A Q&A With David Meiri

For many familiar with medical cannabis research, David Meiri needs no introduction. For the last four years, he’s managed one of the largest cannabis laboratories in the world at the Technion Israel Institute of Technology – a lab that’s revealed some of the most startling findings about medical cannabis’ properties, and one that might be on the cusp of a cannabis-chemotherapy breakthrough. After speaking at the CannMed 2019 conference in Pasadena, California, Analytical Cannabis caught up with Dr Meiri to talk cannabis, cancer, and clinical trials.

Leo Bear-McGuinness (LBM): How have you found CannMed 2019?

David Meiri (DM): You see how the field stabilises a little bit. Three years ago, you saw a lot of patients and the older generations you treat, and then this conference changes to be much more accurate and more professional. So I think it's healthy for the industry. It's good to see how this industry is stepping forward to be more accurate, more precise, more real. These people that were advocates for cannabis succeeded to bring it to a certain level, and I'm admiring them. Now it's moving to the next level, which is extremely important. We want to really [be] treating patients and take it to a place that is admired by governments.

LBM: You referred to the endocannabinoid system as the “endocannabinoid-biome” in your presentation. Is this a phrase that should be used instead?

DM: People usually talk about CB1, CB2, 2AG (2-arachidonoylglycerol) and other openers. But there are huge amounts of enzymes, ligands, receptors [involved in the endocannabinoid system]. We have terminology in science for that. If there were three bacteria in our gut we would name them, but it's a microbiome. It's like a population. So I think we need to use terminology also for the "endocannabidome." Because I'm looking on 150 ligands on 28 receptors; it's a wide range, so I need to give it terminology that covers everything.

LBM: Your presentation highlighted that many studies into cannabis’ effect on pain have been self-reported. Does that mean that medical marijuana’s raison d'etre – pain management – is up for debate?

DM: No, but if you look in very specific and narrow window on pain, you would say it's not good. If you look how I think you should look on cannabis policy – more holistic and doing other things that are related to pain and depression, sleep, anxiety – now you're treating all of them and the patient is much, much better. If you look just to measure a very, very narrow question, then you will fail. You really need to look on that in the wide range, which is the bottom line: is the patient better or not? Then you will realize – and I showed this in the last figure – that the patient is much better.

LBM: But, just to be devil's advocate, could you not say the same thing for going out for a country walk or a hike?

DM: I probably would agree with you, yeah. But walking will increase your endorphins and your endocannabinoids. So it's on the same pattern – improving your sleep, improving your appetite, improving your mood, it's the same thing, if you ask me. I prefer to swim or to hike than taking cannabis. But that's the reality: people take drugs a lot of the time, which can solve [medical issues] and I'm not against it.

LBM: Of course, one has to make a lot more policy and regulatory changes to take cannabis than to go for a walk.

DM: I agree, it seems like a lot of efforts. [This] question is extremely important. To me a lot of patient cases can be solved with other ways. If you are suffering from back pain, it might be that if you strengthen your body muscles, this pain will be lower and you can live with it.

LBM: You’re starting a new cannabis-cancer study soon. Yet, cannabis’ anti-tumor properties still aren’t well understood. Do you have any idea how cannabis could be, in effect, killing cells?

DM: I agree that it is confusing. But when you have defect in [a] pathway, which sometimes happens in cancer, the cannabis can change things that will lead the cells to die, which normal cells just won’t do. This is what we are looking for. Not in all types of cancer cannabis is killing the cells, and there are high strength killing cells that can be harmful.

The dosing is [also] very, very important. You want to find the ratio that will kill the cancer, but not the normal cells. It's a matter of ratio and the amounts, and what caused the cancer, and why it's different from the normal.

LBM: Israel's regulatory system is much more relaxed than the systems of other countries when it comes to medical cannabis research. Do you see more human cannabis-cancer trials progressing in five years?

DM: In Israel, it's quite easy to do clinical trials in cannabis for extracts. There are a few clinical trials in Israel running regarding cancer. So we have a few clinical trials running around cancer patients taking chemotherapy and how it's affecting them. There is neuropathic pain caused by chemotherapy, there is how cannabis affects the immunotherapy, and there is also [a] few clinical trials to treat the cancer. There is one on glioblastoma. There is one with the Rick Simpson oil. There is one that I'm about to start in the leukaemia. So when we find something, we believe it's not difficult to start.

I follow up on a lot of patients taking Rick Simpson oil. Now, I was a big believer, but unfortunately I didn't see good results. Almost none of them showed improvement. There was [sic] quite severe side effects that people don't talk about, like bleeding from the intestine and then they're vomiting, and suffering from other side effects. They become very weak. Around 1 in 200 I saw improve – that’s [sic] half percent. So now the question is whether it's because these patients started to take Rick Simpson oil after they are [sic] in a very bad shape, like [as a] last resort, or whether it's because they're not fitting right – which cannabis to which cancer is just not working.

LBM: Could any cannabis-cancer drug be more effective than the chemotherapy drugs we already have?

DM: So, the cancer that I'm working on, the efficacy is higher than cisplatin (a conventional chemotherapy drug). This is actually what dragged me into this field. I worked on a colon cancer and I used cannabis and the efficacy was higher than Taxol (another conventional chemotherapy drug) in that specific way, and I thought, ‘this is crazy.’ It shocked me. So if you find the right cannabis with the right compounds with the right cancer and be realistic – there will be few types of cancer that will be treated by specific cannabis. It's not that we will solve the cancer problem in the world, but in this one [compound], efficacy is very high.

So we have very good results and [are in] a very good place. Now if you asked me two years ago, I would be much more hesitating [sic] and said, ‘I'm scientist, I’m doing my best effort.’ But we're already in the stage that I'm a big believer that there will be something. It's now just moving into clinical trials so we're not far from having something that is close to medicine for curing specific cancer – but very specific, I don't want to fool anyone. But in leukaemia I will be very, very surprised if I didn't succeed in clinical trials.

David Meiri was speaking to Leo Bear-McGuinness, science writer for Analytical Cannabis, at CannMed 2019.