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This study investigates the biodistribution of a nano lipid carrier system (NLCs) containing the hydrophobic drug erlotinib (ERL-NLCs). The system was labelled with the fluorescent dye IR-780 for real-time dynamic imaging. ERL-NLCs were initially developed using the ultrasonication method with oleic acid and stearic acid. In vitro and ex vivo studies were performed to confirm the formation and penetration of NLCs within the intestine. Subsequently, the biological distribution of ERL-NLCs was monitored using a fluorescent dye through the IVIS® fluorescent optical imaging technique in whole live animals. Mice were orally administered blank IR 780 dye solution, ERL suspension, and IR 780 labelled NLCs. Fluorescence images were acquired at different time intervals up to 24 h and then total radiant efficiency was calculated through the region of interest (ROI) of the whole animal at each interval of time for all three groups. To validate the results obtained from in vivo imaging, various organs including lungs, heart, liver, both kidneys, stomach, and intestine were subsequently extracted and examined after 24 h. The ROI was found to be higher in the blank IR 780 dye solution, followed by the drug suspension and IR 780 labelled NLCs. These results confirm that the plain ERL suspension distributes across the body, and its encapsulation in NLCs facilitates passage through the lymphatic intestinal pathway, effectively avoiding first-pass metabolism. The remarkable results indicated that the NLCs formulation effectively circumvents first-pass metabolism by adopting the intestinal lymphatic pathway, thereby enhancing the oral bioavailability of the drug. This observed behaviour underscores the potential of NLCs in optimizing drug delivery and minimizing adverse effects associated with gastrointestinal and metabolic processes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Aims: The aim of the study is to report the clinical and pharmacological observations from a pregnant patient treated with erlotinib in the second and third trimesters of pregnancy., Methods: Maternal and neonatal blood levels and safety of erlotinib and its metabolites were evaluated. Child development was monitored for 6 years., Results: A 31-year-old woman with stage IV lung adenocarcinoma with EGFR exon19 deletion began treatment with erlotinib 150 mg/day at 17 weeks of gestation. Although foetal growth retardation and oligohydramnios were observed at several times during the pregnancy, treatment was continued due to the severity of the maternal presentation, with ongoing foetal monitoring. The foetus seemed to tolerate and recover well without specific interventions. A healthy baby boy was delivered at 37 weeks gestation. The child grew and developed without any obvious issues. At last follow-up, at age 6 years, he was attending school at a grade appropriate for his age without health or developmental problems. Blood levels of erlotinib were 397-856 ng/mL at 18-37 weeks of gestation and 1190 ng/mL at 8 weeks postpartum. The blood concentration ratios of OSI-413-to-erlotinib ranged from 0.167 to 0.253 at 18-37 weeks of gestation, excluding 24 weeks, and 0.131 at 8 weeks postpartum. The maternal-to-foetal transfer rate of erlotinib, OSI-420 and OSI-413 were 24.5, 34.8 and 20.3%, respectively., Conclusion: Erlotinib use during the second and third trimester of pregnancy did not seem to cause any untoward effects on the developing foetus, or any long-lasting effects that could be detected during 6 years of follow-up of the child., (© 2024 British Pharmacological Society.)

The propensity for aldehyde oxidase (AO) substrates to be implicated in drug-drug interactions (DDIs) is not well understood due to the dearth of potent inhibitors that elicit in vivo inhibition of AO. Although there is only one reported instance of DDI that has been ascribed to the inhibition of AO to date, the supporting evidence for this clinical interaction is rather tenuous, and its veracity has been called into question. Our group recently reported that the epidermal growth factor receptor inhibitor erlotinib engendered potent time-dependent inhibition of AO with inactivation kinetic constants in the same order of magnitude as its free circulating plasma concentrations. At the same time, it was previously reported that the concomitant administration of erlotinib with the investigational drug OSI-930 culminated in a an approximately twofold increase in its systemic exposure. Although the basis underpinning this interaction remains unclear, the structure of OSI-930 contains a quinoline motif that is amenable to oxidation at the electrophilic carbon adjacent to the nitrogen atom by molybdenum-containing hydroxylases like AO. In this study, we conducted metabolite identification that revealed that OSI-930 undergoes AO metabolism to a mono-oxygenated 2-oxo metabolite and assessed its formation kinetics in human liver cytosol. Additionally, reaction phenotyping in human hepatocytes revealed that AO contributes nearly 50% to the overall metabolism of OSI-930. Finally, modeling the interaction between erlotinib and OSI-930 using a mechanistic static model projected an ∼1.85-fold increase in the systemic exposure of OSI-930, which accurately recapitulated clinical observations. SIGNIFICANCE STATEMENT: This study delineates an aldehyde oxidase (AO) metabolic pathway in the investigational drug OSI-930 for the first time and confirmed that it represented a major route of metabolism through reaction phenotyping in human hepatocytes. Our study provided compelling mechanistic and modeling evidence for the first instance of an AO-mediated clinical drug-drug interaction stemming from the in vivo inhibition of the AO-mediated quinoline 2-oxidation pathway in OSI-930 by erlotinib., (Copyright © 2024 by The American Society for Pharmacology and Experimental Therapeutics.)

The goal of the study was to fabricate folic acid functionalized docetaxel (DOC)/erlotinib (ERL)-loaded solid lipid nanoparticles (SLNs) to synergistically increase the anticancer activity against triple-negative breast cancer. DOC/ERL-SLNs were prepared by the high shear homogenization - ultrasound dispersion method (0.1 % w/v for DOC, and 0.3 %w/v for ERL) and optimized using Plackett Burman Design (PBD) followed by Box Behnken Design (BBD). The optimized SLNs demonstrated particle size < 200 nm, PDI < 0.35, and negative zeta potential with entrapment and loading efficiency of ∼80 and ∼4 %, respectively. The SLNs and folic acid functionalized SLNs (FA-SLNs) showed sustained release for both drugs, followed by Higuchi and Korsemeyer-Peppas drug release models, respectively. Further, the in vitro pH-stat lipolysis model demonstrated an approximately 3-fold increase in the bioaccessibility of drugs from SLNs compared to suspension. The TEM images revealed the spherical morphology of the SLNs. DOC/ERL loaded SLNs showed dose- and time-dependent cytotoxicity and exhibited a synergism at a molar ratio of 1:3 in TNBC with a combination index of 0.35 and 0.37, respectively. FA-DOC/ERL-SLNs showed enhanced anticancer activity as evidenced by MMP and ROS assay and further inhibited the colony-forming ability and the migration capacity of TNBC cells. Conclusively, the study has shown that SLNs are encouraging systems to improve the pharmaceutical attributes of poorly bioavailable drugs., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Insight into the development of treatment resistance can support the optimization of anticancer treatments. This study aims to characterize the tumor dynamics and development of drug resistance in patients with non-small cell lung cancer treated with erlotinib, and investigate the relationship between baseline circulating tumor DNA (ctDNA) data and tumor dynamics. Data obtained for the analysis included (1) intensively sampled erlotinib concentrations from 29 patients from two previous pharmacokinetic (PK) studies, and (2) tumor sizes, ctDNA measurements, and sparsely sampled erlotinib concentrations from 18 patients from the START-TKI study. A two-compartment population PK model was first developed which well-described the PK data. The PK model was subsequently applied to investigate the exposure-tumor dynamics relationship. To characterize the tumor dynamics, models accounting for intra-tumor heterogeneity and acquired resistance with or without primary resistance were investigated. Eventually, the model assumed acquired resistance only resulted in an adequate fit. Additionally, models with or without exposure-dependent treatment effect were explored, and no significant exposure-response relationship for erlotinib was identified within the observed exposure range. Subsequently, the correlation of baseline ctDNA data on EGFR and TP53 variants with tumor dynamics' parameters was explored. The analysis indicated that higher baseline plasma EGFR mutation levels correlated with increased tumor growth rates, and the inclusion of ctDNA measurements improved model fit. This result suggests that quantitative ctDNA measurements at baseline have the potential to be a predictor of anticancer treatment response. The developed model can potentially be applied to design optimal treatment regimens that better overcome resistance., (© 2024 The Authors. CPT: Pharmacometrics & Systems Pharmacology published by Wiley Periodicals LLC on behalf of American Society for Clinical Pharmacology and Therapeutics.)

Background: Combination therapy using more than one drug can result in a synergetic effect in clinical treatment of cancer. For this, it is important to develop an efficient drug delivery system that can contain multiple drugs and provide high accumulation in tumor tissue. In particular, simultaneous and stable loading of drugs with different chemical properties into a single nanoparticle carrier is a difficult problem., Results: We developed rhamnolipid-coated double emulsion nanoparticles containing doxorubicin and erlotinib (RL-NP-DOX-ERL) for efficient drug delivery to tumor tissue and combination chemotherapy. The double emulsion method enabled simultaneous loading of hydrophilic DOX and hydrophobic ERL in the NPs, and biosurfactant RL provided stable surface coating. The resulting NPs showed fast cellular uptake and synergetic tumor cell killing in SCC7 cells. In real-time imaging, they showed high accumulation in SCC7 tumor tissue in mice after intravenous injection. Furthermore, enhanced tumor suppression was observed by RL-NP-DOX-ERL in the same mouse model compared to control groups using free drugs and NPs containing a single drug., Conclusions: The developed RL-NP-DOX-ERL provided efficient delivery of DOX and ERL to tumor tissue and successful tumor therapy with a synergetic effect. Importantly, this study demonstrated the promising potential of double-emulsion NPs and RL coating for combination therapy., (© 2021. The Author(s).)

