A Biotech Startup Just Raised $120 Million Chasing Something No Hepatitis B Drug Has Ever Achieved: An Actual Cure

Most hepatitis B treatments do the same basic thing: they suppress the virus, indefinitely, for as long as a patient keeps taking them. AusperBio is betting $120 million that it can do something different — cure it outright.

The San Francisco-based biopharmaceutical company announced Thursday it has closed a $120 million Series C funding round, bringing its total capital raised since 2024 to $360 million. The round was led by an undisclosed strategic investor, with new participant RA Capital Management joining a group of existing backers that includes HanKang Capital, Qiming Venture Partners, and CDH Investments.

The money is earmarked almost entirely for one program: AHB-137, AusperBio's lead drug candidate and an antisense oligonucleotide therapy — a class of drug designed to interrupt a virus's genetic instructions rather than simply blocking its effects. AHB-137 is built to suppress hepatitis B surface antigen production, inhibit the virus's DNA replication, and reactivate the immune system's own response, with the ultimate goal of achieving what's called a "functional cure" — something current hepatitis B treatments, which mostly just keep the virus suppressed for life, don't offer.

The drug has already cleared a global Phase 1 trial and multiple Phase 2 studies, and it's currently in a Phase 3 registrational trial in China — the stage immediately before a company can seek regulatory approval to actually sell the drug commercially. This funding round is specifically meant to carry that Phase 3 program through to completion and prepare the company for commercial launch if approval comes through.

The scale of the problem AusperBio is targeting is genuinely enormous. According to World Health Organization figures cited in the company's announcement, chronic hepatitis B affects an estimated 254 million people worldwide and causes roughly 1.1 million deaths annually, primarily from cirrhosis and liver cancer — making it one of the largest unmet needs in infectious disease treatment globally, even though it rarely dominates headlines the way other viral diseases do.

Beyond AHB-137, the new funding will also accelerate a second candidate, AHB-171 — an investigational siRNA therapy built on AusperBio's proprietary Au-HALO delivery platform, designed to target liver cells specifically. The company says it also plans to explore combination approaches pairing multiple therapies together, along with broader expansion of its oligonucleotide drug pipeline beyond hepatitis B entirely.

It's worth being precise about where things actually stand: AHB-137 remains an investigational drug. It hasn't been approved by any regulatory authority, and a Phase 3 trial reaching completion doesn't guarantee eventual approval or commercial success. But for a disease that's affected hundreds of millions of people for decades without a genuine cure on the market, a well-funded biotech company pushing a functional-cure candidate through late-stage trials represents a meaningful step — one investors are clearly willing to bet substantially on, given AusperBio's total raise now standing at $360 million in under two years.

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