A phase 2 trial of Neurocrine’s Ingrezza in Tourette syndrome has missed its primary endpoint. The vesicular monoamine transporter 2 inhibitor failed to outperform placebo on a tic severity scale, but, with Neurocrine finding cause for optimism in a secondary endpoint, the company still sees a future for the candidate.
Investigators enrolled 124 patients with Tourette syndrome in the trial and randomized them to receive one of two doses of Ingrezza or a placebo. After eight weeks of treatment, the change from baseline against the Yale Global Tic Severity Scale (YGTSS) and other scales was evaluated.
This is where Ingrezza came unstuck. Ingrezza failed to outperform placebo against YGTSS, the primary endpoint. That left Neurocrine looking to secondary endpoints for positives. Management found one in the significant improvement against another symptom scale, the Clinical Global Impression of Change, but details are thin on the ground at this stage.
"At present, we are not disclosing specific details of this study in order to avoid the potential introduction of assessment bias in the ongoing phase 2 T-Force GREEN study of pediatric Tourette patients,” Neurocrine CEO Kevin Gorman said in a statement.
The extent to which the adult phase 2 data should color expectations for the pediatric study is a source of debate. Most pediatric Tourette patients see their symptoms fade away by adulthood, suggesting there may be differences between the diseases in each population. This could be seen as a reason for confidence heading into the pediatric readout, but it is tempered by other evidence.
“As specialists state that (generally speaking) the same meds are used (and often work) in each population, we think this evening's readout offers at least a moderately cautious readthrough on the likelihood that the pediatric study attains statistical success,” Leerink analysts wrote in a note to investors. Leerink cut its probability of success from 70% to 30%.
The pediatric phase 2 trial is one of several opportunities Neurocrine has to bounce back from the setback over the coming year. Over the next 12 months, Neurocrine expects to win approval for Ingrezza in tardive dyskinesia, kick off several trials and see its partner AbbVie file for approval of Elagolix in endometriosis and post phase 3 data in uterine fibroids.