Pomegra
AusperBio raised $120 million in Series C financing to push its antisense oligonucleotide AHB-137 toward commercialization, bringing total capital to $360 million since 2024.
- AusperBio closed a $120M Series C on August 27, 2026, led by an undisclosed strategic investor with RA Capital Management joining as a new backer.
- Lead candidate AHB-137 is in a Phase III registrational trial (AUSHINE) in China, with 570+ patients enrolled as of December 2025.
- The San Francisco-based company targets a functional cure for chronic hepatitis B, a disease affecting an estimated 296 million people globally with limited curative options.
Lead
AusperBio Therapeutics, the San Francisco-based biotech developing oligonucleotide therapies for chronic hepatitis B, closed a $120 million Series C on August 27, 2026. The round was led by an undisclosed strategic investor, with RA Capital Management joining as a new financial backer. Existing investors - including HanKang Capital, Sherpa Capital, Qiming Venture Partners, CDH Investments, InnoPinnacle Fund, and YuanBio Venture Capital - returned for the round. The raise brings AusperBio's cumulative capital to $360 million since the company's founding in 2024.
What Is AusperBio Actually Building?
The company's lead asset, AHB-137, is an unconjugated antisense oligonucleotide built on AusperBio's proprietary Med-Oligo technology platform. Unlike most marketed hepatitis B antivirals, which suppress viral replication but require lifelong dosing, AHB-137 is engineered to work on three fronts simultaneously: suppressing hepatitis B surface antigen (HBsAg) at the transcriptional level, inhibiting viral DNA replication, and promoting immune reactivation.
The goal is a functional cure - defined in hepatitis B research as sustained HBsAg loss after treatment stops, the closest achievable proxy to eradication in patients with established chronic infection.
Why Does This Round Signal Strategic Momentum?
AusperBio raised a $50 million Series B+ in 2025 and followed it within months with a $63 million Series B2. The Series C at $120 million represents the largest single tranche to date and arrives alongside a clinical milestone that matters: the Phase III AUSHINE trial completed enrollment of more than 570 patients in December 2025, within five months of receiving clearance from China's Center for Drug Evaluation. That pace is unusually fast for a large Phase III.
The participation of RA Capital Management, a life sciences specialist with a track record of backing late-stage clinical programs, is notable. RA Capital typically enters positions where it sees a credible path to registration within a defined horizon, adding a signal about Phase III confidence that the company's own press language cannot.
Valuation was not disclosed.
How Crowded Is the Functional Cure Space?
Chronic hepatitis B has historically been one of the more resistant targets in antiviral development. Nucleos(t)ide analogues like tenofovir and entecavir suppress the virus effectively but deliver HBsAg loss rates below 10% over five years of treatment. Several companies, including large-cap pharma players, have pursued combinations of RNA interference agents, capsid assembly modulators, and immunomodulators with mixed results. No product has reached registration with a functional cure label.
AHB-137's differentiation, if Phase III data hold, rests on its unconjugated ASO design - avoiding the GalNAc conjugation that competing ASOs typically require to achieve hepatic uptake - and its single-agent immune reactivation mechanism. Whether this translates to superior HBsAg loss rates in a 570-patient confirmatory trial is the open question the AUSHINE readout will need to answer.
What the Capital Will Fund
Proceeds from the Series C are earmarked to advance AHB-137 toward Phase III completion and commercial readiness, and to expand AusperBio's pipeline of next-generation HBV therapies. The company has not disclosed a regulatory submission timeline or a specific AUSHINE primary endpoint readout date.
The dual structure - U.S.-based AusperBio Therapeutics and China-based Ausper Biopharma - positions the company to pursue registration in both markets. The AUSHINE trial is currently enrolling in China; a global strategy has not been formally announced.
Outlook
AusperBio enters its most consequential phase - Phase III completion and potential commercial buildout - with $360 million in cumulative backing and a Phase III enrollment already closed ahead of schedule. The critical variable is efficacy: if AUSHINE delivers HBsAg loss rates that exceed standard-of-care benchmarks at a statistically meaningful level, AHB-137 enters a regulatory review process with limited head-to-head competition in the functional cure category. If the data disappoint, the capital burned building to this point will look expensive against a field where several well-funded predecessors have stalled at the same juncture.