Abstract: We describe a clinical case of an 84-year-old man diagnosed with non-small cell lung carcinoma and epidermal growth factor receptor mutation, who was treated with erlotinib, with doses adjusted by therapeutic drug monitoring. This case involved a clearance fluctuation leading to over-therapeutic drug concentrations of erlotinib and toxicity. The intrapatient and interpatient variability of erlotinib, in addition to other factors such as age or variations in liver clearance, create situations that are challenging in clinical practice. During treatment, erlotinib serum concentrations were measured, and the dose was accordingly adjusted. The erlotinib dose required to reduce toxicity (rash grade III) and maintain effective plasma concentrations, as well as clinical and radiological responses, was 50% of the initial dose, underscoring the relevance of therapeutic drug monitoring for tyrosine kinase inhibitors in routine clinical practice., Competing Interests: The authors declare no conflict of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

The aim of our study was to investigate the effects of single-dose Ougan (Citrus reticulata cv. Suavissima) juice application on the pharmacokinetics of erlotinib in vivo. Twelve Sprague-Dawley rats were randomly divided into the Ougan juice and control groups ( n = 6 each). The rats were given a single dose of 1 mL/100 g Ougan juice or 1 mL/100 g normal saline (NS) by intragastric administration, followed by a single oral administration of 20 mg/kg erlotinib. The plasma concentration of erlotinib in rats was determined using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Erlotinib-d6 was used as the internal standard for chromatographic analysis on the UPLC BEH C18 analysis column (2.1 mm × 50 mm, 1.7  μ m). The mobile phase was composed of acetonitrile and 0.1% formic acid eluting by gradient. Different pharmacokinetic (PK) parameters of erlotinib were calculated. The Ougan juice promoted the absorption of erlotinib and reduced the clearance of the drug. The area under the curve of erlotinib in the single-dose Ougan juice pretreatment group was approximately 1.87 times higher, and the maximum blood concentration (Cmax) was approximately 1.34 times higher than that in the control group. The mean residence time of erlotinib in the Ougan juice group was larger, and the clearance rate was smaller than those in the control group; the difference was statistically significant ( P < 0.05). Ougan juice affected the PK spectrum of erlotinib in rats by improving the bioavailability of the drug and significantly increasing its plasma concentration., Competing Interests: The author(s) declare(s) that there is no conflict of interest regarding the publication of this paper., (Copyright © 2021 Jin-zhao Yang et al.)

Erlotinib (ERL), a tyrosine kinase inhibitor approved for therapeutic use in non-small cell lung cancer is further researched for eventual liver cancer treatment. However, conventional ERL has important bioavailability problems resulting from oral administration, poor solubility and gastrointestinal degradation into inactive metabolites. Alternative administration routes and nanoparticulate drug delivery systems are studied to prevent or reduce these drawbacks. In this study, ERL-loaded CD nanosphere and nanocapsule formulations capable of cholesterol depletion in resistant cancer cells were evaluated for ERL delivery. Drug loading and release profile depended largely on the surface charge of nanoparticles. Antiproliferative activity data obtained from 2D and 3D cell culture models demonstrated that polycationic βCD nanocapsules were the most effective formulation for ERL delivery to lung and liver cancer cells. 3D tumour tumoral penetration studies further revealed that nanocapsule formulations penetrated deeper into the tumour through the multilayered cells. Furthermore, all formulations were able to extract membrane cholesterol from lung and liver cancer cell lines, indicating the induction of apoptosis and overcoming drug resistance. In conclusion, given their tumoral penetration and cell membrane cholesterol depletion abilities, amphiphilic CD nanocapsules emerge as promising alternatives to improve the safety and efficiency of ERL treatment of both liver and lung tumours.

Background Amrubicin (AMR) is a completely synthetic 9-aminoanthracycline and clinically active against non-small cell lung cancer (NSCLC). We conducted a phase I study of AMR and erlotinib (ERL) combination therapy in previously treated patients with advanced NSCLC and have already reported the safety and effectiveness. Methods We conducted a multi-center, single-arm phase II trial to evaluate the efficacy of AMR and ERL combination therapy in patients with previously treated, advanced NSCLC harboring wild-type EGFR, PS 0-1 and < 75 years of age. Patients were treated at 3-week intervals with AMR plus ERL. The primary endpoint was the PFS, and the secondary endpoints were the response rate (RR), disease control rate (DCR), overall survival (OS) and toxicity. The trough ERL concentration (C trough ) was measured as an exploratory study to analyze the relationship between the efficacy/safety and pharmacokinetics. Results From June 2013 to July 2016, 25 patients were enrolled in this trial. The PFS according to the central test was 3.6 months (95% confidence interval 2.1-5.1). The RR and DCR were 24.0% and 64.0%, respectively. We had no treatment-related deaths in this study. Conclusions The PFS of AMR and ERL combination therapy was superior to that of AMR monotherapy in the historical setting, but the primary endpoint was not met in this trial. In our study, the pharmacokinetic analysis showed that the C trough of ERL was elevated with combination therapy. This combination therapy might be a viable treatment for previously treated NSCLC patients without a driver oncogene mutation. Clinical trial information UMIN 000010582.

A randomized, open-label, 2-period crossover study was performed to evaluate the pharmacokinetic properties and bioequivalence of 2 erlotinib hydrochloride tablets (a test formulation and a reference formulation) in healthy Chinese subjects. Subjects were randomized to receive a single oral dose of the erlotinib hydrochloride test or reference formulation (150 mg) under fasting conditions. The washout period was 12 days. Blood samples were collected at scheduled time points, and plasma concentrations were determined using a high-performance liquid chromatography-tandem mass spectrometry method. A noncompartmental method was used to calculate pharmacokinetic parameters and to evaluate the bioequivalence of the 2 formulations. Safety assessments were performed during the whole study period. The results suggest that the pharmacokinetic parameter values of the test formulation were similar to those of the reference formulation. The 90% confidence intervals of the geometric least-squares mean ratios of the test to reference formulation were 94.06% to 105.43% for maximum concentration, 88.21% to 97.57% for area under the concentration-time curve to last measurement, and 87.37% to 97.14% for area under the curve extrapolated to infinity, which are all within the accepted bioequivalence range of 80% to 125%. No serious adverse events occurred during the study. These findings suggest that the 2 erlotinib hydrochloride tablets were bioequivalent in accordance with predetermined regulatory criteria., (© 2020, The American College of Clinical Pharmacology.)

The recommended daily dose of erlotinib was determined for patients with all types of non-small cell lung cancer (NSCLC). We determined the optimal dose (OD) in patients with NSCLC harboring only epidermal growth factor receptor (EGFR) sensitizing mutations. EGFR-tyrosine kinase inhibitor-naïve patients with sensitizing mutations were eligible. Clinical OD was determined in a phase I/II study based on the continual re-assessment method (CRM) of both disease control and dose-limiting toxicity, defined as any toxicity of grade 2 (G2) or higher within 8 weeks. We also determined the pharmacologic OD via a pharmacokinetic (PK) study. Thirty-eight patients were enrolled. Clinical OD was 25 mg/day by the CRM. Median progression-free survival (mPFS) was 9.3 months. In receiver operating characteristic (ROC) analysis of mPFS, the trough concentration ( C min ss ) was ≥ 0.30 μg/mL. The area under the curve (AUC) and C min ss were predicted via population PK (PopPK) or a bootstrap of 100 iterations (PopPK 100 ). TOX20 was defined as < 20% duration of any toxicity ≥ G2 during the PFS period. In ROC analysis of mPFS and TOX20 in the PopPK 100 study, C min ss was ≥ 0.17 and < 0.32 μg/mL, respectively. In ROC analysis of mPFS and TOX20 in the PopPK 100 study, C min ss was ≥ 0.15 and < 0.31 μg/mL, AUC was ≥ 14.4 and < 14.5 μg/mL•hour, and the dosage was ≥ 58.4 and < 58.8 mg/day, respectively. Clinical and pharmacologic ODs were 25 by CRM and 50-60 mg/day by PK, respectively. The proposed starting OD is 50-60 mg/day, with personalized adjustment of 0.15-0.31 μg/mL based on C min ss as determined by PopPK monitoring., (© 2020 The Authors. Clinical and Translational Science published by Wiley Periodicals, Inc. on behalf of the American Society for Clinical Pharmacology and Therapeutics.)

Introduction: Nasopharyngeal carcinoma (NPC) is a common cancer in southern China and Taiwan, and radiation therapy combined with or without chemotherapy is its mainstay treatment. Although it is highly sensitive to radiotherapy, local recurrence and distant metastasis remain difficult unsolved problems. In recent years, graphene oxide (GO) has been found to be a promising novel anticancer drug carrier. Here, we present our designed functionalized GO, polyethylene glycol-coated GO (GO-PEG), as a drug carrier, which was loaded with erlotinib and showed promising anticancer effects on NPC cells., Methods: The effects of GO-PEG-erlotinib on the proliferation, migration, and invasion of NPC cells were investigated by WST-8 assay, wound healing assay, and invasion assay, respectively. RNA sequencing was conducted and analyzed to determine the molecular mechanisms by which GO-PEG-erlotinib affects NPC cells., Results: Our results showed that GO-PEG-erlotinib reduced NPC cell viability in a dose-dependent manner and also inhibited the migration and invasion of NPC cells. The RNA sequencing revealed several related molecular mechanisms., Conclusion: GO-PEG-erlotinib effectively suppressed NPC cell proliferation, migration, and invasion, likely by several mechanisms. GO-PEG-erlotinib may be a potential therapeutic agent for treating NPC in the future., Competing Interests: The authors report no conflicts of interest for this work., (© 2020 Lan et al.)

