Researchers at Massachusetts Institute of Technology (MIT) and at Brigham and Women’s Hospital (BWH) have developed a capsule that can deliver a week’s worth of HIV treatment medication in a single dose.
A weekly treatment programme could make it much easier for patients to comply with the strict schedule of dosing required for the antiretrovirals to effectively fight the virus, the researchers say.
According to Science News, although the overall mortality rate of HIV has declined significantly since the introduction of antiretroviral treatment in the 1990s, there were 2.1 million new HIV infections and 1.2 million HIV-related deaths in 2015.
“One of the main barriers to treating and preventing HIV is adherence,” says Giovanni Traverso, a research affiliate at MIT’s Koch Institute for Integrative Cancer Research and a gastroenterologist and biomedical engineer at Brigham and Women’s Hospital. “The ability to make doses less frequent stands to improve adherence and make a significant impact at the patient level.”
The MIT/BWH team has developed the capsule based on a previous study by researchers using a similar capsule to gradually release the malaria drug ivermectin.
The capsule consists of a star-shaped structure with six arms that can be loaded with medication, folded inward, and encased in a smooth coating. After the capsule is swallowed, the arms unfold and gradually release their load.
In their original version, the entire star shape was made from one polymer that both provides structural support and carries the medicines. This made it more difficult to design new capsules that would release each medicine at varying rates, because any changes to the polymer composition might disrupt the capsule’s structural integrity.
To overcome that, the researchers designed a new version in which the backbone of the star structure is still a strong polymer, but each of the six arms can be filled with a different medicine-filled polymer. This makes it easier to design a capsule that releases medicines at different rates.
“In a way, it’s like putting a pillbox in a capsule. Now you have chambers for every day of the week on a single capsule,” Traverso says.
Preventing HIV infection
Working with the Institute for Disease Modeling in Bellevue, Washington, the researchers tried to predict how much impact a weekly dose of antiretrovirals could have on preventing HIV infections. They calculated that going from a daily dose to a weekly dose could improve the efficacy of HIV preventative treatment by about 20 percent. When this figure was incorporated into a computer model of HIV transmission in South Africa, the model showed that 200 000 to 800 000 new infections could be prevented over the next 20 years.
“A longer-acting, less invasive oral formulation could be one important part of our future arsenal to stop the HIV/AIDS pandemic,” says Anthony Fauci, director of the National Institute of Allergy and Infectious Disease, which partly funded the research.
The research was also funded by the Bill and Melinda Gates Foundation, Bill and Melinda Gates through the Global Good Fund, the National Institutes of Health, and the Division of Gastroenterology at Brigham and Women’s Hospital.