Effect of Carbamazepine on the Pharmacokinetics of Erdafitinib in Healthy Participants.

Erdafitinib, a selective and potent oral pan-FGFR inhibitor, is metabolized mainly through CYP2C9 and CYP3A4 enzymes. This phase 1, open-label, single-sequence, drug-drug interaction study evaluated the pharmacokinetics, safety, and tolerability of a single oral dose of erdafitinib alone and when co-administered with steady state oral carbamazepine, a dual inducer of CYP3A4 and CYP2C9, in 13 healthy adult participants (NCT04330248). Compared with erdafitinib administration alone, carbamazepine co-administration decreased total and free maximum plasma concentrations of erdafitinib (Cmax) by 35% (95% CI 30%-39%) and 22% (95% CI 17%-27%), respectively. The areas under the concentration-time curve over the time interval from 0 to 168 hours, to the last quantifiable data point, and to time infinity (AUC168h, AUClast, AUCinf), were markedly decreased for both total erdafitinib (56%-62%) and free erdafitinib (48%-55%). The safety profile of erdafitinib was consistent with previous clinical studies in healthy participants, with no new safety concerns when administered with or without carbamazepine. Co-administration with carbamazepine may reduce the activity of erdafitinib due to reduced exposure. Concomitant use of strong CYP3A4 inducers with erdafitinib should be avoided.

Demonstrating Bioequivalence for Two Dose Strengths of Niraparib and Abiraterone Acetate Dual-Action Tablets Versus Single Agents: Utility of Clinical Study Data Supplemented with Modeling and Simulation.

BACKGROUND AND OBJECTIVE: The combination of niraparib and abiraterone acetate (AA) plus prednisone is under investigation for the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC) and metastatic castration-sensitive prostate cancer (mCSPC). Regular-strength (RS) and lower-strength (LS) dual-action tablets (DATs), comprising niraparib 100 mg/AA 500 mg and niraparib 50 mg/AA 500 mg, respectively, were developed to reduce pill burden and improve patient experience. A bioequivalence (BE)/bioavailability (BA) study was conducted under modified fasting conditions in patients with mCRPC to support approval of the DATs. METHODS: This open-label randomized BA/BE study (NCT04577833) was conducted at 14 sites in the USA and Europe. The study had a sequential design, including a 21-day screening phase, a pharmacokinetic (PK) assessment phase comprising three periods [namely (1) single-dose with up to 1-week run-in, (2) daily dose on days 1-11, and (3) daily dose on days 12-22], an extension where both niraparib and AA as single-agent combination (SAC; reference) or AA alone was continued from day 23 until discontinuation, and a 30-day follow-up phase. Patients were randomly assigned in a parallel-group design (four-sequence randomization) to receive a single oral dose of niraparib 100 mg/AA 1000 mg as a LS-DAT or SAC in period 1, and patients continued as randomized into a two-way crossover design during periods 2 and 3 where they received niraparib 200 mg/AA 1000 mg once daily as a RS-DAT or SAC. The design was powered on the basis of crossover assessment of RS-DAT versus SAC. During repeated dosing (periods 2 and 3, and extension phase), all patients also received prednisone/prednisolone 5 mg twice daily. Plasma samples were collected for measurement of niraparib and abiraterone plasma concentrations. Statistical assessment of the RS-DAT and LS-DAT versus SAC was performed on log-transformed pharmacokinetic parameters data from periods 2 and 3 (crossover) and from period 1 (parallel), respectively. Additional paired analyses and model-based bioequivalence assessments were conducted to evaluate the similarity between the LS-DAT and SAC. RESULTS: For the RS-DAT versus SAC, the 90% confidence intervals (CI) of geometric mean ratios (GMR) for maximum concentration at a steady state (Cmax,ss) and area under the plasma concentration-time curve from 0-24 h at a steady state (AUC 0-24h,ss) were respectively 99.18-106.12% and 97.91-104.31% for niraparib and 87.59-106.69 and 86.91-100.23% for abiraterone. For the LS-DAT vs SAC, the 90% CI of GMR for AUC0-72h of niraparib was 80.31-101.12% in primary analysis, the 90% CI of GMR for Cmax,ss and AUC 0-24h,ss of abiraterone was 85.41-118.34% and 86.51-121.64% respectively, and 96.4% of simulated LS-DAT versus SAC BE trials met the BE criteria for both niraparib and abiraterone. CONCLUSIONS: The RS-DAT met BE criteria (range 80%-125%) versus SAC based on 90% CI of GMR for Cmax,ss and AUC 0-24h,ss. The LS-DAT was considered BE to SAC on the basis of the niraparib component meeting the BE criteria in the primary analysis for AUC 0-72h; abiraterone meeting the BE criteria in additional paired analyses based on Cmax,ss and AUC 0-24h,ss; and the percentage of simulated LS-DAT versus SAC BE trials meeting the BE criteria for both. GOV IDENTIFIER: NCT04577833.

