The effect of itraconazole and rifampicin on the pharmacokinetics of osimertinib

Concomitant osimertinib and antituberculosis therapy in an elderly patient with EGFR-mutated lung cancer and pulmonary tuberculosis: A case report

The concurrent incidence of lung cancer and tuberculosis is expected to escalate due to the projected growth in the older population. Combination therapy with osimertinib and antituberculosis drugs has not been well-established. We report a case of successful treatment involving the concomitant administration of osimertinib and antituberculosis drugs in an older patient, an 89-year-old female, diagnosed with epidermal growth factor receptor (EGFR)-mutant lung cancer and pulmonary tuberculosis. Accumulating evidence is warranted to develop an optimal treatment strategy for patients with lung cancer and tuberculosis.

Exploring inter-ethnic and inter-patient variability and optimal dosing of osimertinib: a physiologically based pharmacokinetic modeling approach

Purpose: This study aimed to develop and validate a physiologically based pharmacokinetic (PBPK) model for osimertinib (OSI) to predict plasma trough concentration (Ctrough) and pulmonary EGFRm+ (T790M and L858R mutants) inhibition in Caucasian, Japanese, and Chinese populations. The PBPK model was also utilized to investigate inter-ethnic and inter-patient differences in OSI pharmacokinetics (PK) and determine optimal dosing regimens. Methods: Population PBPK models of OSI for healthy and disease populations were developed using physicochemical and biochemical properties of OSI and physiological parameters of different groups. And then the PBPK models were validated using the multiple clinical PK and drug-drug interaction (DDI) study data. Results: The model demonstrated good consistency with the observed data, with most of prediction-to-observation ratios of 0.8-1.25 for AUC, Cmax, and Ctrough. The PBPK model revealed that plasma exposure of OSI was approximately 2-fold higher in patients compared to healthy individuals, and higher exposure observed in Caucasians compared to other ethnic groups. This was primarily attributed to a lower CL/F of OSI in patients and Caucasian. The PBPK model displayed that key factors influencing PK and EGFRm+ inhibition differences included genetic polymorphism of CYP3A4, CYP1A2 expression, plasma free concentration (fup), albumin level, and auto-inhibition/induction on CYP3A4. Inter-patient PK variability was most influenced by CYP3A4 variants, fup, and albumin level. The PBPK simulations indicated that the optimal dosing regimen for patients across the three populations of European, Japanese, and Chinese ancestry was OSI 80 mg once daily (OD) to achieve the desired range of plasma Ctrough (328-677 nmol/L), as well as 80 mg and 160 mg OD for desirable pulmonary EGFRm+ inhibition (>80%). Conclusion: In conclusion, this study's PBPK simulations highlighted potential ethnic and inter-patient variability in OSI PK and EGFRm+ inhibition between Caucasian, Japanese, and Chinese populations, while also providing insights into optimal dosing regimens of OSI.

Effects of the CYP3A inhibitors, voriconazole, itraconazole, and fluconazole on the pharmacokinetics of osimertinib in rats

Background

Osimertinib, as third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), is the first-line treatment approved to treat advanced T790M mutation-positive tumors. Triazole antifungals are therapeutic drugs for cancer patients to reduce the risk of opportunistic fungal infections. Our objective was to investigate whether three triazole antifungals (voriconazole, itraconazole, and fluconazole) could change the pharmacokinetics of osimertinib in rats.

Methods

The adult male Sprague-Dawley rats were randomly divided into four groups (n = 6): control (0.3% CMC-Na), and voriconazole (20 mg/kg), itraconazole (20 mg/kg), or fluconazole (20 mg/kg) combined with osimertinib (10 mg/kg) group. Tail vein blood samples were collected into heparin tubes at various time points within 0-48 h after osimertinib administration. Osimrtinib's plasma concentration was detected using HPLC-MS/MS system equipped with a Waters XBridge C18 column, with the mobile phase consisting of acetonitrile and 0.2% formic acid water at a flow rate of 0.5 mL/min.

Results

Co-administration with voriconazole or fluconazole increased the Cmax of osimertinib by 58.04% and 53.45%, respectively; the AUC0-t increased by 62.56% and 100.98%, respectively. However, when co-administered with itraconazole, the Cmax and AUC0-t of osimertinib only increased by 13.91% and 34.80%, respectively.

Conclusions

Our results revealed that the pharmacokinetics of osimertinib were significantly changed by voriconazole and fluconazole in rats, whereas it was slightly affected by itraconazole. This work will contribute to a more comprehensive understanding of the pharmacokinetic properties of osimertinib when co-administered with triazole antifungals.

Repurposing antifungal drugs for cancer therapy

BACKGROUND

Repurposing antifungal drugs in cancer therapy has attracted unprecedented attention in both preclinical and clinical research due to specific advantages, such as safety, high-cost effectiveness and time savings compared with cancer drug discovery. The surprising and encouraging efficacy of antifungal drugs in cancer therapy, mechanistically, is attributed to the overlapping targets or molecular pathways between fungal and cancer pathogenesis. Advancements in omics, informatics and analytical technology have led to the discovery of increasing "off-site" targets from antifungal drugs involved in cancerogenesis, such as smoothened (D477G) inhibition from itraconazole in basal cell carcinoma.

AIM OF REVIEW

This review illustrates several antifungal drugs repurposed for cancer therapy and reveals the underlying mechanism based on their original target and "off-site" target. Furthermore, the challenges and perspectives for the future development and clinical applications of antifungal drugs for cancer therapy are also discussed, providing a refresh understanding of drug repurposing.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review may provide a basic understanding of repurposed antifungal drugs for clinical cancer management, thereby helping antifungal drugs broaden new indications and promote clinical translation.

Drug-drug interaction potential of SH-1028, a third-generation EGFR-TKI: in vitro and clinical trials

SH-1028 is an irreversible third-generation EGFR tyrosine kinase inhibitor (EGFR-TKI) for the treatment of locally advanced or metastatic non-small cell lung cancer (NSCLC). Considering the possibility of combination therapy in patients with NSCLC, we investigated the drug-drug interaction (DDI) potential of SH-1028 both in vitro and in clinical trials. The in vitro studies were conducted to determine the potential of SH-1028 as a substrate, inducer, or inhibitor of cytochrome P450 (CYP) subtypes. A phase I drug-drug interaction study in healthy volunteers was performed to evaluate the impact of co-administering rifampicin (a strong CYP3A4 inducer) and itraconazole (a strong CYP3A4 inhibitor) on the pharmacokinetics of SH-1028. The in vitro experiments showed that SH-1028 was mainly metabolized by CYP3A4. The activities of CYP1A2, 2B6, 2C19, 2D6 and 3A4 enzymes were slightly inhibited in vitro with SH-1028. SH-1028 has no obvious induction effect on CYP1A2 and CYP2B6 activities, but has potential induction effect on CYP3A4 mRNA expression. However, SH-1028 may not induce or inhibit human CYPs significantly at the clinically expected dose (200 mg). The geometric mean ratios of pharmacokinetic parameters and their corresponding 90% confidence intervals for SH-1028 in combination and alone did not fall within the range of 80-125%. It is speculated that itraconazole and rifampicin affect the metabolism of SH-1028. In the clinical application of SH-1028, special attention should be paid to the interaction between SH-1028 and drugs or foods that affect the activity of CYP3A4. (Clinical trial registration number: CTR20210558).