Purpose: Patients of non-small cell lung cancer (NSCLC) with brain metastases have limited treatment options. High-dose erlotinib (HDE) and gefitinib (HDG) have been tried in the past. This study investigates the cerebrospinal fluid (CSF) disposition and safety of both, high-dose erlotinib and gefitinib regimens., Methods: Eleven and nine patients were treated with erlotinib and gefitinib, respectively. All patients received 1 week of standard dose of erlotinib (150 mg OD) or gefitinib (250 mg OD), followed by the high dose (1500 mg weekly for erlotinib and 1250 mg OD for gefitinib) from day 8. Blood and CSF samples were collected on days 7 and 15, 4 h after the morning dose and drug levels determined using LC-MS/MS. Adverse events were documented as per CTCAE 4.03 till day 15., Results: Pulsatile HDE and daily HDG resulted in 1.4- and 1.9-fold increase in CSF levels, respectively. A constant 2% CSF penetration rate was observed across both doses of erlotinib, while for gefitinib the penetration rate for high dose was half that of the standard dose suggesting a nonlinear disposition. Three patients on HDE treatment discontinued treatment after the first dose due to intolerable toxicities, whereas HDG was better tolerated with no treatment discontinuations. Since CSF disposition of gefitinib followed saturable kinetics, a lower dose of 750 mg was found to achieve CSF concentrations comparable to that of the 1250 mg dose., Conclusions: HDG was better tolerated than HDE. CSF disposition of gefitinib was found to be saturable at a higher dose. Based on these findings, the dose of 750 mg OD should be considered for further evaluation in this setting.

Identification of optimal schedules for combination drug administration relies on accurately estimating the correct pharmacokinetics, pharmacodynamics, and drug interaction effects. Misspecification of pharmacokinetics can lead to wrongly predicted timing or order of treatments, leading to schedules recommended on the basis of incorrect assumptions about absorption and elimination of a drug and its effect on tumor growth. Here, we developed a computational modeling platform and software package for combination treatment strategies with flexible pharmacokinetic profiles and multidrug interaction curves that are estimated from data. The software can be used to compare prespecified schedules on the basis of the number of resistant cells where drug interactions and pharmacokinetic curves can be estimated from user-provided data or models. We applied our approach to publicly available in vitro data of treatment with different tyrosine kinase inhibitors of BT-20 triple-negative breast cancer cells and of treatment with erlotinib of PC-9 non-small cell lung cancer cells. Our approach is publicly available in the form of an R package called ACESO (https://github.com/Michorlab/aceso) and can be used to investigate optimum dosing for any combination treatment. SIGNIFICANCE: These findings introduce a computational modeling platform and software package for combination treatment strategies with flexible pharmacokinetic profiles and multidrug interaction curves that are estimated from data., (©2020 American Association for Cancer Research.)

Purpose: Erlotinib is an oral first-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor approved for non-small cell lung cancers (NSCLC) with EGFR-activating mutations. Older patients experience more toxicities compared with younger patients at the standard recommended dose of 150 mg once daily. The aims of this study were to describe the pharmacokinetic profile of erlotinib in unselected patients with NSCLC, to quantify and explain its variability, to challenge the standard recommended dose in older patients, and to propose clinical recommendations for the therapeutic management of patients taking erlotinib., Methods: A population pharmacokinetic model was developed using erlotinib plasma concentrations collected from patients with NSCLC participating in a routine therapeutic drug monitoring program (with the nonlinear mixed effect modeling program NONMEM). Relevant demographic characteristics, clinical factors, and co-medications were tested as potential covariates. An independent dataset was used for model validation. Simulations based on the final model allowed comparison of expected erlotinib concentrations under standard and alternative dosing regimens for smokers and for several age groups., Findings: A total of 481 erlotinib plasma concentrations from 91 patients with NSCLC were used for model building and 239 plasma drug concentrations from 107 patients for model validation. A one-compartment model with first-order absorption and elimination provided the best fit. Average erlotinib CL/F with interindividual variability (%CV) was 3.8 L/h (41.5%), and V/F was 166 L (53.8%). The absorption rate constant was 1.48 h -1 . The external validation showed a negligible bias of -4% (95% CI, -7 to -1) in the individual predictions, with a precision of 23%. Current smoking and use of proton pump inhibitors were associated with higher CL/F, whereas age was associated with lower CL/F. Simulations suggest that a lower dose in older patients would decrease the risk of overexposure., Implications: This large cohort study confirms the substantial interindividual variability in erlotinib plasma exposure and the impact of smoking and proton pump inhibitor intake. This large variability in erlotinib pharmacokinetics indicates that the standard recommended dose of 150 mg once daily is likely not appropriate to reach the expected concentrations in each patient. Concentration monitoring should be performed to individually adjust the erlotinib dosing regimen. The observed decrease in erlotinib CL/F with age suggests that a lower starting daily dose of 100 mg with concentration-guided dose adjustment would prevent overexposure and potential toxicity in older frail patients with co-morbidities., (Copyright © 2020. Published by Elsevier Inc.)

Importance: Although the efficacy of epidermal growth factor receptor tyrosine kinase inhibitors for EGFR gene mutation-positive non-small cell lung cancer is well established, optimal dosing remains to be established, especially in elderly or frail patients., Objective: To investigate the efficacy and safety of low-dose erlotinib in elderly or frail patients with EGFR mutation-positive non-small cell lung cancer., Design, Setting, and Participants: Single-arm phase 2 trial with the Southwest Oncology Group (SWOG) 2-stage design that enrolled frail patients from 21 Japanese institutions after meeting the inclusion criteria. Chemotherapy-naive patients with EGFR-activating mutation-positive non-small cell lung cancer who were considered frail based on age, the Charlson Comorbidity Index, and Eastern Cooperative Oncology Group performance status were eligible for the study., Interventions: Patients were initially administered 50 mg/d erlotinib for 4 weeks, which was modified based on response or adverse events. Dose increase was permitted for patients with stable disease after 4 weeks., Main Outcomes and Measures: The primary end point was the independent review committee-confirmed objective response rate (ORR) at the dose of 50 mg/d. The study also evaluated the pharmacokinetics of low-dose erlotinib and influence of ABCB1 gene polymorphisms., Results: Eighty patients were enrolled, with a median (range) age of 80 (49-90) years; 54 (68%) were men. An independent review committee confirmed a significant ORR of 60.0% (90% CI, 50.2%-69.2%). The disease control rate was 90.0% (90% CI, 82.7%-94.9%), median progression-free survival was 9.3 months (95% CI, 7.2-11.4 months), and median overall survival was 26.2 months (95% CI, 21.9-30.4 months). Mild adverse events were observed in some participants, with few patients exhibiting grade 3 or greater adverse events. Low-dose erlotinib treatment was temporarily suspended for 10 patients owing to adverse events. Five of 80 patients (6%) had their erlotinib dose reduced to 25 mg because of oral mucositis, paronychia, erythema multiforme, diarrhea, and anorexia. Two patients discontinued treatment because of adverse events (cutaneous ulcer and bone infection, and oral mucositis, respectively). There were no cases of interstitial lung disease or treatment-related deaths. The median (range) erlotinib plasma concentration was measured at 685 (153-1950) ng/mL. Seventy-three patients discontinued study treatment owing to disease progression (n = 60), death (n = 3), AEs (n = 4), and patient requests (n = 6). No clear association was observed between the pharmacokinetics of low-dose erlotinib and the treatment outcome., Conclusions and Relevance: Low-dose erlotinib appears to be safe and effective in elderly or frail patients with EGFR mutation-positive non-small cell lung cancer and can be a valid treatment option., Trial Registration: UMIN-CTR Identifier: UMIN000015949.

Combination therapy has emerged as an efficient way to deliver chemotherapeutics for treatment of glioblastoma. It provides collaborative approach of targeting cancer cells by acting via multiple mechanisms, thereby reducing drug resistance. However, the presence of impermeable blood brain barrier (BBB) restricts the delivery of chemotherapeutic drugs into the brain. To overcome this limitation, we designed a dual functionalized liposomes by modifying their surface with transferrin (Tf) and a cell penetrating peptide (CPP) for receptor and adsorptive mediated transcytosis, respectively. In this study, we used two different CPPs (based on physicochemical properties) and investigated the influence of insertion of CPP to Tf-liposomes on biocompatibility, cellular uptake, and transport across the BBB both in vitro and in vivo. The biodistribution profile of Tf-CPP liposomes showed more than 10 and 2.7 fold increase in doxorubicin and erlotinib accumulation in mice brain, respectively as compared to free drugs with no signs of toxicity., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Iced teas (ITs), also known as ready-to-drink teas, have gained much popularity among many nations. The modulatory effect of tea beverages on CYP3A4 increases the possibility of their potential interactions with many coadministered medications. Being a substrate of CYP3A4, sorafenib (SOR), the first-line therapy for the treatment of hepatocellular carcinoma, shows a great probability to exhibit pharmacokinetic (PK) interaction with ITs. For this purpose, different groups of Wistar rats were given oral doses of SOR (40 mg/kg), along with different types of ITs. The concentration of SOR in rat plasma was determined using UPLC-MS/MS. Chromatographic analysis was performed on a C18 analytical column, Acquity UPLC BEH™ (100 × 1.0 mm, i.d., 1.7  μ m particle size), using erlotinib (ERL) as an internal standard. Isocratic elution was performed with a mobile phase consisting of two solvents: solvent A (water with 0.1% formic acid) and solvent B (acetonitrile with 0.1% formic acid), in a ratio of 30 : 70, v/v, respectively. Quantitation was performed using MRM of the transitions from protonated precursor ions [M+H] + to product ions at m/z 465.12 > 252.02 (SOR) and m/z 394.29 > 278.19 (ERL). The method was fully validated as per the FDA guidance for bioanalytical method validation in the concentration range of 2.5-500 ng/mL. Different PK parameters were calculated for SOR in all rat groups and groups administered with ITs and SOR, compared with groups with simply water and SOR. Experimental data revealed that ITs caused a general reduction in SOR bioavailability; an approximate reduction of 30% was recorded for all types of tested ITs. These data indicate that ITs could affect the PK profile of SOR in rats., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2019 Hadir M. Maher et al.)