A phase 1 study of intravenous mitazalimab, a CD40 agonistic monoclonal antibody, in patients with advanced solid tumors.

Mitazalimab is an agonistic human monoclonal antibody targeting CD40, a target for anti-tumor immunotherapy. This phase 1, dose-escalation study evaluated the safety, dose-limiting toxicities (DLTs), pharmacokinetic and pharmacodynamic profile of mitazalimab. Adults with advanced solid malignancies received mitazalimab intravenously once every-2-weeks. Dose-escalation was pursued with and without pre-infusion corticosteroids for mitigation of infusion-related reactions (IRRs). In all, 95 patients were enrolled in 7 cohorts (n = 50, 75-2000 µg/kg) with corticosteroids and in 5 cohorts (n = 45, 75-1200 µg/kg) without corticosteroids. Two patients experienced DLTs (transient Grade-3 headache; Grade-3 drug-induced liver injury [Hy's law]). The most frequently reported (≥ 25%) treatment-emergent adverse events were fatigue (44.2%), pyrexia (38.9%), pruritus (38.9%), chills (27.4%), and headache (26.3%). IRRs were reported in 51.6% of patients; pruritus (30.5%; with corticosteroids [36.0%], without corticosteroids [24.4%]) was the most frequent. Following the first infusions of 600 µg/kg and 2000 µg/kg, mitazalimab was rapidly cleared from the systemic circulation with mean terminal half-life of 11.9 and 24.1 h, respectively. Pharmacokinetics appeared to exhibit target-mediated drug disposition at the tested doses. Mitazalimab treatment induced higher levels of selected chemokines and transient reduction of B-cells, T-cells, and NK cells. One patient (renal cell carcinoma) displayed partial response lasting 5.6 months. Stable disease was reported by 35 (36.8%) patients, persisting for ≥ 6 months in 9 patients. Mitazalimab has a manageable safety profile with acceptable pharmacokinetic and pharmacodynamic properties. Future clinical development will evaluate combination with existing treatment options. Trial registration NCT02829099 (ClinicalTrials.gov; July 7, 2016).

Subcutaneous daratumumab in patients with relapsed or refractory multiple myeloma: Part 2 of the open-label, multicenter, dose-escalation phase 1b study (PAVO).

Intravenous daratumumab is approved for the treatment of multiple myeloma. In Part 1 of the PAVO study, a mix-and-deliver subcutaneous formulation of daratumumab with recombinant human hyaluronidase PH20 (rHuPH20) was well tolerated, with low rates of infusion-related reactions and similar efficacy to intravenous daratumumab. Part 2 of PAVO evaluated a concentrated, pre-mixed co-formulation of daratumumab and rHuPH20 (DARA SC). Patients with ≥2 prior lines of therapy, including a proteasome inhibitor and immunomodulatory drug, received daratumumab (1800 mg) and rHuPH20 (30,000 U) in 15 mL subcutaneously over 3-5 minutes per the approved intravenous monotherapy dosing schedule. Primary endpoints were daratumumab trough concentration at the end of weekly dosing (just prior to the Cycle 3 Day 1 dose) and safety. Twenty-five patients were enrolled in PAVO Part 2. DARA SC achieved daratumumab trough concentrations similar to or greater than intravenous daratumumab 16 mg/kg. The adverse event profile of DARA SC was consistent with intravenous daratumumab, with no new safety concerns and a lower infusion-related reaction rate. At a median follow-up of 14.2 months, the overall response rate was 52%, median duration of response was 15.7 months, and median progression-free survival was 12.0 months. DARA SC 1800 mg was well tolerated in relapsed/refractory multiple myeloma, with a low infusion-related reaction rate and reduced administration time. Daratumumab serum concentrations following DARA SC were consistent with intravenous dosing, and deep and durable responses were observed. Based on these results, ongoing studies are investigating DARA SC in multiple myeloma and other conditions. (ClinicalTrials.gov identifier: 02519452).

