Population-specific safety occurs when the safety studies for a therapy are performed in a limited or specific population. This is not unusual since beyond initial phase 1 clinical trials, clinical trial participants usually have a specific disease or condition and are of a specific age range (e.g. adults vs pediatric).
For instance, a therapy that has been approved previously to treat a specific disease may only have data on the safety of that therapy in that specific disease population. Repurposing the therapy for a different disease may require new safety studies. New safety studies may be needed to gain approval for the therapy to be used in pediatric patients if the clinical trial participants were adults. Approval for use in pregnant women also requires new safety studies. Population-specific safety also highlights the need for safety studies to be performed in representative study populations.