# EDGAR Filing Document

**Accession Number:** 0001604464
**File Stem:** 0001193125-26-062534
**Filing Date:** 2026-2
**Character Count:** 85038
**Document Hash:** 856dfd5de75ce21fa06877f4831cba9c
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-26-062534.hdr.sgml**: 20260223

**ACCESSION NUMBER**: 0001193125-26-062534

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 15

**CONFORMED PERIOD OF REPORT**: 20260220

**ITEM INFORMATION**: Entry into a Material Definitive Agreement

**ITEM INFORMATION**: Unregistered Sales of Equity Securities

**ITEM INFORMATION**: Other Events

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20260223

**DATE AS OF CHANGE**: 20260223

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Atara Biotherapeutics, Inc.
- **CENTRAL INDEX KEY:** 0001604464
- **STANDARD INDUSTRIAL CLASSIFICATION:** BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 460920988
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 8-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-36548
- **FILM NUMBER:** 26662171

**BUSINESS ADDRESS:**
- **STREET 1:** 1280 RANCHO CONEJO BLVD
- **CITY:** THOUSAND OAKS
- **STATE:** CA
- **ZIP:** 91320
- **BUSINESS PHONE:** 805-623-4211

**MAIL ADDRESS:**
- **STREET 1:** 1280 RANCHO CONEJO BLVD
- **CITY:** THOUSAND OAKS
- **STATE:** CA
- **ZIP:** 91320

?xml version='1.0' encoding='ASCII'? 8-K

### UNITED STATES

### SECURITIES AND EXCHANGE COMMISSION

#### WASHINGTON, D.C. 20549

### FORM 8-K

#### CURRENT REPORT

#### Pursuant to Section 13 or 15(d)

#### of the Securities Exchange Act of 1934

#### Date of Report (Date of earliest event reported): February 20, 2026

## Atara Biotherapeutics, Inc.

#### (Exact name of Registrant as Specified in Its Charter)

---

| | | |
|:---|:---|:---|
| **Delaware** | **001-36548** | **46-0920988** |
| **(State or Other Jurisdiction**<br> **of Incorporation)** | **(Commission**<br> **File Number)** | **(IRS Employer**<br> **Identification No.)** |

---

---

| | |
|:---|:---|
| **1280 Rancho Conejo Blvd** |  |
| **Thousand Oaks, California** | **91320** |
| **(Address of Principal Executive Offices)** | **(Zip Code)** |

---

#### Registrant's Telephone Number, Including Area Code: (805) 623-4211

#### (Former Name or Former Address, if Changed Since Last Report)
Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

#### Securities registered pursuant to Section 12(b) of the Act:

---

| | | |
|:---|:---|:---|
| **Title of each class** | **Trading**<br> **Symbol(s)** | **Name of each exchange**<br> **on which registered** |
| Common Stock, par value $0.0001 per share | ATRA | The Nasdaq Stock Market LLC |

---

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

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 13(a) of the Exchange Act. ☐

------

#### Item 1.01 Entry into a Material Definitive Agreement.
On February 20, 2026, Atara Biotherapeutics, Inc., (the "Company") entered into an Amendment (the "Amendment") to the Purchase and Sale Agreement dated as of December 20, 2022 (the "Agreement") with HCR Molag Fund, L.P. ("HCR"). Under the terms of the Amendment, HCR agreed to amend the due date of the one-time of $9.0 million cash payment associated with the achievement of a certain milestone within the Amended and Restated Commercialization Agreement dated October 31, 2023 with Pierre Fabre Medicament, as amended, from June 30, 2026 to January 1, 2028. In connection with the Amendment, the Company issued a warrant to purchase up to 400,000 shares of the Company's Common Stock (the "Warrant").

The exercise price of the Warrant is equal to $0.0001 per share, subject to adjustment as provided therein, and the Warrants will be exercisable immediately and has no expiration date. The holder will not have the right to exercise any portion of the Warrant if the holder (together with its affiliates) would beneficially own in excess of 4.99% of the number of shares of Common Stock outstanding immediately after giving effect to the exercise, as such percentage ownership is determined in accordance with the terms of the Warrants.

The Warrant may be exercised through a cashless exercise, in which the net number of shares of Common Stock to be issued is determined according to a formula set forth in the Warrant.

The foregoing is only a summary of the terms of the Amendment and the Warrant and does not purport to be complete and is qualified in its entirety by reference to the full text of: (i) the Amendment, a copy of which is filed herewith as Exhibit 10.1; and (ii) the Warrant, a copy of which is attached to this report as Exhibit 4.1.

#### Item 3.02 Unregistered Sales of Equity Securities.
The information contained in Item 1.01 of this Current Report is incorporated by reference into this Item 3.02. The Company issued the Warrant pursuant to the exemption from the registration requirements of the Securities Act of 1933, as amended (the "Securities Act") available under Section 4(a)(2) of the Securities Act. Pursuant to the terms of the Warrant, the Company intends to file a registration statement relating to the resale of the Company's Common Stock underlying the Warrant, subject to the registration rights provisions of the Warrant.

#### Item 8.01 Other Events.
On February 23, 2026, the Company issued a press release titled "Atara Biotherapeutics Provides a Business Update". A copy of the press release is filed as Exhibit 99.1 and incorporated by reference into this Item 8.01.

#### Item 9.01 Financial Statements and Exhibits
(d) Exhibits.

---

| | |
|:---|:---|
| **Exhibit**<br> **No.** | **Description** |
| 4.1 | [Form of Warrant](d105335dex41.htm) |
| 10.1 | [Amendment No. 1 to the Purchase and Sale Agreement, by and between Atara Biotherapeutics, Inc. and HCR Molag Fund L.P., dated as of February 20, 2026](d105335dex101.htm) |
| 99.1 | [Press Release dated February 23, 2026](d105335dex991.htm) |
| 104 | Cover Page Interactive Data File (embedded within the Inline XBRL document). |

---

------

#### 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 hereunto duly authorized.

---

| | | |
|:---|:---|:---|
|  |  | ATARA BIOTHERAPEUTICS, INC. |
| Date: February 23, 2026 | By: | /s/ AnhCo Thieu Nguyen |
|  |  | AnhCo Thieu Nguyen<br> President and Chief Executive Officer<br> (Duly Authorized Officer and Principal Executive Officer) |

---

## Exhibit 4.1

**Exhibit 4.1** 

**THIS WARRANT AND THE SHARES OF COMMON STOCK ISSUABLE UPON THE EXERCISE OF THIS WARRANT (THE "SECURITIES") HAVE NOT BEEN REGISTERED UNDER SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), OR THE SECURITIES LAWS OF ANY STATE OF THE UNITED STATES. THE SECURITIES HAVE BEEN ACQUIRED FOR INVESTMENT AND MAY NOT BE SOLD, TRANSFERRED OR ASSIGNED UNLESS (I) SUCH SECURITIES HAVE BEEN REGISTERED FOR SALE PURSUANT TO THE SECURITIES ACT, (II) SUCH SECURITIES MAY BE SOLD PURSUANT TO RULE 144, (III) THE COMPANY HAS RECEIVED AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO IT THAT SUCH TRANSFER MAY LAWFULLY BE MADE WITHOUT REGISTRATION UNDER THE SECURITIES ACT, OR (IV) THE SECURITIES ARE TRANSFERRED WITHOUT CONSIDERATION TO AN AFFILIATE OF SUCH HOLDER OR A CUSTODIAL NOMINEE (WHICH FOR THE AVOIDANCE OF DOUBT SHALL REQUIRE NEITHER CONSENT NOR THE DELIVERY OF AN OPINION).** 

**ATARA BIOTHERAPEUTICS, INC.** 

**WARRANT TO PURCHASE COMMON STOCK** 

---

| | |
|:---|:---|
|  | Number of Shares: [ ] |
|  | (subject to adjustment) |
| Warrant No. [ ] | Original Issue Date: [ ], 2026 |

