Breakthrough hepatitis B drug offers 'functional cure' for first time

For the first time, many people living with chronic hepatitis B may have a functional cure at hand. The US Food and Drug Administration (FDA) has approved the Hibsago (bepirovirsen) injection, which studies show can keep the disease under control without the need for endless doses of antiviral drugs.Chronic hepatitis B (CHB) is a leading cause of cirrhosis and hepatocellular carcinoma (HCC), affecting more than 250 million people worldwide and causing upwards of a million deaths each year.Until recently, many of those with the condition have had no choice but to rely on long-term use of antiviral medication to keep CHB's viral load at bay.“For many people living with chronic hepatitis B, treatment can mean taking antiviral medication for years to keep the virus suppressed,” says Wendy Carter, DO, Acting Director of the Office of Infectious Diseases in the Center for Drug Evaluation and Research in the US. “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. This approval represents an important advance for people living with this serious disease.”To qualify for this first-in-class treatment, individuals must meet a list of conditions, including being free of cirrhosis and on certain antiviral therapeutics for at least six months.According to the FDA, the approval of bepirovirsen was granted under the organization's Priority Review and Breakthrough Therapy Designation category, due to its significant improvement "over existing standard of care."“Despite current therapies, many people living with chronic hepatitis B remain on treatment indefinitely and continue to face the risk of serious liver complications," says Tony Wood, Chief Scientific Officer of the drug's production company, GSK. "For the first time, with Hibsago, US patients have the potential to achieve functional cure after a six-month treatment course, with the added convenience of the option of self-administration after the first dose.”"Functional cure" is key. It's not considered to be a complete cure, instead settling for HBV's DNA and viral protein – HBsAg – remaining undetected for 24 weeks once all other treatment has been stopped. This implies that the immune system has the disease under control without any ongoing intervention.Results from the B-Well phase III trials demonstrated "functional cure" rates of 19% in adults with ≤3000 IU/ml HBsAg, compared to current standard of care alone, which is less than 1% after 12 months. One in five might seem minimal, but it's a massive step forward in combating a deadly disease, and could potentially change – even save – the lives of millions.According to the FDA, "Across the two trials, 24% of patients who received Hibsago met the requirements to stop their existing medicine, compared with none who received placebo. Twenty-four weeks after stopping all hepatitis B treatment, 19% of patients who received Hibsago still had the virus under control, and a protein that signals hepatitis B infection (HBsAg) could not be detected in their blood."CHB is reportedly the cause of an estimated 56% of liver cancers worldwide. While there is an effective vaccine against the disease, hesitancy towards it has grown, and other regions have inadequate access to such preventative medicines, resulting in the ongoing prevalence of hepatitis B.What's more, poor screening has hampered interventions to reduce liver damage over time, while efforts to block its major transmission route – perinatal transfer – have been complicated by myths and misinformation, particularly in the US."This is the start of a new era in treating people living with CHB," says Dr. Norah Terrault, Chief of Gastroenterology & Hepatology, USC Keck Medical Center. “Bepirovirsen offers patients the potential to achieve functional cure after a short period of treatment, a long-standing goal for patients and physicians alike.”Source: GSK