Amendment: SEC Form SCHEDULE 13D/A filed by Atara Biotherapeutics Inc.
|
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549 |
SCHEDULE 13D
Under the Securities Exchange Act of 1934
(Amendment No. 1)
|
Atara Biotherapeutics, Inc. (Name of Issuer) |
Common Stock, par value $0.0001 per share (Title of Class of Securities) |
046513206 (CUSIP Number) |
Joshua Garcia Redmile Group, LLC, One Letterman Drive Bldg D, Ste D3-300 San Francisco, CA, 94129 (415) 489-9980 (Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications) |
11/12/2025 (Date of Event Which Requires Filing of This Statement) |

SCHEDULE 13D
|
| CUSIP No. | 046513206 |
| 1 |
Name of reporting person
Redmile Group, LLC | ||||||||
| 2 | Check the appropriate box if a member of a Group (See Instructions)
(a)
(b)
| ||||||||
| 3 | SEC use only | ||||||||
| 4 |
Source of funds (See Instructions)
OO | ||||||||
| 5 |
Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)
![]() | ||||||||
| 6 | Citizenship or place of organization
DELAWARE
| ||||||||
| Number of Shares Beneficially Owned by Each Reporting Person With: |
| ||||||||
| 11 | Aggregate amount beneficially owned by each reporting person
751,223.00 | ||||||||
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)
![]() | ||||||||
| 13 | Percent of class represented by amount in Row (11)
9.9 % | ||||||||
| 14 | Type of Reporting Person (See Instructions)
IA, OO |
SCHEDULE 13D
|
| CUSIP No. | 046513206 |
| 1 |
Name of reporting person
Jeremy C. Green | ||||||||
| 2 | Check the appropriate box if a member of a Group (See Instructions)
(a)
(b)
| ||||||||
| 3 | SEC use only | ||||||||
| 4 |
Source of funds (See Instructions)
OO | ||||||||
| 5 |
Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)
![]() | ||||||||
| 6 | Citizenship or place of organization
UNITED KINGDOM
| ||||||||
| Number of Shares Beneficially Owned by Each Reporting Person With: |
| ||||||||
| 11 | Aggregate amount beneficially owned by each reporting person
751,223.00 | ||||||||
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)
![]() | ||||||||
| 13 | Percent of class represented by amount in Row (11)
9.9 % | ||||||||
| 14 | Type of Reporting Person (See Instructions)
IN, HC |
SCHEDULE 13D
|
| CUSIP No. | 046513206 |
| 1 |
Name of reporting person
RedCo I, L.P. | ||||||||
| 2 | Check the appropriate box if a member of a Group (See Instructions)
(a)
(b)
| ||||||||
| 3 | SEC use only | ||||||||
| 4 |
Source of funds (See Instructions)
WC | ||||||||
| 5 |
Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)
![]() | ||||||||
| 6 | Citizenship or place of organization
DELAWARE
| ||||||||
| Number of Shares Beneficially Owned by Each Reporting Person With: |
| ||||||||
| 11 | Aggregate amount beneficially owned by each reporting person
347,442.00 | ||||||||
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)
![]() | ||||||||
| 13 | Percent of class represented by amount in Row (11)
4.7 % | ||||||||
| 14 | Type of Reporting Person (See Instructions)
PN |
SCHEDULE 13D
|
| CUSIP No. | 046513206 |
| 1 |
Name of reporting person
Redmile Biopharma Investments II, L.P. | ||||||||
| 2 | Check the appropriate box if a member of a Group (See Instructions)
(a)
(b)
| ||||||||
| 3 | SEC use only | ||||||||
| 4 |
Source of funds (See Instructions)
WC | ||||||||
| 5 |
Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)
![]() | ||||||||
| 6 | Citizenship or place of organization
DELAWARE
| ||||||||
| Number of Shares Beneficially Owned by Each Reporting Person With: |
| ||||||||
| 11 | Aggregate amount beneficially owned by each reporting person
452,153.00 | ||||||||
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)
![]() | ||||||||
| 13 | Percent of class represented by amount in Row (11)
6.0 % | ||||||||
| 14 | Type of Reporting Person (See Instructions)
PN |
SCHEDULE 13D
|
| CUSIP No. | 046513206 |
| 1 |
Name of reporting person
Redmile Strategic Long Only Trading Sub, Ltd. | ||||||||
| 2 | Check the appropriate box if a member of a Group (See Instructions)
(a)
(b)
| ||||||||
| 3 | SEC use only | ||||||||
| 4 |
Source of funds (See Instructions)
WC | ||||||||
| 5 |
Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)
![]() | ||||||||
| 6 | Citizenship or place of organization
CAYMAN ISLANDS
| ||||||||
| Number of Shares Beneficially Owned by Each Reporting Person With: |
| ||||||||
| 11 | Aggregate amount beneficially owned by each reporting person
376,377.00 | ||||||||
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)
![]() | ||||||||
| 13 | Percent of class represented by amount in Row (11)
5.0 % | ||||||||
| 14 | Type of Reporting Person (See Instructions)
CO |
SCHEDULE 13D
|
| Item 1. | Security and Issuer |
| (a) | Title of Class of Securities:
Common Stock, par value $0.0001 per share |
| (b) | Name of Issuer:
Atara Biotherapeutics, Inc. |
| (c) | Address of Issuer's Principal Executive Offices:
1280 Rancho Conejo Blvd, Thousand Oaks,
CALIFORNIA
, 91320. |
| Item 2. | Identity and Background |
| (a) | This Amendment No. 1 to Schedule 13D amends and supplements the Schedule 13D filed with the SEC on May 23, 2025 (the "Prior Schedule 13D") to reflect the addition of Redmile Strategic Long Only Trading Sub, Ltd. ("Redmile Long Only").
