Following Patient Death, Spring Bank Abandons Hepatitis B Program

 

Spring Bank Pharmaceuticals, based in Hopkinton, Massachusetts, announced it was discontinuing development of inarigivir soproxil for chronic hepatitis B virus (HBV). The therapy was in Phase II development.

The company based the decision on safety information after unexpected serious adverse events, including one patient death in its Phase IIb CATALYST trial. Inarigivir is an orally available immunomodulator that binds the cellular proteins retinoic acid-inducible gene 1 (RIG-1) to inhibit viral replication and induce the intracellular interferon signaling pathways.

“We are deeply saddened by the death of a patient in our CATALYST 2 trial,” said Martin Driscoll, president and chief executive officer of Spring Bank. “Because we are guided by an overriding interest in protecting patients, we have made the difficult decision to discontinue the further development of inarigivir for the treatment of HBV at Spring Bank. 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 IIb program.”

On December 26, 2019, the company indicated it had halted dosing and enrolling patients in the CATALYST trial as well as all other studies of inarigivir in chronic HBV. Lab tests from three patients showed hepatocellular dysfunction and an increased alanine transaminase (ALT) level consistent with liver injury.

It essentially plans to abandon R&D into HBV but will refocus on immuno-oncology and inflammation. This is primarily its lead product candidate from its STING agonist platform, SB 11285, which is in a Phase Ia/Ib trial.

On November 20, 2019, Spring Bank announced it had begun dosing patients in the Phase I trial of SB 11285 in patients with advanced solid tumors. Part 1 of the trial is a dose-escalation study with SB 11285 alone. It will be followed by a combination with a checkpoint inhibitor. Part 2 of the trial will evaluate intravenous SB 11285 antitumor activity in combination with a checkpoint inhibitor in various tumor types. The company hopes to report topline data in mid-2020.

“Working with our principal investigators in the United States, we are thrilled to announce that we have been able to deliver SB 11285 intravenously to the first patient in our Phase I trial of advanced solid tumors,” said Atif Abbas, vice president and head of Oncology/Immunology Development at Spring Bank, at the time.

He went on to say, “We believe the primary benefit of delivering SB 11285 by the intravenous route, as opposed to intratumorally like other STING agonist compounds currently in development, is the potential ability to treat a broader range of cancers and patients in the community oncology treatment setting.”

Now that Spring Bank is halting all HBV drug development, it is launching talks with external parties to license the program. And by eliminating the costs related to the HBV program, it believes it has funds to continue operations into late 2022. As of December 31, 2019, the company reported $54.5 million in cash.