---

Atara Biotherapeutics, Inc., a Delaware corporation (the "**Company**"), hereby certifies that, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, [ ] or its registered assigns (the "**Holder**"), is entitled, subject to the terms set forth below, to purchase from the Company up to a total of [ ] shares of common stock, $0.0001 par value per share (the "**Common Stock**"), of the Company (each such share, a "**Warrant Share**" and all such shares, the "**Warrant Shares**") at an exercise price per share equal to $0.0001 per share (as adjusted from time to time as provided in Section 9 herein, the "**Exercise Price**") upon surrender of this Warrant to Purchase Common Stock (including any Warrants to Purchase Common Stock issued in exchange, transfer or replacement hereof, the "**Warrant**") at any time and from time to time on or after the date hereof (the "**Original Issue Date**"), subject to the following terms and conditions:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1. *Definitions*. For purposes of this Warrant, the following terms shall have the following meanings:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) "**Affiliate**" means any Person directly or indirectly controlled by, controlling or under common control with, a Holder, as such terms are used in and construed under Rule 405 under the Securities Act.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) "**Commission**" means the United States Securities and Exchange Commission.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) "**Closing Sale Price**" means, for any security as of any date, the last trade price for such security on the Principal Trading Market for such security, as reported by Bloomberg L.P., or, if such Principal Trading Market begins to operate on an extended hours basis and does not designate the last trade price, then the last trade price of such security prior to 4:00 P.M., New York City time, as reported by Bloomberg L.P., or if the security is not listed for trading on a national securities exchange or other trading market on the relevant date, the last quoted bid price for the security in the over-the-counter market on the relevant date as reported by OTC Markets Group Inc. (or a similar organization or agency succeeding to its functions of reporting prices). If the Closing Sale Price cannot be calculated for a security on a particular date on any of the foregoing bases, the Closing Sale Price of such security on such date shall be the fair market value as mutually determined by the Company and the Holder. If the Company and the Holder are unable to agree upon the fair market value of such security, then the Board of Directors of the Company shall use its good faith judgment to determine the fair market value. The Board of Directors' determination shall be binding upon all parties absent demonstrable error. All such determinations shall be appropriately adjusted for any stock dividend, stock split, stock combination or other similar transaction during the applicable calculation period.

------

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d) "**Marketable Securities**" means securities meeting all of the following requirements: (i) the issuer thereof is then subject to the reporting requirements of Section 13 or Section 15(d) of the Securities Exchange Act of 1934, as amended (the "**Exchange Act**"), and is then current in its filing of all required reports and other information under the Securities Act and the Exchange Act; (ii) the class and series of shares or other security of the issuer that would be received by Holder in connection with the Fundamental Transaction (as defined below) were Holder to exercise this Warrant on or prior to the closing thereof is then traded or quoted on a nationally recognized securities exchange, inter-dealer quotation system or over-the-counter market, and (iii) following the closing of such Fundamental Transaction, the Holder would not be restricted from publicly re-selling all of the issuer's shares and/or other securities that would be received by the Holder in such Fundamental Transaction were the Holder to exercise or convert this Warrant in full on or prior to the closing of such Fundamental Transaction, except to the extent that any such restriction (x) arises solely under federal or state securities laws, rules or regulations, and (y) does not extend beyond six (6) months from the closing of such Fundamental Transaction.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(e) "**Principal Trading Market**" means the national securities exchange or other trading market on which the Common Stock is primarily listed on and quoted for trading, which, as of the Original Issue Date, shall be the Nasdaq Global Select Market.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(f) "**Registrable Securities**" means (i) any Common Stock issuable upon exercise of the Warrant held by Holder as of the Original Issue Date (including all Warrant Shares issued or issuable upon exercise of the Warrant), and (ii) any Common Stock issued or issuable with respect to any shares described in subsection (i) above by way of a stock dividend or stock split or in connection with a combination of shares, recapitalization, merger, consolidation or other reorganization (it being understood that for purposes of the Warrant, Holder shall be deemed to be a holder of Registrable Securities whenever Holder has the right to then acquire or obtain from the Company any Registrable Securities, whether or not such acquisition has actually been effected). As to any particular Registrable Securities, such securities shall cease to be Registrable Securities when (A) a Registration Statement covering such securities has been declared effective by the Commission and such securities have been disposed of pursuant to such effective Registration Statement, (B) such securities are sold under circumstances in which all of the applicable conditions of Rule 144 (or any similar provisions then in force) under the Securities Act (as defined below) ("**Rule 144**") are met, (C) such securities are otherwise transferred and such transferred securities may be resold without subsequent registration under the Securities Act, or (D) such securities shall have ceased to be outstanding.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(g) "**Registration Statement**" means any registration statement of the Company which covers any of the Registrable Securities pursuant to the provisions of this Warrant, including the Prospectus, amendments and supplements to or replacements of such Registration Statement, including post-effective amendments, all exhibits and all materials incorporated by reference in such Registration Statement.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(h) "**Securities Act**" means the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(i) "**Trading Day**" means any weekday on which the Principal Trading Market is open for trading.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(j) "**Transfer Agent**" means Computershare Trust Company, Inc., the current transfer agent of the Company, located at 150 Royall Street, Canton, MA 02021, and any successor transfer agent of the Company.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2. *Issuance of Securities; Registration of Warrants*. The Company shall register ownership of this Warrant, upon records to be maintained by the Company for that purpose (the "**Warrant Register**"), in the name of the record Holder (which shall include the initial Holder or, as the case may be, any assignee to which this Warrant is permissibly assigned hereunder) from time to time. The Company may deem and treat the registered Holder of this Warrant as the absolute owner hereof for the purpose of any exercise hereof or any distribution to the Holder, and for all other purposes, absent actual notice to the contrary.

------

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3. *Registration of Transfers*. Subject to compliance with all applicable securities laws, the Company shall, or will cause its Transfer Agent to, register the transfer of all or any portion of this Warrant in the Warrant Register, upon surrender of this Warrant, and payment for all applicable transfer taxes (if any). Upon any such registration or transfer, a new warrant to purchase Common Stock in substantially the form of this Warrant (any such new warrant, a "**New Warrant**") evidencing the portion of this Warrant so transferred shall be issued to the transferee, and a New Warrant evidencing the remaining portion of this Warrant not so transferred, if any, shall be issued to the transferring Holder. The acceptance of the New Warrant by the transferee thereof shall be deemed the acceptance by such transferee of all of the rights and obligations in respect of the New Warrant that the Holder has in respect of this Warrant. The Company shall, or will cause its Transfer Agent to, prepare, issue and deliver at the Company's own expense any New Warrant under this Section 3. Until due presentment for registration of transfer, the Company may treat the registered Holder hereof as the owner and holder for all purposes, and the Company shall not be affected by any notice to the contrary.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;4. *Exercise of Warrants*.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) All or any part of this Warrant shall be exercisable by the registered Holder in any manner permitted by this Warrant at any time and from time to time on or after the Original Issue Date, and such rights shall not expire until exercised in full.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) The Holder may exercise this Warrant by delivering to the Company (i) a notice of exercise, in the form attached as Schedule 1 hereto (the "**Notice of Exercise**"), completed and duly signed, and (ii) payment of the Exercise Price for the number of Warrant Shares as to which this Warrant is being exercised in the form of a "cashless exercise" pursuant to Section 10 below. The date on which such Notice of Exercise is delivered to the Company (as determined in accordance with the notice provisions hereof) is an **"Exercise Date**." The Holder shall not be required to deliver the original Warrant in order to effect an exercise hereunder. Execution and delivery of the Notice of Exercise shall have the same effect as cancellation of the original Warrant and issuance of a New Warrant evidencing the right to purchase the remaining number of Warrant Shares, if any. **The Holder and any assignee, by acceptance of this Warrant, acknowledge and agree that, by reason of the provisions of this paragraph, following the purchase of a portion of the Warrant Shares hereunder, the number of Warrant Shares available for purchase hereunder at any given time may be less than the amount stated on the face hereof.**

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5. *Delivery of Warrant Shares*.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) Upon exercise of this Warrant, the Company shall promptly (but in no event later than three (3) Trading Days after the Exercise Date), upon the request of the Holder, cause the Transfer Agent to credit such aggregate number of shares of Common Stock to which the Holder is entitled pursuant to such exercise (the "**Exercise Shares**") to (i) the Holder's or its designee's balance account with The Depository Trust Company ("**DTC**") through its Deposit Withdrawal At Custodian system, assuming the Transfer Agent is participating in the DTC Fast Automated Securities Transfer Program (the "**FAST Program**") or (ii) in book-entry form via a direct registration system ("**DRS**") maintained by or on behalf of the Transfer Agent, in each case, so long as the Exercise Shares are eligible for resale by the Holder without volume or manner-of-sale restrictions pursuant to Rule 144 promulgated under the Securities Act (assuming cashless exercise of this Warrant) or there is an effective registration statement registering the resale of the Exercise Shares by the Holder. If the Transfer Agent is not a participant in the FAST Program or if the Exercise Shares are not (A) eligible for resale by the Holder without volume or manner-of-sale restrictions pursuant to Rule 144 promulgated under the Securities Act or (B) covered by an effective registration statement registering the resale of the Exercise Shares by the Holder, the Company shall cause the Transfer Agent to either (i) record the Exercise Shares in the name of the Holder or its designee on the certificates reflecting the Exercise Shares with an appropriate legend regarding restriction on transferability, which shall be issued and dispatched by overnight courier to the address as specified in the Exercise Notice, and on the Company's share register or (ii) issue such Exercise Shares in the name of the Holder or its designee in restricted book-entry form in the Company's share register. The Holder, or any natural person or legal entity (each, a "**Person**") so designated by the Holder to receive Warrant Shares, shall be deemed to have become the holder of record of such Warrant Shares as of the Exercise Date, irrespective of the date such Warrant Shares are credited to the Holder's DTC account, the date of the book entry positions or the date of delivery of the certificates evidencing such Warrant Shares, as the case may be.

