Target Therapeutics Inc. announced Tuesday that its GuglielmiDetachable Coil (GDC) system, an investigational medical deviceintended for the treatment of high-risk or inoperable cerebralaneurysms, may have contributed to ischemic stroke in someclinical trial subjects.

Target of Fremont, Calif., said its planned changes to the devicewill have a negative financial impact on the company.

As a result of the announcement, Target's stock (NASDAQ:TGET)tumbled 28 percent, or $5.75 a share, on Tuesday to close at$15 in heavy trading of nearly 1.2 million shares. Only 36,600shares were traded on Monday.

The company said that during clinical trials, evidence based onmagnetic resonance imaging (MRI) examinations done on a"limited number" of patients treated with the GDC indicated thepotential for the creation of small metallic particles duringelectrolytic detachment of the coil. Artifacts attributable tosuch particles have been observed in 13 patients, the companysaid, and two of the patients have experienced ischemicstrokes.

The presence of these metallic particles, along with pre-existingmedical conditions, may contribute to ischemic stroke, thecompany said.

Target said it believes it has identified potential enhancementsto the GDC technique and system that will eliminate thephenomenon, and it has begun testing these changes.

The company said it has contacted the FDA and will work withthe agency to "ensure the continuation of patient safetythroughout the duration of these clinical trials."

After reviewing the situation, Target's scientific advisory boardhas concluded that for patients with high-risk or inoperablecerebral aneurysms for which there is currently no therapeuticalternative, the decision to treat the patient with the GDCshould be left up to the physician.

The GDC is an electrically detached micro-coil that is designedto provide protection from an aneurysm rupture by filling thecavity of an aneurysm and promoting clotting.

The company filed a 510(k) marketing clearance for the devicewith FDA in November 1992.

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