GW on fire: PhIII epilepsy data signals success ahead for first CBD drug

Image: Justin Gover, GW Pharma

The British company shooting to be the first to launch a drug derived from the cannabis plant just got a big nod from the scientific community, paving the way for what could be one of the biggest blockbuster launches of the year.

Peer-reviewed journal The Lancet published Phase III data on GW Pharmaceuticals’ cannabidiol med Epidiolex, which was studied in a kind of pediatric epilepsy called Lennox-Gastaut syndrome (LGS).

The drug is a pharmaceutical formulation of CBD, a compound derived from cannabis that lacks the psychotropic effects of THC. Although a synthetic version of THC was approved by the FDA back in the 1980s, this would be the first regulatory approval of a weed-derived pharmaceutical product, if approved.

GW trumpeted its promising PhIII data in LGS after the trial wrapped up back in 2016, but The Lancet’s validation is meaningful to both patients and investors, GW’s CEO Justin Gover tells me. That’s because Epidiolex is what biotech companies like to call a “pipeline in a product,” as it’s being tested in several epileptic indications. Success in a difficult-to-treat epilepsy such as LGS boosts investors’ confidence that the drug will perform well in other epileptic conditions. Wall Street has estimated peak sales could reach $800 million-plus, with bullish analysts predicting closer to $2 billion.

Of these indications GW is taking on, LGS is notoriously difficult to treat. LGS patients often develop a resistance to the treatments they’re on, which leads to patients taking several drugs at once.

“For this patient population, unfortunately patients have tried and failed multiple drugs — three drugs on average. The probability of seeing improvement from adding another anti-epileptic drug of a similar type is very low,” Gover said. “The importance of CBD in this context is that it represents a very different type of medication, with a different mechanism of action and a different side effect profile.”

In LGS, Epidiolex triggered a median reduction of 44% in drop seizures (the kind of seizures that send patients to the ground, often causing injury). The placebo group saw a reduction of 22%, by comparison. The p-value came in at 0.0135.

Mild to moderate adverse events showed up in 74 of the 86 patients on the drug, the most common being diarrhea, somnolence, pyrexia, decreased appetite, and vomiting. Twelve patients dropped out of the study, and one died. The Lancet paper notes the patient death “was considered unrelated to treatment.”

GW is testing Epidiolex in several epileptic indications, including Dravet syndrome and tuberous sclerosis complex.

Epidiolex has also shown equally notable effect against Dravet syndrome, in which it triggered a 39% mean reduction in convulsive seizures compared to 13% in the placebo group in late-stage trials.

Investors appear to be pleased with the data behind the potential drug franchise so far, as GW managed to raise $300 million in a public offering last month. Gover said the company is well capitalized, with a cash balance of just over $600 million. That money will go straight into the commercial launch of Epidiolex, FDA approval willing.

Applications have been submitted to both the FDA and the EMA for Epidiolex in LGS and Dravet syndrome. The PDUFA date in the US is June 27, while Gover expects to hear back on the European approval in 2019.

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Research Scientist - Immunology
Recursion Pharmaceuticals Salt Lake City, UT
Director of Operations
Atlas Venture Cambridge, MA

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