As filed with the U.S. Securities and Exchange Commission on January 21, 2026

Registration No. 333-292331

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

____________________________

AMENDMENT NO. 2 TO FORM S-1
REGISTRATION STATEMENT
UNDER
THE SECURITIES ACT OF 1933

____________________________

ESTRELLA IMMUNOPHARMA, INC.
(Exact Name of Registrants as Specified in its Charter)

____________________________

Delaware		6770		86-1314502
(State or other jurisdiction of incorporation or organization)		(Primary Standard Industrial Classification Code Number)		(I.R.S. Employer Identification No.)

5858 Horton Street, Suite 370
Emeryville, California, 94608
Telephone: (510) 318-9098
(Address, Including Zip Code, and Telephone Number, Including Area Code, of Registrant’s Principal Executive Offices)

____________________________

Cheng Liu
Chief Executive Officer
5858 Horton Street, Suite 370
Emeryville, California, 94608
Telephone: (510) 318-9098
(Name, Address, Including Zip Code, and Telephone Number, Including Area Code, of Agent for Service)

____________________________

Copies to:

Michael J. Blankenship
Winston & Strawn LLP
800 Capitol Street, Suite 2400
Houston, TX 77002-2925
Telephone: (713) 651-2600

____________________________

Approximate date of commencement of proposed sale to public:
From time to time after the effective date hereof.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box. ☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Large accelerated filer	☐	Accelerated filer	☐
Non-accelerated filer	☒	Smaller reporting company	☒
		Emerging growth company	☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended, or until the registration statement shall become effective on such date as the Commission, acting pursuant to Section 8(a), may determine.

EXPLANATORY NOTE

This Amendment No. 2 (the “Amendment”) to the registration statement on Form S-1 (File No. 333-292331) is being filed as an exhibits-only filing. Accordingly, this Amendment consists only of the facing page, this explanatory note, Item 16(a) of Part II of the Registration Statement, the signature page to the Registration Statement and the filed exhibit. The remainder of the Registration Statement is unchanged and has therefore been omitted.

PART II — INFORMATION NOT REQUIRED IN PROSPECTUS

Item 16. Exhibits

The following is a list of exhibits filed as a part of this registration statement:

