Commercial speech is one of the categories of speech that enjoys lesser protection under the First Amendment.
Two types of commercial speech in particular, are given less or null protection: false advertising, and misleading advertising. The justification is to protect the rights of consumers, and of other companies.
If Pizza Hut prints materials that are untruthful about Papa John's, then Pizza Hut is committing misleading advertising, because it is spreading false information about its direct competitor. In this scenario, Pizza Hut could easily sue Papa John's in court, and win the case.
