Determination of intracellular anlotinib, osimertinib, afatinib and gefitinib accumulations in human brain microvascular endothelial cells by liquid chromatography/tandem mass spectrometry.

RATIONALE: Brain metastases are a common complication in patients with non-small-cell lung cancer (NSCLC). Anlotinib hydrochloride is a novel multi-target tyrosine kinase inhibitor (TKI) exhibiting a superior overall response rate for brain metastases from NSCLC. The penetrability of anlotinib and three generations of epidermal growth factor receptor (EGFR) TKIs (osimertinib, afatinib and gefitinib) into brain microvascular endothelial cells (HBMECs) was compared. METHODS: A sensitive quantification method for the four TKIs was developed using liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS). Anlotinib and the three EGFR TKIs were separated on an ACQUITY BEH C18 column after a direct protein precipitation, and then analyzed using electrospray ionization in positive ion mode. The linearity, accuracy, precision, limit of quantification, specificity and stability were assessed. RESULTS: The four analytes could be efficiently quantified in a single run of 3.8 min. The validation parameters of all analytes satisfy the acceptance criteria of bioanalytical method guidelines. The calibration range was 0.2-200 ng mL-1 for anlotinib and gefitinib, 1-500 ng mL-1 for osimertinib and 1-200 ng mL-1 for afatinib. The penetration of anlotinib across HBMECs was comparable with that of afatinib and gefitinib but less than that of osimertinib. CONCLUSIONS: A sensitive LC/MS/MS method to simultaneously measure anlotinib, osimertinib, afatinib and gefitinib in cell extracts was successfully validated and applied to determine their uptake inside HBMECs, which could pave the way for future research on the role of anlotinib in NSCLC brain metastases.

Effects of the ABCB1 and ABCG2 polymorphisms on the pharmacokinetics of afatinib in healthy Chinese volunteers.

1. Afatinib is an oral, selective tyrosine kinase inhibitor (TKI) primarily transported by P-glycoprotein (MDR1, gene code ABCB1) and breast cancer resistance protein (BCRP, gene code ABCG2). In the present study, the effects of ABCB1 and ABCG2 genetic polymorphisms on the pharmacokinetics of afatinib in healthy Chinese were investigated.2. Blood samples from 24 healthy participants who received afatinib were used for genotyping ABCB1 (1236C>T, 2677G > T/A, 3435C>T) and ABCG2 (34G>A, 421C>A) polymorphisms. Subsequently, the association between afatinib plasma concentrations and target single-nucleotide polymorphisms (SNPs) was analyzed.3. Among the five polymorphisms, plasma concentrations of afatinib in healthy subjects with ABCB1 1236CC-3435CC were remarkably higher than in other genotype subjects. No significant differences of afatinib exposure were found between the ABCG2 wild-type and heterozygous groups.4. The ABCB1 genetic polymorphism influenced the plasma exposure of afatinib, and gene testing before drug administration may be useful for clinically individualized use of afatinib. Our data suggest the usefulness of afatinib pharmacogenetics in treatment optimization.

Phase I dose-escalation trial of afatinib, an irreversible ErbB family blocker, in combination with gemcitabine or docetaxel in patients with relapsed or refractory solid tumors.

Background Afatinib, an irreversible ErbB family blocker, has shown synergistic antitumor activity and manageable tolerability in combination with chemotherapy. This phase I study assessed oral afatinib plus intravenous gemcitabine or docetaxel in patients with relapsed/refractory solid tumors. Methods Patients received afatinib (30, 40, or 50 mg) plus gemcitabine (1000 or 1250 mg/m2) or docetaxel (60 or 75 mg/m2). Dose escalation proceeded via a 3 + 3 design until the maximum tolerated dose (MTD) was reached. Adverse events (AEs), pharmacokinetics and antitumor activity were also assessed. Results Dose-limiting toxicities during Cycle 1 were reported in 6/39 patients receiving afatinib/gemcitabine (most commonly diarrhea, thrombocytopenia and vomiting) and 16/54 patients receiving afatinib/docetaxel (most commonly febrile neutropenia and stomatitis). The MTDs were established as afatinib 40 mg/gemcitabine 1000 mg/m2 and afatinib 30 mg/docetaxel 60 mg/m2. The most common drug-related AEs were diarrhea, asthenia and rash with afatinib/gemcitabine, and diarrhea, asthenia and stomatitis with afatinib/docetaxel. No relevant pharmacokinetic interactions were observed for either combination. Both combinations demonstrated clinical activity and durable disease control at the MTDs. Compared with the MTD, higher response rates were achieved with afatinib 30 mg/docetaxel 75 mg/m2 (28% vs 6%); however, this regimen was associated with problematic febrile neutropenia, an expected AE with docetaxel, that is often managed with growth factor support. Conclusions Afatinib/gemcitabine and afatinib/docetaxel demonstrated manageable safety profiles, with evidence of clinical efficacy at the MTDs. For afatinib/docetaxel, a dose level of afatinib 30 mg/docetaxel 75 mg/m2 produced higher response rates. Trial registration: NCT01251653 ( ClinicalTrials.gov ).

