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Purpose Entrectinib is a central nervous system-active potent inhibitor of tropomyosin receptor kinase (TRK), with anti-tumor activity against neurotrophic NTRK gene fusion-positive tumors. This study investigates the pharmacokinetics of entrectinib and its active metabolite (M5) in pediatric patients and aims to understand whether the pediatric dose of 300 mg/m2 once daily (QD) provides an exposure that is consistent with the approved adult dose (600 mg QD). Methods Forty-three patients aged from birth to 22 years were administered entrectinib (250–750 mg/m2 QD) orally with food in 4-week cycles. Entrectinib formulations included capsules without acidulant (F1) and capsules with acidulant (F2B and F06). Results Although there was interpatient variability with F1, entrectinib and M5 exposures increased dose dependently. Lower systemic exposures were observed in pediatric patients receiving 400 mg/m2 QD entrectinib (F1) versus adults receiving either the same dose/formulation or the recommended flat dose of 600 mg QD (~ 300 mg/m2 for a 70 kg adult) due to suboptimal F1 performance in the pediatric study. The observed pediatric exposures following 300 mg/m2 QD entrectinib (F06) were comparable to those in adults receiving 600 mg QD. Conclusions Overall, the F1 formulation of entrectinib was associated with lower systemic exposure in pediatric patients compared with the commercial acidulant formulation (F06). Systemic exposures achieved in pediatric patients with the F06 recommended dose (300 mg/m2) were within the known efficacious range in adults, confirming the adequacy of the recommended dose regimen with the commercial formulation.

Background Entrectinib is a TRKA/B/C, ROS1, ALK tyrosine kinase inhibitor approved for the treatment of adults and children aged ≥12 years with NTRK fusion-positive solid tumors and adults with ROS1 fusion-positive non–small-cell lung cancer. We report an analysis of the STARTRK-NG trial, investigating the recommended phase 2 dose (RP2D) and activity of entrectinib in pediatric patients with solid tumors including primary central nervous system tumors. Methods STARTRK-NG (NCT02650401) is a phase 1/2 trial. Phase 1, dose-escalation of oral, once-daily entrectinib, enrolled patients aged Results At data cutoff, 43 patients, median age of 7 years, were response-evaluable. In phase 1, 4 patients experienced dose-limiting toxicities. The most common treatment-related adverse event was weight gain (48.8%). Nine patients experienced bone fractures (20.9%). In patients with fusion-positive tumors, ORR was 57.7% (95% CI 36.9-76.7), median duration of response was not reached, and median (interquartile range) duration of treatment was 10.6 months (4.2-18.4). Conclusions Entrectinib resulted in rapid and durable responses in pediatric patients with solid tumors harboring NTRK1/2/3 or ROS1 fusions.

1. Supplementary Figure 1. Illustration of tubes area detection as rectangles based on the bright field channel. 2. Supplementary Figure 2. Diarrhea severity during combination treatment with lumretuzumab (RO5479599), pertuzumab and paclitaxel in patients. 3. Full Unedited western blots of figures 2c and 2d

Combination of targeted therapies is expected to provide superior efficacy in the treatment of cancer either by enhanced antitumor activity or by preventing or delaying the development of resistance. Common challenges in developing combination therapies include the potential of additive and aggravated toxicities associated with pharmacologically related adverse effects. We have recently reported that combination of anti-HER2 and anti-HER3 antibodies, pertuzumab and lumretuzumab, along with paclitaxel chemotherapy in metastatic breast cancer, resulted in a high incidence of diarrhea that ultimately limited further clinical development of this combination. Here, we further dissected the diarrhea profile of the various patient dose cohorts and carried out in vitro investigations in human colon cell lines and explants to decipher the contribution and the mechanism of anti-HER2/3 therapeutic antibodies to intestinal epithelium malfunction. Our clinical investigations in patients revealed that while dose reduction of lumretuzumab, omission of pertuzumab loading dose, and introduction of a prophylactic antidiarrheal treatment reduced most severe adverse events, patients still suffered from persistent diarrhea during the treatment. Our in vitro investigations showed that pertuzumab and lumretuzumab combination treatment resulted in upregulation of chloride channel activity without indication of intestinal barrier disruption. Overall, our findings provide a mechanistic rationale to explore alternative of conventional antigut motility using medication targeting chloride channel activity to mitigate diarrhea of HER combination therapies. Mol Cancer Ther; 17(7); 1464–74. ©2018 AACR.

Purpose: This study investigated the safety, clinical activity, and target-associated biomarkers of lumretuzumab, a humanized, glycoengineered, anti-HER3 monoclonal antibody (mAb), in combination with the EGFR-blocking agents erlotinib or cetuximab in patients with advanced HER3-positive carcinomas.Experimental Design: The study included two parts: dose escalation and dose extension phases with lumretuzumab in combination with either cetuximab or erlotinib, respectively. In both parts, patients received lumretuzumab doses from 400 to 2,000 mg plus cetuximab or erlotinib according to standard posology, respectively. The effect of HRG mRNA and HER3 mRNA and protein expression were investigated in a dedicated extension cohort of squamous non–small cell lung cancer (sqNSCLC) patients treated with lumretuzumab and erlotinib.Results: Altogether, 120 patients were treated. One dose-limiting toxicity (DLT) in the cetuximab part and two DLTs in the erlotinib part were reported. The most frequent adverse events were gastrointestinal and skin toxicities, which were manageable. The objective response rate (ORR) was 6.1% in the cetuximab part and 4.2% in the erlotinib part. In the sqNSCLC extension cohort of the erlotinib part, higher tumor HRG and HER3 mRNA levels were associated with a numerically higher disease control rate but not ORR.Conclusions: The toxicity profile of lumretuzumab in combination with cetuximab and erlotinib was manageable, but only modest clinical activity was observed across tumor types. In the sqNSCLC cohort, there was no evidence of meaningful clinical benefit despite enriching for tumors with higher HRG mRNA expression levels. Clin Cancer Res; 23(18); 5406–15. ©2017 AACR.

Figure 1 Mean ({plus minus}SD) serum lumretuzumab profiles following multiple ascending doses from 100 mg up to 2000 mg Figure 2 Percentage change in standardized uptake value maximum from baseline as assessed by FDG-PET at (a) Cycle 1 Day 14 and (b) Cycle 4 Day 14 Table 1 Summary of baseline and change in HER3 expression measured by IHC in skin and tumor biopsy samples pre and post treatment with lumretuzumab Table 2 Summary of change in expression of HER3, HER2, EGFR and cMET in fresh tumor biopsies compared to primary archival samples Table 3 Peripheral blood immunophenotyping (T, B and NK cells and NK subsets) from patients dosed with 2000 mg lumretuzumab Table 4 Ex-vivo activation potential of peripheral NK lymphocytes for all patients at ba seline and following exposure to lumretuzumab in the 2000 mg dose cohort Table 5 Summary of tumor immune effector cell infiltration Table 6 Tumor response to treatment (RECIST)

Supplementary Table 1 Downregulation of HER3 membrane protein expression in skin biopsies following treatment with lumretuzumab and cetuximab or erlotinib Supplementary Table 2 Change of tumor biomarkers in tumor biopsies following treatment with lumretuzumab and cetuximab or erlotinib

Purpose: We evaluated biodistribution and tumor targeting of 89Zr-lumretuzumab before and during treatment with lumretuzumab, a human epidermal growth factor receptor 3 (HER3)–targeting monoclonal antibody.Experimental Design: Twenty patients with histologically confirmed HER3-expressing tumors received 89Zr-lumretuzumab and underwent positron emission tomography (PET). In part A, 89Zr-lumretuzumab was given with additional, escalating doses of unlabeled lumretuzumab, and scans were performed 2, 4, and 7 days after injection to determine optimal imaging conditions. In part B, patients were scanned following tracer injection before (baseline) and after a pharmacodynamic (PD)-active lumretuzumab dose for saturation analysis. HER3 expression was determined immunohistochemically in skin biopsies. Tracer uptake was calculated as standardized uptake value (SUV).Results: Optimal PET conditions were found to be 4 and 7 days after administration of 89Zr-lumretuzumab with 100-mg unlabeled lumretuzumab. At baseline using 100-mg unlabeled lumretuzumab, the tumor SUVmax was 3.4 (±1.9) at 4 days after injection. SUVmean values for normal blood, liver, lung, and brain tissues were 4.9, 6.4, 0.9 and 0.2, respectively. Saturation analysis (n = 7) showed that 4 days after lumretuzumab administration, tumor uptake decreased by 11.9% (±8.2), 10.0% (±16.5), and 24.6% (±20.9) at PD-active doses of 400, 800, and 1,600 mg, respectively, when compared with baseline. Membranous HER3 was completely downregulated in paired skin biopsies already at and above 400-mg lumretuzumab.Conclusions: PET imaging showed biodistribution and tumor-specific 89Zr-lumretuzumab uptake. Although, PD-active lumretuzumab doses decreased 89Zr-lumretuzumab uptake, there was no clear evidence of tumor saturation by PET imaging as the tumor SUV did not plateau with increasing doses. Clin Cancer Res; 23(20); 6128–37. ©2017 AACR.

