Nabi Biopharmaceuticals announced the initiation of a phase-I/II clinical trial for two of the antigens in the PentaStaph vaccine candidate, which is now owned by GlaxoSmithKline Biologicals (GSK). As a result of the initiation of the trial, Nabi is eligible for and has invoiced GSK US$ 5 million for successful completion of this milestone due under the agreement governing Nabi's sale of PentaStaph (Pentavalent S aureus Vaccine) and related assets to GSK. This milestone payment was contingent on initiation of the phase-I clinical trial for two PentaStaph antigens that target the most virulent toxins produced by the bacteria.

PentaStaph was sold to GSK for a total consideration of US$ 46 million, including US$ 26 million associated with accomplishing four milestone tasks. The remaining US$ 21 million in payments contemplated in the transaction are associated with three milestones which the Company expects to complete within the next 14 months. These remaining milestones include completion of the phase-I trial, the successful transfer of specified materials and the successful transfer of technology. Nabi received a cash payment of US$ 21.5 million when the transaction closed in November 2009 that included US$ 20 million associated with the transaction close, US$ 1 million associated with the sale of a separate pre-clinical program for a vaccine against S.epidermedis and US$ 0.5 million as reimbursement for license fees and clinical materials previously manufactured for use in the phase-I trial.

"I am very pleased with our progress toward realizing the significant value of the PentaStaph asset sale," said Dr Raafat Fahim, president and chief executive officer of Nabi Biopharmaceuticals. "In one month since we successfully closed the transaction, we completed the first milestone under the sale agreement. We look forward to fully realizing the remaining US$ 21 million of milestone payments."

Nabi Biopharmaceuticals leverages its experience and knowledge in powering the immune system to develop products that target serious medical conditions in the areas of nicotine addiction and gram-positive bacterial infections.