Effects of polymorphisms in pregnane X receptor and ABC transporters on afatinib in Japanese patients with non-small cell lung cancer: pharmacogenomic-pharmacokinetic and exposure-response analysis.

PURPOSE: Because of the large interindividual variability of afatinib pharmacokinetics and adverse events, we evaluated the effects of polymorphisms in pregnane X receptor (NR1I2) and ABC transporters (ABCB1, ABCG2, and ABCC2) on the pharmacokinetics of afatinib. METHODS: The steady-state area under the concentration-time curve (AUC)0-24 of afatinib was analyzed using blood sampling just prior to and at 1, 2, 4, 6, 8, 12, and 24 h on day 15 after administration. RESULTS: The median oral clearance (CL/F) of afatinib in patients with the NR1I2 7635A allele was significantly lower than those in patients with the 7635G/G genotype (42.0 and 60.0 L/h, respectively, P = 0.025). There were no significant differences in afatinib CL/F between genotypes for NR1I2 8055C > T, -25385C > T, ABCB1, ABCG2, and ABCC2 polymorphisms. Based on the area under the receiver-operating characteristic curve, the threshold afatinib AUC0-24 value for prediction of dose reduction or withdrawal was 689 ng·h/mL at the best sensitivity (81.0%) and specificity (72.7%). In multivariate logistic regression analysis, an afatinib AUC0-24 above 689 ng·h/mL was independently associated with increased risk of dose reduction or withdrawal (OR: 11.66, P = 0.012). CONCLUSIONS: The NR1I2 7635A allele was related to a lower afatinib CL/F. Based on the AUC of 689 ng h/mL and CL/F, the optimal doses for patients with the NR1I2 7635G/G genotype and 7635A allele were recommended to be set at 40 and 30 mg/day, respectively, and subsequent adjustment of the maintenance dose based on the plasma concentrations of afatinib may be necessary to avoid afatinib-related adverse events.

Pharmacokinetic and pharmacogenomic analysis of low-dose afatinib treatment in elderly patients with EGFR mutation-positive non-small cell lung cancer.

PURPOSE: An increasing number of advanced non-small cell lung cancer (NSCLC) cases are being reported in the ageing population. However, studies on the use of afatinib in elderly patients are scarce. We conducted a prospective multicentre, single-arm, and open-label phase II trial for low-dose afatinib (30 mg/day) use in elderly patients with NSCLC with EGFR mutation to assess quality-of-life (QOL) and pharmacokinetic (PK)/pharmacogenomic (PGx) parameters. PATIENTS AND METHODS: The primary end-point was the objective response rate (ORR), and the planned number of registered cases was 35, with a threshold ORR of 50%, an expected ORR of 75%, α of 0.05, and ß of 0.1. Secondary end-points were progression-free survival (PFS), overall survival (OS), the incidence rate of adverse events (AEs), QOL survey (FACT-L), and trough plasma concentration of afatinib at steady state (Css) and at the occurrence of clinically significant AEs. RESULTS: The median age of the patients was 79 years. The ORR was 80.0% and the disease control rate was 91.4%. The median PFS and OS were 15.6 and 29.5 months, respectively. Four patients discontinued because of AEs. Treatment-related death was not observed. No significant change in QOL was observed at baseline and after 4, 8, and 12 weeks. Css was comparable with those in previous reports and was significantly higher in patients with grade 3 AEs. Direct correlations between afatinib treatment and PGx profiles were not observed. CONCLUSIONS: An afatinib starting dose of 30 mg/day could be an effective and safe treatment option for elderly patients.

