Is this what you are looking for?

#!/usr/bin/perl

use strict;

my $count = 0;
while( <DATA> ) {
    $count = 1 if ( /\</ );
    $count = 0 if ( /^{/ );
    print if ( $count == 0 );
}


__DATA__
hello
 EVITE LA ENFERMEDAD PERIODONTAL<
EVITE LA ENFERMEDAD PERIODONTAL<                   AS
{IT}CTIQUE LA HIGIENE DENTAL PARA CUIDAR SUS ENCĂ
test
test
[download]