Purpose: A first-in-human phase I study was conducted to characterize safety, efficacy, and pharmacokinetic (PK) and pharmacodynamic (PD) properties of lumretuzumab, a humanized and glycoengineered anti-HER3 monoclonal antibody, in patients with advanced cancer.Experimental Design: Twenty-five patients with histologically confirmed HER3-expressing tumors received lumretuzumab (100, 200, 400, 800, 1,600, and 2,000 mg) every two weeks (q2w) in 3+3 dose-escalation phase. In addition, 22 patients were enrolled into an extension cohort at 2,000 mg q2w.Results: There were no dose-limiting toxicities. Common adverse events (any grade) included diarrhea (22 patients, 46.8%), fatigue (21 patients, 44.7%), decreased appetite (15 patients, 31.9%), infusion-related reactions (13 patients, 27.7%), and constipation (10 patients, 21.3%). The peak concentration (Cmax) and area under the concentration–time curve up to the last measurable concentration (AUClast) of lumretuzumab increased more than dose proportionally from 100 mg up to 400 mg. Linear PK was observed with doses ≥400 mg q2w indicating target-mediated drug disposition saturation. Downregulation of HER3 membranous protein was observed in on-treatment tumor biopsies from 200 mg, and was maximal at and above 400 mg. An ex vivo assay demonstrated increased activation potential of peripheral NK lymphocytes with lumretuzumab compared with a non-glycoengineered anti-HER3 antibody. Ten patients (21.3%) had stable disease and remained on study at a median of 111 days (range, 80–225 days).Conclusions: Lumretuzumab was well tolerated and showed evidence of clinical activity. Linear serum PK properties and plateauing of PD effects in serial tumor biopsies indicate optimal biologically active doses of lumretuzumab from 400 mg onwards. Clin Cancer Res; 22(4); 877–85. ©2015 AACR.

Supplemental Figures and Tables

Figure 1 Mean ({plus minus}SD) serum lumretuzumab profiles following multiple ascending doses from 100 mg up to 2000 mg Figure 2 Percentage change in standardized uptake value maximum from baseline as assessed by FDG-PET at (a) Cycle 1 Day 14 and (b) Cycle 4 Day 14 Table 1 Summary of baseline and change in HER3 expression measured by IHC in skin and tumor biopsy samples pre and post treatment with lumretuzumab Table 2 Summary of change in expression of HER3, HER2, EGFR and cMET in fresh tumor biopsies compared to primary archival samples Table 3 Peripheral blood immunophenotyping (T, B and NK cells and NK subsets) from patients dosed with 2000 mg lumretuzumab Table 4 Ex-vivo activation potential of peripheral NK lymphocytes for all patients at ba seline and following exposure to lumretuzumab in the 2000 mg dose cohort Table 5 Summary of tumor immune effector cell infiltration Table 6 Tumor response to treatment (RECIST)

Supplementary Figure 1 Quantile plots of baseline membrane HER3 IRS score (A) and HER3 mRNA log expression (B) in baseline FFPE tumor biopsy samples from patients with known adeno- and squamous cell carcinoma histology Supplementary Figure 2 Quantile plots of baseline membrane HER3 immuno-reactive scores in fresh FFPE tumor biopsies from NSCLC patients with non-squamous or squamous histology Supplementary Figure 3 Quantile plots of baseline HRG mRNA log expression determined by qRT-PCR in FFPE tumor biopsies of adeno- and squamous cell carcinoma histology (data obtained using the HRG research assay) Supplementary Figure 4 Baseline HRG mRNA log expression in FFPE tumor biopsies, determined by qRT-PCR, in non-sqNSCLC and sqNSCLC (data obtained using the HRG prototype diagnostic assay). Dotted line indicates prior determined median HRG expression in sqNSCLC. Supplementary Figure 5 Best percentage change from baseline in sum of longest diameters of target lesions for patients in the dose escalation and extension phase of the cetuximab part (n = 38). Red bars indicate PD patients, blue bars SD patients, light green bars PR patients and dark green bars CR patients. Eleven patients were without target lesion assessment post baseline. Tumor type and lumretuzumab dose are indicated. * indicates patients who received previous EGFR-targeting therapy. a indicates a patient who received prior trastuzumab therapy. Supplementary Figure 6 Best percentage change from baseline in sum of longest diameters of target lesions for patients in the dose escalation phase and the two NRG1 fusion gene patients of the extension phase of the erlotinib part (n = 31). Red bars indicate PD patients, blue bars SD patients and green bars PR patients. Eight patients were without target lesion assessment post baseline. Tumor type and lumretuzumab dose are indicated. * indicates patients who received previous EGFR-targeting therapy. a indicates two patients with NRG1 gene fusion.

Entrectinib (ROZLYTREK®) is a CNS-active, potent, and selective inhibitor of ROS1, TRK A/B/C, and ALK kinase activity. It was recently approved for the treatment of ROS1-positive non-small cell lung cancer and NTRK gene fusion-positive solid tumors. The main objective of this analysis was to characterize the pharmacokinetics (PK) of entrectinib and its main active metabolite, M5. A total of 276 cancer patients receiving oral entrectinib were included in the analysis. A model-based population approach was used to characterize the PK profiles of both entities using NONMEM® 7.4. A joint model captures the PK of both entrectinib and M5. The effects of pH modifiers, formulation, weight, age, and sex on model parameters were assessed. Model performance was evaluated using visual predictive checks (VPCs). The absorption of entrectinib was best described using a sequential zero- and first-order absorption model and the disposition with one-compartment model for each entity with linear elimination. Moderate-to-high between-patient variability was estimated in model parameters (from 30.8% for the apparent clearance of entrectinib to 122% for the first-order absorption rate constant). Theory-based allometric scaling using body weight on clearances and volumes and a 28% lower relative bioavailability of the F1 formulation in pediatric patients were retained in the model. The VPC confirmed the good predictive performance of the PopPK model. A robust population PK model was built and qualified for entrectinib and M5, describing linear PK for both entities. This model was used to support the ROZLYTREK® new drug application.

Entrectinib is a selective inhibitor of ROS1/TRK/ALK kinases, recently approved for oncology indications. Entrectinib is predominantly cleared by cytochrome P450 (CYP) 3A4, and modulation of CYP3A enzyme activity profoundly alters the pharmacokinetics of both entrectinib and its active metabolite M5. We describe development of a combined physiologically based pharmacokinetic (PBPK) model for entrectinib and M5 to support dosing recommendations when entrectinib is co-administered with CYP3A4 inhibitors or inducers. A PBPK model was established in Simcyp® Simulator. The initial model based on in vitro–in vivo extrapolation was refined using sensitivity analysis and non-linear mixed effects modeling to optimize parameter estimates and to improve model fit to data from a clinical drug–drug interaction study with the strong CYP3A4 inhibitor, itraconazole. The model was subsequently qualified against clinical data, and the final qualified model used to simulate the effects of moderate to strong CYP3A4 inhibitors and inducers on entrectinib and M5 pharmacokinetics. The final model showed good predictive performance for entrectinib and M5, meeting commonly used predictive performance acceptance criteria in each case. The model predicted that co-administration of various moderate CYP3A4 inhibitors (verapamil, erythromycin, clarithromycin, fluconazole, and diltiazem) would result in an average increase in entrectinib exposure between 2.2- and 3.1-fold, with corresponding average increases for M5 of approximately 2-fold. Co-administration of moderate CYP3A4 inducers (efavirenz, carbamazepine, phenytoin) was predicted to result in an average decrease in entrectinib exposure between 45 and 79%, with corresponding average decreases for M5 of approximately 50%. The model simulations were used to derive dosing recommendations for co-administering entrectinib with CYP3A4 inhibitors or inducers. PBPK modeling has been used in lieu of clinical studies to enable regulatory decision-making.

