SCHEDULE 13D

CUSIP Number(s):

44975P103

Name of reporting person

HHLR Advisors, Ltd.

Check the appropriate box if a member of a Group (See Instructions)

(a)

(b)

SEC use only

Source of funds (See Instructions)

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

Checkbox not checked

Citizenship or place of organization

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 13,295,306.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 13,295,306.00

Aggregate amount beneficially owned by each reporting person

13,295,306.00

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

Checkbox not checked

Percent of class represented by amount in Row (11)

4.9 %

Type of Reporting Person (See Instructions)

Comment for Type of Reporting Person:

Consists of 5,780,568 ADSs representing 13,295,306 Ordinary Shares held by funds managed by HHLR. HHLR and HIM are under common control and share certain policies, personnel and resources.

SCHEDULE 13D

CUSIP Number(s):

44975P103

Name of reporting person

Hillhouse Investment Management, Ltd.

Check the appropriate box if a member of a Group (See Instructions)

(a)

(b)

SEC use only

Source of funds (See Instructions)

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

Checkbox not checked

Citizenship or place of organization

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 13,295,306.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 13,295,306.00

Aggregate amount beneficially owned by each reporting person

13,295,306.00

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

Checkbox not checked

Percent of class represented by amount in Row (11)

4.9 %

Type of Reporting Person (See Instructions)

Comment for Type of Reporting Person:

Consists of 5,780,568 ADSs representing 13,295,306 Ordinary Shares held by funds managed by HHLR. HHLR and HIM are under common control and share certain policies, personnel and resources.

SCHEDULE 13D

Item 1.

Security and Issuer

(a)

Title of Class of Securities:

Ordinary Shares, par value $0.0001 per share

(b)

Name of Issuer:

NovaBridge Biosciences

(c)

Address of Issuer's Principal Executive Offices:

SUITE 400, 2440 RESEARCH BLVD, ROCKVILLE, MARYLAND , 20850.

Item 1 Comment:

This Amendment No. 6 ("Amendment No. 6") amends the statement on Schedule 13D filed with the Securities and Exchange Commission (the "SEC") on September 14, 2020, as amended by Amendment No. 1 filed on December 21, 2021 with the SEC, Amendment No. 2 filed on March 25, 2021 with the SEC, Amendment No. 3 filed on June 24, 2021 with the SEC, Amendment No. 4 filed on September 27, 2021 with the SEC, Amendment No. 5 filed on June 30, 2023 with the SEC, and as amended hereby (the "Schedule 13D"), with respect to the ordinary shares, par value $0.0001 per share (the "Ordinary Shares") of NovaBridge Biosciences (f/k/a I-MAB), an exempted Cayman Islands company (the "Issuer"). Capitalized terms used herein and not otherwise defined in this Amendment No. 6 have the meanings set forth in the Schedule 13D. This Amendment No. 6 amends Items 5(a)-(c) and (e) as set forth below. This Amendment No. 6 is the final amendment to the Schedule 13D and constitutes an "exit filing" for each of the Reporting Persons. There is no CUSIP number assigned to the Ordinary Shares. CUSIP number 44975P103 has been assigned to the American Depositary Shares ("ADSs") of the Issuer, which are quoted on the Nasdaq Global Market under the symbol "NBP." Each 10 ADSs represents 23 Ordinary Shares.

Item 2.

Identity and Background

(a)

See rows (11) and (13) of the cover pages to this Schedule 13D for the aggregate number of Ordinary Shares and percentages of the Ordinary Shares beneficially owned by each Reporting Person. The percentage used in this Schedule 13D is calculated based upon 270,740,383 Ordinary Shares outstanding as of July 27, 2026, as reported in the Issuer's Report of Foreign Private Issuer on Form 6-K filed with the SEC on September 8, 2026.

(b)

See rows (7) through (10) of the cover pages to this Schedule 13D for the number of Ordinary Shares as to which each Reporting Person has the sole or shared power to vote or direct the vote and sole or shared power to dispose or to direct the disposition.

(c)

Information concerning transactions in the Ordinary Shares (which were in the form of ADS) effected by the Reporting Persons in the last 60 days is set forth in Annex A hereto and is incorporated herein by reference.

(d)

November 5, 2026

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

HHLR Advisors, Ltd.

Signature:	/s/ Audrey Woon
Name/Title:	Audrey Woon, Chief Compliance Officer
Date:	11/05/2026

Hillhouse Investment Management, Ltd.

Signature:	/s/ Audrey Woon
Name/Title:	Audrey Woon, Chief Compliance Officer
Date:	11/05/2026