Improving Personalised Care for People Living with HIV

Long-acting injectable treatments are changing how HIV is managed, offering an alternative to daily oral medication and the potential for improved quality of life for people living with HIV. While these therapies have been shown to be highly effective, clinicians have observed that drug levels can vary widely between individuals, even when the same dose is given. Understanding why this happens is critical to ensuring these treatments are safe, effective, and tailored to each patient’s needs.

In 2023, the RPH Research Foundation supported research aimed at addressing this challenge through our Seed Funding Grants program. Led by Dr Mina John, her project titled “Utilising drug concentration monitoring to improve personalisation of long-acting antiretroviral therapy in patients living with HIV”, set out to better understand the real-world factors influencing how long-acting HIV medications are absorbed in the body.

Although long-acting injectable antiretroviral therapy has demonstrated strong results in clinical trials, researchers have reported large differences in drug concentrations between patients. These variations can increase the risk of subtherapeutic drug levels, which may lead to poorer disease control, drug resistance, or transmission.

This study aimed to identify individual and injection-related factors that may contribute to this variability, with the longer-term goal of supporting more personalised HIV treatment through therapeutic drug monitoring and improved injection practices.

Dr John and her team followed HIV patients receiving long-acting injectable therapy at Royal Perth Hospital over a 16-week period. Blood samples were collected to measure drug concentrations, and ultrasound imaging was used to examine injection sites. This allowed them to determine whether injections were reaching the muscle as intended or being delivered into fatty tissue beneath the skin. By combining this data with advanced pharmacokinetic modelling, they were able to better understand how drug absorption differed between individuals.

The study revealed that nearly one in three injections did not reach the muscle as intended and were instead delivered into subcutaneous (fatty) tissue. This occurred more frequently in women and in individuals with greater thickness between the skin and muscle at the injection site. When injections were delivered into subcutaneous tissue, one of the HIV medications was absorbed more slowly. This slower absorption helps explain why some patients, particularly women, experience different drug levels despite receiving the same treatment.

These findings provide important real-world evidence that injection technique and individual anatomy can significantly influence how long-acting HIV treatments work. By identifying factors that contribute to drug variability, this research supports the development of more personalised treatment approaches and improved clinical practice.

Long-acting injectable treatments are changing how HIV is managed, offering an alternative to daily oral medication and the potential for improved quality of life for people living with HIV. While these therapies have been shown to be highly effective, clinicians have observed that drug levels can vary widely between individuals, even when the same dose is given. Understanding why this happens is critical to ensuring these treatments are safe, effective, and tailored to each patient’s needs.

In 2023, the RPH Research Foundation supported research aimed at addressing this challenge through our Seed Funding Grants program. Led by Dr Mina John, her project titled “Utilising drug concentration monitoring to improve personalisation of long-acting antiretroviral therapy in patients living with HIV”, set out to better understand the real-world factors influencing how long-acting HIV medications are absorbed in the body.

Although long-acting injectable antiretroviral therapy has demonstrated strong results in clinical trials, researchers have reported large differences in drug concentrations between patients. These variations can increase the risk of subtherapeutic drug levels, which may lead to poorer disease control, drug resistance, or transmission.

This study aimed to identify individual and injection-related factors that may contribute to this variability, with the longer-term goal of supporting more personalised HIV treatment through therapeutic drug monitoring and improved injection practices.

Dr John and her team followed HIV patients receiving long-acting injectable therapy at Royal Perth Hospital over a 16-week period. Blood samples were collected to measure drug concentrations, and ultrasound imaging was used to examine injection sites. This allowed them to determine whether injections were reaching the muscle as intended or being delivered into fatty tissue beneath the skin. By combining this data with advanced pharmacokinetic modelling, they were able to better understand how drug absorption differed between individuals.

The study revealed that nearly one in three injections did not reach the muscle as intended and were instead delivered into subcutaneous (fatty) tissue. This occurred more frequently in women and in individuals with greater thickness between the skin and muscle at the injection site. When injections were delivered into subcutaneous tissue, one of the HIV medications was absorbed more slowly. This slower absorption helps explain why some patients, particularly women, experience different drug levels despite receiving the same treatment.

These findings provide important real-world evidence that injection technique and individual anatomy can significantly influence how long-acting HIV treatments work. By identifying factors that contribute to drug variability, this research supports the development of more personalised treatment approaches and improved clinical practice.