widenews desk: Drugs approved in recent years that can cure hepatitis C may have severe side effects, including liver failure, a new report suggests.
The number of adverse events appears relatively small, and the findings are not conclusive. But experts said the report was a warning that should not be ignored. It involves nine widely used antiviral drugs that were heralded as a huge advance because they greatly increased cure rates, seemingly with few side effects.
Problems might arise from some doctors’ prescribing incorrectly, giving the drugs to patients with liver function too poor to tolerate them or benefit from them.
Hepatitis C is an enormous public health problem. Caused by a virus, it leads to chronic liver disease in most people who contract it, and some eventually develop cirrhosis and liver cancer.
The virus is blood-borne, and the most common source of infection is needle-sharing among people who use illicit drugs. In countries where the blood supply is not screened, transfusions still pose a risk. Needlestick injuries and other hospital accidents may also cause some cases.
There is no vaccine to prevent the infection, so treatments have long been eagerly sought. Sovaldi and Harvoni, both the drugs made by Gilead Sciences and priced at $1,000 a pill, with billions of dollars in sales. Sovaldi was approved in 2013, and Harvoni in 2014. These drugs and other antivirals can cure the disease in 12 weeks in many patients.
Earlier drugs were less effective, had to be taken for much longer and had harsh side effects that left many patients unable to finish the course of therapy.
A spokesman for Gilead, Mark Snyder, wrote in an email, “We closely assess both post-marketing safety reports as well as safety data from our clinical trials on an ongoing basis and have found no suggestion of a causal relationship between Sovaldi or Harvoni and liver failure.”
He added that Gilead’s drugs had been approved for people with severe liver disease from hepatitis C, and that some would inevitably suffer liver failure despite the best treatment.
In October, the F.D.A. identified the first major safety problem caused by the nine antiviral drugs. In 24 patients, the drugs wiped out hepatitis C, but also reactivated hepatitis B infections that had been dormant. Two of those patients died, and one needed a liver transplant. The agency said there were probably additional cases that had not been reported.
As a result, the agency required that a boxed warning, its most prominent advisory, be added to the labeling of the newer antivirals, telling doctors to screen and monitor for hepatitis B in all patients taking the drugs for hepatitis C. Infection with both viruses is not common, and how the reactivation occurs is not known. The problem was not detected during premarket testing of the drugs because patients who currently had hepatitis B or who had a history of it were not allowed into the studies.
The other cases of liver failure are a separate problem. It was important for doctors prescribing the newer drugs to test patients’ liver function thoroughly first, because liver disease can be deceptive, and people who look well may actually be on the brink of liver failure and therefore not candidates for the drugs.