SummaryBackground: Entrectinib is an oral, CNS-active, potent inhibitor of tyrosine receptor kinases A/B/C, tyrosine kinase ROS proto-oncogene 1, and anaplastic lymphoma kinase approved for use in patients with solid tumors. We describe 3 clinical studies, including one investigating the single/multiple dose pharmacokinetics of entrectinib in patients and two studies in healthy volunteers investigating the absorption/distribution/metabolism/excretion (ADME) of entrectinib, its relative bioavailability, and effect of food on pharmacokinetics. Methods: The patient study is open-label with dose-escalation and expansion phases. Volunteers received entrectinib (100–400 mg/m2, and 600–800 mg) once daily with food in continuous 28-day cycles. In the ADME study, volunteers received a single oral dose of [14C]entrectinib 600 mg. In the third study, volunteers received single doses of entrectinib 600 mg as the research and marketed formulations in the fasted state (Part 1), and the marketed formulation in the fed and fasted states (Part 2). Entrectinib and its major active metabolite M5 were assessed in all studies. Results: Entrectinib was absorbed in a dose-dependent manner with maximum concentrations at ~4 h postdose and an elimination half-life of ~20 h. Entrectinib was cleared mainly through metabolism and both entrectinib and metabolites were eliminated mainly in feces (minimal renal excretion). At steady-state, the M5-to-entrectinib AUC ratio was 0.5 (with 600 mg entrectinib research formulation in patients). The research and marketed formulations were bioequivalent and food had no relevant effect on pharmacokinetics. Conclusions: Entrectinib is well absorbed, with linear PK that is suitable for once-daily dosing, and can be taken with or without food.

BackgroundThis phase 1b study (NCT02323191) evaluated the safety, antitumor activity, pharmacokinetics, and pharmacodynamics of colony-stimulating factor-1 receptor-blocking monoclonal antibody (mAb) emactuzumab in combination with the programmed cell death-1 ligand (PD-L1)-blocking mAb atezolizumab in patients with advanced solid tumors naïve or experienced for immune checkpoint blockers (ICBs).MethodsEmactuzumab (500–1350 mg flat) and atezolizumab (1200 mg flat) were administered intravenously every 3 weeks. Dose escalation of emactuzumab was conducted using the 3+3 design up to the maximum tolerated dose (MTD) or optimal biological dose (OBD). Extension cohorts to evaluate pharmacodynamics and clinical activity were conducted in metastatic ICB-naive urothelial bladder cancer (UBC) and ICB-pretreated melanoma (MEL), non-small cell lung cancer (NSCLC) and UBC patients.ResultsOverall, 221 patients were treated. No MTD was reached and the OBD was determined at 1000 mg of emactuzumab in combination with 1200 mg of atezolizumab. Grade ≥3 treatment-related adverse events occurred in 25 (11.3%) patients of which fatigue and rash were the most common (14 patients (6.3%) each). The confirmed objective response rate (ORR) was 9.8% for ICB-naïve UBC, 12.5% for ICB-experienced NSCLC, 8.3% for ICB-experienced UBC and 5.6% for ICB-experienced MEL patients, respectively. Tumor biopsy analyses demonstrated increased activated CD8 +tumor infiltrating T lymphocytes (TILs) associated with clinical benefit in ICB-naïve UBC patients and less tumor-associated macrophage (TAM) reduction in ICB-experienced compared with ICB-naïve patients.ConclusionEmactuzumab in combination with atezolizumab demonstrated a manageable safety profile with increased fatigue and skin rash over usual atezolizumab monotherapy. A considerable ORR was particularly seen in ICB-experienced NSCLC patients. Increase ofCD8 +TILs under therapy appeared to be associated with persistence of a TAM subpopulation.

Background Emactuzumab is a monoclonal antibody against the colony-stimulating factor-1 receptor and targets tumor-associated macrophages (TAMs). This study assessed the safety, clinical activity, pharmacokinetics (PK) and pharmacodynamics (PD) of emactuzumab, as monotherapy and in combination with paclitaxel, in patients with advanced solid tumors. Patients and methods This open-label, phase Ia/b study comprised two parts (dose escalation and dose expansion), each containing two arms (emactuzumab, every 2 or 3weeks, as monotherapy or in combination with paclitaxel 80mg/m2 weekly). The dose-escalation part explored the maximum tolerated dose and optimal biological dose (OBD). The dose-expansion part extended the safety assessment and investigated the objective response rate. A PK/PD analysis of serial blood, skin and tumor biopsies was used to explore proof of mechanism and confirm the OBD. Results No maximum tolerated dose was reached in either study arm, and the safety profile of emactuzumab alone and in combination does not appear to preclude its use. No patients receiving emactuzumab monotherapy showed an objective response; the objective response rate for emactuzumab in combination with paclitaxel was 7% across all doses. Skin macrophages rather than peripheral blood monocytes or circulating colony-stimulating factor-1 were identified as an optimal surrogate PD marker to select the OBD. Emactuzumab treatment alone and in combination with paclitaxel resulted in a plateau of immunosuppressive TAM reduction at the OBD of 1000mg administered every 2weeks. Conclusions Emactuzumab showed specific reduction of immunosuppressive TAMs at the OBD in both treatment arms but did not result in clinically relevant antitumor activity alone or in combination with paclitaxel. (ClinicalTrials.gov Identifier: NCT01494688)

Entrectinib is a potent and selective tyrosine kinase inhibitor (TKI) of TRKA/B/C, ROS1, and ALK with both systemic and CNS activities, which has recently received FDA approval for ROS1 fusion-positive non-small cell lung cancer and NTRK fusion-positive solid tumors. This paper describes the application of a physiologically based biophamaceutics modeling (PBBM) during clinical development to understand the impact of food and gastric pH changes on absorption of this lipophilic, basic, molecule with reasonable permeability but strongly pH-dependent solubility. GastroPlus™ was used to develop a physiologically based pharmacokinetics (PBPK) model integrating in vitro and in silico data and dissolution studies and in silico modelling in DDDPlus™ were used to understand the role of self-buffering and acidulant on formulation performance. Models were verified by comparison of simulated pharmacokinetics for acidulant and non-acidulant containing formulations to clinical data from a food effect study and relative bioavailability studies with and without the gastric acid-reducing agent lansoprazole. A negligible food effect and minor pH-dependent drug-drug interaction for the market formulation were predicted based on biorelevant in vitro measurements, dissolution studies, and in silico modelling and were confirmed in clinical studies. These outcomes were explained as due to the acidulant counteracting entrectinib self-buffering and greatly reducing the effect of gastric pH changes. Finally, sensitivity analyses with the verified model were applied to support drug product quality. PBBM has great potential to streamline late-stage drug development and may have impact on regulatory questions.

Targeted biological therapies may achieve maximal therapeutic efficacy at doses below the maximum tolerated dose (MTD); therefore, the search for the MTD in clinical studies may not be ideal for these agents. Emactuzumab is an investigational monoclonal antibody that binds to and inhibits the activation of the cell surface colony-stimulating factor-1 receptor. Here, we show how modeling target-mediated drug disposition coupled with pharmacodynamic end points was used to optimize the dose of emactuzumab without defining an MTD. The model could be used to recommend doses across different disease indications. The approach recommended an optimal biological dose of emactuzumab for dosing every 2 weeks (q2w) ≥ 900 mg, approximately three-fold lower than the highest dose tested clinically. The model predicted that emactuzumab doses ≥ 900 mg q2w would achieve target saturation in excess of 90% over the entire dosing cycle. Subsequently, a dose of 1,000 mg q2w was used in the extension phase of a phase I study of emactuzumab in patients with advanced solid tumors or diffuse-type tenosynovial giant cell tumor. Clinical data from this study were consistent with model predictions. The model was also used to predict the optimum dose of emactuzumab for use with dosing every 3 weeks, enabling dosing flexibility with respect to comedications. In summary, this work demonstrates the value of quantitative clinical pharmacology approaches to dose selection in oncology as opposed to traditional MTD methods.

Combination of targeted therapies is expected to provide superior efficacy in the treatment of cancer either by enhanced antitumor activity or by preventing or delaying the development of resistance. Common challenges in developing combination therapies include the potential of additive and aggravated toxicities associated with pharmacologically related adverse effects. We have recently reported that combination of anti-HER2 and anti-HER3 antibodies, pertuzumab and lumretuzumab, along with paclitaxel chemotherapy in metastatic breast cancer, resulted in a high incidence of diarrhea that ultimately limited further clinical development of this combination. Here, we further dissected the diarrhea profile of the various patient dose cohorts and carried out in vitro investigations in human colon cell lines and explants to decipher the contribution and the mechanism of anti-HER2/3 therapeutic antibodies to intestinal epithelium malfunction. Our clinical investigations in patients revealed that while dose reduction of lumretuzumab, omission of pertuzumab loading dose, and introduction of a prophylactic antidiarrheal treatment reduced most severe adverse events, patients still suffered from persistent diarrhea during the treatment. Our in vitro investigations showed that pertuzumab and lumretuzumab combination treatment resulted in upregulation of chloride channel activity without indication of intestinal barrier disruption. Overall, our findings provide a mechanistic rationale to explore alternative of conventional antigut motility using medication targeting chloride channel activity to mitigate diarrhea of HER combination therapies. Mol Cancer Ther; 17(7); 1464–74. ©2018 AACR.

