U.S. regulators on Friday approved Gilead Sciences Inc's Sovaldi as a potentially easier cure for chronic infection with the liver-destroying hepatitis C virus.
The once-a-day pill is the first approved to treat certain types of hepatitis C infection without the need for interferon, an injected drug that can cause severe flu-like symptoms.
Hepatitis C, which is often undiagnosed, affects about 3.2 million Americans, killing more than 15,000 each year, mostly from illnesses such as cirrhosis and liver cancer.
Most patients will be treated with the $1,000-a-day drug for 12 weeks, resulting in a total list price of $84,000, according to Gilead spokeswoman Cara Miller.
"Today marks a landmark advance in the treatment of hepatitis C, opening up new opportunities to stop the spread of this virus and the ravages of this disease," Dr John Ward, director of the Centers for Disease Control and Prevention's division of viral hepatitis, said in a statement.
Last year, the CDC recommended that all baby boomers, born from 1945 to 1965, be tested for the virus. Introduction of blood and organ screening in the 1990s has dramatically lowered infection rates for younger generations.
Gilead said Sovaldi, also known as sofosbuvir, can be used in combination with ribavirin, an older antiviral pill, for patients with genotypes 2 and 3 infections, which account for about 28 percent of U.S. patients infected with the virus.
For patients with genotype 1, which accounts for about 70 percent of U.S. infections, the new drug must still be used with both interferon and ribavirin, although it can be considered for use in patients with genotype 1 infections who cannot use interferon.
Patients with the much less common genotype 4 infections will also be treated with a three-drug combination.
The Gilead drug's approval was supported by several studies showing that it helped to eradicate the virus in significantly more patients, with fewer side effects, than the current drug regimen.
Sovaldi is the first in a new class of medications known as nucleotide analogue inhibitors, or "nukes," designed to block a specific protein that the hepatitis C virus needs to copy itself.
Analysts, on average, have forecast Sovaldi sales of $1.9 billion next year, according to BMO Capital Markets.
Gilead has said it plans to file in the first half of next year for FDA approval of an all-oral regimen for genotype 1 patients. Companies including Bristol-Myers Squibb, AbbVie and Boehringer Ingelheim are also spending millions to develop new hepatitis C treatments.
Shares of Gilead, which have nearly doubled over the past 12 months, were up half a percentage point at $74.39 in after-hours trading. The shares rose 1 percent to close at $73.99 in regular Nasdaq trading on Friday.