Ascending single-dose study of the safety profile, tolerability, and pharmacokinetics of bosutinib coadministered with ketoconazole to healthy adult subjects

In Vitro Assessment of Inhibitory Effects of Kinase Inhibitors on CYP2C9, 3A and 1A2: Prediction of Drug-Drug Interaction Risk with Warfarin and Direct Oral Anticoagulants

OBJECTIVE

This study aimed to evaluate the cytochrome P450 (CYP)-mediated drug-drug interaction (DDI) potential of kinase inhibitors with warfarin and direct oral anticoagulants (DOACs).

METHODS

An in vitro CYP probe substrate cocktail assay was used to study the inhibitory effects of fifteen kinase inhibitors on CYP2C9, 3A, and 1A2. Then, DDI predictions were performed using both mechanistic static and physiologically-based pharmacokinetic (PBPK) models.

RESULTS

Linsitinib, masitinib, regorafenib, tozasertib, trametinib, and vatalanib were identified as competitive CYP2C9 inhibitors (Ki = 1.4, 1.0, 1.1, 3.8, 0.5, and 0.1 μM, respectively). Masitinib and vatalanib were competitive CYP3A inhibitors (Ki = 1.3 and 0.2 μM), and vatalanib noncompetitively inhibited CYP1A2 (Ki = 2.0 μM). Moreover, linsitinib and tozasertib were CYP3A time-dependent inhibitors (KI = 26.5 and 400.3 μM, kinact = 0.060 and 0.026 min-1, respectively). Only linsitinib showed time-dependent inhibition of CYP1A2 (KI = 13.9 μM, kinact = 0.018 min-1). Mechanistic static models identified possible DDI risks for linsitinib and vatalanib with (S)-/(R)-warfarin, and for masitinib with (S)-warfarin. PBPK simulations further confirmed that vatalanib may increase (S)- and (R)-warfarin exposure by 4.37- and 1.80-fold, respectively, and that linsitinib may increase (R)-warfarin exposure by 3.10-fold. Mechanistic static models predicted a smaller risk of DDIs between kinase inhibitors and apixaban or rivaroxaban. The greatest AUC increases (1.50-1.74) were predicted for erlotinib in combination with apixaban and rivaroxaban. Linsitinib, masitinib, and vatalanib were predicted to have a smaller effect on apixaban and rivaroxaban AUCs (AUCR 1.22-1.53). No kinase inhibitor was predicted to increase edoxaban exposure.

CONCLUSIONS

Our results suggest that several kinase inhibitors, including vatalanib and linsitinib, can cause CYP-mediated drug-drug interactions with warfarin and, to a lesser extent, with apixaban and rivaroxaban. The work provides mechanistic insights into the risk of DDIs between kinase inhibitors and anticoagulants, which can be used to avoid preventable DDIs in the clinic.

Clinical pharmacokinetics and drug-drug interactions of tyrosine-kinase inhibitors in chronic myeloid leukemia: A clinical perspective

In the past decade, numerous tyrosine kinase inhibitors (TKIs) have been introduced in the treatment of chronic myeloid leukemia. Given the significant interpatient variability in TKIs pharmacokinetics, potential drug-drug interactions (DDIs) can greatly impact patient therapy. This review aims to discuss the pharmacokinetic characteristics of TKIs, specifically focusing on their absorption, distribution, metabolism, and excretion profiles. Additionally, it provides a comprehensive overview of the utilization of TKIs in special populations such as the elderly, children, and patients with liver or kidney dysfunction. We also highlight known or suspected DDIs between TKIs and other drugs, highlighting various clinically relevant interactions. Moreover, specific recommendations are provided to guide haemato-oncologists, oncologists, and clinical pharmacists in managing DDIs during TKI treatment in daily clinical practice.

Organophosphorus Pesticides as Modulating Substances of Inflammation through the Cholinergic Pathway

Organophosphorus pesticides (OPs) are widespread insecticides used for pest control in agricultural activities and the control of the vectors of human and animal diseases. However, OPs’ neurotoxic mechanism involves cholinergic components, which, beyond being involved in the transmission of neuronal signals, also influence the activity of cytokines and other pro-inflammatory molecules; thus, acute and chronic exposure to OPs may be related to the development of chronic degenerative pathologies and other inflammatory diseases. The present article reviews and discusses the experimental evidence linking inflammatory process with OP-induced cholinergic dysregulation, emphasizing the molecular mechanisms related to the role of cytokines and cellular alterations in humans and other animal models, and possible therapeutic targets to inhibit inflammation.

Inhibition and induction of CYP enzymes in humans: an update

The cytochrome P450 (CYP) enzyme family is the most important enzyme system catalyzing the phase 1 metabolism of pharmaceuticals and other xenobiotics such as herbal remedies and toxic compounds in the environment. The inhibition and induction of CYPs are major mechanisms causing pharmacokinetic drug–drug interactions. This review presents a comprehensive update on the inhibitors and inducers of the specific CYP enzymes in humans. The focus is on the more recent human in vitro and in vivo findings since the publication of our previous review on this topic in 2008. In addition to the general presentation of inhibitory drugs and inducers of human CYP enzymes by drugs, herbal remedies, and toxic compounds, an in-depth view on tyrosine-kinase inhibitors and antiretroviral HIV medications as victims and perpetrators of drug–drug interactions is provided as examples of the current trends in the field. Also, a concise overview of the mechanisms of CYP induction is presented to aid the understanding of the induction phenomena.

