Following unexpected serious adverse events, including 1 patient death, Spring Bank Pharmaceuticals has decided to discontinue the development program of inarigivir soproxil, an investigational oral immunomodulator for chronic hepatitis B virus (HBV).

Inarigivir soproxil was being investigated in a number of simultaneous phase 2 trials; in total 199 individuals with chronic HBV infection were enrolled. The oral drug candidate was designed to activate within hepatic cells retinoic acid-inducible gene 1 (RIG-I), which has been shown to inhibit HBV viral replication and induce the intracellular interferon signaling pathways for antiviral defense.

In December 2019, the Company announced that it would stop dosing patients in the Catalyst 2 trial. Lab findings revealed evidence of hepatocellular dysfunction and alanine transaminase elevation that was likely due to liver injury and not immune flares.

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“We are deeply saddened by the death of a patient in our Catalyst 2 trial,” said Spring Bank CEO, Martin Driscoll. “We will continue to work in close collaboration with external experts and our clinical study investigators to provide the care necessary for all study patients and will continue to conduct a series of investigative actions to better understand the unexpected serious adverse events observed in our phase 2b program.”

In addition to stopping development of inarigivir soproxil, the Company announced that it would not pursue any further research efforts in HBV. 

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