Ibrutinib does not have clinically relevant interactions with oral contraceptives or substrates of CYP3A and CYP2B6.

Ibrutinib may inhibit intestinal CYP3A4 and induce CYP2B6 and/or CYP3A. Secondary to potential induction, ibrutinib may reduce the exposure and effectiveness of oral contraceptives (OCs). This phase I study evaluated the effect of ibrutinib on the pharmacokinetics of the CYP2B6 substrate bupropion, CYP3A substrate midazolam, and OCs ethinylestradiol (EE) and levonorgestrel (LN). Female patients (N = 22) with B-cell malignancies received single doses of EE/LN (30/150 µg) and bupropion/midazolam (75/2 mg) during a pretreatment phase on days 1 and 3, respectively (before starting ibrutinib on day 8), and again after ibrutinib 560 mg/day for ≥ 2 weeks. Intestinal CYP3A inhibition was assessed on day 8 (single-dose ibrutinib plus single-dose midazolam). Systemic induction was assessed at steady-state on days 22 (EE/LN plus ibrutinib) and 24 (bupropion/midazolam plus ibrutinib). The geometric mean ratios (GMRs; test/reference) for maximum plasma concentration (Cmax ) and area under the plasma concentration-time curve (AUC) were derived using linear mixed-effects models (90% confidence interval within 80%-125% indicated no interaction). On day 8, the GMR for midazolam exposure with ibrutinib coadministration was ≤ 20% lower than the reference, indicating lack of intestinal CYP3A4 inhibition. At ibrutinib steady-state, the Cmax and AUC of EE were 33% higher than the reference, which was not considered clinically relevant. No substantial changes were noted for LN, midazolam, or bupropion. No unexpected safety findings were observed. A single dose of ibrutinib did not inhibit intestinal CYP3A4, and repeated administration did not induce CYP3A4/2B6, as assessed using EE, LN, midazolam, and bupropion.

Pharmacokinetics, Safety, and Antitumor Effect of Apalutamide with Abiraterone Acetate plus Prednisone in Metastatic Castration-Resistant Prostate Cancer: Phase Ib Study.

PURPOSE: Apalutamide is a next-generation androgen receptor (AR) inhibitor approved for patients with nonmetastatic castration-resistant prostate cancer (CRPC) and metastatic castration-sensitive prostate cancer. We evaluated the pharmacokinetics, safety, and antitumor activity of apalutamide combined with abiraterone acetate plus prednisone (AA-P) in patients with metastatic CRPC (mCRPC). PATIENTS AND METHODS: Multicenter, open-label, phase Ib drug-drug interaction study conducted in 57 patients with mCRPC treated with 1,000 mg abiraterone acetate plus 10 mg prednisone daily beginning on cycle 1 day 1 (C1D1) and 240 mg apalutamide daily starting on C1D8 in 28-day cycles. Serial blood samples for pharmacokinetic analysis were collected on C1D7 and C2D8. RESULTS: Systemic exposure to abiraterone, prednisone, and prednisolone decreased 14%, 61%, and 42%, respectively, when apalutamide was coadministered with AA-P. No increase in mineralocorticoid excess-related adverse events was observed. Patients without prior exposure to AR signaling inhibitors had longer median treatment duration and greater mean decrease in prostate-specific antigen (PSA) from baseline compared with those who had received prior therapy. Confirmed PSA reductions of ≥50% from baseline at any time were observed in 80% (12/15) of AR signaling inhibitor-naïve patients and 14% (6/42) of AR signaling inhibitor-treated patients. CONCLUSIONS: Treatment with apalutamide plus AA-P was well tolerated and showed evidence of antitumor activity in patients with mCRPC, including those with disease progression on AR signaling inhibitors. No clinically significant pharmacokinetic interaction was observed between abiraterone and apalutamide; however, apalutamide decreased exposure to prednisone. These data support development of 1,000 mg abiraterone acetate plus 10 mg prednisone daily with 240 mg apalutamide daily in patients with mCRPC.

