14 December 2016 Last updated at 15:53 GMT
She told BBC Scotland: "Not every drug will be approved and no system will approve every single drug.
"What this will do will make, particularly those really ultra-orphan drugs that are for very rare conditions, will make it fairer and have more equitable access to those drugs."
Scotland's Health Secretary Shona Robison said changes to the way drugs for rare health conditions are approved will be fairer in the future.