The following is my understanding, which could wrong!
The A2-73 patent has expired and had it been approved and marketed with commercial value, the drug could now be subject to generics. Alas, in all it's 20 years of patent protection it has not been approved for any indication and has made no money for the owners. So not much risk of generics at this time.
The molecule on it's own of course is no longer novel and thus no one, including Anavex, could ever again obtain that same patent protection.
Given novelty and utility, a combination of A2-73 with some other drug e.g. Donepizil could be patented as is the case with Anavex Plus. This does not extend the patent protection of A2-73 on its own. Only the combination drug enjoys protection.
Other alternatives include patenting new uses e.g. slow release or new indications, not previously disclosed in the original patent or elsewhere. This, not withstanding the marketing exclusivity that may be granted by the FDA for each new indication the drug may be approved for.
Finally, someone could in principle develop some other novel and useful combination of the A2-73 molecule with another drug not disclosed in the Anavex Plus patent. However, again as A2-73 has yet to be approved for any indication, it stands to reason that this is unlikely to happen, at least in the foreseeable future.
Once A2-73 might be approved in one or more indications, presumably the game could be on trying to come up with and patenting other combination drugs to include A2-73 for various indications. However, if the Anavex Plus patent is well crafted it could prove a difficult and expensive route for the competition to steal some Anavex revenue.
Now with this background of course Anavex could and likely will seek to obtain marketing approval for A2-73 on it's own and market it as such.
Not sure if the combination drug will need to go through any trials and approval, but presumably not as both drugs would already have approvals.
So altogether the combo patent puts blockers in the way of the competition even though A2-73 on it's own is not protected.
Does that make sense or am I just completely misguided?