Considering the Oral Bioavailability of Protein Kinase Inhibitors: Essential in Assessing the Extent of Drug-Drug Interaction and Improving Clinical Practice

Protein kinase inhibitors share pharmacokinetic (PK) pathways among themselves. They are all metabolized by several cytochromes P450 (CYP). For most of them, CYP3A4 is the predominant metabolic pathway. However, their oral bioavailability differs. For example, the oral bioavailability of imatinib has been estimated at nearly 100%, but that of ibrutinib averages 3% due to its high hepatic first-pass effect. Overall, the smaller the oral bioavailability, the larger its interindividual PK variability. Indeed, for drugs with low oral bioavailability, the extent of their absorption is an additional cause (along with elimination variability) of differences in drug exposure among patients. The impact of drug-drug interaction (DDI) also differs between drugs with low or high oral bioavailability. We describe and explain why the impact of CYP3A4 inhibitors and inducers is much greater for protein kinase inhibitors with low oral bioavailability. The effect of food on protein kinase inhibitors and DDIs corresponding to plasma protein binding will also be considered. Finally, the benefits of these concepts in clinical practice (including therapeutic drug monitoring) will be discussed. Overall, our main objective was to apply fundamental PK concepts to understanding the main clinical issues of these oral anticancer drugs.

Effects of CYP3A4/5 and ABC transporter polymorphisms on osimertinib plasma concentrations in Japanese patients with non-small cell lung cancer

The effects of polymorphisms in CYP3A4 (20230G > A), CYP3A5 (6986A > G), ABCB1 (1236C > T, 2677G > T/A, 3435C > T), ABCG2 (421C > A), and ABCC2 (-24C > T) on the area under the concentration-time curve (AUC) of osimertinib in 23 patients with non-small cell lung cancer were investigated. Blood sampling was performed just prior to and at 1, 2, 4, 6, 8, 12, and 24 h after osimertinib administration at the steady-state on day 15 after beginning therapy. The osimertinib AUC_0-24 was significantly correlated with age (P = 0.038), serum albumin (P = 0.002), and serum creatinine (P = 0.012). Additionally, there were significant differences in the AUC_0-24 of osimertinib among the groups administered vonoprazan, histamine 2-receptor antagonists or esomeprazole, and no acid suppressants (P = 0.021). By contrast, there were no significant differences in the AUC_0-24 of osimertinib between genotypes of CYP3A4/5 or ABC transporters. Furthermore, there were no significant differences in the AUC_0-24 of osimertinib between patients with diarrhea, skin rash, or hepatotoxicity and those without these conditions. In multivariate analysis, only serum albumin value was an independent factor predicting the AUC_0-24 of osimertinib. Analysis of CYP3A4/5 and ABC transporter polymorphisms before osimertinib therapy may not predict the efficacy or side effects of osimertinib. The lower serum albumin values were associated with an increase in the AUC_0-24 of osimertinib; however, further studies are needed to assess the factors contributing to the interindividual variability of osimertinib pharmacokinetics.

Differential effects of ketoconazole, fluconazole, and itraconazole on the pharmacokinetics of pyrotinib in vitro and in vivo

It has been reported that drug-drug interactions (DDIs) can affect the pharmacokinetics and pharmacodynamics of various oral drugs. To better understand the effects of azole antifungal drugs (ketoconazole, fluconazole, and itraconazole) on pyrotinib’s pharmacokinetics, DDIs between pyrotinib and three azoles were studied with Sprague-Dawley (SD) rat liver microsomes in vitro. Additionally, in vivo pyrotinib metabolic experiment was also performed. Twenty-four male SD rats were randomly divided into four groups: the ketoconazole (40 mg/kg), fluconazole (40 mg/kg), itraconazole (40 mg/kg), and the control group. UPLC-MS/MS was used for the determination of Pyrotinib’s plasma concentration in rats. In vitro experiments showed that IC₅₀ values of ketoconazole, fluconazole and itraconazole were 0.06, 11.55, and 0.27 μM, respectively, indicating that these drugs might reduce the clearance rate of pyrotinib at different degrees. In rat studies, coadministration of pyrotinib with ketoconazole or fluconazole could dramatically increase the C_max and AUC_(0-t) values and decrease the clearance rate of pyrotinib, especially for ketoconazole. However, coadministration with itraconazole had no impact on the pharmacokinetic characters of pyrotinib. These data indicated that ketoconazole and fluconazole could significantly decrease the metabolism of pyrotinib both in vitro and in vivo. More attentions should be paid when pyrotinib is combined with azole antifungal drugs in clinic although further investigation is still required in future.

Exposure-Response Analysis of Osimertinib in Patients with Advanced Non-Small-Cell Lung Cancer

High interindividual variability (IIV) of the clinical response to epidermal growth factor receptor (EGFR) inhibitors such as osimertinib in non-small-cell lung cancer (NSCLC) might be related to the IIV in plasma exposure. The aim of this study was to evaluate the exposure−response relationship for toxicity and efficacy of osimertinib in unselected patients with advanced EGFR-mutant NSCLC. This retrospective analysis included 87 patients treated with osimertinib. Exposure−toxicity analysis was performed in the entire cohort and survival analysis only in second-line patients (n = 45). No significant relationship between occurrence of dose-limiting toxicity and plasma exposure was observed in the entire cohort (p = 0.23, n = 86). The median overall survival (OS) was approximately two-fold shorter in the 4th quartile (Q4) of osimertinib trough plasma concentration (>235 ng/mL) than in the Q1−Q3 group (12.2 months [CI95% = 8.0−not reached (NR)] vs. 22.7 months [CI95% = 17.1−34.1]), but the difference was not statistically significant (p = 0.15). To refine this result, the exposure−survival relationship was explored in a cohort of 41 NSCLC patients treated with erlotinib. The Q4 erlotinib exposure group (>1728 ng/mL) exhibited a six-fold shorter median OS than the Q1−Q3 group (4.8 months [CI95% = 3.3-NR] vs. 22.8 months (CI95% = 10.6−37.4), p = 0.00011). These results suggest that high exposure to EGFR inhibitors might be related to worse survival in NSCLC patients.

