Neurocrine's Tourette's trial gets a red light
- Neurocrine Biosciences remains upbeat as Ingrezza (valbenazine), its clinical-stage Tourette's syndrome drug, does not reach its primary endpoint in the Phase 2 T Force GREEN study involving 98 children and adolescents. Ingrezza is already approved in the U.S. for the movement disorder tardive dyskinesia.
- While the drug was no better than placebo at reducing the Yale Global Tic Severity Scale (YGTSS) score at week 6, exposure-response analysis suggested that the studied doses were too low. Patients with "pharmaceutical exposure in the appropriate range" showed reductions of 11.3 to 13.7 points, whereas those in the "sub-therapeutic range" showed reductions of 4.7 to 8.3 points, similar to placebo.
- A Phase 2b Tourette's study, following discussions with this FDA, is planned before the end of 2017, though Neurocrine is not giving firm guidance on timelines or study design. Discussions with the FDA will also include questions about the requirements for a pivotal study.
"The T Force GREEN study showed that we underestimated the Ingrezza dose needed for the pediatric population but also provided us with a clear-cut view into the level of dosing required for future studies," said Christopher F. O'Brien, CMO at Neurocrine. "We have developed a complete exposure-response model from this study that we believe accurately defines the appropriate dose-range to be tested in the next clinical study."
Investors weren't as optimistic about the study. The stock dropped in after hours trading and continued its decline in the morning, falling 9% to trade below $49 per share.
Despite not meeting the primary endpoint, Neurocrine management said on a conference call last night that it plans talks with the Food and Drug Administration during 2017 and remains confident it could maintain its route towards the market without too much delay.
"We would like to have hit the home run with statistical significance, but short of that, it was an excellent study and has given us a lot of information," said CEO Kevin Gorman in a conference call on the news.
The company was cagey about the design of the planned Phase 2b study, citing competitive reasons, with O'Brien confirming that they would not change the endpoints and stating a number of times that details will not be available until after the discussion with the FDA, when more information will be posted on ClinicalTrials.gov.
When pressed on numbers, the executive would only reveal that more patients would likely be enrolled than in T Force GREEN. The enrollment for T Force GREEN took longer than expected as, according to O'Brien, not all investigator sites were online from day one, but enrollment for the planned Phase 2b study is expected to be faster.
"We now have identified the right subjects and the right investigators, and we now have a pediatric exposure-response analysis. We have also finished all the safety and toxicity studies, and the exposures are well within those of the approved drug. We have a broad therapeutic window to work in," said O'Brien.
Analysts at Jefferies have pushed their prediction of a U.S. launch in Tourette's back to 2021 from 2020, based on the need to run a Phase 2b trial.
Gorman added that the company hasn't pursued a launch in Europe and would not launch there alone, but there has been interest from other parties.
- Neurocrine Biosciences Statement
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