Pharmacokinetic Drug-Drug Interaction of Apalutamide, Part 1: Clinical Studies in Healthy Men and Patients with Castration-Resistant Prostate Cancer.

BACKGROUND AND OBJECTIVES: Two phase I studies assessed the drug-drug interaction potential of apalutamide as a substrate and perpetrator. METHODS: Study A randomized 45 healthy men to single-dose apalutamide 240 mg alone or with strong inhibitors of cytochrome P450 (CYP)3A4 (itraconazole) or CYP2C8 (gemfibrozil). In study B, 23 patients with castration-resistant prostate cancer received probes for CYP3A4 (midazolam), CYP2C9 (warfarin), CYP2C19 (omeprazole), and CYP2C8 (pioglitazone), and transporter substrates for P-glycoprotein (P-gp) (fexofenadine) and breast cancer resistance protein (BCRP)/organic anion transporting polypeptide (OATP) 1B1 (rosuvastatin) at baseline and after repeat once-daily administration of apalutamide 240 mg to steady state. RESULTS: Systemic exposure (area under the plasma concentration-time curve) to single-dose apalutamide increased 68% with gemfibrozil but was relatively unchanged with itraconazole (study A). Apalutamide reduced systemic exposure to midazolam ↓92%, omeprazole ↓85%, S-warfarin ↓46%, fexofenadine ↓30%, rosuvastatin ↓41%, and pioglitazone ↓18% (study B). After a single dose, apalutamide is predominantly metabolized by CYP2C8, and less by CYP3A4. CONCLUSIONS: Co-administration of apalutamide with CYP3A4, CYP2C19, CYP2C9, P-gp, BCRP or OATP1B1 substrates may cause loss of activity for these medications. Therefore, appropriate mitigation strategies are recommended.

Effect of Fluconazole and Itraconazole on the Pharmacokinetics of Erdafitinib in Healthy Adults: A Randomized, Open-Label, Drug-Drug Interaction Study.

BACKGROUND AND OBJECTIVES: Erdafitinib, an oral selective pan-fibroblast growth factor receptor (FGFR) kinase inhibitor, is primarily metabolized by cytochrome P450 (CYP) 2C9 and 3A4. The aim of this phase 1 study was to assess the pharmacokinetics and safety of erdafitinib in healthy participants when coadministered with fluconazole (moderate CYP2C9 and CYP3A inhibitor), and itraconazole (a strong CYP3A4 and P-glycoprotein inhibitor). The effect of CYP2C9 genotype variants (*1/*1, *1/*2, *1/*3) on the pharmacokinetics of erdafitinib was also investigated. METHODS: In this open-label, parallel-group, single-center study, eligible healthy adults were randomized by CYP2C9 genotype to receive Treatment A (single oral dose of erdafitinib 4 mg) on day 1, Treatment B (fluconazole 400 mg/day orally) on days 1-11, or Treatment C (itraconazole 200 mg/day orally) on days 1-11. Healthy adults randomized to Treatment B and C received a single oral 4-mg dose of erdafitinib on day 5. The pharmacokinetic parameters, including mean maximum plasma concentration (Cmax), area under the curve (AUC) from time 0 to 168 h (AUC168h), AUC from time 0 to the last quantifiable concentration (AUClast), and AUC from time 0 to infinity (AUC∞) were calculated from individual plasma concentration-time data using standard non-compartmental methods. RESULTS: Coadministration of erdafitinib with fluconazole increased Cmax of erdafitinib by approximately 21%, AUC168h by 38%, AUClast by 49%, and AUC∞ by 48% while coadministration with itraconazole resulted in no change in erdafitinib Cmax and increased AUC168h by 20%, AUClast by 33% and AUC∞ by 34%. Erdafitinib exposure was comparable between participants with CYP2C9 *1/*2 or *1/*3 and with wild-type CYP2C9 genotype. The ratio of total amount of erdafitinib excreted in the urine (inhibited to non-inhibited) was 1.09, the ratio of total amount of excreted metabolite M6 was 1.21, and the ratio of the metabolite to parent ratio in the urine was 1.11, when coadministration of erdafitinib with itraconazole was compared with single-dose erdafitinib. Treatment-emergent adverse events (TEAEs) were generally Grade 1 or 2 in severity; the most commonly reported TEAE was headache. No safety concerns were identified with single-dose erdafitinib when administered alone and in combination with fluconazole or itraconazole in healthy adults. CONCLUSION: Coadministration of fluconazole or itraconazole or other moderate/strong CYP2C9 or CYP3A4 inhibitors may increase exposure to erdafitinib in healthy adults and thus may warrant erdafitinib dose reduction or use of alternative concomitant medications with no or minimal CYP2C9 or CYP3A4 inhibition potential. TRIAL REGISTRATION: ClinicalTrials.gov identifier number: NCT03135106.