Purpose: Erlotinib (Tarceva ® ), a potent small molecule inhibitor of the epidermal growth factor receptor tyrosine kinase, has been evaluated to treat infants and children with primary brain tumors. The pharmacokinetics of erlotinib and its primary metabolite OSI-420 were characterized and exposure-safety associations were investigated., Methods: This analysis involved patients enrolled in two clinical studies and receiving oral erlotinib once daily as part of treatment. Single-dose and steady-state erlotinib and OSI-420 plasma concentrations were assayed using HPLC-MS/MS methods. Population pharmacokinetic modeling and univariate covariate analysis evaluating demographic, clinical and selected CYP3A5, CYP3A4, ABCB1, and ABCG2 genotypes were performed. Associations between erlotinib and OSI-420 pharmacokinetics, and with toxicities (diarrhea and skin rash) occurring post-dose were explored., Results: Data from 47 patients (0.7-19 years old) were collected and best fitted by one-compartment linear models. Erlotinib and OSI-420 apparent clearances (CL/F and CL m /F m ) were higher in patients < 5 years compared to older patients (mean CL/F: 6.8 vs 3.6 L/h/m 2 , and mean CL m /F m : 79 vs 38 L/h/m 2 , p < 0.001), and were 1.62-fold and 1.73-fold higher in males compared to females (p < 0.01). Moreover, CL/F was 1.53-fold higher in wild-type patients than in patients heterozygous or homozygous mutant for ABCG2 rs55930652 (p < 0.05). Most of the toxicities reported were grade 1. No associations were found between drug pharmacokinetics and drug-induced toxicities., Conclusions: Erlotinib therapy was well tolerated by pediatric patients with primary brain tumors. No dosing adjustments based on age or patient characteristics are recommended for this patient population.

Glioblastoma is a hostile brain tumor associated with high infiltration leading to poor prognosis. Anti-cancer chemotherapeutic agents have limited access into the brain due to the presence of the blood brain barrier (BBB). In this study, we designed a dual functionalized liposomal delivery system, surface modified with transferrin (Tf) for receptor mediated transcytosis and a cell penetrating peptide-penetratin (Pen) for enhanced cell penetration. We loaded doxorubicin and erlotinib into liposomes to enhance their translocation across the BBB to glioblastoma tumor. In vitro cytotoxicity and hemocompatibility studies demonstrated excellent biocompatibility for in vivo administration. Co-delivery of doxorubicin and erlotinib loaded Tf-Pen liposomes revealed significantly (p < 0.05) higher translocation (~15%) across the co-culture endothelial barrier resulting in regression of tumor in the in vitro brain tumor model. The biodistribution of Tf-Pen liposomes demonstrated ~12 and 3.3 fold increase in doxorubicin and erlotinib accumulation in mice brain, respectively compared to free drugs. In addition, Tf-Pen liposomes showed excellent antitumor efficacy by regressing ~90% of tumor in mice brain with significant increase in the median survival time (36 days) along with no toxicity. Thus, we believe that this study would have high impact for treating patients with glioblastoma., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Aims: Erlotinib is a tyrosine kinase inhibitor used in the treatment of non-small cell lung cancer highly metabolized by the cytochrome P450 (CYP) 3A. Hence, CYP3A4 activity might be a useful predictor of erlotinib pharmacokinetics in personalized medicine. The effect of erlotinib on CYP3A activity was therefore studied in non-small cell lung cancer patients., Methods: The study included 32 patients scheduled for erlotinib monotherapy. CYP3A activity was assessed using quinine as a probe before and during erlotinib treatment. Plasma from blood samples drawn 16 hours post quinine administration were analysed using HPLC with fluorescence detection to determine the quinine/3-OH-quinine ratio., Results: Matched samples, available from 13 patients, showed an induction of CYP3A activity (P = 0.003, Wilcoxon's signed rank test) after 2 months of treatment. The quinine/3-OH-quinine ratio decreased from 20.2 (± 13.4) at baseline to 11.0 (± 4.34). Single-point samples, available from 19 patients, supported the decrease in ratio (P = 0.007, Mann-Whitney U-test). Generally, females had a higher CYP3A activity both at baseline and after two months of treatment. Statistical analysis by gender also showed significant increase in CYP3A activity (males, n = 10, P = 0.001, and females, n = 22, P = 0.001)., Conclusions: An induction of CYP3A activity was observed after 2 months of erlotinib treatment which was also seen when subdividing based on gender. It could be important to take this into consideration for patients co-administering other CYP3A-metabolizing drugs during erlotinib treatment and also makes it difficult to use baseline CYP3A activity to predict erlotinib pharmacokinetics., (© 2019 The British Pharmacological Society.)

Positron emission tomography (PET) imaging with radiolabeled drugs holds great promise to assess the influence of membrane transporters on hepatobiliary clearance of drugs. To exploit the full potential of PET, quantitative pharmacokinetic models are required. In this study, we evaluated the suitability of different compartment models to describe the hepatic disposition of [ 11 C]erlotinib as a small-molecule model drug which undergoes transporter-mediated hepatobiliary excretion. We analyzed two different, previously published data sets in healthy volunteers, in which a baseline [ 11 C]erlotinib PET scan was followed by a second PET scan either after oral intake of unlabeled erlotinib (300 mg) or after intravenous infusion of the prototypical organic anion-transporting polypeptide inhibitor rifampicin (600 mg). We assessed a three-compartment (3C) and a four-compartment (4C) model, in which either a sampled arterial blood input function or a mathematically derived dual input function (DIF), which takes the contribution of the portal vein to the liver blood supply into account, was used. Both models provided acceptable fits of the observed PET data in the liver and extrahepatic bile duct and gall bladder. Changes in model outcome parameters between scans were consistent with the involvement of basolateral hepatocyte uptake and canalicular efflux transporters in the hepatobiliary clearance of [ 11 C]erlotinib. Our results demonstrated that inclusion of a DIF did not lead to substantial improvements in model fits. The models developed in this work represent a step forward in applying PET as a tool to assess the impact of hepatic transporters on drug disposition and their involvement in drug-drug interactions.

The adenosine triphosphate-binding cassette transporters P-glycoprotein (ABCB1) and breast cancer resistance protein (ABCG2) are 2 efflux transporters at the blood-brain barrier (BBB) that effectively restrict brain distribution of dual ABCB1/ABCG2 substrate drugs, such as tyrosine kinase inhibitors. Pharmacologic inhibition of ABCB1/ABCG2 may improve the efficacy of dual-substrate drugs for treatment of brain tumors, but no marketed ABCB1/ABCG2 inhibitors are currently available. In the present study, we examined the potential of supratherapeutic-dose oral erlotinib to inhibit ABCB1/ABCG2 activity at the human BBB. Methods : Healthy men underwent 2 consecutive PET scans with 11 C-erlotinib: a baseline scan and a second scan either with concurrent intravenous infusion of the ABCB1 inhibitor tariquidar (3.75 mg/min, n = 5) or after oral intake of single ascending doses of erlotinib (300 mg, n = 7; 650 mg, n = 8; or 1,000 mg, n = 2). Results : Although tariquidar administration had no effect on 11 C-erlotinib brain distribution, oral erlotinib led, at the 650-mg dose, to significant increases in volume of distribution (23% ± 13%, P = 0.008), influx rate constant of radioactivity from plasma into brain (58% ± 26%, P = 0.008), and area under the brain time-activity curve (78% ± 17%, P = 0.008), presumably because of combined partial saturation of ABCG2 and ABCB1 activity. Inclusion of further subjects into the 1,000-mg dose group was precluded by adverse skin events (rash). Conclusion : Supratherapeutic-dose erlotinib may be used to enhance brain delivery of ABCB1/ABCG2 substrate anticancer drugs, but its clinical applicability for continuous ABCB1/ABCG2 inhibition at the BBB may be limited by safety concerns., (© 2019 by the Society of Nuclear Medicine and Molecular Imaging.)

