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Legal and Constitutional Affairs Legislation Committee
31/03/2015

MATHER, Emeritus Professor Laurence Edward, Private Capacity

[10:02]

CHAIR: I now call Emeritus Professor Laurence Mather. Professor Mather, thanks very much for being with us today. We have a submission from you, which we have called No. 17. I am not sure if you were here earlier but I just need to mention that this is a parliamentary proceeding, and parliamentary privilege applies. If you want to say anything in camera, please raise that with us. If you want to make any additions or amendments to your written submission, you can do that now. Otherwise, or in addition, I will ask you to make a short opening statement, and then we will put some questions to you. Thank you for being with us. Over to you.

Prof. Mather : Thank you, Chairman. Good morning, committee. My name is Laurence Edward Mather. I hold the title of Emeritus Professor of Anaesthesia at the University of Sydney, and I appear as a private individual, officially long retired. I am a medical scientist with over four decades of research and teaching experience in the fields of applied chemistry, pharmacology, biopharmaceutics and therapeutics in Australia and overseas. During this time I have performed both laboratory and library research on many drugs, including cannabis. Based on my own research and that of the growing worldwide body of research, I have concluded that the legal, medicinal use of cannabis should be permitted, regulated and controlled.

Cannabis is an ancient herbaceous plant. Its botanical name derives from the Latin for 'hemp'. Various preparations from cannabis foliage and florets have been used for medicinal, dietary, fibre-making, religious, spiritual and recreational purposes for millennia. In drug parlance, cannabis is often referred to using the American terminology 'marijuana' to distinguish it from 'hemp', the name usually associated with the fibre. But such distinction is chemically moot. The preferred name is the botanical name: cannabis.

In Australia and many other places, due to its illegality, resources associated with cannabis have been directed in abundance towards law enforcement and societal dissuasion. Similarly, research of its harms from its non-medical use has been promoted whilst research of its medicinal use has been thwarted. Nevertheless, there is a sizeable literature pertaining to the medicinal use of cannabis and, in the course of my research, I have read many hundreds of such documents concerning pharmacotherapy using various cannabis preparations and derivatives.

The present peer-reviewed standards of evidence for such pharmacotherapy of a number of chronic conditions lead me, along with many other experts, to judge it to be a useful second-line treatment—that is, for use when first-line or conventional treatments fail to provide an acceptable outcome. However, this is a conservative viewpoint and is likely to undergo revision as more is learned of the human biology of naturally occurring cannabis-like substances or pharmacological developments of different chemical variants of cannabis and of biopharmaceutical developments of various dosage forms for cannabis. Thus there remains the strong possibility that selective preparations of cannabis could become first-line pharmacotherapy for certain conditions within the near future. Thus I maintain that the legal medicinal use of cannabis should once again be permitted.

Cannabis, like all other plants, contains many chemicals that demonstrate clinically relevant activity in laboratory pharmacological models as well as intact organisms, including humans. However, the concentrations of these chemicals may differ in different strains of the same plant species, with additional variations introduced by the conditions of plant growing, harvesting, storage and processing. Indeed, over 40 years ago I personally performed research demonstrating such chemical variabilities in samples of Australian grown cannabis, and others—you have heard from Professor McGregor's group—continue to confirm such findings. Thus I maintain that the legal medicinal use of cannabis should be regulated.

When used as a medicine, cannabis cannot be regarded as a single drug, and therein lies an issue. Conventional regulatory bodies have no framework for examination and approval of potentially variable mixes of drugs. Conventional pharmaceutical companies have little to gain from investing in natural products that cannot be patented or bear an illegal drug label. Nonetheless, individuals, many of whom are patients under medical supervision, use cannabis for medicinal purposes, despite its illegality. Its illegality derives from the fact that many other individuals use cannabis for non-medicinal purposes. Numerous highly useful legal but controlled drugs also may be used by individuals for illegal, non-medical purposes. However, frameworks for controlling the distribution and use of such drugs have been put in place. Thus I maintain that the legal medicinal use of cannabis should be controlled.

