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Getting the science right on medicinal cannabis

Aug 3 2015

Premier Mike Baird

By Professor Jennifer Martin* Life for terminally-ill cancer patients is often made more distressing by symptoms such as fatigue, nausea, suppressed appetite and weight loss. In desperation, some turn to the streets for the first time in their lives to buy and try cannabis.

If the patient confides after taking the drug, as doctors we advise that it’s illegal and can’t be condoned, even if people say they are getting benefit.

There may be interactions between cannabis and other drugs we aren’t aware of. More so, it presents a moral and ethical quandary for those sworn to deliver the best possible care and quality of life. It feels like we aren’t listening to patients because we can’t advise them.

All we can do is administer a suite of approved drugs, like steroids in the case of appetite stimulation, which are perhaps not optimal in countering the symptoms and often have problems of their own.

On July 27, NSW Premier Mike Baird and Minister for Medical Research Pru Goward announced Australia’s first medical cannabis trial for terminally ill adults, to be led by Associate Professor Meera Agar from South Western Sydney Local Health District and the University of NSW.

In outlining the $9 million commitment, Premier Baird stated: “We do not want patients or carers having to play pharmacist – that is why it is so important to explore the safest and most effective ways we can deliver compassionate care and improve the quality of life”.

The initial stage will enrol approximately 30 patients in a clinical pharmacology study conducted by the Discipline of Clinical Pharmacology at University of Newcastle/HMRI, based at the Calvary Mater Newcastle, with the Hunter as the recruitment hub.

We have other clinical research underway in Newcastle delving into the use of pharmacology tools to individualise the dose of drugs in other diseases. We are also studying the components and effects of synthetic cannabinoids and other drugs of abuse.

The track record of Newcastle as a centre of excellence in clinical pharmacology was the catalyst for Associate Professor Agar to approach our team. Our objective is to find what cannabis dosage is right for a potentially frail, underweight, end-of-life cancer population.

It is not for pain management but primarily a means of combating ‘cachexia’, the wasting syndrome that stops cancer patients from wanting to eat.

No stone has been left unturned in the design of the trial – the way we selected the drug and the method we’re using to administer it. Two mathematicians have worked for six months just to determine the starting dosages.

Our concern is that some patients will experience adverse reactions to cannabis – such as psychosis, in which they feel paranoid or delusional. We don’t want patients getting unwell from toxicity and other side effects.

This will be the first study of its kind with a matched placebo arm, where we can determine if the thought of receiving cannabis triggers a response or whether it’s the tetrahydrocannabinol (THC) component. Our bodies make cannabinoids naturally, which is why measuring the placebo effect is so important in this study.

As scientists we’re starting with what’s called a null hypothesis, where the assumption is that cannabis will be no more effective than a placebo. If there is a positive effect our pharmacology study has been designed to see it; if it’s negative we know that incorrect dosage is not a factor.

Our major challenge is to give exactly the same type of drug each time to each person. The recreational product varies between growing location and even within batches, and no commercial crop in Australia is sufficiently consistent. Therefore we imported a pharmaceutical-grade supply with support from the State and Federal governments.

Patients of different age and weight ranges will be chosen according to their Karnofsky score, a measure of one’s ability to perform daily activities. Most will have a life expectancy of about three-six months.

The drug will be delivered through an apparatus that heats the botanical leaf and releases vapour into an inhalation chamber. After inhaling, participants will be shown a standard food chart to determine how much they feel like eating and asked about their anxiety and quality of life.

Ultimately, we will have more evidence available prior to starting the next stage, a state-wide trial of 300 patients.

The study may polarise opinions. Call cannabis what you will – marijuana, dope, pot, grass, weed – but please don’t confuse this medical-grade pharmaceutical with the street product.

Personally, I’m excited to think that this relatively old drug has the potential to benefit more people at the end of life than anything else I’ve done in my career as a pharmacology researcher and clinician.

* Professor Jennifer Martin is Chair of Clinical Pharmacology at the University of Newcastle and a practicing general physician at Calvary Mater Newcastle. She researches in conjunction with the HMRI Cancer Research Program and Hunter Cancer Research Alliance.