A long-acting and injectable implant is showing promise to prevent and treat HIV, according to a study with mice.
Rather than receiving a once-daily pill, patients can receive a continuous formulation of an antiretroviral medication called dolutegravir for nine months and then the implant can be removed. The drug, which was approved for use in the United States in 2013, is sold under the brand name Tivicay.
Researchers from the University of North Carolina School of Medicine and the Centers for Disease Control and Prevention published a new study Tuesday in the journal Nature Communications.
"Adherence to medications is essential for treatment success," Dr. J. Victor Garcia, a researcher at UNC, said in a press release. "This is clearly important for HIV/AIDS treatment and prevention but also for the treatment of many other chronic conditions like mental illnesses, hypertension and diabetes where this technology might have applications."
The researchers noted adherence to a once-daily regimen can be difficult for some people.
Sustained drug release has successfully improved adherence in patients with schizophrenia and as contraceptives.
"Our study found that the formulation delivered the drug effectively, and the implants were well tolerated with little or no sign of toxicity, for five months," said Dr. Martina Kovarova, assistant professor of infectious diseases at UNC-Chapel Hill, and a member of the UNC Center for AIDS Research. "It seems to us to be the ideal drug formulation for the prevention and treatment of HIV and AIDS."
The injectable formulation includes a three-component mixture: an anti-HIV drug, a polymer and a solvent. The liquid solidifies into an implant once injected under the skin and as the polymer slowly degrades, the drug is released.
The implant can be quickly and safely removed with a small incision in the skin at the injection site, the researchers said. That includes with an adverse reaction or if a patient becomes pregnant.
Other long-acting injectables currently in clinical trials cannot be removed after they have been injected, according to the researchers.
"In the specific case of HIV prevention, the lack of adherence by clinical trial participants has served to highlight the urgent need for drug delivery systems capable of offering long-term protection from HIV infection," the researchers wrote.