------

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) If by the close of the third (3rd) Trading Day after the Exercise Date, the Company fails to cause the Transfer Agent to deliver to the Holder or its designee Exercise Shares in the manner required pursuant to Section 5(a), and if after such third (3rd) Trading Day and prior to the receipt of such Warrant Shares, the Holder purchases (in an open market transaction or otherwise) shares of Common Stock to deliver in satisfaction of a sale by the Holder of the Warrant Shares which the Holder anticipated receiving upon such exercise (a "**Buy-In**"), then the Company shall, within three (3) Trading Days after the Holder's request promptly honor its obligation to deliver to the Holder or its designee such Warrant Shares and pay cash to the Holder in an amount equal to the excess (if any) of Holder's total purchase price (including commercially reasonable brokerage commissions, if any) for the shares of Common Stock so purchased in the Buy-In less the product of (A) the number of shares of Common Stock purchased in the Buy-In, times (B) the Closing Sale Price of a share of Common Stock on the Exercise Date).

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) To the extent permitted by law and subject to Section 5(b), the Company's obligations to issue and deliver Warrant Shares in accordance with and subject to the terms hereof (including the limitations set forth in Section 11 below) are absolute and unconditional, irrespective of any action or inaction by the Holder to enforce the same, any waiver or consent with respect to any provision hereof, the recovery of any judgment against any Person or any action to enforce the same, or any setoff, counterclaim, recoupment, limitation or termination, or any breach or alleged breach by the Holder or any other Person of any obligation to the Company or any violation or alleged violation of law by the Holder or any other Person, and irrespective of any other circumstance that might otherwise limit such obligation of the Company to the Holder in connection with the issuance of Warrant Shares. Subject to Section 5(b), nothing herein shall limit the Holder's right to pursue any other remedies available to it hereunder, at law or in equity including, without limitation, a decree of specific performance and/or injunctive relief with respect to the Company's failure to timely deliver Exercise Shares.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6. *Charges, Taxes and Expenses*. Issuance and delivery of Exercise Shares shall be made without charge to the Holder for any issue or transfer tax, transfer agent fee or other incidental tax or expense (excluding any applicable stamp duties) in respect of the issuance of such shares, all of which taxes and expenses shall be paid by the Company; *provided*, *however*, that the Company shall not be required to pay any tax that may be payable in respect of any transfer involved in the registration of any Exercise Shares or the Warrants in a name other than that of the Holder or an Affiliate thereof. The Holder shall be responsible for all other tax liability that may arise as a result of holding or transferring this Warrant or receiving Warrant Shares upon exercise hereof.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;7. *Replacement of Warrant*. If this Warrant is mutilated, lost, stolen or destroyed, the Company shall issue or cause to be issued in exchange and substitution for and upon cancellation hereof, or in lieu of and substitution for this Warrant, a New Warrant, but only upon receipt of evidence reasonably satisfactory to the Company of such loss, theft or destruction (in such case) and, in each case, a customary and reasonable contractual indemnity, if requested by the Company. Applicants for a New Warrant under such circumstances shall also comply with such other reasonable regulations and procedures and pay such other reasonable third-party costs as the Company may prescribe. If a New Warrant is requested as a result of a mutilation of this Warrant, then the Holder shall deliver such mutilated Warrant to the Company as a condition precedent to the Company's obligation to issue the New Warrant.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;8. *Reservation of Warrant Shares*. The Company covenants that it will, at all times while this Warrant is outstanding, reserve and keep available out of the aggregate of its authorized but unissued and otherwise unreserved Common Stock, solely for the purpose of enabling it to issue Warrant Shares upon exercise of this Warrant as herein provided, the number of Warrant Shares that are initially issuable and deliverable upon the exercise of this entire Warrant, free from preemptive rights or any other contingent purchase rights of persons other than the Holder (taking into account the adjustments and restrictions of Section 9). The Company covenants that all Warrant Shares so issuable and deliverable shall, upon issuance and the payment of the applicable Exercise Price in accordance with the terms hereof, be duly and validly authorized, issued and fully paid and non-assessable. The Company will take all such actions as may be reasonably necessary to assure that such shares of Common Stock may be issued as provided herein without violation of any applicable law or regulation, or of any requirements of any securities exchange or automated quotation system upon which the Common Stock may be listed. The Company further covenants that it will not, without the prior written consent of the Holder, take any actions to increase the par value of the Common Stock at any time while this Warrant is outstanding.

------

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;9. *Certain Adjustments*. The Exercise Price and number of Warrant Shares issuable upon exercise of this Warrant are subject to adjustment from time to time as set forth in this Section 9.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) <u>Stock Dividends and Splits</u>. If the Company, at any time while this Warrant is outstanding, (i) pays a stock dividend on its Common Stock or otherwise makes a distribution on any class of capital stock issued and outstanding on the Original Issue Date and in accordance with the terms of such stock on the Original Issue Date or as amended, that is payable in shares of Common Stock, (ii) subdivides its outstanding shares of Common Stock into a larger number of shares of Common Stock, (iii) combines its outstanding shares of Common Stock into a smaller number of shares of Common Stock or (iv) issues by reclassification of shares of capital stock any additional shares of Common Stock of the Company, then in each such case the Exercise Price shall be multiplied by a fraction, the numerator of which shall be the number of shares of Common Stock outstanding immediately before such event and the denominator of which shall be the number of shares of Common Stock outstanding immediately after such event. Any adjustment made pursuant to clause (i) of this paragraph shall become effective immediately after the record date for the determination of stockholders entitled to receive such dividend or distribution, provided, however, that if such record date shall have been fixed and such dividend is not fully paid on the date fixed therefor, the Exercise Price shall be recomputed accordingly as of the close of business on such record date and thereafter the Exercise Price shall be adjusted pursuant to this paragraph as of the time of actual payment of such dividends. Any adjustment pursuant to clause (ii), (iii) or (iv) of this paragraph shall become effective immediately after the effective date of such subdivision or combination or issuance.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) <u>Pro Rata Distributions</u>. If the Company, at any time while this Warrant is outstanding, distributes to all holders of Common Stock for no consideration (i) evidences of its indebtedness, (ii) any cash or security (other than a distribution of Common Stock covered by the preceding paragraph), (iii) rights or warrants to subscribe for or purchase any security or (iv) cash or any other asset (in each case, a "**Distribution**"), other than a reclassification as to which Section 9(c) applies, then in each such case, the Holder shall be entitled to participate in such Distribution to the same extent that the Holder would have participated therein if the Holder had held the number of shares of Common Stock acquirable upon complete exercise of this Warrant (without regard to any limitations on exercise hereof, including without limitation, the ownership limitation set forth in Section 11(a) hereof) immediately before the date on which a record is taken for such Distribution, or, if no such record is taken, the date as of which the record holders of Common Stock are to be determined for the participation in such Distribution (provided, however, to the extent that the Holder's right to participate in any such Distribution would result in the Holder exceeding the ownership limitation set forth in Section 11(a) hereof, then the Holder shall not be entitled to participate in such Distribution to such extent (or in the beneficial ownership of any Common Stock as a result of such Distribution to such extent) and the portion of such Distribution shall be held in abeyance for the benefit of the Holder until such time, if ever, as the delivery to such Holder of such portion would not result in the Holder exceeding the ownership limitation set forth in Section 11(a) hereof.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) <u>Fundamental Transactions</u>. If, at any time while this Warrant is outstanding (i) the Company effects any merger or consolidation of the Company with or into another Person, in which the Company is not the surviving entity, (ii) the Company effects any sale, transfer or disposition to another Person of all or substantially all of its assets in one transaction or a series of related transactions (which, for the avoidance of doubt, shall exclude any such transactions undertaken by and amongst the Company and its subsidiaries for the purposes of a reorganization, recapitalization or similar scheme of arrangement), (iii) pursuant to any tender offer or exchange offer (whether by the Company or another Person), holders of capital stock tender shares representing more than 50% of the voting power of the capital stock of the Company and the Company or such other Person, as applicable, accepts such tender for payment, (iv) the Company consummates a stock purchase agreement or other business combination (including, without limitation, a reorganization, recapitalization, spin-off or scheme of arrangement) with another Person whereby such other Person acquires more than 50% of the voting power of the capital stock of the Company (except for any such transaction in which the stockholders of the Company immediately prior to such transaction maintain, in substantially the same proportions, the voting power of such Person immediately after the transaction) or (v) the Company effects any reclassification of the Common Stock or any compulsory share exchange pursuant to which the Common Stock is effectively converted into or exchanged for other securities, cash or property (other than as a result of a subdivision or combination of shares of Common Stock covered by Section 9(a) above) (in any such case, a "**Fundamental Transaction**"), then following such Fundamental Transaction the Holder shall have the right to receive, upon exercise of this Warrant, the same amount and kind of securities, cash or property as it would have been entitled to receive upon the occurrence of such Fundamental Transaction if it had