This study aimed at evaluating if pharmacokinetic and pharmacodynamic data from the first few patients treated with an investigational monoclonal antibody in a dose-escalation study can be used to guide the early initiation of potentially more efficacious combination regimens. Emerging pharmacokinetic and pharmacodynamic data from the first nine patients treated with lumretuzumab (a glycoengineered anti-HER3 monoclonal antibody) monotherapy at doses from 100 to 400 mg q2w were used along with a pharmacokinetic model that incorporated target-mediated drug disposition to guide the selection of the starting dose for use in combination regimens. The dose-escalation study investigated lumretuzumab doses up to 2000 mg q2w and a maximum tolerated dose was not reached. However, the model described in this report predicted linear lumretuzumab pharmacokinetics and >95% target saturation at doses ≥400 mg q2w. These data, along with safety data, contributed to the decision to begin dose-escalation studies in combination with cetuximab and erlotinib using a starting dose of 400 mg lumretuzumab. Pharmacokinetic data from patients treated with lumretuzumab 400–2000 mg q2w in combination regimens were consistent with the model predictions. PK/PD modelling of emerging clinical data might accelerate development programs by enabling additional parts of a trial to commence before completion of the monotherapy part. The dose and schedule of lumretuzumab were optimised for concomitant therapy at doses substantially below the highest dose investigated.

The phase 1/2 STARTRK-NG trial is evaluating entrectinib, a CNS-penetrant oral inhibitor of TRK, ROS1 and ALK tyrosine kinases, in children with solid tumors, including primary CNS tumors. Eligible patients are ≤22y with recurrent/refractory solid tumors. The recommended dose was determined in all-comers, and then expansion cohorts of CNS and solid tumors with NTRK1/2/3, ROS1 or ALK gene fusions, and neuroblastomas (NBL) regardless of mutation spectrum, were enrolled. Investigator-assessed response was classified as complete (CR) or partial response (PR), stable (SD) or progressive disease using RANO (CNS), RECIST (solid tumors), or Curie score (NBL). By the clinical data cut-off, 01 April 2019, 32 patients were enrolled. As of 31 Oct 2018 (enrollment data cut-off), 29 patients were enrolled and included in the evaluable population. Median age was 7y (range 4.9m to 20y). Entrectinib was well tolerated; phase 1 dose-limiting toxicities were: elevated creatinine, dysgeusia, fatigue, and pulmonary edema. The recommended dose was 550mg/m2 daily; all responses occurred at doses ≥400mg/m2. In 6 patients with high-grade CNS tumors, all gene-fusion-positive, ORR was 100% (Investigator-assessed responses): 2 CR (ETV6-NTRK3, EML1-NTRK2); 4 PR (TPR-NTRK1, KANK1-NTRK2, EEF1G-ROS1, GOPC-ROS1). In extracranial solid tumors 6/8 had a fusion; of these, 2 achieved a confirmed CR (DCTN1-ALK, ETV6-NTRK3), and 4 achieved PR (ETV6-NTRK3, EML4-NTRK3, TFG1-ROS1, KIF5B-ALK). Central imaging review is being performed and will be provided. Duration of therapy ranged from 0.2 to 22.2 months for all 32 patients. In responding patients, time to response ranged from 1 to 8.3 months. In children with refractory CNS tumors harboring NTRK1/2/3 or ROS1 fusions, entrectinib produced striking, rapid, and durable responses. No responses were seen in tumors lacking target gene fusions. These results support the continued evaluation of entrectinib in solid tumors with target gene fusions, especially high-grade CNS neoplasms.

Background: Inhibition of HER2 and HER3 heterodimerisation is a novel treatment concept in HER2-”low” expressing breast cancer (BC). Lumretuzumab, a glycoengineered monoclonal anti-HER3 antibody, in combination with pertuzumab has demonstrated synergistic anti-tumor activity in preclinical HER2–low expressing preclinical BC models. Methods: This open-label, multicenter phase I study selectively enrolled metastatic BC patients (pts) expressing HER3 protein and low levels of HER2 (defined as IHC 1+ and 2+ and ISH-negative) in a formalin-fixed paraffin-embedded pretreatment tumor biopsy sample. Eligible pts were treated with a combination of paclitaxel (PA) qw plus lumretuzumab (L) and pertuzumab (P) q3w in three dose cohorts. The safety, antitumor activity and tumor biomarkers including protein expression (IHC, MS) and mutational data (NGS) in association with clinical activity were evaluated. Results: Overall, 35 pts were included in this study. The median age was 60 (range: 33 to 77) years. The median number of prior treatments for metastatic disease ranged from 0 to 5 with 23 pts (65.7%) without prior chemotherapy for metastatic disease. Cohort 1 was treated with PA at 80 mg/m2, L at 1000 mg and P at 840 mg for Cycle 1 followed by 420 mg for the following cycles. This cohort was stopped after two pts both experienced grade 3 diarrhea within the first treatment cycle which was considered a dose-limiting toxicity (DLT). For Cohort 2 the dose of L was reduced to 500 mg based on PK modelling and simulation data. No DLTs were seen for the first 6 pts. A total of 20 pts were recruited with an objective response rate (ORR) and disease control rate (DCR) of 30% and 75%, respectively, and 56% and 78%, respectively, for 1st-line pts (n=9) in this cohort. Diarrhea (≥G3) and hypokalemia (≥G3) occurred in 50% and 55% of pts, respectively, and all pts experienced chronic diarrhea throughout the course of treatment. For Cohort 3 the dose of L was maintained at 500 mg, PA at 80 mg/m2, and P was administered at 420 mg at all cycles. In addition, a prophylactic loperamide regimen was introduced. Altogether, 13 pts - all 1st-line for metastatic disease - were treated. No DLTs were seen for the first 6 pts. Diarrhea (≥G3) and hypokalemia (≥G3) were reduced to 31% and 15%, respectively, but chronic diarrhea was still observed throughout the treatment in all pts. The ORR and DCR were 31% and 77%, respectively. Preliminary mechanistic safety experiments revealed HER2/HER3-dependent chloride channels in the intestine as likely cause of diarrhea. Biomarker data will be presented along with updated clinical and safety data. Conclusions: The combination of L, P and PA was associated with high rates of persistent diarrhea. Dose modifications and prophylactic anti-diarrheal medication led to significantly reduced diarrhea intensity but did not change the incidence and persistence of diarrhea overall. Despite encouraging clinical activity especially in 1st line pts, the therapeutic window of this combination is too low to warrant further clinical development. Citation Format: Schneeweiss A, Park-Simon T-W, Albanell J, Lassen U, Cortes J, Dieras V, May M, Schindler C, Marmé F, Cejalvo JM, Martinez-Garcia M, Gonzalez I, Lopez-Martin J, Welt A, Joly F, Michielin F, Jacob W, Adessi C, Moisan A, Meneses-Lorente G, James I, Ceppi M, Hasmann M, Weisser M, Cervantes A. Phase Ib study evaluating the safety and clinical activity of lumretuzumab combined with pertuzumab and paclitaxel in HER2-low metastatic breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-11-13.

