Is it possible to search PRs by the project's topic?

Is it possible to do this? My organisation has a number of projects so when trying to search PRs I only want to search repositories that are related to my project. Currently the way a repo is associated with a project is by the topic. For example the topic for is “govuk-pay”.

However this doesn’t work:

is:open is:pr label:dependencies topic:"govuk-pay"

As far as I know I can’t search by PRs by topic.

Any workarounds would be appreciated too.