It is common for detractors to claim that there is not enough evidence or that the evidence is weak or that there are already sufficient drugs that cater for the pharmacotherapy afforded by cannabis. I maintain otherwise. Moreover, I venture to add that there are many drugs in current use, including some supported by the PBS listing, for which the evidence of therapeutic efficacy and safety is not as strong as that for cannabis, even allowing for inconsistencies in the cannabis products used.

I have no expertise in politics or the law and thus have no expertise for a line-by-line parsing of this or any other bill. Over many decades, people engaged in politics and the law have essentially decided that cannabis has no therapeutic value, despite the evidence provided by people with medicinal and scientific expertise that it does. I find this situation to be incongruous. The elements of this present bill are intended to create a nationwide framework for the regulation and control of cannabis and its preparations for medicinal purposes. If this framework allows cannabis medications to be legally available for research and study and ultimately for use at a cost affordable to Australian patients in every state and territory, either through PBS or non-PBS listing, whether by big pharmaceutical companies or otherwise, then this bill will serve many people in Australia who have no access to cannabis as a potentially legal medication or only have access to cannabis as unregulated, uncontrolled, illegal medication. I therefore support the introduction of this bill.

CHAIR: Thank you very much, Professor. That is very useful. We will go to Senator Singh for questions.

Senator SINGH: Thank you, Professor, for you submission. The committee is basing its inquiry on the bill before us, which deals with the medicinal use of cannabis. What do you see as being some of the hurdles that we may encounter if we are going to put in place this new regulatory framework? Obviously you see it as a benefit—a number of us do—and we have had a lot of evidence to say the same. I am trying to see what kind of hurdles we might come up against through creating this kind of regulatory approach.

Prof. Mather : I have perused the majority of submissions on the website and have seen that a lot more learned people than I in bills and things of the kind point to deficiencies in the bill or suggestions for improvements to the bill. I really cannot improve upon any of those comments because I have no specific knowledge.

Let me take you back to the issue that I see this bill really addresses. On 4 July last year there was a teleconference between Professor John Skerritt and Dr Tony Hobbs of the TGA and myself and Dr Alex Wodak, who will also appear before your committee. We were addressing the issue of how cannabis could be seen by the TGA, because it essentially is a crude product. The issue of this crude product presents difficulties because the existing models that the TGA operate do not really cope with this due to the variability of active ingredients. These are well-known stumbling blocks. Professor Skerritt responded that the model that he sought for cannabis might be closer to that which is used for complementary medicine such as St John's Wort and things of that kind that are believed to have medicinal uses, but where different manufacturers claim different advantages through their different processes or their formulation or whatever. You are all familiar with this—when you walk into the pharmacies and see all the complementary products on the shelf, there are many competing products. These products represent similar issues to cannabis. But Professor Skerritt pointed out that the model that the TGA operates—in their case, for dealing with such products—fails in the case of cannabis because the advertising of complementary medicines of this kind is not permitted to make claims for the medicinal use of that product. Whereas we are dealing with a product that is intended for medicinal use.

I do not know what submission you might see from the TGA, but I imagine that they would not welcome a body that really takes this kind of legislation or this kind of examination outside of their domain. Indeed, I saw such submissions on the website; I think Health and other people of that kind said they saw no need for setting up a parallel apparatus for handling such issues. In my limited experience and based on this conversation we had with the TGA about how cannabis could be treated, I believe this will solve that issue; it will set up a process by which this can be done. Additionally, as you are well aware, state by state and territory by territory, other governments are trying to cope with this issue as well. We are likely to see yet another dog's breakfast of all kinds of legislation on what is permitted and what is not permitted, and so patients and researchers and others will fall foul, I believe, of this inconsistency of regulations.

Many years ago now, in about 2003, not long after I was involved in the New South Wales Premiers' committee on medicinal cannabis, I submitted some research grants. One was to the NHMRC and one was to a state health body for studying cannabis in use with patients with neurological injuries. It seemed a very logical thing to do, and I put together a consortium of researchers from various universities et cetera, to apply their particular part of the expertise to the part of the problem that was needed. With this multi-disciplinary approach we succeeded in putting together a very, very good proposal. But it was a proposal that was all done within the state so that we did not violate any of the state's rules by bringing cannabis from one state to another and things of that kind. I believe this is where your bill has its strength—to provide a mechanism for nationwide uniformity.

