A new clinical trial reveals promising results on a monthly HIV shot that could someday replace the current daily regimen of pills.

A daily regimen of pills for those living with HIV may soon be a thing of the past.

A clinical trial published in the Lancet showed a new injectable antiretroviral therapy (ART) given every four or eight weeks may be just as effective as the daily oral medications that are currently used to keep the virus under control.

The current treatment for people living with HIV involves a lifelong, daily schedule of oral medication.

Maintaining the strict regimen is a struggle for some people, and low compliance can cause treatment failure and a rise in drug-resistant mutations.

The authors of the study hope the long-lasting ART could revolutionise HIV treatment.

“Adherence to medication remains an important challenge in HIV treatment. Long-acting injectable ART could provide some patients with a more convenient approach to manage HIV infection that avoids daily oral dosing, and the need to keep, store, and transport medications as they go about their daily lives,” Dr. David Margolis, an author of the study, said in a press release.

The trial took place at 50 sites in the United States, Canada, Germany, Spain, and France.

During the study, 309 participants were first put on daily oral medication for 20 weeks.

Once they had achieved viral suppression, some of the study participants were then given the injectable ART as a form of maintenance therapy either every four weeks or every eight weeks for a 96-week period.

At the end of the trial, viral suppression was maintained in 94 percent of participants who were given the injectable ART every eight weeks, compared with 87 percent in the four-week group.

Of the patients who were given oral medication throughout the 96-week period, 84 percent maintained viral suppression.

Researchers say the results are promising and further trials will take place.

“The introduction of single-tablet medication represented a leap forward in ART dosing, and long-acting antiretroviral injections may represent the next revolution in HIV therapy by providing an option that circumvents the burden of daily dosing. The results through to 96 weeks with this two-drug regimen are encouraging, and we now need further research, including the ongoing phase 3 trial, to confirm these findings,” Margolis said.

Slightly more than 1 million people in the United States are infected with HIV. Of those, 1 in 7 don’t know they’re infected.

This latest study represents another potential advancement in a long evolution of medication options.

“The evolution of treatment for HIV since the discovery of the virus has seen the development of single agents, then multiple agents that sometimes needed to be taken every four hours, to the development of single pills that could be taken once daily. The development of injectables that might need to be administered only every four or eight weeks, or perhaps even longer with further developments, represents an evolution in treatment that aims to make taking antiretroviral therapy more convenient and therefore more likely,” Rowena Johnston, PhD, vice president and director of research at the Foundation for AIDS Research (amfAR), told Healthline.

“We know that adherence to pill taking, whether for HIV treatment or prevention, or for blood pressure and diabetes medications, or for contraception, is difficult for some people,” Mitchell Warren, executive director of the AIDS Vaccine Advocacy Coalition (AVAC), told Healthline.

“We know that simplified regimens like once-daily pills, and potentially this periodic injection, can help many people stick to their treatment or prevention better. That means better health for them, and when the HIV in their system becomes undetectable it means they can’t pass on HIV to their sexual partners,” he added.

Low adherence to HIV medication can have severe consequences.

Failing to adhere to the regimen of medication can make someone with HIV more susceptible to other infections. It can also allow the virus in their system to mutate and become resistant to the drugs they’re prescribed.

This means a person may need to move on to second- and third-line therapies that are more difficult to adhere to and are often also more expensive.

A long-lasting injectable ART may assist in improving compliance for some people. But Warren points out that currently, healthy people living with HIV may get two to six months of their medication from a pharmacy at one time.

As such, a monthly or two monthly injection may actually require more visits to a healthcare provider than an oral medicine would.

However, he says, having more options is a positive step forward.

“Any treatment regimen, whether a daily pill or an injection every two months, has an adherence component. A periodic injection will work well for some people and not for others. The bottom line is we need more options that meet the needs of more people,” he said.