Schistosomiasis is a tropical ailment caused by parasitic flatworms called schistosomes.
The company obtained the licence for the vaccine from the Texas Tech University Health Sciences Center in the US.
The first trial participant received the SchistoShield vaccine at the study site, Kaiser Permanente Washington Health Research Institute (KPWHRI).
Sponsored by the US National Institutes of Health unit National Institute of Allergy and Infectious Diseases, the open-label, dose-escalation trial will assess the safety and the immunogenicity of the vaccine in 45 healthy adult subjects aged between 18 and 55 years.
Five treatment arms, each enrolling nine participants, will be given three intramuscular doses of the vaccine at varying doses.
Furthermore, one group will be given the vaccine without an adjuvant while four other groups will receive it with an adjuvant to boost immune responses.
The company anticipates concluding the trial in April 2024.
Subsequent to Phase I trials in the US and Phase Ib trials in Madagascar and Burkina Faso, the company plans to launch vaccine efficacy trials in schistosome human challenge models in the Netherlands and Uganda next year.
Pai Life Sciences vice-president Sean Gray said: “Schistosomiasis is one of the deadliest tropical diseases in the world and is second only to malaria among parasitic diseases with the greatest devastating economic impact.
“Developing an effective vaccine against schistosomiasis has been elusive, and while many vaccine candidates have been tested, few have offered any significant protection.”