New leprosy vaccine purpose-built to prevent the disease enters human trials for the first time.

American Leprosy Missions and the Infectious Disease Research Institute (IDRI) announced the start of Phase I clinical trials to test the effectiveness of a promising new vaccine candidate specifically developed to fight leprosy, one of the oldest of all known diseases to afflict humans.

Also known as Hansen’s disease, records of leprosy afflicting humans have been dated to 600 BC and genetic evidence of the infection in human remains some 100,000 years old. Caused by the bacteria Mycobacterium leprae, IDRI said nearly a quarter-million people suffer from the disease, which the World Health Organization characterized as the “neglected tropical disease.”

According to IDRI, its scientists and institutions including the National Hansen's Disease Program, the National Institute of Allergy and Infectious Diseases (part of the National Institutes of Health) collaborated over 15 years to develop the leprosy vaccine candidate with $5.1 million in financial support from American Leprosy Missions donors.

Leprosy is a progressive, debilitating disease that causes irreversible nerve damage and disfigures mucus membranes and skin. A pharmaceutical therapy is available, but IDRI explained it has numerous side effects and is often administered too late to reverse the damage caused by the bacteria. A viable vaccine said IDRI, is the next step in stopping the disease permanently.

"While previous attempts have used vaccines primarily developed for other diseases, this is the first totally defined vaccine candidate developed specifically for leprosy, using the latest technologies and offering no less than those exposed to leprosy deserve," said Ph.D., IDRI President, CEO & Founder Steven Reed, "The leprosy vaccine program at IDRI has benefited greatly from what we've learned in the development of tuberculosis vaccine candidates over the past two decades.”

Reed pointed out that even though the bacteria that causes tuberculosis and leprosy are related, leprosy vaccine development poses greater hurdles. “This vaccine represents a unique accomplishment,” he said, “requiring the most advanced technologies in molecular biology and immunology, and American Leprosy Missions has been there from the beginning." IDRI scientists have also developed two vaccine candidates for tuberculosis, both in clinical stages of development.

Data generated in preclinical studies demonstrated the vaccine candidate LepVax was effective enough to progress to Phase I human clinical trials and evaluate the immune response to the vaccine.