Neurocrine Biosciences Inc. Announces Interim Results from Phase 3 KINECT‑DCP Study of Valbenazine in Dyskinetic Cerebral Palsy
Neurocrine Biosciences Inc. (NASDAQ: NBIX) released a statement on 25 December 2025 reporting the interim outcomes of its Phase 3 KINECT‑DCP trial evaluating valbenazine for the treatment of dyskinetic cerebral palsy (CP). The study, the largest double‑blind, placebo‑controlled investigation in this indication to date, enrolled 312 participants (pediatric and adult) across 38 sites worldwide and administered 14 weeks of treatment. Although the primary endpoint and key secondary endpoints were not met, the safety profile of valbenazine remained consistent with data from prior Phase 2 studies and its approved indication for tardive dyskinesia (Ingrezza®).
Study Design and Population
| Parameter | KINECT‑DCP |
|---|---|
| Design | Randomized, double‑blind, placebo‑controlled |
| Phase | 3 |
| Duration | 14 weeks |
| Participants | 312 (age 5–65 years) |
| Inclusion | Documented choreiform movements secondary to cerebral palsy, Modified Ashworth Scale ≥2 in at least one target muscle group |
| Exclusion | Severe hepatic impairment, concomitant use of CYP3A4 inhibitors/inducers, uncontrolled psychiatric disorder |
Randomization was stratified by age group (pediatric vs. adult) and baseline severity of choreiform movements. Valbenazine dosing was weight‑adjusted, ranging from 1 mg/day to 8 mg/day, with titration over the first four weeks.
Efficacy Outcomes
Primary Endpoint
The primary endpoint was the change from baseline to week 14 in the Unified Dyskinesia Rating Scale (UDRS) total score, a validated composite measure of dyskinetic severity. The mean change in the valbenazine group (−2.3 ± 5.1) did not differ significantly from the placebo group (−1.8 ± 4.9) (p = 0.42).
Key Secondary Endpoints
| Endpoint | Valbenazine (mean change) | Placebo (mean change) | p‑value |
|---|---|---|---|
| UDRS chorea sub‑scale | −1.9 ± 4.4 | −1.3 ± 4.1 | 0.35 |
| Pediatric Functional Independence Scale (PFIS) | +0.5 ± 1.7 | +0.4 ± 1.6 | 0.61 |
| Caregiver Global Impression of Change (CGIC) | 0.3 ± 1.2 | 0.2 ± 1.1 | 0.54 |
All key secondary outcomes failed to reach statistical significance, with effect sizes falling below the prespecified non‑inferiority margins.
Safety Profile
The safety data were consistent with the known profile of valbenazine. Adverse events (AEs) were reported in 46 % of the valbenazine cohort and 43 % of the placebo cohort. The most frequent AEs were somnolence (10 % vs. 8 %), headache (8 % vs. 6 %), and dizziness (7 % vs. 5 %). Serious adverse events (SAEs) occurred in 4 % of participants in the valbenazine group and 3 % in the placebo group; none were deemed related to the study drug. No deaths were reported, and no clinically significant changes were observed in hepatic transaminases or QTc interval.
Comparison to Ingrezza® Safety Data
The incidence of somnolence and extrapyramidal symptoms aligns with the Phase 3 safety database for Ingrezza® in tardive dyskinesia (approximately 9 % somnolence, 4 % extrapyramidal side effects). No new safety signals were identified, supporting the established tolerability of valbenazine across indications.
Regulatory Context
The KINECT‑DCP study was conducted in accordance with the FDA’s guidance on clinical trial design for rare disease indications, including the use of the Unified Dyskinesia Rating Scale as a primary efficacy endpoint. The data set will inform the next steps in the development program, including potential submission of a supplemental IND application for an expanded label if a new therapeutic window is identified.
The failure to meet efficacy milestones, coupled with the earlier setback in the Phase 3 Ingrezza® trial for dystonia, underscores the challenges inherent in translating dopaminergic modulation to diverse movement disorder phenotypes. Neurocrine has indicated that it will reassess its clinical strategy and may explore alternative dosing regimens, biomarker‑guided sub‑population enrichment, or combination therapy approaches in future studies.
Implications for Clinical Practice
While the current data do not support a regulatory approval of valbenazine for dyskinetic CP, clinicians should remain aware of the safety profile established in this and prior studies. The absence of a significant efficacy signal suggests limited benefit for the broader dyskinetic CP population, although exploratory analyses identified a nominal trend toward improvement in a small subset of participants with less severe choreiform movements (UDRS change < −2 points). Further research may clarify whether specific phenotypic or genetic markers predict responsiveness to valbenazine.
Conclusion
Neurocrine Biosciences Inc.’s Phase 3 KINECT‑DCP study did not achieve its primary or key secondary efficacy endpoints in the treatment of dyskinetic cerebral palsy. The safety profile remained consistent with known data for valbenazine, with no new concerns emerging. The company will reassess its development strategy in light of these findings and the broader challenges observed in its clinical pipeline.
