Combination therapy from the regulatory perspective

For a combination regimen to receive regulatory approval, it must provide some incremental advantage over a previous standard. Although this advantage is typically a greater likelihood of achieving a clinically relevant endpoint, there are others. For example, the additive effects of two agents may allow each to be employed in relatively low doses, improving tolerability. In age-related macular degeneration, one challenge to the combination of pharmaceutical agents is the delivery of adequate quantities of two or more pharmaceutical agents to the back of the eye. The confined space limits accommodation of substantial single dose volumes, whereas repeated invasive delivery through intravitreal injection may be impractical. Innovative delivery strategies may be crucial to future progress.