Clinical Trial in Spain Will Investigate the Role of Cannabis in Glioblastoma Treatment

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The 18-month trial will study the effects of a cannabis extract as part of treatment for brain cancer.

Announced earlier this month, a new clinical trial is underway to study the effects of cannabis on glioblastoma, a form of brain cancer (1,2). According to a recent press release (1), the Phase 1, open-label trial will be supported by a collaboration of several organizations and researchers. Canadian cannabis producer Tilray Medical will supply a THC:CBD 1:1 extract for the study, which will be conducted by scientists from the Spanish Research Group of Neuro-Oncology (GEINO) and the Complutense University Madrid (1). Laboratory research from the Cannabinoid Signalling Group team at the Complutense University Madrid has reportedly indicated that a combination of the cannabinoids THC and CBD can inhibit the growth of cancer cells (2). Thirty patients from eight specialized neuro-oncology medical facilities will receive the cannabis extract in combination with temozolomide and radiotherapy to treat their glioblastomas (1).

The trial, which is being conducted in Spain, began on September 5th, 2023 and is being led by coordinating researcher Dr. Juan Manuel Sepúlveda Sánchez from GEINO and the Hospital Universitario 12 de Octubre in Madrid (1,3).


“Biological evidence has been accumulating for more than 15 years that cannabinoids have anti-tumor activity in the most aggressive brain tumors, glioblastomas,” stated Dr. Sepúlveda (1). “However, no clinical trials have been conducted to prove this hypothesis in patients. With this clinical trial, we can finally study the effect of cannabinoids on tumors that have not received active treatment. With this trial, we are helping to give our patients a new option, but also to open a therapeutic avenue.”

Funding for the trial was provided by the Medical Cannabis Bike Tour, a charity which began raising funds for Complutense Madrid University team in 2013 (1).

“What makes this extra special is that this trial is a special collaboration between the medical cannabis community and the scientific sector, for the benefit of science,” the Medical Cannabis Bike Tour stated on their website (2). “This first trial will test that the treatment is safe, monitor response and survival rates (compared to traditional treatments), and measure improvements to quality of life.”


  1. Tilray Medical Supports New Clinical Trial to Study Medical Cannabis in Glioblastoma Cancer Treatment. GlobeNewsWire. October 16, 2023.
  2. Cycle powered cannabis clinical trial starts! (accessed Oct 17, 2023).
  3. GEINO 1601: a clinical trial begins to study the effect of cannabinoids in patients with glioblastoma (accessed Oct 17, 2023).