Therapeutic impact of BET inhibitor BI 894999 treatment: backtranslation from the clinic.

BACKGROUND: BET inhibitors have been tested in several clinical trials where, despite encouraging preclinical results, substantial clinical benefit in monotherapy remains limited. This work illustrates the translational challenges and reports new data around the novel BET inhibitor, BI 894999. At clinically achievable concentrations, mechanistic studies were carried out to study pathway modulation and rational drug combinations. METHODS: BRD-NUT fusions are oncogenic drivers in NUT carcinoma (NC). The effects of BI 894999 on proliferation, chromatin binding and pathway modulation were studied in NC in vitro. These studies were complemented by efficacy studies either as a single agent or in combination with the clinical p300/CBP inhibitor CCS1477. RESULTS: Based on the modelling of preclinical and clinical data, we proposed and implemented a new clinical scheduling regimen. This led to plasma levels sufficient to fully dislodge BRD-NUT from chromatin and to sustained and pronounced pharmacodynamic (PD) modulation of HEXIM1 and HIST2H2BF. Platelet counts in patient blood samples were improved compared to previous schedules. Rational combination studies of BI 894999 performed at clinically meaningful concentrations led to tumour regressions in all NC xenograft models tested. CONCLUSIONS: BI 894999 holds significant potential as a combination drug and CCS1477 p300/CBP inhibitor is a promising partner for future clinical trials.

Bioequivalence and adhesion evaluation of transdermal clonidine following a change in excipient supplier.

OBJECTIVE: To evaluate the bioequivalence (BE), safety, tolerability, and adhesion of Oppanol® polyisobutylene (PIB)-containing transdermal therapeutic system (TTS) formulation (test treatment, T) with VistanexTM PIB-containing TTS formulation (reference treatment, R) of clonidine. METHODS: This randomized, double-blind, 2-way crossover study comprised a 7-day treatment with 0.3 mg clonidine/24 h (T1/R1), a 7-day washout, and another 7-day treatment (R1/T1) period. After a 3-day washout period, subjects used T2 and R2 (each 0.1 mg clonidine/24 h) simultaneously in the 7-day adhesion phase. Primary endpoints were AUC0-168 and Cavg. Secondary endpoints were AUC0-∞ and Cmax. Additional endpoints included adhesion properties for all phases. For the primary endpoint, the geometric mean (gMean) ratios for test/reference treatment were calculated with BE defined as 90% confidence interval (CI) between 80 and 125%. RESULTS: 58 subjects (mean age, 41.3 years) received treatment (T1/R1, n = 29; R1/T1, n = 29); 55 completed the adhesion phase. BE criteria were met for the primary and secondary endpoints. Adjusted gMean ratios for T1/R1 were 102.3% (90% CI: 95.7%, 109.4%) for AUC0-168; 104.3% (90% CI: 98.4%, 110.5%) for Cavg; 102.8% (90% CI: 97.3%, 108.6%) for AUC0-∞; and 104.0% (90% CI: 98.2%, 110.3%) for Cmax. Mean adhesion was greater than 90% for all four patch types when data from all assessment times were included. Most frequently reported adverse events were general disorders and local irritation. CONCLUSIONS: Clonidine Oppanol® PIB-containing TTS formulation was bioequivalent to VistanexTM PIB-containing TTS formulation and had similar adhesive properties. Both doses and formulations of clonidine-TTS were well tolerated.

Phase I study of afatinib combined with nintedanib in patients with advanced solid tumours.

BACKGROUND: This Phase I study evaluated continuous- and intermittent-dosing (every other week) of afatinib plus nintedanib in patients with advanced solid tumours. METHODS: In the dose-escalation phase (n=45), maximum tolerated doses (MTDs) were determined for continuous/intermittent afatinib 10, 20, 30 or 40 mg once daily plus continuous nintedanib 150 or 200 mg twice daily. Secondary objectives included safety and efficacy. Clinical activity of continuous afatinib plus nintedanib at the MTD was further evaluated in an expansion phase (n=25). RESULTS: The most frequent dose-limiting toxicities were diarrhoea (11%) and transaminase elevations (7%). Maximum tolerated doses were afatinib 30 mg continuously plus nintedanib 150 mg, and afatinib 40 mg intermittently plus nintedanib 150 mg. Treatment-related adverse events (mostly Grade⩽3) included diarrhoea (98%), asthenia (64%), nausea (62%) and vomiting (60%). In the dose-escalation phase, two patients had partial responses (PRs) and 27 (60%) had stable disease (SD). In the expansion phase, one complete response and three PRs were observed (all non-small cell lung cancer), with SD in 13 (52%) patients. No pharmacokinetic interactions were observed. CONCLUSIONS: MTDs of continuous or intermittent afatinib plus nintedanib demonstrated a manageable safety profile with proactive management of diarrhoea. Antitumour activity was observed in patients with solid tumours.