Lung cancer patients develop acquired resistance to tyrosine kinase inhibitors including erlotinib (ERL) after few months of primary treatment. Evidently, new chemotherapy strategies to delay or overcome the resistance are urgently needed to improve the clinical outcome in non-small cell lung cancer (NSCLC) patients. In this paper, we have investigated the cytotoxic interaction of ERL and valproic acid (VA) in ERL-resistant NSCLC cells and developed a liquisolid formulation of ERL-VA for improving oral bioavailability of ERL. ERL is weakly basic, biopharmaceutical classification system (BCS) class II drug with extremely poor aqueous solubility while VA is a branched chain fatty acid. Ionic interaction between ERL and VA (1:2 M ratio) resulted in significant enhancement in saturation solubility of ERL at different pH range. Liquisolid formulation of ERL-VA (EVLF) developed using PEG 400 and mesoporous calcium silicate was characterized for solid state and in vitro dissolution in biorelevant dissolution medium (FaSSIF and FeSSIF). Cytotoxicity of ERL was enhanced by 2-5 folds on co-incubation with VA in HCC827/ERL cell line. Flow cytometry analysis using AnnexinV-FITC assay demonstrated that VA and ERL alone have poor apoptotic effect on HCC827/ERL cells while combination showed around 69% apoptotic cells. Western blot analysis confirmed the role of survivin in overcoming resistance. In vivo pharmacokinetic studies of EVLF in rats demonstrated a 199% relative bioavailability compared to ERL suspension. Thus, EVLF could be a promising alternative to current ERL formulations in the treatment of NSCLC.

Soft spot analysis helps evaluate the site of the metabolic lability that impacts the bio-availability of the drug. However, given its laborious and time consuming experimentation, we propose a reliable and cheap in silico strategy. In this context, we hypothesized a mechanistic rationale for metabolism of erlotinib by the CYP3A4 enzyme. The comparison of the 3D conformations of the target CYP class of enzymes using MD simulations with GROMACS helped evaluate its impact on the metabolism. The molecular docking studies using Autodock-Vina ascertained the explicit role of the Fe ion present in the Heme moiety in this process. This mechanism was confirmed with respect to 13 other popular approved FDA kinase inhibitors using ab initio DFT calculations using Gaussian 09 (G09), molecular docking studies with Autodock-Vina, and MD simulations with GROMACS. We then developed a quantitative (Q-Met) metabolic profile of these soft spots in the molecules and demonstrated the lack of a linear relationship between the extent of metabolism and drug efficacy. We thus propose an economic in silico strategy for the early prediction of the lability in kinase inhibitors to help model their bio-availability and activity simultaneously, prior to clinical testing.

Overcoming the efflux mediated by ATP-binding cassette (ABC) transporters at the blood-brain barrier (BBB) remains a challenge for the delivery of small molecule tyrosine kinase inhibitors (TKIs) such as erlotinib to the brain. Inhibition of ABCB1 and ABCG2 at the mouse BBB improved the BBB permeation of erlotinib but could not be achieved in humans. BBB disruption induced by focused ultrasound (FUS) was investigated as a strategy to overcome the efflux transport of erlotinib in vivo. In rats, FUS combined with microbubbles allowed for a large and spatially controlled disruption of the BBB in the left hemisphere. ABCB1/ABCG2 inhibition was performed using elacridar (10 mg/kg i.v). The brain kinetics of erlotinib was studied using 11 C-erlotinib Positron Emission Tomography (PET) imaging in 5 groups (n = 4-5 rats per group) including a baseline group, immediately after sonication (FUS), 48 h after FUS (FUS + 48 h), elacridar (ELA) and their combination (FUS + ELA). BBB integrity was assessed using the Evan's Blue (EB) extravasation test. Brain exposure to 11 C-erlotinib was measured as the area under the curve (AUC) of the brain kinetics (% injected dose (%ID) versus time (min)) in volumes corresponding to the disrupted (left) and the intact (right) hemispheres, respectively. EB extravasation highlighted BBB disruption in the left hemisphere of animals of the FUS and FUS + ELA groups but not in the control and ELA groups. EB extravasation was not observed 48 h after FUS suggesting recovery of BBB integrity. Compared with the control group (AUC Baseline  = 1.4 ± 0.5%ID.min), physical BBB disruption did not impact the brain kinetics of 11 C-erlotinib in the left hemisphere (p > .05) either immediately (AUC FUS  = 1.2 ± 0.1%ID.min) or 48 h after FUS (AUC FUS+48h  = 1.1 ± 0.3%ID.min). Elacridar similarly increased 11 C-erlotinib brain exposure to the left hemisphere in the absence (AUC ELA  = 2.2 ± 0.5%ID.min, p < .001) and in the presence of BBB disruption (AUC FUS+ELA  = 2.1 ± 0.5%ID.min, p < .001). AUC left was never significantly different from AUC right (p > .05), in any of the tested conditions. BBB integrity is not the rate limiting step for erlotinib delivery to the brain which is mainly governed by ABC-mediated efflux. Efflux transport of erlotinib persisted despite BBB disruption., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The aim of this study to develop galactosylated erlotinib liposomes for treatment of lung cancer. The liposomes were prepared by using solvent evaporation method. Various parameters such as particle size, zeta potential, entrapment efficiency, stability and in vitro drug release were determined. The size of liposomes (both conventional and modified) was 103.5 and 121.4 nm. The zeta potential and EE of both liposomes were -7.1 ± 1.3 mV, -1.2 ± 0.5 mV and (82.3 ± 1.9)%, (83.4 ± 1.5)%, respectively. It was found that modified liposomes increase the size of particles. The in vitro release results indicated that the release of erlotinib from galactosylated liposomes was similar to that of conventional liposome, demonstrating that the modification did not affect erlotinib release. From the result of in vivo, it proved that erlotinib liposomes can significantly improve the drug targeting, rapidly distribute the drug in the body, prolong the drug circulation time and significantly increase the relative bioavailability of the drug. Biodistribution studies showed that erlotinib from galactosylated liposomes had higher AUC inside liver than the injection group and no histological change occurred to the rat liver after the administration of erlotinib conventional and galactosylated liposomes.

Background: Erlotinib is used for treating non-small cell lung cancer (NSCLC). Intestinal absorption of erlotinib is impaired under gastric pH elevation; therefore, coadministration of gastric acid suppressants may provide lower blood concentration of erlotinib. We investigated the effects of erlotinib coadministration with proton pump inhibitors (PPIs) and histamine H2 receptor blockers (H2RBs) on the plasma concentration of erlotinib and erlotinib-induced adverse reaction in patients with NSCLC., Methods: Forty-two patients receiving erlotinib therapy for NSCLC were recruited for this study. Association of adverse reactions (rash and diarrhea) with plasma concentration of erlotinib was examined. Plasma concentration-to-dose (C/D) ratios and oral clearance (CL/F), which was estimated by population pharmacokinetic analysis of plasma concentrations of erlotinib, were compared among 3 patient groups: without coadministration of gastric acid suppressants (control group), with coadministration of PPI (PPI group), and coadministration of H2RB (H2RB group)., Results: Patients with grade ≥2 rash had higher plasma concentrations of erlotinib compared with those with grade ≤1 [1.02 (0.43-2.60) versus 0.67 (0.10-1.85) mcg/mL, P < 0.01]. The C/D ratios of erlotinib in the PPI and H2RB groups were lower than that in the control group [0.39 (0.08-0.76) and 0.48 (0.33-0.81) versus 0.51 (0.28-1.28) mcg·mL·mg·kg], where statistical significance was observed between PPI and control groups (P < 0.05). The population pharmacokinetic estimated oral CL/F in the PPI and H2RB groups were higher than that in the control group [5.55 (3.36-14.52) and 4.82 (2.08-6.32) versus 3.95 (2.01-10.44) L/h], where statistical significance was observed between PPI and control groups (P < 0.05)., Conclusions: Plasma concentrations of erlotinib in patients under coadministration of gastric acid suppressants were lower than those without gastric acid suppressants through drug interaction, suppressing the intestinal absorption of erlotinib. The magnitude of this drug interaction was more pronounced in the coadministration of PPI compared with H2RB.

Therapeutic options for the treatment of glioblastoma remain inadequate despite concerted research efforts in drug development. Therapeutic failure can result from poor permeability of the blood-brain barrier, heterogeneous drug distribution, and development of resistance. Elucidation of relationships among such parameters could enable the development of predictive models of drug response in patients and inform drug development. Complementary analyses were applied to a glioblastoma patient-derived xenograft model in order to quantitatively map distribution and resulting cellular response to the EGFR inhibitor erlotinib. Mass spectrometry images of erlotinib were registered to histology and magnetic resonance images in order to correlate drug distribution with tumor characteristics. Phosphoproteomics and immunohistochemistry were used to assess protein signaling in response to drug, and integrated with transcriptional response using mRNA sequencing. This comprehensive dataset provides simultaneous insight into pharmacokinetics and pharmacodynamics and indicates that erlotinib delivery to intracranial tumors is insufficient to inhibit EGFR tyrosine kinase signaling.