(a) Exhibits

Exhibit Number		Description of Exhibit
2.1*		Agreement and Plan of Merger, dated as of September 30, 2022, by and among TradeUP Acquisition Corp., Tradeup Merger Sub Inc. and Estrella Immunopharma, Inc. (incorporated by reference to Exhibit 2.1 to the Current Report on Form 8-K filed with the SEC on October 3, 2022, File No. 001-40608)
3.1		Amended and Restated Certificate of Incorporation of Estrella Immunopharma, Inc. (incorporated by reference to Exhibit 3.1 to the Company’s Current Report on Form 8-K filed with the SEC on October 5, 2023, File No. 001-40608)
3.2		Amended and Restated Bylaws of Estrella Immunopharma, Inc. (incorporated by reference to Exhibit 3.2 to the Company’s Current Report on Form 8-K filed with the SEC on October 5, 2023, File No. 001-40608)
4.1		Specimen Unit Certificate (incorporated by reference to Exhibit 4.1 to Amendment No. 9 to the Registration Statement on Form S-1/A filed with the SEC on July 9, 2021, File No. 333-253322)
4.2		Specimen Common Stock Certificate. (incorporated by reference to Exhibit 4.2 to Amendment No. 9 to the Registration Statement on Form S-1/A filed with the SEC on July 9, 2021, File No. 333-253322)
4.3		Specimen Warrant Certificate (included as Exhibit A to Exhibit 4.4 below)
4.4		Warrant Agreement, dated July 14, 2021, between TradeUP Acquisition Corp. and VStock Transfer, LLC, as warrant agent (incorporated by reference to Exhibit 4.1 to the Current Report on Form 8-K filed with the SEC on July 19, 2021, File No. 001-40608)
4.5		Description of Registrant’s Securities (incorporated by reference to Exhibit 4.5 to the Annual Report on Form 10-K filed with the SEC on September 27, 2024)
5.1		Opinion of Winston & Strawn LLP
10.1		Promissory Note, dated July 25, 2022, issued by TradeUP Acquisition Corp. to Running Lion Holdings Limited (incorporated by reference to Exhibit 10.1 to the Current Report on Form 8-K filed with the SEC on July 27, 2022, File No. 001-40608)
10.2		Promissory Note, dated July 25, 2022, issued by TradeUP Acquisition Corp. to Tradeup INC. (incorporated by reference to Exhibit 10.2 to the Current Report on Form 8-K filed with the SEC on July 27, 2022, File No. 001-40608)
10.3		Contribution Agreement, dated June 28, 2022, by and between Eureka Therapeutics, Inc. and Estrella Immunopharma, Inc. incorporated by reference to Exhibit 10.3 to the registration statement on Form S-4/A filed with the SEC on July 7, 2023 (File No. 333-267918)
10.4†		License Agreement, dated June 28, 2022, by and among Eureka Therapeutics, Inc., Eureka Therapeutics (Cayman) Ltd. and Estrella Immunopharma, Inc. incorporated by reference to Exhibit 10.4 to the registration statement on Form S-4/A filed with the SEC on July 7, 2023 (File No. 333-267918)
10.5†		Services Agreement, dated June 28, 2022, by and between Eureka Therapeutics, Inc. and Estrella Immunopharma, Inc. incorporated by reference to Exhibit 10.5 to the registration statement on Form S-4/A filed with the SEC on July 7, 2023 (File No. 333-267918)
10.6†		Collaboration Agreement, dated October 29, 2021, by and between Estrella Immunopharma, Inc. (as successor to Eureka Therapeutics, Inc.) and Imugene Limited incorporated by reference to Exhibit 10.6 to the registration statement on Form S-4/A filed with the SEC on July 7, 2023 (File No. 333-267918)
10.7		Amendment to Executive Offer Letter, by and between Estrella Immunopharma, Inc. and Dr. Cheng Liu incorporated by reference to Exhibit 10.16 to the Current Report on Form 8-K filed with the SEC on October 5, 2023
10.8		Amendment to Employment Agreement, by and between Estrella Immunopharma, Inc. and Jiandong (Peter) Xu incorporated by reference to Exhibit 10.17 to the Current Report on Form 8-K filed with the SEC on October 5, 2023
10.9		Amendment to Employment Agreement, by and between Estrella Immunopharma, Inc. and Qian (Vicky) Yang incorporated by reference to Exhibit 10.18 to the Current Report on Form 8-K filed with the SEC on October 5, 2023