Phase Ia dose-escalation trial with the BET protein inhibitor BI 894999 in patients with advanced or metastatic solid tumours.

BACKGROUND: Bromodomain and extraterminal domain (BET) inhibitors have demonstrated efficacy in solid tumours and haematological malignancies. BI 894999 is a novel oral BET inhibitor that has demonstrated potent antitumour activity in preclinical studies. PATIENTS AND METHODS: 1367.1 was an open-label, Phase Ia/Ib dose-finding study evaluating BI 894999 once daily in patients with advanced solid tumours (Schedule A: 0.2, 0.5, 1.0, 1.5, 2.0, and 5.0 mg, Days 1-21/21-d cycle; Schedule B: 1.5, 2.0, and 2.5 mg, Days 1-15/21-d cycle; Schedule C: loading dose 5.0, 6.0, or 7.0 mg on Day 1 followed by maintenance dose 2.5, 3.0, or 3.5 mg, Days 2-7 and 15-21/28-d cycle); 77 patients were enrolled. NCT02516553. RESULTS: Grade ≥3 dose-limiting toxicities (DLTs) were reported in 8/21, 5/25, and 9/31 patients for Schedules A, B, and C, respectively. Thrombocytopenia was reported as a DLT in 28.6%, 4.8%, and 9.7% for Schedules A, B, and C, respectively. Other DLTs occurring in ≥1 patient were troponin T increase (13.6%), hypophosphataemia (4.5%), and elevated creatine phosphokinase (3.0%). Disease control was achieved in 23.8%, 24.0%, and 29.0% of patients for Schedules A, B, and C, respectively. A partial response was achieved in 9.5% and 4% of patients with Schedules A and B, respectively. The best response with Schedule C was stable disease. CONCLUSION: The 1.5, 2.5, and 6.0/3.0 mg doses in Schedules A, B, and C, respectively, were declared as maximum tolerated dose. Based on the strength of these data, BI 894999 was further evaluated in a Phase Ib trial.

A Drug-Drug Interaction Study to Investigate the Effect of Nintedanib on the Pharmacokinetics of Microgynon (Ethinylestradiol and Levonorgestrel) in Female Patients with Systemic Sclerosis-Associated Interstitial Lung Disease.

BACKGROUND AND OBJECTIVES: Nintedanib is a tyrosine kinase inhibitor approved for the treatment of systemic sclerosis-associated interstitial lung disease (SSc-ILD), idiopathic pulmonary fibrosis, and other chronic fibrosing ILDs with a progressive phenotype. As nintedanib may cause foetal harm, patients taking nintedanib should avoid pregnancy. The objective of this study was to investigate the effect of nintedanib co-administration on the pharmacokinetics of Microgynon (ethinylestradiol and levonorgestrel) in female patients with SSc-ILD. METHODS: This was an open-label, two-period, fixed-sequence, drug-drug interaction study. Female patients with SSc and ≥ 10% extent of fibrotic ILD on a high-resolution computed tomography scan were eligible to participate. In Period 1, patients received one Microgynon tablet (ethinylestradiol 30 µg and levonorgestrel 150 µg) ≥ 3 days before the first administration of nintedanib in Period 2. In Period 2, patients received one Microgynon tablet following intake of nintedanib 150 mg twice daily for ≥ 10 consecutive days. The primary pharmacokinetic endpoints were the areas under the plasma concentration-time curve of ethinylestradiol and levonorgestrel over the time interval from 0 to the last quantifiable data point (AUC0-tz) and the maximum measured concentrations of ethinylestradiol and levonorgestrel in plasma (Cmax). The secondary pharmacokinetic endpoint was the area under the plasma concentration-time curve of ethinylestradiol and levonorgestrel over the time interval from 0 extrapolated to infinity (AUC0-∞). The relative exposures of ethinylestradiol and levonorgestrel when administered alone and in combination with nintedanib were assessed using an ANOVA model. RESULTS: Seventeen patients were treated. Pharmacokinetic data from 15 patients were analysed. Plasma concentration-time profiles of ethinylestradiol and levonorgestrel were similar following administration of Microgynon before and after administration of nintedanib for ≥ 10 consecutive days. Adjusted geometric mean (gMean) ratios [90% confidence intervals (CIs)] for AUC0‒tz (101.4% [92.8, 110.7]) and AUC0‒∞ (101.2% [94.0, 109.1]) indicated that there was no difference in total ethinylestradiol exposure when Microgynon was administered before or after administration of nintedanib. The adjusted gMean ratio for Cmax of ethinylestradiol (116.7% [90% CI 107.6, 126.5]) indicated an increase in peak exposure in the presence of nintedanib. Adjusted gMean ratios [90% CIs] for AUC0-tz (96.4% [91.5, 101.6]) and Cmax (100.9% [89.9, 113.2]) indicated that there was no difference in total or peak levonorgestrel exposure when Microgynon was administered before or after administration of nintedanib. The adjusted gMean ratio for AUC0‒∞ of levonorgestrel indicated a decrease in total exposure in the presence of nintedanib (88.1% [90% CI 80.0, 97.0]). CONCLUSION: Pharmacokinetic data indicate that there is no relevant effect of nintedanib on plasma exposure to ethinylestradiol and levonorgestrel in female patients with SSc-ILD. TRIAL REGISTRATION: Clinicaltrials.gov NCT03675581.

