The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

There is no CUSIP number assigned to the Ordinary Shares. CUSIP number 67022C106 has been assigned to the American Depositary Shares of the Company, which are quoted on the Nasdaq Global Select Market under the symbol “NCNA.” Each American Depositary Share represents 1 Ordinary Share.

Names of Reporting Persons.

Harvard Management Company, Inc.

Check the Appropriate Box if a Member of a Group

(a)  ☐        (b)  ☐

SEC Use Only

Citizenship or Place of Organization

Massachusetts

Number of

Shares

Beneficially

Owned by

Each

Reporting

Person

With:

Sole Voting Power

2,911,111 Ordinary Shares

Shared Voting Power

0

Sole Dispositive Power

2,911,111 Ordinary Shares

Shared Dispositive Power

0

Aggregate Amount Beneficially Owned by Each Reporting Person

2,911,111 Ordinary Shares

Check if the Aggregate Amount in Row (9) Excludes Certain Shares    ☐

Percent of Class Represented by Amount in Row (9)

9.033%¹

Type of Reporting Person

EP

Based on 32,226,458 Ordinary Shares outstanding as of December 31, 2018, as reported in the Issuer’s Form 20-F filed with the Securities and Exchange Commission (the “SEC”) on March 7, 2019.

Name of Issuer: NuCana plc

Address of Issuer’s Principal Executive Offices: 3 Lochside Way, Edinburgh EH12 9DT, United Kingdom

Name of Person Filing:

Address of Principal Business Office, or if None, Residence:

Citizenship: Massachusetts

Title of Class of Securities: Ordinary Shares, nominal value £0.04 per share (“Ordinary Shares”) represented by American Depositary Shares (“ADS”), each of which represents one Ordinary Share.

CUSIP Number: 67022C1062

IF THIS STATEMENT IS FILED PURSUANT TO SS.240.13d-1(b) OR 240.13d-2(b) OR (c), CHECK WHETHER THE PERSON FILING IS A:

☐ Broker or dealer registered under Section 15 of the Act (15 U.S.C. 78o).

☐ Bank as defined in Section 3(a)(6) of the Act (15 U.S.C. 78c).

☐ Insurance company as defined in Section 3(a)(19) of the Act (15 U.S.C. 78c).

☐ Investment company registered under Section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8).

☐ An investment adviser in accordance with ss.240.13d-1(b)(1)(ii)(E);

☒ An employee benefit plan or endowment fund in accordance with ss.240.13d-1(b)(1)(ii)(F);

☐ A parent holding company or control person in accordance with ss.240.13d-1(b)(1)(ii)(G);

☐ A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);

☐ 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);

☐ Group, in accordance with ss.240.13d-1(b)(1)(ii)(J).

OWNERSHIP.

Amount beneficially owned: 2,911,111 Ordinary Shares, represented by 2,911,111 ADS. The Ordinary Shares beneficially owned may be exchanged into ADS on a one-for one basis.

Percent of class: 9.033%

Number of shares as to which such person has:

Sole power to vote or to direct the vote: 2,911,111 Ordinary Shares (represented by 2,911,111 ADS)

Shared power to vote or to direct the vote: 0

Sole power to dispose or to direct the disposition of: 2,911,111 Ordinary Shares (represented by 2,911,111 ADS)

Shared power to dispose or to direct the disposition of: 0

OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS.

OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON.

IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY.

IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP.

NOTICE OF DISSOLUTION OF GROUP.

CERTIFICATIONS.