Phase 1 pharmacokinetic and safety study of soticlestat in participants with mild or moderate hepatic impairment or normal hepatic function.

This phase 1, open-label, three-arm study (NCT05098054) compared the pharmacokinetics and safety of soticlestat (TAK-935) in participants with hepatic impairment. Participants aged ≥18 to <75 years had moderate (Child-Pugh B) or mild (Child-Pugh A) hepatic impairment or normal hepatic function (matched to hepatic-impaired participants by sex, age, and body mass index). Soticlestat was administered as a single oral 300 mg dose. Pharmacokinetic parameters of soticlestat and its metabolites TAK-935-G (M3) and M-I were assessed and compared by group. The incidence of treatment-emergent adverse events (TEAEs) and other safety parameters were also monitored. The pharmacokinetic analyses comprised 35 participants. Participants with moderate hepatic impairment had lower proportions of bound and higher proportions of unbound soticlestat than participants with mild hepatic impairment and normal hepatic function. Total plasma soticlestat pharmacokinetic parameters (maximum observed concentration [Cmax], area under the concentration-time curve from time 0 to time of last quantifiable concentration [AUClast], and AUC from time 0 to infinity [AUC∞]) were approximately 115%, 216%, and 199% higher with moderate and approximately 45%, 35%, and 30% higher with mild hepatic impairment, respectively, than healthy matched participants. Moderate hepatic impairment decreased the liver's ability to metabolize soticlestat to M-I; glucuronidation to M3 was also affected. Mild hepatic impairment resulted in a lower total plasma M-I exposure, but glucuronidation was unaffected. TEAEs were similar across study arms, mild, and no new safety findings were observed. A soticlestat dose reduction is required for individuals with moderate but not mild hepatic impairment.

Effects of Strong Inhibition of Cytochrome P450 3A and UDP glucuronosyltransferase 1A9 and Strong Induction of Cytochrome P450 3A on the Pharmacokinetics, Safety, and Tolerability of Soticlestat: Two Drug-Drug Interaction Studies in Healthy Volunteers.

Two open-label, phase 1 studies (NCT05064449, NCT05098041) investigated the effects of cytochrome P450 (CYP) 3A inhibition (via itraconazole), UDP glucuronosyltransferase (UGT) 1A9 inhibition (via mefenamic acid), and CYP3A induction (via rifampin) on the pharmacokinetics of soticlestat and its metabolites M-I and M3. In period 1 of both studies, participants received a single dose of soticlestat 300 mg. In period 2, participants received itraconazole on days 1-11 and soticlestat 300 mg on day 5 (itraconazole/mefenamic acid study; part 1); mefenamic acid on days 1-7 and soticlestat 300 mg on day 2 (itraconazole/mefenamic acid study; part 2); or rifampin on days 1-13 and soticlestat 300 mg on day 11 (rifampin study). Twenty-eight healthy adults participated in the itraconazole/mefenamic acid study (14 per part) and 15 participated in the rifampin study (mean age, 38.1-40.7 years; male, 79-93%). For maximum observed concentration, the geometric mean ratios (GMRs) of soticlestat + itraconazole, mefenamic acid, or rifampin to soticlestat alone were 116.6%, 107.3%, and 13.2%, respectively, for soticlestat; 10.7%, 118.0%, and 266.1%, respectively, for M-I, and 104.6%, 88.2%, and 66.6%, respectively, for M3. For area under the curve from time 0 to infinity, the corresponding GMRs were 124.0%, 100.6%, and 16.4% for soticlestat; 13.3%, 117.0%, and 180.8% for M-I; and 120.3%, 92.6%, and 58.4% for M3. Soticlestat can be administered with strong CYP3A and UGT1A9 inhibitors, but not strong CYP3A inducers (except for antiseizure medications, which will be further evaluated in ongoing phase 3 studies). In both studies, all treatment-emergent adverse events were mild or moderate. SIGNIFICANCE STATEMENT: These drug-drug interaction studies improve our understanding of the potential changes that may arise in soticlestat exposure in patients being treated with CYP3A inhibitors, UGT1A9 inhibitors, or CYP3A inducers. The results build on findings from previously published soticlestat studies and provide important information to help guide clinical practice. Soticlestat has shown positive phase 2 results and is currently in phase 3 development for the treatment of seizures in patients with Dravet syndrome and Lennox-Gastaut syndrome.