Aligos culls another hepatitis B asset, citing inconclusive efficacy data

Strike another hepatitis B drug candidate from Aligos Therapeutics’ once-stacked pipeline. The biotech kept up the cadence of program pruning by deciding against committing more cash to an siRNA prospect after getting a look at early-phase data.

Aligos, which was once focused on developing a functional cure for hepatitis B, shifted its attention to nonalcoholic steatohepatitis (NASH) and COVID-19 in February. The biotech decided to continue phase 1 clinical trials of its two remaining hepatitis B candidates but prioritize investment in NASH and COVID-19 to get prospects past milestones. 

The earlier update indicated that ALG-125755, a siRNA that targets the production of hepatitis B surface antigen (HBsAg), was unlikely to have a future at Aligos. The biotech confirmed that indication in its update on the second quarter.

In the statement, Aligos said dosing in the first two parts of its ALG-125755 study is now complete, giving the biotech data on the use of single ascending subcutaneous doses of the siRNA candidate in healthy volunteers and virologically suppressed, hepatitis B e-antigen-negative subjects with chronic hepatitis B. 

The early-phase study found ALG-125755 was well tolerated. Pharmacokinetic results matched Aligos’ predictions, and the candidate lowered HBsAg levels across the dose range evaluated. However, with the comparative efficacy data versus rival siRNAs proving “inconclusive,” Aligos will only advance the asset if a partner comes on board. The biotech is saving its dwindling internal resources for other programs. 

Aligos continues to collect clinical data on its capsid-assembly modulator, ALG-000184, but that is now its only hepatitis B program in active development. The biotech dropped two drug candidates early last year in response to lackluster efficacy and a safety signal.

Retreating from hepatitis B will allow Aligos to pump its remaining $90.8 million into other indications. The biotech expects the money to keep the lights on until the end of next year, by which time it could have phase 1 data on its COVID-19 candidate and results from a phase 2 trial of its NASH prospect. Aligos is cutting it fine with the NASH program, with data due in the fourth quarter of 2024.