Check is list contains specific string

I have a two variables (PACKAGE_NAME and PACKAGE_LIST) and I am trying to check if PACKAGE_LIST contains PACKAGE_NAME.

Here is what I have:

PACKAGE_LIST="rpm-foo-bar:5.0.1"
PACKAGE_NAME="rpm-foo"

if [[ ${PACKAGE_LIST} =~ "${PACKAGE_NAME}" ]]; then
  echo "PACKAGE_NAME is in PACKAGE_LIST"
else
  echo "PACKAGE_NAME is NOT in PACKAGE_LIST"
fi

The problem I'm having is that while rpm-foo is similar to rpm-foo-bar, it is not the same and should fall into the else statement (PACKAGE_NAME is NOT in PACKAGE_LIST). I've tried adding a $ to the string comparison, however this only works if PACKAGE_LIST ends in the PACKAGE_NAME. Instead, PACKAGE_LIST has a version appended to it. How can I make make this check smarter so that the check falls into "PACKAGE_NAME is NOT in PACKAGE_LIST"?

NOTE: sometimes PACKAGE_LIST will not contain a version and will look like:

PACKAGE_LIST="rpm-foo-bar"