A Cambridge nonprofit is developing an inhaled form of the tuberculosis vaccine for the developing world.

Pamela Ferdinand

Nearly two million people around the world die of tuberculosis each year, most of whom live in the developing world. A vaccine exists but is difficult to distribute and administer in countries lacking an advanced health care system. A Cambridge-based nonprofit, Medicine in Need (MEND), led by Harvard University bioengineering professor David Edwards, aims to change that.

Edwards has developed a new method of vaccination using a powdered, inhalable form of the TB vaccine. Patients could essentially vaccinate themselves using a simple handheld inhaler instead of relying on trained personnel to give needle injections. And the powdered form would not require refrigeration, in contrast to the current Bacillus Calmette-Guerin, or BCG, vaccine.

“The idea of having a new approach that broadens therapy and increases the likelihood of success is important,” Edwards says.

Not for profit

Rather than struggle to find investors for a company devoted to problems of the developing world, Edwards decided to create a nonprofit in 2003 with colleagues and students to bring technology from his lab into the field. Harvard licensed Edward’s technology to MEND but has pledged to forego royalties earned from the technology in developing countries and a major share of royalties earned elsewhere.

MEND manages a $10 million grant that Edwards received in 2005 from the Bill and Melinda Gates Foundation and is working with the Aeras Global TB Vaccine Foundation to develop the new form of the BCG vaccine. It is also planning a manufacturing facility in Cape Town, South Africa, which aims to begin producing powdered forms of standard and recombinant BCG vaccine by late 2008.

To convert the BCG vaccine into an inhalable powder, Edwards and his colleagues developed a spray-drying method that does not kill the live bacterial cells in the vaccine but creates particles tiny enough to be inhaled.

In a paper published in February, the researchers showed that the spray-dried vaccine maintained its activity at room temperature for up to four months.

And preliminary animal data show that vaccination with aerosolized BCG is more protective than injections, likely because it’s delivered directly to the lungs, the main site of TB infection. Tests in humans could begin in late 2008, Edwards says.

Spray drug

MEND also plans to begin clinical testing of an inhalable form of the antibiotic capreomycin used to treat drug-resistant forms of the disease, which kills 500,000 people worldwide each year. Although effective, this drug is expensive, with treatment costing $3,000 per person and requiring daily injections and oral medications.

Sending powdered capreomycin directly into the lungs via an inhaler could reduce doses by up to 50 percent, potentially lowering the cost and lessening severe and painful side effects for patients, many of whom also have HIV, says Alexis Wallace, executive director of MEND.

The FDA last year approved inhaled insulin for diabetes, but sales have reportedly lagged due to questions about its safety, cost, and convenience. Whether an inhaled TB vaccine or antibiotic proves effective compared to existing treatments remains to be seen, but an aerosolized drug that achieves the desired effect would be “fantastic,” says Kenneth Castro, director of the U.S. Centers for Disease Control’s Division of Tuberculosis Elimination.

“The big question is, ‘Will a drug delivered by the lungs act better than [injected drugs]?” he says. “We would need to see evidence. The facts should speak for themselves.”