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NBIX: P2 Study in Tourette’s Syndrome Does Not Meet Primary Endpoint; P2b Study to Start Before End of 2017

By David Bautz, PhD


Business Update

T-Force Green Study Does Not Meet Primary Endpoint

The T-Force GREEN study was a Phase 2 study designed to evaluate the safety, tolerability, and efficacy of INGREZZA™ in children and adolescents with Tourette syndrome (TS) (NCT02679079). It was a randomized, double blind, placebo controlled, multi-dose, parallel group trial of approximately 90 children and adolescents. Patients received once-daily dosing of INGREZZA™ or placebo in a 1:1:1 fashion during a six-week treatment period. The primary endpoint of the study was the change in baseline of the Yale Global Tic Severity Scale (YGTSS) between placebo and active groups at the end of six weeks.

On May 23, 2017, the company (NASDAQ:NBIX) announced that the T-Force GREEN study did not meet the primary endpoint, however the company still believes it was a successful study as a large amount of data was compiled that will likely lead to future clinical success. An exposure-response analysis showed that the selected doses (which were not disclosed by the company) were below the therapeutic range for adequate tic reduction in the majority of patients. For those subjects with adequate exposure to drug there was a substantial reduction in tics (-11.3 to -13.7 points on the YGTSS). For subjects that did not have adequate exposure to drug, the reduction in tics was similar to placebo (-4.7 to -8.3 points on the YGTSS). 

Management is confident that with the knowledge gained from this trial they will be able to better design the next study to maximize the chance for a positive outcome. The company is hopeful to get a Phase 2b study underway before the end of 2017 that will likely include more patients and the same endpoint, but those parameters won’t be known for sure until after the company meets with the FDA to finalize the protocol. While the T-Force GREEN study took approximately one year to fully enroll, management believes that the next study could likely be enrolled in approximately six months, as there will not be any delays in getting study sites on-line as there was for the T-Force GREEN study. Administrative delays caused a number of sites to not be available to enroll patients until a few months after the T-Force GREEN study initiated, and since those same sites are likely to be used in the next study those delays will not be an issue.  


We’re disappointed that the T-Force GREEN study did not meet the primary endpoint, however we are encouraged by how hopeful the company sounds in regards to what was learned from the study that can be applied to the next trial. We have pushed the timelines for approval in TS back by a year due to what we view as a minor setback, however we believe TS continues to represent a significant opportunity for the company and are confident in management’s ability to optimize the next trial design for success. We have slightly lowered our fair value estimate to $80 per share, and view any pullback in the stock price as a good opportunity for long-term investors to acquire shares. 


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