Panacea Innovation Ltd - 28 Nov 2025 Form 4 Insider Report for Atara Biotherapeutics, Inc. (ATRA)

Role: 10%+ Owner
Signature: Panacea Innovation Limited By: /s/ James Huang, Founding Managing Partner
Issuer symbol: ATRA
Transactions as of: 28 Nov 2025
Net transactions value: -$322,156
Form type: 4
Filing time: 01 Dec 2025, 17:00:04 UTC
Previous filing: 19 Aug 2025
Next filing: 14 Jan 2026
SEC: View on sec.gov

Reporting Owners (2)

Name	Relationship	Address	Signature	Signature date	CIK
Panacea Innovation Ltd	10%+ Owner	C/O MAPLES CORPORATE SERVICES LIMITED,, UGLAND HOUSE, GRAND CAYMAN, CAYMAN ISLANDS	Panacea Innovation Limited By: /s/ James Huang, Founding Managing Partner	01 Dec 2025	0002010692
Huang James	Director, 10%+ Owner	C/O MAPLES CORPORATE SERVICES LIMITED,, UGLAND HOUSE, GRAND CAYMAN, CAYMAN ISLANDS	/s/ James Huang	01 Dec 2025	0001573160

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	ATRA	Common Stock	Options Exercise	$4.87	+48,737		$0.000100	48,737	28 Nov 2025	See Footnotes	F1, F2
transaction	ATRA	Common Stock	Tax liability	$14.03	-1	-0%	$14.03	48,736	28 Nov 2025	See Footnotes	F1, F2
holding	ATRA	Common Stock						1,405,000	28 Nov 2025	See Footnotes	F2, F3

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	ATRA	Warrants	Options Exercise	$322,147	-48,737	-16%	$6.61	259,163	28 Nov 2025	Common Stock	48,737	$0.000100	See Footnotes	F1, F2, F4

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	Represents securities held by Panacea Opportunity Fund I, L.P.
F2	James Huang is the sole owner of Panacea Innovation Limited, which is the sole owner of Panacea Venture Healthcare Fund II GP Company, Ltd. ("Fund II GP") and Panacea Opportunity Fund I GP Company, Ltd. ("Opportunity Fund GP"), which are the general partners of Panacea Venture Healthcare Fund II, L.P. and Panacea Opportunity Fund I, L.P. As a result, each of the Reporting Persons 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., but each disclaims such beneficial ownership.
F3	Represents securities held by Panacea Venture Healthcare Fund II, L.P.
F4	The warrants are immediately exercisable and do not expire. Pursuant to the terms of the warrants, no portion of the warrants held by a holder may be exercised to the extent that, after giving effect to the attempted exercise, such holder, together with such holder's affiliates and any other person whose beneficial ownership of the Issuer's common stock would be aggregated with such holder's for the purposes of Section 13(d) of the Exchange Act, would beneficially own in excess of 19.99% of the outstanding common stock.