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Drug Development

Deuterated Drugs: The PTO Says OK, So Far

As a follow-up to the deuterated-drugs idea, I note (courtesy of a co-worker) that Concert Pharmaceuticals has press-released their first issued patents on deuterated analogs of existing drugs.
So apparently the novelty and utility requirements have passed the first major sniff tests. I don’t know if the case to be made for these (rimonabant and mosapride) is different than the others that Concert has on their IP assembly line, but I doubt it. If these issued, you’d figure that the others probably will, too. I can’t imagine that the rimonabant patent’s going to be worth all that much, though, since that drug has failed for reasons that I can’t see being addressed by a deuterium analog.
As mentioned here before, though, the IP space here seems to be rather crowded, at least when you look at the number of applications. It’s presumably quite a traffic jam at the patent offices – and it’ll presumably be some time before that gets sorted out. And that’s just at this stage of the game: if any of the companies in this space start to hit it big, it wouldn’t surprise me to see lawsuits, requests for re-examination and the like.

14 comments on “Deuterated Drugs: The PTO Says OK, So Far”

  1. Muruga says:

    It looks like that Auspex has also received a patent for SD-254, the deuterated analogue of venlafaxine.
    Rimonabant is metabolized by CYP3A4 (and also amidohydrolases). The potent inhibitors of CYP3A4 are known to elevate the exposure of rimonabant upto 2.7 fold. I am not sure whether the deuterium version of rimonabant was designed to mitigate CYP3A4 metabolism.

  2. Gunslinger says:

    Any change in molecular structure which produces a non-obvious change in the underlying utility (let’s say binding affinity), will likely be patentable if it’s novel. You can’t expect a patent on propecia with a deuterated site if it produces the same bio-activity. It’s the surprising change which must be proved to the patent office.
    Still, these are new molecular entities, so the patents might be offensive in nature, with little actual desire to receive the final patent. But by filing they produce new prior art which prevents patents on the compounds themselves.

  3. SRC says:

    I just checked. Those suckers sailed right through the PTO. The ‘131 patent was pending less than a year, and allowed on the first Office Action, so no need to overcome an obviousness rejection.

  4. weirdo says:

    So, like, what’s the business model here? License back to the innovator company, like Sepracor? I can’t see anyone else doing a deal with these guys . . .

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  6. petros says:

    It’s interesting to note that these patents ahve been allowed but was this the easy option for the examiners
    Most (all) of these deuterated compound applications stem from 3 companies
    Auspex, Concert and Protia.
    Protia’s patents appear to b a blunderbuss approach, with a mass of US filings 237 published to date but only 11 PCT applications.
    These all appera to provide no exemplification nor any biological description
    Concert has 39 PCTs and 26 US applications published
    Auspex 57 PCTS and 39 US applications.
    Both provide some chemical exemplification with some biological assays described. Of those I’ve seen only Asupex provides some data on improved metabolic stability.
    I’ve yet to come across one that shows any indication of pharmacological activity which, with the exception of certain enzyme inhibitors, would be expected to be the same as the original drug

  7. Anonymous says:

    The more interesting point for me is whether use of the deuterated compounds infriges a previous patent for the drug… Does the element ‘H’ in a structure cover deuterium? Surely there is an inherent lack of novelty in that at least some of the drug produced previously would be deuterated at naturally occuring levels… Any thoughts?

  8. Tok says:

    Anon #7 – You bring up an interesting point. If someone is granted a patent for a deuterated compound, if someone else is making it with naturally occurring isotopes, is that infringement? Would all other producers now need to use strictly undeuterated starting materials with all the naturally occurring deuterium removed?

  9. weirdo says:

    The rights granted to a later patent-holder do not surplant those granted to an originator. That was the point of my question above.
    If the innovator patent claims “and isotopes”, but one of these biotechs gets a patent to a specific isotopically-labelled version due to a “surprising” effect, that doesn’t mean the biotech can sell that version. They would still be infringing the earlier patent (I’m not an attorney and this is not legal advice yada yada yada . . . but I did stay at a Holiday Inn Express last night).
    And, Tok, I’m assuming naturally occurring D is OK, since there was a ruling a few years ago that human metabolites were covered when claiming a drug dosed to a human . . .

  10. Anonymous says:

    #9 Weirdo
    I agree with you on this one. I am a trainee patent attorney, so please don’t take me too seriously (lol). But even if a later patent was aquired for the all-D version of a drug (e.g. in a particular position on the molecule; assuming they could demonstrate unexpected benefits etc etc) then I would still err towards thinking that they infringe the earlier patent to the standard, non-D enriched drug (and so have to licence etc).
    This is the same as supposing that a patent can be granted for a single enantiomer, but that you still need to licence the patent for the racemate… (or is it?).
    It all depends on how the courts will interpret the scope of the earlier patent, and the courts can be funny things.
    If the holders of a patent to the all-D drug do need to licence the original patent, then they’d better hope that the new version is pretty good, and so tempts the earlier patent holders into some kind of agreement. Being pretty good (in an unexpected way) would also be a requirement of getting the patent in the first place though… so I can see how the strategy comes about.
    I’d love to hear any other opinions on this. Maybe a further post on this subject Derek?
    #7 Anon

  11. SRC says:

    Couple points. It’s perfectly possible to patent something that would infringe if practiced. In fact, this is very common. If someone claims a genus with R = A-Z, and someone finds that group G yields an especially useful compound, he can patent that specific compound over the genus. He can’t practice his invention, but he can patent it. The original inventor can’t practice the invention with R=G, either. This is similar to improvement patents in mechanical and electrical engineering, and both are classic cross-licensing situations.
    Second point, to #7, is that the applications I’ve seen specify unnatural isotopic occurrence (e.g., at least X deuterium atoms). That distinguishes them from the originally claimed compounds, and thereby provides novelty. The obviousness argument remains, however.

  12. Anonymous B says:

    Racemate vs. pure enantiomer was proven as a viable patent without business repercussion in the case of Sepracor i.e. Claritin vs. Clarinex which Schering Plough markets but Sepracor collects royalties on Clarinex as it is the pure enantiomer of racemic Claritin. The issue of naturally deuterated vs. fully deuterated would probably come back to the % of one vs. the other. If naturally deuterated is 10% and fully is average 90%, then the innovator wouldn’t be considered the same.

  13. weirdo says:

    OK, Anon B, you really need to brush up on some things.
    1 — Clarinex is not “the pure enantiomer of racemic Claritin”. It’s a metabolite.
    2 — Sepracor licensed their patent to Schering, the owner of the Claritin patent.
    3 — That patent was later thrown out, anyway.
    Color me skeptical.

  14. Anonymous in NC says:

    Given that Concert is co-opting a patented BMS drug, a lawsuit seems imminent. It is almost BMS’ fiduciary duty to challenge this.
    On a separate note, how is this really meeting an unmet medical need? In current environment it is going to just look greedy to all examining healthcare costs.

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