CIC uses the 2016 classification. See belowNOC 1122 is present in the NOC 2016 classification. However, CIC uses NOC 2011 classification, which does not list Regulatory Affairs under 1122.
I worked as a Regulatory Associate and used the code 4165. I had the reference letters from both my companies with certain duties and responsibilities that matched 4165. I strongly suggest to check with your duties and responsibilities. Ultimately, the reference letter and NOC should fairly match.
Thanks.
https://www.canada.ca/en/immigration-refugees-citizenship/services/immigrate-canada/express-entry/become-candidate/eligibility/find-national-occupation-code.html