Exhibit 5.2

OPINION OF DAVIS POLK & WARDWELL LLP

August 6, 2024

ADC Therapeutics SA
Biopôle
Route de la Corniche 3B
1066 Epalinges
Switzerland

Ladies and Gentlemen:

ADC Therapeutics SA, a société anonyme organized under the laws of Switzerland (the “Company”), is filing with the Securities and Exchange Commission a Registration Statement on Form S-3 (the “Registration Statement”) for the purpose of registering under the Securities Act of 1933, as amended (the “Securities Act”), (a) common shares, par value CHF 0.08 per share (the “Common Shares”) of the Company; (b) the Company’s debt securities (the “Debt Securities”), which may be issued pursuant to an indenture to be entered into between the Company and the trustee to be named therein (the “Trustee”) (the “Indenture”); (c) warrants of the Company (the “Warrants”), which may be issued pursuant to one or more warrant agreements to be entered into between the Company and the warrant agent to be named therein (the “Warrant Agent”) (each such warrant agreement, a “Warrant Agreement”); (d) purchase contracts (the “Purchase Contracts”), which may be issued pursuant to one or more purchase contract agreements to be entered into between the Company and the purchase contract agent to be named therein (the “Purchase Contract Agent”) (each such purchase contract agreement, a “Purchase Contract Agreement”); (e) units (the “Units”), which may be issued pursuant to one or more unit agreements to be entered into among the Company, a bank or trust company, as unit agent (the “Unit Agent”), and the holders from time to time of the Units (each such unit agreement, a “Unit Agreement”); and (f) subscription rights (the “Rights”), which may be issued pursuant to one or more subscription rights agreements to be entered into between the Company and the subscription agent to be named therein (the “Rights Agent”) (each such subscription rights agreement, a “Rights Agreement”).

We, as your counsel, have examined originals or copies of such documents, corporate records, certificates of public officials and other instruments as we have deemed necessary or advisable for the purpose of rendering this opinion.

In rendering the opinions expressed herein, we have, without independent inquiry or investigation, assumed that (i) all documents submitted to us as originals are authentic and complete, (ii) all documents submitted to us as copies conform to authentic, complete originals, (iii) all documents filed as exhibits to the Registration Statement that have not been executed will conform to the forms thereof, (iv) all signatures on all documents that we reviewed are genuine, (v) all natural persons executing documents had and have the legal capacity to do so, (vi) all statements in certificates of public officials and officers of the Company that we reviewed were and are accurate and (vii) all representations made by the Company as to matters of fact in the documents that we reviewed were and are accurate.

Based upon the foregoing, and subject to the additional assumptions and qualifications set forth below, we advise you that, in our opinion:

1. When the Indenture and any supplemental indenture to be entered into in connection with the issuance of any Debt Securities have been duly authorized, executed and delivered by the Trustee and the Company; the specific terms of a particular series of Debt Securities have been duly authorized and established in accordance with the Indenture; and such Debt Securities have been duly authorized, executed, authenticated, issued and delivered in accordance with the Indenture and the applicable underwriting or other agreement against payment therefor, such Debt Securities will constitute valid and binding obligations of the Company, enforceable in accordance with their terms, subject to applicable bankruptcy,

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insolvency and similar laws affecting creditors’ rights generally, concepts of reasonableness and equitable principles of general applicability, and may be subject to possible judicial or regulatory actions giving effect to governmental actions or foreign laws affecting creditors’ rights, provided that we express no opinion as to (w) the enforceability of any waiver of rights under any usury or stay law, (x) the effect of fraudulent conveyance, fraudulent transfer or similar provision of applicable law on the conclusions expressed above, (y) the validity, legally binding effect or enforceability of any section of the Indenture that requires or relates to adjustments to the conversion rate at a rate or in an amount that a court would determine in the circumstances under applicable law to be commercially unreasonable or a penalty or forfeiture or (z) the validity, legally binding effect or enforceability of any provision that permits holders to collect any portion of stated principal amount upon acceleration of the Debt Securities to the extent determined to constitute unearned interest.

2. When the Warrant Agreement to be entered into in connection with the issuance of any Warrants has been duly authorized, executed and delivered by the Warrant Agent and the Company; the specific terms of the Warrants have been duly authorized and established in accordance with the Warrant Agreement; and such Warrants have been duly authorized, executed, issued and delivered in accordance with the Warrant Agreement and the applicable underwriting or other agreement against payment therefor, such Warrants will constitute valid and binding obligations of the Company, enforceable in accordance with their terms, subject to applicable bankruptcy, insolvency and similar laws affecting creditors’ rights generally, concepts of reasonableness and equitable principles of general applicability, and may be subject to possible judicial or regulatory actions giving effect to governmental actions or foreign laws affecting creditors’ rights.

