Currently Approved Cannabis-based Pharmaceuticals and Some in the Pipeline

Because of historical negative perceptions and ongoing legal concerns, only a few cannabis-based pharmaceuticals are currently licensed for clinical use. In the United States and Europe the synthetic Δ-9-THC drugs nabilone (Cesmet®) and dronabinol (Marinol®) and dronabinol (Marinol®) are approved for treatment and prevention of chemotherapy-induced nausea and vomiting (CINV; 1).  Another synthetic Δ-9-THC product, Syndros (dronabinol oral solution) received approval in 2016 for the treatment of anorexia associated with weight loss in patients with AIDS and for cancer patients with CINV who failed to adequately respond to conventional antiemetic treatments.

GW Pharmaceuticals’ Sativex®, an extract containing THC and CBD, is approved in 27 countries Europe and elsewhere for the treatment of spasticity associated with multiple sclerosis and, in Canada, is also approved as an adjunctive treatment for cancer pain (1) The CB1 cannabis receptor agonist rimonabant (Acomplia®) was approved for use in Europe to treat obesity but was discontinued because of serious adverse effects (2)

While the approved cannabis-based pharmaceutical list is quite short, there are several compounds and extracts that are currently being evaluated in human clinical trials for regulatory approval. Sativex®, which received FDA fast track designation, has completed Phase 3 clinical testing and an application for approval has been filed at FDA. Another GW Pharmaceuticals product called Epidiolex® received FDA orphan drug status and is currently in mid to late stage clinical testing as a treatment for orphan pediatric epilepsy including Dravet Syndrome and Lennox Gastaut syndrome

Other companies, including Arena Pharmaceuticals, are attempting to develop cannabis-based drugs and mimetics that treat pain by binding to certain types of cannabis receptors found throughout the body (3). Removing cannabis’ psychotropic effects and preserving its pain-relieving benefits is the major objective for this new class of pharmaceuticals.  Although these drugs are still in early stages of development, using them rather than addictive opioids to manage chronic pain would be an important step in combating the US opioid epidemic.

Although the future of cannabis-based pharmaceuticals in the US  is brighter than it has been over the past 50 years, there are still some major hurdles and obstacles that must be overcome. To gain some insight into some of these, please read 2015 testimony to Congress given by Douglas C. Throckmorton, M.D. Deputy Director for Regulatory Programs Center for Drug Evaluation and Research Food and Drug Administration.

Moreover, the approval process for cannabis-based pharmaceuticals has an additional layer of complexity as compared with conventional pharmaceuticals.  Because cannabis and its products are classified as Schedule 1 drugs according to the US Drug Enforcement Agency (DEA), a product that garners FDA approval must also be reviewed by DEA for scheduling recommendations. To that end, FDA usually provides DEA with a scientific and medical evaluation to help with scheduling.  Scheduling classification is important because it affects the controls necessary for prescribing, supplying, or storing the product.  At present cannabis’ Schedule 1 status means that it and any products derived from it have no medicinal value or benefit and consequently are illegal in the US.  Nevertheless, it is extremely likely that any newly approved cannabis-based pharmaceuticals  will be rescheduled as Schedule II or Schedule III drugs as was  FDA’s previous experience with nabilone, dronabinol and Syndros.  That said, permanently removing  cannabis and its products form the Schedule 1 list would  undoubtedly help to speed development and subsequent regulatory approval of potentially life-altering cannabis-based pharmaceuticals.

References

  1. Ladin, DA, Soliman E, Griffin L and Van Dross, R. Preclinical and clinical assessment of cannabinoids as anti-cancer agents. Front Pharmacol. Oct. 2016; 7: 361 DOI: 10.3389/fphar.2016.00361
  2. Fijal, K, Filip M. Clinical/therapeutic approaches for cannabinoid ligands in central and peripheral nervous system diseases: mini review. Clin Neuropharmacol 2016; 39:94-101.
  3. Mintz CS, Fabrizio AJ, Nison E. Cannabis-Derived Pharmaceuticals. J. Comm. Biotechnol. 2015; 21:16-30.