There is significant current interest in identifying new combination therapies that synergize to treat disease, and it is becoming increasingly clear that the temporal resolution of their administration greatly impacts efficacy. To facilitate effective delivery, a multicompartment hydrogel material was developed that is composed of spherical vesicles interlaced within a self-assembled peptide-based network of physically crosslinked fibrils that allows time-resolved independent co-delivery of small molecules. This material architecture effectively delivers the EGFR kinase inhibitor Erlotinib (ERL) and Doxorubicin (DOX, DNA intercalator) in an ERL→DOX sequential manner to synergistically kill glioblastoma, the most aggressive form of brain cancer., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Purpose: Posterior capsule opacification (PCO) occurs as a common complication after cataract surgery. Erlotinib is an inhibitor of the epidermal growth factor-Receptor and reduces critical cellular events leading to PCO. In this in vitro study, Erlotinib-modified intraocular lenses (IOLs) employed as a drug delivery device have been evaluated for PCO prevention., Methods: The IC 50 concentration of Erlotinib was determined by using FHL-124 cells. For the human capsular bag model, 40 cadaver eyes underwent sham cataract surgery. Sixteen capsular bags were exposed to the IC 50 of Erlotinib. Intraocular lens (IOL) of three different materials was pharmacologically modified and tested in the anterior segment model and implanted into 24 capsular bags. To test for corneal toxicity, pairs of human cornea were exposed to high concentrations of Erlotinib and corneal endothelial cells (CEC) were exposed to the modified IOL. Release kinetics of Erlotinib from the IOL was measured., Results: IC 50 of Erlotinib was determined to be 10 μm. Erlotinib alone (p = 0.002) and when soaked into IOLs (p < 0.001) significantly increased the number of days needed until total cell coverage of the capsular bags in comparison with the control. Modified IOLs mitigated cell growth in the anterior segment model (p < 0.001). No short-term corneal toxicity was observed up to a concentration of 100 μm, and IOLs did not show toxicity on CEC. Erlotinib was released constantly from IOL., Conclusion: Erlotinib might be of clinical relevance in PCO prophylaxis, as its short-term application induces a long-term deceleration of cellular growth. Erlotinib can be introduced into the eye via soaked IOLs., (© 2018 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

1. Although drug interactions between epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) and gastric acid-suppressing medications (AS) are considered clinically significant, there is limited data regarding the influence of various gastric pH conditions on the pharmacokinetics of EGFR-TKIs. We aimed to clarify the changes in the pharmacokinetics of the EGFR-TKIs, gefitinib, erlotinib and osimertinib, due to the changes in gastric pH after administration of omeprazole or vonoprazan. 2. Omeprazole (10-100 mg/kg, p.o.) and vonoprazan (1-5 mg/kg, p.o.) led to a significant and dose-dependent increase in gastric pH. 3. AUC 0-3 of gefitinib and erlotinib (5 mg/kg, p.o.) started to decrease at gastric pH 3.3 and 5.6, respectively, reached a plateau at pH > 6, and then significantly decreased up to 47 and 59% of control levels, respectively. AUC 0-3 of osimertinib (5 mg/kg, p.o.) was not significantly changed by omeprazole and vonoprazan. 4. Although there are some issues regarding the extrapolation of the results of our rat study to humans, careful monitoring of patients treated with gefitinib and erlotinib is needed in cases in which the gastric pH increases from 3 to 5 and especially when the gastric pH is >5 in patients who are co-administered both the EGFR-TKIs and AS.

Organic anion-transporting polypeptides (OATPs) mediate the uptake of various drugs from blood into the liver in the basolateral membrane of hepatocytes. Positron emission tomography (PET) is a potentially powerful tool to assess the activity of hepatic OATPs in vivo, but its utility critically depends on the availability of transporter-selective probe substrates. We have shown before that among the three OATPs expressed in hepatocytes (OATP1B1, OATP1B3, and OATP2B1), [ 11 C]erlotinib is selectively transported by OATP2B1. In contrast to OATP1B1 and OATP1B3, OATP2B1 has not been thoroughly explored yet, and no specific probe substrates are currently available. To assess if the prototypical OATP inhibitor rifampicin can inhibit liver uptake of [ 11 C]erlotinib in vivo, we performed [ 11 C]erlotinib PET scans in six healthy volunteers without and with intravenous pretreatment with rifampicin (600 mg). In addition, FVB mice underwent [ 11 C]erlotinib PET scans without and with concurrent intravenous infusion of high-dose rifampicin (100 mg/kg). Rifampicin caused a moderate reduction in the liver distribution of [ 11 C]erlotinib in humans, while a more pronounced effect of rifampicin was observed in mice, in which rifampicin plasma concentrations were higher than in humans. In vitro uptake experiments in an OATP2B1-overexpressing cell line indicated that rifampicin inhibited OATP2B1 transport of [ 11 C]erlotinib in a concentration-dependent manner with a half-maximum inhibitory concentration of 72.0 ± 1.4 μM. Our results suggest that rifampicin-inhibitable uptake transporter(s) contributed to the liver distribution of [ 11 C]erlotinib in humans and mice and that [ 11 C]erlotinib PET in combination with rifampicin may be used to measure the activity of this/these uptake transporter(s) in vivo. Furthermore, our data suggest that a standard clinical dose of rifampicin may exert in vivo a moderate inhibitory effect on hepatic OATP2B1.

Although novel molecular targeted drugs have been recognized as an effective therapy for non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) activating mutations, their efficacy fails to meet the expectation due to the acquired resistance in tumors. Up-regulation of the anti-apoptotic protein Survivin was shown to contribute to the resistance to EGFR tyrosine kinase inhibitors (TKI) in EGFR mutation-positive NSCLC. However, the unorganized tumor blood vessels impeded drug penetration into tumor tissue. The resulting insufficient intracellular drug/gene delivery in drug-resistant cancer cells remarkably weakened the drug efficacy in NSCLC. In this work, a multi-functional drug delivery system AP/ES was developed by using anti-EGFR aptamer (Apt)-modified polyamidoamine to co-deliver erlotinib and Survivin-shRNA. Chloroquine (CQ) was used in combination with AP/ES to normalize tumor vessels for sufficient drug/gene delivery to overcome drug resistance in NSCLC cells. The obtained AP/ES possessed desired physicochemical properties, good biostability, controlled drug release profiles, and strong selectivity to EGFR-mutated NSCLC mediated by Apt. CQ not only enhanced endosomal escape ability of AP/ES for efficient gene transfection to inhibit Survivin, but also showed strong vessel-normalization ability to improve tumor microcirculation, which further promoted drug delivery and enhanced drug efficacy in erlotinib-resistant NSCLC cells. Our innovative gene/drug co-delivery system in combination with CQ showed a promising outcome in fighting against erlotinib resistance both in vitro and in vivo. This work indicates that normalization of tumor vessels could help intracellular erlotinib/Survivin-shRNA delivery and the down-regulation of Survivin could act synergistically with erlotinib for reversal of erlotinib resistance in EGFR mutation-positive NSCLC., Statement of Significance: NSCLC patients who benefited from EGFR-TKIs inevitably developed acquired resistance. Previous research focused on synthesis of new generation of molecular targeted drugs that could irreversibly inhibit EGFR with a particular gene mutation to overcome drug resistance. However, they failed to inhibit EGFR with other gene mutations. Activation of bypass signaling pathway and the changes of tumor microenvironment are identified as two of the mechanisms of acquired resistance to EGFR-TKIs. We therefore constructed multifunctional gene/drug co-delivery nanocomplexes AP/ES co-formulated with chloroquine that could target the both two mechanisms. We found that chloroquine not only enhanced endosomal escape ability of AP/ES for efficient gene transfection to inhibit Survivin, but also showed strong vessel-normalization ability to improve tumor microcirculation, which further promoted drug delivery into tumor tissue and enhanced drug efficacy in erlotinib-resistant NSCLC., (Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Systemic and uncontrolled administration of erlotinib hydrochloride (ETB) is associated with severe toxicity. A novel targeted and extended release nanosponge (NS) was synthesized from glutathione (GHS) by a one-step reaction between β-cyclodextrin and pyromellitic dianhydride at room temperature for delivery of ETB in lung cancer. Characterization studies were performed using sophisticated instruments. In-vitro release study was performed in the presence of incremental concentrations of GHS which was analyzed using HPLC. Cell cytotoxicity study was evaluated on human lung cancer (A549) cell lines. In-vivo tumour inhibition and biodistribution of ETB-loaded GHS-NS (ETB-NS) were performed on BALB/c mice. NS obtained was spherical, size 212 ± 2.45 nm and high drug entrapment (92.34 ± 5.31%) (p < .001). In-vitro extended drug release (76.89 ± 0.1% release at 168 h), which was directly proportional to the concentration of GHS, demonstrated tumour targeting. There was enhanced in-vitro cytotoxicity and 97.5% inhibition in tumour growth on administering NS when compared to plain ETB (48% inhibition) indicating targeting of NS to the tumour site. Biodistribution study and in-vivo tumour growth inhibition study revealed drug release to the cancerous cell, thus preventing unnecessary drug exposure. ETB-NS exhibits extended drug release proportional to the external GSH concentration.

