible reduction in the efficacy of ASMQ in the analysed locations. The incidence of serious adverse effects, such as seizure, encephalopathy and cardiac arrhythmia, was infrequent in both the ASMQ group and the comparison groups. After including new evidence, ASMQ is still recommended as a first-line treatment of uncomplicated malaria caused by P. falciparum, although local aspects need to be considered.

Evidence-based interventions for reducing sickle cell disease-associated morbidity and mortality in sub-Saharan Africa: A scoping review

Objective

Sickle cell disease is a lifelong illness affecting millions of people globally, but predominantly burdensome in sub-Saharan Africa, where most affected children do not live to adulthood, despite available evidence-based interventions that reduce the disease burden in high-income countries.

Method

We reviewed studies evaluating evidence-based interventions that decrease sickle cell disease-related morbidity and mortality among children living in sub-Saharan Africa. We used the Joanna Briggs scoping review methodological framework and grouped identified evidence-based interventions into preventative pharmacotherapeutic agents, newborn screening and comprehensive healthcare, disease-modifying agents, nutritional supplementation, systemic treatment, supportive agents and patient/carer/population education.

Results

We included 36 studies: 18 randomized controlled trials, 11 observational studies, 5 before-and-after studies and 2 economic evaluation studies, with most of the studies performed in West African countries. Included studies suggest evidence-based interventions effectively to reduce the common morbidities associated with sickle cell disease such as stroke, vaso-occlusive crisis, acute chest syndrome, severe anaemia and malaria infection. Evidence-based interventions also improve survival among study participants. Specifically, our review shows hydroxyurea increases haemoglobin and foetal haemoglobin levels, a finding with practical implications given the challenges with blood transfusion in this setting. The feasibility of implementing individual interventions is hampered by challenges such as affordability, accessibility and the availability of financial and human resources.

Conclusion

Our review suggests that regular use of low-dose hydroxyurea therapy, sulphadoxine-pyrimethamine chemoprophylaxis, L-arginine and Omega-3 fatty acid supplementation and establishment of specialist stand-alone sickle cell clinics could reduce the sickle cell disease-associated morbidity and mortality in sub-Saharan Africa countries.

Sickle Cell Disease in Children and Adolescents: A Review of the Historical, Clinical, and Public Health Perspective of Sub-Saharan Africa and Beyond

Sickle cell disease (SCD) is an umbrella term for a group of life-long debilitating autosomal recessive disorders that are caused by a single-point mutation (Glu→Val) that results in polymerization of hemoglobin (Hb) and reversible sickle-shape deformation of erythrocytes. This leads to increased hemolysis of erythrocytes and microvascular occlusion, ischemia-reperfusion injury, and tissue infarction, ultimately causing multisystem end-organ complications. Sickle cell anemia (HbSS) is the most common and most severe genotype of SCD, followed by HbSC, HbSβ 0thalassemia, HbSβ+thalassemia, and rare and benign genotypes. Clinical manifestations of SCD occur early in life, are variable, and are modified by several genetic and environmental factors. Nearly 500 children with SCD continue to die prematurely every day, due to delayed diagnosis and/or lack of access to comprehensive care in sub-Saharan Africa (SSA), a trend that needs to be urgently reversed. Despite proven efficacy in developed countries, newborn screening programs are not universal in SSA. This calls for a consolidated effort to make this possible, through the use of rapid, accurate, and cheap point-of-care test kits which require minimal training. For almost two decades, hydroxyurea (hydroxycarbamide), a century-old drug, was the only disease-modifying therapy approved by the U.S. Food and Drug Administration. Recently, the list expanded to L-glutamine, crizanlizumab, and voxelotor, with several promising novel therapies in the pipeline. Despite its several limitations, hematopoietic stem cell transplant (HSCT) remains the only curative intervention for SCD. Meanwhile, recent advances in gene therapy trials offer a glimpse of hope for the near future, although its use maybe limited to developed countries for several decades.

Drug Repositioning: Antimalarial Activities of GABA Analogs in Mice Infected with Plasmodium berghei

BACKGROUND

Drug repositioning is becoming popular due to the development of resistance to almost all the recommended antimalarials. Pregabalin and gabapentin are chemical analogs of gamma- aminobutyric acid (GABA) approved for the treatment of epilepsy and neuropathic pain.

OBJECTIVE

This study investigates acute toxicities and antimalarial activities of pregabalin and gabapentin in the murine malarial model.

