AVALANCHE BIOTECHNOLOGIES REPORTS FOURTH QUARTER AND FISCAL 2015

AVALANCHE BIOTECHNOLOGIES REPORTS FOURTH QUARTER AND FISCAL 2015 FINANCIAL RESULTS

MENLO PARK, CA, March 3, 2016 Avalanche Biotechnologies, Inc. (Nasdaq: AAVL), a gene therapy company committed to discovering and developing novel

medicines for patients suffering from chronic or debilitating disease, today reported financial results for the fourth quarter and year ended December 31, 2015.

2015 was a year of reorientation for Avalanche following our Phase 2a trial results for AVA-101, our lead program for wet AMD. The team has been

focusing on preclinical work designed to inform our decision on the best path forward in wet-AMD, enhancing and then applying our next-generation vector discovery platform to fuel an R&D pipeline, and continuing work under our collaboration with

Regeneron. We were also looking for opportunities to leverage our expertise and resources by identifying additional assets to bring into the company, said Paul B. Cleveland, president and chief executive officer of Avalanche. On

February 1 we announced a proposed combination with Annapurna Therapeutics, a gene therapy company with four product candidates in development, including a program for the potential treatment of alpha 1 antitrypsin deficiency which is expected

to be in the clinic by the end of this year and a candidate for the potential treatment of hereditary angioedema which is expected to be in the clinic in 2017. We believe that this transaction will transform Avalanche into a leading gene therapy

company with an extensive pipeline.

Fourth Quarter and Fiscal 2015 Financial Results

About Avalanche Biotechnologies, Inc.

gene therapy company committed to discovering and developing novel medicines that can offer potentially life-changing therapeutic benefit to patients suffering from chronic or debilitating disease. 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.

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

intends to file relevant materials with the Securities and Exchange Commission, or the SEC, including a proxy statement. INVESTORS AND SECURITY HOLDERS OF AVALANCHE ARE URGED TO READ THESE MATERIALS WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL

CONTAIN IMPORTANT INFORMATION ABOUT AVALANCHE, ANNAPURNA AND THE PROPOSED TRANSACTION AND ISSUANCE OF AVALANCHE COMMON STOCK. The proxy statement and other relevant materials (when they become available), 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 the other relevant materials when they become available before

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

Participants in the Solicitation

its directors and executive officers may be deemed to be participants in the solicitation of proxies from the stockholders of Avalanche in connection with the proposed transaction with Annapurna and common stock issuance. Information regarding the

special interests of these directors and executive officers in the proposed transaction will be included in the proxy statement referred to above. Additional information regarding the directors and executive officers of Avalanche is also included in

Avalanche s Annual Report on Form 10-K for the year ended December 31, 2014 and the proxy statement for Avalanche s 2015 Annual Meeting of Stockholders. These documents are available free of charge at the SEC web site at www.sec.gov

and from Investor Relations at Avalanche at the address set forth above.

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)