Hi,
I don't think so your condition will work.to exclude or include values based on the Pattern functions are not available in the filter conditions.
My filters conditions syntax is based on the Native Filter type not by Business filter type check-box.
if you are not comfortable with Native filters syntax then create one more object in business layer based on the Case Type Desc.
Object Case Type.
Select part=substring(@Select(class name\Case Type Desc;1;3)
With this you will get the first three letters.
After that create filter and use newly created Case Type object not equal to OIS. (Don't put star after OIS).Next to filter definition tab->click Properties tab select the option "use filter as mandatory in query" & "Apply on universe".
Amit