Hello,
The current version of phpdocx only allows to remove placeholders (replacing them by empty strings) or clean a preset block using this method:
http://www.phpdocx.com/api-documentation/templates/delete-Word-template-block-content
Phpdocx 6 will add a new class to support adding, removing and replacing content dynamically in any part of the main document. For example you'll be able to remove a single or alls paragraphs that contain a full string or a placeholder.
Regards.