II-1

Exhibit Number		Description of Exhibit
10.10*		Support Agreement, dated September 30, 2022, by and among TradeUP Acquisition Corp., Estrella Immunopharma, Inc., TradeUP Acquisition Sponsor LLC, Tradeup INC. and the officers and directors of TradeUP Acquisition Corp. (incorporated by reference to Exhibit 10.1 to the Current Report on Form 8-K filed with the SEC on October 3, 2022, File No. 001-40608)
10.11		Estrella Immunopharma, Inc. 2023 Omnibus Incentive Plan incorporated by reference to Annex C to the registration statement on Form S-4/A filed with the SEC on July 7, 2023 (File No. 333-267918)
10.12		Estrella Immunopharma, Inc. Option Grant Notice, including 2022 Equity Incentive Plan incorporated by reference to Exhibit 10.12 to the registration statement on Form S-4/A filed with the SEC on July 7, 2023 (File No. 333-267918)
10.13		Business Combination Marketing Agreement, dated July 14, 2021, among TradeUP Acquisition Corp., US Tiger Securities, Inc. EF Hutton, division of Benchmark Investments, LLC, and R. F. Lafferty & Co., Inc. (incorporated by reference to Exhibit 1.2 to the Current Report on Form 8-K filed with the SEC on July 19, 2021, File No. 001-40608)
10.14		Registration Rights Agreement, dated July 14, 2021, among TradeUP Acquisition Corp., TradeUP Acquisition Sponsor LLC and certain security holders named therein (incorporated by reference to Exhibit 10.3 to the Current Report on Form 8-K filed with the SEC on July 19, 2021, File No. 001-40608)
10.15		Amendment No. 1 to Services Agreement, effective October 1, 2022, by and between Eureka Therapeutics, Inc. and Estrella Immunopharma, Inc. incorporated by reference to Exhibit 10.15 to the registration statement on Form S-4/A filed with the SEC on July 7, 2023 (File No. 333-267918)
10.16		Amendment No. 1 to License Agreement, effective October 1, 2022, by and between Eureka Therapeutics, Inc. and Estrella Immunopharma, Inc. incorporated by reference to Exhibit 10.16 to the registration statement on Form S-4/A filed with the SEC on July 7, 2023 (File No. 333-267918)
10.17		Promissory Note, dated January 19, 2023, issued by TradeUP Acquisition Corp. to TradeUP Acquisition Sponsor LLC (incorporated by reference to Exhibit 10.2 to the Current Report on Form 8-K filed with the SEC on January 24, 2023, File No. 001-40608)
10.18		Extension Promissory Note, dated January 19, 2023, issued by TradeUP Acquisition Corp. to Estrella Immunopharma, Inc. (incorporated by reference to Exhibit 10.1 to the Current Report on Form 8-K filed with the SEC on January 24, 2023, File No. 001-40608)
10.19		Extension Promissory Note, dated February 19, 2023, issued by TradeUP Acquisition Corp. to Estrella Immunopharma, Inc. (incorporated by reference to Exhibit 10.1 to the Current Report on Form 8-K filed with the SEC on February 21, 2023, File No. 001-40608)
10.20		Extension Promissory Note, dated March 17, 2023, issued by TradeUP Acquisition Corp. to Estrella Immunopharma, Inc. (incorporated by reference to Exhibit 10.1 to the Current Report on Form 8-K filed with the SEC on March 17, 2023, File No. 001-40608)
10.21		Extension Promissory Note, dated April 12, 2023, issued by TradeUP Acquisition Corp. to Estrella Immunopharma, Inc. (incorporated by reference to Exhibit 10.1 to the Current Report on Form 8-K filed with the SEC on April 13, 2023, File No. 001-40608)
10.22		Common Stock Purchase Agreement, dated as of April 20, 2023, by and between TradeUP Acquisition Corp. and White Lion Capital LLC (incorporated by reference to Exhibit 10.1 to the Current Report on Form 8-K filed with the SEC on April 24, 2023, File No. 001-40608)
10.23		Registration Rights Agreement, dated as of April 20, 2023, by and between TradeUP Acquisition Corp. and White Lion Capital LLC. (incorporated by reference to Exhibit 10.2 to the Current Report on Form 8-K filed with the SEC on April 24, 2023, File No. 001-40608)
10.24		Amendment to the Common Stock Purchase Agreement, dated as of April 26, 2023, by and between TradeUP Acquisition Corp. and White Lion Capital LLC (incorporated by reference to Exhibit 10.1 to the Current Report on Form 8-K filed with the SEC on April 26, 2023, File No. 001-40608)
10.25		Extension Promissory Note, dated May 19, 2023, issued by TradeUP Acquisition Corp. to Estrella Immunopharma, Inc. (incorporated by reference to Exhibit 10.1 to the Current Report on Form 8-K filed with the SEC on May 19, 2023, File No. 001-40608)
10.26		Promissory Note, dated June 6, 2023, issued by TradeUP Acquisition Corp. to Tradeup INC. (incorporated by reference to Exhibit 10.1 to the Current Report on Form 8-K filed with the SEC on June 6, 2023, File No. 001-40608)