Summary Background Diffuse-type tenosynovial giant cell tumour (dt-GCT) of the soft tissue (alternatively known as pigmented villonodular synovitis), an orphan disease with unmet medical need, is characterised by an overexpression of colony-stimulating factor 1 (CSF1), and is usually caused by a chromosomal translocation involving CSF1. CSF1 receptor (CSF1R) activation leads to the recruitment of CSF1R-expressing cells of the mononuclear phagocyte lineage that constitute the tumor mass in dt-GCT. Emactuzumab (RG7155) is a novel monoclonal antibody that inhibits CSF1R activation. We have assessed the safety, tolerability and activity of emactuzumab in patients with Dt-GCT of the soft tissue. Methods In this phase 1, first-in-human dose-escalation and dose-expansion study, eligible patients were aged 18 years or older with dt-GCT of the soft tissue with locally advanced disease or resectable tumours requiring extensive surgery, an Eastern Cooperative Oncology Group performance status of 1 or less, measurable disease according to Response Evaluation Criteria In Solid Tumors version 1.1, and adequate end-organ function. Patients with GCT of the bone were not eligible. Patients received intravenous emactuzumab at 900 mg, 1350 mg, or 2000 mg every 2 weeks in the dose-escalation phase and at the optimal biological dose in a dose-expansion phase. The primary objective was to evaluate the safety and tolerability of emactuzumab, and to determine the maximum tolerated dose or optimal biological dose. All treated patients were included in the analyses. Expansion cohorts are currently ongoing. This study is registered with ClinicalTrials.gov, number NCT01494688. Findings Between July 26, 2012, and Oct 21, 2013, 12 patients were enrolled in the dose-escalation phase. No dose-limiting toxicities were noted in the dose-escalation cohort; on the basis of pharmacokinetic, pharmacodynamic, and safety information, we chose a dose of 1000 mg every 2 week for the dose-expansion cohort, into which 17 patients were enrolled. Owing to different cutoff dates for safety and efficacy readouts, the safety population comprised 25 patients. Common adverse events after emactuzumab treatment were facial oedema (16 [64%] of 25 patients), asthenia (14 [56%]), and pruritus (14 [56%]). Five serious adverse events (periorbital oedema, lupus erythematosus [occurring twice], erythema, and dermohypodermitis all experienced by one [4%] patient each) were reported in five patients. Three of the five serious adverse events—periorbital oedema (one [4%]), lupus erythematosus (one [4%]), and dermohypodermitis (one [4%])—were assessed as grade 3. Two other grade 3 events were reported: mucositis (one [4%]) and fatigue (one [4%]). 24 (86%) of 28 patients achieved an objective response; two (7%) patients achieved a complete response. Interpretation Further study of dt-GCT is warranted and different possibilities, such as an international collaboration with cooperative groups to assure appropriate recruitment in this rare disease, are currently being assessed. Funding F Hoffmann-La Roche.

To inform lumretuzumab and pertuzumab dose modifications in order to decrease the incidence, severity, and duration of the diarrhea events in metastatic breast cancer patients treated with a combination therapy of lumretuzumab (anti-HER3) in combination with pertuzumab (anti-HER2) and paclitaxel using quantitative clinical pharmacology modeling approaches. The safety and pharmacokinetic (PK) data from three clinical trials (lumretuzumab monotherapy n = 47, pertuzumab monotherapy n = 78, and the combination therapy of lumretuzumab, pertuzumab and paclitaxel n = 35) were pooled together to develop a continuous-time discrete states Markov model describing the dynamics of the diarrhea events. The model was able to capture the time course of different severities of diarrhea reasonably well. The effect of lumretuzumab and pertuzumab was well described by an Emax function indicating an increased rate of transition from moderate to mild or more severe diarrhea with higher doses. The concentration needed to trigger or worsen diarrhea episodes was estimated to be 120-fold lower in combination therapy compared to monotherapy, suggesting strong synergy between the two monoclonal antibodies. The prophylactic effect of loperamide in a subset of patients was also well captured by the model with a clear tendency to reduce the occurrence of diarrhea events. This work shows that PK-toxicity modeling provides insight into how the severity of key adverse events evolves over time and highlights the potential use to support decision making in drug development.

Summary Purpose To investigate the safety and clinical activity of comprehensive human epidermal growth factor receptor (HER) family receptor inhibition using lumretuzumab (anti-HER3) and pertuzumab (anti-HER2) in combination with paclitaxel in patients with metastatic breast cancer (MBC). Methods This phase Ib study enrolled 35 MBC patients (first line or higher) with HER3-positive and HER2-low (immunohistochemistry 1+ to 2+ and in-situ hybridization negative) tumors. Patients received lumretuzumab (1000 mg in Cohort 1; 500 mg in Cohorts 2 and 3) plus pertuzumab (840 mg loading dose [LD] followed by 420 mg in Cohorts 1 and 2; 420 mg without LD in Cohort 3) every 3 weeks, plus paclitaxel (80 mg/m2 weekly in all cohorts). Patients in Cohort 3 received prophylactic loperamide treatment. Results Diarrhea grade 3 was a dose-limiting toxicity of Cohort 1 defining the maximum tolerated dose of lumretuzumab when given in combination with pertuzumab and paclitaxel at 500 mg every three weeks. Grade 3 diarrhea decreased from 50% (Cohort 2) to 30.8% (Cohort 3) with prophylactic loperamide administration and omission of the pertuzumab LD, nonetheless, all patients still experienced diarrhea. In first-line MBC patients, the objective response rate in Cohorts 2 and 3 was 55% and 38.5%, respectively. No relationship between HER2 and HER3 expression or somatic mutations and clinical response was observed. Conclusions Combination treatment with lumretuzumab, pertuzumab and paclitaxel was associated with a high incidence of diarrhea. Despite the efforts to alter dosing, the therapeutic window remained too narrow to warrant further clinical development. Trial registration: on ClinicalTrials.gov with the identifier NCT01918254 first registered on 3rd July 2013.

Purpose: This study investigated the safety, clinical activity, and target-associated biomarkers of lumretuzumab, a humanized, glycoengineered, anti-HER3 monoclonal antibody (mAb), in combination with the EGFR-blocking agents erlotinib or cetuximab in patients with advanced HER3-positive carcinomas.Experimental Design: The study included two parts: dose escalation and dose extension phases with lumretuzumab in combination with either cetuximab or erlotinib, respectively. In both parts, patients received lumretuzumab doses from 400 to 2,000 mg plus cetuximab or erlotinib according to standard posology, respectively. The effect of HRG mRNA and HER3 mRNA and protein expression were investigated in a dedicated extension cohort of squamous non–small cell lung cancer (sqNSCLC) patients treated with lumretuzumab and erlotinib.Results: Altogether, 120 patients were treated. One dose-limiting toxicity (DLT) in the cetuximab part and two DLTs in the erlotinib part were reported. The most frequent adverse events were gastrointestinal and skin toxicities, which were manageable. The objective response rate (ORR) was 6.1% in the cetuximab part and 4.2% in the erlotinib part. In the sqNSCLC extension cohort of the erlotinib part, higher tumor HRG and HER3 mRNA levels were associated with a numerically higher disease control rate but not ORR.Conclusions: The toxicity profile of lumretuzumab in combination with cetuximab and erlotinib was manageable, but only modest clinical activity was observed across tumor types. In the sqNSCLC cohort, there was no evidence of meaningful clinical benefit despite enriching for tumors with higher HRG mRNA expression levels. Clin Cancer Res; 23(18); 5406–15. ©2017 AACR.

10009 Background: Entrectinib is a CNS-penetrant oral inhibitor of TrkA/B/C, ROS1 and ALK tyrosine kinases. We report the efficacy of entrectinib in children with recurrent/refractory solid or CNS tumors. Methods: Patients ≤ 20y old with recurrent/refractory solid tumors were eligible. After determination of the recommended dose in all-comers, disease-specific expansion cohorts of CNS and solid tumors harboring target aberrations in NTRK1/2/3, ROS1 or ALK, and neuroblastoma (NBL), regardless of mutation spectrum, were enrolled. Response, assessed by Investigator, was classified as complete response (CR), partial response (PR), stable disease (SD) or progressive disease (PD) using RANO for CNS tumors, RECIST for solid tumors, and Curie score for NBL. Results: Between May 2016 and October 2018, 29 patients aged 4.9m–20y (median 7y) were enrolled and 28 were evaluated for response. Entrectinib was well tolerated. Dose limiting toxicities were elevated creatinine, dysgeusia, fatigue and pulmonary edema. The recommended dose was 550 mg/m2 daily. All responses occurred at doses ≥ 400 mg/m2. In CNS tumors (n = 6), all high-grade with gene fusions: 1 achieved a CR ( ETV6-NTRK3); 3 achieved a PR ( TPR-NTRK1, EEF1G-ROS1, EML1-NTRK2); 1 achieved an unconfirmed PR ( GOPC-ROS1); and 1 has yet to be evaluated ( KANK1-NTRK2). In extracranial solid tumors (n = 8), 6 had a fusion of whom 1 achieved a CR ( DCTN1-ALK) and 5 achieved a PR ( TFG1-ROS1, EML4-NTRK3, ETV6-NTRK3, KIF5B-ALK, ETV6-NTRK3). In NBL (n = 15): 1 achieved a CR ( ALK F1174L). Median duration of therapy was 85d (6–592d) for all patients; 56d (6–338d) for non-responders; and 281d (56–592d) for responders. Median time to response was 57d (30–58d). Conclusions: Entrectinib produced striking, rapid and durable responses in all children with refractory CNS and solid tumors harboring NTRK1/2/3, ROS1 or ALK fusions (11 out of 11) as well as in an ALK-mutated NBL. No responses were seen in tumors lacking aberrations in target kinases. These results support the continued evaluation of entrectinib as a targeted therapeutic in solid tumors with NTRK1/2/3, ROS1 and ALK fusions, especially in high-grade CNS neoplasms. Clinical trial information: NCT02650401.