A commentary on the use of pharmacoenhancers in the pharmaceutical industry and the implication for DMPK drug discovery strategies

Paxlovid, a drug combining nirmatrelvir and ritonavir, was designed for the treatment of COVID-19 and its rapid development has led to emergency use approval by the FDA to reduce the impact of COVID-19 infection on patients.In order to overcome potentially suboptimal therapeutic exposures, nirmatrelvir is dosed in combination with ritonavir to boost the pharmacokinetics of the active product.Here we consider examples of drugs co-administered with pharmacoenhancers.Pharmacoenhancers have been adopted for multiple purposes such as ensuring therapeutic exposure of the active product, reducing formation of toxic metabolites, changing the route of administration, and increasing the cost-effectiveness of a therapy.We weigh the benefits and risks of this approach, examining the impact of technology developments on drug design and how enhanced integration between cross-discipline teams can improve the outcome of drug discovery.

[Application of MIDD in Clinical Research of Antitumor Drugs]

The antitumor drug has become one of the focused areas in new drug research and development. Their clinical research generally consumes a long period of time, with high cost and high risk. Model-informed drug development (MIDD) integrates and quantitatively analyzes physiological, pharmacological, and disease progression information through modeling and simulation, which can reduce the cost of drug development and improve the efficiency of clinical research. In this essay, Osimertinib and Pembrolizumab are given as examples to illustrate the specific application of MIDD in different phases of clinical research, aiming to provide references for the application of MIDD to guide the clinical research of antitumor drugs.
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Determination of Osimertinib, Aumolertinib, and Furmonertinib in Human Plasma for Therapeutic Drug Monitoring by UPLC-MS/MS

The third-generation epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), osimertinib, aumolertinib, and furmonertinib represent a new treatment option for patients with EGFR p.Thr790 Met (T790 M)-mutated non-small cell lung cancer (NSCLC). Currently, there are no studies reporting the simultaneous quantification of these three drugs. A simple ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the simultaneous quantitative determination of osimertinib, aumolertinib, and furmonertinib concentrations in human plasma, and it was applied for therapeutic drug monitoring (TDM). Plasma samples were processed using the protein precipitation method (acetonitrile). A positive ion monitoring mode was used for detecting analytes. D₃-Sorafenib was utilized as the internal standard (IS), and the mobile phases were acetonitrile (containing 0.1% formic acid) and water with gradient elution on an XSelect HSS XP column (2.1 mm × 100.0 mm, 2.5 µm, Waters, Milford, MA, USA) at a flow rate of 0.5 mL·min⁻¹. The method’s selectivity, precision (coefficient of variation of intra-day and inter-day ≤ 6.1%), accuracy (95.8–105.2%), matrix effect (92.3–106.0%), extraction recovery, and stability results were acceptable according to the guidelines. The linear ranges were 5–500 ng·mL⁻¹, 2–500 ng·mL⁻¹, and 0.5–200 ng·mL⁻¹ for osimertinib, aumolertinib, and furmonertinib, respectively. The results show that the method was sensitive, reliable, and simple and that it could be successfully applied to simultaneously determine the osimertinib, aumolertinib, and furmonertinib blood concentrations in patients. These findings support using the method for TDM, potentially reducing the incidence of dosing blindness and adverse effects due to empirical dosing and inter-patient differences.

Three Third-Generation Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors in Non-Small Cell Lung Cancer: Similarities and Differences

Osimertinib, almonertinib and furmonertinib are third-generation epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) approved for non-small cell lung cancer (NSCLC) patients with EGFR T790M mutation. This article reviews research advances in pharmacokinetics, pharmacodynamics, treatment-related adverse events, and other aspects related to the three EGFR-TKIs were systematically reviewed in order to provide references for clinical drug selection. There are differences in dosing schedule and incidence of adverse events among three drugs. Optimization of third-generation EGFR-TKIs options for individuals may produce the maximal benefits to NSCLC patients with EGFR T790M mutation.

Osimertinib-Centered Therapy Against Uncommon Epidermal Growth Factor Receptor-Mutated Non-Small-Cell Lung Cancer- A Mini Review

Osimertinib is a third-generation, irreversible mutant epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that is approved by the U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA). Osimertinib is currently the first line drug recommended by National Comprehensive Cancer Network (NCCN) guidelines against lung cancer harboring the EGFR TKI-sensitive mutation and acquired EGFR T790M resistance mutation. Osimertinib demonstrated some efficacy in clinical trials and case reports in patients bearing certain uncommon EGFR mutations, but it is not active in patients with other mutations such as C797S. This mini-review presents the mechanisms underlying the variations in patient responses, discusses the use of osimertinib against non-small-cell lung carcinomas with uncommon EGFR mutations, and addresses the future prospects of osimertinib-centered therapy.

Antifungal Drugs TDM: Trends and Update

PURPOSE

The increasing burden of invasive fungal infections results in growing challenges to antifungal (AF) therapeutic drug monitoring (TDM). This review aims to provide an overview of recent advances in AF TDM.

METHODS

We conducted a PubMed search for articles during 2016-2020 using "TDM" or "pharmacokinetics" or "drug-drug-interaction" with "antifungal," consolidated for each AF. Selection was limited to English language articles with human data on drug exposure.

RESULTS

More than 1000 articles matched the search terms. We selected 566 publications. The latest findings tend to confirm previous observations in real-life clinical settings. The pharmacokinetic variability related to special populations is not specific but must be considered. AF benefit-to-risk ratio, drug-drug interaction (DDI) profiles, and minimal inhibitory concentrations for pathogens must be known to manage at-risk situations and patients. Itraconazole has replaced ketoconazole in healthy volunteers DDI studies. Physiologically based pharmacokinetic modeling is widely used to assess metabolic azole DDI. AF prophylactic use was studied more for Aspergillus spp. and Mucorales in oncohematology and solid organ transplantation than for Candida (already studied). Emergence of central nervous system infection and severe infections in immunocompetent individuals both merit special attention. TDM is more challenging for azoles than amphotericin B and echinocandins. Fewer TDM requirements exist for fluconazole and isavuconazole (ISZ); however, ISZ is frequently used in clinical situations in which TDM is recommended. Voriconazole remains the most challenging of the AF, with toxicity limiting high-dose treatments. Moreover, alternative treatments (posaconazole tablets, ISZ) are now available.

CONCLUSIONS

TDM seems to be crucial for curative and/or long-term maintenance treatment in highly variable patients. TDM poses fewer cost issues than the drugs themselves or subsequent treatment issues. The integration of clinical pharmacology into multidisciplinary management is now increasingly seen as a part of patient care.

Concomitant Pulmonary Tuberculosis Impair Survival in Advanced Epidermal Growth Factor Receptor (EGFR) Mutant Lung Adenocarcinoma Patients Receiving EGFR-Tyrosine Kinase Inhibitor

Objective

Limited studies have clearly demonstrated the effect of EGFR-TKI in the treatment of EGFR mutant NSCLC patients with underlying pulmonary disease, like pulmonary tuberculosis (PTB). Here, we conducted the study to evaluate the impact of PTB on survival of Chinese EGFR mutant lung adenocarcinoma (LUAD) patients that underwent EGFR-TKI treatment.