Redmile Long Only became a reporting person solely as a result of an increase in the aggregate number of the Issuer's outstanding Common Stock, which increased the number of shares of Common Stock issuable to Redmile Long Only upon exercise of certain pre-funded warrants to purchase Common Stock under the beneficial ownership limitation. The Reporting Persons have not engaged in any transactions since the Prior Schedule 13D. Capitalized terms used but not defined in this Amendment No. 1 shall have the meanings set forth in the Prior Schedule 13D. Except as specifically amended by this Amendment No. 1, the Prior Schedule 13D is unchanged.
Item 2(a) of the Prior Schedule 13D is hereby amended and restated in its entirety as follows:
This Schedule 13D is being filed jointly by Redmile Group, LLC ("Redmile"), Jeremy C. Green, RedCo I, L.P. ("RedCo I"), Redmile Biopharma Investments II, L.P. ("RBI II"), and Redmile Long Only (collectively with Redmile, Mr. Green, RedCo I and RBI II, the "Reporting Persons"), pursuant to the provisions of Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), as separate persons and not as members of a group. See Exhibit 99.1 to this Schedule 13D for their Joint Filing Agreement. |
| (b) | Item 2(b) of the Prior Schedule 13D is hereby amended and restated in its entirety as follows:
Redmile:
One Letterman Drive
Building D, Suite D3-300
The Presidio of San Francisco
San Francisco, California 94129
Jeremy C. Green:
c/o Redmile Group, LLC (NY Office)
45 W. 27th Street, Floor 11
New York, NY 10001
RedCo I:
c/o Redmile Group, LLC
One Letterman Drive
Building D, Suite D3-300
The Presidio of San Francisco
San Francisco, California 94129
RBI II:
c/o Redmile Group, LLC
One Letterman Drive
Building D, Suite D3-300
The Presidio of San Francisco
San Francisco, California 94129
Redmile Long Only:
c/o Redmile Group, LLC
One Letterman Drive
Building D, Suite D3-300
The Presidio of San Francisco
San Francisco, California 94129 |
| (c) | Item 2(c) of the Prior Schedule 13D is hereby amended and restated in its entirety as follows:
Redmile: investment manager/adviser to certain private investment vehicles
Jeremy C. Green: managing member of Redmile
RedCo I: private investment fund
RBI II: private investment fund
Redmile Long Only: private investment fund |
| (f) | Item 2(f) of the Prior Schedule 13D is hereby amended and restated in its entirety as follows:
Redmile: Delaware
Jeremy C. Green: United Kingdom
RedCo I: Delaware
RBI II: Delaware
Redmile Long Only: Cayman Islands |
| Item 5. | Interest in Securities of the Issuer |
| (a) | Item 5(a) of the Prior Schedule 13D is hereby amended and restated in its entirety as follows:
The aggregate amount of shares of Common Stock that may be deemed beneficially owned by the Reporting Persons is comprised of (i) 441,701 shares of Common Stock held by the Redmile Funds, including the 191,226 shares of Common Stock directly held by RedCo I, the 142,631 shares of Common Stock directly held by RBI II and the 66,855 shares of Common Stock directly held by Redmile Long Only, and (ii) in each case subject to the Beneficial Ownership Blocker, 3,412,843 shares of Common Stock issuable upon exercise of certain pre-funded warrants to purchase Common Stock (the "Warrants"), including the 156,216 shares of Common Stock issuable upon exercise of the Warrants directly held by RedCo I, the 2,054,155 shares of Common Stock issuable upon exercise of the Warrants directly held by RBI II, and the 827,581 shares of Common Stock issuable upon exercise of the Warrants directly held by Redmile Long Only. Redmile is the investment manager to the Redmile Funds and, in such capacity, exercises voting and investment power over all of the shares held by the Redmile Funds and may be deemed to be the beneficial owner of these shares. Jeremy C. Green serves as the managing member of Redmile and also may be deemed to be the beneficial owner of these shares. Redmile and Mr. Green each disclaims beneficial ownership of these shares, except to the extent of its or his pecuniary interest in such shares, if any.
