Breakthrough: FDA Approves First Drug Offering a 'Functional Cure' For Chronic Hepatitis B

Chronic hepatitis B affects millions of people globally and is responsible for over a million deaths each year, according to ScienceAlert. The condition can lead to organ failure, scarring, or cancer. ScienceAlert reported that the US Food and Drug Administration approved the drug bepirovirsen, developed by the British pharmaceutical company GSK under the brand name Hibsago, following phase 3 clinical trial results published in the New England Journal of Medicine. Dealroom and Yahoo News Canada reported that Health Canada has also approved Hibsago as a finite therapy to achieve a functional cure. According to ScienceAlert, the drug is described as a functional cure because it suppresses the virus to undetectable levels in the blood, allowing patients to stop treatment while the infection stays under control.

ScienceAlert stated that a six-month course of bepirovirsen achieved a functional cure response in 233 out of 1,220 participants, representing 19 percent, compared to 0 out of 614 participants on a placebo drug. In those responsive patients, the virus remained undetectable for at least 24 weeks after all treatment stopped, which was 72 weeks after the trial began. According to Yahoo News Canada and the Calgary Herald, Dr. Carla Coffin, a hepatology clinician at the University of Calgary, explained that the virus entrenches itself by building a permanent blueprint in cells and weaving pieces into human DNA to create viral proteins. Hibsago latches onto the virus's instructions, sends enzymes to degrade the process, and jolts the immune system to fight the infection.

ScienceAlert noted that the drug is administered via weekly injections and was given alongside existing pill treatments, which could then be stopped for patients given the all-clear. Tony Wood, Chief Scientific Officer at GSK, stated that patients have the potential to achieve a functional cure after a six-month course with the option of self-administration after the first dose. Wendy Carter, Acting Director at the FDA's Office of Infectious Diseases, reported that the drug provides a new approach that gives some patients the possibility of maintaining control of the virus after all chronic HBV treatment has ended. However, ScienceAlert noted that some patients experienced serious side effects, including liver inflammation, which requires regular blood monitoring.

Yahoo News Canada and the Calgary Herald reported that around 80 percent of participants did not reach a complete functional cure, though the drug weakened the virus enough for some to be treated with antiviral pills. Dr. Coffin stated that GSK is looking into potential re-treatment studies for patients who almost reached zero virus levels by giving them a shorter course of therapy. ScienceAlert noted that patients with lower levels of a key CHB protein at the start of treatment had a higher chance of the drug working, which could be tested beforehand. Researchers also plan to study how the treatment might be combined with other drugs to increase effectiveness, while GSK aims to make it available to more patients worldwide.