Mangrove Partners Sends Letter to Holders of Nabi Biopharma; Urges Vote Against Merger

Dear Fellow Stockholders: Your support in voting against the proposed merger (the "Transaction") between Nabi Biopharmaceuticals ("Nabi" or the "Company") and Biota Holdings Limited, a Melbourne, Australia company ("Biota") is crucial to defeating this value-destroying transaction. The Mangrove Partners Fund, L.P. and its affiliates ("Mangrove Partners") strongly oppose the proposed Transaction because it fails to return to Nabi's stockholders the underlying value of the Company's assets, a value that we believe to be as much as $2.40 per share in cash, while enriching Nabi executives at the expense of Nabi's stockholders. Mangrove Partners strongly opposes the proposed Transaction and Transaction Proposals because we believe that: the proposed Transaction is an inferior alternative to several readily available alternatives that provide for the return of substantially all of the cash on the Company's balance sheet to Nabi's stockholders; Nabi's stockholders are being asked to invest in a speculative Australian biotechnology company that has lost money for the past two years and where the future leadership is uncertain; and the interests of Nabi management and the Nabi Board are not aligned with the best interests of stockholders in connection with the proposed Transaction. In fact, Mangrove Partners believes the Transaction's primary purposes are (1) to secure substantial payments in the form of special VIP bonuses and change of control benefits for Nabi's executives and (2) to grant Nabi's CEO, Dr. Raafat Fahim, and Chairman, Dr. Geoffrey Cox, lucrative seats on the Board of Directors of the newly combined entity.