Preferences of Patients and Providers in High-Burden Malaria Settings for Long-Acting Malaria Chemoprevention.

Antimalarial medications are recommended for chemoprevention as part of malaria control programs to decrease the morbidity and mortality related to more than 200 million infections each year. We sought to evaluate patient and provider acceptability of malaria chemoprevention in a long-acting formulation. We administered questionnaires to patients and providers in malaria endemic districts in Kenya and Zambia. Questions explored preferences and concerns around long-acting antimalarial formulations compared with oral formulations. We recruited 202 patient respondents (Kenya, n = 102; Zambia, n = 100) and 215 provider respondents (Kenya, n = 105; Zambia, n = 110). Long-acting injection was preferred to oral pills, whereas oral pills were preferred to implant or transdermal administration by patient respondents. Of 202 patient respondents, 80% indicated that they 'definitely would try' malaria chemoprevention offered by injection instead of oral pills. Of parents or guardians, 84% of 113 responded that they 'definitely would' have their child age < 12 years and 90% of 88 'definitely would' have their child ≥12 years receive an injection for malaria prevention. Provider respondents indicated that they would be more likely to prescribe a long-acting injectable product compared with an oral product for malaria chemoprevention in adults (70%), adolescents ages 12 years and older (67%), and children <12 years (81%). Potential for prolonged adverse effects with long-acting products was the highest concern for patient respondents, while higher medication-related cost was cited as the most concerning barrier to implementation by providers. Overall, these findings indicate enthusiasm for the development of long-acting injectable antimalarials to provide individual delivery method options across age groups.

Long-acting injectable atovaquone nanomedicines for malaria prophylaxis.

Chemoprophylaxis is currently the best available prevention from malaria, but its efficacy is compromised by non-adherence to medication. Here we develop a long-acting injectable formulation of atovaquone solid drug nanoparticles that confers long-lived prophylaxis against Plasmodium berghei ANKA malaria in C57BL/6 mice. Protection is obtained at plasma concentrations above 200 ng ml-1 and is causal, attributable to drug activity against liver stage parasites. Parasites that appear after subtherapeutic doses remain atovaquone-sensitive. Pharmacokinetic-pharmacodynamic analysis indicates protection can translate to humans at clinically achievable and safe drug concentrations, potentially offering protection for at least 1 month after a single administration. These findings support the use of long-acting injectable formulations as a new approach for malaria prophylaxis in travellers and for malaria control in the field.

The Relative Effects of Artemether-lumefantrine and Non-artemisinin Antimalarials on Gametocyte Carriage and Transmission of Plasmodium falciparum: A Systematic Review and Meta-analysis.

BACKGROUND: Artemisinin-based combination therapies (ACTs) have been widely adopted as first-line agents to treat uncomplicated falciparum malaria due to their activity against multidrug resistant parasites. ACTs may also disrupt transmission through a direct antigametocyte effect, but the extent of this effect is uncertain. We assessed the evidence for and estimated the effects of the most widely-deployed ACT, artemether-lumefantrine (AL), relative to non-ACTs on gametocyte clearance and transmission interruption. METHODS: We searched electronic databases for randomized controlled trials comparing AL to non-ACTs that reported gametocyte counts or results of mosquito-feeding assays. Two authors working independently assessed eligibility, extracted data, and evaluated the risk of bias. We conducted meta-analyses using a random-effects model. RESULTS: We identified 22 eligible trials. The pooled odds of gametocytemia at 1 week were lower in AL- compared to non-ACT-treated participants (odds ratio [OR] 0.09; 95% confidence interval [CI], 0.06-0.15; I2 = 0.60, P < .01; 15 trials). The odds of transmission to mosquitoes were also lower in AL treatment groups (OR 0.06; 95% CI, 0.00-0.47, P < .01 at 7 days post-treatment; 1 trial; OR 0.56; 95% CI, 0.36-0.88, P = .01 at 14 days post-treatment; 1 trial). CONCLUSION: AL is superior to non-ACTs in reducing gametocytemia, and, based on limited evidence, abating transmission to mosquitoes. The transmission-limiting benefit of AL has relevance for policymakers planning optimal utilization of control strategies, including use of ACTs for malaria treatment and chemoprevention.