In an update, the US Food and Drug Administration (FDA) has advised hepatitis C patients to be extra cautious while taking direct acting antivirals (DAA) as these medicines can cause or reactivate hepatitis B infection (HBV), particularly if they are currently infected or have a medical history of HBV infection.
In a few cases, the reactivation of HBV in patients resulted in serious outcomes such as liver failure or death.
The FDA has identified 24 cases of HBV reactivation in HBC or HVC co-infected patients who were being treated with DAAs in a duration of 31 months from November 2013 to July 2016. Two patients died and one had to be given a liver transplant.
They noted that HBV reactivation had not been covered during clinical trials submitted for DAA approval because patients with HBV co-infection were excluded from the trials in order to properly evaluate the safety of DAAs and their effects on the liver in HBC infected patients only.
As the study contained cases only submitted to FDA, they say they are unaware of additional similar cases. The count can be higher.
The HCV Guidance Panel took note of the issue and its co-chairman Raymond Chung, MD, said in a press release, “Cases of HBV reactivation (an increase of the HBV virus) during or after DAA therapy for HCV have been reported in HBV/HCV co-infected patients who were not already on HBV suppressive therapy. The severity of these cases have ranged from mild to severe fulminant liver injury that can be life threatening.”
DAAs are a new class of oral drugs approved by FDA to treat HCV infection by preventing the virus from proliferating, therefore reducing the amount of HCV in the body which in most cases cures HCV. Other factors that affect the treatment of HCV are liver problems like liver fibrosis or cirrhosis and human immunodeficiency virus (HIV) infection.
According to CDC, occurrence of hepatitis B has decreased over the years in United States. The number of reported cases has dropped from 5,494 in 2005 to just 2,953 in 2014 while the number of estimated cases is 6.48 times the number of reported cases each year. On the other hand, hepatitis C has increased from 694 reported cases in 2005 to 2,194 cases in 2014 and the number of estimated cases is 13.9 times the number of reported cases each year.
The exact mechanism by which DAAs cause or reactivate HBV is unknown.
Both hepatitis B and C are caused by viruses which are spread through exchange of blood, semen or any other bodily fluid during sexual contact, sharing needles or syringes, or from mother to a baby during pregnancy.
Both type of viruses infect the liver and cause inflammation and severe damage due to which it becomes incapable of processing blood or filtering toxins. Conversely, the liver is unable to produce bile which makes it painful to digest fatty foods. Therefore, people with hepatitis feel a pain in the upper right portion in their abdomen.
Hepatitis is not a serious problem for some people if it is an acute, short-term illness for them but for most people hepatitis can become a long-term chronic illness which is relatively dependent on the age of the infected person. Approximately 90% of infected babies become chronically infected as compared to 2-6% of adults. The best way to prevent hepatitis B is to get vaccinated, however, there is no vaccine for hepatitis C.
Treatment of both acute and chronic hepatitis C is the same. The response rate is higher for people with acute HVC infection than chronic HVC infection and both are treated by a combination of FDA-approved DAAs like ledipasvir/sofosbuvir or ombitasvir/paritaprevir/ritonavir and the recently approved sofosbuvir/velpatasvir. A few other drugs can also be given to patients according to their medical conditions, especially liver problems, but the DAAs are the most commonly employed drugs for hepatitis C.
Should You Get A Test For HBV Before Starting DAA For HCV?
The HCV Guidance Panel of Infectious Diseases Society of America reports that all patients beginning HCV treatment using DAAs should be assessed for HBV. While they don’t have sufficient data on how frequently this occurs, they recommend that all HCV infected individuals should get HBV vaccination and obtain a test for HBV DNA before starting DAA therapy.
They also recommend all doctors and health experts to monitor patients with low or undetectable levels of HBV DNA to effectively hinder HBV reactivation during drug therapy for hepatitis C, and to place all those patients who meet the criteria for HBV DNA levels on HBV therapy.