Lurasitor 40/Lurasitor 80 Mechanism of Action

Antipsychotic (Indole Derivative).
Pharmacology: Mechanism of Action: The mechanism of action of lurasidone in the treatment of schizophrenia and bipolar depression is unknown. However, its efficacy in schizophrenia and bipolar depression could be mediated through a combination of central dopamine Type 2 (D2) and serotonin Type 2 (5HT2A) receptor antagonism.
Pharmacodynamics: Lurasidone is an antagonist with high affinity binding at the dopamine D2 receptors (Ki of 1 nM) and the serotonin 5-HT2A (Ki of 0.5 nM) and 5-HT7 (Ki of 0.5 nM) receptors. It also binds with moderate affinity to the human α2C adrenergic receptors (Ki of 11 nM), is a partial agonist at serotonin 5-HT1A (Ki=6.4 nM) receptors, and is an antagonist at the α2A adrenergic receptors (Ki=41 nM). Lurasidone exhibits little or no affinity for histamine H1 and muscarinic M1 receptors (IC50 >1,000 nM).
ECG Changes: The effects of lurasidone hydrochloride on the QTc interval were reported in a randomized, double- blind, multiple-dose, parallel-dedicated thorough QT study in 43 patients with schizophrenia or schizoaffective disorder, who were treated with lurasidone hydrochloride doses of 120 mg daily, 600 mg daily and completed the study. The maximum mean (upper 1-sided, 95% CI) increase in baseline-adjusted QTc intervals based on individual correction method (QTcI) was 7.5 (11.7) ms and 4.6 (9.5) ms, for the 120 mg and 600 mg dose groups respectively, reported at 2 to 4 hours after dosing. In this study, there was no apparent dose (exposure)-response relationship.
In reported short-term, placebo-controlled studies in schizophrenia and bipolar depression, no post-baseline QT prolongations exceeding 500 msec were reported in patients treated with lurasidone hydrochloride or placebo.
Pharmacokinetics: Adults: The activity of lurasidone hydrochloride is primarily due to the parent drug. The pharmacokinetics of lurasidone hydrochloride is dose-proportional within a total daily dose range of 20 mg to 160 mg. Steady-state concentrations of lurasidone hydrochloride are reached within 7 days of starting lurasidone hydrochloride.Following administration of 40 mg of lurasidone hydrochloride, the mean (%CV) elimination half-life was 18 (7) hours.
Absorption and Distribution: Lurasidone hydrochloride is absorbed and reaches peak serum concentrations in approximately 1 to 3 hours. It is estimated that 9 to 19% of an administered dose is absorbed. Following administration of 40 mg of lurasidone hydrochloride, the mean (%CV) apparent volume of distribution was 6173 (17.2) L. Lurasidone hydrochloride is highly bound (~99%) to serum proteins.In a reported food effect study, lurasidone hydrochloride mean Cmax and AUC were about 3-times and 2-times, respectively, when administered with food compared to the levels observed under fasting conditions. Lurasidone hydrochloride exposure was not affected as meal size was increased from 350 to 1000 calories and was independent of meal fat content.
Metabolism and Elimination: Lurasidone hydrochloride is metabolized mainly via CYP3A4. The major biotransformation pathways are oxidative N-dealkylation, hydroxylation of norbornane ring, and S-oxidation. Lurasidone hydrochloride is metabolized into two active metabolites (ID-14283 and ID-14326) and two major non-active metabolites (ID-20219 and ID-20220). Based on in vitro studies, lurasidone hydrochloride is not a substrate of CYP1A1, CYP1A2, CYP2A6, CYP4A11, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6 or CYP2E1 enzymes. Because lurasidone hydrochloride is not a substrate for CYP1A2, smoking is not expected to have an effect on the pharmacokinetics of lurasidone hydrochloride.
Transporter proteins: Reported in vitro studies suggest lurasidone hydrochloride is not a substrate of OATP1B1 or OATP1B3, however, is probably a substrate of P-gp and BCRP. In vitro studies indicate that lurasidone hydrochloride is not expected to inhibit transporters OATP1B1, OATP1B3, OCT1, OCT2, OAT1, OAT3, MATE1, MATE2-K and BSEP at clinically relevant concentrations. Lurasidone hydrochloride is not a clinically significant inhibitor of P-gp. However, it may inhibit BCRP.
Total excretion of radioactivity in urine and feces combined was approximately 89%, with about 80% recovered in feces and 9% recovered in urine, after a single dose of [14C]-labeled lurasidone hydrochloride.
Following administration of 40 mg of lurasidone hydrochloride, the mean (%CV) apparent clearance was 3902 (18.0) mL/min.