Methods

Clinicopathologic data of 1448 LUAD patients harboring EGFR mutations from the Guangzhou Chest Hospital between 2017 and 2019 were reviewed retrospectively. Patients receiving EGFR-TKI treatment were divided into PTB and non-PTB groups. The differences in response to EGFR-TKIs and survival between the two groups were assessed.

Results

After EGFR-TKIs treatment, the objective response rate (58.14% vs 47.62%) as well as disease control rate (97.67% vs 85.71%) were higher in the non-PTB group than in the PTB group, but there was no statistical difference. In the survival analysis, both the median progression-free survival (7.47 months vs 11.77 months, p = 0.038) and the overall survival (13.00 months vs 20.00 months, p = 0.001) were significantly shorter in the PTB group than in the non-PTB group. Furthermore, for patients with 19Del mutation, or metastases sites less than 3, or using first-line EGFR-TKI, EGFR-TKIs treatment significantly prolonged the median PFS and OS in patients without PTB.

Conclusion

LUAD patients with concomitant PTB have a poor response to EGFR-TKI treatment, especially in terms of survival outcome.

A Review of CYP3A Drug-Drug Interaction Studies: Practical Guidelines for Patients Using Targeted Oral Anticancer Drugs

Many oral anticancer drugs are metabolized by CYP3A. Clinical drug-drug interaction (DDI) studies often only examine the effect of strong CYP3A inhibitors and inducers. The effect of moderate or weak inhibitors or inducers can be examined using physiologically based pharmacokinetic simulations, but data from these simulations are not always available early after approval of a drug. In this review we provide recommendations for clinical practice on how to deal with DDIs of oral anticancer drugs if only data from strong CYP3A inhibitors or inducers is available. These recommendations were based on reviewed data of oral anticancer drugs primarily metabolized by CYP3A and approved for the treatment of solid tumors from January 1st, 2013 to December 31st, 2015. In addition, three drugs that were registered before the new EMA guideline was issued (i.e., everolimus, imatinib, and sunitinib), were reviewed. DDIs are often complex, but if no data is available from moderate CYP3A inhibitors/inducers, a change in exposure of 50% compared with strong inhibitors/inducers can be assumed. No a priori dose adaptations are indicated for weak inhibitors/inducers, because their interacting effect is small. In case pharmacologically active metabolites are involved, the metabolic pathway, the ratio of the parent to the metabolites, and the potency of the metabolites should be taken into account.

Evaluation of the pharmacokinetic effects of itraconazole on alflutinib (AST2818): an open-label, single-center, single-sequence, two-period randomized study in healthy volunteers

Alflutinib (AST2818) is a newly developed third-generation EGFR tyrosine kinase inhibitor for the treatment of lung cancer patients with T790M-resistant mutations. It is metabolized mainly by the CYP3A4 enzyme. At the same time, it has the potential to induce CYP3A4. In this study, we aimed to estimate the effect of itraconazole (a strong inhibitor of CYP3A4) on the pharmacokinetics of alflutinib. For this aim, a single-center, open-label, single-sequence, two-period trial was designed. The pharmacokinetic parameters of AST2818 and its active metabolite AST5902 were established from blood concentration measurements, and adverse events (AEs) of two periods of treatment were documented. For AST2818, the C_max, AUC_0-t, and AUC_0-∞ in period II (coadministration of itraconazole) increased by 6.5 ng/mL, 1263.0 h*ng/mL, and 1067.0 h*ng/mL, respectively. And the corresponding 90% CIs were 1.23 (1.14-1.32), 2.41 (2.29-2.54), and 2.22 (2.11-2.34), respectively. The C_max, AUC_0-t, and AUC_0-∞ of AST5902 in period II decreased by 4.849 ng/mL, 415.60 h*ng/mL, and 391.4 h*ng/mL, respectively. Moreover, the corresponding 90% CIs were 0.09 (0.08-0.10), 0.18 (0.17-0.19), and 0.14 (0.13-0.15), respectively. Nonetheless, in period II, plasma concentrations of total active components (AST2818 and AST5902) changed marginally. The AUC_0-∞ of total active components increased 60%, and the corresponding C_max increased 8%. Possible treatment-related AEs assessed by investigators were fewer in period II (23.3% vs 36.7%). In conclusion, the total exposure of AST2818 and active metabolite AST5902 increased following the coadministration of itraconazole, but it was still safe and well-tolerated.

Effects of Itraconazole and Rifampin on the Pharmacokinetics of Mobocertinib (TAK-788), an Oral Epidermal Growth Factor Receptor Inhibitor, in Healthy Volunteers

Mobocertinib (TAK‐788) is an investigational oral tyrosine kinase inhibitor targeting epidermal growth factor receptor and human epidermal growth factor 2. A phase 1 open‐label, 2‐period, fixed‐sequence, 2‐part study (NCT03928327) characterized effects of a strong CYP3A4 inhibitor (itraconazole) and inducer (rifampin) on the pharmacokinetics (PK) of mobocertinib and its active metabolites, AP32960 and AP32914. Healthy volunteers (n = 12 per part) received a single dose of mobocertinib alone (20 mg, part 1; 160 mg, part 2) and with multiple doses of itraconazole 200 mg once daily (part 1) or rifampin 600 mg once daily (part 2). Coadministration of itraconazole with mobocertinib increased the combined molar area under the plasma concentration‐time curve from time 0 to infinity (AUC_0‐∞) of mobocertinib, AP32960, and AP32914 by 527% (geometric least‐squares mean [LSM] ratio, 6.27; 90% confidence interval [CI], 5.20‐7.56). Coadministration of rifampin with mobocertinib decreased the combined molar AUC_0‐∞ of mobocertinib, AP32960, and AP32914 by 95% (geometric LSM ratio, 0.05; 90%CI, 0.04‐0.07). Based on these results, the strong CYP3A inhibitor itraconazole and inducer rifampin significantly influenced the PK of mobocertinib and its active metabolites. Coadministration of mobocertinib with moderate and strong CYP3A inhibitors or inducers is not recommended in ongoing clinical trials.

In vitro inhibition of human UDP-glucuronosyltransferase (UGT) 1A1 by osimertinib, and prediction of in vivo drug-drug interactions

Osimertinib is the only third-generation epidermal growth factor receptor tyrosine-kinase inhibitor (EGFR-TKI) approved by Food and Drug Administration (FDA). This study aimed to know the inhibitory effect of osimertinib on human UDP-glucosyltransferases (UGTs) and human liver microsomes (HLMs), as well as to identify its potential to cause drug-drug interaction (DDI) arising from the modulation of UGT activity. High inhibitory effect of osimertinib was shown towards UGT1A1, 1A3, 1A6, 1A7, 1A8, 1A10, 2B7 and 2B15. Especially, osimertinib exhibited competitive inhibition against UGT1A1 with a K_i,u of 0.87 ± 0.12 μM. It also noncompetitively inhibited SN-38 glucuronidation in pooled HLMs with a K_i,u of 3.32 ± 0.25 μM. Results from quantitative prediction study indicated that osimertinib administered at 80 mg/day may result in a 4.83 % increase in the AUC of drugs mainly metabolized by UGT1A1, implying low risk of DDI via liver metabolism. However, the ratios of [I]_gut/K_i,u are much higher than 11 in HLMs and recombinant UGT1A1, indicating a risk for interaction in intestine. The effects of osimertinib on intestinal UGT should be paid more attention on to avoid unnecessary clinical DDI risks.

