In October 2007, we entered into a license agreement with Bristol-Myers Squibb (BMS) for the worldwide development and commercialization of AC480, a kinase inhibitor that selectively inhibits the HER family of receptors, HER1, HER2, HER3 and HER4. Under the agreement, we acquired an exclusive, worldwide, non-transferable license to exploit certain patents and other intellectual property related to AC480. We also maintain limited rights to sublicense AC480, subject to a right of first offer retained by BMS. Upon the completion of certain United States and international clinical development and regulatory milestones, we may be required to pay BMS up to a total of $62.0 million. Additionally, BMS is entitled to tiered royalty payments calculated as a percentage of net sales of licensed products. The royalty rate increases based on certain annual net sales thresholds.