TB prevention drugs do not weaken ARVs, Kenyans told

People starting HIV treatment can confidently take their ARVs alongside drugs to prevent tuberculosis as new evidence shows this is safe.

Results show there are minimal side effects and no adverse drug-drug reactions.

People with HIV are up to 50 times more likely to develop TB in a given year than HIV-negative people.

However, there were fears that drugs to prevent TB could weaken the ARVs.

The current trial evaluated how dolutegravir (DTG)-based ARVs work when taken together with 3HP, a three-month course of TB drugs isoniazid and rifapentine that prevents TB.

The Ministry of Health estimates that up to 38 per cent of Kenyans with tuberculosis (TB) are co-infected with HIV.

“This study looked at the safety, efficacy and drug levels of DTG when given together with 3HP from the outset in new HIV patients. Though an expected interaction was seen, DTG still held down HIV viral loads, and the combination was safe and well-tolerated,” said Dr Ethel Weld, the principal investigator in the study, in results presented at the 2024 Conference on Retroviruses and Opportunistic Infections in Colorado on Wednesday.  

DTG is the first line drug to treat HIV in Kenya.

Researchers in the trial-called “Dolphin-Too”-have been testing the drug-to-drug interactions in a three-month or six-month course to treat TB.

Studies have shown the 3HP tuberculosis prevention regimen is preferred by patients, has less toxicity and is more achievable for patients to complete than the longer courses of isoniazid (which can last up to a year in some places).

The trial focused on whether the levels of DTG in the blood were impacted by the 3HP regimen.

The results showed that people in the 3HP group did have lower levels the DTG in their blood stream than people in the six-month TB treatment group.

“They were nonetheless able to achieve viral suppression (an undetectable level of HIV virus in blood) by eight weeks and maintain it for the length of the six-month study,” researchers said.

They said that minimal side effects were seen, none were severe and the majority were resolved with continuation of treatment.

The results will inform WHO and country level policy on the timing of TB preventive treatment in people who are newly initiating DTG-based ART in high burden TB countries globally.

“For patients with HIV, the best time to start TB preventive treatment is when they are first starting ART,” said Prof Gavin Churchyard, the group CEO of the Aurum Institute.

“This is when patients are most closely monitored and are in regular contact with clinics and healthcare providers, making it easier to monitor them for any potential side effects.”

In 2022, donors announced a reduced cost of the T drugs, making them more accessible.

Under the initiative, 3HP, a three-month, once-weekly oral treatment for the treatment of latent TB infection is now available at a ceiling price of $14.25 (Sh1,500).

The cost was previously as high as $333 (Sh36,000).

According to data by Unitaid and WHO, in 2020 alone, more than 1.5 million people died from TB, while around 10 million people fell ill from the disease globally.

About one-quarter of the world’s population is infected with a latent form of TB that causes no symptoms and is not contagious.

Without treatment, five to 10 per cent of those infected will develop active TB, which causes severe illness and can be transmitted from person to person through the air.

TB prevention treatment regimens like 1HP and 3HP lower the risk of progression to TB in people at risk, including children, pregnant women and people living with HIV.