MONDAY, May 23 (HealthDay News) -- The U.S. Food and Drug Administration on Monday approved Incivek (telaprevir), one of a new class of drugs, to fight chronic hepatitis C infection.

The approval comes after the agency gave a thumbs-up on May 13 to another drug in the same class, called Victrelis (boceprevir).

Both pills appear to help more people clear the virus from their system in a shorter time than older drugs for hepatitis C.

In three clinical trials sponsored by the drug's maker, Massachusetts-based Vertex Pharmaceuticals, a much higher percentage of patients responded favorably when Incivek was added to their care vs. the use of older drugs alone. The length of time needed to treat also fell, from 48 weeks to 24 weeks, the FDA said.

"With the approval of Incivek, there are now two important new treatment options for hepatitis C that offer a greater chance at a cure for some patients with this serious condition," Dr. Edward Cox, director of the Office of Antimicrobial Products in FDA's Center for Drug Evaluation and Research, said in a statement. "The availability of new therapies that significantly increase responses while potentially decreasing the overall duration of treatment is a major step forward in the battle against chronic hepatitis C infection."

Experts working in the field agreed.

"Both patients and physicians are really excited about the approval of this drug, which represents a huge advance in the treatment of hepatitis C. It is expected to almost double the cure rate of this disease," said Dr. Douglas Dieterich, a professor of medicine in the division of liver diseases, at Mount Sinai School of Medicine in New York City.

"We are all very excited about the approval of a new treatment option for hepatitis C," added Dr. Joseph Rahimian, an infectious disease specialist at NYU Langone Medical Center. "This disease has been very difficult to treat, with limited therapeutic options. Many patients have either not been able to tolerate treatment, or have not responded to treatment. Telaprevir will be a welcome addition to treating hepatitis C."

More than 3 million Americans have chronic infection with the hepatitis C virus, which can cause long-term damage to the liver and lead to liver dysfunction or failure, according to the U.S. Centers for Disease Control and Prevention. Hepatitis C is a blood-borne infection; people typically become infected via needle sharing, sharing toothbrushes or razors with someone who is infected, or sexual contact. Infants can pick up hepatitis C from an infected mother.

Hepatitis C infection is a "silent killer" because infected individuals may go for years without displaying symptoms before liver damage becomes apparent. This damage can take the form of cirrhosis, which is also tied to bleeding, jaundice and even liver cancer. According to the CDC, chronic hepatitis C infection is responsible for most of the liver transplants now conducted in the United States.

Incivek is taken three times daily with food. According to the FDA, for the first three months, patients should take Incivek in combination with older medications, peginterferon alfa and ribavirin. People who respond well to that regimen can usually then be treated with Incivek for 24 weeks rather than the usual 48.

Incivek's approval was based on the results of three clinical trials involving about 2,250 adults with hepatitis C who had either never been treated before for the infection, or who had received prior therapy. All patients got Incivek alongside the two older drugs.

Among previously untreated patients, 79 percent saw hepatitis C fall to undetectable levels in blood (suggesting a cure) after adding Incivek to their care. In fact, the "virologic response" rate rose between 20 percent to 45 percent higher across all three studies and all patient groups, compared to standard medications alone, the FDA said.

Most patients on Incivek also saw a halving of the average time needed to achieve a good response to treatment from four years to just two years, according to the FDA. Ninety percent of these "early responders" achieved a sustained virologic response, the agency added.

"When a person achieves a sustained virologic response after completing treatment, this suggests that the hepatitis C infection has been cured," the FDA explained.

Incivek is one of a class of drugs called protease inhibitors. These drugs work by binding with the virus and blocking its proliferation.

Similar results have been seen in trials of Victrelis, sponsored by Merck, the drug's maker. Victrelis is also taken three times a day with food.

Approval for Victrelis came after the drug's safety and effectiveness were tested in two phase 3 trials involving 1,500 adult patients.

Side effects with either Incivek or Victrelis include anemia, nausea and headache, the FDA said. Some patients taking Incivek also experienced fatigue or diarrhea, and itching and rashes. In certain cases, the rash can be severe enough to warrant stopping Incivek or the full three-drug regimen.

Nevertheless, the approval of Incivek and Victrelis "represent the first real advances in the treatment of hepatitis C in 13 years," Dieterich said. "It arrives just in time to help prevent new deaths that were anticipated over the next 10 years in the Baby Boomer generation, the group that has the most Hepatitis C cases."

More information

Find out more about hepatitis C infection at the U.S. National Library of Medicine.