Tenofovir disoproxil fumarate is the patented drug of Gilead. Gilead Sciences sells tenofovir disoproxil under the brand name Viread.
Tenofovir disoproxil fumarate is a prodrug of tenofovir which is a fumaric acid salt of bis-isopropoxycarbonyloxymethyl ester derivative of tenofovir. In vivo tenofovir disoproxil fumarate is converted to tenofovir, an acyclic nucleoside phosphonate (nucleotide) analog of adenosine 5′-monophosphate.
Tenofovir exhibits activity against HIV-1 reverse transcriptase. It is indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection. Tenofovir is also indicated for the treatment of chronic hepatitis B in adults.
Viread’s patent saga
Though Gilead has a global patent for Viread till 2018, the US Patent and Trademark Office’s (USPTO) rejected Gilead Sciences’ patent application for the AIDS drug.
In India Cipla has been marketing a generic version of tenofovir at a cost of $700 per person per year, for some time now. Gilead’s tenofovir costs $5,718 per patient per year in developing countries.
To curtail this, Gilead signed license agreements with 11 Indian companies for manufacturing and selling Viread in 95 countries, including India. The agreement signed in the year 2007 gave access to Gilead’s technology to manufacture and sell Tenofovir. Cipla, which refused Gilead’s licensing offer, challenged Viread’s validity by filing a pre grant opposition. Cipla argued that the grant of the patent in India will make the HIV drug unaffordable to patients worldwide.
However, Indian firms who entered into agreements with Gilead -Matrix Laboratories, Aurobindo Pharma, JB Chemicals, Alkem, Shasun Chemicals, Strides Acrolab, Emcure and Hetero Drugs -continued to market the drug.
Gilead sells tenofovir alone and in combination with other drugs like Truvada and Atripla. Taken together, the three HIV treatments generated $3.1 billion in sales last year, according to the company reports. Viread registered sales of $359.2 million for the six months ended June 30.
The President’s Emergency Plan For AIDS Relief (PEPFAR) was aimed to fight the global HIV/AIDS pandemic over five years (2003–2008) from United States President George W. Bush with a commitment of $15 billion. The goals of PEPFAR include support for treatment for 2 million HIV infected people, support for prevention of 7 million new infections, and support for care for 10 million people infected or affected by HIV/AIDS. PEPFAR has been called the largest health initiative ever initiated by one country to address a disease.
Cipla: A leader in anti-retrovirals
Two months ago, Cipla received approvals for two drugs namely stavudine 1 mg/ml and levetiracetam 250 gm, 500 gm,750 from USFDA.Stavudine is used for use in combination with other antiretroviral agents for the treatment of HIV infection in adults and children.
Levetiracetam tablets are indicated as adjunctive therapy in treatment of myoclonic seizures in adults and adolescents from 12 years of age with juvenile myoclonic epilepsy.
It has to be recalled that the US Food and Drug Administration (FDA), issued warning letters to Cipla following inspections in its manufacturing facility in Bangalore. US FDA has reportedly found out nearly a dozen variations in the standard operating procedure for good manufacturing practices (GMP) quality norms to be followed by the drug manufacturer. US FDA has issued inspectional observations to Cipla seeking explanations for the violations.
Cipla is one of the world’s largest manufacturer of antiretroviral drugs (ARVs) to fight HIV/AIDS. Roughly 40% of HIV/AIDS patients undergoing antiretroviral therapy worldwide take Cipla drugs.