In a 2021 study published in the British Journal of Cancer Professor Susan Short studied the impacts of combining Sativex (an oral spray containing a combination of cannabinoids) with temozolomide (a form of chemotherapy treatment) on recurrent glioblastoma.
Glioblastoma (GBM) is the most common malignant primary brain tumour in adults. The study notes that there’s an estimated incidence of 3.2 per 100,000 and a 5-year survival rate of less than 6%.
Although the study was too small to confirm a survival benefit for those involved, initial results did show that more patients were alive after 1 year when taking the Sativex/temozolomide treatment vs the placebo.
The trial for this study was conducted across 10 sites (7 in the UK, 3 in Germany) between January 2014 and August 2016.
Because of the variability in the PKs an pharmacodynamics of nabiximols, the dosing was individualised to the patients of between 3 – 12 sprays per day, based on a dose-ranging trial that showed a favourable risk/benefit profile in patients with chronic pain – if a patient experienced unacceptable side effects the dose was reduced until the issues were resolved.
Patients were instructed to take nabiximols, or the placebo, alongside their chemotherapy treatment at their personalised dosage for 1 year – or until they withdrew from the trial.
The trial was split across 2 parts, in part 1 six patients enrolled in the study and received nabiximols spray. In Part 2 of the trial there were twenty-one patents randomised. Of these twelve received nabiximols and nine received the placebo.
In part 1, once personalised dosage had been established, patients took a mean of 6 sprays per day which ranges from 3.3 sprays to 12 sprays per day. The mean exposure for this treatment was 16 weeks.
In part 2, patients taking the nabiximols combination took around 7.5 sprays per day, ranging from 2-12 sprays. The mean duration of exposure in this group was 24.9 weeks.
As we’ve already alluded to, researchers overseeing the phase 1 study did observe an increase in survival rates exceeding 1 year in patients taking the combined Sativex and temozolomide treatment (83% vs 44% for placebo patients). It should be noted however, that this sample size in this particular study is too small to confirm a definitive link between the combination of Sativex and temozolomide and the increasing of survivability – however this research, and the observed survival differences do support further exploration in a future adequately powered randomised controlled trial.
Looking to the future
Professor Susan Short has outlined phase 2 of the clinical trial which will continue the scope of the initial study – and to ascertain whether combining Sativex with temozolomide works better than simply using temozolomide alone, in turn helping patients live longer.
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