Assembly Biosciences Strengthens Pipeline and Balance Sheet After $115M Upsized Raise

Assembly Biosciences has emerged from the EASL Congress in Barcelona with more than just data. The biotech firm capped a $115 million capital increase by unveiling plans to take its lead oral candidate ABI-6250 into two new rare liver diseases, while a key partnership with Gilead Sciences inches toward a major commitment.

The follow-on offering, initially pegged at $100 million, was upsized after underwriters fully exercised their greenshoe option. A total of 3,924,624 shares sold at $26.50 apiece, including 566,040 additional shares from the overallotment. Alongside the common stock, the company issued pre-funded warrants for up to 415,000 shares at $26.499 each — essentially the offering price minus a nominal $0.001 exercise price — to an existing investor. Net proceeds stand at roughly $107.4 million after fees and expenses, earmarked for clinical development of its viral and liver disease pipeline and general corporate purposes.

The capital arrives as Assembly Bio pushes ABI-6250, an oral NTCP receptor inhibitor, beyond hepatitis delta. Phase 1a data presented at EASL, led by Dr. Edward J. Gane, showed a safety and activity profile that management deems sufficient to advance into Phase 2. The company plans to launch a Phase 2 study in chronic HDV patients in the fourth quarter of 2026. More striking is the drug’s expanded potential: because NTCP also transports bile acids into liver cells, Assembly Bio intends to test ABI-6250 in primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) — both characterized by bile acid accumulation and liver inflammation. Following a pre-IND meeting with the FDA, a Phase 2 basket study for both indications is slated for the first quarter of 2027.

Should investors sell immediately? Or is it worth buying Assembly Biosciences?

Meanwhile, the herpesvirus program, run with Gilead Sciences, is nearing a critical juncture. Phase 1b studies for two helicase-primase inhibitors, ABI-5366 and ABI-1179, targeting recurrent genital herpes, have wrapped up. Gilead has already exercised its option to license the program, and by mid-2026 Assembly Bio must decide whether to co-fund 40% of U.S. costs and share in U.S. profits, pending Gilead’s formal development plan.

Pro-forma cash and equivalents now stand at approximately $226.6 million, providing runway through 2028. The share price sits at $27.40, just above the offering’s $26.50 price but roughly 29% below the 52-week high of $38.50. Still, the stock has nearly doubled over the past year, reflecting the broader context for a capital raise executed at a relatively favorable window.

With fresh cash, validated early data, and a broadened indication set, Assembly Bio has used its Barcelona platform to reposition itself as a multi-indication liver disease player — and to give investors a clearer picture of what the next 18 months might deliver.