Ohio State vaccine enters human trial path for leishmaniasis

Researchers at The Ohio State University are moving a first-ever leishmaniasis vaccine toward human testing after strong animal results and FDA clearance as an investigational new drug. The effort comes as the tropical parasite spreads beyond traditional regions and doctors see more U.S. cases.

Why it matters: - Leishmaniasis is becoming a greater U.S. health concern as infected sand flies are found in states bordering Mexico and more domestic cases are appearing. - The Ohio State University vaccine could become the first preventive shot for a disease that can cause skin damage, organ failure and death. - Better awareness could help physicians recognize unexplained skin sores and other symptoms sooner, especially in patients with travel, military or residence exposure in endemic regions.

What happened: - Ohio State researchers developed a first-ever vaccine candidate for leishmaniasis and are preparing to begin human trials later this year. - The vaccine showed 100% effectiveness in animal studies. - The U.S. Food and Drug Administration approved the vaccine last year as an investigational new drug. - Planned trial sites include Brazil and Kenya, with a U.S. site expected to be added. - Abhay Satoskar, a professor of pathology at Ohio State’s College of Medicine, helped create the vaccine.

The details: - Leishmaniasis is caused by parasites spread through the bite of an infected female sand fly. - The disease has long been associated with Africa, the Middle East and South America, but deforestation and climate change have helped make it endemic in parts of Europe and the U.S. - The World Health Organization lists leishmaniasis as one of the top neglected tropical diseases. - About 6 million people are infected at any given time, with up to 1 million new cases each year. - More than 1 billion people in 99 endemic territories and countries are at risk. - Satoskar said an effective vaccine is indispensable for eliminating the disease and noted that leishmaniasis is a new U.S. disease compared with earlier years of his career. - Earlier vaccine attempts used parasites that could spread in the body or included antibiotic-resistant genes, making them unsafe for human use. - Ohio State researchers used CRISPR gene-editing to remove the gene from the skin-only parasite species and create a safer vaccine that trains the immune system without causing disease. - Funding for the trial comes from Japan-based Global Health Innovative Technology Fund and the Wellcome Trust in the United Kingdom. - Ohio State researchers are also promoting a skin test they helped develop that is similar to a tuberculosis test and could help detect cases and track spread. - Bradford McGwire, an infectious diseases physician at Ohio State Wexner Medical Center, said U.S. cases have risen to about two to four a year at Ohio State over the last two years, compared with about one a year in the past.

Between the lines: - The vaccine effort reflects a shift from leishmaniasis being viewed mainly as a tropical-world problem to a disease that U.S. doctors may need to diagnose more often. - Clinical trial plans in Brazil and Kenya suggest researchers are targeting regions where the disease burden is high while also building evidence for use in the U.S. - The skin test may matter as much as the vaccine in the near term because diagnosis remains a barrier when clinicians do not suspect leishmaniasis. - McGwire also studies Chagas disease, another tropical parasitic illness that is rising in the U.S., reinforcing a broader trend of imported or expanding vector-borne disease.

What’s next: - Human trials are expected to begin later this year. - Satoskar is traveling to meet with the vaccine manufacturer, investors and leishmaniasis experts as the trial launch approaches. - Ohio State physicians and researchers plan to keep raising awareness about symptoms, testing and treatment as U.S. exposure risk grows.

The bottom line: - A successful trial could turn leishmaniasis from a growing tropical threat into a preventable disease, including in the U.S.