Subcutaneous delivery of daratumumab in relapsed or refractory multiple myeloma.

Daratumumab, a human monoclonal antibody targeting CD38, is approved as monotherapy and in combination regimens for patients with multiple myeloma (MM). Currently, daratumumab is administered IV. The phase 1b PAVO (MMY1004) study evaluated subcutaneously administered daratumumab in combination with the recombinant human hyaluronidase PH20 enzyme (rHuPH20) in patients with relapsed or refractory MM. Part 1 of the study, reported here, evaluated a mix-and-deliver (MD) formulation of daratumumab and rHuPH20 (DARA-MD) administered by subcutaneous infusion. Patients received subcutaneous daratumumab according to the approved IV monotherapy dosing schedule at 1200 mg (n = 8) or 1800 mg (n = 45). Primary end points were safety and pharmacokinetic (PK) variables. The most common treatment-emergent adverse events with DARA-MD 1200 mg were thrombocytopenia, upper respiratory tract infection, insomnia, and decreased appetite (37.5% each). Anemia (33.3%), upper respiratory tract infection, pyrexia, and diarrhea (26.7% each) were the most common treatment-emergent adverse events with DARA-MD 1800 mg. One patient in the 1200-mg dose group (12.5%) and 11 patients in the 1800-mg dose group (24.4%) experienced infusion-related reactions, which were generally grade 1/2 and typically occurred at the first infusion. The 1800 mg dose achieved similar or greater serum concentrations compared with the 16 mg/kg IV dose. Overall response rates of 25.0% and 42.2% were achieved with 1200-mg and 1800-mg DARA-MD, respectively. Subcutaneous administration of DARA-MD was well tolerated in patients with relapsed or refractory MM, with the 1800-mg dose exhibiting PK concentrations and responses consistent with IV daratumumab in a similar patient population. This study was registered at www.clinicaltrials.gov as #NCT02519452.

An open-label, multicenter, phase Ib study investigating the effect of apalutamide on ventricular repolarization in men with castration-resistant prostate cancer.

PURPOSE: Phase Ib study evaluating the effect of apalutamide, at therapeutic exposure, on ventricular repolarization by applying time-matched pharmacokinetics and electrocardiography (ECG) in patients with castration-resistant prostate cancer. Safety of daily apalutamide was also assessed. METHODS: Patients received 240 mg oral apalutamide daily. Time-matched ECGs were collected via continuous 12-lead Holter recording before apalutamide (Day - 1) and on Days 1 and 57 (Cycle 3 Day 1). Pharmacokinetics of apalutamide were assessed on Days 1 and 57 at matched time points of ECG collection. QT interval was corrected for heart rate using Fridericia correction (QTcF). The primary endpoint was the maximum mean change in QTcF (ΔQTcF) from baseline to Cycle 3 Day 1 (steady state). Secondary endpoints were the effect of apalutamide on other ECG parameters, pharmacokinetics of apalutamide and its active metabolite, relationship between plasma concentrations of apalutamide and QTcF, and safety. RESULTS: Forty-five men were enrolled; 82% received treatment for ≥ 3 months. At steady state, the maximum ΔQTcF was 12.4 ms and the upper bound of its associated 90% CI was 16.0 ms. No clinically meaningful effects of apalutamide were reported for heart rate or other ECG parameters. A concentration-dependent increase in QTcF was observed for apalutamide. Most adverse events (AEs) (73%) were grade 1-2 in severity. No patients discontinued due to QTc prolongation or AEs. CONCLUSION: The effect of apalutamide on QTc prolongation was modest and does not produce a clinically meaningful effect on ventricular repolarization. The AE profile was consistent with other studies of apalutamide.

