A group of scientists have developed an injectable HIV drug that blocks the virus from entering cells over a longer term. The drug has been tested on non-human primates, and if proven successful could replace so-called cocktail therapies currently in use.

University of Utah health scientists led the study in collaboration with researchers from the American National Institute of Allergy and Infectious Diseases, Beth Israel Deaconess Medical Center in Boston, and pharmaceutical company Navigen.

“This is an exciting new HIV therapeutic option for both prevention and treatment, with a unique mechanism of action compared to other approved drugs,” says Professor Michael  Kay, of the University  of Utah. The treatment could help those struggling with drug resistance, he adds.

Longer lasting peptides

“We think this drug could be used by itself to prevent HIV infection because initial HIV exposure typically involves a relatively small amount of virus,” Kay says. “This study showed that the vast majority of circulating HIV strains from around the world are potently blocked by CPT31.”

The researchers tested a unique drug called CPT31, based on a D-peptide that targets a critical pocket on HIV’s fusion machinery that rarely mutates. D-peptides are mirror images of naturally occurring peptides that have therapeutic properties. They are not degraded in the body and last much longer than natural peptides. This makes CPT31 especially suitable for a long-acting injectable formulation.

“In addition to their durability in the body, D-peptides are largely ignored by the immune system, preventing immune reactions that are a side effect often seen with traditional peptide and protein drugs,” says Brett Welch, senior director of technology and strategy at Navigen. The Utah-based company is managing the clinical trials.

“As a D-peptide, our hope is that CPT31 will provide extended viral suppression with a lower dose and reduced side effects,” says Welch.

Human trials

The drug’s is potentially a new option in the treatment and prevention of HIV treatment. Still, it is much too early in the research process to know exactly how it might fit into that treatment, adds Mitchell Warren, who is the executive director of the Aids Vaccine Advocacy Coalition (Avac). The drug still has to enter human clinical trials, which will take several years.

“This drug, along with dozens of others being looked at in laboratory and animal studies, shows some promise and it’s encouraging to see the researchers note the success they have seen in this early stage research,” he says, speaking to Health-e News.

One injectable ARV – cabotegravir or CAB-LA, given every two months as part of the HPTN 083 study – has shown effective prevention in Cisgender Men who have sex with men (MSM) and Transgender Women who have sex with men.

Different treatment options

An ongoing HPTN 084 long injectable treatment study among cisgender women in east and Southern Africa is set to bear results in a year. The drug’s developer, ViiV, is preparing to submit it for regulatory review.

New drugs, if successful, can give HIV positive people who develop drug resistance more treatment options.

“Another benefit for some people of an injectable drug that it is given monthly or even every two or three 3 months, so that people may be able to adhere to the drug regimen better. For some people a daily pill is easy to take, for others an injectable may be preferable,” Warren adds.

He points to the monthly dapivirine vaginal ring, which could offer this ease. HIV advocates hope authorities will soon approve it for use in east and southern African countries.

“The bottom line for HIV prevention is people have different needs and desires that should be met with a range of options so they can find what works for them.”