Research Roundup: Preventive antibodies for malaria, injectable PrEP, and an intranasal COVID-19 vaccine
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In a small study, nine people who received lab-made monoclonal antibodies were deliberately exposed to mosquitoes carrying the parasite that causes malaria—and did not become infected. In comparison, five of six people in the untreated control group developed the disease. The monoclonal antibody works by binding to a small portion of the circumsporozoite protein that studs the surface of the sporelike stage of the Plasmodium falciparum organism. While the trial was too small to confirm efficacy of the antibodies as a preventive method, the study will act as a proof of principle and open a new avenue for malaria prevention. The research team is now developing a new monoclonal antibody that is two to three times as potent, which it intends to test next year in a clinical trial in Mali.
A single injection of pre-exposure prophylaxis—or PrEP, used as an HIV prevention method—once every two months lowered HIV risk by 66 percent more than a daily pill, according to results from a three-year, real-world study. The study tested a single 600 milligram shot of cabotegravir, a long-acting antiretroviral cocktail, against Truvada, a daily oral antiretroviral drug regimen, among more than 4,500 patients. The difference in effectiveness was primarily a result of adherence, according to the research team—the PrEP shot guaranteed two months of protective medicine, while the pill regimen relies on maintaining a strict daily schedule. The bimonthly cabotegravir injection is currently under review by the US Food and Drug Administration, with a decision expected in late 2021 or early 2022.
On Friday, Bharat Biotech’s intranasal COVID-19 vaccine received regulatory approval in India to begin phase 2/3 trials after the nasal spray was well-tolerated in a phase 1 trial of volunteers aged 18 to 60. The adenoviral intranasal vaccine was safe, immunogenic, and well-tolerated in the preclinical toxicity studies and was able to elicit high levels of neutralizing antibodies in animal studies. The vaccine, known as BBV154, is the first nasal spray COVID-19 vaccine to undergo human trials in India. Bharat Biotech’s injectable COVID-19 vaccine, Covaxin, is already authorized for emergency use in India after demonstrating 77.8 percent efficacy against symptomatic COVID-19 and 93.4 percent efficacy against severe illness during its phase 3 clinical trials.