Immunohistochemical localization of afatinib in male rat intestines and skin after its oral administration.

Afatinib, a second-generation tyrosine kinase inhibitor, was designed to bind covalently to and irreversibly inhibit active ErbB family receptors. The major metabolites of afatinib in human plasma are adducts of afatinib covalently bound to plasma proteins via. the Michael addition reaction. These findings suggest that afatinib may form covalent bonds with proteins in tissue and be localized in tissue. However, there is no method for the specific detection of afatinib-protein conjugates localized in tissue. In this paper, we aimed to develop an immunohistochemical protocol to detect afatinib-protein conjugates. Immunostainings were performed with male rat intestinal tract and skin at 24 h after an oral administration of afatinib. In the intestinal tract, strong staining was observed in the ileum and colon, but only slight staining was observed in the duodenum and jejunum. In the skin, strong staining was observed in the epidermis, sebaceous glands and hair follicles. Immunohistochemistry for afatinib-protein conjugates could be a useful tool to detect the localization of such conjugates. This study is the first to elucidate the localization of afatinib-protein conjugates in the rat intestinal tract and skin and is expected to be of great use in efforts to clarify the mechanism underlying afatinib-induced diarrhoea or skin toxicities.

Quantification of afatinib, alectinib, crizotinib and osimertinib in human plasma by liquid chromatography/triple-quadrupole mass spectrometry; focusing on the stability of osimertinib.

The development and full validation of a sensitive and selective ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) method are described for the simultaneous analysis of afatinib, alectinib, crizotinib and osimertinib in human lithium heparinized plasma. Afatinib-d6, crizotinib-d5 and erlotinib-d6 were used as internal standards. Given osimertinib's instability in plasma and whole blood at ambient temperature, samples should be solely processed on ice (T = 0 °C). Chromatographic separation was obtained on an Acquity UPLC ® BEH C18; 2.1 × 50 mm, 1.7 µm column, which was eluted with 0.400 mL/minute flow on a linear gradient, consisting of 10 mM ammonium formate (pH 4.5) and acetonitrile. Calibration curves for all compounds were linear for concentration ranges of 1.00 to 100 ng/mL for afatinib and 10.0 to 1000 ng/mL for alectinib, crizotinib and osimertinib, herewith validating the lower limits of quantification at 1.00 ng/mL for afatinib and 10.0 ng/mL for alectinib, crizotinib and osimertinib. Within-run and between-run precision measurements fell within 10.2%, with accuracy ranging from 89.2 to 110%.

Nilotinib Alters the Efflux Transporter-Mediated Pharmacokinetics of Afatinib in Mice.

Small-molecule tyrosine kinase inhibitors (TKIs) are novel anticancer agents with enhanced selectivity and superior safety profiles than conventional chemotherapeutics. A major shortcoming in TKI therapy is the development of acquired resistance. An important resistance mechanism is reduced intracellular drug accumulation due to an overexpression of efflux transporters such as P-glycoprotein (Pgp) and breast cancer resistance protein (BCRP) in cancer cells. TKIs have dual roles as substrates and inhibitors of Pgp and BCRP; thus, combination TKI therapy could potentially reverse efflux transporter-mediated TKI resistance. In the present study, the effect of 14 TKIs on Pgp-, Bcrp1-, and BCRP-mediated afatinib efflux was investigated in vitro. Nilotinib was a potent inhibitor of Pgp, Bcrp1, and BCRP, with EC50 values of 2.22, 2.47, and 0.692 µM, respectively. Consequently, the pharmacokinetics of afatinib with and without the coadministration of nilotinib was determined in mice plasma and various tissues. Nilotinib increased afatinib AUC by 188% in plasma, and this altered tissue AUC by -38.8% to +221%. Nilotinib also decreased the clearance of afatinib by 65.3%, from 609 to 211 mL/h. Further studies are warranted to assess nilotinib's chemosensitizing effect in tumor xenograft models.

Afatinib-loaded immunoliposomes functionalized with cetuximab: A novel strategy targeting the epidermal growth factor receptor for treatment of non-small-cell lung cancer.

