NEW YORK—NPS Pharmaceuticals Inc. will receive a one-time $25 million payment this month in exchange for its rights to receive royalties earned after 2018 for sales of its Sensipar drug under an amended license agreement with Amgen Inc reported NASDAQ.

Sensipar, marketed as Mimpara in Europe, treats secondary hyperparathyroidism in chronic kidney disease patients on dialysis. In 1996 NPS licensed world-wide rights to Amgen to develop and commercialize the drug, and the drug received FDA approval in March 2004.

NPS said funds from the agreement are expected to support the launches of both Gattex, a treatment for short bowel syndrome, and Natpara, which is intended to be used for adult hypoparathyroidism, in addition to aiding its transition into a self-sustaining commercial-stage business.

The deal is expected to accelerate cash flow with at least $75 million of incremental cash expected through 2013.

The amendment also extends the royalty-advance-repayment period, limiting the offset of the royalty advance that the biopharmaceutical company received from Amgen in August 2011 to $8 million a quarter.

After repayment of the advance and a 9 percent anum discount factor on the balance of $92 million, Amgen will resume paying NPS all royalties earned through 2018.

"This innovative transaction underscores our commitment to accessing capital at the lowest possible cost and in a manner that is in the best interests of our shareholders," said Luke M. Beshar, NPS's chief financial officer.

Shares of NPS were inactive in premarket trade at $8.61, while shares of Amgen slipped 0.2 percent to $72.75. NPS is up 31 percent so far this year, while Amgen is up 14 percent.

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