By Aaron Lorenzo

Several years after entering into a collaboration, there appears to be some light at the end of the tunnel for Amgen Inc. and NPS Pharmaceuticals Inc.

The companies began a Phase III trial of an investigational calcimimetic, AMG 073, to treat secondary hyperparathyroidism, a serious disorder associated with renal disease.

The trial triggers $6 million in milestone payments to NPS, with half that amount from Amgen. The other $3 million payment came from Kirin Brewery Co. Ltd., of Tokyo, which has Asian rights.

The Salt Lake City-based company originally received $43.5 million from Amgen for the former¿s calcium receptor technology. (See BioWorld Today, Dec. 29, 1995.)

¿This is really the second-generation calcimimetic to be brought forward,¿ NPS Chief Executive Hunter Jackson said. ¿The original [compound] that Amgen was focused on . . . was ultimately replaced with AMG 073, which is another NPS compound, but with better bioavailabity and metabolism properties. So that accounts for [the time from the original deal to date]. In the usual pharmaceutical timeline, it¿s not out of bounds by any means.¿

Part of a class of orally active compounds known as calcimimetics, AMG 073 increases the sensitivity of the calcium-sensing receptor on the surface of the parathyroid gland. It inhibits the secretion of excessive amounts of parathyroid hormone.

A timeline and other details for the new study were not released. But Phase II data, first presented at the American Society of Nephrology meeting earlier this year, supported moving the product into Phase III.

¿Amgen has executed a very thorough Phase II program,¿ Jackson said. ¿Generally speaking, what has been presented have been very consistent data showing that the compound appears to lower parathyroid hormone levels effectively. And it also lowers the calcium phosphate product as compared to controls, and that seems as though it may be important in limiting the mineralization of soft tissue that is currently thought by many to be responsible for some of the myocardial infarctions suffered by renal failure patients.¿

Secondary hyperparathyroidism is characterized by enlargement of the parathyroid glands and elevated circulating levels of parathyroid hormone.

Amgen will manufacture the drug if it reaches the commercialization stage. But for now, the transition to Phase III marks a milestone for Thousand Oaks, Calif.-based Amgen.

¿This is the first small molecule that Amgen has gotten into Phase III, so we¿re excited about that,¿ Amgen spokeswoman Rebecca Hamm said. ¿There is a pretty good-sized patient population that isn¿t currently being treated for secondary hyperparathyroidism. We see AMG 073 as being a very good potential treatment in the future for these patients.¿

¿There are about another $20 million in milestone payments left between the two partners between now and approval, or the NDA,¿ Jackson said.

Amgen¿s stock (NASDAQ:AMGN) gained 17 cents Friday to close at $57.97. NPS¿s stock (NASDAQ:NPSP) gained 34 cents to close at $38.98.