Afatinib, a selective and irreversible inhibitor of tyrosine kinase, was approved for the treatment of advanced non-small-cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) overexpression in 2013. Cetuximab (CTX), an anti-EGFR monoclonal antibody, is co-administered with afatinib to improve efficacy. Unfortunately, dose-related adverse reactions caused by combination therapy have affected patient compliance, and have resulted in treatment discontinuation in severe cases. In the present study, afatinib was encapsulated in "liposomes" (LPs) to achieve longer circulation in the blood and an enhanced permeability-and-retention effect in tumors. Concomitantly, CTX was designed to bind to drug-loaded LPs to form "immuno-LPs" for tumor-cell selectivity and therapeutic activity. In vitro, the cellular internalization rate of immuno-LPs was significantly higher than that of LPs (p < 0.05). In vivo, a markedly increased area under the curve and prolonged terminal half-life were detected in rats injected with the two LP formulations, indicating that LP encapsulation protected afatinib from binding to hemoglobin to control the risk of idiosyncratic drug reactions. Compared with free afatinib and LPs, immuno-LPs exhibited strongly enhanced drug delivery and antitumor efficacy in an NSCLC xenograft model, with stronger tumor selectivity and potentially fewer side-effects. Hence, EGFR-targeting immuno-LPs appear to be promising for NSCLC treatment.

Non-small cell lung cancer-targeted, redox-sensitive lipid-polymer hybrid nanoparticles for the delivery of a second-generation irreversible epidermal growth factor inhibitor-Afatinib: In vitro and in vivo evaluation.

Afatinib (Afa), a second-generation irreversible epidermal growth factor inhibitor for the development of non-small cell lung cancer, has low bioavailability and adverse reactions. Nanoscaled drug delivery systems offer promising alternatives to address these defects and improve therapeutic outcomes. In the present study, a Tf contained, redox-sensitive ligand was synthesized and used for the preparation of afatinib loaded, Tf modified redox-sensitive lipid-polymer hybrid nanoparticles (Tf-SS-Afa-LPNs). Subsequently, studies of biological experiments in vitro and in vivo were performed to investigate the therapeutic effect of the system in lung cancer. The results showed that Tf-SS-Afa-LPNs has particle size of 103.5 ± 4.1 nm and zeta potential of -21.2 ± 2.4 mV. Significantly higher drug release was observed in the presence of glutathione (GSH). The area under the plasma concentration - time curve (AUC), peak concentration (Cmax) and terminal half life (T1/2) of Tf-SS-Afa-LPNs were 866.56 mg/L.h, 25.62 ± 3.21 L/kg/h, and 43.25 ± 2.31 h. Tf-SS-Afa-LPNs exhibited the most remarkable in vivo anti-tumor efficiency efficacy, which inhibited the tumor volume from 919 mm3 to 212 mm3. Tf-SS-Afa-LPNs is a promising platform for the lung cancer treatment.

Population pharmacokinetics of afatinib and exposure-safety relationships in Japanese patients with EGFR mutation-positive non-small cell lung cancer.

To investigate the exposure-safety relationships of afatinib in Japanese population, we performed population pharmacokinetics (PK) analysis of afatinib in Japanese advanced non-small cell lung cancer patients harboring epidermal growth factor receptor mutation. Plasma samples were collected at 0.5-1, 2-3, 8-12, and 24 h after oral afatinib (40 mg) administration on day 1 and day 8. Plasma afatinib concentrations were determined using high-performance liquid chromatography. Data was analyzed following the population approach and using the software Phoenix® NLMETM Version 7.0 software (Certara USA, Inc., Princeton, NJ, USA). From 34 patients, a total of 354 afatinib plasma concentration values were available for the population PK analysis. Significant covariates in the population PK model included aspartate aminotransferase and creatinine clearance on CL/F, and age and body mass index on V/F. Results of simulation based on final PK model indicated that hepatic impairment had a significant effect on afatinib levels in plasma after multiple dosing. Afatinib trough plasma concentrations on day 8 were higher in patients with adverse events of grade 3 or higher. The population PK analysis showed that hepatic impairment affected afatinib PK parameters and contributed to the high inter-patient variability and high plasma concentrations of afatinib following multiple treatments.

Determination of tyrosine kinase inhibitor afatinib in rat plasma using LC-MS/MS and its application to in vivo pharmacokinetic studies of afatinib liposomes.