Pharmacokinetics and metabolism of BIBF 1120 after oral dosing to healthy male volunteers.

The pharmacokinetics and metabolism of BIBF 1120, an oral triple angiokinase inhibitor targeting vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR), and fibroblast growth factor receptor (FGFR), were studied in healthy male volunteers (n = 8) who had received a single oral dose of 100 mg [(14)C]-radiolabelled BIBF 1120 administered as solution. BIBF 1120 was well-tolerated and rapidly absorbed; median time to reach maximum plasma concentrations was 1.3 h and gMean terminal half-life was 13.7 h. A relatively high apparent total body clearance and volume of distribution possibly indicated a high tissue distribution. Plasma concentrations of BIBF 1120 plus carboxylate metabolite BIBF 1202 were lower than the total [(14)C]-radioactivity in plasma, indicating presence of additional metabolites. Total recovery in excreta was 94.7% 1 week post-dose; mass balance was considered complete after 96 h. BIBF 1120 and metabolites were mainly excreted via faeces. The major metabolic pathway for BIBF 1120 was methyl ester cleavage to BIBF 1202. Subsequently, the free carboxyl group of BIBF 1202 was glucuronidated to 1-O-acylglucuronide. Pathways of minor importance were oxidative N-demethylation to yield BIBF 1053, and oxidation of the piperazine moiety and conjugation. Glucuronidation of the parent drug and formylation of the secondary aliphatic amine of the piperazine ring played a minor role.

Clinical Pharmacokinetics and Pharmacodynamics of Nintedanib.

Nintedanib is an oral, small-molecule tyrosine kinase inhibitor approved for the treatment of idiopathic pulmonary fibrosis and patients with advanced non-small cell cancer of adenocarcinoma tumour histology. Nintedanib competitively binds to the kinase domains of vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF) and fibroblast growth factor (FGF). Studies in healthy volunteers and in patients with advanced cancer have shown that nintedanib has time-independent pharmacokinetic characteristics. Maximum plasma concentrations of nintedanib are reached approximately 2-4 h after oral administration and thereafter decline at least bi-exponentially. Over the investigated dose range of 50-450 mg once daily and 150-300 mg twice daily, nintedanib exposure increases are dose proportional. Nintedanib is metabolised via hydrolytic ester cleavage, resulting in the formation of the free acid moiety that is subsequently glucuronidated and excreted in the faeces. Less than 1% of drug-related radioactivity is eliminated in urine. The terminal elimination half-life of nintedanib is about 10-15 h. Accumulation after repeated twice-daily dosing is negligible. Sex and renal function have no influence on nintedanib pharmacokinetics, while effects of ethnicity, low body weight, older age and smoking are within the inter-patient variability range of nintedanib exposure and no dose adjustments are required. Administration of nintedanib in patients with moderate or severe hepatic impairment is not recommended, and patients with mild hepatic impairment should be monitored closely and the dose adjusted accordingly. Nintedanib has a low potential for drug-drug interactions, especially with drugs metabolised by cytochrome P450 enzymes. Concomitant treatment with potent inhibitors or inducers of the P-glycoprotein transporter can affect the pharmacokinetics of nintedanib. At an investigated dose of 200 mg twice daily, nintedanib does not have proarrhythmic potential.

