FDA asks Sonus for more information regarding EchoGen’s NDA amendment

Agency’s move will add additional delay to EchoGen’s review

Sonus Pharmaceuticals appears to be snakebit in trying to develop a better relationship with the Food and Drug Administration. The Bothell, WA, ultrasound contrast developer announced this month that the FDA has notified Sonus that its new drug application amendment for EchoGen is not complete. Sonus said this means additional delay of the agency’s review of the contrast agent.

Sonus’ marketing plans for EchoGen are already behind schedule following the FDA’s determination in February that the product’s new drug application was not approvable as filed (SCAN 3/18/98). Following discussions with the FDA, Sonus assembled an amendment to EchoGen’s NDA and submitted it to the agency in August (SCAN 9/2/98).

Sonus executives declined to speculate on why the FDA might have considered the NDA amendment incomplete, saying they needed to meet with the agency first to discuss the document. Industry analyst Alex Zisson of investment firm Hambrecht & Quist in New York City said that the FDA considers the NDA amendment incomplete because it does not include enough manufacturing information about the product. The agency wants information on EchoGen’s manufacturing specifications, as well as data on the shelf life of the product. Sonus already has studies under way addressing those issues, Zisson said.

The question now is whether the FDA will begin its review of EchoGen immediately, and accept the manufacturing data when they are complete, or postpone its review of EchoGen until the studies are finished.

“There could be no delay, or there could be a delay of several months,” Zisson said. “Sonus should have the data in a few months, and maybe they can get the FDA to start looking at the application before then. Or the FDA could adhere to the letter of the law and sit on the application until all the data come in.”

Sonus executives believe that the FDA’s action will result in a delay for EchoGen, but they’re not sure how long that delay will be until they meet with the agency. Such a meeting should take place shortly, according to Terry Willard, vice president of marketing and business development.

“It will cause a delay,” Willard said. “We’re not certain how much of a delay until we’ve met the FDA, which will be soon.”

At the time it received the February not-approvable letter, Sonus estimated that an FDA decision on EchoGen might not be rendered until as late as March 1999, assuming the agency takes a full six months to review the NDA amendment. This month’s news could push that date even further into the year.

The recent moves have many industry observers wondering whether the FDA is singling out Sonus for special treatment. In addition to the not-approvable letter, the agency in March issued a warning letter to the company for claims made in marketing literature about EchoGen (SCAN 4/15/98).

Sonus’ problems with the FDA began after the company and several other contrast firms filed suit against the FDA last year in an effort to change the way the agency was regulating Optison, a rival ultrasound contrast agent from Molecular Biosystems. Sonus and the other companies won that battle and were able to force the FDA to regulate Optison as a drug rather than as a device. But it may have been a Pyrrhic victory, given the difficulties Sonus has experienced in getting its own agent through the FDA.

The company’s ongoing struggles with the FDA are reflected in its stock price: The most recent FDA action prompted the company’s stock to drop 44% to close at $4.31. The company’s 52-week high was $42.50.