Evaluation of drug interaction potential of zanubrutinib with cocktail probes representative of CYP3A4, CYP2C9, CYP2C19, P-gp and BCRP.

AIM: This study aims to assess the potential effects of zanubrutinib on the activity of cytochrome P450 (CYP) enzymes and drug transporter proteins using a cocktail probe approach. METHODS: Patients received single oral doses of probe drugs alone and after at least 8 days of treatment with zanubrutinib 160 mg twice daily in a single-sequence study in 18 healthy male volunteers. Simultaneous doses of 10 mg warfarin (CYP2C9) and 2 mg midazolam (CYP3A) were administered on Day 1 and Day 14, 0.25 mg digoxin (P-glycoprotein [P-gp]) and 10 mg rosuvastatin (breast cancer resistance protein [BCRP]) on Day 3 and Day 16, and 20 mg omeprazole (CYP2C19) on Day 5 and Day 18. Pharmacokinetic (PK) parameters were estimated from samples obtained up to 12 h post dose for zanubrutinib; 24 h for digoxin, omeprazole and midazolam; 48 h for rosuvastatin; and 144 h for warfarin. RESULTS: The ratios (%) of geometric least squares means (90% confidence intervals) for the area under the concentration-time curve from time zero to the last quantifiable concentration in the presence/absence of zanubrutinib were 99.80% (97.41-102.2%) for S-warfarin; 52.52% (48.49-56.88%) for midazolam; 111.3% (103.8-119.3%) for digoxin; 89.45% (78.73-101.6%) for rosuvastatin; and 63.52% (57.40-70.30%) for omeprazole. Similar effects were observed for maximum plasma concentrations. CONCLUSIONS: Zanubrutinib 320 mg total daily dose had minimal or no effect on the activity of CYP2C9, BCRP and P-gp, but decreased the systemic exposure of CYP3A and CYP2C19 substrates (mean reduction <50%).

Phase I Study of Glesatinib (MGCD265) in Combination with Erlotinib or Docetaxel in Patients with Advanced Solid Tumors.

BACKGROUND: Oncogenic drivers in solid tumors include aberrant activation of mesenchymal epithelial transition factor (MET) and AXL. OBJECTIVE: This study investigated the safety and antitumor activity of glesatinib, a multitargeted receptor tyrosine kinase inhibitor that inhibits MET and AXL at clinically relevant doses, in combination with erlotinib or docetaxel. PATIENTS AND METHODS: The phase I portion of this open-label, multicenter study included two parallel arms in which ascending doses of oral glesatinib (starting dose 96 mg/m2) were administered with erlotinib or docetaxel (starting doses 100 mg once daily and 50 mg/m2, respectively) using a modified 3 + 3 design. Maximum tolerated dose (MTD) was based on dose-limiting toxicities (DLTs) during the first 21-day treatment cycle. Enrollment focused on patients with solid tumor types typically associated with MET aberration and/or AXL overexpression. The primary objective was to determine the safety profile of the treatment combinations. Antitumor activity and pharmacokinetics (PK) were also assessed. RESULTS: Ten dose levels of glesatinib across three glycolate formulations (unmicronized, micronized, or micronized version 2 [V2] tablets) available during the course of the study were investigated in 14 dose-escalation cohorts (n = 126). MTDs of unmicronized glesatinib plus erlotinib or docetaxel, and micronized glesatinib plus erlotinib were not reached. Micronized glesatinib 96 mg/m2 plus docetaxel exceeded the MTD. Further dosing focused on glesatinib micronized V2: maximum administered dose (MAD) was 700 mg twice daily with erlotinib 150 mg once daily or docetaxel 75 mg/m2 every 3 weeks. DLTs, acceptable at lower glesatinib (micronized V2) dose levels, occurred in two of five and two of six patients at the MADs of glesatinib + erlotinib and glesatinib + docetaxel, respectively. Across all cohorts, the most frequent treatment-related adverse events were diarrhea (glesatinib + erlotinib: 84.1%; glesatinib + docetaxel: 45.6%), fatigue (46.4%, 70.4%), and nausea (30.4%, 35.1%). The objective response rate was 1.8% and 12.0% in all glesatinib + erlotinib and glesatinib + docetaxel cohorts, respectively. CONCLUSIONS: The safety profile of glesatinib plus erlotinib or docetaxel was acceptable and there were no PK interactions. MADs of glesatinib 700 mg twice daily (micronized V2) with erlotinib 150 mg once daily or docetaxel 75 mg/m2 every 3 weeks exceeded the MTD by a small margin. Modest signals of efficacy were observed with these treatment combinations in non-genetically selected patients with advanced solid tumors. CLINICAL TRIALS REGISTRATION: ClinicalTrials.gov NCT00975767; 11 September 2009.

