European CDC cautious about PrEP

The European Centre for Disease Prevention and Control (ECDC) has issued a paper saying that it cannot make a clear Europe-wide recommendation on the use of pre-exposure prophylaxis (PrEP), and that it would require clearer data on efficacy, cost-effectiveness, side-effects, resistance and its impact on condom use before making a recommendation.  

Recently, two important public health organisations have recommended pre-exposure prophylaxis (PrEP) as an additional prevention strategy, especially for gay men.

PrEP is already licensed for use in the US and in May 2014 the US Centers for Disease Control and Prevention (CDC) recommended its use for anyone HIV-negative with an HIV-positive partner, for gay men who haven’t used condoms consistently or who have had a sexually transmitted infection (STI) in the last six months, for people who inject drugs who have shared needles, and for heterosexuals who have had condomless sex with a high-risk partner.

This month, the World Health Organization (WHO) issued a comprehensive set of prevention guidelines which continued to recommend “the correct and consistent use of condoms” as a highly effective HIV prevention strategy, but which also included the new recommendation that “Among men who have sex with men, PrEP is recommended as an additional HIV prevention choice within a comprehensive HIV prevention package”. This was widely misreported as WHO wanting all gay men to take PrEP.

No European agency has issued a public statement on PrEP since March 2012, when the European Medicines Agency (EMA) published a consultation paper on PrEP. In the end this consultation was never completed. European agencies may therefore have felt under some pressure to make a statement on PrEP.

The ECDC has now issued a paper taking a much more cautious line on PrEP. It comments that “PrEP is an antiretroviral therapy-based HIV prevention strategy which merits some mention” and in an accompanying presentation says that it “shows promising prospects for inclusion in the ‘HIV prevention toolbox’ in Europe”.

There is no common approach on PrEP across Europe, the ECDC comments. Apart from the never-completed EMA paper, the British HIV Association/British Association for Sexual Health and HIV issued a statement on PrEP in which they said they wanted to see more European research before making a decision on PrEP. There are two scientific studies of PrEP currently underway in the UK and France, PROUD and IPERGAY, (PROUD’s principal investigator, Professor Sheena McCormack, was also an author of the BHIVA/BASHH statement) but they will not report efficacy data for a couple of years. Because of this, the ECDC says that “This makes it difficult to provide a clear recommendation at present that would apply to the entire European Union”.

The ECDC says that “despite some encouraging results, a number of questions remain unanswered regarding PrEP. For example, the cost-effectiveness of PrEP in the long term requires further investigation, as it is likely to depend on high levels of adherence to the treatment.”

There have been many papers modelling the cost-effectiveness of PrEP. The ECDC mentions one based on the US setting that computes that PrEP could be cost-effective in terms of preventing HIV infections, but would still be very expensive. If 50% of high-risk gay men used PrEP (taking the CDC’s definition of unprotected sex in the last six months), this would prevent 30% of HIV infections over the next  20 years that would otherwise have occurred, and reduce HIV prevalence in high-risk gay men from 31% to 23% – a 26% relative reduction. This PrEP programme would cost $2.1 billion every year for the next 20 years; taking HIV infections avoided into account, it would still cost $1.8 billion. The paper cited found that PrEP would be cost-effective by US standards only if it cost less than $5475 per person per year or if its efficacy was more than 75%.

A number of other modelling papers on PrEP’s cost-effectiveness have found that, in various global settings, it could be everything from cost-saving to completely unaffordable, depending on two crucial factors: the price paid for PrEP drugs and how tightly it is targeted at people whose risk of HIV, to quote an early paper on the iPrEx trial is not just “high, but imminent”. 

ECDC acknowledges PrEP “could be particularly effective for persons at very high risk of HIV acquisition, such as sexual or injecting partners of people living with HIV” but says a number of questions need to be answered before a Europe-wide recommendation is possible.

These include:

• Can countries afford to invest in PrEP? HIV treatment costs are only going to increase.
• Is it justifiable to provide ART to HIV-negative individuals before having reached sufficient ART coverage for people who are HIV positive?
• Will PrEP divert resources away from other prevention activities?
• Given the high costs of PrEP, how do we determine who will be eligible?
• How will we ensure that adherence is maximised?
• Will the use of PrEP impact on condom use? If so, will overall transmission risk increase or decrease as a result of PrEP?

The ECDC concludes by saying that “Future research needs in the use of ART for prevention of HIV transmission should focus on obtaining the evidence on the efficacy of ART in reducing onward sexual transmission in the wider population” – in other words, that the public-health effectiveness of ARV-based prevention strategies in general, and not just PrEP, needs more research and evaluation in Europe.