UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D/A1

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO § 240.13d-1(a) AND AMENDMENTS THERETO FILED PURSUANT TO 240.13d-2(a) UNDER THE SECURITIES EXCHANGE ACT OF 1934

Pandion Therapeutics, Inc.

(Name of Issuer)

Common Stock, Par Value $0.001

(Title of Class of Securities)

698340 10 6

(CUSIP Number)

Victoria A. Whyte

(Name, Address and Telephone Number of Person
Authorized to Receive Notices and Communications)

April 1, 2021

(Date of Event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box. 

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See §240.13d-7 for other parties to whom copies are to be sent.

^* 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 disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act.

Item 1.  Security and Issuer.

This Amendment No. 1 to Schedule 13D (this “Statement”) amends and supplements the statement on Schedule 13D originally filed on August 3, 2020 (the “Schedule 13D”) with respect to the shares of common stock, par value $0.001 per share (the “Common Stock”) of Pandion Therapeutics, Inc., a Delaware corporation (the “Issuer”). The Issuer’s principal executive offices are located at 134 Coolidge Avenue, Watertown, MA 02472. Unless otherwise indicated, each capitalized term used but not defined herein shall have the meaning assigned to such term in the Schedule 13D.

Item 2.  Identity and Background.

The response set forth in Item 2 of the Schedule 13D is hereby amended by deleting Schedule 1 in its entirety and replacing it with Schedule 1 attached.

Item 4.  Purpose of Transaction.

Item 4 is hereby superseded and replaced to read in full as follows:

The Reporting Person tendered 2,248,304 shares of Common Stock pursuant to the Offer to Purchase all of the outstanding shares of Common Stock made by Panama Merger Sub, Inc. (“Purchaser”), a wholly-owned subsidiary of Merck-Sharp & Dohme Corp (“Merck”), pursuant to the Agreement and Plan of Merger dated as of February 24, 2021, by and among the Issuer, Merck and Purchaser (the “Merger Agreement”). On April 1, 2021, Purchaser merged with and into the Issuer, with the Issuer continuing as the surviving corporation and a wholly owned subsidiary of Merck (the “Merger”). At the effective time of the Merger (the “Effective Time”), the shares of Common Stock beneficially owned by the Reporting Person were canceled in exchange for $60.00 per share (the “Offer Price”) in cash, without interest and subject to any applicable withholding taxes.

Jill A. Carroll served as a director of the Issuer until the Effective Time. Ms. Carroll was an employee of GlaxoSmithKline LLC, an indirect, wholly-owned subsidiary of the Reporting Person until September 14, 2020 and was a Principal at GSK Equity Investments, Limited, formerly known as S.R. One, Limited (“GSK Eq Inv”), an indirect, wholly-owned subsidiary of the Reporting Person which directly held the Common Stock, until September 13, 2020. Ms. Carroll is currently a Partner of SR One Capital Management LP, an investment adviser that provides services to certain subsidiaries of the Reporting Person and is not itself a subsidiary of the Reporting Person.

Ms. Carroll held options exercisable for 13,997 shares of Common Stock (the “Options”) at an exercise price of $18.00 per share. The Options were issued in connection with her service as a director of the Issuer and Ms. Carroll is obligated to transfer any shares issued under these Options to GSK Eq Inv. Pursuant to the Merger Agreement, each outstanding option was cancelled and converted into the right to receive cash in an amount equal to the product of (i) the total number of shares of Common Stock subject to option immediately prior to the Effective Time, multiplied by (ii) the excess (if any), of (x) the Offer Price over (y) the exercise price payable per share of Common Stock underlying such option. Ms. Carroll is obligated to transfer such cash to GSK Eq Inv.

Item 5.  Interest in Securities of the Issuer.

The disclosure previously contained in Item 5 is hereby superseded and replaced to read as follows:

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.

Date: April 8, 2021

GLAXOSMITHKLINE PLC

By: /s/ Victoria A. Whyte

Name: Victoria A. Whyte
Title:    Authorized Signatory

       Schedule 1

Name	Business Address	Principal Occupation or Employment	Citizenship
Urs Rohner	980 Great West Road Brentford Middlesex, England TW8 9GS	Company Director	Swiss
Sir Jonathan Symonds	980 Great West Road Brentford Middlesex, England TW8 9GS	Chairman and Company Director	British