BEDMINSTER, N.J.--(BUSINESS WIRE)--NPS Pharmaceuticals, Inc. (NASDAQ: NPSP), a specialty pharmaceutical company developing orphan therapeutics for rare gastrointestinal and endocrine disorders, today announced that the company intends to retire the 15.5% Secured Class B Notes when they become redeemable at par value on September 30, 2011. The company also announced that it has entered into an agreement with Amgen that becomes effective after the retirement of the Class B Notes. Under the Amgen agreement, Amgen will advance $145 million of Sensipar®/Mimpara® (cinacalcet HCl) royalties to NPS. After the repayment of the royalty advance and a 9 percent per annum discount factor on the balance of the advance, Amgen will resume paying royalties to NPS. The repayment of the royalty advance and discount shall be satisfied solely by Amgen’s withholding of royalties and except in the event of default, NPS will have no obligation to repay any unsettled amount.