REVENUE	12 Months Ended
Dec. 31, 2013
REVENUE
REVENUE	(13) REVENUE In 1997, the Company licensed its oral rotavirus strain to GlaxoSmithKline plc (Glaxo) and Glaxo assumed responsibility for all subsequent clinical trials and all other development activities. The Company's licensed-in the rotavirus strain that was used to develop Glaxo's Rotarix rotavirus vaccine in 1995 and owed a license fee of 30% to Cincinnati Children's Hospital Medical Center (CCH) on net royalties received from Glaxo. In May 2005, the Company entered into an agreement whereby an affiliate of Paul Royalty Fund II, L.P. (PRF) purchased a 70% interest in the net royalties the Company received on worldwide sales of Rotarix. In December 2012, the Glaxo agreement expired automatically upon the expiration of the last relevant patent right covered by the Glaxo agreement. The Company's retained interests in Rotarix net royalties which were not sold to PRF are recorded as product royalty revenue and a corresponding amount that is payable to CCH is recorded as royalty expense. Product royalty revenue and royalty expense related to the Company's retained interest in Rotarix was $2.3 million, $10.8 million and $9.1 million for the years ended December 31, 2013, 2012 and 2011, respectively.

(13) REVENUE

In 1997, the Company licensed its oral rotavirus strain to GlaxoSmithKline plc (Glaxo) and Glaxo assumed responsibility for all subsequent clinical trials and all other development activities. The Company's licensed-in the rotavirus strain that was used to develop Glaxo's Rotarix rotavirus vaccine in 1995 and owed a license fee of 30% to Cincinnati Children's Hospital Medical Center (CCH) on net royalties received from Glaxo. In May 2005, the Company entered into an agreement whereby an affiliate of Paul Royalty Fund II, L.P. (PRF) purchased a 70% interest in the net royalties the Company received on worldwide sales of Rotarix. In December 2012, the Glaxo agreement expired automatically upon the expiration of the last relevant patent right covered by the Glaxo agreement. The Company's retained interests in Rotarix net royalties which were not sold to PRF are recorded as product royalty revenue and a corresponding amount that is payable to CCH is recorded as royalty expense. Product royalty revenue and royalty expense related to the Company's retained interest in Rotarix was $2.3 million, $10.8 million and $9.1 million for the years ended December 31, 2013, 2012 and 2011, respectively.