SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
MEI Pharma, Inc.
(Name of Issuer)
Common Stock, par value $0.00000002 per share (the "Shares")
(Title of Class of Securities)
55279B301
(CUSIP Number)
07/22/2025
(Date of Event Which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to which this Schedule is filed:
Rule 13d-1(b)
Rule 13d-1(c)
Rule 13d-1(d)
SCHEDULE 13G
CUSIP No.
55279B301
1
Names of Reporting Persons
Citadel Advisors LLC
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
DELAWARE
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
3,167,695.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
3,167,695.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
3,167,695.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
9.75 %
12
Type of Reporting Person (See Instructions)
IA, HC, OO
Comment for Type of Reporting Person: The percentages reported in this Schedule 13G are based upon 32,491,374 Shares outstanding comprised of (i) 29,879,755 Shares outstanding as of July 22, 2025 (according to the issuer's prospectus as filed with the Securities and Exchange Commission on July 23, 2025), (ii) 2,084,509 Shares issued to affiliates of the reporting persons upon the voluntary exercise of certain warrants held by affiliates of the reporting persons prior to the date hereof, and (iii) 527,110 Shares issuable upon conversion of certain warrants held by affiliates of the reporting persons. Except as described in the preceding sentence, all Shares for the holdings of the reporting persons reported in this Schedule 13G are as of the opening of the market on July 29, 2025. The applicable warrants are subject to terms that limit exercise, if, after such exercise, the holder and its affiliates and any member of a group with such holder and its affiliates would beneficially own more than 9.99% of the number of shares of Common Stock outstanding immediately after exercise.
SCHEDULE 13G
CUSIP No.
55279B301
1
Names of Reporting Persons
Citadel Advisors Holdings LP
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
DELAWARE
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
3,167,695.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
3,167,695.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
3,167,695.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
9.75 %
12
Type of Reporting Person (See Instructions)
HC, PN
SCHEDULE 13G
CUSIP No.
55279B301
1
Names of Reporting Persons
Citadel GP LLC
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
DELAWARE
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
3,167,695.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
3,167,695.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
3,167,695.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
9.75 %
12
Type of Reporting Person (See Instructions)
HC, OO
SCHEDULE 13G
CUSIP No.
55279B301
1
Names of Reporting Persons
Citadel Securities LLC
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
DELAWARE
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
78,193.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
78,193.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
78,193.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
0.24 %
12
Type of Reporting Person (See Instructions)
BD, OO
SCHEDULE 13G
CUSIP No.
55279B301
1
Names of Reporting Persons
Citadel Securities Group LP
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
DELAWARE
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
78,193.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
78,193.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
78,193.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
0.24 %
12
Type of Reporting Person (See Instructions)
HC, PN
SCHEDULE 13G
CUSIP No.
55279B301
1
Names of Reporting Persons
Citadel Securities GP LLC
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
DELAWARE
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
78,193.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
78,193.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
78,193.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
0.24 %
12
Type of Reporting Person (See Instructions)
HC, OO
SCHEDULE 13G
CUSIP No.
55279B301
1
Names of Reporting Persons
Kenneth Griffin
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
UNITED STATES
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
3,245,888.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
3,245,888.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
3,245,888.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
9.99 %
12
Type of Reporting Person (See Instructions)
HC, IN
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
MEI Pharma, Inc.
(b)
Address of issuer's principal executive offices:
9920 Pacific Heights Blvd., Suite 150 San Diego, CA, 92121
Item 2.
(a)
Name of person filing:
This Schedule 13G is being jointly filed by Citadel Advisors LLC ("Citadel Advisors"), Citadel Advisors Holdings LP ("CAH"), Citadel GP LLC ("CGP"), Citadel Securities LLC ("Citadel Securities"), Citadel Securities Group LP ("CALC4"), Citadel Securities GP LLC ("CSGP") and Mr. Kenneth Griffin (collectively with Citadel Advisors, CAH, CGP, Citadel Securities, CALC4 and CSGP, the "Reporting Persons") with respect to the Shares of the above-named issuer owned by Citadel CEMF Investments Ltd., a Cayman Islands limited company ("CCIL"), and Citadel Securities. Such owned Shares may include other instruments exercisable for or convertible into Shares.
Citadel Advisors is the portfolio manager for CCIL. CAH is the sole member of Citadel Advisors. CGP is the general partner of CAH. CALC4 is the non-member manager of Citadel Securities. CSGP is the general partner of CALC4. Mr. Griffin is the President and Chief Executive Officer of CGP, and owns a controlling interest in CGP and CSGP.
The filing of this statement shall not be construed as an admission that any of the Reporting Persons is the beneficial owner of any securities covered by the statement other than the securities actually owned by such person (if any).
(b)
Address or principal business office or, if none, residence:
The address of each of the Reporting Persons is 830 Brickell Plaza, Miami, Florida 33131.
