Sydney — Kyle, a 29-year-old Sydneysider, never knew a time when HIV wasn’t a persistent and pernicious threat — until he began popping a pill to prevent it.

The blue, oval-shaped antiviral tablet, known as Truvada, that Kyle takes daily is the subject of a study in Australia’s New South Wales state that, in less than a year, has helped drive new cases of the AIDS-causing human immunodeficiency virus among gay and bisexual men to the lowest since 1985. "It feels good to be a part of that," says Kyle, a retail assistant who joined a programme called pre-exposure prophylaxis, or PrEP, in January to ease his fear about being infected with HIV during sex on the occasions he doesn’t use a condom. "I do feel a lot safer."

Thirty-six years after a rare lung infection in gay men in Los Angeles heralded the start of the AIDS epidemic in North America, the deadly disease is firmly in retreat globally. For the first time, more than half of all people living with HIV are on virus-suppressing treatment that staves off symptoms and prevents transmission. And thousands of people are using Gilead Sciences’s Truvada in the PrEP trial that’s curbing the spread in communities from London to San Francisco.

PrEP reduces the risk of HIV from sex by more than 90% if the pill — a fixed-dose combination of the drugs tenofovir disoproxil fumarate and emtricitabine — is taken daily.

As cheaper, generic versions of Truvada made by Mylan, Cipla and Teva Pharmaceutical Industries become more widely available, doctors and public health researchers are testing its ability to slash HIV incidence in the developing world, especially sub-Saharan Africa, where it’s mostly transmitted by heterosexual sex.

Impact in Africa?

"The global epidemic is driven in East and Southern Africa, and it’s driven predominantly among women," says Mitchell Warren, executive director of New York-based advocacy group AVAC, which tracks more than 40 ongoing and planned PrEP studies across the world. "To really end the global epidemic, we have got to figure out if oral PrEP can have an impact in Africa like it can in other places."

HIV diagnoses at the UK’s busiest sexual health centre — London’s 56 Dean Street Clinic in Soho — plunged 42% last year, and in San Francisco they have halved since PrEP was approved by the Food and Drug Administration in July 2012.

"You see this very dramatic decline in new infections that wasn’t seen just when we were treating people," says Sharon Lewin, director of the Peter Doherty Institute for Infection and Immunity in Melbourne and a member of the International AIDS Society’s governing council.

Gilead counted 136,000 people taking Truvada as PrEP at the end of the second quarter, compared with 60,000 to 70,000 a year earlier. That’s still a fraction of the 1.2-million American adults at significant risk of becoming HIV-positive who researchers at the Centres for Disease Control and Prevention say are candidates for the regimen.

Profitable pill

Preventative treatment now accounts for about half of the pill’s US sales, Kevin Young, Gilead’s chief operating officer, said in July. The 13-year-old medication’s sales reached $3.57bn in 2016, accounting for almost 12% of revenue for the California-based company.

"It certainly represents a growth opportunity in the US — until generics hit," says Asthika Goonewardene, a biotechnology analyst with Bloomberg Intelligence in New York. "Beyond the societal benefit, this is an old drug, and even with the likely discounts and rebates to ensure coverage, the margin is good and a volume play is very lucrative to Gilead’s earnings."

Gilead doesn’t expect competition from generic versions of Truvada in the US until 2021, CEO John Milligan said last month. Patent protection means that the medicine costs about $17,258 per person a year in the US, Andrew Hill, a senior visiting research fellow in the pharmacology department at Liverpool University, and colleagues told the International AIDS Conference in Paris in July. This compares with an annual cost of about $67 per person for a generic version in India.

Truvada’s patent expired on August 1 in Australia, and Mylan will have found out soon whether a panel advising the government there recommends subsidising a generic version for PrEP, slashing the cost to the Australian government of the preventative treatment. Generics are already available in France, Milligan said in March. "Once it comes off patent, you are going to wind up a getting a much larger use of it," said Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases in a telephone interview. "It will be more accessible from an economic standpoint."

While that will help drive down the prevalence of HIV, it may also have some less desirable effects. Kyle, the PrEP participant in Sydney, says he had one bout of chlamydia in his first six months on the programme and admits his condom usage has gone from "sometimes" to "rarely".

"To be honest, it’s not a big increase in my experience of sexually transmitted infections — not to say that I was constantly catching things," he says.

Another difference now is that Kyle is being screened quarterly for infections as per PrEP guidelines, which means any disease will be treated sooner — reducing the risk of him passing it on — than if he stuck with his usual schedule of a check-up every six-to-nine months. The tests also check for a small risk of kidney damage from Truvada and allow doctors to monitor for a decrease in bone density known to occur in some people after taking PrEP for a few years.

‘Queer warrior’

"No one should be surprised if STI numbers could potentially go up a bit before they go down because you are, for the first time ever, screening people appropriately," said Demetre Daskalakis, deputy commissioner for disease control with the New York City health department, in a telephone interview.

Based on a health department survey, about 30% of men aged 18 to 40 and who have sex with men are on PrEP — and the benefits of it outweigh any risks, according to Daskalakis, who calls himself a "queer health warrior" and posed bare-chested in posters on the New York subway for a campaign in June to encourage citizens to find a new doctor if they can’t talk openly about their sex lives. New HIV infections among gay and bisexual men fell 10% in 2015, the biggest annual drop in New York City’s history of the epidemic.

Beyond the medical benefit of PrEP, the preventative treatment encourages people to talk more openly and confidently about their sexual health and HIV in particular. "If anything, I have more conversations about people’s statuses," says Kyle. "It gives me confidence to say, ‘I am on PrEP. Where are you at?’"


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