The U.S. Food and Drug Administration has okayed Gilead Sciences Inc's Sovaldi for the treatment of chronic hepatitis C virus (HCV) infection.

According to the agency, the breakthrough drug can be used to treat the chronic infection without administering interferon, a drug that usually causes flu-like symptoms.

This is the second drug for Hepatitis C approved by the FDA in the past two weeks. On November 22, the agency had given a nod to Olysio (simeprevir).

"Today's approval represents a significant shift in the treatment paradigm for some patients with chronic hepatitis C," said Edward Cox, M.D., director of the Office of Antimicrobial Products in the FDA's Center for Drug Evaluation and Research, according to a news release.

Hepatitis C patients will require $1,000-a-day drug for 12 weeks, which comes to a total of $84,000, Reuters reported.

Sovaldi belongs to a class of drugs called nucleotide analog inhibitors. The drug works by blocking a protein required by the virus to replicate. Depending on the type of HCV infection, the patient can be given Sovaldi and ribavirin or Sovaldi, ribavirin and peginterferon-alfa, the agency said.

Ribavirin and peginterferon-alfa are antiviral drugs used to treat HCV.

The safety and efficacy of the drug was tested during six clinical trials that had a total of 1,947 participants.

Fatigue, nausea and headache were among common side-effects of using the drug-combination.

"I believe that Sovaldi will have a major impact on public health by significantly increasing the number of Americans who are cured of hepatitis C," said Ira Jacobson, MD, a principal investigator in the Sovaldi clinical trials in a press statement released by the company.

Around 3.9 million Americans have chronic hepatitis C virus (HCV) infection and the number of infected people is increasing each year.

HCV is a major cause for liver cancer. Many people who receive a liver transplant or are on the waiting-list for the procedure have a chronic HCV infection.