 

Commercializing Cannabis-Derived Pharmaceuticals: Legal and Regulatory Challenges

The current regulatory and legal landscape for cannabis and cannabis-derived products is extremely difficult and fraught with numerous challenges. For example, in the US, cannabis and products derived from it (including hemp) are federally classified as Schedule I drugs according to the US Controlled Substances Act (1). This means that cannabis and its products have been deemed to have “no currently accepted medical use in treatment in the US” (heroin and LSD are also schedule I drugs), are harmful and consequently, are illegal (2).

Not surprisingly, its Schedule 1 classification has seriously hindered cannabis research in the US and made it extremely challenging for drug companies developing cannabis-derived pharmaceutical products (3). However, over the past decade or so, 29 states including the District of Columbia have enacted legislation that permits some form of cannabis consumption for medical purposes (4). Yet, despite this, cannabis and products derived from it remain illegal at the federal level and during interstate transport (even between states where medical marijuana has been legalized) is illegal and criminally punishable (2).

The confusion regarding cannabis use at the state and federal levels has given rise to two distinct types of companies that are attempting to commercialize cannabis (and products derived from it) for medicinal purposes. The first of these are commonly referred to as medical marijuana or medical cannabis companies. Typically, products from these companies are botanical extracts or actual plant materials derived from specific cannabis strains with anecdotally-reported medicinal properties that can be topically applied, ingested, smoked or vaporized. Patients require a “prescription” (card) from a state-licensed physician to obtain medical marijuana and it can only be used in states that permit consumption of cannabis for medical purposes. It is important to note, that while a prescription is required for medical cannabis use, these products do not require human clinical testing for safety, tolerability and efficacy (like other prescription drugs) prior to their sale in states where medical marijuana is legal.

In contrast with medical marijuana companies, biopharmaceutical companies including GW Pharma, Zynerba, Insys, Kannalife, Aphios and others (Table 1) are committed to developing cannabis-derived pharmaceuticals using conventional US Food and Drug Administration regulatory approval pathways. UK-based GW Pharma is the clear leader in cannabis-derived pharmaceutical space—its flagship product Sativex®, a plant extract, has been approved as a treatment for cancer-related pain and MS spasticity in 27 countries outside the US (5).

While the business case for developing pharmaceutical cannabis-derived pharmaceuticals is a sound one, the time and cost necessary for regulatory approval will be much greater than that for commercializing medical marijuana. At present, the United State Food and Drug Administration (FDA) has signaled a willingness to review new drug applications for cannabis-based pharmaceuticals (6). However, the agency has yet to issue definitive guidance for regulatory approval of these products and to date has not approved any application for cannabis-based products (6). Nevertheless, garnering FDA regulatory approval for cannabis–derived pharmaceuticals may offer several competitive advantages over numerous medical marijuana products that currently dominate the US market.

First, the average cost per patient of Sativex® to treat MS spasticity in countries where it has been approved has been estimated to be roughly $16,000 (6). Several studies indicate  (7, 8) that the high price of Sativex® will make it unlikely to be considered cost effective by regulators in countries with government-mandated national formularies like the UK, Ireland and Australia. However, this should not be an impediment in the US market because the federal government does not set drug prices and third-party payers dictate formulary placement and set drug reimbursement rates.

Second, unlike medical marijuana (which as previously state is a Schedule 1 drug), FDA approved cannabis-based pharmaceuticals like dronabinol and nabilone have been classified or reclassified as Schedule 2 (opioids) or Schedule 3 (codeine) drugs (5, 9). Federal regulators are likely to apply the same scheduling criteria to the next generation of FDA-approved cannabis-derived pharmaceuticals like Sativex® and others. Rescheduling will effectively allow these products to compete with medical marijuana because unlike medical marijuana—which is legal in only 29 states and cannot be transported across state borders—approved cannabis-derived pharmaceuticals can be legally prescribed, sold and used in all 50 states and US territories.

