The US Food and Drug Administration (FDA) has granted breakthrough therapy designation to Bluejay Therapeutics’ fully human immunoglobulin G1 (IgG1) monoclonal antibody, brelovitug, to treat chronic hepatitis delta (CHD).

Also referred to as BJT-778, brelovitug targets the hepatitis B virus' surface antigen.

The antibody neutralises and eliminates hepatitis B and D virions, as well as depleting HBsAg-containing subviral particles, making it a safe treatment alternative for the condition.

By demonstrating immunomodulatory functions in chronic hepatitis B (CHB) individuals, brelovitug aids in rebuilding antiviral immunity.

This could contribute to a functional cure for CHB when used along with other therapeutic agents.

The company is currently investigating brelovitug for the treatment of both CHD and chronic hepatitis B virus infections. It previously gained orphan and PRIME designation from the European Medicines Agency (EMA).

There are no currently approved treatments for CHD in most nations worldwide as well as in the US.

Bluejay Therapeutics founder and CEO Keting Chu stated: “Chronic hepatitis delta is the most aggressive form of viral hepatitis and the lack of approved treatments in the US creates a major unmet need for patients.

“Breakthrough therapy designation recognises the potential of brelovitug to transform the lives of people living with CHD. We look forward to initiating a global pivotal trial as soon as possible to meet our goal of improving patients’ lives.”

The company develops treatments for serious viral and liver conditions. It is advancing programmes including a TLR9 agonist, cavrotolimod, and a liver-targeted HBV transcript inhibitor, BJT-628, to develop a combination regimen that delivers a functional cure for CHB.

In June 2024, the company released positive preliminary data from a Phase II trial of brelovitug for the treatment of CHD.