Rationale: High-density lipoprotein cholesterol elevation via cholesteryl ester transfer protein (CETP) inhibition represents a novel therapy for atherosclerosis, which also may have relevance for type 2 diabetes mellitus. Objective: The current study assessed the effects of a CETP inhibitor on postprandial insulin, ex vivo insulin secretion, and cholesterol efflux from pancreatic β-cells. Methods and Results: Healthy participants received a daily dose of CETP inhibitor (n=10) or placebo (n=15) for 14 days in a randomized double-blind study. Insulin secretion and cholesterol efflux from MIN6N8 β-cells were determined after incubation with treated plasma. CETP inhibition increased plasma high-density lipoprotein cholesterol, apolipoprotein AI, and postprandial insulin. MIN6N8 β-cells incubated with plasma from CETP inhibitor–treated individuals (compared with placebo) exhibited an increase in both glucose-stimulated insulin secretion and cholesterol efflux over the 14-day treatment period. Conclusions: CETP inhibition increased postprandial insulin and promoted ex vivo β-cell glucose-stimulated insulin secretion, potentially via enhanced β-cell cholesterol efflux.

Dalcetrapib targets cholesteryl ester transfer protein and increases high-density lipoprotein cholesterol (HDL-C) levels. It is in clinical development for the prevention of cardiovascular events and will likely be used in combination with standard of care, including statins. Three crossover studies in healthy males investigated the pharmacokinetic drug-drug interaction potential of 900 mg dalcetrapib and statins: two 3-period studies (dalcetrapib plus pravastatin or rosuvastatin) and a 2-period study (dalcetrapib plus simvastatin). Effect on lipids and safety were secondary end points. The 900 mg dose investigated is higher than the 600 mg dose currently being investigated in Phase III. Coadministration of dalcetrapib with pravastatin, rosuvastatin, or simvastatin was not associated with significant increases in statin exposure except for a 26% increase in rosuvastatin C(max) (90% CI 1.088 to 1.468) but not AUC(0-24) (90% CI 0.931 to 1.085). Dalcetrapib AUC(0-24) and C(max) were not significantly altered by coadministration with pravastatin, and were significantly lower when dalcetrapib was coadministered with rosuvastatin or simvastatin compared with dalcetrapib alone. The HDL-C increase with dalcetrapib was not compromised by coadministration with statins, and reduction in low-density lipoprotein cholesterol with dalcetrapib coadministered with statins was greater than with statins alone. Dalcetrapib alone and coadministered with statins was generally well tolerated.

Dalcetrapib, which targets cholesteryl ester transfer protein, is in clinical development for prevention of cardiovascular events and is likely to be used concomitantly with statins. Two studies investigated co-administration of dalcetrapib with atorvastatin and any effects of the timing of atorvastatin on the pharmacokinetics of dalcetrapib.Two crossover studies were performed in healthy subjects: a two-period study of dalcetrapib 900 mg concurrently with atorvastatin (concurrent dosing study) and a three-period study of dalcetrapib 600 mg (dose chosen for Phase III) with atorvastatin concurrently or serially 4 h after dalcetrapib (interval dosing study).The primary pharmacokinetic end points were AUC(0 - 24) and C(max); lipid effects and tolerability were secondary end points.In the concurrent study (n = 26), co-administration reduced dalcetrapib AUC(0 - 24) and C(max) and caused small changes in AUC(0 - 24) and C(max) of atorvastatin and its active metabolites. In the interval study (n = 52), serial and concurrent co-administration of atorvastatin resulted in similar reductions in dalcetrapib exposure that were comparable to those observed in the concurrent dosing study. Co-administration did not decrease the efficacy of dalcetrapib or atorvastatin and was generally well tolerated.These results indicate no clinically relevant interactions for co-administration of dalcetrapib with atorvastatin.

Purpose: A first-in-human phase I study was conducted to characterize safety, efficacy, and pharmacokinetic (PK) and pharmacodynamic (PD) properties of lumretuzumab, a humanized and glycoengineered anti-HER3 monoclonal antibody, in patients with advanced cancer. Experimental Design: Twenty-five patients with histologically confirmed HER3-expressing tumors received lumretuzumab (100, 200, 400, 800, 1,600, and 2,000 mg) every two weeks (q2w) in 3+3 dose-escalation phase. In addition, 22 patients were enrolled into an extension cohort at 2,000 mg q2w. Results: There were no dose-limiting toxicities. Common adverse events (any grade) included diarrhea (22 patients, 46.8%), fatigue (21 patients, 44.7%), decreased appetite (15 patients, 31.9%), infusion-related reactions (13 patients, 27.7%), and constipation (10 patients, 21.3%). The peak concentration (Cmax) and area under the concentration–time curve up to the last measurable concentration (AUClast) of lumretuzumab increased more than dose proportionally from 100 mg up to 400 mg. Linear PK was observed with doses ≥400 mg q2w indicating target-mediated drug disposition saturation. Downregulation of HER3 membranous protein was observed in on-treatment tumor biopsies from 200 mg, and was maximal at and above 400 mg. An ex vivo assay demonstrated increased activation potential of peripheral NK lymphocytes with lumretuzumab compared with a non-glycoengineered anti-HER3 antibody. Ten patients (21.3%) had stable disease and remained on study at a median of 111 days (range, 80–225 days). Conclusions: Lumretuzumab was well tolerated and showed evidence of clinical activity. Linear serum PK properties and plateauing of PD effects in serial tumor biopsies indicate optimal biologically active doses of lumretuzumab from 400 mg onwards. Clin Cancer Res; 22(4); 877–85. ©2015 AACR.

Introduction of selected amine containing side chains into the 3-position of N',2-diphenylquinoline-4-carbohydrazide based NK3 antagonists abolishes unwanted hPXR activation. Introduction of a fluorine at the 8-position is necessary to minimize unwanted hI(Kr) affinity and a piperazine N-tert-butyl group is necessary for metabolic stability. The lead compound (8m) occupies receptors within the CNS following oral dosing (Occ(90) 7 mg/kg po; plasma Occ(90) 0.4 microM) and has good selectivity and excellent PK properties.

The aim of this study was to validate a low-density DNA microarray "Rat HepatoChip", which contains 59 genes from a range of potential toxic markers and drug metabolism-related genes. Liver mRNA was isolated from rats dosed with six different chemicals, dexamethasone, troleandomycin, miconazole, clotrimazole, and methylclofanapate, which are all known to induce different cytochrome P450 genes, and isoniazid, which does not cause histopathological changes. Replicate microarrays were used to measure the variability in the chips and in the process. The average variability in signal between different chips observed in triplicate experiments was 33% ranging from 21 to 39% depending on genes. We also demonstrated a strong correlation between the liver histopathology and the gene expression profiles indicating that the gene expression profile reflects histopathological changes. These results suggest that the Rat HepatoChip microarray may provide a fast and effective tool for assessing the toxicity profile of developmental drug candidates during the drug discovery process.

An abnormal immune response may play apathogenic role in ulcerative colitis (UC). Animalmodels suggest that T-cell regulation may be of centralimportance in the inflammatory process. Our aims werethe characterization of the phenotype andfunctional status of circulating T-cells in ulcerativecolitis patients and to determine if activation-inducedcell death in CD4+ and CD8+lymphocytes in patients differs from healthy controls.Forty-eight patients (24 women and 24 men) fulfillingthe histopathological, clinical, and immunologicalcriteria for UC were studied. T-cell phenotype andfunction were studied in blood lymphocytes from patientswith ulcerative colitis and healthy donors by flowcytometric analysis, as well as [3H]thymidineincorporation. There were no significant differences in the percentage of T-cell subpopulations(CD3, CD4, CD8) and NK cells in the different groups.The percentage of cells in growth phase S+G2Mat two and three days of phytohemagglutinin (PHA) stimulation was significantly decreased in UCpatients, but the percentage of CD4+ andCD8+ cells in UC patients that showedapoptosis was not significantly different than that inthe control group. Proliferative responses to IL-4 also suggested that a reducedresponsiveness to this cytokine may be involved in UC.In conclusion, the impaired proliferative response toPHA of T lymphocytes from UC patients is not associated with an in vitro increase in theapoptotic response in CD4+ or CD8+cells. A reduced IL-4 response may be involved in thispeculiar mitogenic response. These changes may be pathogenic or a favorable adaptivemechanism.