Finally, and perhaps most importantly, physicians may be inclined to prescribe FDA-approved cannabis drugs as compared with medical marijuana because they have been evaluated in human clinical trials and officially deemed to be safe and effective treatments for specific therapeutic indications.. In marked contrast, medical marijuana can be prescribed and sold in states where it is legal without going through any formal drug review process. While this is unlikely to interfere with possible therapeutic benefits offered by medical cannabis questions concerning product safety, effectiveness and reproducibility about these products are likely to continue to  arise until industry best practices are implemented and standardized.

References

  1. https://www.deadiversion.usdoj.gov/21cfr/21usc/812.htm  Accessed July 17, 2017
  2. https://www.dea.gov/druginfo/ds.shtml  Accessed July 17, 2017
  3. https://www.brookings.edu/wp-content/uploads/2016/06/Ending-the-US-governments-war-on-medical-marijuana-research.pdf  Accessed July 17, 2017
  4. http://medicalmarijuana.procon.org/view.resource.php?resourceID=000881 Accessed July 17, 2017
  5. https://www.gwpharm.com/products-pipeline/sativex  Accessed July 17, 2017
  6. https://www.fda.gov/newsevents/publichealthfocus/ucm421163.htm  Accessed July 17, 2017
  7. Pharmacoeconomic NCF. Cost-effectiveness of Delta-9-tetrahydrocannabinol/cannabidiol (Sativex®) as add-on treatment, for symptom improvement in patients with moderate to severe spasticity due to MS who have not responded adequately to other antispasticity medication and who demonstrate clinically significant improvement in spasticity related symptoms during an initial trial of therapy. 2014. http://www.ncpe.ie/wp-content/uploads/2013/01/Summary-v1.pdf.
  8. Lu L, Pearce H, Roome C, Shearer J, Lang IA, Stein K. Cost effectiveness of oromucosal cannabis-based medicine (Sativex(R)) for spasticity in multiple sclerosis. PharmacoEconomics. Dec 1 2012;30(12):1157-1171.
  9. https://www.deadiversion.usdoj.gov/fed_regs/rules/1998/fr1105.htm  Accessed July 17, 2017

Treating Cancer-Related Symptoms with Cannabis

In the 1970s, purified and synthetic cannabinoids were being evaluated as palliative treatments for cancer related symptoms (1). One of the earliest recognized clinical indications for cannabinoids was cancer induced nausea and vomiting (CINV) [2].

A 1988 prospective open label trial found that inhaled cannabis effectively controlled CINV in 78% of 56 cancer patients who had inadequate control of nausea and vomiting with conventional anti-emetics (3). Also, a later report that evaluated 30 trials and over 1300 participants determined that synthetic THC molecules such as nabilone and dronabinol were more effective than conventional anti-emetics in controlling acute CINV (2). This led to the early approval of dronabinol and nabilone as treatments for CINV but their use as a treatment for CINV has not been widespread (2,3)

A quick search of the clinical trials site www.clinical trials.gov revealed that there are no US clinical trials currently underway to further evaluate the use of Cannabis as a treatment for CINV.  Moreover, there are no natural Cannabis products e.g. extracts, sprays etc, on the market today that have received US Food and Drug Administration (FDA) approval as a treatment for CINV.

Inhaled Cannabis, and extracts containing THC and CBD have been clinically found to be more effective in treating cancer-related neuropathic pain than placebo (3, 4) but their effectiveness compared with conventional pain medications is uncertain (2). Yet, despite this, GW Pharma’s Sativex® (an extract that contains 1:1 ratio of Δ-9-tetrahydrocannabinol (THC) and cannabidiol [CBD]) is an approved treatment for cancer-related pain in 27 countries outside of the US (5).

There are currently 4 US clinical trials in (various phases) that are underway to determine the effects on Sativex® on advanced cancer pain and chemotherapy-induced neuropathic pain (Table 1). Regulatory experts expect Sativex® to garner FDA approval for both indications.

