GW Stops ARCH Phase 3 Trial Testing Epidiolex in Children, Adolescents, Due to COVID-19

Due to the unprecedented challenges caused by the ongoing COVID-19 pandemic, GW Pharmaceutics has stopped the ARCH Phase 3 clinical trial evaluating the oral cannabidiol (CBD) solution Epidiolex in children and adolescents with Rett syndrome.

The decision was made after evaluating the progress of the study (NCT03848832) — which was ongoing in the U.S., the U.K., Spain, and Italy — and the impact of the pandemic on patients, caregivers, and research sites, the company said.

Patients already participating in the study, or awaiting entry into its extension part, are advised to contact their physicians to discuss their options.

“We understand that this news will be met with disappointment by the community,” GW Pharmaceuticals said in a letter addressed to the Rett syndrome community. “Unfortunately, the significant challenges to conducting this trial have been magnified by the pandemic leading to the conclusion that it is no longer feasible to conduct this study.”

The data collected so far were blinded — meaning neither researchers nor participants knew which patients were receiving Epidiolex and which a placebo — and therefore not part of the decision to discontinue the trial.

CBD, the active ingredient of Epidiolex, is a compound extracted from the cannabis plant that does not have its mind-altering effects. The therapy is currently approved to treat seizures experienced by people with Lennox-Gastaut and Dravet syndromes. 

Based on preclinical results with a compound similar to CBD, it was suggested that Epidiolex may treat motor and behavioral problems in people with Rett syndrome, whose disease is most commonly caused by mutations in the MECP2 gene. The resulting MeCP2 protein plays a key role in brain development and function.

Epidiolex is thought to induce the release of neurotransmitters — messengers in nerve-cell communication — that may have neuroprotective effects for Rett patients. 

The ARCH trial enrolled 252 girls between the ages of 2 and 18, who were randomly assigned to receive either 5 or 15 mg/kg of body weight per day of Epidiolex, or a placebo, twice daily for 24 weeks (almost six months). 

The primary outcome was a change in the Rett Syndrome Behaviour Questionnaire, a caregiver-completed assessment of the frequency of behavioral and emotional symptoms, in which higher scores represent greater symptom severity. Secondary goals included global assessments, as well as motor and sleep measures. The study was expected to be completed in September 2021.

“We are very grateful to the Rett community for their collaboration, partnership, and support of this project,” GW said in its letter. “We fully appreciate the great deal of effort and dedication by clinicians, study personnel and most importantly, patients and caregivers to support this trial.” 

“We recognize the significant unmet need currently experienced by individuals living with Rett syndrome and their families, and we are deeply disappointed that the study will not be able to continue,” the company said.