Ritonavir is recommended by WHO as a booster for atazanavir, lopinavir and darunavir. Ritonavir is also commonly known as RTV or r.
Since ritonavir has not been patented in key manufacturing countries such as India, there are several generic suppliers of ritonavir on its own, or in combination with protease inhibitors (a class of antiviral drugs that are widely used to treat HIV/AIDS and hepatitis caused by hepatitis C virus).
Competition among manufacturers for the adult formulations of ritonavir (alone or in combination) may be limited to countries where there are no patents, or where a compulsory license has been issued. As for pediatric formulations for children under three, market competition (or market entry by generics with new formulations) is likely to take place in countries covered by the Medicines Patent Pool license or in countries where there are no patents in force.
The compound patent on ritonavir was due to expire at the end of 2013. It is unclear if it is still in force in Brazil and Mexico. Nevertheless, there are other patents that are also relevant to the production and sale of ritonavir.
A patent on the polymorph, which expires in 2019, has been granted in Argentina, China, Indonesia, Malaysia, Mexico, Philippines and Turkey. It is pending in Thailand.
A patent on the tablet formulation, expiring in 2024, was granted in Albania, Bosnia, China EAPO member countries, Indonesia, Mexico, Montenegro, South Africa, Sri Lanka, Turkey, Ukraine and Viet Nam, and appears to be pending in Brazil, Ecuador and Nicaragua.
In December 2014, certain pediatric formulations of LPV/r and ritonavir were licensed to the Medicines Patent Pool. The license includes 102 countries and allows for the sale of generic versions of ritonavir outside the licensed countries, where there are no patents in force.
Compulsory licenses were granted on ritonavir or its combination with lopinavir in Ecuador, Indonesia and Thailand.
Currently available combinations that include ritonavir are LPV/r and ATV/r. Patents on ritonavir and on LPV/r tablets are likely to delay competition in certain markets (see lopinavir).