One of the main challenges of photodynamic therapy is that biological tissues absorb and scatter the light used in the therapy.[1] This seems to limit the effectiveness of such therapies to tissue depths less than 1-2cm.
The review article cites three studies as examples of in vivo photodynamic therapy; however, none of these overcome the challenge of tissue penetration. The first study [2] is a skin xenograft model (which needs very little tissue penetration and does not seem obviously superior to topical therapy), the second [3] pre-treats virus before inoculation (technically not an in vivo model of photodynamic therapy), and the third [4] was in oysters and used curcumin[5].
For what it’s worth, several of us at Alvea have been keeping a close eye on this for a while. If this escalates, then it is very likely that we would respond appropriately. (Note: My opinions are my own and I do not speak for Alvea in any official capacity.)