This Tender Offer Statement on Schedule TO relates solely to preliminary communications made before the
commencement of a planned tender offer by Flying Tigers Acquisition Corporation, a Delaware corporation (“Purchaser”) and a wholly owned subsidiary of Eli Lilly and Company, an Indiana corporation (“Lilly”), for all of the
outstanding shares of common stock of Adverum Biotechnologies, Inc., a Delaware corporation (the “Company”), pursuant to the Agreement and Plan of Merger, dated as of October 24, 2025 (the “Merger Agreement”), among
Lilly, Purchaser and the Company.
In connection with the proposed acquisition of the Company, Lilly will cause Purchaser to commence a tender offer for
all of the outstanding shares of common stock of the Company. The tender offer has not yet commenced. This filing is for informational purposes only, is not a recommendation and is neither an offer to purchase nor a solicitation of an offer to sell
any securities, nor is it a substitute for the tender offer materials that Lilly and Purchaser will file with the United States Securities and Exchange Commission (the “SEC”) upon commencement of the tender offer. A solicitation and
offer to buy outstanding shares of the Company will only be made pursuant to the tender offer materials that Lilly and Purchaser intend to file with the SEC. At the time the tender offer is commenced, Lilly and Purchaser will file tender offer
materials on Schedule TO, and the Company will file a solicitation/recommendation statement on Schedule 14D-9 (the “Solicitation/Recommendation Statement”) with the SEC with respect to the tender
offer. THE TENDER OFFER MATERIALS (INCLUDING AN OFFER TO PURCHASE, A RELATED LETTER OF TRANSMITTAL AND CERTAIN OTHER TENDER OFFER DOCUMENTS) AND THE SOLICITATION/RECOMMENDATION STATEMENT WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED
ACQUISITION AND THE PARTIES THERETO. INVESTORS AND STOCKHOLDERS OF THE COMPANY ARE URGED TO READ THESE DOCUMENTS CAREFULLY WHEN THEY BECOME AVAILABLE (AND EACH AS IT MAY BE AMENDED OR SUPPLEMENTED FROM TIME TO TIME) BECAUSE THEY WILL CONTAIN
IMPORTANT INFORMATION THAT INVESTORS AND STOCKHOLDERS OF THE COMPANY SHOULD CONSIDER BEFORE MAKING ANY DECISION REGARDING TENDERING THEIR SHARES OF COMMON STOCK IN THE TENDER OFFER. The tender offer materials (including the Offer to Purchase and the
related Letter of Transmittal), as well as the Solicitation/Recommendation Statement, will be made available to all stockholders of the Company at no expense to them at Lilly’s website at investor.lilly.com and (once they become available)
will be mailed to the stockholders of the Company free of charge. The information contained in, or that can be accessed through, Lilly’s website is not a part of, or incorporated by reference in, this filing. The tender offer materials
(including the Offer to Purchase and the related Letter of Transmittal), as well as the Solicitation/Recommendation Statement, will also be made available for free on the SEC’s website at www.sec.gov. In addition to the Offer to Purchase, the
related Letter of Transmittal and certain other tender offer documents, as well as the Solicitation/Recommendation Statement, Lilly and the Company file annual, quarterly and current reports, proxy statements and other information with the SEC. You
may read any reports, statements or other information filed by Lilly and the Company with the SEC for free on the SEC’s website at www.sec.gov.
Cautionary Statement Regarding Forward-Looking Statements
This filing contains forward-looking statements regarding Lilly’s proposed acquisition of the Company, regarding prospective benefits of the proposed
acquisition and the Company’s gene editing programs for retinal disease, regarding potential contingent consideration amounts and terms, regarding the anticipated occurrence, manner and timing of the proposed tender offer and the closing of
the proposed acquisition, regarding the Company’s cash runway and prospects, regarding the potential availability of financing to the Company under the Promissory Note (the “Promissory Note”) that the Company has entered into with
Lilly in conjunction with the proposed acquisition, regarding the Company’s product candidates and ongoing clinical and preclinical development, and regarding Lilly’s development of programs for ophthalmology and advancement of gene
therapies. All statements other than statements of historical fact are statements that could be deemed forward-looking statements. Forward-looking statements involve inherent risks and uncertainties, including with respect to consummating the
proposed acquisition and any competing offers or acquisition proposals for the Company, drug research, development and commercialization, the Company’s prospects, uncertainties as to how many of the Company’s stockholders will tender
their stock in the tender offer, the effects of the proposed acquisition (or the announcement thereof) on the Company’s stock price, relationships with key third parties or governmental entities, regulatory changes and developments, the impact
of global macroeconomic conditions, including trade and other global disputes and interruptions, including related to tariffs, trade protection measures, and similar restrictions, transaction costs, risks that the proposed acquisition