Effects of Ketoconazole and Rifampicin on the Pharmacokinetics of Nintedanib in Healthy Subjects.

BACKGROUND: Nintedanib is a substrate for p-glycoprotein which can impact bioavailability. We investigated the effects of ketoconazole, a p-glycoprotein inhibitor, and rifampicin, a p-glycoprotein inducer, on the pharmacokinetics of nintedanib. METHODS: In the ketoconazole study, 34 healthy subjects received nintedanib 50 mg orally alone and 1 h after the last dose of ketoconazole given orally at a dose of 400 mg once daily for 3 days in 1 of 2 randomized sequences. In the rifampicin study, 26 subjects received nintedanib 150 mg orally alone and the morning after the last dose of rifampicin given orally at a dose of 600 mg once daily for 7 days. The primary objective was to determine the relative bioavailability of nintedanib administered following multiple doses of ketoconazole or rifampicin versus alone, based on AUC from time 0 extrapolated to infinity (AUC0-∞) and maximum concentration (Cmax) calculated using an analysis of variance. Geometric mean ratios and 2-sided 90% CIs were calculated. RESULTS: Exposure to nintedanib increased when it was administered following ketoconazole versus alone (AUC0-∞: geometric mean ratio, 160.5% [90% CI, 148.2-173.7]; Cmax: geometric mean ratio, 179.6% [90% CI, 157.6-204.8]) and decreased when it was administered following rifampicin versus alone (AUC0-∞: geometric mean ratio, 50.1% [90% CI, 47.2-53.3]; Cmax: geometric mean ratio, 59.8% [90% CI, 53.8-66.4]). The time to reach Cmax (tmax) and half-life (t½) of nintedanib were unaffected by co-administration of ketoconazole or rifampicin. CONCLUSIONS: Exposure to nintedanib is increased by co-administration of ketoconazole and decreased by co-administration of rifampicin, likely due to effects on bioavailability of the absorbed fraction. ClinicalTrials.govidentifiers:NCT01679613, NCT01770392.

Pharmacokinetics of Nintedanib in Subjects With Hepatic Impairment.

Nintedanib is an intracellular inhibitor of tyrosine kinases used in the treatment of non-small cell lung cancer and idiopathic pulmonary fibrosis (IPF). This phase 1 open-label study investigated the influence of mild and moderate hepatic impairment on the pharmacokinetics (PK), safety, and tolerability of nintedanib following oral administration of a single 100-mg dose. Subjects with hepatic impairment classified as Child-Pugh A (mild hepatic impairment) or Child-Pugh B (moderate hepatic impairment) were eligible. The control group comprised healthy matched subjects. Primary end points were Cmax and AUC0-∞ of nintedanib. Thirty-three subjects received nintedanib (8 in each of the Child-Pugh A and Child-Pugh B groups and 17 controls). The shape of the plasma concentration-time curve for nintedanib was similar between Child-Pugh A or B and healthy subjects. Nintedanib exposure was ∼2-fold higher in Child-Pugh A subjects and ∼8-fold higher in Child-Pugh B subjects than in healthy subjects. Adverse events were reported in 3 Child-Pugh B subjects (37.5%), no Child-Pugh A subjects, and 3 healthy subjects (17.6%). In conclusion, exposure to nintedanib was higher in Child-Pugh A and B subjects than in matched healthy subjects. A single dose of nintedanib 100 mg had an acceptable safety and tolerability profile in subjects with hepatic impairment. Results of this dedicated phase 1 study are in line with exploratory investigations into the PK of nintedanib in patients with advanced solid tumors or IPF and hepatic impairment.

Effect of Steady-State Faldaprevir on Pharmacokinetics of Atorvastatin or Rosuvastatin in Healthy Volunteers: A Prospective Open-Label, Fixed-Sequence Crossover Study.