Pursuant to the terms of the Warrants, the Issuer may not effect any exercise of the Warrants, and a holder of a Warrants does not have the right to exercise the Warrants held by such holder, to the extent that after giving effect to such issuance after exercise, the holder (together with the holder's affiliates, and any other persons acting as a group together with the holder or any of the holder's affiliates), would beneficially own in excess of 9.99% (the "Beneficial Ownership Limitation") of the number of shares of Common Stock outstanding immediately after giving effect to the issuance of shares of Common Stock issued upon exercise of the Warrant (the "Beneficial Ownership Blocker"). The Beneficial Ownership Limitation may be changed at a holder's election upon 61 days' notice to the Issuer.
The 751,223 shares of Common Stock reported as beneficially owned by Redmile and Mr. Green in this Schedule 13D represent 9.99% of the outstanding shares of Common Stock. The 347,442 shares of Common Stock reported as beneficially owned by RedCo I in this Schedule 13D represent 4.7% of the outstanding shares of Common Stock. The 452,153 shares of Common Stock reported as beneficially owned by RBI II in this Schedule 13D represent 6.0% of the outstanding shares of Common Stock. The 376,377 shares of Common Stock reported as beneficially owned by Redmile Long Only in this Schedule 13D represent 5.0% of the outstanding shares of Common Stock.
For purposes of this Schedule 13D, the percent of class for each Reporting Person, other than RedCo I, was calculated based on sum of: (i) 7,210,235 shares of Common Stock outstanding as of November 6, 2025, as reported by the Issuer in its Form 10-Q for the quarterly period ended September 30, 2025 filed with the SEC on November 12, 2025 (the "Form 10-Q"), plus (ii) 309,522 shares of Common Stock issuable upon exercise of the Warrants directly held by the Redmile Funds, which due to the Beneficial Ownership Limitation is the maximum number of shares that could be issued upon exercise of those Warrants. The percent of class for RedCo I was calculated based on sum of: (i) 7,210,235 shares of Common Stock outstanding as of November 6, 2025, as reported by the Issuer in its Form 10-Q, plus (ii) 156,216 shares of Common Stock issuable upon exercise of the Warrants directly held by RedCo I, which due to the Beneficial Ownership Limitation is the maximum number of shares that could be issued upon exercise of those Warrants. |
| (b) | Item 5(b) of the Prior Schedule 13D is hereby amended and restated in its entirety as follows:
Redmile:
(1) Sole Voting Power: 0
(2) Shared Voting Power: 751,223
(3) Sole Dispositive Power: 0
(4) Shared Dispositive Power: 751,223
Jeremy C. Green:
(1) Sole Voting Power: 0
(2) Shared Voting Power: 751,223
(3) Sole Dispositive Power: 0
(4) Shared Dispositive Power: 751,223
RedCo I:
(1) Sole Voting Power: 0
(2) Shared Voting Power: 347,442
(3) Sole Dispositive Power: 0
(4) Shared Dispositive Power: 347,442
RBI II:
(1) Sole Voting Power: 0
(2) Shared Voting Power: 452,153
(3) Sole Dispositive Power: 0
(4) Shared Dispositive Power: 452,153
Redmile Long Only:
(1) Sole Voting Power: 0
(2) Shared Voting Power: 376,377
(3) Sole Dispositive Power: 0
(4) Shared Dispositive Power: 376,377 |
| (e) | RedCo I ceased to be a 5% beneficial owner when the Issuer reported the increase in its outstanding Common Stock in its Form 10-Q filed on November 12, 2025. |
| Item 7. | Material to be Filed as Exhibits. |
Exhibit 99.3: Joint Filing Agreement, dated as of November 14, 2025, by and among Redmile, Jeremy C. Green, RedCo I, RBI II and Redmile Long Only. |
| SIGNATURE | |
After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.
|
|
|
|
|
|
|
|
|
|
|
(a)