Background: Aim of this study was to prepare the hyaluronic acid and human serum albumin modified erlotinib nanoparticles (ERT-HSA-HA NPs) delivery system by a precipitation method., Methods: ERT-HSA-HA NPs were characterized for physical properties, such as morphology and particle size, and in vitro drug release. Moreover, the cytotoxicity, cellular uptake, in vivo studies of ERT-HSA-HA nanoparticle were investigated and compared in A549 cells., Results: The ERT-HSA-HA NPs showed spherical morphology, and their hydrodynamic diameter was 112.5±2.8 nm. The drug loading amount and encapsulation efficiency were 5.6% and 81.2%, respectively. After 3 months of storage, no dramatic change, such as visible aggregation, drug content changes, and precipitation, in the appearance of ERT-HSA-HA NPs occurred. In vitro release showed that the release of ERT from HSA-HA NPs was slow, without obvious burst effects at an early stage. In in vivo studies, ERT-HSA-HA NPs showed a superior antiproliferative effect on A549 cells, and the HA modification strategy can also facilitate the high-efficiency uptake of ERT-HSA NPs by A549 cells. Pharmacokinetic studies showed that the form of NPs could significantly extend the role of ERT in vivo (provided higher bioavailability). However, there was no significant difference in the pharmacokinetic parameters between ERT-HSA NPs and ERT-HSA-HA NPs after intravenous administration. In terms of in vivo antitumor activity, ERT-HSA-HA NP-treated mice showed a significantly suppressed tumor growth and no relapse after 30 d of treatment., Conclusion: HA/HSA co-modified erlotinib albumin nanoparticles was expected to be a new strategy in the treatment of lung cancer., Competing Interests: Disclosure The authors report no conflicts of interest in this work.

To assess the hepatic disposition of erlotinib, we performed positron emission tomography (PET) scans with [ 11 C]erlotinib in healthy volunteers without and with oral pretreatment with a therapeutic erlotinib dose (300 mg). Erlotinib pretreatment significantly decreased the liver exposure to [ 11 C]erlotinib with a concomitant increase in blood exposure, pointing to the involvement of a carrier-mediated hepatic uptake mechanism. Using cell lines overexpressing human organic anion-transporting polypeptides (OATPs) 1B1, 1B3, or 2B1, we show that [ 11 C]erlotinib is selectively transported by OATP2B1. Our data suggest that at PET microdoses hepatic uptake of [ 11 C]erlotinib is mediated by OATP2B1, whereas at therapeutic doses OATP2B1 transport is saturated and hepatic uptake occurs mainly by passive diffusion. We propose that [ 11 C]erlotinib may be used as a hepatic OATP2B1 probe substrate and erlotinib as an OATP2B1 inhibitor in clinical drug-drug interaction studies, allowing the contribution of OATP2B1 to the hepatic uptake of drugs to be revealed., (© 2017 The Authors Clinical Pharmacology & Therapeutics published by Wiley Periodicals, Inc. on behalf of American Society for Clinical Pharmacology and Therapeutics.)

Purpose: Lung cancer is the leading cause of cancer-related deaths. The aim of this study was to design solid lipid core nanocapsules (SLCN) comprising a solid lipid core and a PEGylated polymeric corona for paclitaxel (PTX) and erlotinib (ERL) co-delivery to non-small cell lung cancer (NSCLC), and evaluate their physicochemical characteristics and in vitro activity in NCI-H23 cells., Methods: PTX/ERL-SLCN were prepared by nanoprecipitation and sonication and physicochemically characterized by dynamic light scattering, transmission electron microscopy, differential scanning calorimetry, X-ray diffraction, and Fourier-transform infrared spectroscopy. In vitro release profiles at pH 7.4 and pH 5.0 were studied and analyzed. In vitro cytotoxicity and cellular uptake and apoptosis assays were performed in NCI-H23 cells., Results: PTX/ERL-SLCN exhibited appropriately-sized spherical particles with a high payload. Both PTX and ERL showed pH-dependent and sustained release in vitro profiles. PTX/ERL-SLCN demonstrated concentration- and time-dependent uptake by NCI-H23 cells and caused dose-dependent cytotoxicity in the cells, which was remarkably greater than that of not only the free individual drugs but also the free drug cocktail. Moreover, well-defined early and late apoptosis were observed with clearly visible signs of apoptotic nuclei., Conclusion: PTX/ERL-SLCN could be employed as an optimal approach for combination chemotherapy of NSCLC.

Determinants of interindividual variability in erlotinib pharmacokinetics (PK) and adverse events remain to be elucidated. This study with 50 Japanese non-small-cell lung cancer patients treated with oral erlotinib at a standard dose of 150 mg aimed to investigate whether genetic polymorphisms affect erlotinib PK and adverse events. Single nucleotide polymorphisms (SNPs) in genes encoding metabolizing enzymes (CYP1A1, CYP1A2, CYP2D6, CYP3A4, CYP3A5, UGT1A1, UGT2B7, GSTM1, and GSTT1) or efflux transporters (ABCB1, and ABCG2) were analyzed as covariates in a population PK model. The ABCB1 1236C>T (rs1128503) polymorphism, not ABCB1*2 haplotype (1236TT-2677TT-3455TT, rs1128503 TT-rs2032582 TT-rs1045642 TT), was a significant covariate for the apparent clearance (CL/F), with the TT genotype showing a 29.4% decrease in CL/F as compared with the CC and the CT genotypes. A marginally higher incidence of adverse events (mainly skin rash) was observed in the TT genotype group; however, patients with high plasma erlotinib exposure did not always experience skin rash. None of the other SNPs affected PK or adverse events. The ABCB1 genotype is a potential predictor for erlotinib adverse events. Erlotinib might be used with careful monitoring of adverse events in patients with ABCB1 polymorphic variants.

The aim of this study was to develop PEGylation liposomes formulations of erlotinib and evaluate their characteristics, stability, and release characteristics. The average particle sizes and entrapment efficiency of PEGylation erlotinib liposomes are 102.4±3.1 nm and 85.3%±1.8%, respectively. Transmission electron microscopy images showed that the liposomes dispersed well with a uniform shape and no changes during the storage. The in vitro drug-release kinetic model of erlotinib release from the PEGylation liposomes in phosphate-buffered saline fit well with the Higuchi equation. In vitro anticancer activity assay showed that the blank liposomes had lower cellular cytotoxicity and that the cellular cytotoxicity of erlotinib liposomes increased significantly under the same incubation condition, which should contribute to the increase in intracellular drug concentration by the transportation of liposomes. The two liposomes of erlotinib (with and without PEGylation) exhibited similar cellular cytotoxicity with no significantly different concentrations. Pharmacokinetic results indicated that erlotinib-loaded PEGylation liposomes can significantly change the pharmacokinetic behavior of drugs and improve the drug bioavailability by nearly 2 times compared to ordinary liposomes. No sign of damages such as the appearance of epithelial necrosis or sloughing of epithelial cells was detected in histological studies., Competing Interests: Disclosure The authors report no conflicts of interest in this work.

Combination therapy of erlotinib plus bevacizumab improves progression-free survival of patients with epidermal growth factor receptor-mutated (EGFR-mutated) advanced non-small-cell lung cancer (NSCLC) compared with erlotinib alone. Although improved delivery and distribution of erlotinib to tumours as a result of the normalization of microvessels by bevacizumab is thought to be one of the underlying mechanisms, there is insufficient supporting evidence. B901L cells derived from EGFR-mutated NSCLC were subcutaneously implanted into mice, and mice were treated with bevacizumab or human IgG followed by treatment with erlotinib. The distribution of erlotinib in their tumours at different times after erlotinib administration was analysed by matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI). We also analysed the distribution of erlotinib metabolites and the distribution of erlotinib in tumours refractory to erlotinib, which were established by long-term treatment with erlotinib. We found that erlotinib was broadly diffused in the tumours from B901L-implanted xenograft mice, independently of bevacizumab treatment. We also found that erlotinib metabolites were co-localized with erlotinib and that erlotinib in erlotinib-refractory tumours was broadly distributed throughout the tumour tissue. Multivariate imaging approaches using MALDI MSI as applied in this study are of great value for pharmacokinetic studies in drug development.

Background: Epidermal growth factor receptor (EGFR) and phosphatidylinositol 3-kinase (PI3K) are involved in the proliferation and survival of many cancer types. Enhanced antitumor activity may be achieved through combined inhibition of these pathways. We report results for pictilisib (GDC-0941, a class I pan-PI3K inhibitor) plus erlotinib (an EGFR tyrosine kinase inhibitor) in patients with advanced solid tumors., Materials and Methods: A 3 + 3 dose-escalation study was carried out at a starting daily dose of 60 mg pictilisib on days 1-21 of a 28-day cycle and 150 mg erlotinib from day 2 of cycle 1. The primary objectives of the study were to assess safety and tolerability, identify dose-limiting toxicities (DLTs), estimate the maximum tolerated dose, and identify the recommended phase II dose (RP2D). Evaluation of a dose-expansion cohort at the RP2D was performed., Results: Fifty-seven patients were treated in the study. All patients experienced at least one adverse event (AE). Grade ≥3 AEs, serious AEs, and deaths were reported in 38 (66.7%), 19 (33.3%), and 4 (7.0%) patients, respectively. DLTs occurred in nine patients across eight cohorts and the RP2D was determined to be 340 mg pictilisib on a "5 days on, 2 days off" schedule plus 100 mg erlotinib. Two patients (3.5%) experienced partial response and 19 (33.3%) had stable disease., Conclusion: Combining pictilisib with erlotinib in patients with advanced solid tumors is feasible; however, antitumor activity is limited. Additional studies may identify patients likely to benefit from combined inhibition of EGFR and PI3K pathways., Implications for Practice: Combining drugs targeting different signaling pathways in cancer growth and survival could overcome drug resistance and improve antitumor activity. In this first-in-human study for the combination, addition of the PI3K inhibitor pictilisib to the EGFR tyrosine kinase inhibitor erlotinib resulted in toxicity that led to dose and schedule modifications to identify a tolerable recommended phase II dose of 340 mg pictilisib on a "5 days on, 2 days off" schedule plus 100 mg erlotinib daily. The limited antitumor activity observed, however, suggests that additional studies are needed to identify patients most likely to benefit from combined EGFR and PI3K inhibition., Competing Interests: Disclosures of potential conflicts of interest may be found at the end of this article., (© AlphaMed Press 2017.)

