To the shareholders of ADC Therapeutics SA Invitation to the Annual General Meeting Date and Time : Thursday

To the shareholders of ADC

Invitation to the Annual General Meeting

Date and Time: Thursday, June 30, 2022, at 7:30 a.m.

EDT / 1:30 p.m. CEST

Location: Headquarters of ADC

Therapeutics SA, Biop le, Route de la Corniche 3B, 1066 Epalinges, Switzerland (no physical shareholder attendance)

It is my great pleasure to write to you as the

new Chief Executive Officer of ADC Therapeutics. I am very impressed by the Company's numerous accomplishments to date under Chris

Martin's outstanding leadership and excited about the many opportunities ahead. The Company has a clear mission of delivering next-generation

PBD-based ADCs to improve the lives of patients affected by cancer, and this remains the driving force of everything we do.

2021 was an exceptional year for ADC Therapeutics,

during which the Company achieved significant business, regulatory and development milestones. The highlight of the year was our first

FDA approval of ZYNLONTA in April 2021 for patients with diffuse large B-cell lymphoma (DLBCL), just five short years

after dosing the first patient. It validated our proprietary antibody drug conjugate (ADC) platform and, importantly, introduced a new

treatment option to patients with significant medical need. We are pleased with the team's progress since launch in bringing ZYNLONTA

to patients, especially while navigating the challenging COVID environment.

Beyond the first approved indication, we are exploring

ZYNLONTA's potential to expand into earlier lines of therapy where additional treatment options are still needed. Our focused development

plan includes several ongoing and planned trials of ZYNLONTA as a combination with other therapies in DLBCL to ensure all patients with

lymphoma can receive the maximum benefit from ZYNLONTA.

Our second most advanced therapeutic candidate

is camidanlumab tesirine (Cami), a PBD-based ADC targeting CD25 for the treatment of Hodgkin lymphoma. Data from the pivotal Phase 2 trial

will be presented at the European Hematology Association Congress in June 2022 and anecdotal stories of late-line patients benefitting

from treatment have been truly inspiring to all of us. We are preparing to submit a Biologics License Application (BLA) to the FDA for

Beyond hematology, we are leveraging our ADC platform

for the development of our robust solid tumor portfolio, including three clinical programs and two preclinical programs. We are exploring

Cami in combination with pembrolizumab in a Phase 1b trial in solid tumors. ADCT-901 (targeting KAAG1) is a novel and potential first-in-class

therapy currently in a Phase 1 trial in solid tumors such as platinum-resistant ovarian cancer and triple-negative breast cancer. We are

also planning to initiate the Phase 1b combination study of ADCT-601 (targeting AXL) in multiple solid tumors in the first half of 2022.

In addition, we have a collaboration with the National Cancer Institute (NCI) for ADCT-701 (targeting DLK-1), which is focused on neuroendocrine

malignancies, and we are completing preclinical studies to enable the filing of an IND. Finally, our most recently announced solid tumor

program is ADCT-212 (targeting PSMA), which is in preclinical development to support an IND filing for metastatic prostate cancer.

As for other corporate and business updates, we

have substantial working capital to fund the commercialization of ZYNLONTA and to invest in our pipeline programs. To that end, last year

we completed a royalty financing agreement with HealthCare Royalty Partners for up to $325 million, including $225 million upfront and

up to $100 million in near term potential milestones. We are also committed to expanding our global reach to provide ZYNLONTA to as many

patients worldwide as possible. We are pleased that our Overland ADCT BioPharma joint venture is making good progress with the continued

enrollment of the pivotal trial in China, and we are making solid progress in our partnership with Mitsubishi Tanabe Pharmaceutical Corporation

for Japan which we announced earlier this year. Finally, we continue to advance our regulatory submission for ZYNLONTA in Europe.

We are committed to carrying out our mission in

a responsible, ethical, and sustainable manner that reflects our values and mirrors the innovation of our science. Earlier this year,

we launched our inaugural Environment, Social and Governance (ESG) report. It highlights the ways we are working to create and maintain

sustainable operations across our business as we are constantly striving to improve our practices. We believe these efforts will enable

us to best deliver novel ADCs to better the lives of patients.