METHODS

Acute toxicities were assessed using the method of Lorke, while curative activities were assessed by the administration of serial doses of pregabalin and gabapentin to Plasmodium berghei infected mice. Pregabalin was further investigated for its prophylactic activity, and curative potential when combined with either artesunate or amodiaquine. All drugs were freshly prepared and administered orally. Thin films were collected, stained, and observed under the microscope for the estimation of parasitemia and calculation of percentage chemoinhibition or chemoprevention. In pregabalin -artesunate or -amodiaquine combination aspect of this study, survival day post-infection (SDPI) was recorded, while parasitemia was re-estimated for animals that survived till day 28.

RESULTS

The oral LD50 of gabapentin, as well as pregabalin, was >5,000 mg/kg. Gabapentin at 100 and 200 mg/Kg demonstrated 35.64% and -12.78% chemoinhibition, respectively, while pregabalin demonstrated 75.60% and 100.00% chemoinhibition at doses of 12.5 and 25 mg/Kg, respectively. Moreover, pregabalin at individual doses of 25, 50 mg/Kg, and in combination with either artesunate or amodiaquine demonstrated 100.00% chemoinhibition. In its prophylactic study, pregabalin was found to be 100% chemopreventive at individual doses of 12.5 and 25 mg/Kg.

CONCLUSION

Both GABA analogs have antimalarial properties, but pregabalin proved to be more efficacious.

Evidence-based interventions implemented in low-and middle-income countries for sickle cell disease management: A systematic review of randomized controlled trials

BACKGROUND

Despite ~90% of sickle cell disease (SCD) occurring in low-and middle-income countries (LMICs), the vast majority of people are not receiving evidence-based interventions (EBIs) to reduce SCD-related adverse outcomes and mortality, and data on implementation research outcomes (IROs) and SCD is limited. This study aims to synthesize available data on EBIs for SCD and assess IROs.

METHODS

We conducted a systematic review of RCTs reporting on EBIs for SCD management implemented in LMICs. We identified articles from PubMed/Medline, Global Health, PubMed Central, Embase, Web of Science medical subject heading (MeSH and Emtree) and keywords, published from inception through February 23, 2020, and conducted an updated search through December 24, 2020. We provide intervention characteristics for each study, EBI impact on SCD, and evidence of reporting on IROs.

MAIN RESULTS

29 RCTs were analyzed. EBIs identified included disease modifying agents, supportive care agents/analgesics, anti-malarials, systemic treatments, patient/ provider education, and nutritional supplements. Studies using disease modifying agents, nutritional supplements, and anti-malarials reported improvements in pain crisis, hospitalization, children's growth and reduction in severity and prevalence of malaria. Two studies reported on the sustainability of supplementary arginine, citrulline, and daily chloroquine and hydroxyurea for SCD patients. Only 13 studies (44.8%) provided descriptions that captured at least three of the eight IROs. There was limited reporting of acceptability, feasibility, fidelity, cost and sustainability.

CONCLUSION

EBIs are effective for SCD management in LMICs; however, measurement of IROs is scarce. Future research should focus on penetration of EBIs to inform evidence-based practice and sustainability in the context of LMICs.

CLINICAL TRIAL REGISTRATION

This review is registered in PROSPERO #CRD42020167289.

Sickle cell disease and malaria: decreased exposure and asplenia can modulate the risk from Plasmodium falciparum

Background

Patients with sickle cell disease (SCD), an inherited haemoglobinopathy, have increased risk of malaria, at least in part due to impaired splenic function. Infection with Plasmodium falciparum in SCD patients can trigger painful vaso-occlusive crisis, increase the severity of anaemia, and contribute to early childhood mortality.

Case presentation

A 17 year-old Tanzanian male with known SCD was admitted to Muhimbili National Hospital, a tertiary referral centre in Dar-es-Salaam, following an attack of malaria. From 2004 to 2007 the patient had lived in USA, and from 2010 to 2016 in France where, on account of hypersplenism and episodes of splenic sequestrations, in 2014 the spleen was removed. After appropriate clinical and laboratory assessment the patient was re-started on hydroxyurea; and anti-malarial-prophylaxis with proguanil was instituted. The patient has remained well and malaria-free for the following 15 months.