3. When the Purchase Contract Agreement to be entered into in connection with the issuance of any Purchase Contracts has been duly authorized, executed and delivered by the Purchase Contract Agent and the Company; the specific terms of the Purchase Contracts have been duly authorized and established in accordance with the Purchase Contract Agreement; and such Purchase Contracts have been duly authorized, executed, issued and delivered in accordance with the Purchase Contract Agreement and the applicable underwriting or other agreement against payment therefor, such Purchase Contracts will constitute valid and binding obligations of the Company, enforceable in accordance with their terms, subject to applicable bankruptcy, insolvency and similar laws affecting creditors’ rights generally, concepts of reasonableness and equitable principles of general applicability, and may be subject to possible judicial or regulatory actions giving effect to governmental actions or foreign laws affecting creditors’ rights.

4. When the Unit Agreement to be entered into in connection with the issuance of any Units has been duly authorized, executed and delivered by the Unit Agent and the Company; the specific terms of the Units have been duly authorized and established in accordance with the Unit Agreement; and such Units have been duly authorized, executed, issued and delivered in accordance with the Unit Agreement and the applicable underwriting or other agreement against payment therefor, such Units will constitute valid and binding obligations of the Company, enforceable in accordance with their terms, subject to applicable bankruptcy, insolvency and similar laws affecting creditors’ rights generally, concepts of reasonableness and equitable principles of general applicability, and may be subject to possible judicial or regulatory actions giving effect to governmental actions or foreign laws affecting creditors’ rights.

5. When the Rights Agreement to be entered into in connection with the issuance of any Rights has been duly authorized, executed and delivered by the Rights Agent and the Company; the specific terms of the Rights have been duly authorized and established in accordance with the Rights Agreement; and such Rights have been duly authorized, executed, issued and delivered in accordance with the Rights Agreement and the applicable underwriting or other agreement against payment therefor, such Rights will constitute valid and binding obligations

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of the Company, enforceable in accordance with their terms, subject to applicable bankruptcy, insolvency and similar laws affecting creditors’ rights generally, concepts of reasonableness and equitable principles of general applicability, and may be subject to possible judicial or regulatory actions giving effect to governmental actions or foreign laws affecting creditors’ rights.

In connection with the opinions expressed above, we have assumed that, at or prior to the time of the delivery of any such security, (i) the Board of Directors of the Company shall have duly established the terms of such security and the Board of Directors of the Company and, to the extent required under Swiss law, the shareholders of the Company shall have duly authorized the issuance and sale of such security and such authorization shall not have been modified or rescinded; (ii) the Company is, and shall remain, validly existing as a corporation in good standing (to the extent such concept exists) under the laws of Switzerland; (iii) the Registration Statement shall have become effective and such effectiveness shall not have been terminated or rescinded; (iv) the Indenture, the Debt Securities, the Warrant Agreement, the Purchase Contract Agreement, the Unit Agreement and the Rights Agreement are each valid, binding and enforceable agreements of each party thereto (other than as expressly covered above in respect of the Company); and (v) there shall not have occurred any change in law affecting the validity or enforceability of such security. We have also assumed that the terms of any security whose terms are established subsequent to the date hereof and the issuance, execution, delivery and performance by the Company of any such security (a) are within its corporate powers, (b) do not contravene, or constitute a default under, the articles of association or other constitutive documents of the Company, (c) require no action by or in respect of, or filing with, any governmental body, agency or official and (d) do not contravene, or constitute a default under, any provision of applicable law or public policy or regulation or any judgment, injunction, order or decree or any agreement or other instrument binding upon the Company and (ii) any Warrant Agreement, Purchase Contract Agreement, Unit Agreement and Rights Agreement and any security issued pursuant to any such agreements will be governed by the laws of the State of New York.

We are members of the Bar of the State of New York and the foregoing opinion is limited to the laws of the State of New York and the federal laws of the United States. Insofar as the foregoing opinion involves matters governed by the laws of Switzerland, we have relied, without independent inquiry or investigation, on the opinion of Homburger AG delivered to you today.

We hereby consent to the filing of this opinion as an exhibit to the Registration Statement referred to above and further consent to the reference to our name under the caption “Legal Matters” in the prospectus, which is a part of the Registration Statement. In giving this consent, we do not admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act.

Very truly yours,

/s/ Davis Polk & Wardwell LLP

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