A New Pill Makes Hepatitis C a Curable Disease

In December 2013, the United States Food and Drug Administration approved sofosbuvir, an oral medication designed to treat hepatitis C. Before this decision, therapies for the viral liver infection relied on regimens centered on peginterferon, an injectable substance administered over six to twelve months. These traditional treatments yielded cure rates of 70 percent or less and carried harsh side effects, such as anemia, severe fatigue, and depression. Medical professionals routinely delayed treatment for individuals when clinical trials revealed that an oral nucleotide analog could transform clinical outcomes.

Sofosbuvir originated in 2007 through research directed by Michael J. Sofia at the biotechnology company Pharmasset. Clinical testing in human subjects began in 2010, prompting Gilead Sciences to purchase Pharmasset the following year for approximately 11 billion dollars. The compound functions as a prodrug designed around the ProTide approach, which integrates the initial phosphate group directly into the drug structure to bypass a slow enzymatic step. Once activated in the liver into an active antiviral agent, it acts as a defective substrate for the viral NS5B RNA polymerase, disrupting the replication cycle of hepatitis C.