LOS ANGELES -- NeoRx Corp. of Seattle said its patentedrhenium-186 targeted radiotherapeutic was shown in animaltests to deliver twice the normal dose of radiation to targetedtumors while nearly halving the amount of unwanted radiationfound in the blood, where it causes bone marrow toxicity.

"These preclinical results demonstrate that NeoRx's pre-targeting technology can improve the therapeutic index in adramatic fashion," said John M. Reno, NeoRx's director ofresearch and product development, who presented study datato a meeting here of the Society of Nuclear Medicine. "Wecontinue to improve the technology, with the goal of achievinga tenfold increase in the therapeutic index."

Immunomedics Inc. of Morris Plains, N.J., reported Thursday tothe same meeting upbeat data from a 10-patient study of itsradio-labeled imaging agent, ImmuRAID, for detectinginfectious disease.

The company said that doses as small as a half-milligram coulddetect sites of bone, abdominal or sinus infections as early asan hour after injection, while exposing patients to less radiationthan the standard method of labeling white blood cells withindium.

No allergic antibody responses to the mouse protein (HAMA)were found in eight of the 10 patients analyzed a month later,Immunomedics said.

ImmuRAID reacts with certain white blood cells thataccumulate in sites of infection and uses a labeled technetium-99m that can be scanned using a conventional nuclear medicinecamera. Compared with existing method, Immunomedics'product eliminates the handling of blood and avoids the risk ofinfection to laboratory and medical personnel. The companysaid it plans to begin Phase III clinicals in the next few months.

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