Cannabis has a long history of medical use, dating back thousands of years. However, this all came to an end with the widespread global prohibition of the plant in the 20th century. In this time of prohibition, research into the compounds found within the plant was largely curtailed. Yet, an ongoing wave of medical cannabis legalisation is now underway, leading to patient access to cannabis-based medicines for a number of conditions.
Cannabis was rescheduled in the UK in November 2018, allowing for the medical use of the plant in some cases. One of the conditions for which medical cannabis has been approved in the UK is chemotherapy-induced nausea and vomiting (CINV).
What is Chemotherapy-Induced Nausea and Vomiting?
Receiving a cancer diagnosis is difficult and life-changing for anyone, and it can affect both the patient’s life and that of their families. One of the most commonly used treatments for cancer is chemotherapy, which is used to kill cancer cells that have spread or are at risk of spreading. There are a number of different kinds of chemotherapy.
Although chemotherapy can potentially reduce the size of tumours, and potentially reduce the risk of cancer returning, it may cause serious side effects. As well as killing cancer cells, chemotherapy can also kill healthy cells. This often leads to a number of secondary symptoms such as hair loss, an increased risk of getting infections, and nausea and vomiting.
As chemotherapy is a treatment utilised in many cancer types, adjunctive therapies that manage these side effects are also essential. The scientific community is constantly assessing options to improve cancer care. One of these avenues of research is the anti-emetic (effective against nausea and vomiting) potential of cannabinoids.
Current Research on the Anti-emetic Potential of Cannabinoids
A number of studies in recent years have gathered positive evidence for the use of cannabinoids such as THC and CBD in reducing nausea and vomiting. One recent study published in the Annals of Oncology journal focused, particularly on CINV.
The multi-centre, randomised, double-blinded, placebo-controlled, phase 2 trial aimed to evaluate the potential of a CBD:THC cannabis extract in preventing refractory CINV. The trial was carried out with a patient sample who experienced moderate-to-high CINV despite guideline-consistent anti-emetic prophylaxis. A total of 81 patients were randomised, given a preparation of oral CBD:THC capsules or a matching placebo. Data was collected over three treatment cycles.
What Were the Results?
This study found that a self-titrated preparation of 2.5mg CBD: 2.5mg THC given in addition to chemotherapy was associated with less nausea and vomiting compared to placebo. This treatment was also associated with moderate additional side effects such as sedation, dizziness, and disorientation.
However, the majority of participants (85%) preferred the THC:CBD treatment to placebo, demonstrating promise for the addition of cannabinoids as a treatment for CINV. An overall improvement in health-related quality of life was also observed in utility, however, the researchers caution that this improvement may not be clinically significant.
This study has added to existing evidence of the tolerability of cannabinoid preparations and provided precedence for further research in this area. The authors of this study plan to continue this research with a phase 3 parallel component of this trial, recruiting 170 CINV patients.