UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the Month of September 2021

Commission File Number: 001-38547

Autolus Therapeutics plc

(Translation of registrant’s name into English)

The MediaWorks

191 Wood Lane

London W12 7FP

United Kingdom

(Address of principal executive office)

Forest House

58 Wood Lane

White City

London W12 7RZ

United Kingdom

(Former address)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

☒  Form 20-F            ☐  Form 40-F

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):  ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7):  ☐

INCORPORATION BY REFERENCE

This Report on Form 6-K (the “Report”) and Exhibit 99.1 to this Report shall be deemed to be incorporated by reference into the registration statements on Form F-3 (File No. 333-232690), Form F-3 (File No. 333-258556) and Form S-8 (File No. 333-226457) of Autolus Therapeutics plc (including any prospectuses forming a part of such registration statements) and to be a part thereof from the date on which this Report is furnished, to the extent not superseded by documents or reports subsequently filed or furnished.

INFORMATION CONTAINED IN THIS REPORT ON FORM 6-K

Appointment of New Director

On September 15, 2021, Autolus Therapeutics plc (the “Company”) announced that, upon the recommendation of its Nominating and Corporate Governance Committee (the “Nominating Committee”) of the Company’s Board of Directors (the “Board”), the Board appointed John H. Johnson to serve as a Class II director of the Company and as chair of the Board, effective September 15, 2021. Mr. Johnson will serve for an initial term expiring at the Company’s 2023 annual meeting of stockholders, and until his successor has been duly elected and qualified, or until his earlier death, resignation or removal.

Concurrently with the appointment of Mr. Johnson as director and as an independent chair, Dr. Martin Murphy will resign as the current chair of the Board, and Mr. John Berriman will resign as lead independent director of the Board, each effective September 15, 2021. Dr. Murphy and Mr. Berriman will continue to serve as directors of the Board.

Mr. Johnson will be compensated in accordance with the terms of the Company’s non-executive director compensation policy, which has been amended in September 2021 to reflect an updated annual retainer for a non-executive chair and an updated initial equity award for a non-executive chair. Pursuant to the policy amended as of September 2021, Mr. Johnson will be entitled to receive a £50,000 annual retainer for his service as non-executive chair of the Board.

Further, pursuant to the policy amended as of September 2021, in connection with Mr. Johnson’s appointment as non-executive chair of the Board, he will also be granted an initial, one-time equity award of options to purchase 50,000 of the Company’s American Depositary Shares (“ADSs”) representing its ordinary shares, with an exercise price equal to the closing price of the Company’s ADSs on September 15, 2021, the date of his appointment. The initial option award to the chairperson has been increased compared to the initial equity award granted to other new non-executive directors, for whom the initial option award remains at 25,000 of the Company’s ADSs.

The award will vest and become exercisable in equal monthly installments through the third anniversary of Mr. Johnson’s date of appointment to the Board, subject to his continued service to the Company through each applicable vesting date. The Company also entered into its standard deed of indemnity agreement for directors and officers with Mr. Johnson, the form of which was filed as an exhibit to the Company’s Registration Statement on Form F-1 (File No. 333- 224720) filed with the SEC on June 8, 2018.

There are no arrangements or understandings between Mr. Johnson and any other persons pursuant to which Mr. Johnson was appointed as a director, and there are no related-party transactions in which Mr. Johnson has an interest requiring disclosure.

On September 15, 2021, the Company issued a press release announcing the aforementioned changes to the Board which is furnished as Exhibit 99.1 to this Report.

EXHIBIT LIST

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Exhibit 99.1

Autolus Therapeutics announces the appointment of John H. Johnson as non-executive chairman of its Board of Directors

LONDON, September 15, 2021 — Autolus Therapeutics plc (Nasdaq: AUTL), a clinical-stage biopharmaceutical company developing next-generation programmed T cell therapies, today announced that John H. Johnson has been appointed as non-executive chairman of its Board of Directors, effective September 15, 2021. Dr. Martin Murphy, who previously served as chairman, will continue to serve as a non-executive Board member.

Mr. Johnson brings to Autolus more than 30 years of experience in the life science industry. He is currently chief executive officer and a director of Strongbridge Biopharma plc, a NASDAQ listed commercial stage biopharmaceutical company. He previously served as the executive chairman of the company from November 2019 to July 2020, and as chairman from March 2015 to November 2019. He is a recognized leader in the biopharmaceutical industry and has held executive, operations and commercial leadership roles at Eli Lilly & Company, ImClone, Johnson & Johnson, and Pfizer. He also currently serves as a member of the Board of Directors of Verastem, Inc and Axogen, Inc. Mr. Johnson previously served on the Board of Directors of Pharmaceutical Research and Manufacturers of America (PhRMA), the Health Section Governing Board of Biotechnology Industry Organizations (BIO), BioNJ and holds a BS from the East Stroudsburg University of Pennsylvania.

