Medical Device Daily Washington Editor

Congress may have backed off the idea of scuttling FDA's pre-emption of state court lawsuits over adverse events that appear on the labels of drugs and medical devices, but state courts continue to hear such suits as judges increasingly issue rulings that overrule federal pre-emption.

Organon USA (Roseland, New Jersey) is the target of a series of 37 suits filed in New Jersey's Essex County Superior Court and a federal court in Newark for adverse events associated with NuvaRing, which in October 2001 became the first hormone-secreting contraceptive ring approved by FDA.

According to the New York Post, the suits allege that the NuvaRing caused blood clots that have led to amputations, pulmonary embolisms and death.

The product label does include warnings regarding embolisms and also indicates that the pivotal study "concluded that with the exception of oral contraceptive users age 35 and older who smoke and age 40 and older who do not smoke, mortality associated with all methods of birth control is low and below that associated with childbirth."

NuvaRing releases low doses of estrogen and progestin near the cervix and is said to be between 98% and 99% effective, comparable to the efficacy of most birth-control pills. The device, which is regulated by the Center for Drug Evaluation and Review at FDA, rather than the Center for Devices and Radiological Health, is approved in 14 European Union nations via a mutual recognition mechanism with the Netherlands serving as the reference state.

Organon hopes to make the NuvaRing available in more than 40 nations.

According to Steven Blau, a principal in the firm of Blau & Brown (Hackensack, New Jersey), in a statement said that NuvaRing is marketed "as a safe alternative to the [birth control] patch, and it's not." Blau said that he wants FDA to "take notice of the misrepresentation by the drug company with respect to the [NuvaRing's] safety and efficacy."

Organon spokesperson Frances DeSena is on record as saying that the device "is not hazardous" and that it has been "tested and proven for the FDA."

In an email statement sent to Medical Device Daily, Organon said that it had "recently received a number of lawsuits regarding our contraceptive vaginal ring NuvaRing from a single law firm that is actively soliciting clients through the Internet and now also through the media."

The action comes on the heels of a decision by Judge Eldon Fallon of the U.S. District Court of the Eastern District of Louisiana to deny a motion by Vioxx maker Merck (Whitehouse Station, New Jersey) to throw out lawsuits filed after the 2002 change to the label for Vioxx. That label change indicated that cardiovascular events were among the possible adverse events associated with the anti-inflammatory. But Fallon wrote that he found "FDA's current view on the question of immunity for prescription drug manufacturers … entirely unpersuasive."

Merck is said to be considering an appeal.

PET/CT false positives found

Researchers at the University of Texas Medical School (UTMS; Houston) have found evidence suggesting that the software used in an unspecified model of positron-emission tomography/computerized axial tomography (PET/CT) scanner may generate a false-positive rate of as much as 40%.

While the researchers have come up with a patch for the software, no such fix is currently commercially available.

In an article appearing in the June 15 issue of the Journal of Nuclear Medicine (JNM), K. Lance Gould, MD, professor of cardiology at UTMS, and five others noted that "cardiac PET combined with CT is rapidly expanding despite artifactual defects and false-positive results due to misregistration of PET and CT attenuation correction data - the frequency, cause, and correction of which remain undetermined."

Their data show that 103 of the 259 patients who participated in the study had false positive results.

Of the 259 patients, scans for 59 - a rate of 23% - indicated severe false abnormalities that indicated a need for immediate surgical intervention. "These falsely positive results could lead to unnecessary procedures for nonexistent heart problems or for problems that could be treated without surgery," Gould said.

Gould said that images of PET/CT, appropriately interpreted, produce "absolutely perfect images of blood flow in the heart" and are "the best way to assess and directly manage heart disease." He suggested that the misregistration problems he encountered were particularly severe for imaging of the front and side areas of the heart, which accounted for 76% of the 103 bad readings. The apex of the heart accounted for 8% of the false positives, and the lower portion was the source of the balance of 16% of the erroneous readings.

Gould also co-authored a 2004 paper appearing in JNM that examined a similar problem with PET cardiac imaging that involved misregistration "between attenuation and emission images caus[ing] artifactual abnormalities … that result in false-positive defects."

According to that article, scans for roughly 21% of 1,177 came back with false positives, with patient characteristics such as body mass index, displacement of the diaphragm and heart size correlating most often with the misregistrations.

The abstract from the current study indicates that the researchers were checking for myocardial perfusion with a 16-slice scanner that employed helical attenuation correction.

Despite the expense associated with such equipment, Gould said that the software involved fails to account for movement in the lungs and heart while the patient is breathing.

Many perfusion tests involve stress tests during the perfusion, which may involve running or walking on a treadmill. Gould said that the failure of the PET and CT images to align properly causes "the images [to] have big holes or gaps where the processing is incorrect," leading a diagnostician to conclude that the patient "has severe disease."

Gould crafted a fix for the software problem with Tinsu Pan, PhD, associate professor of imaging physics at the M.D. Anderson Cancer Center (Houston), consisting of a rewrite of the software to correct for breathing motions and bringing the PET and CT images into alignment.