April 30, 2018
I’m a hepatitis C drug that has been fought over in court.
What molecule am I?
Image of Sofosbuvir 3D Image of Sofosbuvir

Hepatitis C is a burgeoning disease that is still in search of a one-drug-fits-all solution. Currently, each hepatitis C virus genotype is treated with a pharmaceutical cocktail that consists of a mixture of antivirals, most of whose names end with “vir”.

Sofosbuvir is one such compound. It was discovered in 2007 by Michael Sofia at Pharmasset (now part of Gilead Sciences) and approved for use in the United States by the Food and Drug Administration in 2013. The FDA approval was for the combination of sofosbuvir and ribavirin, an antiviral that dates back to 1972. Sofosbuvir is the active ingredient in Gilead’s products Sovaldi and Harvoni, ads for which you may have seen on TV.

Sofosbuvir was the subject of a high-profile patent lawsuit involving Gilead and drug giant Merck. Merck contended that sofosbuvir was patterned after a patent awarded to Idenix Pharmaceuticals, a company that Merck had acquired. After a series of trials, a federal jury ordered Gilead to pay Merck US$2.54 billion (that’s right, billion) for infringing the Idenix patent.

Gilead appealed; and this past February, the judge in a US district court overturned the award, writing that the Idenix patent was too broad and that a skilled chemist could not easily derive sofosbuvir from the information in the patent. For the same reason, the judge invalidated the patent.

Merck has vowed to appeal the overturn ruling. 


Sofosbuvir hazard information

GHS classification*: skin irritation, category 2    
H315—Causes skin irritation 
GHS classification: skin sensitization, category 1
H317—May cause an allergic skin reaction
GHS classification: serious eye damage, category 1
H318—Causes serious eye damage Chemical Safety Warning
GHS classification: respiratory sensitisation, category 1
H334—May cause allergy or asthma symptoms or breathing difficulties if inhaledChemical Safety Warning
GHS classification: specific target organ toxicity, single exposure, respiratory tract irritation, category3
H335—May cause respiratory irritationChemical Safety Warning
GHS classification: germ cell mutagenicity, category 2
H341—Suspected of causing genetic defectsChemical Safety Warning
GHS classification: reproductive toxicity, category 2
H361—Suspected of damaging fertility or the unborn childChemical Safety Warning
GHS classification: specific target organ toxicity, single exposure, category 1
H370—Causes damage to organs Chemical Safety Warning
GHS classification: hazardous to the aquatic environment, long-term hazard, category 4
H413—May cause long-lasting harmful effects to aquatic lifeChemical Safety Warning

*Globally Harmonized System of Classification and Labeling of Chemicals. Explanation of pictograms.

Sofosbuvir fast facts

CAS Reg. No.1190307-88-0
Molar mass529.46 g/mol
Empirical formulaC22H29FN3O9P
AppearanceWhite to off-white crystals or powder
Melting point94–125 ºC*
Water solubility≈105 mg/L*

*Depends on crystalline polymorph.


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