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been, immediately prior to such Fundamental Transaction, the holder of the number of Warrant Shares then issuable upon exercise in full of this Warrant (including and Distributions then held in abeyance pursuant to Section 9(b) above) without regard to any limitations on exercise contained herein (the "**Alternate Consideration**"). The Company shall not effect any Fundamental Transaction in which the Company is not the surviving entity or the Alternate Consideration includes securities of another Person unless (i) the Alternate Consideration is solely cash and the Company provides for the simultaneous "cashless exercise" of this Warrant pursuant to Section 10 below or (ii) prior to or simultaneously with the consummation thereof, any successor to the Company, surviving entity or other Person (including any purchaser of assets of the Company) shall assume the obligation to deliver to the Holder such Alternate Consideration as, in accordance with the foregoing provisions, the Holder may be entitled to receive, and the other obligations under this Warrant. The provisions of this paragraph (c) shall similarly apply to subsequent transactions analogous of a Fundamental Transaction type. Notwithstanding the foregoing, in the event of a Fundamental Transaction where the consideration payable to holders of Common Stock consists solely of cash, solely of Marketable Securities or a combination of cash and Marketable Securities, then this Warrant shall automatically be deemed to be exercised in full in a "cashless exercise" pursuant to Section 10 below effective immediately prior to and contingent upon the consummation of such Fundamental Transaction.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d) <u>Number of Warrant Shares</u>. Simultaneously with any adjustment to the Exercise Price pursuant to Section 9 (including any adjustment to the Exercise Price that would have been effected but for the final sentence in this paragraph (d)), the number of Warrant Shares that may be purchased upon exercise of this Warrant shall be increased or decreased proportionately, so that after such adjustment the aggregate Exercise Price payable hereunder for the increased or decreased number of Warrant Shares shall be the same as the aggregate Exercise Price in effect immediately prior to such adjustment. Notwithstanding the foregoing, in no event may the Exercise Price be adjusted below the par value of the Common Stock then in effect.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(e) <u>Calculations</u>. All calculations under this Section 9 shall be made to the nearest one-hundredth of one cent or the nearest share, as applicable.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(f) <u>Notice of Adjustments</u>. Upon the occurrence of each adjustment pursuant to this Section 9, the Company at its expense will, at the written request of the Holder, promptly compute such adjustment, in good faith, in accordance with the terms of this Warrant and prepare a certificate setting forth such adjustment, including a statement of the adjusted Exercise Price and adjusted number or type of Warrant Shares or other securities issuable upon exercise of this Warrant (as applicable), describing the transactions giving rise to such adjustments and showing in detail the facts upon which such adjustment is based. Upon written request, the Company will promptly deliver a copy of each such certificate to the Holder and to the Transfer Agent.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(g) <u>Notice of Corporate Events</u>. If, while this Warrant is outstanding, the Company (i) declares a dividend or any other distribution of cash, securities or other property in respect of its Common Stock, including, without limitation, any granting of rights or warrants to subscribe for or purchase any capital stock of the Company or any subsidiary, (ii) authorizes or approves, enters into any agreement contemplating or solicits stockholder approval for any Fundamental Transaction or (iii) authorizes the voluntary dissolution, liquidation or winding up of the affairs of the Company, then, except if such notice and the contents thereof shall be deemed to constitute material non-public information, the Company shall deliver to the Holder a notice of such transaction at least ten (10) days prior to the applicable record or effective date on which a Person would need to hold Common Stock in order to participate in or vote with respect to such transaction; provided, however, that the failure to deliver such notice or any defect therein shall not affect the validity of the corporate action required to be described in such notice. In addition, if while this Warrant is outstanding, the Company authorizes or approves, enters into any agreement contemplating or solicits stockholder approval for any Fundamental Transaction contemplated by Section 9(c), other than a Fundamental Transaction under clause (iii) of Section 9(c), then, the Company shall deliver to the Holder a notice of such Fundamental Transaction at least ten (10) days prior to the date such Fundamental Transaction is consummated.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;10. *Payment of Cashless Exercise Price*. Notwithstanding anything contained herein to the contrary, the Holder shall satisfy its obligation to pay the Exercise Price through a "cashless exercise," in which event the Company shall issue to the Holder the number of Warrant Shares in an exchange of securities effected pursuant to Section 3(a)(9) of the Securities Act as determined as follows:

X = Y [(A-B)/A]

where:

"X" equals the number of Warrant Shares to be issued to the Holder;

"Y" equals the total number of Warrant Shares with respect to which this Warrant is then being exercised;

"A" equals the Closing Sale Price per share of Common Stock as of the Trading Day on the date immediately preceding the Exercise Date; and

"B" equals the Exercise Price per Warrant Share then in effect on the Exercise Date.

For purposes of Rule 144 promulgated under the Securities Act, it is intended, understood and acknowledged that the Warrant Shares issued in such a "cashless exercise" transaction shall be deemed to have been acquired by the Holder, and the holding period for the Warrant Shares shall be deemed to have commenced, on the Original Issue Date (provided that the Commission continues to take the position that such treatment is proper at the time of such exercise).