References

  1. Guzman M, Duarte MJ, Blazquez C, et al. A pilot clinical study of Delta9-tetrahydrocannabinol in patients with recurrent glioblastoma multiforme. British Journal of Cancer 2006; 95:197-203.
  2. Tramer MR, Carroll D, Campbell FA, Reynolds DJ, Moore RA, McQuay HJ. Cannabinoids for control of chemotherapy induced nausea and vomiting: quantitative systematic review. BMJ 2002; 323:16-21.
  3. Bowles DW, O’Bryant CL, Camidge DR, Jimeno A. The intersection between cannabis and cancer in the United States. Critical Reviews in Oncology/Hematology 2012; 83:1-10
  4. Notcutt W, Price M, Miller R, et al.  Initial experiences with medicinal extracts of cannabis for chronic pain: results from 34 ‘N of 1’ studies. Anaesthesia 2004; 59:440-452.
  5. https://www.gwpharm.com/products-pipeline/sativex  Accessed July 12, 2017

 

Cannabis Extracts, Cannabinoids and Cancer Treatment

There is a growing body of evidence that cannabinoids may have anti-tumor and cancer–fighting effects (1, 2).

Numerous studies have demonstrated inhibition of tumor growth in vitro and in animal models of disease for a variety of cancers including glioblastoma, breast, prostate, thyroid, colon, skin, pancreatic, leukemia and lymphoma (3).

The exact mechanism by which cannabinoids exert their anti-tumor effects is thought to occur via suppression of proliferative cell signaling pathways, inhibition of angiogenesis (blood vessel formation) and cell migration, stimulation of apoptosis (programmed cell death) and induction of autophagy (intracellular degradation) [3, 4].  Interestingly, cannabinoid receptors CB1 and CB2 have been found in higher concentrations on tumor cells than on surrounding normal tissue for a variety of cancers (5, 6).  Also, several studies suggest that cannabinoids may selectively inhibit tumor cell growth and proliferation while sparing normal tissue (3, 7).

Although cannabinoids exhibit possible anti-tumor effects, only a single Phase 1  clinical trial that assessed the safety and efficacy of THC in 9 patients with treatment refractory glioblastoma multiforme has been published (8).

However, at present, there are only two Phase 2 clinical trials underway or completed to assess the effect of cannabis extracts on solid tumor growth (NCT02255292) and glioblastoma (NCT01812603).  Clearly, more clinical studies are necessary to determine whether or not Cannabis extracts or different cannabinoids (singly or in combination) can be used as safe and effective cancer treatments for solid tumors.

References

  1. Bowles DW, O’Bryant CL, Camidge DR, Jimeno A. (2012) The intersection between cannabis and cancer in the United States. Critical Reviews in Oncology/Hematology 83(1):1-10.
  2. Lynch ME, Campbell F. (2011) Cannabinoids for treatment of chronic non-cancer pain; a systematic review of randomized trials. British Journal of Clinical Pharmacology 72(5):735-744.
  3. Pisanti S, Malfitano AM, Grimaldi C, et al. (2009) Use of cannabinoid receptor agonists in cancer therapy as palliative and curative agents. Best Practice & Research. Clinical Endocrinology & Metabolism 23(1):117-131.
  4. Salazar M, Carracedo A, Salanueva IJ, et al. (2009) Cannabinoid action induces autophagy-mediated cell death through stimulation of ER stress in human glioma cells. The Journal of Clinical Investigation 119(5):1359-1372.
  5. Caffarel MM, Andradas C, Mira E, et al. (2010) Cannabinoids reduce ErbB2-driven breast cancer progression through Akt inhibition. Molecular Cancer 9:196.
  6. Qamri Z, Preet A, Nasser MW, et al. (2009) Synthetic cannabinoid receptor agonists inhibit tumor growth and metastasis of breast cancer. Molecular Cancer Therapeutics 8(11):3117-3129.
  7. Flygare J, Sander B. (2008) The endocannabinoid system in cancer-potential therapeutic target? Seminars in cancer biology 18(3):176-189.
  8. Guzman M, Duarte MJ, Blazquez C, et al. (2006) A pilot clinical study of Delta9-tetrahydrocannabinol in patients with recurrent glioblastoma multiforme. British Journal of Cancer 95(2):197-203.