Development of a valid bioassay is delaying three studies of ImutecCorp.'s Virulizin, and commercial registration of the small moleculemacrophage activator in Mexico, the company said Wednesday.

"With the experts we brought in, along with our in-house capabilities,we should be able to get this resolved quickly," Wayne Cockburn,Imutec's vice president of corporate development, told BioWorld. Hesaid the Toronto company hopes to have the matter resolved in amatter of months.

Virulizin is a biological response modifier extracted from bovinereticuloendothelium, and was the basis for the formation of thecompany in 1986. Imutec already had received approval to start aPhase III trial in Canada of Virulizin in pancreatic cancer, and aPhase I/II trial in Kaposi's sarcoma.

The company has completed Phase II testing in Mexico in malignantmelanoma, and has filed for approval there. But Imutec must takecare of the bioassay situation before the drug can be marketed,Cockburn said. In the U.S., Imutec plans to run a Phase I/II test ofVirulizin in pancreatic cancer when the bioassay matter is resolved.

The bioassay is used as a release specification for manufacturing.Cockburn said it shows that the same product is being manufacturedeach time.

"It became apparent the bioassay we were using was measuringsomething we felt was not clinically relevant," Cockburn said. "Wepulled the application [for the Canadian study] to develop moreclinically relevant bioassays." - Jim Shrine

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