(c)
Citizenship:
Each of Citadel Advisors, CGP, Citadel Securities and CSGP is organized as a limited liability company under the laws of the State of Delaware. Each of CALC4 and CAH is organized as a limited partnership under the laws of the State of Delaware. Mr. Griffin is a U.S. citizen.
(d)
Title of class of securities:
Common Stock, par value $0.00000002 per share (the "Shares")
(e)
CUSIP No.:
55279B301
Item 3.
If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)
Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)
Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)
Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)
Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)
An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)
An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)
A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)
A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)
A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)
A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution:
(k)
Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.
Ownership
(a)
Amount beneficially owned:
1. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC may be deemed to beneficially own 3,167,695 Shares.
2. Citadel Securities LLC may be deemed to beneficially own 78,193 Shares.
3. Each of Citadel Securities Group LP and Citadel Securities GP LLC may be deemed to beneficially own 78,193 Shares.
4. Mr. Griffin may be deemed to beneficially own 3,245,888 Shares.
(b)
Percent of class:
1. The number of Shares that each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC may be deemed to beneficially own constitutes 9.75% of the Shares outstanding.
2. The number of Shares that Citadel Securities LLC may be deemed to beneficially own constitutes 0.24% of the Shares outstanding.
3. The number of Shares that each of Citadel Securities Group LP and Citadel Securities GP LLC may be deemed to beneficially own constitutes 0.24% of the Shares outstanding.
4. The number of Shares that Mr. Griffin may be deemed to beneficially own constitutes 9.99% of the Shares outstanding.
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
1. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC: 0
2. Citadel Securities LLC: 0
3. Each of Citadel Securities Group LP and Citadel Securities GP LLC: 0
4. Mr. Griffin: 0
(ii) Shared power to vote or to direct the vote:
1. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC: 3,167,695
2. Citadel Securities LLC: 78,193
3. Each of Citadel Securities Group LP and Citadel Securities GP LLC: 78,193
4. Mr. Griffin: 3,245,888
(iii) Sole power to dispose or to direct the disposition of:
1. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC: 0
2. Citadel Securities LLC: 0
3. Each of Citadel Securities Group LP and Citadel Securities GP LLC: 0
4. Mr. Griffin: 0
(iv) Shared power to dispose or to direct the disposition of:
1. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC: 3,167,695
2. Citadel Securities LLC: 78,193
3. Each of Citadel Securities Group LP and Citadel Securities GP LLC: 78,193
4. Mr. Griffin: 3,245,888
Item 5.
Ownership of 5 Percent or Less of a Class.
Item 6.
Ownership of more than 5 Percent on Behalf of Another Person.
Not Applicable
Item 7.
Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
Not Applicable
Item 8.
Identification and Classification of Members of the Group.
Not Applicable
Item 9.
Notice of Dissolution of Group.
Not Applicable
Item 10.
Certifications:
By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.
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.
Citadel Advisors LLC
Signature:
/s/ Seth Levy
Name/Title:
Seth Levy, Authorized Signatory
Date:
07/29/2025
Citadel Advisors Holdings LP
Signature:
/s/ Seth Levy
Name/Title:
Seth Levy, Authorized Signatory
Date:
07/29/2025
Citadel GP LLC
Signature:
/s/ Seth Levy
Name/Title:
Seth Levy, Authorized Signatory
Date:
07/29/2025
Citadel Securities LLC
Signature:
/s/ Seth Levy
Name/Title:
Seth Levy, Authorized Signatory
Date:
07/29/2025
Citadel Securities Group LP
Signature:
/s/ Seth Levy
Name/Title:
Seth Levy, Authorized Signatory
Date:
07/29/2025
Citadel Securities GP LLC
Signature:
/s/ Seth Levy
Name/Title:
Seth Levy, Authorized Signatory
Date:
07/29/2025
Kenneth Griffin
Signature:
/s/ Seth Levy
Name/Title:
Seth Levy, attorney-in-fact*
Date:
07/29/2025
Comments accompanying signature: * Seth Levy is signing on behalf of Kenneth Griffin as attorney-in-fact pursuant to a power of attorney previously filed with the Securities and Exchange Commission, and hereby incorporated by reference herein. The power of attorney was filed as an attachment to a filing by Citadel Advisors LLC on Schedule 13G for Allakos Inc. on October 13, 2023.
An email has been sent to your address with instructions for changing your password.
There is no user registered with this email.
You have made too many password recovery requests. Please try again tomorrow.
Sign Up
To create a free account, please fill out the form below.
Thank you for signing up!
A confirmation email has been sent to your email address. Please check your email and follow the instructions in the message to complete the registration process. If you do not receive the email, please check your spam folder or contact us for assistance.
Welcome to our platform!
Oops!
Something went wrong while trying to create your new account. Please try again and if the problem persist, to receive support.