Potential Cytochrome P450-mediated pharmacokinetic interactions between herbs, food, and dietary supplements and cancer treatments

Herbs, food and dietary supplements (HFDS), can interact significantly with anticancer drug treatments via cytochrome p450 isoforms (CYP) CYP3A4, CYP2D6, CYP1A2, and CYP2C8. The objective of this review was to assess the influence of HFDS compounds on these cytochromes. Interactions with CYP activities were searched for 189 herbs and food products, 72 dietary supplements in Web of Knowledge® databases. Analyses were made from 140 of 3,125 clinical trials and 236 of 3,374 in vitro, animal model studies or case reports. 18 trials were found to report direct interactions between 9 HFDS with 8 anticancer drugs. 21 HFDS were found to interact with CYP3A4, a major metabolic pathway for many anticancer drugs. All 261 HFDS were classified for their interaction with the main cytochromes P450 involved in the metabolism of anticancer drugs. We provided an easy-to-use colour-coded table to easily match potential interactions between 261 HFDS and 117 anticancer drugs.

An overview of osimertinib as a treatment of non-small cell lung cancer (NSCLC): an update

Introduction: Osimertinib is a third-generation anti-epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), that irreversibly binds to mutant EGFR, specifically to the T790M EGFR mutant non-small cell lung cancer (NSCLC). Since its approval, osimertinib has been tested in multiple scenarios, including the first-line and adjuvant setting of EGFR-mutant disease.Areas covered: The authors summarize the most recent evidence about osimertinib in NSCLC, covering its use as a first-line therapy, its activity on central nervous system metastatic disease, and in elderly patients. Moreover, the authors focus on resistance to this drug and on the therapeutic strategies that may be used to overcome this issue.Expert opinion: Osimertinib is a key player in the treatment ofEGFR mutant NSCLC and will probably be used in earlier clinical settings in the future, giving rise to an emerging variety of resistance mechanisms. These could be potentially overcome in several ways: e.g. as an oligo-progressive disease local therapy, maintaining osimertinib might be a reasonable option; however, for widespread progressive disease, a switch to chemotherapy should be considered. Finally, either liquid biopsy or tissue biopsy might be considered in patients progressing to osimertinib, as they can lead to the identification of potentially targetable resistance mechanisms.

Effects of rifampicin on the pharmacokinetics of alflutinib, a selective third-generation EGFR kinase inhibitor, and its metabolite AST5902 in healthy volunteers

Background Alflutinib is a novel irreversible and highly selective third-generation EGFR inhibitor currently being developed for the treatment of non-small cell lung cancer patients with activating EGFR mutations and EGFR T790M drug-resistant mutation. Alflutinib is mainly metabolized via CYP3A4 to form its active metabolite AST5902. Both alflutinib and AST5902 contribute to the in vivo pharmacological activity. The aim of this study was to investigate the effects of rifampicin (a strong CYP3A4 inducer) on the pharmacokinetics of alflutinib and AST5902 in healthy volunteers, thus providing important information for drug-drug interaction evaluation and guiding clinical usage. Methods This study was designed as a single-center, open-label, and single-sequence trial over two periods. The volunteers received a single dose of 80 mg alflutinib on Day 1/22 and continuous doses of 0.6 g rifampicin on Day 15-30. Blood sampling was conducted on Day 1-10 and Day 22-31. The pharmacokinetics of alflutinib, AST5902, and the total active ingredients (alflutinib and AST5902) with or without rifampicin co-administration were respectively analyzed. Results Co-administration with rifampicin led to 86% and 60% decreases in alflutinib AUC_0-∞ and C_max, respectively, as well as 17% decrease in AST5902 AUC_0-∞ and 1.09-fold increase in AST5902 C_max. The total active ingredients (alflutinib and AST5902) exhibited 62% and 39% decreases in AUC_0-∞ and C_max, respectively. Conclusions As a strong CYP3A4 inducer, rifampicin exerted significant effects on the pharmacokinetics of alflutinib and the total active ingredients (alflutinib and AST5902). The results suggested that concomitant strong CYP3A4 inducers should be avoided during alflutinib treatment. This trial was registered at http://www.chinadrugtrials.org.cn . The registration No. is CTR20191562, and the date of registration is 2019-09-12.

An UPLC-MS/MS Method for Determination of Osimertinib in Rat Plasma: Application to Investigating the Effect of Ginsenoside Rg3 on the Pharmacokinetics of Osimertinib

Osimertinib is a novel oral, potent, and irreversible epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) for treatment of advanced T790M mutation-positive advanced non-small cell lung cancer, which is commonly combined with ginsenoside Rg3 in clinic to enhance the efficacy and minimize adverse reactions. In the present study, a highly sensitive UPLC-MS/MS method was established and validated for analysis of osimertinib in rat plasma according to US FDA guideline. Separation was performed on a C18 (2.1 × 50 mm, 2.6 μm) column using a gradient elution of ammonium formate (10 mM) with 0.1% formic acid buffer (A) and ACN (B) at a flow rate of 0.2 mL/min. Detection was carried out on a triple quadrupole tandem mass spectrometer equipped with electrospray ionization in the MRM mode. The method was validated over a concentration range of 1-400 ng/mL for osimertinib. The intra- and interday accuracy and precision values were within ±15%. No significant degradation occurred under the experimental conditions in stability assays. There was a further investigation on the effects of multiple doses of ginsenoside Rg3 on the pharmacokinetics of osimertinib in rats for the first time. The results implied that osimertinib exhibited a slow absorption and moderate-rate elimination in rats following oral administration. Coadministeration with ginsenoside Rg3 (5 mg/kg, 7 days, i.g.) may have no effect on the pharmacokinetics of osimertinib in rats. The results provide a reference for the clinical concomitant medications of Rg3 and osimertinib.

