MV vaccine prevents TB in people with HIV infection

Results from clinical trials conducted in Tanzania show that a new vaccine against tuberculosis, Mycobacterium vaccae (MV), is effective in preventing tuberculosis in people with HIV infection. Findings from the trials, which were conducted by investigators from Dartmouth Medical School in the United States, will be published in the next issue of AIDS, the leading journal in the field of HIV and AIDS research. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health, a leading provider of information and business intelligence for students, professionals, and institutions in medicine, nursing, allied health, and pharmacy.

TB is the most common cause of death associated with HIV/Aids in developing countries, and the results of the Tanzanian trials are a "significant milestone," according to Principal Investigator Ford von Reyn, M.D., director of the DarDar International Programs for the Section on Infectious Disease and International Health at DMS.

"Since development of a new vaccine against tuberculosis is a major international health priority, especially for patients with HIV infection, we and our Tanzanian collaborators are very encouraged by the results," said von Reyn.

The Dartmouth group began Phase-I human studies with MV in the United States in 1994, in collaboration with Robert Arbeit, M.D., and demonstrated that a multiple-dose series of MV was safe in both healthy subjects and patients with HIV infection. The group then conducted Phase-II studies in larger groups of patients in Zambia and in Finland. In the Zambian trial, Richard Waddell, D.Sc., a research assistant professor at Dartmouth Medical School, found that MV boosted immune responses against tuberculosis. Subsequently, the Dartmouth group received funding from the National Institute of Health (NIH) to conduct the large Phase-III efficacy trial in Tanzania, under the direction of Lillian Mtei, M.D., in Dar es Salaam.

The DarDar Health Study, named for Dartmouth and Dar Es Salaam, Tanzania, found that MV immunization reduced the rate of definite tuberculosis by 39 percent among 2,000 HIV-infected patients in Tanzania. Since newly-infected HIV patients risk contracting TB almost immediately, Dartmouth investigators are targeting a strategy for administration of MV before patients need to start taking antiretroviral drugs.

Von Reyn suggests that the next steps are to improve the manufacturing methods to support the production of the larger quantities of the TB vaccine needed for further studies and subsequent clinical use. Development work on manufacturing is being conducted by the Aeras Global TB Vaccine Foundation in Rockville, Maryland, in conjunction with the London-based manufacturer, Immodulon Therapeutics.

"Aeras' goal is to speed the development and distribution of new TB vaccines for those who need them most," said Jerald C. Sadoff, MD President and Chief Executive Officer of Aeras Global TB Vaccine Foundation. "We are pleased that our internal manufacturing capacity can assist in the further development of this TB vaccine."

The vaccine is a type known as an inactivated whole cell mycobacterial vaccine and is expected to be economical to produce and distribute, von Reyn said.