• Adverum plans to attend and present data on ADVM-022 at the ASGCT 21^st Annual Meeting in Chicago, May 16-19, 2018
  Poster Title: AAV.7m8-aflibercept Provides Long-term Protection in a Non-human Primate Model of Wet Macular Degeneration Over One Year Post Intravitreal Vector Administration (#554)
  Time: Thursday, May 17, 2018, 5:15-7:15 pm CT
  Location: Hilton Chicago, Stevens Salon C & D

• Cash, cash equivalents and marketable securities were $247.0 million as of March 31, 2018, compared to $190.5 million as of December 31, 2017. In February 2018, Adverum raised $64.5 million in net proceeds from a public offering of common stock. This quarter-end cash position is expected to fund the three lead gene therapy programs through at least the end of 2019, including preliminary clinical data for at least two of these programs, and through the initial stage of scaling up manufacturing capabilities.
• Revenues, consisting of revenue from collaborative research, were $0.2 million for the three months ended March 31, 2018, compared to $0.5 million for the same period in 2017.
• Research and development expenses were $12.8 million for the three months ended March 31, 2018, compared to $9.1 million for the same period in 2017. This increase was due to an overall increase in research and development activities, including compensation and benefits, and material production costs for ADVM-022 and ADVM-053 as these programs advance toward Phase 1/2 clinical trials.
• General and administrative expenses were $5.4 million for the three months ended March 31, 2018, compared to $8.0 million for the same period in 2017. This decrease was primarily due to charges during the three months ended March 31, 2017, including termination costs associated with the company's master services agreement with Cornell and the litigation settlement expense.
• Net loss attributable to common stockholders was $17.2 million, or $0.30 per basic and diluted share, for the three months ended March 31, 2018, compared to $16.1 million, or $0.38 per basic and diluted share, for the same period in 2017.

About Adverum Biotechnologies, Inc.
Adverum is a clinical-stage gene therapy company targeting unmet medical needs in serious rare and ocular diseases. Adverum has a robust pipeline that includes product candidates designed to treat rare diseases alpha-1 antitrypsin (A1AT) deficiency and hereditary angioedema (HAE) as well as wet age-related macular degeneration (wAMD). Leveraging a next-generation adeno-associated virus (AAV)-based directed evolution platform, Adverum generates product candidates designed to provide durable efficacy by inducing sustained expression of a therapeutic protein. Adverum has collaboration agreements with Regeneron Pharmaceuticals to research, develop, and commercialize gene therapy products for ophthalmic diseases and Editas Medicine to explore the delivery of genome editing medicines for the treatment of inherited retinal diseases. Adverum's core capabilities include clinical development and in-house manufacturing expertise, specifically in process development and assay development. For more information please visit www.adverum.com.

Forward-looking Statements
Statements contained in this press release regarding events or results that may occur in the future are "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. Such statements include, but are not limited to, statements regarding Adverum's plans to report preliminary data from the ADVANCE study in the second half of 2018, plans to submit two INDs to the FDA for ADVM-022 in wAMD and ADVM-053 in HAE in the second half of 2018, plans to use the preliminary data from the ADVANCE study to inform next steps, statements under the caption "2018 Outlook - Planned Pipeline Milestones," and expectations as to the ability of its quarter-end cash position to fund the three lead gene therapy programs through at least the end of 2019 and through the initial stage of scaling up manufacturing capabilities, all of which are based on certain assumptions made by Adverum on current conditions, expected future developments and other factors Adverum believes are appropriate in the circumstances. Adverum may not consummate any plans or product or clinical development goals in a timely manner, or at all, or otherwise carry out the intentions or meet the expectations or projections disclosed in its forward-looking statements, and you should not place undue reliance on these forward-looking statements. Actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of various risks and uncertainties, which include, without limitation, the risk of a delay in the enrollment of patients in Adverum's clinical studies or in the manufacturing of products to be used in such clinical studies. Risks and uncertainties facing Adverum are described more fully in Adverum's periodic reports filed with the Securities and Exchange Commission (SEC), especially under the caption "Risk Factors" in its latest Annual Report on Form 10-K filed with the SEC on March 6, 2018. All forward-looking statements contained in this press release speak only as of the date on which they were made. Adverum undertakes no obligation to update such statements to reflect events that occur or circumstances that exist after the date on which they were made.