Assembly Biosciences Secures $100M Capital Infusion to Expand ABI-6250 Beyond Hepatitis Delta

Assembly Biosciences raises $100M, including Gilead, to expand ABI-6250 beyond hepatitis delta into PBC and PSC; stock rises 6.94% despite dilution.

Assembly Biosciences is broadening its pipeline ambitions for ABI-6250, moving beyond hepatitis delta into cholestatic liver diseases, backed by a $100 million capital raise that included participation from Gilead Sciences. The oral NTCP inhibitor, originally focused on chronic hepatitis delta virus infections, will now be evaluated in primary biliary cholangitis and primary sclerosing chololangitis—two conditions with limited therapeutic options and significant unmet need.

The equity offering involved 3.36 million common shares at $26.50 each, plus pre-funded warrants for 415,000 shares. Underwriters Guggenheim Securities, UBS Investment Bank and Mizuho have a 30-day option for up to 566,040 additional shares at the same price. Despite the dilution, shares climbed 6.94% to close at $28.34 on Friday, reflecting investor confidence in the extended cash runway. Year-to-date, the stock remains down 16.02%, though it has surged 109% over the past twelve months. The relative strength index of 28.6 signals oversold territory.

Assembly ended the first quarter with $226.6 million in cash, and the new funding is expected to sustain operations into 2028. The financing round drew commitments from Gilead Sciences, Commodore Capital, Farallon Capital Management and other healthcare-focused funds. The cash cushion is critical for a biotech navigating mid-stage clinical programs, where delays due to insufficient capital can derail promising assets.

ABI-6250 works by blocking the NTCP receptor, preventing the entry of bile acids and viruses into liver cells—a mechanism that addresses both viral hepatitis and cholestatic inflammation. Completed chronic toxicology studies and a Phase 1a trial provide the underpinning for the expanded indications. The clinical calendar is now set: a Phase 2 study for hepatitis delta is slated to begin in the fourth quarter of 2026, followed by a Phase 2 basket trial for PBC and PSC in the first quarter of 2027.

The next immediate catalyst comes at the EASL congress in Barcelona (May 27–30), where Assembly will present topline safety and pharmacokinetic data from the Phase 1a study of ABI-6250. Those results will offer the first detailed look at the molecule’s profile and could either validate or challenge the expansion strategy.

Beyond ABI-6250, another inflection point arrives by mid-2026, when Gilead is expected to issue a development plan for the herpesvirus programs ABI-5366 and ABI-1179. Assembly must then decide whether to enter into a U.S. agreement carrying a 40% cost and profit share. Meanwhile, Gilead declined to exercise its option for the hepatitis B candidate ABI-4334 in March 2026, returning full rights to Assembly. The company is now searching for a new partner to advance that program.

Analyst consensus on the stock is “Buy” with a price target of $50, more than 75% above the current level. The capital raise introduces near-term dilution, but it buys time for the pipeline to generate data. The market’s next test will be whether ABI-6250 can deliver safety and pharmacokinetic results convincing enough to justify the multiple trials now planned—and whether the broader story can outrun the lingering technical weakness in the share price.