Conclusion

SCD patients are highly vulnerable to malaria infection, and impaired splenic function is a feature of SCD patients, even in those who still anatomically have a spleen. This patient had a surgical splenectomy and, in addition, had probably lost some of the acquired malaria-immunity by having lived for several years in malaria-free areas. This patient is a compelling reminder that long-term anti-malarial prophylaxis should be offered to all patients with SCD who live in malaria-endemic areas.

Utilization patterns of malaria chemoprophylaxis among Tanzanian children attending sickle cell clinic in Dar es Salaam tertiary hospitals

BACKGROUND

Malaria is among the leading cause of infection in individuals with sickle cell disease (SCD) living in sub-Saharan Africa, including Tanzania. However, after 2005 the standard treatment guidelines (STGs) on malaria chemoprevention for SCD patients were non-existent, and at present no medicine is recommended for SCD patients. Since several anti-malarials have been approved for the treatment of malaria in Tanzania, it is important to establish if there is a continued use of chemoprevention against malaria among SCD children.

METHODS

A cross-sectional, hospital-based study was conducted between January and June 2019 at tertiary hospitals in Dar es Salaam. Data were collected using a semi-questionnaire and analysed using SPSS software version 25. The descriptive statistics were summarized using proportions, while factors associated with the use of chemoprophylaxis were analysed using multivariate logistic regression. Statistical significance of p < 0.05 was accepted.

RESULTS

A total of 270 SCD children were involved. The median age of SCD children was 6 years (interquartile range (IQR): 3-11 years). Of 270 SCD children, 77% (number (n) = 218) of children with SCD had not been diagnosed with malaria in the previous year, whereas 12.6% (n = 34) of children were admitted because of malaria in the previous year. Regarding the use of chemoprophylaxis in SCD children, 32.6% (n = 88) of parents were aware that, chemoprophylaxis against malaria is recommended in SCD children. Of the 270 participants, 17% (n = 46) were using malaria chemoprophylaxis. A majority used artemisinin combination therapy (ACT), 56.8% (n = 26). Of 223 parents who did not give chemoprophylaxis, the majority (n = 142, 63.7%) indicated unavailability at clinics as the reason. Children whose parents were primary level educated were 9.9 times more likely to not use chemoprophylaxis (adjusted odds ratio (AOR); 9.9, 95% CI 1.8-56.5, P = 0.01) compared to those whose parents had tertiary education.

CONCLUSION

Despite the lack of STGs, a small proportion of children with SCD were using malaria chemoprophylaxis where the majority used ACT, i.e., dihydroartemisinin-piperaquine.

Safety and effectiveness of antimalarial therapy in sickle cell disease: a systematic review and network meta-analysis

BACKGROUND

About 80% of all reported sickle cell disease (SCD) cases in children anually are recorded in Africa. Although malaria is considered a major cause of death in SCD children, there is limited data on the safety and effectiveness of the available antimalarial drugs used for prophylaxis. Also, previous systematic reviews have not provided quantitative measures of preventive effectiveness. The purpose of this research was to conduct a systematic review and meta-analysis of the available literature to determine the safety and effectiveness of antimalarial chemoprophylaxis used in SCD patients.

METHODS

We searched in PubMed, Medline, CINAHL, POPLine and Cochrane library, for the period spanning January 1990 to April 2018. We considered randomized or quasi-randomized controlled trials comparing any antimalarial chemoprophylaxis to, 1) other antimalarial chemoprophylaxis, 2) placebo or 3) no intervention, in SCD patients. Studies comparing at least two treatment arms, for a minimum duration of three months, with no restriction on the number of patients per arm were reviewed. The data were extracted and expressed as odds ratios. Direct pairwise comparisons were performed using fixed effect models and the heterogeneity assessed using the I-square.

RESULTS

Six qualified studies that highlighted the importance of antimalarial chemoprophylaxis in SCD children were identified. In total, seven different interventions (Chloroquine, Mefloquine, Mefloquine artesunate, Proguanil, Pyrimethamine, Sulfadoxine-pyrimethamine, Sulfadoxine-pyrimethamine amodiaquine) were evaluated in 912 children with SCD. Overall, the meta-analysis showed that antimalarial chemoprophylaxis provided protection against parasitemia and clinical malaria episodes in children with SCD. Nevertheless, the risk of hospitalization (OR = 0.72, 95% CI = 0.267-1.959; I2 = 0.0%), blood transfusion (OR = 0.83, 95% CI = 0.542-1.280; I2 = 29.733%), vaso-occlusive crisis (OR = 19, 95% CI = 1.713-2.792; I2 = 93.637%), and mortality (OR = 0.511, 95% CI = 0.189-1.384; I2 = 0.0%) did not differ between the intervention and placebo groups.

