Notifiable share interest in Theravance, Inc.

Notifiable Share Interest in Theravance, Inc.

GlaxoSmithKline plc ("GSK") announces that on 3 May 2011 GSK purchased 261,299 shares of Common Stock of Theravance, Inc. ("Theravance") at a price of $25.60 per share, for a total investment of $6,689,254.40. These shares were purchased from Theravance pursuant to GSK's right to acquire, on a quarterly basis, sufficient shares of common stock to maintain its ownership percentage in Theravance, taking into account the preceding quarter's net option exercise and equity vesting activity.

GSK's interest in Theravance now comprises 6,163,577 shares of Common Stock and 9,401,499 shares of Class A Common Stock, which together represent approximately 19.01% of Theravance's outstanding capital stock. The calculation is based on a total of 81,878,356 shares of Common Stock and Class A Common Stock outstanding in Theravance after this transaction. This purchase is disclosable and will be reported under the rules of the Securities and Exchange Commission.

Victoria Whyte

Company Secretary

4 May 2011