II-2

Exhibit Number		Description of Exhibit
10.27		Amendment No. 2 to Services Agreement, effective March 1, 2023, by and between Eureka Therapeutics, Inc. and Estrella Immunopharma, Inc. incorporated by reference to Exhibit 10.27 to the registration statement on Form S-4/A filed with the SEC on July 7, 2023 (File No. 333-267918)
10.28		Amendment No. 2 to License Agreement, effective March 1, 2023, by and between Eureka Therapeutics, Inc. and Estrella Immunopharma, Inc. incorporated by reference to Exhibit 10.28 to the registration statement on Form S-4/A filed with the SEC on July 7, 2023 (File No. 333-267918)
10.29		Extension Promissory Note, dated June 16, 2023, issued by TradeUP Acquisition Corp. to Estrella Immunopharma, Inc. (incorporated by reference to Exhibit 10.1 to the Current Report on Form 8-K filed with the SEC on June 20, 2023, File No. 001-40608)
10.30		Subscription Agreement dated September 14, 2023 by and among TradeUP Acquisition Corp. and Plentiful Limited (incorporated by reference to Exhibit 10.1 to the Current Report on Form 8-K filed with the SEC on September 20, 2023)
10.31		Subscription Agreement dated September 14, 2023 by and among TradeUP Acquisition Corp. and Lianhe World Limited (incorporated by reference to Exhibit 10.2 to the Current Report on Form 8-K filed with the SEC on September 20, 2023)
10.32		Joinder to the Estrella Series A Purchase Agreement by and between Estrella Biopharma, Inc. and Lianhe World Limited (incorporated by reference to Exhibit 10.4 to the Current Report on Form 8-K filed with the SEC on October 5, 2023)
10.33		Joinder to the Estrella Series A Purchase Agreement by and between Estrella Biopharma, Inc. and CoFame Investments, LLC (incorporated by reference to Exhibit 10.5 to the Current Report on Form 8-K filed with the SEC on October 5, 2023)
10.34		Joinder to the Estrella Series A Purchase Agreement by and between Estrella Biopharma, Inc. and US Tiger Securities, Inc. (incorporated by reference to Exhibit 10.6 to the Current Report on Form 8-K filed with the SEC on October 5, 2023)
10.35		Joinder to the Estrella Series A Purchase Agreement by and between Estrella Biopharma, Inc. and Smart Crest International Limited (incorporated by reference to Exhibit 10.7 to the Current Report on Form 8-K filed with the SEC on October 5, 2023)
10.36		Joinder to the Estrella Series A Purchase Agreement by and between Estrella Biopharma, Inc. and Yangbing Xiao (incorporated by reference to Exhibit 10.8 to the Current Report on Form 8-K filed with the SEC on October 5, 2023)
10.37		Joinder to the Estrella Series A Purchase Agreement by and between Estrella Biopharma, Inc. and Yuandong Wang (incorporated by reference to Exhibit 10.9 to the Current Report on Form 8-K filed with the SEC on October 5, 2023)
10.38		Stock Transfer Agreement by and among Cheng Liu, Jiandong (Peter) Xu and Qian (Vicky) Yang, Yuandong Wang and Estrella Biopharma, Inc. (incorporated by reference to Exhibit 10.10 to the Current Report on Form 8-K filed with the SEC on October 5, 2023)
10.39		Stock Transfer Agreement by and among Cheng Liu, Jiandong (Peter) Xu and Qian (Vicky) Yang, Yangbing Xiao and Estrella Biopharma, Inc. (incorporated by reference to Exhibit 10.11 to the Current Report on Form 8-K filed with the SEC on October 5, 2023)
10.40		Stock Transfer Agreement by and among Cheng Liu, Jiandong (Peter) Xu and Qian (Vicky) Yang, Smart Crest International Limited and Estrella Biopharma, Inc. (incorporated by reference to Exhibit 10.12 to the Current Report on Form 8-K filed with the SEC on October 5, 2023)
10.41		Unsecured Promissory Note by and between Hongbin Zhang and Estrella Biopharma Inc. (incorporated by reference to Exhibit 10.15 to the Current Report on Form 8-K filed with the SEC on October 5, 2023)
10.42		Employment agreement by and between Dr. Cheng Liu and Estrella Immunopharma, Inc. (incorporated by reference to Exhibit 10.19 to the Current Report on Form 8-K filed with the SEC on October 5, 2023)
10.43		Employment Agreement by and between Peter Xu and Estrella Immunopharma, Inc. (incorporated by reference to Exhibit 10.20 to the Current Report on Form 8-K filed with the SEC on October 5, 2023)
10.44		Registration Rights Agreement, dated as of April 20, 2023, by and between TradeUP Acquisition Corp. and White Lion Capital LLC. (incorporated by reference to Exhibit 10.2 to the Current Report on Form 8-K filed with the SEC on April 24, 2023, File No. 001-40608)