Alflutinib (AST2818), primarily metabolized by CYP3A4, is a potent CYP3A4 inducer

Alflutinib (AST2818) is a third-generation epidermal growth factor receptor (EGFR) inhibitor that inhibits both EGFR-sensitive mutations and T790M mutations. Previous study has shown that after multiple dosages, alflutinib exhibits nonlinear pharmacokinetics and displays a time- and dose-dependent increase in the apparent clearance, probably due to its self-induction of cytochrome P450 (CYP) enzyme. In this study, we investigated the CYP isozymes involved in the metabolism of alflutinib and evaluated the enzyme inhibition and induction potential of alflutinib and its metabolites. The data showed that alflutinib in human liver microsomes (HLMs) was metabolized mainly by CYP3A4, which could catalyze the formation of AST5902. Alflutinib did not inhibit CYP isozymes in HLMs but could induce CYP3A4 in human hepatocytes. Rifampin is a known strong CYP3A4 inducer and is recommended by the FDA as a positive control in the CYP3A4 induction assay. We found that the induction potential of alflutinib was comparable to that of rifampin. The Emax of CYP3A4 induction by alflutinib in three lots of human hepatocytes were 9.24-, 11.2-, and 10.4-fold, while the fold-induction of rifampin (10 μM) were 7.22-, 19.4- and 9.46-fold, respectively. The EC50 of alflutinib-induced CYP3A4 mRNA expression was 0.25 μM, which was similar to that of rifampin. In addition, AST5902 exhibited much weak CYP3A4 induction potential compared to alflutinib. Given the plasma exposure of alflutinib and AST5902, both are likely to affect the pharmacokinetics of CYP3A4 substrates. Considering that alflutinib is a CYP3A4 substrate and a potent CYP3A4 inducer, drug-drug interactions are expected during alflutinib treatment.

Polypharmacy among older advanced lung cancer patients taking EGFR tyrosine kinase inhibitors

OBJECTIVE

Polypharmacy (PP) is a common problem among the older adults and has a potential effect on health-related problems. However, the significance of PP in older advanced non-small cell lung cancer (NSCLC) patients and those on oral molecular-targeted anticancer agents is unclear.

MATERIALS AND METHODS

This retrospective, nonrandomized study reviewed the records of 334 advanced NSCLC patients who underwent epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) treatment. PP was defined as ≥ 5 concomitant medications. Potentially inappropriate medication (PIM) use was measured using the updated screening tool of older people's prescriptions (STOPP) ver. 2 criteria. We also estimated survival distributions using the Kaplan-Meier method, compared between-group differences using the log-rank test, explored potential predictors of survival using Cox regression, and performed cluster analysis to identify factors affecting multiple-medication use.

RESULTS

The PP and PIM use prevalence was 38.4% and 31.9%, respectively. The median overall survival (OS) for PP(+) and PP(-) patients was 19.4 and 27.3 months, respectively. Multivariate analysis revealed a significant correlation between PP and OS. The frequency of unexpected hospitalization during EGFR-TKI treatment was higher in PP(+) patients compared to PP(-) patients (49.4% vs. 29.4%; odds ratio = 2.34).

CONCLUSION

PP is an independent prognostic factor in older advanced NSCLC patients taking EGFR-TKIs. PP can be used as a simple indicator of such patients' comorbidities and symptoms or as a predictive marker of unexpected hospitalization during treatment.

A multicenter, phase I, pharmacokinetic study of osimertinib in cancer patients with normal renal function or severe renal impairment

Osimertinib is a third-generation, irreversible, oral epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) that potently and selectively inhibits both EGFR-TKI sensitizing and EGFR T790M and has demonstrated efficacy in non-small cell lung cancer (NSCLC) central nervous system metastases. In this phase I study, we assessed the effects of normal renal function (NRF) and severe renal impairment (SRI) on the pharmacokinetics (PK) of osimertinib in patients with solid tumors. Part A: patients with NRF (creatinine clearance [CrCL] ≥90 mL/min), and SRI, (CrCL <30 mL/min), received a single 80-mg oral dose of osimertinib and standard PK measures were assessed. Part B: patients with SRI were treated for 3 months to obtain safety data, if deemed clinically appropriate. The geometric mean osimertinib plasma concentrations were higher in patients with SRI (n = 7) vs NRF (n = 8) and were highly variable. Osimertinib exposure based on Cmax and area under the plasma concentration-time curve, was 1.19-fold (90% CI: 0.6, 2.0) and 1.85-fold (90% CI: 0.9, 3.6), respectively, higher for patients with SRI vs patients with NRF, with no clear correlation between CrCL and exposure. No new safety signals were identified after 12 weeks of osimertinib 80 mg continuous dosing. PK parameters pooled across this study and other phase I, II, and III osimertinib clinical studies (exploratory population PK analysis), showed minimal correlation between CrCL and total clearance. In conclusion, no dose adjustment is required for osimertinib for patients with SRI.

A review of Osimertinib in NSCLC and pharmacist role in NSCLC patient care

Lung cancer is a complex, genetically heterogeneous disease. It is the most common cause of cancer-related deaths worldwide. Non-small cell lung cancer (NSCLC) represents the majority of the diagnosed lung cancer cases. Osimertinib is a new treatment option that demonstrated a superior efficacy over standard epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) or platinum-based chemotherapy. The safety and efficacy of osimertinib (a third generation EGFR-TKIs) were confirmed by well-designed clinical trials. Consequently, osimertinib was considered a first-line treatment option, particularly in patients with EGFR mutant NSCLC. It has been approved by FDA for the treatment of advance or metastatic NSCLC patients with specific EGFR-mutant NSCLC. As an active member of the multidisciplinary team, pharmacist has a promising role in assuring safe, effective and cost-effective treatment in patient with NSCLC. This review article aims to highlight the latest evidence about osimertinib use as a new treatment option in the clinical practice and to review the potential pharmacist key roles in NSCLC patient care.

Dual EGFR and ABL Tyrosine Kinase Inhibitor Treatment in a Patient with Concomitant EGFR-Mutated Lung Adenocarcinoma and BCR-ABL1-Positive CML

Tyrosine kinase inhibitor (TKI) combination is expected to increase in the era of precision medicine. TKI combination may be required to treat double primary cancers, each having a targetable gene, or to treat a single malignancy with multiple targetable genes. Here, we demonstrate the first report of dual EGFR and ABL TKI treatment in a patient with concomitant EGFR-mutated lung adenocarcinoma and BCR-ABL1-positive chronic myeloid leukemia (CML). A 60-year-old man with an 8-year history of CML was diagnosed as advanced EGFR-mutated lung adenocarcinoma. Complete molecular response of CML had been achieved by imatinib, and ABL-TKI had been switched to nilotinib four years previously due to muscle cramps. We discontinued nilotinib and started afatinib. Although partial response of lung adenocarcinoma was achieved, cytogenetic relapse of CML was observed following nilotinib discontinuation. We applied the previously described framework of cytochrome P450 3A4-mediated oral drug-drug interactions and selected gefitinib and nilotinib to treat both malignancies. We effectively and safely administered this combination for seven months. The present report is the first to demonstrate the safety and efficacy of dual EGFR and ABL TKI treatment in a patient with concomitant EGFR-mutated lung adenocarcinoma and CML.