Reviewing the role of healthy volunteer studies in drug development

BACKGROUND

With the exception of genotoxic oncology drugs, first-in-human, Phase 1 clinical studies of investigational drugs have traditionally been conducted in healthy volunteers (HVs). The primary goal of these studies is to investigate the pharmacokinetics and pharmacodynamics of a novel drug candidate, determine appropriate dosing, and document safety and tolerability.

MAIN BODY

When tailored to specific study objectives, HV studies are beneficial to manufacturers and patients alike and can be applied to both non-oncology and oncology drug development. Enrollment of HVs not only increases study accrual rates for dose-escalation studies but also alleviates the ethical concern of enrolling patients with disease in a short-term study at subtherapeutic doses when other studies (e.g. Phase 2 or Phase 3 studies) may be more appropriate for the patient. The use of HVs in non-oncology Phase 1 clinical trials is relatively safe but nonetheless poses ethical challenges because of the potential risks to which HVs are exposed. In general, most adverse events associated with non-oncology drugs are mild in severity, and serious adverse events are rare, but examples of severe toxicity have been reported. The use of HVs in the clinical development of oncology drugs is more limited but is nonetheless useful for evaluating clinical pharmacology and establishing an appropriate starting dose for studies in cancer patients. During the development of oncology drugs, clinical pharmacology studies in HVs have been used to assess pharmacokinetics, drug metabolism, food effects, potential drug-drug interactions, effects of hepatic and renal impairment, and other pharmacologic parameters vital for clinical decision-making in oncology. Studies in HVs are also being used to evaluate biosimilars versus established anticancer biologic agents.

CONCLUSION

A thorough assessment of toxicity and pharmacology throughout the drug development process is critical to ensure the safety of HVs. With the appropriate safeguards, HVs will continue to play an important role in future drug development.

Practical management of toxicities associated with bosutinib in patients with Philadelphia chromosome-positive chronic myeloid leukemia

Bosutinib (SKI-606) is an oral, dual Src/Abl tyrosine kinase inhibitor (TKI) approved for treatment of patients with Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia (CML) that is resistant or intolerant to prior TKI therapy or for whom other TKIs are not appropriate choices. The objective of this review is to provide a longitudinal summary of toxicities that may arise during treatment with second-line or later bosutinib in patients with Ph+ chronic phase CML and to provide strategies for managing these toxicities. As bosutinib is not currently indicated for newly diagnosed CML, toxicities associated with first-line treatment are not reviewed. Recognition and optimal management of these toxicities can facilitate patient compliance and affect treatment outcomes.

Effects of ketoconazole on cyclophosphamide metabolism: evaluation of CYP3A4 inhibition effect using the in vitro and in vivo models

Cyclophosphamide (CP) is widely used in anticancer therapy regimens and 2-dechloroethylcyclophosphamide (DECP) is its side-chain dechloroethylated metabolite. N-dechloroethylation of CP mediated by the enzyme CYP3A4 yields nephrotoxic and neurotoxic chloroacetaldehyde (CAA) in equimolar amount to DECP. This study aimed to evaluate the inhibitory effect of ketoconazole (KTZ) on CP metabolism through in vitro and in vivo drug-drug interaction (DDI) research. Long-term treatment of KTZ induces hepatic injury; thus single doses of KTZ at low, middle, and high levels (10, 20, and 40 mg/kg) were investigated for pharmacokinetic DDI with CP. Our in vitro human liver microsome modeling approach suggested that KTZ inhibited CYP3A4 activity and then decreased DECP exposure. In addition, an UHPLC-MS/MS method for quantifying CP, DECP, and KTZ in rat plasma was developed and fully validated with a 4 min analysis coupled with a simple and reproducible one-step protein precipitation. A further in vivo pharmacokinetic study demonstrated that combination use of CP (10 mg/kg) and KTZ (10, 20, and 40 mg/kg) in rats caused a KTZ dose-dependent decrease in main parameters of DECP (C_max, T_max, and AUC_0-∞) and provided magnitude exposure of DECP (more than a 50% AUC decrease) as a consequence of CYP3A inhibition but had only a small effect on the CP plasma concentration. Our results suggested that combination usage of a CYP3A4 inhibitor like KTZ may decrease CAA exposure and thus intervene against CAA-induced adverse effects in CP clinical treatment.

