>perl -wMstrict -le
"my $body  = qr{ [[:upper:]\d]+      }xms;
 my $cdc   = qr{ CDC (?: _ $body){2} }xms;
 my $smr   = qr{ DDCSMR    $body     }xms;
 my $rmr   = qr{ DDCRMR    $body     }xms;
 my $valid = qr{ \A \s* (?: $cdc | $smr | $rmr) \s* \z }xms;
 while (<>) {
   chomp;
   last unless $_;
   printf qq{'$_' %svalid \n}, m{$valid} ? '' : 'IN';
   }
"
  CDC_
'  CDC_    ' INvalid
   CDC_1_ANSND
'   CDC_1_ANSND' valid
   CDC_ASD_ERTY
'   CDC_ASD_ERTY   ' valid
XYZZY
'XYZZY' INvalid
  DDCRMRA
'  DDCRMRA   ' valid
DDCSMR
'DDCSMR' INvalid