A phase 1/1b study of PUR1900, an inhaled formulation of itraconazole, in healthy volunteers and asthmatics to study safety, tolerability and pharmacokinetics

AIMS

Oral itraconazole has variable pharmacokinetics and risks of adverse events associated with high plasma exposure. An inhalation formulation of itraconazole (PUR1900) is being developed to treat allergic bronchopulmonary aspergillosis, an allergic inflammatory disease occurring in asthmatics and patients with cystic fibrosis.

METHODS

A 3-part, open-label Phase 1 study was conducted to evaluate safety, tolerability and pharmacokinetics of PUR1900. Healthy volunteers (n = 5-6/cohort) received either single (Part 1) or multiple (Part 2) ascending doses of PUR1900 for up to 14 days. In Part 3 stable, adult asthmatics received a single dose of 20 mg PUR1900 or 200 mg of oral Sporanox (itraconazole oral solution) in a 2-period randomized cross-over design. Itraconazole plasma and sputum concentrations were evaluated.

RESULTS

None of the adverse events considered as at least possibly related to study treatment were moderate or severe, and none were classed as serious. The most common was the infrequent occurrence of mild cough. Itraconazole plasma exposure increased with increasing doses of PUR1900. After 14 days, PUR1900 resulted in plasma exposure (area under the concentration-time curve up to 24 h) 106- to 400-fold lower across doses tested (10-35 mg) than steady-state exposure reported for oral Sporanox 200 mg. In asthmatics, PUR1900 geometric mean maximum sputum concentrations were 70-fold higher and geometric mean plasma concentrations were 66-fold lower than with oral Sporanox.

CONCLUSION

PUR1900 was safe and well-tolerated under the study conditions. Compared to oral dosing, PUR1900 achieved higher lung and lower plasma exposure. The pharmacokinetic profile of PUR1900 suggests the potential to improve upon the efficacy and safety profile observed with oral itraconazole.

The Influence of Different Triazole Antifungal Agents on the Pharmacokinetics of Cyclophosphamide

Background: Cyclophosphamide is one of the most important chemotherapeutic drugs. Known as a widely accepted treatment strategy, chemotherapy may damage the immune function of cancer patients; as a result, invasive fungal infections (IFIs) occur. Triazole antifungal agents are the most acceptable drugs for IFI treatment, especially those infections caused by chemotherapy. Objective: We aimed to investigate the effects of different triazole antifungal drugs, including fluconazole, itraconazole, and ketoconazole, on the pharmacokinetics (PK) of cyclophosphamide. In addition, we also characterize the potential drug-drug interactions (DDIs) between cyclophosphamide and various triazole antifungal drugs. Methods: The necessary pharmacokinetic parameters and physicochemical data were obtained from published studies. Physiologically based pharmacokinetic (PBPK) models were developed and validated in virtual subjects using Simcyp software. The validated PBPK models were used to evaluate potential DDIs between cyclophosphamide and different triazole antifungal agents in cancer patients. Triazole antifungal agents were simulated by oral administration, whereas cyclophosphamide was simulated by intravenous administration. Results: Simulated plasma concentration-time curves of fluconazole, itraconazole, ketoconazole, and cyclophosphamide were in good consistency with the observed profiles. Our results suggested that the pharmacokinetic parameters of cyclophosphamide were increased by various extents when coadministered with different triazole antifungals. The area under the plasma concentration-time curve of cyclophosphamide was increased when combined with fluconazole, itraconazole, or ketoconazole. Conclusions and Relevance: Ketoconazole had the greatest effect on the PK of cyclophosphamide among the 3 triazole antifungals. Our study provides clues that the toxicity and adverse drug reactions that are associated with cyclophosphamide should be closely monitored when coadministered with ketoconazole.

FDA- and EMA-Approved Tyrosine Kinase Inhibitors in Advanced EGFR-Mutated Non-Small Cell Lung Cancer: Safety, Tolerability, Plasma Concentration Monitoring, and Management

Non-small-cell lung cancer (NSCLC) is the most common form of primary lung cancer. The discovery of several oncogenic driver mutations in patients with NSCLC has allowed the development of personalized treatments based on these specific molecular alterations, in particular in the tyrosine kinase (TK) domain of the epidermal growth factor receptor (EGFR) gene. Gefitinib, erlotinib, afatinib, and osimertinib are TK inhibitors (TKIs) that specifically target EGFR and are currently approved by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) as first line treatment for sensitive EGFR-mutant patients. However, these four drugs are associated with severe adverse events (AEs) that can significantly impact patient health-related quality of life and patient monitoring. EGFR-TKIs are commonly used together with other types of medication that can substantially interact. Here, we review approaches used for the management of TKI-AEs in patients with advanced NSCLC to promote the benefits of treatments and minimize the risk of TKI treatment discontinuation. We also consider potential TKI–drug interactions and discuss the usefulness of plasma concentration monitoring TKIs based on chromatographic and mass spectrometry approaches to guide clinical decision-making. Adjusting the most appropriate therapeutic strategies and drug doses may improve the performance therapy and prognosis of patients with advanced EGFR-mutated NSCLC.

Comparative review of drug-drug interactions with epidermal growth factor receptor tyrosine kinase inhibitors for the treatment of non-small-cell lung cancer

The development of small-molecule tyrosine kinase inhibitors (TKIs) that target the epidermal growth factor receptor (EGFR) has revolutionized the management of non-small-cell lung cancer (NSCLC). Because these drugs are commonly used in combination with other types of medication, the risk of clinically significant drug–drug interactions (DDIs) is an important consideration, especially for patients using multiple drugs for coexisting medical conditions. Clinicians need to be aware of the potential for clinically important DDIs when considering therapeutic options for individual patients. In this article, we describe the main mechanisms underlying DDIs with the EGFR-TKIs that are currently approved for the treatment of NSCLC, and, specifically, the potential for interactions mediated via effects on gastrointestinal pH, cytochrome P450-dependent metabolism, uridine diphosphate-glucuronosyltransferase, and transporter proteins. We review evidence of such DDIs with the currently approved EGFR-TKIs (gefitinib, erlotinib, afatinib, osimertinib, and icotinib) and discuss several information sources that are available online to aid clinical decision-making. We conclude by summarizing the most clinically relevant DDIs with these EFGR-TKIs and provide recommendations for managing, minimizing, or avoiding DDIs with the different agents.

Pharmacokinetic Study of Osimertinib in Cancer Patients with Mild or Moderate Hepatic Impairment

Osimertinib, an epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI), undergoes significant hepatic elimination. In this phase 1 study, we assessed the effects of mild and moderate hepatic impairment on the pharmacokinetics (PK) of osimertinib in patients with malignant solid tumors. In part A, patients with normal hepatic function, mild hepatic impairment, and moderate hepatic impairment, according to the Child-Pugh classification, received a single 80 mg oral dose of osimertinib. Standard PK measures were assessed. In part B, patients could continue osimertinib treatment if deemed clinically appropriate. We compared these study results with a population PK analysis including other osimertinib clinical studies. Geometric mean osimertinib plasma concentrations were lower in patients with mild (n = 7) or moderate hepatic impairment (n = 5) versus normal hepatic function (n = 10): C max was reduced to 51% and 61%, respectively; area under the curve was reduced to 63% and 68%, respectively. PK results for the metabolites were similar. No apparent differences in the safety profile were found between patients with normal hepatic function and patients with mild or moderate hepatic impairment. Comparison of these study results with National Cancer Institute-Organ Dysfunction Working Group criteria from population PK analysis showed osimertinib exposure was not affected by hepatic impairment. No dose adjustment is required for osimertinib when treating patients with mild or moderate hepatic impairment. No apparent differences in the safety of osimertinib were found between patients with normal hepatic function and mild or moderate hepatic impairment.

