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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. [ABSTRACT FROM AUTHOR]

Glasdegib is approved for treating acute myeloid leukemia in elderly patients at 100 mg once daily in combination with low‐dose cytarabine. Exposure‐efficacy analysis showed that the survival benefit of glasdegib was not glasdegib exposure‐dependent. The relationship between glasdegib exposure and adverse event (AE) cluster terms of clinical concern was explored in this analysis. The incidence and severity of dysgeusia, muscle spasms, renal toxicity, and QT interval prolonged was modeled using ordinal logistic regression. AEs were graded using the National Cancer Institute Common Terminology Criteria for Adverse Events (version 4.03). Estimated pharmacokinetic parameters were used to derive glasdegib exposure metrics. Demographic characteristics, disease factors, and other variables of interest as potential moderators of safety signals were evaluated. Clinical trial data from patients who received single‐agent glasdegib (N = 70; 5–640 mg once daily); or glasdegib (N = 202, 100–200 mg once daily) with low‐dose cytarabine, decitabine, or daunorubicin and cytarabine were analyzed. Glasdegib exposure was statistically significantly associated with the cluster term safety end points dysgeusia, muscle spasms, renal toxicity, and QT interval prolonged. The impact of age on muscle spasms and baseline body weight and creatinine clearance on renal toxicity helped explain the AE grade distribution. At the 100 mg once daily clinical dose, the predicted probabilities of the highest AE grade were 11.3%, 6.7%, 7.7%, and 2.5% for dysgeusia, muscle spasms, renal toxicity, and QT interval prolonged, respectively. Overall, the predicted probability of developing an AE of any severity for these safety end points was low. Therefore, no starting dose adjustments are recommended for glasdegib based on the observed safety profile. [ABSTRACT FROM AUTHOR]

Glasdegib is an inhibitor of the Hedgehog pathway recently approved in the United States for the treatment of acute myeloid leukemia. A population pharmacokinetic analysis was conducted to characterize the kinetic behavior of glasdegib and its sources of variability (covariates) by utilizing data from 269 patients with cancer treated with oral glasdegib doses ranging from 5 to 640 mg/d. Nonlinear mixed-effects modeling was conducted using NONMEM (v.7.3) and Perl-speaks NONMEM (v.4.2.0). The estimated apparent total clearance, apparent central volume of distribution, and apparent peripheral volume of distribution were 6.27 L/h, 3.32 L, and 279.2 L, respectively. Age, sex, race, and hepatic function were not significant covariates on glasdegib pharmacokinetic parameters. Baseline body weight, percentage bone marrow blasts, creatinine clearance, and use of moderate or strong cytochrome P450 3A inhibitors were statistically significant covariates on apparent total clearance; however, the magnitude of the effects was not considered clinically meaningful., (© 2019 Pfizer Inc. The Journal of Clinical Pharmacology published by Wiley Periodicals, Inc. on behalf of American College of Clinical Pharmacology.)