Is there a high chance of US and UK courts grappling with medicinal cannabis patents?

The US and UK patent offices have granted a number of patents relating to the therapeutic use of cannabis derived products. Paradoxically, both the US and UK governments currently define cannabis and cannabis-derived products as having no medicinal benefit. Recent developments suggest that both governments may soon soften the legal definition of cannabis. This Kat takes the opportunity to ask, in view of the US and UK governments current position that cannabis has no medicinal use, how strong are the patents claiming the very same?

The legality of cannabis derived products is complicated by the broad spectrum of potential substances to which this term may refer. The cannabis plant contains at least 85 cannabinoids. The most prominent of these, cannabidiol (CBD), is non-psychoactive and has been associated with a number therapeutic effects. THC is the second most prevalent cannabidiol in cannabis, and is the primary psychoactive substance. Cannabis derived products contain varying amounts of CBD and THC.

Legal status of cannabis

Recreational cannabis is subject to varying restrictions around the world. In the UK, the Misuse of Drugs Act 1971 categories cannabis and cannabinol as Class B drugs, meaning that unlicensed supply carries a maximum penalty of 5 years in prison and/or an unlimited fine. Cannabis has been fully legalized in certain US states (e.g. Colorado), and it will soon become fully legal to grow, possess and sell Cannabis in Canada.

The legality of medicinal cannabis is distinct from that of recreational cannabis. The legislation governing whether licences can be awarded to supply a controlled substance for medical purposes is dependent on whether that substance is considered to have a proven medicinal effect. Cannabis was categorized by the UN Convention on Narcotic Drugs as a drug having "no medicinal benefit" (Schedule 1). Both the US and UK currently follow this classification.

Nevertheless, both the UK and US have approved the use of particular forms of cannabis for medicinal use. In 2010, the UK government granted GW Pharma a licence to manufacture Sativex (containing CBD and THC) to treat the symptoms of multiple sclerosis. The UK also moved Sativex from Schedule 1 to Schedule 4, such that it can be legally prescribed (although it is considered too expensive for the NHS).

Cannabis oil containing less than 0.2% THC is also legal in the UK, but cannot be supplied for medical purposes without a licence. Suppliers of CBD oil market it as a "health supplement".

In the US, the FDA very recently approved another GW Pharma product, Epidiolex, for the treatment of seizures associated with rare forms of severe epilepsy. Epidiolex is an oral solution of pure CBD . The expectation is that the FDA will now also reschedule Epidiolex as a non-Schedule 1 drug. The European Marketing Authorization (EMA) is also currently reviewing a Marketing Authorization Application (MAA) for Epidiolex, the result of which is expected in early 2019. If the EMA approves Epidiolex, it will be possible to prescribe it throughout the EU. GW Pharma recently announced that Epidiolex is expected to cost ~$32,500 per year (on the low end of many predictions).

In the meantime, there have recently been a number of high profile cases in the UK concerning child epilepsy sufferers who were denied potentially life-saving treatment in the form of cannabis oil containing THC. In response, the UK's Advisory Council on the Misuse of Drug (ACMD) recently advised the Home Office that cannabis products other than Sativex should be considered to have medicinal benefit. The ACMD further advised that cannabis and canabanoids should not be placed in Schedule 1. The government has announced their intention to follow these recommendations, and particularly that they intent to reschedule some cannabis products as Schedule 2.

The legal situation relating to medicinal cannabis is thus complex and in flux. Both the US and UK governments appear to be moving towards a growing acceptance that some forms of cannabis have a medicinal use. So how does all of this interact with the patent protection available for medicinal forms of cannabis?

Patenting cannabis

In the UK and Europe, an invention cannot be patented if its commercial exploitation would be contrary to public policy or morality (UKPA Section 1(3) and EPC Article 53(a)). This exclusion does not prevent patenting of inventions merely because their commercial exploitation would be illegal (Section 1(4)EPC Article 53(a)). Therefore, it is in principle possible to patent inventions relating to cannabis, even before a change to the law allowing prescription of medicinal cannabis.

CBD oil for Kats
However, before a drug for use as a particular treatment can be patented, it is necessary to demonstrate the claimed therapeutic effect is plausible. The current scheduling by the UK government of cannabis as a Schedule 1 drug, i.e. having no medicinal benefit, might therefore indicate that the Patent Office would be unwilling to grant a patent relating to cannabis for a medicinal use.

