Effect of Efavirenz on the Pharmacokinetics of SHR6390 in Healthy Volunteers.

ABSTRACT

Purpose: SHR6390 is an oral, potent and selective small-molecule CDK4/6 inhibitor for the treatment of human breast, ovarian and colon cancer. Previous studies have shown that SHR6390 in combination with rifampicin, a potent inducer of CYP3A4, significantly reduces exposure levels. Therefore, we further investigated the effect of efavirenz, a moderate CYP3A4 inducer, on a single oral dose of SHR6390 in healthy volunteers. Patients and Methods: Twenty healthy subjects were enrolled in this single-center, open, single-dose, self-controlled DDI study. On Day 1, subjects received a single oral dose of 150mg SHR6390; on Day 8-26, subjects received 600 mg efavirenz orally at night, with a single dose of 150 mg SHR6390 on Day 22. Blood samples for pharmacokinetic analyses were collected. Results: The geometric mean ratios of the maximum concentration(Cmax) and the area under the concentration curve from zero to infinity (AUC0-inf) between combination therapy and SHR6390 monotherapy (combination therapy/SHR6390 monotherapy) and their 90% confidence intervals were 0.562 (0.482, 0.654) and 0.328 (0.278, 0.386), respectively. This indicates that the Cmax and AUC0 inf of SHR6390 decreased by approximately 43.8% and 67.2%, respectively. Oral administration of 150 mg SHR6390 alone or together with efavirenz was safe and tolerable in healthy subjects. Conclusion: It is suggested that under the action of the moderate CPY3A4 inducer efavirenz, the exposure AUC of SHR6390 exhibits a moderate level of induction. It is recommended to avoid concomitant administration of moderate inducers of CYP3A4 during treatment with SHR6390. Trial Registration http//www.chinadrugtrials.org.cn/index.html, CTR20211571/ https//classic.clinicaltrials.gov, NCT04973020.