Except as otherwise set forth herein, in no event will the exercise of this Warrant be settled in cash.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;11. *Limitations on Exercise*.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) Notwithstanding anything to the contrary contained herein, the Company shall not effect any exercise of this Warrant, and the Holder shall not be entitled to exercise this Warrant for a number of Warrant Shares in excess of that number of Warrant Shares which, upon giving effect or immediately prior to such exercise, would cause (i) the aggregate number of shares of Common Stock beneficially owned by the Holder, its Affiliates and any other Persons whose beneficial ownership of Common Stock would be aggregated with the Holder's for purposes of Section 13(d) of the Exchange Act to exceed 4.99% (the "**Maximum Percentage**") of the total number of issued and outstanding shares of Common Stock following such exercise, or (ii) the combined voting power of the securities of the Company beneficially owned by the Holder and its Affiliates and any other Persons whose beneficial ownership of Common Stock would be aggregated with the Holder's for purposes of Section 13(d) of the Exchange Act to exceed 4.99% of the combined voting power of all of the securities of the Company then outstanding following such exercise. For purposes of this Warrant, in determining the number of outstanding shares of Common Stock, the Holder may rely on the number of outstanding shares of Common Stock as reflected in (x) the Company's most recent Form 10-Q or Form 10-K, as the case may be, filed with the Commission prior to the Exercise Date, (y) a more recent public announcement by the Company or (z) any other notice by the Company or the Transfer Agent setting forth the number of shares of Common Stock outstanding. Upon the written request of the Holder, the Company shall within three (3) Trading Days confirm in writing or by electronic mail to the Holder the number of shares of Common Stock then outstanding. In any case, the number of outstanding shares of Common Stock shall be determined after giving effect to the conversion or exercise of securities of the Company, including this Warrant, by the Holder since the date as of which such number of outstanding shares of Common Stock was reported. By written notice to the Company, the Holder may from time to time increase or decrease the Maximum Percentage to any other percentage not in excess of 19.99% specified in such notice; provided that any such increase will not be effective until the sixty-first (61st) day after such notice is delivered to the Company. For purposes of this Section 11(a), the aggregate number of shares of Common Stock or voting securities beneficially owned by the Holder and its Affiliates and any other Persons whose beneficial ownership of Common Stock would be aggregated with the Holder's for purposes of Section 13(d) of the Exchange Act shall include the shares of Common Stock issuable upon the exercise of this Warrant with respect to which such determination is being made, but shall exclude the number of shares of Common Stock which would be issuable upon (x) exercise of the remaining unexercised and non-cancelled portion of this Warrant by the Holder and (y) exercise or conversion of the unexercised, non-converted or non-cancelled portion of any other securities of the Company that do not have voting power (including without limitation any securities of the Company which would entitle the holder thereof to acquire at any time Common Stock, including without limitation any debt, preferred stock, right, option, warrant or other instrument that is at any time convertible into or exercisable or exchangeable for, or otherwise entitles the holder thereof to receive, Common Stock), is subject to a limitation on conversion or exercise analogous to the limitation contained herein and is beneficially owned by the Holder or any of its Affiliates and other Persons whose beneficial ownership of Common Stock would be aggregated with the Holder's for purposes of Section 13(d) of the Exchange Act.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) This Section 11 shall not restrict the number of shares of Common Stock which a Holder may receive or beneficially own in order to determine the amount of securities or other consideration that such Holder may receive in the event of a Fundamental Transaction as contemplated in Section 9(c) of this Warrant. For purposes of clarity, the shares of Common Stock issuable pursuant to the terms of this Warrant in excess of the Maximum Percentage shall not be deemed to be beneficially owned by the Holder or its Affiliates for any purpose including for purposes of Section 13(d) of the Exchange Act and the rules promulgated thereunder or Section 16 of the Exchange Act and the rules promulgated thereunder, including Rule 16a-1(a)(1).

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;12. *No Fractional Shares*. No fractional Warrant Shares will be issued in connection with any exercise of this Warrant. In lieu of any fractional shares that would otherwise be issuable, the number of Warrant Shares to be issued shall be rounded down to the next whole number and the Company shall pay the Holder in cash the fair market value (based on the Closing Sale Price) for any such fractional shares.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;13. *Notices*. Any and all notices or other communications or deliveries hereunder (including, without limitation, any Notice of Exercise) shall be in writing and shall be deemed given and effective on the earliest of (i) the date of transmission, if such notice or communication is delivered via confirmed e-mail prior to 5:30 P.M., New York City time, on a Trading Day, (ii) the next Trading Day after the date of transmission, if such notice or communication is delivered via confirmed e-mail on a day that is not a Trading Day or later than 5:30 P.M., New York City time, on any Trading Day, (iii) the Trading Day following the date of mailing, if sent by nationally recognized overnight courier service specifying next business day delivery, or (iv) upon actual receipt by the Person to whom such notice is required to be given, if by hand delivery. The addresses and e-mail addresses for such communications shall be:

If to the Company:

Atara Biotherapeutics, Inc.

Attention: Head of Legal

1280 Rancho Conejo Blvd

Thousand Oaks, California 91320

Telephone: (805) 623-4211

Email: [ ]

If to the Holder:

[ ]

Or, in each of the above instances, to such other address or e-mail address as the recipient party has specified by written notice given to each other party at least five (5) days prior to the effectiveness of such change.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;14. *Warrant Agent*. The Company shall initially serve as warrant agent under this Warrant. Upon ten (10) days' notice to the Holder, the Company may appoint a new warrant agent. Any corporation into which the Company or any new warrant agent may be merged or any corporation resulting from any consolidation to which the Company or any new warrant agent shall be a party or any corporation to which the Company or any new warrant agent transfers substantially all of its corporate trust or shareholders services business shall be a successor warrant agent under this Warrant without any further act. Any such successor warrant agent shall promptly cause notice of its succession as warrant agent to be mailed (by first class mail, postage prepaid) to the Holder at the Holder's last address as shown on the Warrant Register.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;15. *Registration Rights.*

