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Biota Pharmaceuticals, Inc. (NASDAQ:BOTA) today announced that it has completed the sale of assets related to its broad spectrum antibiotic program to a newly formed subsidiary of Spero Therapeutics, LLC, a Cambridge-based biopharmaceutical company founded to develop novel therapies for the treatment of bacterial infections. Financial terms of the transaction were not disclosed.

“This transaction gives us the opportunity to economically benefit from the antibiotic assets in our infectious disease portfolio and to fully focus our resources on our clinical-stage direct antiviral programs aimed at addressing infections with limited therapeutic options,” said Joseph Patti, Ph.D., president and chief executive officer of Biota. “We are pleased that the investigation of this early stage antibiotic program will be continued by Spero, an organization with significant expertise in the development of anti-infectives.”

“Spero is continuing to pioneer new approaches to treat serious infections. As we look to advance our programs into the clinic, these assets from Biota will support our mission of finding innovative treatments for serious bacterial infections,” said Ankit Mahadevia, M.D., Co-founder and Chief Executive Officer of Spero.

About Biota Pharmaceuticals, Inc.

Biota Pharmaceuticals is focused on the discovery and development of direct-acting antivirals to treat infections that have limited therapeutic options and affect a significant number of patients globally. The Company has three product candidates in active clinical development. These include: vapendavir, an oral treatment for human rhinovirus infections in moderate-to-severe asthmatics, currently being evaluated in the Company's ongoing Phase 2b SPIRITUS trial; BTA585, an oral fusion protein inhibitor in Phase 2 development for the treatment and prevention of respiratory syncytial virus infections; and BTA074, a topical antiviral treatment in Phase 2 development for condyloma caused by human papillomavirus types 6 & 11. For additional information about the Company, please visit www.biotapharma.com.

About Spero

Spero is a biopharmaceutical company developing a pipeline of novel treatments for bacterial infections and is located in Cambridge, Massachusetts. The company’s pipeline of anti-infective agents is one of the most unique in the industry. Spero is pioneering an entirely new therapeutic platform called the Potentiator; this approach has yielded multiple molecules that enhance the utility and potency of many classes of existing drugs to include Gram-negative organisms. Spero’s DHFR program is exploring the expansion of a novel antifolate’s antibacterial spectrum to treat trimethoprim resistance isolates including Gram-negative pathogens. The investors in Spero include Atlas Ventures, SR One, MRL Ventures, Lundbeckfond Ventures, The Kraft Group, Osage Partners and The Partners Innovation Fund. For more information, please visit www.sperotherapeutics.com

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 that involve known and unknown risks and uncertainties concerning Biota's business, operations and financial performance. Any statements that are not of historical facts may be deemed to be forward-looking statements, including the potential efficacy of the Company's three programs in the clinic. Various important factors could cause actual results, performance, events or achievements to materially differ from those expressed or implied by forward-looking statements contained elsewhere in this press release and in our Annual Report on Form 10-K, Quarterly Report on Form 10-Q and our other reports filed with the Securities and Exchange Commission. There may be events in the future that the Company is unable to predict, or over which it has no control, and the Company's business, financial condition, results of operations and prospects may change in the future. The Company may not update these forward-looking statements more frequently than quarterly unless it has an obligation under U.S. Federal securities laws to do so.

Biota is a registered trademark of Biota Pharmaceuticals, Inc.

Contacts:

Mark ColonneseExecutive Vice President and Chief Financial OfficerBiota Pharmaceuticals, Inc.(678) 221-3381m.colonnese@biotapharma.com

Beth DelGiaccoStern Investor Relations, Inc.(212) 362-1200beth@sternir.com