Background. We conducted a phase I study to estimate the maximum tolerated dose and describe the dose-limiting toxicities and pharmacokinetics of oral capecitabine rapidly disintegrating tablets given concurrently with radiation therapy to children with newly diagnosed brainstem or high-grade gliomas. Methods. Children 3–21 y with newly diagnosed intrinsic brainstem or high-grade gliomas were eligible for enrollment. The starting dose was 500 mg/m 2 , given twice daily, with subsequent cohorts enrolled at 650 mg/m 2 and 850 mg/m 2 using a 3 + 3 phase I design. Children received capecitabine at the assigned dose daily for 9 wks starting from the first day of radiation therapy (RT). Following a 2-wk break, patients received 3 courses of capecitabine 1250 mg/m 2 twice daily for 14 days followed by a 7-day rest. Pharmacokinetic sampling was performed in consenting patients. Six additional patients with intrinsic brainstem gliomas were enrolled at the maximum tolerated dose to further characterize the pharmacokinetic and toxicity profiles. Results. Twenty-four patients were enrolled. Twenty were fully assessable for toxicity. Dose-limiting toxicities were palmar plantar erythroderma (grades 2 and 3) and elevation of alanine aminotransferase (grades 2 and 3). Systemic exposure to capecitabine and metabolites was similar to or slightly lower than predicted based on adult data. Conclusions. Capecitabine with concurrent RT was generally well tolerated. The recommended phase II capecitabine dose when given with concurrent RT is 650 mg/m 2 , administered twice daily. A phase II study to evaluate the efficacy of this regimen in children with intrinsic brainstem gliomas is in progress (PBTC-030).

11555Background: Lumretuzumab is a humanized, glycoengineered, monoclonal antibody targeting human epidermal growth factor receptor 3 (HER3), in phase Ib clinical development in patients with HER3-...

Background Preclinical studies have reported that the relative bioavailability of dalcetrapib, a modulator of cholesteryl ester transfer protein (CETP) inhibitor activity, was ∼60% higher when administered in the fed state compared with the fasting state. Objective This article reports on 3 studies conducted to assess the effects of food intake, timing of administration with respect to meals, and meal size and content on the relative bioavailability of dalcetrapib in healthy male subjects. Methods Three Phase I studies were performed in healthy subjects: (1) a 2-period crossover study of a single dose of dalcetrapib 900 mg administered in the fed and fasting states (fed versus fasting study [1999]); (2) a 3-period crossover study of a single dose of dalcetrapib 600 mg administered after a light morning meal, a standard evening meal, and a light evening meal (meal timing/size study [2005]); and (3) a 4-period crossover study of a single dose of dalcetrapib 600 mg administered 30 minutes after a high-fat meal or a standard evening meal, and 30 minutes before or 3 hours after the latter (high-fat meal study [2007]). Blood samples for pharmacokinetic analyses (AUC 0–36 or AUC 0–∞ , C max ) were collected up to 36, 144, and 96 hours after study drug administration in the fed versus fasting, meal timing/size, and high-fat meal studies, respectively. CETP activity was measured using a radioisotopic method in the fed versus fasting study and a fluorometric method in the meal timing/size and high-fat meal studies. Tolerability was assessed using monitoring of adverse events, laboratory parameters, vital signs, and ECG. Results Six men were enrolled in the fed versus fasting study (mean age, 37 years; mean body mass index [BMI], 23.6 kg/m 2 ). Dalcetrapib exposure was increased by 64% (AUC 0–36 ) and 126% (C max ) after administration in the fed state. Eighteen men were enrolled in the analysis of the effects of meal timing and size on the properties of dalcetrapib (mean age, 30.5 years; mean BMI, 25.1 kg/m 2 ). When dalcetrapib was administered after a light morning or a light evening meal, comparable values were found for mean dalcetrapib AUC 0–∞ (7400 and 7860 ng·h/mL, respectively) and C max (589 and 552 ng/mL), whereas administration after a standard evening meal was associated with increased AUC 0–∞ (14.3%–14.7%) and C max (25.5%–35.3%). Forty-nine men were included in the analysis in the high-fat meal study (mean age, 32.3 years; mean BMI, 23.9 kg/m 2 ). Compared with administration after a standard evening meal, administration after a high-fat evening meal was associated with increased AUC 0–∞ (34.9%) and C max (43.7%). Between-treatment differences in exposure within each study also were reflected in apparent differences in CETP activity. All treatments were generally well tolerated. Conclusions Dalcetrapib exposure was increased in the fed state and, to a lesser extent, was dependent on the size and fat content of the meal. Exposure was independent of dosing time. Dalcetrapib was generally well tolerated.

Evaluate dalcetrapib's potential to prolong QT intervals in healthy subjects.This was a single-center, randomized, active and placebo-controlled, six-sequence, three-period cross-over study. Participants [18-65 years; body mass index (BMI) 18-30 kg/m(2)] were randomized to daily doses of dalcetrapib 600 mg (therapeutic) or 3,900 mg (supratherapeutic) or to dalcetrapib-matched placebo for 7 days. On Day 8, subjects received single-dose moxifloxacin 400 mg (active control) or placebo, following the placebo or dalcetrapib, respectively. Electrocardiographic parameters were recorded on Days -1, 1, 7, and 8. The primary endpoint was the difference to placebo of time-matched change from baseline in the study-specific corrected QT interval (QTcS) at seven time-points within 24 h after dalcetrapib 3,900 mg on Day 7. An upper 95% confidence interval (CI)10 ms confirmed the absence of a significant effect. Pharmacokinetic and lipid-related parameters were measured.Subjects (n = 49) were predominantly male (71%), and all were white, with a mean age of 45 years and mean BMI of 25 kg/m(2). For the primary analysis, the upper 95% CI for dalcetrapib 3,900 mg was10 ms at all time-points. Similar findings were obtained for dalcetrapib 600 mg. Following the administration of moxifloxacin, the QTcS increased by5 ms. At Day 7, exposure for dalcetrapib 3,900 mg was approximately eightfold higher than that for dalcetrapib 600 mg [mean area under the plasma concentration-time curve between time 0 and 24 h 68,500 vs. 8,280 ng*h/mL; mean peak concentration 6,810 vs. 861 ng/mL]. Cholesteryl ester transfer protein activity was inhibited by 30%, and high-density lipoprotein cholesterol increased by 26% for dalcetrapib 600 mg. Dalcetrapib was well tolerated.Dalcetrapib is not associated with QT interval prolongation, even at doses markedly greater than intended therapeutically.

Cytochrome P450 (P450) induction may have considerable implications for drug therapy. Therefore, understanding the induction potential of a new chemical entity at an early stage in discovery is crucial to reduce the risk of failure in the clinic and help the identification of noninducing chemical structures. Availability of human viable tissue often limits evaluation of induction potential in human hepatocytes. A solution is to increase the time period during which the hepatocytes remain viable. In this study we have investigated the induction of several P450 isozymes in long-term cultured hepatocytes compared with short-term cultured hepatocytes from the same individuals. Short- and long-term cultured primary hepatocytes isolated from each individual were cultured in a 96-well format and treated for 24 h with a range of prototypical P450 inducers and Merck Research Laboratories compounds. CYP3A4, 1A1, 1A2, 2B6, and 2C9 mRNA levels were measured using quantitative real-time reverse transcriptase-polymerase chain reaction (TaqMan) from the same cultured hepatocyte wells. CYP3A4, 1A1, 1A2, 2B6, and 2C9 were shown to be inducible in long-term cultured hepatocytes. The -fold induction varied between donors, and between short- and long-term cultured hepatocytes from the same donor. However, this variability can be controlled by normalizing data from each hepatocyte preparation to a positive control. The use of long-term cultured hepatocytes on 96-well plates has proven to be sensitive, robust, and convenient for assessing P450 induction potential of new compound entities during the drug discovery process.

A new class of potent NK3R antagonists based on the N',2-diphenylquinoline-4-carbohydrazide core is described. In an ex vivo assay in gerbil, the lead compound 2g occupies receptors within the CNS following oral dosing (Occ(90) 30 mg/kg po; plasma Occ(90) 0.95 microM) and has good selectivity and promising PK properties.

Idiosyncratic adverse drug reactions (ADRs) are one of the most common causes of pharmaceutical withdrawals and labeling changes. Most ADRs are caused by drugs that form reactive species that can bind covalently to macromolecules such as proteins. The current methodology for the measurement of covalent binding relies on the use of radiolabeled material that requires an investment in time and resources not typically expended until later in the discovery process. Efforts are also made to identify reactive intermediates by the use of chemical trapping agents, such as reduced glutathione and cyanide, to form stable adducts that are characterized by liquid chromatography-tandem mass spectrometry and/or nuclear magnetic resonance spectroscopy. Here, we describe a high-throughput assay for the measurement of reactive intermediate formation. The method involves incubation of cold compound with liver microsomes in the presence of [14C]potassium cyanide. Hard electrophilic species would react with the trapping agent, resulting in the formation of a radiolabeled conjugate. Unreacted trapping agent is removed using solid-phase extraction, and the amount of radiolabeled conjugate present is determined by liquid scintillation counting. This newly developed screen has proved to be specific, sensitive, robust, and a powerful tool for assessing bioactivation potential.

