The pattern (\S+) means "capture one ore more non-whitespace chars", so that captures H<2:0>,I<3:0>,<*2>P - you might want e.g.

if ($string =~ /^<\*(\d+)>([,\w]+)<(\d+):(\d+):(\d+)>$/) {
    print "Matched\n";
}
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But without more context, it's not possible to determine the most suitable regexp.