Clinical Pharmacokinetics and Pharmacodynamics of Bosutinib

Chronic myeloid leukemia (CML) is a clonal myeloproliferative stem cell disorder. Bosutinib is an oral, once-daily SRC/ABL tyrosine kinase inhibitor with very potent inhibitory activity. Bosutinib is effective against all phases of intolerant or resistant Philadelphia chromosome-positive CML that do not harbor the T315I or V299LABL kinase domain mutations. Peak plasma concentrations of bosutinib occur at 4-6 h following oral administration, and dose-proportional increases in exposure are observed at doses ranging from 200 to 800 mg. Absorption of bosutinib increases with food. Bosutinib is distributed extensively into the tissues. It is highly plasma protein bound (94 %) and is primarily metabolized in the liver by cytochrome P450 3A4. Bosutinib is well tolerated overall and has a unique but manageable toxicity profile. This article provides a review of the available clinical pharmacokinetic, pharmacodynamic, and drug-drug interaction data on bosutinib in healthy subjects, patients with CML, and special populations.

Clinical Drug-Drug Interactions Through Cytochrome P450 3A (CYP3A) for the Selective ALK Inhibitor Alectinib

The efficacy and safety of alectinib, a central nervous system-active and selective anaplastic lymphoma kinase (ALK) inhibitor, has been demonstrated in patients with ALK-positive (ALK+) non-small cell lung cancer (NSCLC) progressing on crizotinib. Alectinib is mainly metabolized by cytochrome P450 3A (CYP3A) to a major similarly active metabolite, M4. Alectinib and M4 show evidence of weak time-dependent inhibition and small induction of CYP3A in vitro. We present results from 3 fixed-sequence studies evaluating drug-drug interactions for alectinib through CYP3A. Studies NP28990 and NP29042 enrolled 17 and 24 healthy subjects, respectively, and investigated potent CYP3A inhibition with posaconazole and potent CYP3A induction through rifampin, respectively, on the single oral dose pharmacokinetics (PK) of alectinib. A substudy of the global phase 2 NP28673 study enrolled 15 patients with ALK+ NSCLC to determine the effect of multiple doses of alectinib on the single oral dose PK of midazolam, a sensitive substrate of CYP3A. Potent CYP3A inhibition or induction resulted in only minor effects on the combined exposure of alectinib and M4. Multiple doses of alectinib did not influence midazolam exposure. These results suggest that dose adjustments may not be needed when alectinib is coadministered with CYP3A inhibitors or inducers or for coadministered CYP3A substrates.

Effect of rifampin on the pharmacokinetics of bosutinib, a dual Src/Abl tyrosine kinase inhibitor, when administered concomitantly to healthy subjects

BACKGROUND

Bosutinib is an orally bioavailable dual Src/Abl tyrosine kinase inhibitor and a CYP3A4 enzyme substrate. This study assessed the safety, tolerability, and pharmacokinetics of bosutinib when coadministered with the CYP3A4 inducer rifampin in 24 healthy men.

METHODS

Subjects received single oral doses of bosutinib 500 mg (Days 1 and 14) and once-daily oral doses of rifampin 600 mg (Days 8-17); serial blood samples were analyzed.

RESULTS

Bosutinib exposures were reduced following concomitant administration of rifampin vs. bosutinib alone, measured by peak plasma concentration (C(max); 112 vs. 16.0 ng/mL; 86% reduction), total area under the concentration-time curve (AUC; 2740 vs. 207 ng·h/mL; 92% reduction), and AUC to the last measurable concentration at time T (2440 vs. 158 ng·h/mL; 94% reduction). Median time to C(max) and mean half-life were shorter for bosutinib plus rifampin vs. single-agent bosutinib. Oral clearance increased approximately 13-fold; the volume of distribution increased from 9560 to 72,900 L. Treatment-emergent adverse events appeared less frequently with bosutinib plus rifampin (59%) vs. single-agent bosutinib (79%); diarrhea was reported in 11 (46%) vs. 4 (18%) subjects, respectively.

CONCLUSIONS

Concomitant use of potent or moderate CYP3A inducers with bosutinib should be avoided because of the effects of drug-drug interaction observed between bosutinib and rifampin.

Population pharmacokinetic and pharmacodynamic analysis of bosutinib

Bosutinib is an orally active, competitive inhibitor of Src/Abl tyrosine kinases. A population pharmacokinetic model was developed using data pooled from 3 studies of patients (n = 870) with solid tumors or Philadelphia chromosome-positive leukemia. Patients (aged 18-91 y, weighing 35-221 kg) who received bosutinib 50 to 600 mg orally with food each contributed 6-9 pharmacokinetic samples. The final pharmacokinetic model was a linear two-compartment model with first-order absorption, an absorption lag-time, and dose-dependent bioavailability. Oral absorption was relatively slow, with a half-time of 1.14 h and a lag-time of 0.87 h; time to peak concentration was 5-6 h. Apparent clearance was 120 L/h. The apparent volume of the peripheral compartment was large with a slow turnover; alpha and beta half-lives were 19 h and 290 days, respectively. All parameters were estimated with acceptable precision (standard error <30%). No tested covariate (protocol, baseline demographic/clinical characteristics, or laboratory results) explained the high inter-individual variability of bosutinib pharmacokinetics. Therefore, adjusting bosutinib dose for body size (weight, surface area) would not provide benefit over fixed dosing. Using this exposure model in pharmacodynamic assessment of one study, adverse event incidence was shown to be similar in overall and bosutinib-responsive populations.