By Ilan Zipkin
& Kathryn Calkins
Staff Writers

Once or twice a year, companies announce that they have received "broad" patents covering some aspect of technology. But all broad patents are not created equal. Some - like an antibody patent issued to Protein Design Labs Inc. (PDLI, Mountain View, Calif.) in 1996 - are clearly so watertight that others line up to obtain licenses. Others - like a gene therapy patent issued to the NIH in 1995 and exclusively licensed to Genetic Therapy Inc. (Gaithersburg, Md.) - have not excited the same degree of interest.