MREO Mereo BioPharma Group PLC

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 or 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of June, 2023

Commission File Number: 001-38452

MEREO BIOPHARMA GROUP PLC

(Translation of registrant’s name into English)

4^th Floor, One Cavendish Place,

London, W1G 0QF, United Kingdom

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F  ☒                 Form 40-F  ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):  ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7):  ☐

INFORMATION CONTAINED IN THIS REPORT ON FORM 6-K

On June 16, 2023, Dr. Denise Scots-Knight, Mereo BioPharma Group plc’s (the “Company”) Chief Executive Officer, purchased 200,000 American Depositary Shares (“ADSs”), each representing five ordinary shares, nominal value £0.003 per share, of the Company in open market transactions at an average price of approximately $1.42 per ADS. On June 22, 2023, Christine Fox, the Company’s Chief Financial Officer, purchased 10,000 ADSs in open market transactions at an average price of approximately $1.34 per ADS.

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, thereunto duly authorized.

Date: June 30, 2023