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Clinical Trials

Zynerba halts development of THC prodrug ZYN001

PBR Staff Writer Published 06 July 2018

A failure in a phase 1 clinical program has forced Zynerba Pharmaceuticals to stop development of ZYN001, its pro-drug of tetrahydrocannabinol (THC) intended for the treatment of neuropsychiatric disorders including Tourette Syndrome.

The Pennsylvania-based cannabinoid-based drug developer reported that the drug, which is delivered via a transdermal patch, could not achieve the target blood levels of 5 to 15ng/ml THC in the early-stage trial.

The phase 1 trial, which was a single and multiple dose, placebo-controlled first-in-man study, evaluated the safety and pharmacokinetics of ZYN001 in single and multiple doses across several formulations in healthy volunteers.

Zynerba revealed that various formulations and patch wear times ranging from 24 hours to 14 days were evaluated in 60 healthy subjects, who were randomized to receive either ZYN001 or placebo.

The drugmaker said that based on the data from ZYN001’s phase 1 trial, it will rather focus its development efforts and investments on the development of ZYN002 for the treatment of Fragile X syndrome, developmental and epileptic encephalopathy (DEE) and adult refractory epilepsy programs.

The company anticipates stopping further development of ZYN001 will extend its cash runway into the second half of 2019.

Zynerba said it now believes that the cash and cash equivalent position of $52.1m as of 31 March 2018 is sufficient to fund operations and capital needs into the second half of 2019.

While ZYN001 is a THC pro-drug patch, ZYN002 is a pharmaceutically-produced CBD, formulated as a permeation-enhanced gel for transdermal delivery for the treatment of neuropsychiatric disorders.

In late April, Zynerba reported positive results for ZYN002 in a STAR 2 (Synthetic Transdermal CAnnabidiol for the TReatment of Epilepsy) 24-month open label extension study. The trial evaluated the ZYN002 cannabidiol (CBD) transdermal gel in adult patients with focal seizures.

Zynerba said that in the STAR 2 trial, longer term exposure to ZYN002 resulted in significant improvements in seizure frequency among all the patients treated with the gel.

Image: Zynerba’s ZYN001 failed to deliver the desired results in a phase 1 trial. Photo: courtesy of jk1991/