5 days ago
New HIV Prevention Drug Holds Promise for Australia
Oral preexposure prophylaxis (PrEP) has played a significant role in Australia's reduction of new HIV infections, but experts have sounded the alarm over ongoing challenges. They suggested that new, long-acting injectables have a potential role in ending the epidemic.
In 2018, oral PrEP became available on the Pharmaceutical Benefits Scheme (PBS), which provides universal and inexpensive access to citizens and long-term residents. The scheme led to a drastic rise in the use of PrEP.
In 2023, the number of people who had taken PrEP in the previous 12 months increased from 6432 to 45,244. While most new HIV infections are among gay and bisexual men (GBM), diagnoses among this group have decreased by 43% in the past 10 years.
But general practitioners (GPs) and HIV researchers told Medscape Medical News that despite the great intervention, there were problems related to discontinuation. More than half of new infections occur among patients who were previously on PrEP.
A 2023 study found that of all patients who were dispensed subsidized PrEP in Australia, more than 40% had discontinued for more than 6 months. By 2 years after receiving their first PrEP supply, 37.7% of patients were no longer taking it.
Access and Discontinuation
'In my clinic, a significant proportion of new infections are among people who took PrEP in the past but stopped it for whatever reason,' Jason Ong, MBBS, PhD, director of Melbourne Sexual Health Centre and professor of medicine at Monash University, Melbourne, told Medscape Medical News .
Jason Ong, MBBS, PhD
'That's one of the downsides of oral PrEP: It's contingent on someone taking it appropriately. As good as it is, people get fatigued and don't want to take it anymore and then put themselves at risk.'
Benjamin Bavinton, PhD, associate professor of medicine and health at the University of New South Wales in Sydney and group leader of the Biobehavioural Prevention Research Group within the HIV Epidemiology and Prevention Program at the Kirby Institute in Kensington, agreed that discontinuation was an issue but said he wasn't surprised because research suggests that people come on and off PrEP throughout their lives.
'The question to ask is why this is happening. Why were they not able to get on PrEP before they engaged in the risky encounter? What were the barriers they faced in getting back on PrEP? Often, it's them not having enough sex to warrant them being on a daily pill,' he said.
But while some patients opt out of oral PrEP, others struggle to access it in the first place. 'There are certain populations who can't access PrEP easily: those who can't access Medicare, such as international students. These are overseas-born men who have sex with men, and we haven't seen the same [HIV] reductions in this group,' said Ong.
'If you can't access it easily, you're not going to use it properly. And because they can't access Medicare, even if they do want PrEP, they're often not getting the right culturally safe advice, and many GPs feel that they're not qualified to prescribe it. Also, these populations may come from countries where PrEP is not well known and may face internalized stigma.'
About 60% of new infections in Australia occur among overseas-born GBM, said Bavinton. This finding highlights the challenges they face in navigating the healthcare system, along with language barriers, cultural differences, and concerns about stigma.
Sara Whitburn, MBBS, medical director at Sexual Health Victoria and chair of the Sexual Health Special Interest Group of the Royal Australian College of General Practitioners, told Medscape Medical News that she frequently provided advice to overseas-born men on how to buy PrEP online.
Sara Whitburn, MBBS
'But that means you need access to the internet and to feel safe and private. It's doable, but it takes more steps, and we know as human beings, the more steps it takes, the less likely we are to do something,' she said.
Last year, the government announced a $26 million program to provide subsidized access to PrEP for people living in Australia who are not eligible for Medicare. The program has yet to begin.
Long-Acting Injection
But as some patients struggle to take or access a daily pill, the FDA has approved a twice-yearly injection against HIV, lenacapavir, which offers almost complete protection against the disease. It has been hailed as the closest thing to an HIV vaccine.
A spokesperson for Australia's Department of Health said that the Therapeutic Goods Administration had accepted Gilead's application for evaluation of lenacapavir. But with a price tag of US$28,218 (AU$43,000) per year, experts fear that the government will be unable to agree with the company on an affordable price.
'A long-acting injectable like lenacapavir would be a game changer. It gets rid of the problem of adherence. It makes sense,' said Ong. 'We've had a lot of demand for the injection; people want it…but unfortunately it's just going to cost the government too much money.'
Choice is a critical factor for PrEP adherence, and injectables could play an important role in helping Australia reach its elimination goal, said Bavinton. 'It would make a huge difference, so it's really disappointing we may not gain access.' Drug companies need to understand that they can make money by scaling up massively and lowering their cost.
'Last year in Australia, 50,000 people had a prescription for PrEP. It's not a small market. But there's no way any country that subsidizes medicines based on cost-effectiveness will bring such drugs into the market with the current prices they want,' Bavinton added.
'It's about having options,' Whitburn agreed. 'We need a range of options to suit people because taking PrEP every day does not suit everyone.'
Last year, the government couldn't agree with ViiV Healthcare on the price for another HIV prevention drug: a bimonthly long-acting injectable drug, cabotegravir. This impasse suggests that lenacapavir (which has the brand name Yeztugo) will likely face the same problem.
'Yeztugo would be considered for PBS listing if an application were received from the responsible pharmaceutical company,' the Department of Health spokesperson told Medscape Medical News. 'The government cannot list Yeztugo on the PBS without a recommendation from the Pharmaceutical Benefits Advisory Committee (PBAC).' When recommending a drug for listing, the PBAC considers its clinical effectiveness, safety, and cost-effectiveness.
As Australia enters the tail end of the epidemic, it is essential for focus — and money — to remain on the goal, said Ong. 'Investment should go up at the tail of any infectious disease,' he said. 'It will cost more money at the end because we need to find the people who are already infected and protect the rest. But unfortunately, most people won't have that perspective.'
