AusperBio Therapeutics has closed a $120 million Series C, handing the hepatitis B specialist a late-stage war chest as its lead antisense drug moves through a registrational trial in China and the company begins describing itself as "near-commercial."

The San Francisco-based biotech announced the round on August 27, 2026. It was led by an unnamed "leading strategic investor," with new backer RA Capital Management, L.P. joining existing shareholders HanKang Capital, Sherpa Capital, InnoPinnacle Fund, Qiming Venture Partners, YuanBio Venture Capital and CDH Investments. AusperBio says the financing brings its total capital raised to $360 million since 2024. No valuation was disclosed.

What the company does

AusperBio, co-founded by Chief Executive Dr. Guofeng Cheng and Chief Scientific Officer Dr. Chris Yang, builds targeted oligonucleotide therapeutics on a proprietary antisense platform it calls Med-Oligo, paired with a delivery technology branded Au-HALO. The company runs operations in both the United States and China.

Its lead asset, AHB-137, is an investigational antisense oligonucleotide aimed at the single hardest problem in chronic hepatitis B: clearing hepatitis B surface antigen. The drug is designed to suppress HBsAg production, inhibit viral DNA replication and reawaken an immune response that decades of chronic infection have exhausted. The goal is a functional cure rather than the indefinite viral suppression that nucleos(t)ide analogues deliver today. Behind it sits AHB-171, an siRNA candidate that doubles as the first clinical test of the company's targeted delivery platform.

The numbers behind the round

The Series C is comfortably AusperBio's largest raise, and it caps an unusually dense financing run. The company took $73 million in a Series B in December 2024, added $50 million in a Series B+ in May 2025, then $63 million in a Series B2 in September 2025 before this $120 million round — four raises in roughly 20 months. Those disclosed rounds sum to about $306 million, short of the $360 million cumulative figure the company cites, which suggests earlier or unannounced capital sits inside the total.

Two details are worth flagging. The lead investor is not named in any version of the announcement, described only as a strategic backer — the same construction AusperBio used for a co-lead of its Series B2. And RA Capital's arrival is the round's clearest outside signal: the Boston crossover firm typically shows up when a private company is within sight of registrational data or a public listing.

Why the timing matters

The money lands with AHB-137 already deep into a pivotal program. AusperBio completed enrollment in its Phase III AUSHINE study in December 2025, signing up more than 570 HBeAg-negative patients on nucleos(t)ide analogue therapy within five months of Chinese regulatory clearance. The trial is randomized, double-blind and multicenter, registered as CTR20252792 and NCT07246889.

The clinical case rests on mid-stage results that have travelled well. Late-breaking 48-week Phase II data presented at AASLD 2025 showed responses sustained 24 weeks after treatment ended, with a 300 mg, 24-week regimen producing the highest rates and no new safety signals off treatment. Data shown at HEP-DART 2025 pointed to a functional cure rate of roughly 30 percent — a number that, if it holds in Phase III, would be a meaningful step beyond the status quo in a disease affecting close to 300 million people worldwide.

Proceeds will fund the Phase III registrational program and what the company calls commercialization readiness, accelerate AHB-171, and push next-generation combination approaches and a broader oligonucleotide pipeline. That last clause matters: the field increasingly assumes a functional cure will require combinations, and AusperBio is now capitalized to test that thesis itself rather than partner it away.

Source

PR Newswire — "AusperBio Completes $120 Million Series C Financing to Advance AHB-137 Toward Potential Commercialization and Expand Next-Generation HBV Therapies"