GlaxoSmithKline has extended its tender offer to acquire all of the outstanding shares of Human Genome Sciences for $13.00 per share in cash to 5:00 p.m. EST on July 20, 2012.

The newest extension allows four extra days on top of the deadline set by HGS for submission of definitive acquisition proposals in its strategic alternatives review process—July 16. GSK's tender offer was due to expire June 29, an extension of GSK's original private proposal on April 11. GSK believes the three months that will have passed since the start of this process is more than adequate time for the HGS board to bring it to completion.

Extension of the tender offer to July 20 will provide HGS shareholders the opportunity to evaluate the outcome of the HGS board's process relative to GSK's offer. Based on circumstances at that time, GSK will consider all available options regarding its offer but can make no assurance that the tender offer will be further extended. As GSK has clearly stated, the company remains willing to meet and review its offer with HGS at any time.

GSK's offer, which is not conditioned on due diligence or financing, represents a premium of 81% to HGS's closing share price of $7.17 on April 18, the last trading day before HGS publicly disclosed GSK's private offer. GSK's offer reflects the value of Benlysta, darapladib, albiglutide, HGS's operating and financial assets and expected cost synergies of at least $200 million. For HGS shareholders, it provides immediate liquidity at a substantial premium while eliminating further exposure to the significant execution risk inherent in HGS achieving its future growth objectives.

Given its near 20-year relationship with HGS and ownership of 50% of Benlysta as well as the vast majority of the economics associated with albiglutide and darapladib, GSK continues to believe it is uniquely positioned to deliver on the opportunity of the proposed combination.

The closing of the tender offer is subject to the terms and conditions detailed in the amended tender offer documents as filed on Schedule TO with the SEC on May 10 and May 23. Except for the extension of the tender offer expiration date, all other terms and conditions of the offer remain unchanged.