II-3

Exhibit Number		Description of Exhibit
10.45		Amendment to the Common Stock Purchase Agreement, dated as of April 26, 2023, by and between TradeUP Acquisition Corp. and White Lion Capital LLC (incorporated by reference to Exhibit 10.1 to the Current Report on Form 8-K filed with the SEC on April 26, 2023, File No. 001-40608)
10.46		Private Placement Shares Purchase Agreement, dated July 14, 2021, among the TradeUP Acquisition Corp., TradeUP Acquisition Sponsor LLC and Tradeup INC. (incorporated by reference to Exhibit 10.4 to the Current Report on Form 8-K filed with the SEC on July 19, 2021)
10.47		Securities Subscription Agreement, between the TradeUP Acquisition Corp. and TradeUP Acquisition Sponsor LLC dated February 12, 2021 (incorporated by reference to Exhibit 10.5 to the Registration Statement on Form S-1 filed with the SEC on July 9, 2021 File No. 333-253322)
10.48		Securities Subscription Agreement, between the TradeUP Acquisition Corp. and Tradeup INC. dated February 12, 2021(incorporated by reference to Exhibit 10.6 to the Registration Statement on Form S-1 filed with the SEC on July 9, 2021 File No. 333-253322)
10.49		Form of Share Purchase Agreement between the TradeUP Acquisition Corp. and the founders (incorporated by reference to Exhibit 10.7 to the Registration Statement on Form S-1 filed with the SEC on June 11, 2021 File No. 333-253322)
10.50		Letter Agreement, dated July 14, 2021, among the TradeUP Acquisition Corp., TradeUP Acquisition Sponsor LLC, Tradeup INC. and certain security holders named therein (incorporated by reference to Exhibit 10.1 to the Current Report on 8-K filed with the SEC on July 19, 2021 File No. 001-40608)
10.51		Statement of Work No. 001, dated and effective as of March 4, 2024, by and among Estrella Biopharma, Inc., Eureka Therapeutics, Inc and Estrella Immunopharma, Inc. (incorporated by reference to Exhibit 10.1 to the Current Report on 8-K filed with the SEC on March 7, 2024, File No. 001-40608)
10.52		Amendment No. 1 to Statement of Work No. 001, dated May 13, 2024 and effective as of March 4, 2024, by and among Estrella Biopharma, Inc., Eureka Therapeutics, Inc. and Estrella Immunopharma, Inc. (incorporated by reference to Exhibit 10.1 to the Current Report on 8-K filed with the SEC on May 13, 2024, File No. 001-40608)
23.1		Consent of Winston & Strawn LLP (included in Exhibit 5.1).
23.2**		Consent of Macias Gini & O’Connell LLP, independent registered public accounting firm to Estrella Immunopharma, Inc.
23.3		Consent of Marcum LLP, former independent registered public accounting firm to Estrella Biopharma, Inc. (now known as Estrella Immunopharma, Inc.)
24.1		Power of Attorney (included on the signature page to this registration statement).
101.INS		Inline XBRL Instance Document.
101.SCH		Inline XBRL Taxonomy Extension Schema Document.
101.CAL		Inline XBRL Taxonomy Extension Calculation Linkbase Document.
101.DEF		Inline XBRL Taxonomy Extension Definition Linkbase Document.
101.LAB		Inline XBRL Taxonomy Extension Label Linkbase Document.
101.PRE		Inline XBRL Taxonomy Extension Presentation Linkbase Document.
104		Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101).
107		Exhibit filing fees

____________

* Annexes, schedules and exhibits have been omitted pursuant to Item 601(b)(2) of Regulation S-K. The registrant agrees to furnish supplementally a copy of any omitted attachment to the Securities and Exchange Commission on a confidential basis upon request.

** Filed herewith.

+ Indicates management contract or compensatory plan.

† Portions of this exhibit (indicated by asterisks) have been omitted because the registrant has determined that the information is both not material and is the type that the registrant treats as private or confidential.

II-4

Signatures

Pursuant to the requirements of the Securities Act, the registrant has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Emeryville, California, on January 21, 2026.

		ESTRELLA IMMUNOPHARMA, INC.
		By:		/s/ Cheng Liu
		Name:		Cheng Liu
		Title:		Chief Executive Officer

Pursuant to the requirements of the Securities Act, this registration statement has been signed below by the following persons in the capacities and on the dates indicated.

Signature	Title	Date
/s/ Cheng Liu	Chief Executive Officer	January 21, 2026
Cheng Liu	(Principal Executive Officer)
*	Chief Financial Officer	January 21, 2026
Peter Xu	(Principal Financial and Accounting Officer)
*	Director	January 21, 2026
Marsha Roberts
*	Director	January 21, 2026
Fan Wu
*	Director	January 21, 2026
Janelle Wu
*	Director	January 21, 2026
Pei Xu
*	Director and Chairperson of the Board	January 21, 2026
Hong Zhang
*	Director	January 21, 2026
Dengyao Jia

Signed by Cheng Liu pursuant to the power of attorney signed by each individual and previously filed with this Registration Statement on December 22, 2025

II-5

Estrella Immunopharma, Inc. S-1/A