As far as I know, it is not possible.
What is it that you are trying to achieve? Is it about how to read the input data? Then you might want to think about how to find out if it is a number or not.
data want;
something = "-1.03";
if compress(something,"0123456789-.,","K") = something then do;
*It is numeric, then maybe do an input statment to remove decimal chars or what ever it is you want.;
end;
else do;
*It is numeric, just let it be.;
end;
*You might want to check for missing values, as in " " or ".". ;
run;
Is it about how to use the data once it is in the table?
data want;
something = "-1.03";
somethingElse = something * 10;
*This works, but you get a note in the log file.
NOTE: Character values have been converted to numeric values at the places given by: (Line):(Column).
Better not to use it this way if you can avoid it. Maybe combine it with the above code.;
run;