INGREZZA Demonstrates Nearly Two-Fold Higher VMAT2 Target Occupancy Than AUSTEDO XR in Head-to-Head Study
核心洞察
Neurocrine Biosciences presented the first head-to-head data comparing INGREZZA (valbenazine) to AUSTEDO XR (deutetrabenazine), showing INGREZZA achieved 76.5% VMAT2 (搜索) target occupancy versus 38.3% for AUSTEDO XR at therapeutic doses.
The study used positron emission tomography (PET) imaging in eight participants and demonstrated INGREZZA's superior target engagement may be related to its single high-affinity metabolite compared to AUSTEDO XR's multiple metabolites with lower VMAT2 (搜索) affinity.
VMAT2 (搜索) target occupancy is a key measurement associated with drug response in involuntary movement disorders, and the higher occupancy observed with INGREZZA may contribute to its robust clinical efficacy in tardive dyskinesia (搜索) and Huntington's disease (搜索) chorea (搜索) trials.
Neurocrine Biosciences has unveiled compelling head-to-head data demonstrating that INGREZZA (valbenazine) achieves significantly higher vesicular monoamine transporter 2 (搜索) (VMAT2 (搜索)) target occupancy compared to AUSTEDO XR (deutetrabenazine) at therapeutic doses. The findings, presented at the American College of Neuropsychopharmacology 64th Annual Meeting, represent the first direct comparison between these two VMAT2 inhibitors used to treat involuntary movement disorders.
Superior Target Engagement Demonstrated
The study utilized positron emission tomography (PET) imaging to evaluate VMAT2 (搜索) target occupancy following single doses of either INGREZZA (40 mg or 80 mg) or AUSTEDO XR (24 mg or 48 mg) in eight participants, with each completing four PET visits. Using a linear mixed-effects model, the primary analysis revealed a least squares mean VMAT2 occupancy of approximately 76.5% for INGREZZA compared with approximately 38.3% for AUSTEDO XR at therapeutic doses.
"In this head-to-head assessment, INGREZZA demonstrated approximately two-fold higher target occupancy compared with AUSTEDO XR at therapeutic doses," said Sanjay Keswani, M.D., Chief Medical Officer at Neurocrine Biosciences. "The significantly higher VMAT2 (搜索) occupancy observed with INGREZZA adds to the already established differences between VMAT2 inhibitors in pharmacologic and clinical profiles."
Pharmacokinetic Modeling Reveals Steady-State Advantages
Pharmacokinetic exposure modeling and calculated half-maximal effective concentration (EC50) values enabled estimates of steady-state target occupancy, further demonstrating INGREZZA's superior VMAT2 (搜索) engagement at therapeutic doses. The modeling suggested that INGREZZA's advantages persist under steady-state conditions, which may be clinically relevant for long-term treatment outcomes.
Mechanistic Insights Into Superior Performance
The superior target engagement observed with INGREZZA may be attributed to its single high-affinity metabolite, compared with AUSTEDO XR, which generates multiple metabolites, including those with lower VMAT2 (搜索) affinity. This pharmacological difference could explain the observed disparity in target occupancy and potentially contribute to differences in clinical efficacy between the two treatments.
VMAT2 (搜索) inhibition represents an established therapeutic target for hyperkinetic movement disorders, including tardive dyskinesia (搜索) and Huntington's disease (搜索) chorea (搜索). VMAT2 target occupancy serves as a key measurement thought to be associated with the level of drug response in these conditions, as higher occupancy indicates greater engagement of the target and more effective inhibition of excessive dopamine transmission associated with involuntary movements.
Clinical Implications for Movement Disorders
The data are consistent with Neurocrine's integrated understanding of INGREZZA's target occupancy and drug exposure concentrations observed in pivotal clinical trials. According to Keswani, "The high occupancy of INGREZZA may contribute to the robust early and sustained clinical efficacy consistently demonstrated in multiple tardive dyskinesia (搜索) and Huntington's disease (搜索) chorea (搜索) clinical trials."
Tardive dyskinesia (搜索) affects at least 800,000 adults in the U.S. and is characterized by uncontrolled, abnormal and repetitive movements of the face, torso and other body parts. The condition is associated with taking certain antipsychotic medications that help control dopamine receptors (搜索) in the brain. Huntington's disease (搜索) affects approximately 41,000 adults in the U.S., with more than 200,000 at risk of inheriting the disease.
Safety Profile Maintained
All doses of INGREZZA and AUSTEDO XR were generally well tolerated and consistent with the known safety profile of each compound. This finding is particularly important as it suggests that INGREZZA's superior target engagement does not come at the cost of increased adverse effects.
INGREZZA is a selective VMAT2 (搜索) inhibitor approved by the FDA for treating adults with tardive dyskinesia (搜索) and chorea (搜索) associated with Huntington's disease (搜索). The drug offers a therapeutic dose from day one with no required titration and is available in 40 mg, 60 mg, and 80 mg capsules, including a sprinkle formulation for patients with swallowing difficulties.