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) The Company shall prepare and file or cause to be prepared and filed with the Commission, no later than thirty (30) days from the Original Issue Date (the "**Filing Deadline**"), a registration statement for an offering to be made on a continuous basis pursuant to Rule 415 of the Securities Act registering the resale from time to time by the Holder of all Registrable Securities held by the Holder (the "**Resale Registration Statement**"). The Resale Registration Statement shall be on Form S-3 or, if the use of Form S-3 is not then available to the Company, on Form S-1 or such other appropriate form permitting registration of such Registrable Securities for resale by the Holder. The Company shall use reasonable best efforts to cause the Resale Registration Statement to be declared effective at the earliest possible date after filing, but in no event shall the Resale Registration Statement be declared effective later than the earlier of (i) forty-five (45) days following the Filing Deadline or (ii) five (5) business days after the Commission notifies the Company that it will not review the Resale Registration Statement, if applicable (the "**Effectiveness Deadline**"); provided, that the Effectiveness Deadline shall be extended to no more than forty-five (45) days after the Filing Deadline if the Registration Statement is reviewed by, and receives comments from, the Commission. Once effective, the Company shall use reasonable best efforts to keep the Resale Registration Statement continuously effective and supplemented and amended to the extent necessary to ensure that such Registration Statement is available or, if not available, to ensure that another registration statement is available, under the Securities Act at all times until such date as all Registrable Securities covered by the Resale Registration Statement have been disposed of in accordance with the intended method(s) of distribution set forth in such Registration Statement or such securities have been requested to be withdrawn from registration by the Holder (the "**Effectiveness Period**"). The Resale Registration Statement shall contain a prospectus in such form as to permit the Holder to sell such Registrable Securities pursuant to Rule 415 under the Securities Act (or any successor or similar provision adopted by the Commission then in effect) at any time beginning on the effective date for such Registration Statement, and shall provide that such Registrable Securities may be sold pursuant to any method or combination of methods legally available to, and requested by, the Holder.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) The Company shall notify the Holder in writing of the effectiveness of the Resale Registration Statement as soon as practicable, and in any event within one (1) business day after the Resale Registration Statement becomes effective, and shall furnish to Holder, without charge, such number of copies of the Resale Registration Statement (including any amendments, supplements and exhibits), the prospectus contained therein (including each preliminary prospectus and all related amendments and supplements) and any documents incorporated by reference in the Resale Registration Statement or such other documents as the Holder may reasonably request in order to facilitate the sale of the Registrable Securities in the manner described in the Resale Registration Statement.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) Subject to the provisions of Section 15(a) above, the Company shall promptly prepare and file with the Commission from time to time such amendments and supplements to (or replacements of) the Resale Registration Statement and prospectus used in connection therewith as may be necessary to keep the Resale Registration Statement (or replacements thereof) effective and to comply with the provisions of the Securities Act with respect to the disposition of all the Registrable Securities during the Effectiveness Period. If any Resale Registration Statement filed pursuant to Section 15(a) is filed on Form S-3 and thereafter the Company becomes ineligible to use such registration statement for secondary sales, the Company shall promptly notify the Holder of such ineligibility and shall file a shelf registration on Form S-1 or other appropriate form as promptly as practicable (but no later than 14 calendar days after becoming ineligible to use Form S-3) to replace the Resale Registration Statement and use its reasonable best efforts to have the such replacement Resale Registration Statement declared effective as promptly as practicable and shall cause such replacement Resale Registration Statement to remain effective, and to be supplemented and amended to the extent necessary to ensure that such Resale Registration Statement is available or, if not available, that another Resale Registration Statement is available, for the resale of all the Registrable Securities held by the Holder until all such Registrable Securities have been sold; provided, however, that at any time the Company once again becomes eligible to use Form S-3, the Company shall cause such replacement Resale Registration Statement to be amended, or shall file a new replacement Resale Registration Statement, such that the Resale Registration Statement is once again on Form S-3.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;16. *Miscellaneous*.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a) <u>No Rights as a Stockholder</u>. Except as otherwise set forth in this Warrant, (i) the Holder, solely in such Person's capacity as a holder of this Warrant, shall not be entitled to vote or be deemed the holder of share capital of the Company for any purpose, nor (ii) shall anything contained in this Warrant be construed to confer upon the Holder, solely in such Person's capacity as the Holder of this Warrant, any of the rights of a stockholder of the Company or any right to vote, give or withhold consent to any corporate action (whether any reorganization, issue of stock, reclassification of stock, consolidation, merger, amalgamation, conveyance or otherwise), receive notice of meetings, receive dividends or subscription rights, or otherwise, prior to the issuance to the Holder of the Warrant Shares which such Person is then entitled to receive upon the due exercise of this Warrant. In addition, nothing contained in this Warrant shall be construed as imposing any liabilities on the Holder to purchase any securities (upon exercise of this Warrant or otherwise) or as a stockholder of the Company, whether such liabilities are asserted by the Company or by creditors of the Company.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b) <u>Authorized Shares</u>. Except and to the extent as waived or consented to by the Holder, the Company shall not by any action, including, without limitation, amending its certificate or articles of incorporation or through any reorganization, transfer of assets, consolidation, merger, dissolution, issue or sale of securities or any other voluntary action, avoid or seek to avoid the observance or performance of any of the terms of this Warrant, but will at all times in good faith assist in the carrying out of all such terms and in the taking of all such actions as may be necessary or appropriate to protect the rights of Holder as set forth in this Warrant against impairment. Without limiting the generality of the foregoing, the Company will (i) not increase the par value of any Warrant Shares above the amount payable therefor upon such exercise immediately prior to such increase in par value, (ii) take all such action as may be necessary or appropriate in order that the Company may validly and legally issue fully paid and non-assessable Warrant Shares upon the exercise of this Warrant, and (iii) use commercially reasonable efforts to obtain all such authorizations, exemptions or consents from any public regulatory body having jurisdiction thereof as may be necessary to enable the Company to perform its obligations under this Warrant.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c) <u>Successors and Assigns</u>. Subject to compliance with applicable securities laws, this Warrant may be assigned by the Holder. This Warrant may not be assigned by the Company without the written consent of the Holder, except to a successor in the event of a Fundamental Transaction. This Warrant shall be binding on and inure to the benefit of the Company and the Holder and their respective successors and assigns. Subject to the preceding sentence, nothing in this Warrant shall be construed to give to any Person other than the Company and the Holder any legal or equitable right, remedy or cause of action under this Warrant. This Warrant may be amended only in writing signed by the Company and the Holder, or their successors and assigns.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d) <u>Amendment and Waiver</u>. Except as otherwise provided herein, this Warrant may only be modified or amended or the provisions hereof waived with the written consent of the Company and the Holder.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(e) <u>Acceptance</u>. Receipt of this Warrant by the Holder shall constitute acceptance of and agreement to all of the terms and conditions contained herein.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(f) <u>Governing Law; Jurisdiction</u>. ALL QUESTIONS CONCERNING THE CONSTRUCTION, VALIDITY, ENFORCEMENT AND INTERPRETATION OF THIS WARRANT SHALL BE GOVERNED BY AND CONSTRUED AND ENFORCED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK WITHOUT REGARD TO THE PRINCIPLES OF CONFLICTS OF LAW THEREOF. EACH OF THE COMPANY AND THE HOLDER AGREES THAT ALL LEGAL PROCEEDINGS CONCERNING THE INTERPRETATIONS, ENFORCEMENT AND DEFENSE OF THE TRANSACTIONS CONTEMPLATED BY THIS AGREEMENT AND ANY OTHER TRANSACTION DOCUMENTS (WHETHER BROUGHT AGAINST A PARTY HERETO OR ITS RESPECTIVE AFFILIATES, DIRECTORS, OFFICERS, SHAREHOLDERS, PARTNERS, MEMBERS, EMPLOYEES OR AGENTS) SHALL BE COMMENCED EXCLUSIVELY IN THE STATE AND FEDERAL COURTS SITTING IN THE CITY OF NEW YORK. EACH PARTY HEREBY IRREVOCABLY SUBMITS TO THE EXCLUSIVE JURISDICTION OF THE STATE AND FEDERAL COURTS SITTING IN THE CITY OF NEW YORK, BOROUGH OF MANHATTAN, FOR THE ADJUDICATION OF ANY DISPUTE HEREUNDER OR IN CONNECTION HEREWITH OR WITH ANY TRANSACTION CONTEMPLATED HEREBY OR DISCUSSED HEREIN (INCLUDING WITH RESPECT TO THE ENFORCEMENT OF ANY OF THE TRANSACTION DOCUMENTS), AND HEREBY IRREVOCABLY WAIVES, AND AGREES NOT TO ASSERT IN ANY SUIT, ACTION OR PROCEEDING, ANY CLAIM THAT IT IS NOT PERSONALLY SUBJECT TO THE JURISDICTION OF ANY SUCH COURT, THAT SUCH

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ACTION OR PROCEEDING IS IMPROPER OR IS AN INCONVENIENT VENUE FOR SUCH PROCEEDING. EACH OF THE COMPANY AND THE HOLDER HEREBY IRREVOCABLY WAIVES PERSONAL SERVICE OF PROCESS AND CONSENTS TO PROCESS BEING SERVED IN ANY SUCH SUIT, ACTION OR PROCEEDING BY MAILING A COPY THEREOF VIA REGISTERED OR CERTIFIED MAIL OR OVERNIGHT DELIVERY (WITH EVIDENCE OF DELIVERY) TO SUCH PERSON AT THE ADDRESS IN EFFECT FOR NOTICES TO IT AND AGREES THAT SUCH SERVICE SHALL CONSTITUTE GOOD AND SUFFICIENT SERVICE OF PROCESS AND NOTICE THEREOF. NOTHING CONTAINED HEREIN SHALL BE DEEMED TO LIMIT IN ANY WAY ANY RIGHT TO SERVE PROCESS IN ANY MANNER PERMITTED BY LAW. EACH OF THE COMPANY AND THE HOLDER HEREBY WAIVES ALL RIGHTS TO A TRIAL BY JURY.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(g) <u>Headings</u>. The headings herein are for convenience only, do not constitute a part of this Warrant and shall not be deemed to limit or affect any of the provisions hereof.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(h) <u>Severability</u>. In case any one or more of the provisions of this Warrant shall be invalid or unenforceable in any respect, the validity and enforceability of the remaining terms and provisions of this Warrant shall not in any way be affected or impaired thereby, and the Company and the Holder will attempt in good faith to agree upon a valid and enforceable provision which shall be a commercially reasonable substitute therefor, and upon so agreeing, shall incorporate such substitute provision in this Warrant.

[REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

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IN WITNESS WHEREOF, the Company has caused this Warrant to be duly executed by its authorized officer as of the date first indicated above.

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| | |
|:---|:---|
| **ATARA BIOTHERAPEUTICS, INC.** | **ATARA BIOTHERAPEUTICS, INC.** |
| By: |  |
|  | Name: |
|  | Title: |

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Signature Page to Atara Biotherapeutics, Inc. Warrant to Purchase Common Stock

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**SCHEDULE 1** 

**FORM OF NOTICE OF EXERCISE** 

To be executed by the Holder to purchase shares of Common Stock under the Warrant

Ladies and Gentlemen:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(1) The undersigned is the Holder of Warrant No. ___ (the "Warrant") issued by Atara Biotherapeutics, Inc., a Delaware corporation (the "Company"). Capitalized terms used herein and not otherwise defined herein have the respective meanings set forth in the Warrant.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(2) The undersigned hereby exercises its right to purchase ___________ Warrant Shares pursuant to the Warrant.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(3) The Holder intends that payment of the Exercise Price shall be made as a "cashless exercise" under Section 10 of the Warrant.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(4) Pursuant to this Notice of Exercise, the Company shall deliver to the Holder Warrant Shares determined in accordance with the terms of the Warrant. The Warrant Shares shall be delivered (check one):

☐ to the following DWAC Account Number:<u> </u>

☐ in book-entry form via a direct registration system

☐ in restricted book entry form in the Company's share register

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(5) By its delivery of this Notice of Exercise, the undersigned represents and warrants to the Company that in giving effect to the exercise evidenced hereby (i) the Holder is an "accredited investor" as defined in Regulation D promulgated under the Securities Act of 1933, as amended, and (b) the Holder will not beneficially own in excess of the number of shares of Common Stock (as determined in accordance with Section 13(d) of the Securities Exchange Act of 1934, as amended) permitted to be owned under Section 11(a) of the Warrant to which this notice relates.