CONCLUSION

The data shows that antimalarial prophylaxis reduces the incidence of clinical malaria in children with SCD. However, there was no difference between the occurrence of adverse events in children who received placebo and those who received prophylaxis. This creates an urgent need to assess the efficacy of new antimalarial drug regimens as potential prophylactic agents in SCD patients.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO (CRD42016052514).

Sickle Cell Disease Clinical Trials and Phenotypes

Sickle cell disease, one of the world’s most common genetic disorders is prevalent in sub-Saharan Africa. The trans-Atlantic slave trade accounted for the gene movement from Africa to the Caribbean and United States of America and lately, migration has resulted in the introduction of the gene to the United Kingdom and other parts of Europe. Different haplotypes exist, however the differences in these haplotypes are not sufficient to explain the different clinical variations within the same region or different settings.

Secondhand Smoke Is an Important Modifiable Risk Factor in Sickle Cell Disease: A Review of the Current Literature and Areas for Future Research

Sickle cell disease (SCD) is an autosomal recessive hemoglobinopathy that causes significant morbidity and mortality related to chronic hemolytic anemia, vaso-occlusion, and resultant end-organ damage. Tobacco smoke exposure (TSE) through secondhand smoke exposure in people with SCD of all ages and through primary smoking in adolescents and adults is associated with significantly increased morbidity, with increased rates of emergency department visits and hospitalizations for painful vaso-occlusive crises and acute chest syndrome (ACS). Secondhand smoke is also associated with pulmonary function abnormalities in children with SCD who are already at risk for pulmonary function abnormalities on the basis of SCD. TSE is emerging as one of the few modifiable risk factors of SCD. This review discusses the current state of the evidence with respect to TSE and SCD morbidity, discusses potential mechanisms, and highlights current gaps in the evidence and future research directions.

Preventing Infections in Sickle Cell Disease: The Unfinished Business

While encapsulated bacterial agents, particularly Streptococcus pneumoniae, are recognized as important microbes that are associated with serious illness in hosts with sickle cell disease (SCD), multiple pathogens are implicated in infectious manifestations of SCD. Variations in clinical practice have been an obstacle to the universal implementation of infection preventive management through active, targeted vaccination of these individuals and routine usage of antibiotic prophylaxis. Paradoxically, in low-income settings, there is evidence that SCD also increases the risk for several other infections that warrant additional infection preventive measures. The infection preventive care among patients with SCD in developed countries does not easily translate to the adoption of these recommendations globally, which must take into account the local epidemiology of infections, available vaccines and population-specific vaccine efficacy, environment, health care behaviors, and cultural beliefs, as these are all factors that play a complex role in the manifestation of SCD and the prevention of infectious disease morbidity.

Sickle cell disease

INTRODUCTION

Sickle cell disease causes chronic haemolytic anaemia, dactylitis, and painful acute crises. It also increases the risk of stroke, organ damage, bacterial infections, and complications of blood transfusion. In sub-Saharan Africa, up to one third of adults are carriers of the defective sickle cell gene, and 1% to 2% of babies are born with the disease.

METHODS AND OUTCOMES

We conducted a systematic overview, aiming to answer the following clinical question: What are the effects of pharmaceutical interventions to prevent sickle cell crisis and other acute complications in people with sickle cell disease? We searched: Medline, Embase, The Cochrane Library, and other important databases up to January 2015 (Clinical Evidence overviews are updated periodically; please check our website for the most up-to-date version of this overview).

RESULTS

At this update, searching of electronic databases retrieved 369 studies. After deduplication and removal of conference abstracts, 136 records were screened for inclusion in the overview. Appraisal of titles and abstracts led to the exclusion of 99 studies and the further review of 37 full publications. Of the 37 full articles evaluated, three already included systematic reviews were updated, two systematic reviews, two RCTs, and one subsequent RCT were added at this update. We performed a GRADE evaluation for 12 PICO combinations.

CONCLUSIONS

In this systematic overview, we categorised the efficacy for five interventions based on information about the effectiveness and safety of antibiotic prophylaxis in children aged under 5 years, antibiotic prophylaxis in children aged 5 years or older, hydroxyurea, malaria chemoprophylaxis, and pneumococcal vaccines.