Analysis
AusperBio Therapeutics and its affiliate Ausper Biopharma closed a $120 million Series C financing on Aug. 27, led by an unnamed strategic investor with new participation from RA Capital Management, one of biotech's more selective specialist funds. The round brings AusperBio's total capital raised since 2024 to $360 million and will fund its lead asset, AHB-137, through a Phase 3 registrational program for chronic hepatitis B and toward commercialization readiness, BioSpace reported.
AusperBio is headquartered in San Francisco with research and development operations in China, and existing backers HanKang Capital, Sherpa Capital, InnoPinnacle Fund, Qiming Venture Partners, YuanBio Venture Capital and CDH Investments all returned for the Series C alongside RA Capital's new commitment.
What the drug does
AHB-137 is an antisense oligonucleotide, or ASO, therapy designed to reduce the viral proteins that let hepatitis B persist in the liver and evade the immune system. Chronic hepatitis B affects an estimated 250 million people worldwide, and existing antivirals suppress the virus without curing it -- patients typically stay on therapy indefinitely. A functional cure, meaning sustained viral suppression after stopping treatment, remains the industry's holy grail, and AHB-137 reaching Phase 3 puts AusperBio among a small group of companies with a late-stage HBV cure candidate. The financing will also advance AHB-171, a second candidate using RNA interference built on AusperBio's proprietary Au-HALO targeted delivery platform, aimed at combination regimens.
The competitive landscape
- AusperBio -- $120M Series C, $360M total: ASO therapy AHB-137 in Phase 3 for chronic hepatitis B, plus siRNA candidate AHB-171. Competitors: Gilead Sciences, Arbutus Biopharma, Vir Biotechnology, Assembly Biosciences, all running competing HBV cure-track programs. Source
Gilead and Vir have the deepest pockets and longest HBV pipelines; Arbutus and Assembly are more direct scale peers to AusperBio in stage and financing profile. A Phase 3 asset with $360 million in cumulative backing and a strategic investor willing to lead puts AusperBio ahead of most of that cohort on capital, though not yet on regulatory proof.
The counterweight
Phase 3 is where HBV cure programs have historically stumbled -- durability of response after treatment withdrawal is the metric regulators care about most, and it takes years of follow-up to demonstrate. A $120 million round funds trial execution, not necessarily approval, and AusperBio's unnamed strategic lead investor withholding its name is worth noting; strategics that stay anonymous at this stage are sometimes hedging their own confidence in the asset. The China R&D footprint also means any cross-border IP or data-sharing friction is a real operational risk as US-China biotech ties tighten, and any future export-control or investment-screening action targeting cross-border biotech financing would land directly on AusperBio's cap table structure.
Founded to commercialize antisense technology out of a research pipeline built for the Chinese and US markets simultaneously, AusperBio has scaled headcount alongside its raises without disclosing exact employee counts, a common pattern for clinical-stage biotechs that keep commercial infrastructure lean until a pivotal readout de-risks the program.
The $360 million raised to date compares to the roughly $500 million to $1 billion typically required to bring a novel HBV therapy from Phase 3 through approval, meaning this round buys AusperBio real runway but likely not the full path to a launch without at least one more financing.
