Avalanche Biotechnologies, Inc. Reports First Quarter 2016 Financial Results

Avalanche Biotechnologies, Inc. Reports First Quarter 2016 Financial Results

MENLO PARK, CA, May 6, 2016 Avalanche Biotechnologies, Inc. (Nasdaq: AAVL), a gene therapy company committed to discovering and developing novel

medicines for patients suffering from diseases with few or burdensome treatment options, today reported financial results for the quarter ended March 31, 2016.

With the announcement of our proposed transaction with Annapurna Therapeutics, the first quarter of 2016 marked a new direction for Avalanche. Our

development plans have expanded to include gene therapy programs targeting difficult to treat orphan diseases, said president and chief executive officer of Avalanche, Paul B. Cleveland. We expect to complete the transaction in the

second quarter, and plan to introduce a new name and ticker symbol to symbolize this change.

Our expanded pipeline will include a

first-in-human study of ANN-001 for A1AT deficiency, planned to begin later this year and a first-in-human study of ANN-002 for heredity angioedema, or HAE, estimated to initiate in 2017. With our combined resources and talent, we will have the

opportunity to build a leadership role in developing promising, new gene therapies in multiple disease areas, concluded Mr. Cleveland.

First Quarter Financial Results

About Avalanche Biotechnologies, Inc.

Avalanche is a gene therapy company committed to discovering and developing novel medicines that can offer potentially life-changing therapeutic benefit to

patients suffering from diseases with few or burdensome treatment options. Avalanche is leveraging its next generation adeno-associated virus (AAV)-based directed evolution platform to generate product candidates designed to provide durable efficacy

by inducing sustained expression of a therapeutic protein. With significant capabilities and expertise in vector optimization, process development and manufacturing, Avalanche seeks to discover and develop targets in ophthalmology and beyond. For

more information, please visit www.avalanchebiotech.com.

Safe Harbor Statements

Additional Information about the Proposed Transaction with Annapurna and Where to Find It

This announcement does not constitute a solicitation of any vote or approval. In connection with the proposed transaction with Annapurna, Avalanche filed a

definitive proxy statement with the Securities and Exchange Commission, or the SEC, on April 7, 2016, and the proxy statement was mailed to Avalanche stockholders on or about April 11, 2016. INVESTORS AND SECURITY HOLDERS OF AVALANCHE ARE

URGED TO READ THE PROXY STATEMENT BECAUSE IT CONTAINS IMPORTANT INFORMATION ABOUT AVALANCHE, ANNAPURNA AND THE PROPOSED TRANSACTION AND ISSUANCE OF AVALANCHE COMMON STOCK. The proxy statement and other relevant materials, and any other documents

filed by Avalanche with the SEC, may be obtained free of charge at the SEC web site at www.sec.gov. In addition, investors and security holders may obtain free copies of the documents filed with the SEC by Avalanche by directing a written request

to: Avalanche Biotechnologies, Inc., 1035 O Brien Drive, Suite A, Menlo Park, CA 94025, Attention: Investor Relations. Investors and security holders are urged to read the proxy statement and any other relevant materials filed with the SEC

before making any voting decision with respect to the issuance of Avalanche common stock and other matters relating to the proposed transaction.

Forward-Looking Statements

Statements contained

in this press release regarding matters that are not historical facts 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 the therapeutic potential of, and development plans for, our product candidates; the structure, timing and completion of our proposed transaction with Annapurna; our expectations regarding the capitalization, resources and ownership

structure of the combined company; our expectations regarding the sufficiency of the combined company s resources to fund the advancement of any development program or the completion of any clinical trial; the nature, strategy and focus of the

combined company; the safety, efficacy and projected development timeline and commercial potential of any product candidates; the executive officer and board structure of

the combined company; and the expectations regarding voting by Avalanche stockholders. Avalanche may not consummate the proposed transaction, or any plans or product development goals in a timely

manner, or at all, or otherwise carry out the intentions or meet the expectations or projections disclosed in our 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, risks and uncertainties associated with stockholder approval of the

issuance of Avalanche common stock and the ability to consummate the proposed transaction, the ability to project future cash utilization and reserves needed for contingent future liabilities and business operations, the availability of sufficient

resources for combined company operations and to conduct or continue planned development programs and the ability to successfully develop any of our or Annapurna s product candidates. Risks and uncertainties facing Avalanche are described more

fully in Avalanche s periodic reports filed with the SEC. All forward-looking statements contained in this press release speak only as of the date on which they were made. Avalanche undertakes no obligation to update such statements to reflect

events that occur or circumstances that exist after the date on which they were made.

AVALANCHE BIOTECHNOLOGIES, INC.

CONDENSED CONSOLIDATED BALANCE SHEETS

AVALANCHE BIOTECHNOLOGIES, INC.

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

(In thousands, except per share amounts)