US – The National Institute of Allergy and Infectious Diseases’ (NIAID) phase 1 clinical trials of its malaria vaccine, Sanaria (PfSPZ), have found that the regimen conferred unprecedentedly high levels of durable protection when volunteers were later exposed to disease-causing malaria parasites.
Trials were conducted at the National Institutes of Health (NIH) Clinical Centre in Bethesda, Maryland led by Patrick E. Duffy, M.D., of the NIH National Institute of Allergy and Infectious Diseases (NIAID), and Stephen L. Hoffman, M.D., CEO of Sanaria Inc., Rockville, Maryland.
In the CVac trials, healthy adult volunteers received PfSPZ along with either pyrimethamine, a drug that kills liver-stage parasites, or chloroquine, which kills blood-stage parasites.
Three months later, under carefully controlled conditions, the volunteers were exposed to either an African malaria parasite strain that was the same as that in the vaccine (homologous challenge) or a variant South American parasite (heterologous challenge) that was more genetically distant from the vaccine strain than hundreds of African parasites.
At the lowest PfSPZ dosage, the CVac approach conferred modest protection: only two of nine volunteers (22.2%) who received the pyrimethamine combination were protected from homologous challenge.
In contrast, seven out of eight volunteers (87.5%) who received the highest PfSPZ dosage combined with pyrimethamine were protected from homologous challenge, and seven out of nine volunteers (77.8%) were protected from heterologous challenge.
For case of the chloroquine combination, all six volunteers (100%) who received the higher PfSPZ dosage were completely protected from heterologous challenge.
The high levels of cross-strain protection lasted at least three months (the time elapsed between vaccination and challenge) for both higher-dose regimens.
One hundred percent protection for three months against heterologous variant parasites is unprecedented for any malaria vaccine in development according to the findings.
These data suggest that CVac could be a promising approach for vaccination of travellers and people living in malaria-endemic areas.
Phase 2 clinical trial of the vaccine is now underway in Mali, a malaria-endemic country and if the approach proves successful for the CVac, the malaria disease could be a thing of the past.
With the Global Malaria Vaccine Market expected to grow from US$ 32.58 Million in 2020 to US$ 98.47 Million by the end of 2025 according to Reporter Linker, companies are onboarding the vaccine bandwagon in a bid to find a solution against Malaria.
These companies include, Bharat Biotech International Limited, Cadila Healthcare Ltd., GlaxoSmithKline PLC, Novartis International AG, Novavax, Inc., Sun Pharmaceutical Industries Ltd., and VLP Therapeutics LLC.