Salix moving headquarters back to North Raleigh

Salix Pharmaceuticals is moving its headquarters back to North Raleigh.

The company said in a regulatory filing this week that it has signed an 11-year lease for 126,926 square feet of space at the Colonnade office park off Six Forks Road. The move is expected to happen this fall.

In 2005, Salix left the Colonnade for Duke Realty's Perimeter Park in Morrisville, where it had been leasing 77,000 square feet.

Salix had been subleasing its old corporate headquarters, about 26,000 square feet, in the Colonnade. That lease, which was set to expire in April, has been extended and Salix will eventually take over that space as well.

The total value of the two leases is about $36 million.

The move means Salix is executing a $1.7 million termination fee on its lease with Duke Realty in Perimeter Park.

About 150 of Salix's 395 employees are in Morrisville.

But the company, which has been one of the Triangle's best-performing public companies over the last year, is poised for rapid growth as it has two potential billion dollar drugs.

Earlier this month Salix announced that it had agreed to buy the rights to Relistor, a drug that treats constipation in patients taking pain medicines.

Relistor had just $16 million in worldwide sales last year, but Salix thinks the drug has the potential for peak annual sales of a billion dollars. Relistor is an injected drug used in patients taking opioid painkillers, which often cause severe constipation.

Salix is also seeking U.S. Food and Drug Administration approval to market its best-selling drug, Xifaxan, for irritable bowel syndrome.

A hearing on the application is set for March 7.

If Xifaxan is approved to treat irritable bowel syndrome, Salix estimates it could bring $2.5 billion a year in sales.