A sensitive quantitative liquid chromatography-tandem mass spectrometry assay for afatinib in rat plasma was developed and validated using afatinib dimaleate as a standard. The analyte was determined to be ionized using the positive ion multiple reaction monitoring mode through electrospraying on an AB Sciex Triple Quad™ 4500 system. Protein precipitation was used for sample preparation, and an Agilent Eclipse XDB-CN column (100 × 2.1 mm, 3.5 µm) was applied for chromatographic separation. The mobile phase was water and methanol (15:85, v/v) containing 0.1% formic acid with a flow rate of 0.5 mL/min. The linear range was 0.5-200 ng/mL, with r2 = 0.9994 ± 0.0004 calculated from linear regression, with 1/x2 as the weighting factor for the calibration. The average recovery of the plasma samples was stable and reproducible. The analyte is sufficiently stable for handling and analysis. The pharmacokinetic study and comparison were performed by analyzing plasma concentrations in rats administered afatinib solution or prepared afatinib liposomes using the developed determination method. The Cmax of the afatinib liposomes was nearly 400-fold higher than that of the afatinib solution. These results indicate that liposome-encapsulation protected afatinib from endogenous protein binding, thereby reducing the risk of idiosyncratic drug reactions by protein adducts. Thus, Afatinib liposomes seem to be a promising strategy for the treatment of non-small cell lung cancer.

Effects of pharmacokinetics-related genetic polymorphisms on the side effect profile of afatinib in patients with non-small cell lung cancer.

OBJECTIVES: Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) represent the first-line treatment for patients with advanced EGFR mutation-positive non-small-cell lung cancer. Afatinib is a second-generation EGFR-TKI with excellent therapeutic effects. However, severe diarrhea and skin disorders are observed at high frequencies, often leading to treatment interruption because of low quality of life (QOL). The relationship between individual variations and the onset of these side effects remains to be elucidated. This study aimed to reveal the association among these side effects, pharmacokinetics, and related genetic polymorphisms. MATERIALS AND METHODS: In total, 33 patients were recruited between July 2014 and June 2017. Afatinib plasma concentrations were measured at day 9 when the concentrations reached a steady state (early phase) and when the prescription dose was stable for more than 1 month (stable phase). We analyzed single nucleotide polymorphisms in the genes ATP-binding cassette sub-family B member 1 (ABCB1), ABCG2, and flavin-containing monooxygenase 3. RESULTS: The incidences of both diarrhea and acneiform eruption were greater than 80%. Afatinib plasma concentration and the severity of diarrhea in the early phase were correlated. Pharmacokinetics-related genetic polymorphisms influenced the severity of diarrhea. Particularly, the afatinib plasma concentration was higher and diarrhea was more severe in patients carrying the A allele of ABCG2 C421A. Onset of side effects, genetic polymorphisms, and diarrhea in the maintenance phase or acneiform eruption in the early or maintenance phases were not correlated. The severity of diarrhea is influenced by drug plasma concentrations in the early phase and genetic polymorphisms related to afatinib pharmacokinetics. CONCLUSION: Particular genetic polymorphisms can be screened before afatinib administration and the dose adapted to individual patients can be controlled, leading to reduced side effects, improved QOL, and better patient compliance to maintain the therapeutic effects.

Phase Ib Study of High-dose Intermittent Afatinib in Patients With Advanced Solid Tumors.

BACKGROUND: The present phase Ib study assessed the maximum tolerated dose (MTD), safety, pharmacokinetics, and antitumor activity of high-dose intermittent (HDI) afatinib monotherapy for patients with advanced solid tumors. The planned focus was patients with epidermal growth factor receptor (EGFR) T790M+ non-small-cell lung cancer (NSCLC). MATERIALS AND METHODS: Eligible patients had histologically confirmed advanced solid tumors that were unsuitable for, or unresponsive to, standard therapy. The study used a 3+3 design with a starting dose of 90 mg/d for 3 days every 14 days (28-day cycles) and incremental dose escalations to 200 mg/d. RESULTS: Thirty-five patients (18 with NSCLC) were treated (6 at 90 mg; 3 at 120 mg; 9 at 150 mg; 11 at 160 mg; and 6 at 200 mg). One patient in the 90-mg cohort (grade 3 rash) and 2 patients in the 200-mg cohort (grade 3 diarrhea; grade 3 mucositis) experienced a dose-limiting toxicity. The MTD was 160 mg. The most common treatment-related adverse events were diarrhea (total, 88.6%; grade 3, 14.3%), rash/acne (total, 62.9%; grade 3, 2.9%), and fatigue (total, 40.0; grade 3, 0%). The maximum afatinib plasma concentration at the MTD was 313 ng/mL, exceeding the in vitro IC50 (inhibitor concentration decreased by one half) range for T790M inhibition. The trough levels suggested no systematic change in afatinib plasma concentrations during long-term treatment at this dosing schedule. Of the 13 T790M+ NSCLC patients, 1 achieved an objective response (7.7%). CONCLUSION: HDI afatinib was feasible and tolerable and could potentially be further explored for NSCLC indications, including patients with central nervous system disease, rare EGFR mutations, or T790M+ NSCLC intolerant of third-generation EGFR tyrosine kinase inhibitors.