No QTc Prolongation With Zanubrutinib: Results of Concentration-QTc Analysis From a Thorough QT Study in Healthy Subjects.

This thorough QT (TQT) study evaluated the effect of zanubrutinib on electrocardiogram (ECG) parameters by using concentration-QTc (C-QTc) analysis as the primary analysis for this study. Part A of the study determined the safety and tolerability of a single supratherapeutic dose of zanubrutinib (480 mg) in healthy volunteers. Part B was a randomized, blinded, placebo-controlled and positive-controlled, four-way crossover, TQT study of single therapeutic (160 mg) and supratherapeutic (480 mg) doses of zanubrutinib, placebo, and open-label moxifloxacin 400 mg. Thirty-two participants received at least 1 dose of zanubrutinib, and 26 participants completed all 4 periods. Zanubrutinib did not have any effect on heart rate or cardiac conduction (pulse rate, QRS interval, or T-wave morphology) and was generally well-tolerated. Using C-QTc analysis, the predicted placebo-corrected change-from-baseline QT interval using Fridericia's formula (ΔΔQTcF) was -3.4 msec (90% confidence interval: -4.9 to -1.9 msec) at peak concentrations of the 480 mg dose. A QT effect (ΔΔQTcF) exceeding 10 msec could be excluded within the observed concentration range at 160 and 480 mg doses. Assay sensitivity was established by moxifloxacin with 90% lower bound exceeding 5 msec. Implementing a C-QTc analysis prospectively in this TQT study resulted in a substantially smaller sample size to maintain a similar study power as shown in the traditional time-point analysis. A single 160-mg or 480-mg zanubrutinib dose did not prolong the QTc interval or have any other clinically relevant effects on ECG parameters.

A phase 1, open-label, single-dose study of the pharmacokinetics of zanubrutinib in subjects with varying degrees of hepatic impairment.

The pharmacokinetics and safety of single-dose zanubrutinib (80 mg) were assessed in subjects with mild, moderate, and severe hepatic impairment (n = 6 each, Child-Pugh class A, B, and C) relative to healthy controls (n = 11). Zanubrutinib median Tmax was 1.25-2.25 h in all groups. Compared to control group, mean zanubrutinib exposure (AUC0-inf) in the mild and moderate hepatic impairment groups was increased by 1.1- and 1.2-fold, which is within the range of PK variability for zanubrutinib. The total and unbound AUC of zanubrutinib were 1.60- and 2.9-fold higher in subjects with severe hepatic impairment compared to healthy controls. Terminal half-life was comparable between subjects with hepatic impairment and matched healthy controls. Zanubrutinib was generally well-tolerated when administered as a single, 80-mg dose to subjects in this study. Results of this study will be used, in conjunction with clinical safety and efficacy data, to develop dose recommendations for patients with hepatic impairment.

Effect of rifampin and itraconazole on the pharmacokinetics of zanubrutinib (a Bruton's tyrosine kinase inhibitor) in Asian and non-Asian healthy subjects.

PURPOSE: Zanubrutinib (BGB-3111) is a potent Bruton's tyrosine kinase inhibitor with promising clinical activity in B-cell malignancies. Zanubrutinib was shown to be mainly metabolized through cytochrome P450 3A (CYP3A) in vitro. We evaluated the effect of steady-state rifampin (a strong CYP3A inducer) and steady-state itraconazole (a strong CYP3A inhibitor) on the pharmacokinetics (PK), safety, and tolerability of zanubrutinib in healthy Asian and non-Asian subjects. METHODS: In this open-label, two-part clinical study, 20 participants received a single oral dose of zanubrutinib (320 mg) and oral rifampin (600 mg) in Part A, and 18 participants received a single oral dose of zanubrutinib (20 mg) and oral itraconazole (200 mg) in Part B. Serial blood samples were collected after administration of zanubrutinib alone and zanubrutinib in combination with rifampin or itraconazole for the measurement of PK parameters. RESULTS: Coadministration with rifampin decreased AUC0-∞ of zanubrutinib by 13.5-fold and Cmax by 12.6-fold. Coadministration with itraconazole increased the AUC0-∞ of zanubrutinib by 3.8-fold and Cmax by 2.6-fold. The PK of zanubrutinib was consistent between Asian and non-Asian subjects, and  zanubrutinib was well tolerated in this study. CONCLUSIONS: These results confirm that zanubrutinib is primarily metabolized by CYP3A in humans. The PK of zanubrutinib was comparable between Asian and non-Asian subjects and, therefore, no dose modifications are necessary for zanubrutinib in these ethnic populations.