The pH-altering agent omeprazole affects rate but not the extent of ibrutinib exposure.

PURPOSE: This drug-interaction study evaluated the effect of omeprazole, a proton-pump inhibitor, on ibrutinib's pharmacokinetics (PK) in healthy participants. METHODS: This open-label, sequential-design study included 20 healthy adults aged 18-55 years. Ibrutinib (560 mg, single dose) was administered after an overnight fast alone on day 1 and with omeprazole on day 7. Omeprazole (40 mg) alone was administered on days 3-6, 1 h before breakfast; and after an overnight fast on day 7, followed by ibrutinib 2 h later. Blood was sampled on days 1 and 7 for up to 48 h postdose, and the standard PK parameters for ibrutinib and PCI-45227 were summarized using descriptive statistics. The effect of omeprazole on ibrutinib's PK was determined by assessing geometric mean ratios (GMRs) and 90% CIs. Mechanistic modeling was performed using the BTK-receptor occupancy (RO) model. RESULTS: AUC48h and AUClast of ibrutinib plus omeprazole versus ibrutinib alone showed a modest decrease (GMR [90% CI] 98.3% [83.1-116.3] and 92.5% [77.8-109.9], respectively); Cmax decreased by 62.5% (GMR [90% CI] 37.5% [26.4-53.4]), with delayed tmax (1-2 h) and terminal half-life unaffected. Mean AUC for PCI-45227 (primary metabolite) was ~ 20% lower with ibrutinib plus omeprazole versus ibrutinib alone. Model predictions showed no impact of decreased Cmax on BTK target engagement. No new safety signals were identified with the use of ibrutinib in this study. CONCLUSIONS: The decrease in Cmax without a corresponding decrease in AUC by omeprazole was not clinically relevant for ibrutinib's bioavailability. No dose adjustments are recommended during ibrutinib's co-administration with omeprazole or other pH-altering agents.

A drug-drug interaction study of ibrutinib with moderate/strong CYP3A inhibitors in patients with B-cell malignancies.

This was an open-label, multicenter, phase-1 study to evaluate the drug interaction between steady-state ibrutinib and moderate (erythromycin) and strong (voriconazole) CYP3A inhibitors in patients with B-cell malignancies and to confirm dosing recommendations. During cycle 1, patients received oral ibrutinib 560 mg qd alone (Days 1-4 and 14-18), and ibrutinib 140 mg (Days 5-13; 19-27) plus erythromycin 500 mg tid (Days 5-11) and voriconazole 200 mg bid (Days 19-25). Twenty-six patients (median [range] age: 64.5 [50-88] years) were enrolled. Geometric mean ratio (90% confidence intervals) after co-administration of ibrutinib 140 mg with erythromycin and voriconazole was 74.7 (53.97-103.51) and 143.3 (107.77-190.42), respectively, versus ibrutinib 560 mg alone. The most common (≥20%) adverse events were diarrhea (27%) and neutropenia (23%). The results demonstrate that ibrutinib 140 mg with voriconazole or erythromycin provides exposure within the clinical range for patients with B-cell malignancies.

Correction to: Ibrutinib does not prolong the corrected QT interval in healthy subjects: results from a thorough QT study.

The author would like to correct the affiliations and conflict of interest in the publication of the original article. The corrected details are given below for your reading.

Ibrutinib does not prolong the corrected QT interval in healthy subjects: results from a thorough QT study.

