GSK gets FDA fast track for chronic hepatitis B treatment

GSK announced on Monday that bepirovirsen, an investigational antisense oligonucleotide (ASO) aimed at treating chronic hepatitis B (CHB), had been granted fast track designation by the US Food and Drug Administration (FDA).

The FTSE 100 pharmaceuticals giant said such a designation was given to drugs designed to address serious conditions and fulfil unmet medical needs, streamlining their development and review process.

It said the request for the designation was prompted by bepirovirsen's potential to address the significant unmet medical need within CHB, a condition affecting around 300 million individuals worldwide.

Current treatment options for CHB offered only a minimal functional cure rate, ranging from 2% to 8%, which was deemed clinically insignificant.

Functional cure entails reducing hepatitis B virus DNA and viral proteins to undetectable levels in the blood, controllable by the immune system without medication.

Currently-available oral antiviral therapies, known as nucleoside/nucleotide analogues (NAs), merely suppress the virus without directly lowering hepatitis B surface antigen (HBsAg), crucial for achieving functional cure.

Bepirovirsen, on the other hand, showed potential to achieve a clinically meaningful functional cure response when combined with oral NAs, as affirmed by positive outcomes from the B-Clear and B-Sure clinical trials.

B-Clear specifically indicated that patients with low baseline hepatitis B surface antigen levels are most likely to benefit from bepirovirsen treatment.

Furthermore, bepirovirsen was being explored as a potential backbone therapy in future sequential regimens to pursue functional cure across a broader spectrum of CHB patients.

The ongoing phase three III programme, B-Well, aimed to further validate the promising results.

“The B-Clear trial consisted of two parallel cohorts, one for patients receiving NA treatment and the other for patients who were not-on-NA,” GSK explained in its statement.

“Longer term efficacy and durability of response is being investigated in the B-Sure trial, which follows participants from the B-Clear study for an additional 33 months and includes criteria for stopping NA therapy to evaluate the potential for functional cure in patients who successfully stop all medication and continue to demonstrate no serologic evidence of hepatitis B surface antigen (HBsAg) or HBV DNA.”

At 0803 GMT, shares in GSK were down 0.22% at 1,656.4p.

Reporting by Josh White for Sharecast.com.