try this??
my $ST=$DB->prepare("call apps.package_name.proc(?, ?, ?)");
my ($ST_result, $arg1, $arg2);
...
$ST->bind_param(1, $arg1);
$ST->bind_param(2, $arg2);
$ST->bind_param_inout(3, \$ST_result, 0, { ora_type=>ORA_RSET } );
$ST->execute();
while (my $hr = $ST_result.fetchrow_hashref) {
... process data ...
}