UPDATED: New era for hep C treatment begins with FDA OK for Gilead's sofosbuvir

The FDA has given the green light to marketing sofosbuvir for hepatitis C, one of the most eagerly anticipated new drug approvals of the year. Gilead's ($GILD) therapy, which will be marketed as Sovaldi, will open the door to a new generation of treatments that doesn't require interferon injections--freeing patients from an arduous regimen tied to a host of nasty side effects.

The historic nature of the approval for sofosbuvir--the first in a new class of nucleotide polymerase inhibitors, or 'nukes'--wasn't lost on the FDA.

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

Fast behind this therapy is a whole wave of related drugs that will create a series of cocktail therapies for hepatitis C. AbbVie ($ABBV) and Bristol-Myers Squibb ($BMY) are closest behind Gilead, which can now start reaping a reward for a product that cost the biotech a whopping $11 billion in the high-profile Pharmasset acquisition. And Gilead is rushing along a combination approach that promises to knock down the virus in a wide variety of genotypes. Until then, interferon will sometimes be required for some patients.

"There are several different types of HCV infection," notes the FDA. "Depending on the type of HCV infection a patient has, the treatment regimen could include Sovaldi and ribavirin or Sovaldi, ribavirin and peginterferon-alfa. Ribavirin and peginterferon-alfa are two drugs also used to treat HCV infection."

Gilead did surprise analysts with its announcement that under the label granted by the FDA, genotype 1 patients ineligible for interferon may be "considered" for an all-oral treatment, a move that could open up the market much faster than initially anticipated.

Analysts expect Sovaldi to go on to earn perhaps $7 billion a year, marking it as a potential megablockbuster that will further propel earnings at Gilead. And with patients being "warehoused" in anticipation of the approval, there's likely to be a big rush for this new drug.

To start harvesting its billions, Gilead is pricing a 24-week supply of the drug at $84,000, well over the current price for standard therapies. Doctors Without Borders fired a quick shot against the company, saying that Sovaldi "won't do much good if it's unaffordable for the more than one hundred million people with hepatitis C in developing countries." But Gilead has developed a thick hide after enduring years of harsh criticism for its HIV drug prices and isn't likely to budge an inch.

The biotech's single-minded devotion to its bottom line was on full display when executives turned a cold shoulder to Bristol-Myers Squibb's appeal to follow up on stellar mid-stage results for a combo therapy matching sofosbuvir with daclatasvir and launch pivotal trials. Gilead decided to stick with an in-house cocktail instead, regardless of any affect that decision could have on patients.

None of this, though, weighed in on the FDA's decision. Gilead's victory lap at the agency was marked by a unanimous panel review as well as an internal review that included high praise for this therapy. 

The FDA concluded that "the currently available data support a favorable benefit-risk assessment for the use of sofosbuvir as part of a combination regimen for the treatment of chronic hepatitis C. In the HCV GT 2 and 3 populations, the sofosbuvir and ribavirin combination regimen provides the first all-oral, interferon-free treatment, as well as a shorter treatment duration and improved safety profile compared to the current standard of care interferon-based regimen. In addition, SOF+RBV provides a therapeutic option for patients who are ineligible, intolerant or unwilling to take interferon-based regimens, thus addressing an unmet need in this patient population."

Gilead was also quick to herald the cutting-edge approval.

"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 Dr. Ira Jacobson, chief of the division of gastroenterology and hepatology at Weill Cornell Medical College and a principal investigator in the Sovaldi clinical trials, in a company statement. "In clinical studies, Sovaldi in combination with other agents achieved very high cure rates while shortening the duration of treatment to as little as 12 weeks and reducing or completely eliminating the need for interferon injections, depending on the viral genotype."

Sovaldi marks the FDA's OK for its third "breakthrough" therapy, a designation intended to speed along breakthrough drugs. It also marks the end of a short reign for Vertex's ($VRTX) Incivek and Merck's ($MRK) Victrelis, which offered their own big advances at the time.

- here's the release from the FDA
- read's Gilead's statement