PURPOSE: Ibrutinib is an orally administered, irreversible Bruton's tyrosine kinase inhibitor for treatment of B-cell malignancy. This study evaluated the effects of single-dose ibrutinib at therapeutic and supratherapeutic exposures on cardiac repolarization in healthy subjects. METHODS: Part 1 used an open-label, two-period sequential design to assess the safety and pharmacokinetics of single doses of ibrutinib 840 and 1680 mg in eight subjects. Part 2 was a randomized, placebo- and positive (moxifloxacin)-controlled, double-blind, single dose, four-way cross-over study to assess the effect of ibrutinib (840 and 1680 mg) on QT/QTc interval. 64 healthy subjects were planned to be enrolled. Baseline-adjusted QT (QTc) intervals for ibrutinib and moxifloxacin (assay sensitivity) were compared to placebo using linear mixed-effect model. A concentration-QTc analysis was also conducted. RESULTS: No clinically relevant safety observations were noted in Part 1. During Part 2, one subject experienced Grade 4 ALT/AST elevations with ibrutinib 1680 mg, leading to study termination and limiting the enrollment to 20 subjects. Ibrutinib demonstrated dose-dependent increases in exposure. The upper bounds of the 90% CIs for the mean difference in change from baseline in QTc between ibrutinib and placebo were < 10 ms at all timepoints and at supratherapeutic C max. Moxifloxacin showed the anticipated QTc effect, confirming assay sensitivity despite the early study termination. Ibrutinib caused a concentration-dependent mild shortening of QTc and mild PR prolongation, but these effects were not considered clinically meaningful. CONCLUSIONS: Therapeutic and supratherapeutic concentrations of ibrutinib do not prolong the QTc interval. CLINICALTRIALS.GOV: NCT02271438.

Single-dose pharmacokinetics of ibrutinib in subjects with varying degrees of hepatic impairment.

This open-label, single-dose study was designed to characterize pharmacokinetics and safety profile of ibrutinib in hepatically impaired subjects. Each subject received single oral dose of ibrutinib (140 mg) following an overnight fast (hepatic impairment-mild [n = 6], moderate [n = 10], and severe [n = 8]; healthy control [n = 6]). Subjects with hepatic impairment showed significant increase in ibrutinib plasma exposures and fraction unbound ibrutinib. Compared to control group, mean exposure (AUClast; unbound) in mild, moderate, and severe cohorts was 4.1-, 9.8-, 13.4-fold higher, respectively. Terminal half-life trended slightly longer in moderately and severely impaired subjects, but risk of accumulation on repeated dosing appears negligible as half-life did not exceed 10 h. Based on observed effects on exposure, reduced doses are recommended for patients with mild and moderate liver impairment (Child-Pugh Class A and B), whereas 140 mg is considered too high for severely impaired patients (Class-C). A single dose of 140 mg was well tolerated in this study (NCT01767948).

Quisinostat, bortezomib, and dexamethasone combination therapy for relapsed multiple myeloma.

The maximum tolerated dose (MTD) of quisinostat + bortezomib + dexamethasone in patients with relapsed multiple myeloma was evaluated in a phase-1b, open-label, multicenter, '3 + 3' dose-escalation study. Patients received escalating doses of oral quisinostat (6 mg [n = 3], 8 mg [n = 3], 10 mg [n = 6], and 12 mg [n = 6] on days 1, 3, and 5/week) plus subcutaneous bortezomib (1.3 mg/m(2)) and oral dexamethasone (20 mg) in cycles of 21 (cycles 1-8) or 35 d (cycles 9-11) until MTD was determined. No dose-limiting toxicities were reported in 6/8 mg groups except ventricular fibrillation (Grade 4 cardiac arrest, n = 1 [10 mg] cycle 6) and clinically significant cardiac toxicities (Grade 3 QTc prolongation, Grade 3 atrial fibrillation, n = 2 [12 mg]). Thrombocytopenia (n = 11), asthenia (n = 10), and diarrhea (n = 12) were most common adverse events. Overall, 88.2% patients achieved treatment response, median duration of response, and median progression-free survival were 9.4 and 8.2 months, respectively. The MTD of quisinostat was established as 10 mg thrice weekly oral dose with bortezomib + dexamethasone.

Stable isotope-labelled intravenous microdose for absolute bioavailability and effect of grapefruit juice on ibrutinib in healthy adults.