Finally, I would like to thank all the employees

at ADC Therapeutics for their immense contributions in achieving these accomplishments in 2021 and for their dedication to delivering

novel treatment options to patients. I would also like to extend my gratitude to all the physicians and patients for their partnership

with the Company and to all our many stakeholders for their continued support. I am excited to have joined ADC Therapeutics at this exciting

time when we are well-positioned to execute on our objectives. We look forward to updating you on the continued progress of our innovative

programs and business over the weeks and months to come.

Chief Executive Officer

ADC Therapeutics Head Office | Route de

la Corniche 3B, 1066 Epalinges, Switzerland ADC Therapeutics America |430 Mountain Avenue, Suite #404. New Providence, NJ 07974, USA

Important notice regarding COVID-19

Please note that, in accordance with Swiss Covid-19

regulations, the Annual General Meeting of shareholders for 2022 will be held by proxy only. Company shareholders will not be permitted

to be physically present at the meeting, but can instead exercise their voting rights for the 2022 Annual General Meeting exclusively

by sending voting instructions in accordance with the voting instructions set out herein (please see section titled "Organizational

Information" at the end of this document).

We take the safety of our shareholders, directors,

officers, employees and service providers very seriously, and thank you for your understanding and the need for these measures.

Agenda and Proposals of the Board of Directors

The Board of Directors

proposes that the Management Report, the Annual Financial Statements and the Consolidated Financial Statements for the financial year

2021 be approved, and that the Auditors' Reports be acknowledged.

The Board of Directors

proposes that the members of the Board of Directors and the Executive Committee be discharged from liability for the financial year 2021.

The Board of Directors

proposes that the loss of the Company be carried forward as follows:

The Board of Directors proposes to renew

the Company's Authorized Share Capital by amending Article 4a, Paragraph 1 of the Articles of Association as follows (the proposed

amendments are underlined):

"The Board of Directors shall

be authorized to increase the share capital at any time, including in connection with an intended takeover, until June 30, 2024,

by a maximum amount of CHF 3,130,800 by issuing a maximum of 39,135,000 fully paid in registered shares with a par value of CHF 0.08

each. Increases in partial amounts shall be permissible."

The term of office for the Chairman and

all members of the Board of Directors expires at the end of the 2022 Annual General Meeting. The Board of Directors proposes the re-election

of Ron Squarer (Chairman), Stephen Evans-Freke, Michael Forer, Peter Hug, Christopher Martin, Viviane Monges, Thomas Pfisterer, Tyrell

Rivers, Victor Sandor, and Jacques Theurillat for a term of office until completion of the 2023 Annual General Meeting.

Peter B. Corr and Thomas Rinderknecht

have informed the Company that they do not wish to stand for re-election as members of the Board of Directors. Peter B. Corr has been

a member of the Board of Directors since 2011 and Thomas Rinderknecht since 2016. The Company wishes to extend Peter B. Corr and Thomas

Rinderknecht its sincerest thanks for their service.

Information on the professional background

of the Chairman and the other current members of the Board of Directors can be found in our 2021 Annual Report and at https://adctherapeutics.com/our-board-of-directors/.

The Board of Directors proposes to elect

Jean-Pierre Bizzari as a new member of the Board of Directors for a term of office until completion of the 2023 Annual General Meeting.

The Board of Directors intends to name

Jean-Pierre Bizzari, if elected, as a member of the Science &Technology Committee.

Biographical Information: Jean-Pierre

Bizzari, M.D., has been nominated to serve as a non-executive member of our Board of Directors. He is a member of the scientific advisory

board of France's National Cancer Institute and a board member of the European Organisation of Research and Treatment of Cancer.

From 2008 to 2015, Dr. Bizzari served as Executive Vice President, Group Head of Clinical Development Oncology at Celgene Corporation.

Prior to that, he held various senior clinical development positions at Sanofi S.A., Aventis and Rh ne-Poulenc. In addition to our

board of directors, Dr. Bizzari also serves as a member of the board of directors of Halozyme Therapeutics, Inc., Oxford BioTherapeutics

Limited, NETRIS Pharma SAS and Nordic Nanovector ASA, and previously served on the board of directors of Transgene S.A., Onxeo SA and

Compugen Limited. Dr. Bizzari holds an M.D. from Nice Medical School.

The Board of Directors proposes to elect