UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
FORM
CURRENT REPORT
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Item 7.01 Regulation FD Disclosure.
On August 8, 2025, Assembly Biosciences, Inc. (the “Company”) issued a press release announcing interim results from the Phase 1b portion of its ongoing Phase 1a/b clinical study evaluating ABI-5366, an investigational long-acting herpes simplex virus (“HSV”) helicase-primase inhibitor candidate for recurrent genital herpes (the “ABI-5366 Study”). A copy of the press release is attached as Exhibit 99.1 and is incorporated herein by reference.
The information in this Item 7.01 is being furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that Section, nor shall it be deemed incorporated by reference into any registration statement or other filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such filing.
Item 8.01 Other Events.
The Company announced interim results from the ABI-5366 Study. For the powered antiviral endpoint, HSV type 2 (“HSV-2”) shedding rate, highly potent antiviral activity was observed with a 94% reduction compared to placebo (p<0.01) over the 29-day evaluation period in the cohort evaluating a 350 mg weekly dose. This reduction exceeds our target for the study of an 80%-85% reduction in the rate of HSV-2 shedding.
For a secondary clinical endpoint of genital lesion rate, a 94% reduction compared to placebo (p<0.01) was observed with the 350 mg weekly dose. The rate of samples with high viral load (i.e., >104 copies/mL HSV DNA), a potential surrogate for HSV-2 transmission and a secondary endpoint, was reduced by 98% compared to placebo (p<0.05) in this cohort.
ABI-5366 was observed to be well-tolerated at oral doses up to 350 mg weekly in participants seropositive for HSV-2 with recurrent genital herpes. The observed pharmacokinetic profile continues to support once-weekly dosing and the potential for once-monthly oral dosing regimens. With these data, the Company expects to move directly into Phase 2 clinical study preparation in parallel with completion of this Phase 1b study, which includes an ongoing cohort evaluating a monthly oral dosing regimen. The in-life portions of chronic toxicology studies of ABI-5366 are now complete and these studies are expected to support longer-term dosing in Phase 2.
Item 9.01 Financial Statements and Exhibits.
(d) Exhibits.
| Exhibit Number |
Description | |
| 99.1 | Press Release dated August 8, 2025. | |
| 104 | Cover Page Interactive Data File (embedded within the Inline XBRL document). | |
SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.
| Assembly Biosciences, Inc. | ||||||
| Date: August 8, 2025 | By: | /s/ John O. Gunderson | ||||
| John O. Gunderson | ||||||
| VP, General Counsel and Corporate Secretary | ||||||