There is no doubt that PrEP offers a true breakthrough in HIV prevention. It will be a critical addition to other proven prevention tools such as condoms, needle exchange, and voluntary male medical circumcision.
The key downside in rich countries is that it is expensive. At $8,000 to $14,000 per year, getting everyone on PrEP who needs it will not be cheap. Insurance companies have largely been covering PrEP and some governments – like state Medicaid programs and the city of San Francisco – are stepping up to help expand access to populations particularly impacted by HIV where prevalence remains high. But much more will have to be done to get PrEP to the populations that are most heavily impacted by HIV – especially men who have sex with men of color – who due to structural racism and mass incarceration in America are much more likely to be uninsured and not connected with the health care system. While Gilead Sciences, the maker of Truvada, the only medicine currently approved for PrEP, has access programs, governments will have to take on the major costs, not to mention programmatic responsibilities, of extending access to PrEP (and hopefully one day health insurance) to these populations.
Clearly all parties spending on PrEP would benefit from lower prices, but will this happen and when? The good news in almost every developing country is that Truvada is available for as little as $70 per year. Following new WHO recommendations on the use of PrEP, governments and global funders should be able to provide it at very low cost to populations that are particularly at risk for HIV infection.
In the US and other rich countries, there is a different story. Truvada is a combination of two drugs – tenofovir disoproxil fumarate (TDF) 300mg and emtricitabine (FTC) 200mg. The patent on TDF ends in 2018 in the US but the combination patents on TDF/FTC together lasts until 2024 meaning that for Truvada itself prices will likely remain high for a long time.
However, there is a potential way around this problem. Another HIV medicine, lamivudine (3TC), is considered to be interchangeable with FTC. 3TC is already off patent and there are no combination patents with TDF. This means that potentially from 2018 there could be TDF/3TC used for PrEP at generic prices a fraction of the current cost of Truvada. Over time, generic medicines tend to drop to 20% of the cost of the original branded product or less which would mean prices below $3,000 per year. Another solution could be to take TDF and FTC as separate, individual pills.
There is another chapter to this story. Gilead Sciences, the company that developed TDF, is currently developing a new version of tenofovir called tenofovir alafenamide (TAF). TAF is in phase III clinical trials and could be approved by the FDA by next year. TAF has a number of advantages including fewer side effects and a lower dose, meaning that it will be cheaper to manufacture – though that will only affect the eventual generic price and not the price it is sold at by Gilead.
For treatment of HIV, it is likely that TAF will become the new standard of care and Truvada will be replaced with a TAF/FTC combination. TAF patents last until 2021. To-date, TAF has not been tested to show if it is effective for use in PrEP but there is a likely chance that it is. If TAF proves to be as effective for PrEP as TDF is, TAF/FTC would likely become the new standard of care for PrEP, meaning that prices could stay high.
So what can be done? As I said, PrEP in developing countries is already available at very low cost. Steps taken by organizations such as the Medicines Patent Pool in collaboration with Gilead will ensure that any new PrEP combination with TAF would also be available at low cost in most developing countries.
For the US and other rich countries, the path would seem to be focusing on the combination of TDF/3TC. TDF is very effective and has few side effects for most people who take PrEP and the millions of patients who take TDF for treatment of HIV around the world. So it would make sense to continue to use it for patients who tolerate it well even if TAF becomes the new standard of care. This will be particularly critical for government programs to increase the number of people who can receive PrEP per dollar spent and in European countries that have been slow to take up PrEP due to the cost.
Looking further down the road, patients will likely receive quarterly injections for PrEP. The initial costs of these drugs is likely to be quite high, but in the long run for a variety of reasons, these injectables may be more affordable once they become available as generics. I’ll write about all this another time.
Disclosure: I consult for the Medicines Patent Pool. The views expressed here are my own.
Thanks to Patrick Hazelton and Luke Habberstad who provided very helpful comments.