UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16 UNDER

THE SECURITIES EXCHANGE ACT OF 1934

For the month of December 2025

Commission File Number: 001-39173

NovaBridge Biosciences

2440 Research Boulevard, Suite 400

Rockville, MD 20850

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F ☒                Form 40-F ☐

On December 3, 2025, the Company issued a press release, a copy of which is furnished herewith as Exhibit 99.1 to this report.

EXHIBIT INDEX

Exhibit No.	Description
99.1	Press Release - NovaBridge Announces Presentation of Ragistomig Expanded Phase 1 Data at ESMO IO

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.

I-MAB
By	:	/s/ Xi-Yong Fu
Name	:	Xi-Yong (Sean) Fu
Title	:	Chief Executive Officer

Date: December 4, 2025