Faldaprevir (FDV) is a potent, orally administered inhibitor of hepatitis C virus protease. It inhibits multiple cytochrome P-450 enzymes and multiple membrane transporters. The objective of this study was to evaluate the effect of steady-state faldaprevir on the pharmacokinetics (PK) of a single dose of atorvastatin or rosuvastatin. In this single-center, open-label, fixed-sequence crossover study, 33 healthy adult male and female volunteers were given either atorvastatin 10 mg (n = 16) or rosuvastatin 10 mg (n = 17) on day 1. Subjects subsequently received 240 mg twice daily of faldaprevir (loading dose) on day 5, followed by 240 mg faldaprevir once daily from day 6 to day 10, with an additional single dose of atorvastatin (10 mg) or rosuvastatin (10 mg) given on day 10. PK samples for the statins were collected on days 1-3 and days 10-12. Concomitant administration with faldaprevir led to approximately 9-fold and 34-fold increases in AUC0-∞ and Cmax , respectively, of atorvastatin and approximately 15-fold and 33-fold increases in AUC0-∞ and Cmax , respectively, of rosuvastatin, compared with the statins given alone. Exposure to the major metabolites (ortho-hydroxyatorvastatin and N-desmethylrosuvastatin) was increased to a similar magnitude as that of the parent compounds. The marked drug-drug interaction observed is most likely related to the inhibitory effects of faldaprevir on transporters, particularly hepatic uptake transporters such as OTAP1B1 and OATP1B3. Given the significant increase in exposure to statins in healthy volunteers, coadministration of faldaprevir with statins should be avoided.

Pharmacokinetic Properties of Nintedanib in Healthy Volunteers and Patients With Advanced Cancer.

Nintedanib, a triple angiokinase inhibitor, has undergone clinical investigation for the treatment of solid tumors and idiopathic pulmonary fibrosis. Nintedanib (Vargatef® ) plus docetaxel is approved in the EU for the treatment of patients with adenocarcinoma non-small cell lung cancer (NSCLC) after first-line chemotherapy, and as monotherapy (Ofev® ) in the United States and EU for the treatment of patients with idiopathic pulmonary fibrosis. Pharmacokinetics (PK) of nintedanib after oral single and multiple doses and intravenous (IV) administration were assessed using 3 data sets: (1) an absolute bioavailability trial that enrolled 30 healthy volunteers; (2) a pooled data analysis of 4 studies that enrolled a total of 107 healthy volunteers; and (3) a pooled data analysis of 4 studies that enrolled a total of 149 patients with advanced cancer. In the absolute bioavailability trial of healthy volunteers, nintedanib showed a high total clearance (geometric mean 1390 mL/min) and a high volume of distribution at steady state (Vss  = 1050 L). Urinary excretion of IV nintedanib was about 1% of dose; renal clearance was about 20 mL/min and therefore negligible. There was no deviation from dose proportionality after IV administration in the dose range tested. Absolute bioavailability of oral nintedanib (100 mg capsule) relative to IV dosing (4-hour infusion, 6 mg) was slightly below 5%. Nintedanib was quickly absorbed after oral administration. It underwent rapid and extensive first-pass metabolism and followed at least biphasic disposition kinetics. In advanced cancer patients, steady state was reached at the latest at 7 days for twice-daily dosing. Nintedanib's PK was time-independent; accumulation after repeated administration was negligible.

Volasertib Versus Chemotherapy in Platinum-Resistant or -Refractory Ovarian Cancer: A Randomized Phase II Groupe des Investigateurs Nationaux pour l'Etude des Cancers de l'Ovaire Study.

PURPOSE: Volasertib is a potent and selective cell-cycle kinase inhibitor that induces mitotic arrest and apoptosis by targeting Polo-like kinase. This phase II trial evaluated volasertib or single-agent chemotherapy in patients with platinum-resistant or -refractory ovarian cancer who experienced failure after treatment with two or three therapy lines. PATIENTS AND METHODS: Patients were randomly assigned to receive either volasertib 300 mg by intravenous infusion every 3 weeks or an investigator's choice of single-agent, nonplatinum, cytotoxic chemotherapy. The primary end point was 24-week disease control rate. Secondary end points included best overall response, progression-free survival (PFS), safety, quality of life, and exploratory biomarker analyses. RESULTS: Of the 109 patients receiving treatment, 54 received volasertib and 55 received chemotherapy; demographics were well balanced. The 24-week disease control rates for volasertib and chemotherapy were 30.6% (95% CI, 18.0% to 43.2%) and 43.1% (95% CI, 29.6% to 56.7%), respectively, with partial responses in seven (13.0%) and eight (14.5%) patients, respectively. Median PFS was 13.1 weeks and 20.6 weeks for volasertib and chemotherapy (hazard ratio, 1.01; 95% CI, 0.66 to 1.53). Six patients (11%) receiving volasertib achieved PFS fore more than 1 year, whereas no patient receiving chemotherapy achieved PFS greater than 1 year. No relationship between the expression of the biomarkers tested and their response was determined. Patients treated with volasertib experienced more grade 3 and 4 drug-related hematologic adverse events (AEs) and fewer nonhematologic AEs than did patients receiving chemotherapy. Discontinuation resulting from AEs occurred in seven (13.0%) and 15 (27.3%) patients in the volasertib and chemotherapy arms, respectively. Both arms showed similar effects on quality of life. CONCLUSION: Single-agent volasertib showed antitumor activity in patients with ovarian cancer. AEs in patients receiving volasertib were mainly hematologic and manageable.

