GW makes history; now to meet the huge expectations


GW Pharma has made the history books it has waited so long to enter, gaining the first US FDA approval of a marijuana-derived drug. Epidiolex has been cleared to treat two very rare types of severe childhood epilepsy and, if sales forecasts are correct, is destined to be a huge success.

Analysts expect Epidiolex to be generating sales of $2.3bn by 2024, according to EvaluatePharma’s consensus of sellside numbers. These figures presumably discount any real competition from the unregulated medical marijuana industry, a growing fringe sector that has attracted much attention – and substantial funds – in the past few years.

It is hard to know exactly how much of a threat over-the-counter cannabinoid-based oils present to products like Epidiolex, which is also derived from cannabinoids, or CBD. In extremely serious diseases like Lennox-Gastaut and Dravet syndrome, the threat is presumably negligible, as patients and physicians would surely first turn to approved products.

Indeed, it was US physicians keen to establish a reliable supply of CBD that triggered the Epidiolex programme in 2012, GW Pharma told EP Vantage several years ago. CBD has long been recognised as potentially valuable anticonvulsant, but dependable sources were hard to find, as well as being fraught with legal implications, and GW was a company with years of experience (Interview – GW Pharma eyes breakthrough therapy as epilepsy data approach, May 9, 2014).

In the wake of GW’s approval both the company and the FDA have been moved to point out the differences between a product like Epidiolex and unregulated oils, which do not have to live up to the regulator’s tough rules on dose standardisation and manufacturing, or efficacy and safety. Indeed, in its announcement of Epidiolex’s approval the US regulator included a shot across the bows of would-be competitors, threatening action against illegal marketing of CBD-containing products making unproven medical claims.

Measuring the threat

Still, the fact that the FDA feels the need to make such statements suggests that the swelling medical marijuana sector is a threat, of sorts. With the financial community pinning substantial sales forecasts to Epidiolex, this is not an issue that GW can afford to disregard completely.

GW has yet to say what its new drug will cost – but it will be many times more expensive than over-the-counter products.

For parents with children with intractable epilepsy, it seems very unlikely that payers will refuse to foot the bill, particularly as the evidence of Epidiolex’s effectiveness is so profound. Tensions seem more likely to arise if GW or other traditional drug companies attempt to move approved cannabis-derived products into indications where the evidence of efficacy is weaker, or the need is less great.

At present, the biggest treatment areas for registered medical cannabis patients are pain management, anxiety, depression and sleep disorders. And executives from the medical marijuana sector have suggested that it is over-the-counter products – and companies with consumer units – that are likely to be in their sights (Vantage Point – Canada’s medical cannabis ambition no laughing matter, May 29, 2018).

GW learned the hard way about neurology drug development, having spent years trying to establish Sativex, another of its CBD-based products, as a treatment for pain and muscle spasticity. The product is approved in various ex-US territories in multiple sclerosis spasticity, but sales are minimal; meanwhile, three pivotal trials in the more lucrative cancer pain setting failed to find an efficacy signal.

Medical marijuana companies will find it no easier to establish effectiveness in CNS conditions, which are notoriously exposed to high placebo responses. GW has more or less exited large neurology areas like pain anyway, so the big question for the company is whether unregulated products present a threat in rare and serious conditions.

For now this remains unanswered. But after shouting so loud about the differences between Epidiolex and over-the-counter cannabis oils, GW will struggle to point the finger at medical marijuana players if sales fail to live up to its hopes.

To contact the writer of this story email Amy Brown in London at or follow @ByAmyBrown on Twitter

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