declare
  v_sp  user_objects.object_name%type;
  v_p1  pls_integer := 1;
  v_p2  varchar2(3) := 'abc';
begin
  select sp_name
    into v_sp
    from t
   where ...;
 
  execute immediate 'begin ' || v_sp || '(:p1, :p2); end;' using v_p1, v_p2;
end;
/