INTERACT: a randomized phase 2 study of the DAAO inhibitor luvadaxistat in adults with schizophrenia.

Deficits in N-methyl-d-aspartate receptor (NMDAR) signaling are implicated in the pathogenesis of schizophrenia. Luvadaxistat (TAK-831/NBI-1065844) is an investigational d-amino acid oxidase (DAAO) inhibitor that increases d-serine levels at NMDAR coagonist sites. INTERACT is a phase 2 randomized, placebo-controlled study that evaluated the efficacy and safety of three doses of luvadaxistat, covering a range of DAAO occupancy and d-serine levels, in patients with schizophrenia with persistent negative symptoms. The study included a 14-day, single-blinded placebo run-in period and a 12-week, double-blinded treatment period. The primary efficacy endpoint was the 12-week change from baseline in Positive and Negative Syndrome Scale-Negative Symptom Factor Score (PANSS NSFS). Secondary efficacy endpoints included the 12-week changes from baseline in Brief Assessment of Cognition in Schizophrenia (BACS) score and Schizophrenia Cognition Rating Scale (SCoRS) score. Safety endpoints included adverse event assessments. The full analysis set included all randomized patients (N = 256 [placebo, n = 87; luvadaxistat 50 mg, n = 58; 125 mg, n = 56; 500 mg, n = 55]); 228 patients completed the study. No significant improvements in PANSS NSFS were observed at any dose versus placebo at week 12. Improvements were observed with luvadaxistat 50 mg versus placebo in cognitive endpoints: BACS composite score (nominal one-sided p = 0.031) and SCoRS interviewer total score (nominal one-sided p = 0.011). Luvadaxistat did not significantly improve negative symptoms of schizophrenia. However, luvadaxistat 50 mg met the prespecified secondary endpoints for cognitive performance (BACS) and function (SCoRS), warranting further investigation in patients with cognitive impairment associated with schizophrenia. Luvadaxistat was well-tolerated in INTERACT, with no new safety signals observed. ClinicalTrials.gov: NCT03382639.

Effects of the selective AMPA modulator NBI-1065845 on the pharmacokinetics of midazolam or ethinyl estradiol-levonorgestrel in healthy adults.

This parallel-arm, phase I study investigated the potential cytochrome P450 (CYP)3A induction effect of NBI-1065845 (TAK-653), an investigational α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor potentiator in phase II development for major depressive disorder. The midazolam treatment arm received the sensitive CYP3A substrate midazolam on Day 1, followed by NBI-1065845 alone on Days 5-13; on Day 14, NBI-1065845 was administered with midazolam, then NBI-1065845 alone on Day 15. The oral contraceptive treatment arm received ethinyl estradiol-levonorgestrel on Day 1, then NBI-1065845 alone on Days 5-13; on Day 14, NBI-1065845 was administered with ethinyl estradiol-levonorgestrel, then NBI-1065845 alone on Days 15-17. Blood samples were collected for pharmacokinetic analyses. The midazolam treatment arm comprised 14 men and 4 women, of whom 16 completed the study. Sixteen of the 17 healthy women completed the oral contraceptive treatment arm. After multiple daily doses of NBI-1065845, the geometric mean ratios (GMRs) (90% confidence interval) for maximum observed concentration were: midazolam, 0.94 (0.79-1.13); ethinyl estradiol, 1.00 (0.87-1.15); and levonorgestrel, 0.99 (0.87-1.13). For area under the plasma concentration-time curve (AUC) from time 0 to infinity, the GMRs were as follows: midazolam, 0.88 (0.78-0.98); and ethinyl estradiol, 1.01 (0.88-1.15). For levonorgestrel, the GMR for AUC from time 0 to the last quantifiable concentration was 0.87 (0.78-0.96). These findings indicate that NBI-1065845 is not a CYP3A inducer and support its administration with CYP3A substrates. NBI-1065845 was generally well tolerated, with no new safety signals observed after coadministration of midazolam, ethinyl estradiol, or levonorgestrel.