Erlotinib as a first-line drug is used in non-small cell lung cancer (NSCLC) patients with sensitive EGFR mutations, while resistance to this drug will occur after several years of treatment. Therefore, the microtubule disturber docetaxel is introduced as combined regimen in clinical trials. This report investigated the potentials and mechanisms of drug-drug interaction (DDI) between erlotinib and docetaxel using wild type (WT) and Cyp3a1/2 knockout (KO) rats. The erlotinib O-demethylation and docetaxel hydroxylation reactions in the absence or the presence of another drug were analyzed in vitro via the assay of rat liver microsomes. In whole animal studies, erlotinib and docetaxel were given to WT and KO rats individually or jointly, and the pharmacokinetic profiles of these two drugs were analyzed and compared among different groups. The results showed that docetaxel not only inhibited the CYP3A-mediated biotransformation of erlotinib in vitro, but also significantly increased the maximum concentration and systemic exposure of erlotinib in vivo in WT rats. In contrast, the DDI was significantly attenuated in KO rats. On the other hand, erlotinib did not influence docetaxel either in vitro biotransformation or in vivo pharmacokinetic behaviors. These results exhibited the potentials of erlotinib-docetaxel interaction and indicated that the CYP3A played the perpetrating role of docetaxel on erlotinib in rats. A better understanding of this DDI with CYP3A may help the regulation of the use of these two drugs, avoid potential problems, and adjust dose carefully and early in clinic., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Molecular imaging using radiolabeled Tyrosine Kinase Inhibitors (TKI) is a promising strategy for detection and staging of EGFR-positive cancers. A novel analogue of one such TKI, Erlotinib has been developed for PET imaging by derivatizing the parent Erlotinib molecule for conjugation with the bifunctional chelator p-SCN-Bn-NOTA towards radiolabeling with 68 Ga. NOTA-Erlotinib conjugate was synthesized and characterized by NMR and ESI-MS techniques. The conjugate was radiolabeled with 68 Ga in 95±2% yield, as evidenced by HPLC characterization. The logP value of 68 Ga-NOTA-Erlotinib was - (0.6±0.1). The 68 Ga-NOTA-Erlotinib conjugate was characterized using its nat Ga-NOTA-Erlotinib surrogate. Cell viability studies showed that the NOTA-Erlotinib conjugate retained the biological efficacy of the parent Erlotinib molecule. Further, 68 Ga-NOTA-Erlotinib exhibited an uptake of 9.8±0.4% in A431 cells which was inhibited by 55.1±0.2% on addition of cold Erlotinib (10µg) confirming the specificity of the radioconjugate for EGFR expressing cells. In the biodistribution studies carried out in tumor bearing SCID mice, 68 Ga-NOTA-Erlotinib conjugate showed moderate tumor accumulation (1.5±0.1% ID/g at 30minp.i.; 0.7±0.2% ID/g at 1hp.i.). Hepatobiliary clearance of the radioconjugate was observed. The 68 Ga-NOTA-Erlotinib conjugate was found to have high in vivo stability as determined by the metabolite analysis study using urine sample of the Swiss mice injected with the preparation. The overall properties of 68 Ga-NOTA-Erlotinib are promising and merit further exploration. To the best of our knowledge, this is the first report on the design of a 68 Ga labeled Erlotinib for PET imaging of EGFR and opens avenues for the successful development of 68 Ga labeled TKI for imaging of EGFR over-expressing tumors., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Erlotinib is metabolized by cytochrome p450 (CYP) 3A and CYP1A. This study assessed CYP3A4 (midazolam) and CYP1A2 (caffeine) phenotyping in plasma and dried blood spots (DBS) for predicting the pharmacokinetics and toxicity of erlotinib in 36 patients with advanced NSCLC. On day 1, erlotinib 150 mg OD was initiated, and the two oral probe drugs midazolam (2 mg) and caffeine (100 mg) were added on day 1. Plasma and DBS were collected for erlotinib, OSI-420 and probe drugs for up to 6 hr on day 1 and 2-weekly up to week 10. Probe drugs, erlotinib and OSI-420 were analysed using LC-MS-MS, and PK data were processed using population modelling. A high correlation was found between plasma and DBS concentrations for erlotinib (R 2  = 0.960, p < 0.0001), OSI-420 (R 2  = 0.971, p < 0.0001), midazolam (R 2  = 0.995, p < 0.0001) and caffeine (R 2  = 0.968, p < 0.0001). Apparent oral caffeine clearance was significantly correlated with erlotinib clearance (R 2  = 0.33, p = 0.048), while midazolam clearance was not (R 2  = -0.09, p = 0.596). Erlotinib clearance was lower in patients experiencing grade 2 or 3 rash as compared to patients experiencing grade 0 or 1 rash (3.15 versus 3.93 L/hr, p = 0.086 for Student's t-test). The results suggest that probe drug phenotyping is unlikely to substitute therapeutic drug monitoring of erlotinib in patients with advanced NSCLC, but erlotinib PK sampling from DBS may replace more invasive venous sampling and facilitate TDM in patients with cancer., (© 2017 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).)

Gemcitabine and erlotinib are the chemotherapeutic agents used in the treatment of various cancers and their combination is being accepted as a first-line treatment of advanced pancreatic cancer. Hyangsayukgunja-tang (HYT) is a traditional oriental medicine used in various digestive disorders and potentially helpful to treat gastrointestinal adverse effects related to chemotherapy. The present study was aimed to evaluate the effect of HYT on the pharmacokinetics of gemcitabine and erlotinib given simultaneously in rats. Rats were pretreated with HYT at an oral dose of 1200 mg/kg/day once daily for a single day or 14 consecutive days. Immediately after pretreatment with HYT, gemcitabine and erlotinib were administered by intravenous injection (10 mg/kg) and oral administration (20 mg/kg), respectively. The effects of HYT on pharmacokinetics of the two drugs were estimated by non-compartmental analysis and pharmacokinetic modeling. The pharmacokinetics of gemcitabine and erlotinib were not altered by single dose HYT pretreatment. However, the plasma levels of OSI-420 and OSI-413, active metabolites of erlotinib, were significantly decreased in the multiple dose HYT pretreatment group. The pharmacokinetic model estimated increased systemic clearances of OSI-420 and OSI-413 by multiple doses of HYT. These data suggest that HYT may affect the elimination of OSI-420 and OSI-413., Competing Interests: The authors declare no conflict of interest.

Objectives: Nanoparticulation using fat and supercritical fluid (NUFS TM ) is a drug delivery platform technology enabling efficient and effective formulation of poorly soluble drugs. We performed experiments to examine whether NUFS™ could improve poor bioavailability and reduce fed-fasted bioavailability variances of erlotinib (Ert)., Methods: NUFS-Ert was prepared using NUFS™ technology; its physical properties were characterized, and drug release was measured. Furthermore, in vitro and in vivo efficacy tests and pharmacokinetic analysis were performed., Results: NUFS-Ert nanoparticles had an average size of 250 nm and were stable for 2 months at 40 °C, 4 °C, and room temperature. The dissolution rate of NUFS-Ert increased in bio-relevant dissolution media. NUFS-Ert was more potent in inhibiting EGF signaling and in suppressing the proliferation of A549, a human non-small cell lung cancer cell line. Furthermore, A549 xenografts in BALB/c nude mice treated with NUFS-Ert regressed more efficiently than those in the mice treated with vehicle or Tarceva ® . In addition, experimental lung metastasis was more efficiently inhibited by NUFS-Ert than by Tarceva ® . The relative bioavailability of NUFS-Ert compared with that of Tarceva ® was 550% and the ratio of the area under the concentration-time curve (AUC) of fed state to the AUC of fasted state was 1.8 for NUFS-Ert and 5.8 for Tarceva ® ., Conclusions: NUFS-Ert could improve poor bioavailability and reduce fed-fasted bioavailability variances of Ert. NUFS-Ert was more efficacious than Tarceva ® .

The main objective of this study was to develop a pharmacokinetic model in order to describe the intestinal absorption of erlotinib in rat and to quantify the interaction of levofloxacin on this process in well- and under-nourished rats. Absorption studies were performed in male Wistar rats. Concentration-time profiles in proximal and distal intestine were analysed through non-linear mixed effect modelling using the NONMEM software version 7.3. Simulations were performed in order to explore the influence of covariates on the apparent absorption rate constant. A passive absorption and an active secretion process best-described erlotinib absorption from lumen to enterocyte. The developed model indicates that levofloxacin exerts an inhibition on erlotinib efflux transporters of the gut epithelium. Undernourishment proved to significantly decrease the maximum capacity of the secretion process. Simulations evidenced that erlotinib absorption only takes place at high enough drug concentrations to overcome the effect of efflux transporters. On the other hand, when levofloxacin is present in the intestinal lumen of undernourished rats, erlotinib drug absorption takes place even at low erlotinib concentrations. In the clinical setting, this interaction may result in increased exposure to erlotinib, especially in undernourished cancer patients. Copyright © 2017 John Wiley & Sons, Ltd., (Copyright © 2017 John Wiley & Sons, Ltd.)