Pharmacokinetic drug interactions of afatinib with rifampicin and ritonavir.

BACKGROUND AND OBJECTIVE: Afatinib is a potent, irreversible, ErbB family blocker in clinical development for the treatment of advanced non-small cell lung cancer, metastatic head and neck cancer, and other solid tumours. As afatinib is a substrate for the P-glycoprotein (P-gp) pump transporter the three studies presented here investigated the pharmacokinetics of afatinib in the presence of a potent inhibitor (ritonavir) or inducer [rifampicin (rifampin)] of P-gp. METHODS: We conducted phase I, open-label, single-centre studies in healthy male volunteers who received a single once-daily oral dose of afatinib (20 or 40 mg) together with either ritonavir or rifampicin; two studies had a randomised, two- and three-way crossover design and the third was a non-randomised, two-period sequential study. RESULTS: When afatinib 20 mg was administered 1 h after ritonavir, afatinib geometric mean (gMean) maximum plasma concentration (C max) and area under the plasma concentration-time curve from time zero to infinity (AUC∞) increased by 38.5 and 47.6 %, respectively. Coadministration of ritonavir either simultaneously or 6 h later than afatinib 40 mg resulted in minimal increase in the afatinib gMean C max and AUC∞ (4.1 and 18.6 % for simultaneous administration with AUC∞ not completely within the bioequivalence limits; 5.1 and 10.8 % for timed administration within the bioequivalence limits). Administration of afatinib 40 mg in the presence of rifampicin led to reduction in C max and AUC∞ by 21.6 and 33.8 %, respectively. In all studies, P-gp modulation mainly affected the extent of absorption of afatinib; there was no change in the terminal elimination half-life. The overall safety profile of afatinib was acceptable. CONCLUSION: Coadministration of potent P-gp modulators had no clinically relevant effect on afatinib exposure. Effects of potent P-gp inhibitors were minimal at higher afatinib doses and can be readily managed by the timing of concomitant therapy. As afatinib is not a relevant modulator or substrate of cytochrome P450 enzymes, the drug-drug interaction potential is considered to be low.

Afatinib pharmacokinetics and metabolism after oral administration to healthy male volunteers.

PURPOSE: To investigate the pharmacokinetics, metabolism and tolerability of afatinib (BIBW 2992), an oral irreversible ErbB family blocker, in healthy male volunteers. METHODS: In this open-label, single-center study, 8 healthy male volunteers received a single oral dose of 15 mg [(14)C]-radiolabeled afatinib (equivalent to 22.2 mg of the dimaleinate salt) as a solution. Blood, urine and fecal samples were collected for at least 96 hours (h) after dosing. Plasma and urine concentrations of afatinib were analyzed using high-performance liquid chromatography-tandem mass spectrometry. [(14)C]-radioactivity levels in plasma, whole blood, urine and feces were measured by liquid scintillation counting methods. Metabolite patterns were assessed by high-performance liquid chromatography. RESULTS: [(14)C]-radioactivity was mainly excreted via feces (85.4%). Overall recovery of [(14)C]-radioactivity was 89.5%, indicative of a complete mass balance. Afatinib was slowly absorbed, with maximum plasma concentrations achieved at a median of 6 h after dosing, declining thereafter in a biexponential manner. The geometric mean terminal half-life of afatinib was 33.9 h in plasma and longer for [(14)C]-radioactivity in plasma and whole blood. Apparent total body clearance for afatinib was high (geometric mean 1,530 mL/min). The high volume of distribution (4,500 L) in plasma may indicate a high tissue distribution. Afatinib was metabolized to only a minor extent, with the main metabolite afatinib covalently bound to plasma proteins. Oxidative metabolism mediated via cytochrome P-450 was of negligible importance for the elimination of afatinib. Afatinib was well tolerated. CONCLUSIONS: Afatinib displayed a complete mass balance with the main route of excretion via feces. Afatinib undergoes minimal metabolism.