The Durham company said it has stopped development of a nasal spray for seasonal allergies because the treatment failed a late-stage clinical study, the first of two required for regulatory approval.

In January, Inspire scrapped a partnership with a Spanish company after an experimental allergy pill the companies were working on hit regulatory roadblocks.

That leaves Inspire with two chances to become profitable: Denufosol, a cystic fibrosis drug that has been in the works for more than a decade, and Prolacria, a dry-eye treatment that has been in regulatory limbo for more than two years. Both are in late-stage testing and at least two years from generating sales, if they are approved.

But Joseph Schwartz, a biotechnology analyst with Leerink Swann, said Inspire has plenty of cash to wait -- $140 million, according to filings with the Securities and Exchange Commission.

"It's not a big deal," Schwartz said about the loss of the nasal spray, known as epinastine.

The Triangle is rich with drug development companies that are far from generating profits. Inspire was expected to reach profitability in 2006, but it struggled to get one of its own drugs to market.

Facing widening losses, the company bought the rights to develop and market three drugs.

One of them, a pink-eye treatment called AzaSite, received regulatory approval in April 2007 and generated about $3 million in sales during its first six months on pharmacy shelves.

Inspire also had revenue from two drugs it sells for its partner, Allergan, which added to $48.7 million in total sales last year, according to SEC filings.

But Inspire remains unprofitable, and without the allergy drugs, it has two fewer chances to decrease losses.

That's the risk of drug development, Inspire spokeswoman Jenny Kobin said.

"You look for the opportunity, you try to come to a decision of go or no go as quickly as you can, and you act on it," Kobin said.

Halting development of epinastine will spare the money Inspire was spending on the nasal spray. According to Schwartz, the company had about 20 percent of its research-and-development budget dedicated to the drug.

"Cash is very precious," Kobin said. "We need to allocate it as wisely as we can."

Inspire shares fell 5 cents Wednesday to close at $3.53, the lowest level in more than five years. The stock has lost more than half of its value in the past year.