FDA approves Hibsago as first antisense treatment for hepatitis B
The FDA approved GSK's Hibsago for some adults with chronic hepatitis B, according to the agency's announcement. In trials, 19% of patients kept the virus under control 24 weeks after they stopped all treatment. The drug has a boxed warning for liver reactions and low platelets.
The Food and Drug Administration on Tuesday approved Hibsago (bepirovirsen), used with existing antiviral therapy, to treat chronic hepatitis B in certain adults without cirrhosis, according to the FDA's announcement. The FDA said Hibsago is the first FDA-approved antisense oligonucleotide to treat chronic hepatitis B. The approval went to GSK.
The drug is approved for adults who have taken hepatitis B antivirals for at least six months, have suppressed virus levels in their blood and have surface antigen levels of 3,000 IU/mL or less on an FDA-authorized test, the agency said. The FDA also authorized a Roche test to help select and monitor patients.
Hibsago is injected under the skin for up to 24 weeks alongside existing medicine, which patients keep taking for at least 24 weeks after their last dose, the FDA said. Across two trials, 24% of patients on Hibsago met the requirements to stop their existing medicine, compared with none on placebo. Twenty-four weeks after stopping all treatment, 19% still had the virus under control and no detectable surface antigen, according to the FDA.
HCPLive reported the trial-by-trial results from the phase 3 B-Well 1 and B-Well 2 studies published in the New England Journal of Medicine. Functional cure was reached by 20% of patients on the drug in B-Well 1 and 19% in B-Well 2, versus none on placebo, HCPLive reported. A functional cure does not necessarily mean the virus is gone or that control lasts for life, according to HCPLive.
Hibsago carries a boxed warning for serious liver reactions and low platelet counts, which can raise the risk of life-threatening bleeding, the FDA said. Adverse events occurred in 91% of patients on the drug and 73% on placebo in pooled analyses, HCPLive reported. The most common side effects are injection site reactions, fever, fatigue and headache, the FDA said.
"Hibsago provides a new treatment approach that gives some patients the possibility of maintaining control of the virus after all chronic HBV treatment has ended," said Wendy Carter, acting director of the FDA's Office of Infectious Diseases. Chronic hepatitis B can lead to cirrhosis and raises the risk of liver cancer, according to the FDA.
What we know: The FDA approved Hibsago for some adults with chronic hepatitis B, and 19% of trial patients kept the virus controlled after stopping treatment.
What we don't: Its price and how insurers will cover it. Only HCPLive has reported this independently so far, and NewsHabit hasn't seen independent confirmation.
Where outlets agree The details come from the FDA's approval announcement, which HCPLive also reported with trial results from the New England Journal of Medicine.
Where they differ The FDA reports that 19% of Hibsago patients across both trials kept the virus controlled after stopping treatment, while HCPLive reports functional cure rates of 20% in B-Well 1 and 19% in B-Well 2.