AHF: Gilead's new HIV med an attempt to evergreen, avoid patent expiration
- The AIDS Healthcare Foundation, led by Michael Weinstein, asserts that Gilead's latest HIV fixed-dose combination (FDC) Genvoya is simply a patent-extension ploy. The same four drug components of Stribild (approved in 2012) also comprise Genvoya.
- Both Stribild and Genvoya contain cobicstat, elvitegravir, emtricitabane and tenofovir. However, the major difference is that Stribild includes tenofovir disoproxil fumarate, while Genvoya uses tenofovir alafenamide.
- Stribild, which costs $28,500 per patient per year (wholesale price), is the most expensive FDC for treating HIV.
Weinstein's assertion that improving the side-effect profile of tenofovir and combining it with the same components as Stribild appears logical, especially in light of the backstory. In January 2013, Gilead filed a Citizen's Petition requesting a patent extension for Stribild from three to five years. The FDA denied the application in October 2014.
As a rule, an FDC is granted three years of exclusivity if there is a previously approved ingredient. However, Gilead pushed for a longer period because there were two newly approved ingredients rather than one. That tactic failed. Now, almost three years later, along comes Genvoya.
While it's easy to call this a textbook case of evergreening, it's important to consider the role of tenofovir. Its new formulation could improve the patient experience, and as a result, improve adherence, which is critical when treating HIV.
When the FDA approved tenofovir as Viread in 2001, it became the backbone for numerous combination regimens and continues to be a treatment cornerstone. However, it was associated with certain toxicities. This newer version is less toxic than the previous version. This makes it easier for patients to gain the therapeutic benefits without as much downside, such as loss of bone density and serious kidney problems. The new form of tenofovir enters the cells, leading to 91% less tenofovir in the bloodstream and a concentration of the drug where HIV replicates most efficiently. That's a notable improvement.
Last October, BioPharma Dive published a three-part series on FDA development trends. The second installment in the series focused on innovation in FDCs for treatment of HIV. The first part of the series can be found here. The second part, focused on HIV, can be found here.