Researchers are testing a 'pillbox in a capsule' that can slowly release six different medications.
One of the more difficult challenges in fighting HIV is getting patients to consistently take their medicine. Combination therapies—which, as the name implies, use multiple drugs in conjunction—have shown success not just in managing the disease, but in preventing its spread. Unfortunately, they require strict dosage regimens, typically involving multiple pills a day; studies show that only about 30 percent of patients stick with their plans, which blunts their treatment.
To combat that problem, researchers at MIT and Brigham and Women's Hospital have developed a slow-release “mini pill box” that stays in the stomach and delivers a long-lasting dose of medications to combat HIV. It taken once a week and could help improve treatment for patients, but also could be given to people at high risk of HIV exposure to reduce their risk of infection, according to researchers. The study was published in Nature Communications and funded in part by the National Institutes of Health and the Bill and Melinda Gates Foundation.
"These slow-release dosage systems perform equal or better than the current daily doses for HIV treatment in preclinical models," Giovanni Traverso, a gastroenterologist and biomedical engineer at Brigham and Women's Hospital, said in a statement. (Preclinical meaning it hasn’t been tested in humans yet. More on that below.)
Antiretroviral therapies, which use a combination of drugs to slow the rate at which HIV multiplies in the body, have helped lower the overall mortality rate of the virus since their introduction in the 1990s. Yet according to UNAIDS, 1.8 million people were newly infected in 2016, and 1 million died from AIDS-related illnesses that year.
In June 2017, 20.9 million people were using antiretroviral therapy, and several large clinical trials have tested whether antiretroviral drugs can prevent infection among healthy people (in what’s known as pre-exposure prophylaxis, or PrEP). One stumbling block, though, is keeping patients on their daily pill regimen.
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The MIT-BWH team had developed a drug-delivery capsule in 2016 that they thought could address the problem. It’s small and star-shaped with six arms that can be loaded with different drugs, which are then folded in and covered in a smooth coating. When swallowed, the coating dissolves and the capsule remains in the stomach and the arms unfold, slowly dosing the patient while still allowing food to pas through the stomach.
"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 said. Well, almost every day of the week.
Researchers had previously shown the capsules could stay in the stomach for up to two weeks. They’d worked with a malaria drug and set out to see whether the same approach could work for HIV meds. By tweaking their design, they created a capsule that could release drugs at different rates.
They then tested the new “pillbox”—on pigs. The system delivered three antiretroviral drugs slowly over the course of a week, in doses high enough to be effective per blood tests. One caveat, though: This is an early feasibility study, showing that the capsule can deliver a prolonged dose of the drugs as planned. It doesn’t yet prove that this approach is safe in humans or will be as potent at treating HIV as today’s daily doses.
But there’s cause for optimism. The team applied mathematical models which show that a simplified treatment regimen could improve medication adherence rates for patients with HIV as well as help prevent new cases of HIV among high-risk people. That is, if it proves successful in humans. Researchers are now working on that, scaling up their development and looking to move down the long road from preclinical tests to treating actual patients. They're also working on adapting the technology for other diseases that could benefit from weekly dosing.
The pharmaceutical company developing the capsule is planning human trials of the pill within the next 12 months, according to the BBC, then tests of the capsule with HIV drugs after that.
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