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SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Name of Issuer)

(Title of Class of Securities)

(CUSIP Number)

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

SCHEDULE 13D/A 0002010692 XXXXXXXX LIVE 1 Common Stock 08/15/2025 true 0001604464 046513107 Atara Biotherapeutics, Inc. 1280 Rancho Conejo Blvd Thousand Oaks CA 91320 James Huang (86-21) 6176-1101 Panacea Venture No. 5, Lane 1350, Fuxing Middle Road Xuhui District, Shanghai F4 200031 0002010692 N Panacea Innovation Limited OO N E9 0 1712900 0 1712900 1712900 N 20.0 CO Includes 307,900 warrants to purchase Common Stock. The warrants are immediately exercisable and do not expire. No portion of the warrants beneficially owned by the Reporting Persons may be exercised to the extent that, after giving effect to the attempted exercise, the Reporting Persons would beneficially own in excess of 19.99% of the outstanding Common Stock. Based on 7,023,032 shares of Common Stock outstanding as of August 6, 2025, the Reporting Persons may not exercise any warrants currently. 0001869939 N Panacea Venture Healthcare Fund II, L.P. OO N E9 0 1405000 0 1405000 1405000 N 20.0 PN Y Panacea Venture Healthcare Fund II GP Company, Ltd. OO N E9 0 1405000 0 1405000 1405000 N 20.0 CO 0001869966 N Panacea Opportunity Fund I, L.P. OO N E9 0 307900 0 307900 307900 N 4.2 PN Includes 307,900 warrants to purchase Common Stock. The warrants are immediately exercisable and do not expire. No portion of the warrants beneficially owned by the Reporting Persons may be exercised to the extent that, after giving effect to the attempted exercise, the Reporting Persons would beneficially own in excess of 19.99% of the outstanding Common Stock. Based on 7,023,032 shares of Common Stock outstanding as of August 6, 2025, the Reporting Persons may not exercise any warrants currently. Y Panacea Opportunity Fund I GP Company, Ltd. OO N E9 0 307900 0 307900 307900 N 4.2 CO Includes 307,900 warrants to purchase Common Stock. The warrants are immediately exercisable and do not expire. No portion of the warrants beneficially owned by the Reporting Persons may be exercised to the extent that, after giving effect to the attempted exercise, the Reporting Persons would beneficially own in excess of 19.99% of the outstanding Common Stock. Based on 7,023,032 shares of Common Stock outstanding as of August 6, 2025, the Reporting Persons may not exercise any warrants currently. 0001573160 N James Huang OO N F4 0 1712900 0 1712900 1712900 N 20.0 IN Includes 307,900 warrants to purchase Common Stock. The warrants are immediately exercisable and do not expire. No portion of the warrants beneficially owned by the Reporting Persons may be exercised to the extent that, after giving effect to the attempted exercise, the Reporting Persons would beneficially own in excess of 19.99% of the outstanding Common Stock. Based on 7,023,032 shares of Common Stock outstanding as of August 6, 2025, the Reporting Persons may not exercise any warrants currently. Common Stock Atara Biotherapeutics, Inc. 1280 Rancho Conejo Blvd Thousand Oaks CA 91320 This Amendment No. 1 to Schedule 13D amends and supplements the statement on Schedule 13D originally filed with the United States Securities and Exchange Commission on May 21, 2025 (as amended, the "Schedule 13D"), relating to the Common Stock. Capitalized terms used herein without definition shall have the meaning set forth in the Schedule 13D. From July 17, 2025 through August 19, 2025, Panacea Venture Healthcare Fund II, L.P. purchased 74,335 shares of Common Stock in a series of open market transactions for aggregate cash consideration of approximately $857,000. Panacea Venture Healthcare Fund II, L.P. obtained the funds used to purchase the Common Stock through capital contributions from their partners. The information contained on the cover pages is incorporated by reference into this Item 5. Panacea Venture Healthcare Fund II, L.P. is the record holder of 1,405,000 shares of Common Stock, and Panacea Opportunity Fund I, L.P. is the record holder of warrants to purchase 307,900 shares of Common Stock. The warrants are immediately exercisable and do not expire. No portion of the warrants beneficially owned by the Reporting Persons may be exercised to the extent that, after giving effect to the attempted exercise, the Reporting Persons would beneficially own in excess of 19.99% of the outstanding Common Stock. James Huang is the sole owner of Panacea Innovation Limited, which is the sole owner of Panacea Venture Healthcare Fund II GP Company, Ltd. and Panacea Opportunity Fund I GP Company, Ltd., which are the general partners of Panacea Venture Healthcare Fund II, L.P. and Panacea Opportunity Fund I, L.P., respectively. As a result, Panacea Venture Healthcare Fund II GP Company, Ltd. and Panacea Opportunity Fund I GP Company, Ltd. may be deemed to share beneficial ownership of the securities held of record by Panacea Venture Healthcare Fund II, L.P. and Panacea Opportunity Fund I, L.P., respectively. Panacea Innovation Limited and Mr. Huang may be deemed to share beneficial ownership of the securities beneficially owned by the foregoing entities, but each disclaims such beneficial ownership. The information contained on the cover pages is incorporated by reference into this Item 5. On July 17, 2025, Panacea Venture Healthcare Fund II, L.P. purchased 19,335 shares of Common Stock at a weighted average price of $9.6391 per share in a series of open market transactions. On August 15, 2025, Panacea Venture Healthcare Fund II, L.P. purchased 55,000 shares of Common Stock at a weighted average price of $12.1895 per share in a series of open market transactions. Except for the transactions disclosed in this Item 5(c), none of the Reporting Persons has effected any transactions in the Common Stock during the past sixty days. None. Not applicable Panacea Innovation Limited /s/ James Huang James Huang, Founding Managing Partner 08/19/2025 Panacea Venture Healthcare Fund II, L.P. By: Panacea Venture Healthcare Fund II GP Company, Ltd., its general partner, By: Panacea Innovation Limited, its sole owner, By: /s/ James Huang James Huang, Founding Managing Partner 08/19/2025 Panacea Venture Healthcare Fund II GP Company, Ltd. By: Panacea Innovation Limited, its sole owner, By: /s/ James Huang James Huang, Founding Managing Partner 08/19/2025 Panacea Opportunity Fund I, L.P. By: Panacea Opportunity Fund I GP Company, Ltd., its general partner, By: Panacea Innovation Limited, its sole owner, By: /s/ James Huang James Huang, Founding Managing Partner 08/19/2025 Panacea Opportunity Fund I GP Company, Ltd. By: Panacea Innovation Limited, its sole owner, By: /s/ James Huang James Huang, Founding Managing Partner 08/19/2025 James Huang /s/ James Huang James Huang 08/19/2025