Few therapies can cure most cases of hepatitis C but lower drug prices, testing and better access to treatment are going to be needed to eliminate the liver-destroying virus worldwide, according to a New England Journal of Medicine editorial.

The U.S. government is trying to attain that goal by discouraging states from limiting access to the drugs and encouraging drug companies to reveal their pricing agreements so states can get the best deal on the expensive therapy, said the director of the Centers for Disease Control and Prevention's (CDC) division of viral hepatitis, who coauthored the editorial

"We can look forward to eliminating hepatitis C in the future" with the right combination of pricing and testing, Dr. John Ward told Reuters Health.

The editorial coincides with the formal release of results from four international phase 3 trials showing that the combination of two Gilead Science drugs, sofosbuvir and velpatasvir, can wipe out a chronic hepatitis C virus infection with 12 weeks of therapy.

The sustained viral response rates at 12 weeks, according to the company's ASTRAL studies were at least 97 percent for subtypes of the virus known as genotypes 1, 2, 4, 5 and 6. For type 3, which is harder to treat, the rate was 95 percent.

For patients with advanced cirrhosis of the liver, the cure rate was 94 percent, but only when ribavirin was added to the mix. Serious side effects were seen in 16 percent of those volunteers.

In the groups with less advanced cirrhosis, the rate of serious side effects was usually about 2 percent. Fatigue, headache and nausea were the most commonly reported adverse effect in patients on the drugs.

Curing a hepatitis C infection cuts the odds of liver cancer by 76 percent and the likelihood of early death by 50 percent.

That's the good news. "The public health implications of simple, safe and curative HCV therapies could be profound," Ward and coauthor Dr. Jonathan Mermin, also of the CDC, write in the Journal. However, "patients do not benefit from a drug they cannot afford."

Treatment costs $83,000 to $153,000 for an illness that infects as many as 3.5 million people in the U.S. and up to 150 million worldwide. The numbers are growing as intravenous drug use is increasing. At least half the infected people in the U.S. are unaware they have the virus.

The costs prompted 33 states in the U.S. to require people to have severe liver disease to qualify for the drug combination.

That policy is unwise, Ward said. "Multiple studies have shown that if you wait that long to treat people, you leave them with a small but real risk of developing liver cancer because the liver is already too scarred to completely heal itself."

The federal Centers for Medicare and Medicaid Studies has reacted by notifying the states that people with a chronic HCV infection should not be denied care.

The center also called for drug manufacturers to disclose their value-based pricing agreements, but Ward said the request has no force of law.

"Pharmaceutical companies should be making public their negotiated prices with health plans so the marketplace can take effect and competition can thrive, with better pricing and affordability," he said.

"At a population level, the effect of HCV medications will be determined by affordability and equitable access to HCV testing, care, and treatment," Ward and Mermin write. "Only through these improvements can our focus be directed to what matters most: reducing the morbidity and mortality associated with HCV infection, stopping HCV transmission, and ultimately eliminating HCV as a public health threat in the United States and worldwide."