AIMS: Ibrutinib, an inhibitor of Bruton's tyrosine kinase, is used in the treatment of mantle cell lymphoma or chronic lymphocytic leukaemia. Ibrutinib undergoes extensive rapid oxidative metabolism mediated by cytochrome P450 3A both at the level of first pass and clearance, which might result in low oral bioavailability. The present study was designed to investigate the absolute bioavailability (F) of ibrutinib in the fasting and fed state and assess the effect of grapefruit juice (GFJ) on the systemic exposure of ibrutinib in order to determine the fraction escaping the gut (Fg ) and the fraction escaping hepatic extraction (Fh ) in the fed state. METHODS: All participants received treatment A [560 mg oral ibrutinib, under fasting conditions], B (560 mg PO ibrutinib, fed, administered after drinking glucose drink) and C (140 mg oral ibrutinib, fed, with intake of GFJ before dosing). A single intravenous (i.v.) dose of 100 µg (13) C6 -ibrutinib was administered 2 h after each oral dose. RESULTS: The estimated 'F' for treatments A, B and C was 3.9%, 8.4% and 15.9%, respectively. Fg and Fh in the fed state were 47.0% and 15.9%, respectively. Adverse events were mild to moderate in severity (Grade 1-2) and resolved without sequelae by the end of the study. CONCLUSION: The absolute oral bioavailability of ibrutinib was low, ranging from 3.9% in the fasting state to 8.4% when administered 30 min before a standard breakfast without GFJ and 15.9% with GFJ. Ibrutinib was well tolerated following a single oral and i.v. dose, under both fasted and fed conditions and regardless of GFJ intake status.

Effect of CYP3A perpetrators on ibrutinib exposure in healthy participants.

Ibrutinib (PCI-32765), a potent covalent inhibitor of Bruton's tyrosine kinase, has shown efficacy against a variety of B-cell malignancies. Given the prominent role of CYP3A in ibrutinib metabolism, effect of coadministration of CYP3A perpetrators with ibrutinib was evaluated in healthy adults. Ibrutinib (120 mg [Study 1, fasted], 560 mg [studies 2 (fasted), and 3 (nonfasted)]) was given alone and with ketoconazole [Study 1; 400 mg q.d.], rifampin [Study 2; 600 mg q.d.], and grapefruit juice [GFJ, Study 3]. Lower doses of ibrutinib were used together with CYP3A inhibitors [Study 1: 40 mg; Study 3: 140 mg], as safety precaution. Under fasted condition, ketoconazole increased ibrutinib dose-normalized (DN) exposure [DN-AUClast: 24-fold; DN-C max: 29-fold], rifampin decreased ibrutinib exposure [C max: 13-fold; AUClast: 10-fold]. Under nonfasted condition, GFJ caused a moderate increase [DN-C max: 3.5-fold; DN-AUC: 2.2-fold], most likely through inhibition of intestinal CYP3A. Half-life was not affected by CYP perpetrators indicating the interaction was mainly on first-pass extraction. All treatments were well-tolerated.

The effect of food on the pharmacokinetics of oral ibrutinib in healthy participants and patients with chronic lymphocytic leukemia.

PURPOSE: To assess ibrutinib pharmacokinetics under fasted and fed conditions, impact of food-intake timing, and the safety and tolerability. METHODS: Three studies were analyzed. Study 1 was a randomized, open-label, single-dose, four-way crossover study in 44 healthy participants. Study 2 was a randomized, repeat-dose crossover study in 16 patients with previously treated chronic lymphocytic leukemia (CLL). Ibrutinib dose was 420 mg in both studies. Study 3 was an open-label, sequential study to assess the effect of a standard breakfast on ibrutinib 560 mg in eight healthy participants. RESULTS: Administration of single-dose ibrutinib under fasting conditions (study 1) resulted in approximately 60 % of exposure compared with drug intake either 30 min before, 30 min after (fed), or 2 h after a high-fat meal. Similar food effect was observed (study 3) when ibrutinib was given 30 min before meal. In CLL patients (study 2), the C max and AUC under fasting conditions were 43 and 61 %, respectively, relative to fed conditions. When administered once-daily in uncontrolled food-intake conditions (≥30 min before or 2 h after), exposures were slightly (≈30 %) lower than in fed condition. When corrected for repeated dosing, pharmacokinetic parameters in healthy participants and patients were comparable. Ibrutinib was generally well tolerated in all settings studied. CONCLUSIONS: Ibrutinib administered in fasted condition reduces exposure to approximately 60 % as compared with dosing in proximity to food-intake, regardless of timing/type of meal. Because repeated drug intake in fasted condition is unlikely, no food restrictions may be needed to administer ibrutinib.