CHAIR: The TGA gave evidence yesterday in Canberra. You might be interested in having a look at their evidence on the Hansard when it is up, in a couple of days. They were fairly neutral about it all, which was interesting.

Prof. Mather : Which is pleasing.

Senator URQUHART: Thanks very much, Professor Mather. In your submission you said that you have extensive experience advising state and territory governments in relation to issues about medicinal cannabis for well over a decade. Why has it taken so long? What are the barriers? How far have you moved in that time frame and what sort of advice have you been giving to state governments?

Prof. Mather : My role really has been to present the medicinal scientific evidence for the usefulness of cannabis. I have not been able to provide any advice at all about how to go about it. I have been convincing, I believe, many people who make laws that cannabis has medicinal properties which are salutary. It certainly has side effects which are known, but indeed they are not so severe or so frequent as to be able to say cannabis should be not used because of this. So I have been trying to carry out really more of an educational role, I would say. If I have been able to permeate education then I have been doing my role. I really cannot go beyond that, I do not think.

Senator URQUHART: Do you think you have been able to achieve that education?

Prof. Mather : I saw that the New South Wales Legislative Council inquiry, for example, came out with a multiparty unanimous position that they believe cannabis has medicinal use that is useful to patients. So if I have been able to have input of that kind then I believe I have done my thing.

Senator URQUHART: Okay. Have you been involved in part of that education across all state and territory governments?

Prof. Mather : I have made submissions to Tasmania, the Australian Capital Territory and I believe others of that kind, yes.

Senator URQUHART: Okay. I might leave it there given then time and let others have a go.

Senator DI NATALE: Let's go quickly to the evidence because that is an area where you have considerable expertise. You say in your submission that it is common for critics to claim there is not enough evidence or that evidence is weak and then you go on to say that the hardbacked, peer reviewed, published evidence supports the use of cannabis as at the very least a second-line treatment for a number of conditions. Can you expand on that a little further so that we are clear about the evidence for its effectiveness as a second-line treatment?

Prof. Mather : I will put it this way. My memory is not as good these days; I normally use aides-memoires, which I will skip at the moment. The most convincing evidence really comes from serious reviews of the papers and the research. If one looks at the amount of evidence that has been produced despite the difficulty of the publication bias and all the things we know about that occur with medicinal uses of cannabis, the broad trends of the evidence—one particular study, for example, suggested there were 82 trials reporting beneficial effects of cannabis and nine trials that found no particular benefits or negative effects of cannabis. In terms of percentage or proportionality, that to me is pretty convincing that cannabis has beneficial effects.

That is in the peer reviewed literature and apart from the anecdotal literature. Anecdote and personal observation, of course, is permissible evidence in court but is not permissible evidence to editors of hardbacked journals or scientific bodies. Nonetheless, when you put all this together, the evidence is stacking up indeed that cannabis has medicinal use, and this is despite the fact that cannabis is being not defined as any particular product and looking right across the range of all the possibilities of cannabis. So, if cannabis products were selectively prepared for individual patient groups, one could envisage the outcomes would be much more favourable than simply looking at it on the broad title of cannabis or cannabinoids.

The evidence that I believe is out there seems to be denied or dismissed either naively or intentionally by many people simply because they want to prevaricate on the evidence or really have other motives in denying the evidence or the strength of the evidence.

Senator DI NATALE: Let's go to the medical community. I think there are different views within the medical community. It is fair to say that there are some medical groups that are more cautious. We may hear from some of them later on today. I have my own views about why some of them are resistant, but what do you think in your own view? Is it just a question of ignorance of the evidence or is there something more to it?