A significant problem faced by pharmaceutical companies today is the failure of lead compounds in the later stages of development due to unexpected toxicities. We have used two-dimensional differential in-gel electrophoresis and mass spectrometry to identify a proteomic signature associated with hepatocellular steatosis in rats after dosing with a compound in preclinical development. Liver toxicity was monitored over a 5 day dosing regime using blood biochemical parameter measurements and histopathological analysis. As early as 6 h postdosing, livers showed hepatocellular vacuolation, which increased in extent and severity over the course of the study. Alterations in plasma glucose, alanine aminotransferase, and aspartate aminotransferase were not detected until the third day of dosing and changed in magnitude up to the final day. The proteomic changes were observed at the earliest time point, and many of these could be associated with known toxicological mechanisms involved in liver steatosis. This included up-regulation of pyruvate dehydrogenase, phenylalanine hydroxylase, and 2-oxoisovalerate dehydrogenase, which are involved in acetyl-CoA production, and down-regulation of sulfite oxidase, which could play a role in triglyceride accumulation. In addition, down-regulation of the chaperone-like protein, glucose-regulated protein 78, was consistent with the decreased expression of the secretory proteins serum paraoxonase, serum albumin, and peroxiredoxin IV. The correlation of these protein changes with the clinical and histological data and their occurrence before the onset of the biochemical changes suggest that they could serve as predictive biomarkers of compounds with a propensity to induce liver steatosis.

This paper describes the use of fluorescence two-dimensional differential in-gel electrophoresis in a multiplex analysis of two distinct proteomes. As a model system, cerebral cortex tissues were analyzed from neurokinin1 receptor knockout (NK(1)R-/-) and wild type (NK(1)R+/+) mice in an attempt to identify molecular pathways involved in the function of this protein. Paired NK(1)R-/- and NK(1)R+/+ samples were labeled with fluorescent Cy3 and Cy5 dyes and electrophoresed on the same two-dimensional gels. Scanning the gels at wavelengths specific for each dye revealed the two different proteomes which were overlaid and the differences in abundance of specific protein spots were determined by the Amersham Biosciences DeCyder Differential In-gel Analysis software. A Cy2-labeled sample pool was co-electrophoresed with all Cy3- and Cy5-labeled sample pairs as an internal standard providing a link for inter-gel comparisons and for more robust statistical analysis of the data. Eight spots were found to be upregulated and two downregulated in the NK(1)R-/- mice compared to NK(1)R+/+ controls. Matrix assisted laser desorption/ionisation-time of flight (MALDI-TOF) mass fingerprinting was used to identify the proteins. The results illustrate the power of this multiplex proteomics technology and illustrate how proteomics can be used to understand gene function.

The tumor microenvironment (TME) is a dynamic, highly complex network consisting of a variety of stromal cell types which support tumorigenesis. Myeloid derived cells probably represent the most abundant cell lineage in the TME, including tumor associated macrophages (TAMs). TAMs have been identified as an independent poor prognostic factor in several cancer types. RG7155 is a novel humanized monoclonal antibody targeting colony stimulating factor-1 receptor (CSF-1R). In vitro, RG7155 treatment results in cell death of CSF1-differentiated CD163+ M2-like macrophages. The associated mode of action and clinical proof of principle was evaluated in a first-in-man phase 1 study in patients with pigmented villonodular synovitis (PVNS), a neoplastic disorder characterized by CSF1 overexpression, as well as in patients with other advanced solid tumor entities. The associated biomarker program involves mandatory paired pre- and on-treatment biopsies of tumor and surrogate skin tissue as well as pharmacodynamic marker assessment in circulating blood. Biomarker analysis in tumor and skin includes multiplex IHC assays to assess tumor associated macrophages (CD163/CD68/CSF1R), T cells (CD4/CD8), tumor proliferation (Ki67) and vascularization (CD31). Tissue analysis is complemented by systematic peripheral blood sampling allowing flow cytometric analysis of circulating white blood cells (CD45/CD3/CD4/CD8/CD19/CD56/CD14/CD16/MHCII) and profiling of cytokines and growth factors. Here, we report the initial biomarker data from representative patients from the ongoing Phase 1 study. RG7155 induced a profound reduction of TAMs both in PVNS and various solid malignancies of up to 95% vs. baseline. We also observed depletion of macrophages in the skin which therefore may qualify as a surrogate tissue for mechanistic response. In peripheral blood RG7155 induced sustained modulation of CSF-1 (increase) and alternatively activated monocytes (decrease) was detected. Furthermore, preliminary data indicates a trend for overall increase of CD8/CD4 T cell ratio in the TME following RG7155 treatment, thus a secondary effect of TAM depletion causing intratumoral T cell modulation and tumor microenvironment re-education. Taken together, the individual biomarker program accompanying the first-in-man phase 1 study of RG7155 is demonstrating proof of mechanism and identified surrogate tissue as well as circulating markers to support optimal biological dose and regimen selection for future studies. Citation Format: Ann-Marie Bröske, Irina Klaman, Jayantha Ratnayake, Georgina Meneses-Lorente, Kevin Smart, Phiippe Cassier, Carlos Gomez-Roca, Christophe Le Tourneau, Antoine Italiano, Jean-Pierre Delord, Jean-Yves Blay, Carola Ries, Dominik Ruettinger, Michael Cannarile. Comprehensive biomarker program demonstrates proof of mechanism and modulation of the tumor microenvironment due to RG7155, a novel therapeutic antibody targeting tumor associated macrophages. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2940. doi:10.1158/1538-7445.AM2014-2940

Aim: To evaluate the safety profile of RG7116 in combination with cetuximab or erlotinib. Methods: Patients (pts) with advanced or metastatic carcinomas with centrally confirmed HER3 protein expression were included. RG7116 plus cetuximab (400 mg/m2 followed by 250 mg/m2 qw IV) and RG7116 plus erlotinib (150 mg/day p.o.) combinations were evaluated in a dose escalation study with “3 + 3” design at a starting dose of 400 mg IV of RG7116 in a q2w regimen. Results: Twenty-seven pts were enrolled in 5 cohorts (400 to 2000 mg) in the cetuximab arm. One dose-limiting toxicity (DLT) of grade 3 dehydration was reported in the 800-mg cohort. Twenty-seven pts were enrolled in 4 cohorts (400 to 2000 mg) in the erlotinib arm. One DLT was reported in the 1600-mg cohort (grade 3 diarrhea and grade 3 hypokalemia) and one DLT was reported in the 2000-mg cohort (grade 3 blood bilirubin increase). No maximum tolerated dose was reached. The most frequently reported adverse events of any grade were diarrhea (78%) and rash (59%) for the cetuximab arm and diarrhea (82%) and decreased appetite (48%) for the erlotinib arm. In the erlotinib arm treatment-related grade 3 diarrhea was observed more frequently at higher doses of RG7116 (400 mg: 0%; 800 mg: 17%; 1600 mg: 43%; 2000 mg: 33%). Overall, infusion-related reactions related to RG7116 occurred in 11% of pts. Two of these were grade 3 (4%). The pharmacokinetic profile of RG7116 in combination with cetuximab and erlotinib was comparable to that in the monotherapy setting (Meulendijks et al. J Clin Oncol 31, 2013 suppl; abstr 2522). HER3 membranous protein down-regulation was observed from 400 mg onwards in on-treatment tumor and skin tissue. In the cetuximab arm, two pts with colorectal carcinoma had a confirmed partial response (PR). In the erlotinib arm, one patient with ovarian carcinoma had a confirmed PR. Metabolic PR on FDG-PET occurred in 42% of pts in the cetuximab arm and in 28% of pts in the erlotinib arm. Conclusions: RG7116 combination with cetuximab or erlotinib was well tolerated, and demonstrated preliminary signs of clinical activity. Disclosure: U.N. Lassen: discloses Research grants from Roche; A. Cervantes Ruiperez: discloses Research grants, advisory boards and lectures for Roche; C. Adessi, A. Keelara, F. Michielin, B. Bossenmaier, G. Meneses-Lorente, I. James, W. Jacob and M. Weisser: Employee of Roche. All other authors have declared no conflicts of interest.

11095 Background: Human epidermal growth factor receptor 3 (HER3) can play a critical role in tumor growth, proliferation and progression. The glycoengineered humanized monoclonal HER3-targeting an...