The Distinction Between Advertising and Other Activities, the Health Canada document which outlines what constitutes advertising, asks a series of questions to determine the nature of the activity. The author and distributor being a medical director in and of itself, does not, in and of itself, necessarily render a piece exempt from Federal advertising regulations, the PAAB Code, or PAAB preclearance. Please see PAAB Q&A 403. While this question asks about “slides”, the same would apply to letters, emails, etc.
PAAB Q&A 750 also walks through a similar set of questions to ask about the activity.
A letter stating only that the sponsor’s product is available would be exempt from preclearance regardless of the source within the company. But it should be noted that certain industry association Codes do not permit such promotional materials to be signed by Medical/Scientific personnel.
Similarly, a letter only indicating that the sponsor’s product is not available would also be exempt. However, in my experience, when such a letter is signed-off by medical/scientific personnel, it’s because the letter goes beyond that simple message (e.g., why the shortage exists, when the shortage is expected to be resolved, what is being done to mitigate the shortage, what prescribers can consider in the meantime, or so on). Anything on this matter beyond the fact that the product is available or unavailable would require preclearance.
If you are unsure if the activity would be considered advertising, and if that advertising requires review, please submit a request for a written opinion (see fee schedule on the PAAB website).