A phase I study to assess afatinib in combination with carboplatin or with carboplatin plus paclitaxel in patients with advanced solid tumors.

PURPOSE: Afatinib, an irreversible ErbB family blocker, has demonstrated preclinical antitumor activity with chemotherapy. METHODS: As part of a phase I trial in patients with advanced solid tumors (NCT00809133; 3 + 3 dose-escalation design), we determined the maximum tolerated dose (MTD) of afatinib with carboplatin (A/C) or with carboplatin plus paclitaxel (A/C/P). Starting doses: afatinib 20 mg/day, carboplatin AUC6 (A/C) with paclitaxel 175 mg/m2 (A/C/P) (chemotherapy: Day 1 of 21-day cycles). The primary objective was to determine the MTDs; safety, pharmacokinetics and antitumor activity were also evaluated. RESULTS: Thirty-eight patients received A/C (n = 12) or A/C/P (n = 26). No dose-limiting toxicities (DLTs) were reported with A(20 mg)/C(AUC6). One patient experienced DLT in the A(40 mg)/C(AUC6) cohort (grade 3 acneiform rash); A(40 mg)/C(AUC6) was determined as the recommended phase II dose (RP2D) for A/C. Two patients each had DLTs with A(20 mg/day)/C(AUC6)/P(175 mg/m2): fatigue, infection, diarrhea, small intestine hemorrhage, dehydration, renal impairment, neutropenic sepsis (n = 1), mucositis (n = 1); A(40 mg)/C(AUC5)/P(175 mg/m2): febrile neutropenia (n = 1), mucositis, fatigue (n = 1); and A(30 mg)/C(AUC5)/P(175 mg/m2): stomatitis (n = 1), mucositis (n = 1). No DLT was observed with A(20 mg)/C(AUC5)/P(175 mg/m2), determined as the RP2D for A/C/P. The most frequent drug-related adverse events were (A/C; A/C/P): rash (75%; 73%), fatigue (67%; 69%), and diarrhea (58%; 88%). Drug plasma concentrations were similar between cycles, suggesting no drug-drug interactions. Objective response rates in these heavily pretreated patients were A/C, 3/12 (25%); A/C/P, 5/26 (19%). CONCLUSIONS: Afatinib 40 mg/day (approved monotherapy dose) with carboplatin AUC6, and afatinib 20 mg/day with carboplatin AUC5 and paclitaxel 175 mg/m2 demonstrated manageable safety and antitumor activity. Afatinib > 20 mg/day in the triple combination was not well tolerated.

Perspectives on window of opportunity trials in head and neck cancer: lessons from the EORTC 90111-24111-NOCI-HNCG study.

Assessing tumour response using a traditional phase I, II and III trial approach is not without limitations, particularly when targeted therapies are involved. Window of opportunity trials, performed presurgically but differing from neoadjuvant studies, were developed in an attempt to overcome the limitations of the traditional approach. A recent window of opportunity trial, the EORTC 90111-24111-NOCI-HNCG study, evaluated afatinib in treatment-naive patients with squamous cell carcinoma of the head and neck. While this study was the first to demonstrate the activity of afatinib in this setting and to define its potential predictive biomarkers, it also highlighted the challenges associated with the window of opportunity trial design, including the impact of patient selection, tumour site, and other organisational issues. This report details the key learnings from the EORTC 90111-24111-NOCI-HNCG study and provides recommendations to overcome the challenges of this particular trial design.