FDA rejects Trex’s digital mammography system as not equivalent to analog units

TDMS application no longer under review by agency

Trex Medical’s commitment to digital mammography in the U.S. has been tested yet again. This month the Danbury, CT, company received more bad news about its Trex Digital Mammography System (TDMS) with word that the Food and Drug Administration has found TDMS not equivalent to analog mammography systems. The FDA’s letter is the latest occurrence in a frustrating saga for Trex, which began its efforts to obtain 510(k) approval for the system almost two years ago (SCAN Special Report 12/97).

Trex has been selling TDMS in Europe since last October, when it received the CE Mark (SCAN 10/14/98). But attempts to bring the unit to market in the U.S. have thus far been unsuccessful. Shortly after last year’s RSNA meeting, the FDA notified Trex that its system could not be approved. The agency outlined additional data analysis required for clearance, which the company subsequently submitted. In its Aug. 6 notification, however, the FDA informed Trex that the digital system is not substantially equivalent to screen-film mammography systems. As a result, the vendor’s 510(k) application is no longer under consideration by the agency.

In its letter to Trex, the FDA said that it has been developing alternatives to expedite digital mammography’s introduction into the market. The agency invited the company to meet to discuss these alternatives, as well as how best to use the data Trex has already collected. Trex representatives will meet with the FDA later this month to determine how to move forward, according to Bill Webb, president and CEO. Trex expects that the FDA will suggest design changes and request additional clinical data. Trex remains committed to digital mammography, however, and will continue to work closely with the FDA, Webb said.

Despite much anticipation, digital mammography has proven difficult to bring to the U.S. market. Industry confusion over FDAguidelines could be a factor: The FDA last year changed course in its protocols for digital systems, following criticism that the framework the agency uses to evaluate the efficacy of digital mammography is flawed.

At an August 1998 meeting between mammography experts and the FDA’s Radiological Device Panel, the agency requested feedback on its 1996 guidance, which require vendors to prove the equivalency of full-field digital images to film within a 90% to 95% correlation range (SCAN 9/16/98). Critics labeled this range unrealistic, citing the human variability between readings of the same film, and claimed that it is essentially impossible for vendors to comply with the guidance.

This policy may soon change, however. The FDA hopes to publish a new guidance for digital mammography next month, according to Bob Doyle, executive secretary of the Radiological Devices Panel and scientific reviewer in the FDA’s Center For Devices and Radiological Health’s Office of Device Evaluation. In the meantime, other vendors developing digital mammography systems, such as Fischer Imaging and GE Medical Systems, have continued to prepare data for their 510(k) applications.

Denver-based Fischer has completed clinical trials for its unit, SenoScan, and awaits the FDA’s new guidelines, according to Morgan Nields, president and CEO. SenoScan employs flat-panel technology provided by Hologic’s Direct Radiography Corp., with Fischer’s own slot scanning technology.

GE’s flat-panel-based Senographe 2000D is still under clinical investigation for the U.S. market, although in March the company received the CE Mark and began selling the system in Europe (SCAN 3/17/99). Trex’s latest setback doesn’t affect GE’s 510(k) application plans for its unit, according to the Milwaukee-based vendor, although the company declined to comment on when it expected to file with the FDA.

“We’re working closely with the FDA to ensure we understand their needs,” said Amy Holberg, marketing manager for breast imaging. “Trex’s position doesn’t affect our strategy, or alter (our application plans) in any way.”

The FDA letter wasn’t the only discouraging recent event for Trex. The vendor also posted disappointing results for its third quarter 1999 (end-July). Revenues decreased 12.5% during the quarter, coming in at $63.1 million compared with $72.1 million in third quarter 1998. The company sustained a net loss of $14.3 million, compared to net income of $5.6 million for the same period last year. Restructuring costs of $18.1 million were also taken in this quarter. Although Trex’s mammography system sales increased by 24% over the same period in the previous year, its breast-biopsy system sales decreased. The company expects to see benefits from its restructuring efforts during the next fiscal year, Webb said.