GW’s cannabis drug Epidiolex sees ‘huge influx’ of patients as new data sets up expansion

Sales of GW Pharma’s cannabis drug Epidiolex surged on its first full quarter on the market. (Pixabay)

GW Pharmaceuticals’ cannabis-based seizure drug Epidiolex is off to an exceptionally good start—so good that executives tried hard to dampen investor enthusiasm for the rest of the year by pointing to some “unusual launch dynamics.”

In its first full quarter on the market, Epidiolex racked up sales of $33.5 million, more than double analyst expectations of $16 million. And positive results from a phase 3 trial have put it on track to an important market expansion.

Since its launch last November, more 7,600 patients have received an Epidiolex prescription, and more than 1,900 doctors have prescribed the med, Julian Gangolli, who just retired as GW’s commercial chief, said on the company’s first-quarter earnings call, calling it “an unusually high rate of new-patient acquisition.”

Given the “huge influx of patients,” Gangolli cautioned about looking at quarter-on-quarter growth when Q2 results come around. Some unusual factors played into the Q1 beat that neither execs nor analysts seem to have expected.

First, pent-up demand. Prescriptions from previously diagnosed patients waiting for the launch delivered a surge of scripts carrying into Q1, Gangolli said. Plus, many commercial and state Medicaid programs only implemented coverage decisions in January, pushing scripts into the new year, he said.

GW itself helped turn up the valve by increasing the number of specialty pharmacies in its network and cutting the time to fill the initial prescriptions from over a month at launch to an average of two weeks in Q1. And more than 75% of some 900-plus clinical trial patients have transitioned to the commercial product, a faster-than-expected conversion that contributed to the initial surge in scripts, Gangolli said.

The company is also seeing a higher percentage of adult patients than it had expected, which Gangolli attributed to payer deals that feature less restrictive prior authorization requirements, or no prior authorization at all. Because Epidiolex’s dosage level is weight-based, more adult patients could also translate into bigger sales.

After some rollover effects extending into February, new prescriptions have slowed, Evercore ISI analyst Josh Schimmer noted in a Saturday report to clients, citing IQVIA data.

“Our expectation was and continues to be that physicians will prescribe to gain experience with an initial set of patients and observe those patients over a four- to six-month period as to therapeutic effect, before determining how to utilize Epidiolex in a broader set of patients,” Gangolli said, adding that it has now entered that evaluation period.

RELATED: After November rollout, GW Pharma says Epidiolex positioned for strong growth

In addition, patients are given Epidiolex on a gradually increasing dosage level, starting from 2.5 mg/kg taken twice daily and then staying on 5 mg/kg twice daily for some time before titrating up to as high as 20 mg/kg. Gangolli said the observation period will likely last several months for existing patients, and the likelihood of their reaching maximum dosages is “relatively remote.”

Epidiolex is approved to treat two rare forms of epilepsy, Lennox-Gastuat syndrome and Dravet syndrome, in patients 2 years of age or older. There's obviously some off-label use in other indications, though, Schimmer figures. Because Epidiolex’s label says “seizures associated” with LGS or Dravet, “some physicians have taken to imply a potential use to the broader refractory epilepsy population,” the Evercore analyst said. CEO Justin Gover said Monday that the company couldn't discuss off-label use, apart from some anecdotal off-label successes.

But Epidiolex could boast an official new indication soon. Results from a phase 3 trial of Epidiolex in the rare childhood-onset condition tuberous sclerosis complex (TSC) showed the drug could significantly cut the number of seizures by 48.6% on the 25 mg/kg/day dose or 47.5% on double that dosage level over 16 weeks. Patients on placebo only saw a 26.5% reduction, GW reported Monday. The most common side effects lined up with those seen in the drug's four pivotal studies.

The company now plans to file for that new approval in the fourth quarter, aiming for a potential launch in 2020. It estimates TSC affects 40,000 to 80,000 people in the U.S. and about 1 million to 2 million worldwide. That means a TSC approval would roughly double Epidiolex's current market, J.P. Morgan analyst Cory Kasimov figures.

“What [a TSC nod] does from a commercial perspective, it allows us to go into these very dedicated TSC clinics that have large patient populations,” Gover said. “Many of those physicians are the same physicians that are treating the other refractory epilepsies.”

Now, the U.S. expansion will fall on the shoulders of new U.S. commercial chief Darren Cline, who led the Adcetris launch at Seattle Genetics, and prior to that, the Soliris launch at Alexion Pharmaceuticals.

Outside of the U.S., GW is awaiting a European Medicines Agency opinion soon. With its European commercial organization almost fully in place, the company is eyeing an early commercial launch in France, Germany and the U.K.