Neurocrine Biosciences (NASDAQ:NBIX) presented the first head-to-head imaging data on Thursday comparing the brain-binding potency of the two leading treatments for involuntary movement disorders.
Using Positron Emission Tomography (PET) scans, the study demonstrated that Ingrezza (valbenazine) achieved significantly higher target occupancy of the vesicular monoamine transporter 2 (VMAT2) than Teva’s Austedo XR (deutetrabenazine) at therapeutic doses.
VMAT2 occupancy is a critical metric in neurology, as it measures how effectively a drug engages the "pumps" that regulate dopamine release.
By inhibiting these pumps, these drugs reduce the excessive dopamine signaling that causes the jerking or twitching movements associated with tardive dyskinesia and Huntington's disease chorea.
The primary analysis evaluated participants after single doses, showing a stark difference in immediate potency with a least-squares mean VMAT2 occupancy of approximately 76.5% for Ingrezza compared to 38.3% for Austedo XR.
The study also used pharmacokinetic modeling to estimate "steady-state" occupancy—the level of drug binding maintained after daily use.
Ingrezza continued to lead, showing 83% and 92% occupancy for its 40 mg and 80 mg doses respectively, while Austedo XR trailed with 54% and 70% occupancy for its 24 mg and 48 mg doses.
The findings, presented at the American College of Neuropsychopharmacology (ACNP) Annual Meeting in the Bahamas, provide a significant marketing advantage for Neurocrine.
While both medications were reported to be generally well tolerated, the data suggests that Ingrezza provides more robust target engagement at standard clinical doses.
This differentiation is expected to bolster Neurocrine's competitive position in a market where physicians prioritize consistent symptom control and simple dosing regimens.