Variants (mutants) of recombinant activated protein C (APC) or recombinant
protein C (prodrug, capable of being converted to APC) that have
substantial reductions in anticoagulant activity but that retain normal
levels of anti-apoptotic activity are provided. Two examples of such
recombinant APC mutants are KKK191-193AAA-APC and RR229/230M-APC. APC
variants and prodrugs of the invention have the desirable property of
being cytoprotective (anti-apoptotic effects), while having significantly
reduced risk of bleeding. The invention also provides a method of using
the APC variants or prodrugs of the invention to treat subjects who will
benefit from APC's cytoprotective activities that are independent of
APC's anticoagulant activity. These subjects include patients at risk of
damage to blood vessels or tissue in various organs caused, at least in
part, by apoptosis. At risk patients include, for example, those
suffering (severe) sepsis, ischemia/reperfusion injury, ischemic stroke,
acute myocardial infarction, acute or chronic neurodegenerative diseases,
or those undergoing organ transplantation or chemotherapy, among other
conditions. Methods of screening for variants of recombinant protein C or
APC that are useful in accordance with the invention are also provided.