The class of equity security to which this statement on Schedule 13D relates is the common shares, par value CHF 0.08 per share (the “Common Shares”) of ADC Therapeutics SA (the “Issuer”), a Swiss corporation. The address of the principal executive offices of the Issuer is Biopôle, Route de la Corniche 3B, 1066 Epalinges, Switzerland.

(a) The persons filing this Schedule 13D (collectively, the “Reporting Persons”) are:

1.  A.T. Holdings II Sàrl (“A.T. Holdings II”)

2.  C.T. Phinco Sàrl (“C.T. Phinco”)

4.  Auven Therapeutics Holdings L.P. (“Auven Therapeutics”)

5.  Auven Therapeutics General L.P. (“Auven Therapeutics General”)

6.  Auven Therapeutics GP Ltd. (“Auven Therapeutics GP”)

7. Stephen Evans-Freke

8. Peter B. Corr

A.T. Holdings II received 1,900,000 Common Shares pursuant to the conversion on a one-for-one basis of Class A common shares of the Issuer effected immediately prior to the completion of the Issuer’s initial public offering.  In addition, A.T. Holdings II received an aggregate of 15,100,000 Common Shares pursuant to the conversion on a one-for-one basis of various classes of preferred shares of the Issuer effected immediately prior to the completion of the Issuer’s initial public offering. A.T. Holdings II also received 874,923 Common Shares from the Issuer as consideration for agreeing to convert the Class E preferred shares of the Issuer held by A.T. Holdings II immediately prior to the Issuer’s initial public offering.  Further, A.T. Holdings II purchased 395,000 Common Shares in the Issuer’s initial public offering that closed on May 19, 2020, at a purchase price of $19 per share. A.T. Holdings II used partial proceeds from the Credit and Security Agreement (the “Credit and Security Agreement”), dated as of April 27, 2020, by and among A.T. Holdings II, as Borrower, and Oaktree Fund Administration, LLC, as Agent, and the lenders from time to time party thereto, to purchase the 395,000 Common Shares purchased in the Issuer’s initial public offering.

A.T. Holdings II also beneficially owns 3,125 Common Shares held by a nominee, which were received by the nominee pursuant to the conversion on a one-for-one basis of Class A common shares of the Issuer and the conversion on a one-for-one basis of Class C preferred shares of the Issuer effected immediately prior to the completion of the Issuer’s initial public offering.

The Reporting Persons acquired beneficial ownership of the Common Shares reported herein for investment purposes.  Based on market conditions and other factors, and subject to the consent of the underwriters of the Issuer’s initial public offering pursuant to the terms of the Lock-Up Agreement (as defined in Item 6 below), if applicable, ADC Products may consider selling some or all of the Common Shares beneficially owned by it in the near term and use the proceeds from such sales to pay back loans made by A.T. Holdings II pursuant to the Loan Agreement (as defined in Item 6 below).

Stephen Evans-Freke and Peter B. Corr serve as directors on the Issuer’s Board of Directors (the “Board”).

The Reporting Persons and their representatives have, from time to time, engaged in, and expect to continue to engage in, discussions with members of management and the Board, other current or prospective shareholders, industry analysts, existing or potential strategic partners or competitors, investment and financing professionals, sources of credit and other third parties regarding a variety of matters relating to the Issuer, which may include, among other things, the Issuer's business, management, capital structure and allocation, corporate governance, Board composition and strategic alternatives and direction, and may take other steps seeking to bring about changes to increase shareholder value as well as pursue other plans or proposals that relate to or could result in any of the matters set forth in subparagraphs (a) through (j) of Item 4 of Schedule 13D.

(a) and (b) Items 7 through 11 and 13 of each of the cover pages of this Schedule 13D are incorporated herein by reference.

The disclosure in Items 3 and 4 is incorporated herein by reference.

Pursuant to the Credit and Security Agreement, A.T. Holdings II has pledged to the lenders party thereto all of the Common Shares beneficially owned by it or afterward acquired by it to secure the lending by such lenders to A.T. Holdings pursuant to the Credit and Security Agreement.

Pursuant to the Second Amendment Agreement, dated April 27, 2020, to the Loan Agreement, dated September 15, 2017, between ADC Products, as Borrower, and A.T. Holdings II, as Lender (the “Loan Agreement”), ADC Products has pledged to A.T. Holdings II all of the Common Shares beneficially owned by it or afterward acquired by it to secure the lending by A.T. Holdings II to ADC Products pursuant to the Loan Agreement.

A.T. Holdings II and ADC Products on May 12, 2020, entered into a Lock-Up Agreement (the “Lock-Up Agreement”) with Morgan Stanley & Co. LLC and BofA Securities, Inc., underwriters of the Issuer’s initial public offering, pursuant to which A.T. Holdings II and ADC Products agreed, subject to limited exceptions, not to offer, pledge, announce the intention to sell, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend, or otherwise dispose of, directly or indirectly, any Common Shares beneficially owned by them or enter into any swap or other agreement that transfers to another, in whole or in part, any of the economic consequences of ownership of Common Shares for a period from May 12, 2020, until 180 days after May 12, 2020 (the “Restricted Period”), without the prior written consent of Morgan Stanley & Co. LLC and BofA Securities, Inc. on behalf of the underwriters. The foregoing restrictions on transactions in Common Shares do not apply to transactions relating to Common Shares acquired in the Issuer’s initial public offering or in open market transactions after the completion of the initial public offering.  A.T. Holdings II and ADC Products also agreed that without the prior written consent of Morgan Stanley & Co. LLC and BofA Securities, Inc., they will not transfer, distribute or dispose of any Common Shares or securities convertible into Common Shares (other than those Common Shares or securities convertible into Common Shares for which such entity holds as nominee on behalf of equity incentive plan participants) to their partners, members, stockholders, beneficiaries or other equity holders, other than transfers, distributions or dispositions of any Common Shares to any investment fund that is controlled or managed in the same or substantially similar manner as Auven Therapeutics, and that they will not sell any Common Shares or securities convertible into Common Shares (other than those Common Shares or securities convertible into Common Shares for which such entity holds as nominee on behalf of equity incentive plan participants) prior to June 30, 2022 without the prior approval of Morgan Stanley & Co. LLC and BofA Securities, Inc., such approval not to be unreasonably withheld for any sales following the end of the Restricted Period. Morgan Stanley & Co. LLC and BofA Securities, Inc. may waive the requirements of the Lock-Up Agreement at any time in their sole discretion.