Modulation of Fexofenadine Pharmacokinetics by Osimertinib in Patients With Advanced EGFR-Mutated Non-Small Cell Lung Cancer

Osimertinib is a potent, third-generation, irreversible, central nervous system active epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) that selectively inhibits EGFR-TKI sensitizing and EGFR T790M resistance mutations. It is approved for first-line treatment of patients with advanced non-small cell lung cancer (NSCLC) whose tumors have EGFR exon 19 deletions or exon 21 L858R mutations, and for patients with T790M-positive advanced NSCLC whose disease has progressed on or after EGFR-TKI therapy. This study investigated the pharmacokinetics (PK) of fexofenadine (P-glycoprotein substrate) following single- and multiple-dose osimertinib in patients with advanced NSCLC who have progressed on prior EGFR-TKI therapy. This open-label, phase 1 study (NCT02908750) comprised the PK phase and continued access phase. The former comprised 2 distinct periods with a 3- to 7-day washout: treatment period 1 (n = 24, fexofenadine 120 mg, day 1) and treatment period 2 (fexofenadine 120 mg + osimertinib 80 mg single dose on days 1 and 39 and osimertinib 80 mg once daily from days 4 to 41). Patients could continue osimertinib 80 mg once daily based on investigator's discretion in the continued access phase. Fexofenadine area under the plasma concentration-time curve and maximum concentration increased by 56% (90% confidence interval [CI], 35.4-78.6) and 76% (90%CI, 49.3-108.3) following coadministration with osimertinib single dose, and by 27% (90%CI, 11.2-45.8) and 25% (90%CI, 5.6-48.1) when given with osimertinib at steady state, respectively. Following osimertinib coadministration, median fexofenadine time to maximum concentration increased by approximately 30 minutes compared with time to maximum concentration following fexofenadine alone. No new osimertinib safety findings were observed. The increase in fexofenadine exposure following osimertinib coadministration shows osimertinib as a weak P-glycoprotein inhibitor.

Clinically relevant drug interactions with multikinase inhibitors: a review

Multikinase inhibitors (MKIs), including the tyrosine kinase inhibitors (TKIs), have rapidly become an established factor in daily (hemato)-oncology practice. Although the oral route of administration offers improved flexibility and convenience for the patient, challenges arise in the use of MKIs. As MKIs are prescribed extensively, patients are at increased risk for (severe) drug–drug interactions (DDIs). As a result of these DDIs, plasma pharmacokinetics of MKIs may vary significantly, thereby leading to high interpatient variability and subsequent risk for increased toxicity or a diminished therapeutic outcome. Most clinically relevant DDIs with MKIs concern altered absorption and metabolism. The absorption of MKIs may be decreased by concomitant use of gastric acid-suppressive agents (e.g. proton pump inhibitors) as many kinase inhibitors show pH-dependent solubility. In addition, DDIs concerning drug (uptake and efflux) transporters may be of significant clinical relevance during MKI therapy. Furthermore, since many MKIs are substrates for cytochrome P450 isoenzymes (CYPs), induction or inhibition with strong CYP inhibitors or inducers may lead to significant alterations in MKI exposure. In conclusion, DDIs are of major concern during MKI therapy and need to be monitored closely in clinical practice. Based on the current knowledge and available literature, practical recommendations for management of these DDIs in clinical practice are presented in this review.

The effect of itraconazole and rifampicin on the pharmacokinetics of osimertinib

AIMS

We investigated the effects of a strong CYP3A4 inhibitor (itraconazole) or inducer (rifampicin) on the pharmacokinetics of the epidermal growth factor receptor-tyrosine kinase inhibitor osimertinib, in patients with advanced non-small cell lung cancer in two Phase I, open-label, two-part clinical studies. Part one of both studies is reported.

METHODS

In the itraconazole study (NCT02157883), patients received single-dose osimertinib 80 mg on Days 1 and 10 and itraconazole (200 mg twice daily) on Days 6-18 orally. In the rifampicin study (NCT02197247), patients received osimertinib 80 mg once daily on Days 1-77 and rifampicin 600 mg once daily on Days 29-49.

RESULTS

In the itraconazole study (n = 36), the geometric least squares mean (GMLSM) ratios (osimertinib plus itraconazole/osimertinib alone) for Cmax and AUC were 80% (90% CI 73, 87) and 124% (90% CI 115, 135), respectively, below the predefined no-effect upper limit of 200%. In the rifampicin study (n = 40), the GMLSM ratios (osimertinib plus rifampicin/osimertinib alone) for Css,max and AUCτ were 27% (90% CI 24, 30) and 22% (90% CI 20, 24), respectively, below the predefined no-effect lower limit of 50%. The induction effect of rifampicin was apparent within 7 days of initiation; osimertinib Css,max and AUCτ values returned to pre-rifampicin levels within 3 weeks of rifampicin discontinuation. No new osimertinib safety findings were observed.

CONCLUSIONS

Osimertinib can be co-administered with CYP3A4 inhibitors, but strong CYP3A inducers should be avoided if possible.

Development, Verification, and Prediction of Osimertinib Drug-Drug Interactions Using PBPK Modeling Approach to Inform Drug Label

Osimertinib is a potent, highly selective, irreversible inhibitor of epidermal growth factor receptor (EGFR) and T790M resistance mutation. In vitro metabolism data suggested osimertinib is a substrate of cytochrome P450 (CYP)3A4/5, a weak inducer of CYP3A, and an inhibitor of breast cancer resistance protein (BCRP). A combination of in vitro data, clinical pharmacokinetic data, and drug-drug interaction (DDI) data of osimertinib in oncology patients were used to develop the physiologically based pharmacokinetic (PBPK) model and verify the DDI data of osimertinib. The model predicted the observed monotherapy concentration profile of osimertinib within 1.1-fold, and showed good predictability (within 1.7-fold) to the observed peak plasma concentration (Cmax ) and area under the curve (AUC) DDI ratio changes, when co-administered with rifampicin, itraconazole, and simvastatin, but not with rosuvastatin. Based on observed clinical data and PBPK simulations, the recommended dose of osimertinib when dosed with strong CYP3A inducers is 160 mg once daily. PBPK modeling suggested no dose adjustment with moderate and weak CYP3A inducers.