Prof. Mather : It could be ignorance. It could be laziness or lack of time. There are all sorts of possibilities why a particular body may not want to go into the evidence. There is also the typical medical caution, the 'do no harm' dictum that is important. But the issues have really not been objectively weighed, because I suspect many of these bodies have never really been called on to weigh up the evidence and look at the individual trials and sit down with the original papers for themselves to evaluate them and read them in detail as I have done over the years.

Senator DI NATALE: That is my own experience in medical practice. I had very little knowledge in the area except very fleeting bits and pieces I picked up in a journal here or there. It is not something that many of us in practice have a great deal of experience with. Is part of the issue—and you say this in your submission—that it is not a single molecule, that it is a combination of molecules? We have heard that ratios are important and so on. Is that part of the issue?

Prof. Mather : Let's put it this way: that is a way of being able to dismiss the evidence should you wish to. 'We know that aspirin is aspirin and paracetamol is paracetamol, but cannabis is a mixture of many hundreds of substances'—that is a convenient way of dismissing the issue, yes.

Senator DI NATALE: So that is part of the issue. Perhaps we can put forward some of the evidence from one of the medical groups that is presenting later on today. There are few issues. One is this issue of replicating the function of an existing regulator. But I feel like we have addressed that because there are other functions outside of what the TGA does. But they talk about the issue that there is not a sufficient protection for medical practitioners from liability or to guarantee the efficacy and safety of medicinal cannabis products.

Prof. Mather : But surely that applies to so many other substances that medical practitioners prescribe every day? I guess it requires the legalities being set in place so that medical practitioners are protected, as they are when prescribing codeine, morphine or anything else. But the conservatism on the behalf of the medical fraternity is in a sense because they really do not understand the issues of cannabis. Cannabis is not a fail-safe substance but compared to morphine and things of that kind it is relatively fail-safe in the sense that it has side effects but they are not fatal. Morphine can kill people. Aspirin can kill people. Paracetamol can kill people. More people are hospitalised from paracetamol use than cannabis use. So the issue is the strain of conservatism running right through this. No doubt the quotation you just read relates to that kind of conservatism as well.

Senator DI NATALE: Finally, are you aware of any literature that demonstrates changes in opiate overdoses when cannabis has been introduced in other jurisdictions?

Prof. Mather : I am, indeed. It is interesting. There have been several papers in the last two years about this. One paper suggested that in patients prescribed chronic doses of opioids for persistent conditions such as chronic pain there was in the order of 25 per cent fewer opioid related deaths in jurisdictions where cannabis was available. I think another paper reported 10 per cent. Nonetheless, whether it is 10 per cent, 25 per cent or some other percentage, cannabis is a relatively fail-safe medicine. The nonsteroidals that might be used in those patients can cause kidney damage and liver damage. The opioids that might be used can stop breathing and cause death that way. Cannabis is not known to cause fatalities.

Senator DI NATALE: Just to be clear about that, when medicinal cannabis was introduced in those jurisdictions, we saw fewer people dying from overdoses of opiate medication because they were stopping their opiate medication and going on to medicinal cannabis?

Prof. Mather : Either stopping or reducing their opioid medication, yes. I do not recall what the actual wording was in the papers. There were several papers. This is based on evidence from those states in the United States that have their so-called medical marijuana laws.

Senator DI NATALE: Thanks for that.

CHAIR: Professor, I guess the restrictions and complications these days come from a time some decades ago where the authorities were concerned about the harmful effects—particularly from THC—of cannabis. Do you think that the bill we are looking at ensures that there is no unregulated use of particularly the THC element of cannabis in the wider public?

Prof. Mather : I am not sure how to interpret your question.

CHAIR: Well, that was the original concern, years ago. One of the problems that people like you and other medical researchers are experiencing now is because there was a caution about anything that allowed cannabis to be legally obtained for any reason. From your understanding of the bill—and I appreciate you are a medico, a scientist, rather than a lawyer—are you happy that the bill does not make cannabis more readily available to the wider public for recreational use?

Prof. Mather : I saw no evidence of that in my reading of the bill.

CHAIR: Thanks very much, not just for your evidence here in person but also for your written submission. We very much appreciate your assistance, and thanks very much.

Prof. Mather : It was a pleasure.