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| |
|:---|
| Dated: |
| Name of Holder: |
| By: |
| Name: |
| Title: |

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(Signature must conform in all respects to name of Holder as specified on the face of the Warrant)

Schedule 1 to Atara Biotherapeutics, Inc. Form of Warrant to Purchase Common Stock

## Exhibit 10.1

**Exhibit 10.1** 

**[\*\*\*] = CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED BY [\*\*\*], HAS BEEN OMITTED BECAUSE IT IS NOT MATERIAL, AND IS THE TYPE THAT THE REGISTRANT TREATS AS PRIVATE OR CONFIDENTIAL** 

**AMENDMENT TO** 

**PURCHASE AND SALE AGREEMENT** 

This **AMENDMENT TO THE PURCHASE AND SALE AGREEMENT** (this "**Amendment**"), is entered into as of February 20, 2026 (the "**Amendment Effective Date**"), by and between Atara Biotherapeutics, Inc. ("**Atara**" or "**Seller**") and HCR Molag Fund, L.P. ("**HCR**" or "**Purchaser**") and amends that certain Purchase and Sale Agreement, dated as of December 20, 2022, by and between Atara and HCR (the "**Agreement**"). Atara and HCR are referred to in this Amendment individually as a "**Party**" and collectively as the "**Parties**". Capitalized terms used and not otherwise defined herein shall have the respective meanings given to such terms in the Agreement.

**RECITALS** 

**WHEREAS**, the Parties have mutually agreed to amend the Agreement as follows, in accordance with <u>Section</u> <u>10.12</u> of the Agreement.

**NOW, THEREFORE**, in consideration of the various promises and undertakings set forth herein, and on the terms and subject to the conditions set forth herein, the Parties hereby agree as follows:

**ARTICLE I** 

**AMENDMENT** 

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1. <u>Amendment to Section</u> <u>2.6 of the Agreement</u>. Section 2.6 of the Agreement is hereby deleted in its entirety and replaced with the following:

"Section 2.6 <u>Special Payment</u>. If [\*\*\*] has not been achieved on or prior to January 1, 2028, then within [\*\*\*] after January 1, 2028, Seller shall make a one-time cash payment to Purchaser in the amount of $9,000,000 ("**Special Payment**"). If the Special Payment is made, in consideration for the Special Payment, the Purchaser shall transfer all of its right, title and interest in the [\*\*\*] to Seller, and shall take such action as Seller reasonably requests (at Purchaser's sole expense) to evidence such transfer, including entering into a bill of sale."

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2. <u>Consideration</u>. As consideration for this Amendment, Atara agrees to issue and HCR agrees to accept, a pre-funded warrant, in substantially the form attached hereto as **<u>Exhibit A</u>** (the "**Warrant")**, to purchase an aggregate of Four Hundred Thousand (400,000) shares (the "**Warrant Shares**") of common stock, $0.0001 par value of Atara (the "**Common Stock**").

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3. <u>Full Force and Effect</u>. Except as specifically modified or waived herein, all other terms and conditions of the Agreement are unchanged and shall remain in full force and effect.

**ARTICLE II** 

**OTHER PROVISIONS** 

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1. <u>Seller Representations and Warranties</u>. Seller hereby represents and warrants to Purchaser as of the date of this Amendment as follows:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a. <u>Organization</u>. The Seller is a corporation duly incorporated, validly existing and in good standing under
the laws of the State of Delaware and has all corporate power and authority, and all licenses, permits, franchises, authorizations, consents and approvals of all Governmental Authorities, required to own its property and conduct its business, as now
conducted, in all material respects.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;b. <u>Authorization</u>. The Seller has all necessary corporate power and authority to execute and deliver this
Amendment and the Warrant, to perform its obligations hereunder and thereunder and to consummate the transactions contemplated hereby and thereby, including the issuance of the Warrant Shares upon exercise of the Warrant. The execution and delivery
of each of the Amendment and the Warrant and the performance by the Seller of its obligations hereunder and thereunder have been duly authorized by all necessary corporate action on the part of the Seller. Each of the Amendment and the Warrant has
been duly executed and delivered by an authorized officer of the Seller. Each of the Amendment and the Warrant constitutes the legal, valid and binding obligation of the Seller, enforceable against the Seller in accordance with its terms, subject to
applicable bankruptcy, insolvency, reorganization, moratorium or similar laws affecting creditors' rights generally and general equitable principles. <u> </u> 

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;c. <u>Valid Issuance</u>. The Warrant Shares have been duly and validly authorized and reserved for issuance and,
upon issuance pursuant to the terms of the Warrant against full payment therefor in accordance with the terms of the Warrant, will be duly and validly issued, fully paid and non-assessable and will be issued
free and clear of any liens or other restrictions (other than restrictions on transfer under applicable state and federal securities laws), and the Purchaser shall be entitled to all rights accorded to a holder of Common Stock. The issuance and
delivery of the Warrant does not, and the exercise in full of the Warrant and the issuance and delivery of the Warrant Shares thereupon will not, (i) obligate the Seller to offer to issue, or issue, shares of Common Stock or other securities to
any Person pursuant to any preemptive rights, rights of first refusal, rights of participation or similar rights, or (ii) result in any adjustment (automatic, at the election of any Person or otherwise) of the exercise, conversion, exchange or
reset price under, or any other anti-dilution adjustment pursuant to, any outstanding securities of the Seller. The offer and sale of the Warrant and the Warrant Shares to the Purchaser is, and will be, (A) exempt from the registration and
prospectus delivery requirements of the Securities Act of 1933, as amended (the "**Securities Act**") and (B) exempt from (or otherwise not subject to) the registration and qualification requirements of applicable securities laws
of the states of the United States.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;d. <u>No Conflicts</u>. The execution and delivery by the Seller of the Amendment and the Warrant, the performance
by the Seller of its obligations hereunder or thereunder, and the consummation by the Seller of the transactions contemplated hereby or thereby (including the issuance of the Warrant Shares), will not (i) contravene, conflict with or violate
any term or provision of any of the organizational documents of the Seller or any of its Subsidiaries, (ii) except as would not reasonably be expected to have a Material Adverse Effect, contravene, conflict with or violate, or give any
Governmental Authority or other Person the right to exercise any remedy or obtain any relief under, any Applicable Law or any judgment, order, writ, decree, permit or license of any Governmental Authority to which the Seller or any of its
Subsidiaries or any of their respective assets or properties may be subject or bound, or (iii) except as would not reasonably be expected to have a Material Adverse Effect, result in a breach or violation of, constitute a default (with or
without notice or lapse of time, or both) under,

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or give any Person the right to exercise any remedy or obtain any additional rights under, or accelerate the maturity or performance of, or payment under, or cancel or terminate, any contract, agreement, indenture, lease, license, deed, commitment, obligation or instrument to which the Seller or any of its Subsidiaries is a party or by which the Seller or any of its Subsidiaries or any of their respective assets or properties is bound.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;e. <u>Governmental and Third Party Authorizations</u>. The execution and delivery by the Seller of the Amendment
and the Warrant, the performance by the Seller of its obligations hereunder and thereunder, and the consummation by the Seller of the transactions contemplated hereby and thereby (including the issuance of the Warrant Shares) do not require any
consent, approval, license, order, authorization or declaration from, notice to, action or registration by, or filing with, any Governmental Authority or any other Person, except for (i) the filing of a Current Report on Form 8-K with the SEC and (ii) such consents, the failure of which to be obtained or made, would not reasonably be expected to have a Material Adverse Effect.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;f. <u>No Integration or Aggregation</u>. The Seller has not, directly or indirectly, sold, offered for sale,
solicited offers to buy or otherwise negotiated in respect of, any security (as defined in the Securities Act) which, to its knowledge, is or will be (i) integrated with the offer and issuance of the Warrant or Warrant Shares pursuant to this
Amendment for purposes of the Securities Act or (ii) aggregated with prior offerings by the Seller for the purposes of the rules and regulations of the Nasdaq Global Select Market. Neither the Seller nor any of its Affiliates, its subsidiaries
nor any Person acting on their behalf has, directly or indirectly, made any offers or sales of any Seller security or solicited any offers to buy any Seller security, under circumstances that would adversely affect reliance by the Seller on
Section 4(a)(2) of the Securities Act and/or Rule 506 of Regulation D promulgated thereunder for the exemption from registration for the transactions contemplated hereby.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;g. <u>No Disqualification Events</u>. Neither the Seller nor any of its (i) predecessors, (ii) Affiliates,
(iii) directors, (iv) executive officers, (v) non-executive officers participating in the placement contemplated by this Amendment, (vi) beneficial owners of 20% or more of its outstanding
voting equity securities (calculated on the basis of voting power), (vii) promoters or (viii) investment managers (including any of such investment managers' directors, executive officers or officers participating in the placement
contemplated by this Amendment) or general partners or managing members of such investment managers (including any of such general partners' or managing members' directors, executive officers or officers participating in the placement
contemplated by this Amendment) is subject to the disqualification provisions of Rule 506(d)(1)(i-viii) of Regulation D under the Securities Act (a "**Disqualification Event** "). The Seller has complied, to the extent applicable, with
its disclosure obligations under Rule 506(e).