However, this has not been the case. GW Pharma in particular have a number of granted UK patents relating to cannabis for medicinal use. These include: GB2554592, claiming THC and CBD for use in the treatment of a glioma; GB2504263, claiming CBD for preventing brain injury in newborns and GB2495841, claiming CBD for the treatment of breast cancer. GW Pharma also have granted US and European (UK) patents relating to Epidiolex (e.g. EP3157512).

The USPTO also has an established practice of granting patent relating to the medicinal use of cannabis, again in apparent contradiction to the position of the US government on the alleged medical uses of cannabis. In 2016, the Drug Enforcement Administration (DEA) rejected a petition to reschedule cannabis as having medicinal use. This appeared hypocritical to some, in view of granted US patent US 6,630,507co-owned by a US health insurance company and the US government (NIH) itself, claiming:
 "a method of treating diseases caused by oxidative stress, comprising administering a therapeutically effective amount of a cannabinoid that has substantially no binding to the NMDA receptor ...".
In response to criticism leveled at the NIH regarding this patent, Mark Rohrbaugh a Special Adviser for Technology Transfer at NIH was reported as saying that the patent does not yet prove the chemical compound is effective in the stated treatment. The requirements to demonstrate a claimed therapeutic effect are less stringent in the US than in Europe. However, the European(UK) case has also been granted with equivalent claims.

Enforcement and validty?

The restrictions on the sale of cannabis for commercial purposes have meant that enforcement of patents relating to the medicinal use of cannabis has, so far, been largely unnecessary. However, hot on the heels of the FDA approval of Epidiolex, the first infringement action relating to sale of a medicinal cannabis product was filed in the US (see here). The patent (US 9730911), in the name of Colorado based US Cannabis Corp., claims a cannabis extract containing 95% total cannabinoids, wherein at least 95% of the total cannabinoids may be cannabidiol (CBD).

However, it has been posited that patents such as US 9730911 are weak and will therefore be difficult to enforce. This has been blamed on the sparsity of prior art in the field available to the patent office that can be cited against an application. Another issue may be that whilst research papers and patents may be relatively few in number, common general knowledge of the medicinal effects of cannabis goes back centuries.

Additionally, will the US Government's own definition of cannabis as lacking medicinal benefit affect the validity of a patent relating to the same? The recent indications of a shift in position of the US and UK governments in line with published scientific evidence may ameliorate this risk, although government statements at the priority date of an application are unlikely to be helpful.

In view of all this, how strong are the granted patents relating to cannabis for the medicinal use? Will we see a difference in the European and US approach? Regardless, should the validity of these patents be considered by the courts, they will undoubtedly be interesting test cases on the extent to which the technical effect of an invention must be demonstrated in the application as filed.
Is there a high chance of US and UK courts grappling with medicinal cannabis patents? Is there a high chance of US and UK courts grappling with medicinal cannabis patents?  Reviewed by Rose Hughes on Wednesday, August 22, 2018 Rating: 5


  1. "The current scheduling by the UK government of cannabis as a Schedule 1 drug, i.e. having no medicinal benefit,..."

    That is not evidence that there is no therapeutic effect. It is a rather naïve proposition to be making to suggest or question the validity of a patent on this basis. Why not challenge one of the patents in any of the appropriate forums with this 'evidence' and see how far you get?

    I suggest obtaining some advice on this assertion first: "However, before a drug for use as a particular treatment can be patented, it is necessary to demonstrate the claimed therapeutic effect"

    As for the statement: "This exclusion does not prevent patenting of inventions merely because their commercial exploitation would be illegal" - no commercial exploitation of a medicinal product can be made without a valid marketing authorisation to do so, so any product made commercially available would be legal and not contrary to public policy.

  2. The UK Patent Office has been granting patents for inventions that are illegal to put into practice in the UK for years. An example that used to be given in the Manual Of Patent Practice was CB radios, which used to be illegal to use in the UK at the time the Manual was drafted, but which could be manufactured in the UK for export.

  3. In reference to the US, this subject has been extensively examined. McNichol, William, The New Highwayman: Enforcement of U.S. Patents on Cannabis Products (February 20, 2019). 101 J. Pat. & Trademark Off. Soc'y 24 (2019). Available at SSRN:

  4. This comment has been removed by a blog administrator.


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