TABLE 2.
PET studies reporting D2 receptor occupancy and brexpiprazole (BXP) blood concentrations.
| No | Author, year | PET Tracer | Design | Subjects | Mean Dose (range) [mg/day] | Mean BXP Conc. (range) [ng/ml] | Mean Receptor Occupancy (%) | EC50 [ng/ml] | EC90 (estimated from EC50) [ng/ml] | Comment |
| 1 | (28) | [11C]raclopride | Cohort study with dose response PET of BXP after single doses (phase 1). Plasma samples measured with HPLC | N = 15; healthy volunteers; age 33.9 ± 6.8; 93.3% males | 2.68 (0.25–6) | 32.5 ± 25.8 | D2/3 (p and c): 0.25 mg: < 20; 2–4 mg: 59–75; 5–6 mg: 77–88 | 7.75 (c), 8.13 (p) | 69.8 (c), 73.2 (p) | BXP AUC and cmax increased with dose, no ADR observed in study. |
| 2 | (36) | [11C]-(+)-PHNO, [11C]CUMI101, [11C]MDL100907, [11C]DASB | Cohort study comparing patients at baseline (unmedicated) and medicated, trough serum conc. at steady-state measured with HPLC | N = 12; SCZ (DSM-4); age 42 ± 8; 58.3% males | 3.0 (1–4), at day 4–10 | 82 ± 59 (N = 7 from D2 diagram) |
D2/3: 47.7 ± 38.5 SERT: −3 ± 15 5-HT1A: 4 ± 6 5-HT2A: 36.5 ± 20.9 |
22 (s) | 198 (s) | Dose dependent binding for D2 and 5-HT2A receptors, not detectable for D3. EC50 from non-linear model. Values for other models ranged up to 52 ng/ml. |
c, cortex; p, putamen; s, striatum; t, thalamus; SCZ, Schizophrenia.