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2. <u>Purchaser Representations and Warranties</u>. Purchaser hereby represents and warrants to Seller as of the date of this Amendment as follows:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a. <u>Organization</u>. The Purchaser is a limited liability partnership duly organized, validly existing and in
good standing under the laws of Delaware.

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;b. <u>Authorization</u>. The Purchaser has all necessary limited partnership power and authority to execute and
deliver the Amendment, to perform its obligations hereunder and to consummate the transactions contemplated hereby. The execution and delivery of the Amendment and the performance by the Purchaser of its obligations hereunder have been duly
authorized by the Purchaser. The Amendment has been duly executed and delivered by the Purchaser. The Amendment constitutes the legal, valid and binding obligation of the Purchaser, enforceable against the Purchaser in accordance with its respective
terms, subject to applicable bankruptcy, insolvency, reorganization, moratorium or similar laws affecting creditors' rights generally, and general equitable principles.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;c. <u>Accredited Investor</u>. The Purchaser is an "accredited investor" as that term is defined in
Regulation D promulgated pursuant to the Securities Act.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;3. <u>Entire Agreement</u>. This Amendment, together with the Agreement and all exhibits thereto and references therein, constitute the entire agreement among the parties and shall supersede any and all previous contracts, arrangements or understandings between the parties with respect to the subject matter herein. In the event of any conflict or inconsistency between the terms of in this Amendment and the Agreement, the terms of this Amendment will control.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;4. <u>Modification</u>. No waiver, alteration or modification of any of the provisions of this Amendment shall be binding unless made in writing and signed by the Parties.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;5. <u>Counterparts</u>. This Amendment may be executed in any number of counterparts and by each of the Parties in separate counterparts, each of which when so executed shall be deemed to be an original and all of which taken together shall constitute one and the same agreement. Signatures of the Parties transmitted by electronic means shall be deemed to be their original signatures for all purposes.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;6. <u>Governing Law</u>. This Amendment will be governed by and in accordance with the laws of the State of New York without giving effect to any choice of law principles that would require the application of the laws of a different jurisdiction.

*[Signature Page Follows]* 

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IN WITNESS WHEREOF, the Parties intending to be bound have caused this Amendment to be executed by their duly authorized representatives as of the Amendment Effective Date.

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| | | | |
|:---|:---|:---|:---|
| **ATARA BIOTHERAPEUTICS, INC.** | **ATARA BIOTHERAPEUTICS, INC.** | **HCR MOLAG FUND, L.P.** | **HCR MOLAG FUND, L.P.** |
|  |  | **By: HCR MOLAG FUND GP, LLC**, its | **By: HCR MOLAG FUND GP, LLC**, its |
|  |  | general partner | general partner |
| By: | /s/ Cokey Nguyen | By: | /s/ Clarke B. Futch |
| Name: | Cokey Nguyen | Name: | Clarke B. Futch |
| Title: | President & CEO | Title: | Chief Executive Officer |
| Date: | February 20, 2026 | Date: | 2/20/2026 |

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**EXHIBIT A** 

FORM OF WARRANT

## Exhibit 99.1

**Exhibit 99.1** 

**Atara Biotherapeutics Provides a Business Update** 

*Atara renegotiates one-time milestone payment with HCRx* 

THOUSAND OAKS, California —(BUSINESS WIRE)— <u>Atara Biotherapeutics, Inc</u>. (Nasdaq: ATRA), a leader in T-cell immunotherapy, leveraging its novel allogeneic Epstein-Barr virus (EBV) T-cell platform to develop transformative therapies for patients with cancer and autoimmune diseases, today announced that the Company entered into an amendment (the Amendment) to the Purchase and Sale Agreement dated as of December 20, 2022 with a fund managed by HealthCare Royalty ("HCRx"). Under the terms of the Amendment, HCRx agreed to amend the due date of the one-time of $9.0 million cash payment associated with the achievement of a certain milestone within the Amended and Restated Commercialization Agreement dated October 31, 2023, with Pierre Fabre Medicament, as amended, from June 30, 2026 to January 1, 2028.

"We are thankful for this extension to our one-time cash payment to HCRx", said Cokey Nguyen, President and Chief Executive Officer of Atara. "This flexibility allows us to focus on addressing the concerns in the latest CRL with the agency, supporting our partners, Pierre Fabre. We believe in the potential of tabelecleucel and are optimistic about the path forward."

In connection with the Amendment, the Company issued a warrant to purchase up to 400,000 shares of the Company's Common Stock. The exercise price of the Warrant is equal to $0.0001 per share, subject to adjustment as provided therein, and the Warrant will be exercisable immediately and have no expiration date. The exercise of the Warrant is subject to a beneficial ownership limit as set forth in the Warrant.

"Tabelecleucel is proving to be an important option for European patients suffering from relapsed or refractory EBV+ PTLD, an ultra-rare and aggressive lymphoma", said Clarke Futch, Chairman and Chief Executive Officer at HCRx. "This amendment to our agreement provides Atara and their partner time to work with the FDA for a path to approval in the United States, where there remain limited treatment options and significant unmet need."

**About Atara Biotherapeutics, Inc.** 

Atara is harnessing the natural power of the immune system to develop off-the-shelf cell therapies for difficult-to-treat cancers and autoimmune conditions that can be rapidly delivered to patients from inventory. With cutting-edge science and differentiated approach, Atara is the first company in the world to receive regulatory approval of an allogeneic T-cell immunotherapy. Our advanced and versatile T-cell platform does not require T-cell receptor or HLA gene editing and forms the basis of a diverse portfolio of investigational therapies that target EBV, the root cause of certain diseases. Atara is headquartered in Southern California. For more information, visit atarabio.com and follow <u>@Atarabio</u> on <u>X</u> and <u>LinkedIn</u>.

**Forward-Looking Statements** 

This press release contains or may imply "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. For example, forward-looking statements include statements regarding: (1) the development, timing and progress of tab-cel and (2) the timing of the $9.0 million cash payment to HCRx. Because such statements deal with future events and are based on Atara's current expectations, they are subject to various risks and uncertainties and actual results, performance or achievements of Atara could differ materially from

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those described in or implied by the statements in this press release. These forward-looking statements are subject to risks and uncertainties, including, without limitation, risks and uncertainties associated with our year-end the costly and time-consuming pharmaceutical product development process and the uncertainty of clinical success; risks related to FDA's review of tab-cel; our ability to access capital, and the sufficiency of Atara's cash resources and access to additional capital on favorable terms or at all; and other risks and uncertainties affecting Atara, including those discussed in Atara's filings with the Securities and Exchange Commission, including in the "Risk Factors" and "Management's Discussion and Analysis of Financial Condition and Results of Operations" sections of the Company's most recently filed periodic reports on Form 10-K and Form 10-Q and subsequent filings and in the documents incorporated by reference therein. Except as otherwise required by law, Atara disclaims any intention or obligation to update or revise any forward-looking statements, which speak only as of the date hereof, whether as a result of new information, future events or circumstances or otherwise.

**Investor and Media Relations** 

Amber Daugherty

Sr. Director, Strategy and Operations

<u>adaugherty@atarabio.com</u>