“We are entering an exciting time in Autolus’ evolution as we progress obe-cel towards pivotal data and the expectation that obe-cel could become the first stand-alone therapy with curative potential for adult acute lymphoblastic leukemia (ALL) patients,” said Dr. Christian Itin, chief executive officer of Autolus. “Together with the entire board and management team I am delighted to welcome John as chairman of our Board. John’s experience in leading oncology-focused commercial-stage biopharmaceutical businesses will be invaluable as we start preparing for a successful outcome of the ongoing pivotal FELIX study of obe-cel.”

“I am delighted to serve as chairman of Autolus at such an important time in the Company’s development,” said John H. Johnson. “I am confident in Autolus’ ability to deliver its first pivotal data for its lead program in 2022 and am excited to work closely with the Board and Autolus’ experienced senior management team to develop therapies that may offer cancer patients substantial benefits over existing standards of care.”

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About Autolus Therapeutics plc

Autolus is a clinical-stage biopharmaceutical company developing next-generation, programmed T cell therapies for the treatment of cancer. Using a broad suite of proprietary and modular T cell programming technologies, the company is engineering precisely targeted, controlled and highly active T cell therapies that are designed to better recognize cancer cells, break down their defense mechanisms and eliminate these cells. Autolus has a pipeline of product candidates in development for the treatment of hematological malignancies and solid tumors. For more information please visit www.autolus.com.

About Obe-cel

Obe-cel is a CD19 CAR T cell investigational therapy designed to overcome the limitations in clinical activity and safety compared to current CD19 CAR T cell therapies. Designed to have a fast target binding off-rate to minimize excessive activation of the programmed T cells, Obe-cel may reduce toxicity and be less prone to T cell exhaustion, which could enhance persistence and improve the ability of the programmed T cells to engage in serial killing of target cancer cells. In collaboration with our academic partner, UCL, Obe-cel is currently being evaluated in a Phase 1 clinical trial in adult ALL and B-NHL. The company has also progressed Obe-cel to the FELIX study, a potential pivotal study.

About Obe-cel FELIX study

The FELIX Phase 1b/2 clinical trial is enrolling adult patients with relapsed / refractory ALL. The trial has a short Phase 1b component prior to proceeding to a single arm Phase 2 clinical trial. The primary endpoint is overall response rate, and the key secondary endpoints include duration of response, MRD negative CR rate and safety. The trial will enroll approximately 100 patients across 30 of the leading academic and non-academic centers in the United States, United Kingdom and Europe.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements are statements that are not historical facts, and in some cases can be identified by terms such as “may,” “will,” “could,” “expects,” “plans,” “anticipates,” and “believes.” These statements include, but are not limited to, statements regarding the future clinical development, efficacy, safety and therapeutic potential of obe-cel, including progress, expectations as to the reporting of data, conduct and timing and potential future clinical activity and milestones; expectations regarding the initiation, design and reporting of data from clinical trials. Any forward-looking statements are based on management’s current views and assumptions and involve risks and uncertainties that could cause actual results, performance, or events to differ materially from those expressed or implied in such statements. These risks and uncertainties include, but are not limited to, the risks that Autolus’ preclinical or clinical programs do not advance or result in approved products on a timely or cost effective basis or at all; the results of early clinical trials are not always being predictive of future results; the cost, timing and results of clinical trials; that many product candidates do not become approved drugs on a timely or cost effective basis or at

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all; the ability to enroll patients in clinical trials; possible safety and efficacy concerns; and the impact of the ongoing COVID-19 pandemic on Autolus’ business. For a discussion of other risks and uncertainties, and other important factors, any of which could cause Autolus’ actual results to differ from those contained in the forward-looking statements, see the section titled “Risk Factors” in Autolus’ Annual Report on Form 20-F filed with the Securities and Exchange Commission on March 4, 2021, as well as discussions of potential risks, uncertainties, and other important factors in Autolus’ subsequent filings with the Securities and Exchange Commission. All information in this press release is as of the date of the release, and Autolus undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events, or otherwise, except as required by law.

Contacts:

Lucinda Crabtree, PhD

Vice President, Business Strategy and Planning

+44 (0) 7587 372 619

l.crabtree@autolus.com

Julia Wilson

+44 (0) 7818 430877

j.wilson@autolus.com

Susan A. Noonan

S.A. Noonan Communications

+1-212-966-3650

susan@sanoonan.com

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