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Supplementary Figure S1: Left: CEA expression by immuno-histochemistry in the LS174T tumor mouse model: homogeneous cytoplasmic antigen distribution. Right: CEA expression in one of the treated patients (colorectal cancer): heterogeneous cytoplasmic antigen distribution with polarized apical accumulation.

Purpose: Optimal dosing is critical for immunocytokine-based cancer immunotherapy to maximize efficacy and minimize toxicity. Cergutuzumab amunaleukin (CEA-IL2v) is a novel CEA-targeted immunocytokine. We set out to develop a mathematical model to predict intratumoral CEA-IL2v concentrations following various systemic dosing intensities.Experimental Design: Sequential measurements of CEA-IL2v plasma concentrations in 74 patients with solid tumors were applied in a series of differential equations to devise a model that also incorporates the peripheral concentrations of IL2 receptor–positive cell populations (i.e., CD8+, CD4+, NK, and B cells), which affect tumor bioavailability of CEA-IL2v. Imaging data from a subset of 14 patients were subsequently utilized to additionally predict antibody uptake in tumor tissues.Results: We created a pharmacokinetic/pharmacodynamic mathematical model that incorporates the expansion of IL2R-positive target cells at multiple dose levels and different schedules of CEA-IL2v. Model-based prediction of drug levels correlated with the concentration of IL2R-positive cells in the peripheral blood of patients. The pharmacokinetic model was further refined and extended by adding a model of antibody uptake, which is based on drug dose and the biological properties of the tumor. In silico predictions of our model correlated with imaging data and demonstrated that a dose-dense schedule comprising escalating doses and shortened intervals of drug administration can improve intratumoral drug uptake and overcome consumption of CEA-IL2v by the expanding population of IL2R-positive cells.Conclusions: The model presented here allows simulation of individualized treatment plans for optimal dosing and scheduling of immunocytokines for anticancer immunotherapy. Clin Cancer Res; 24(14); 3325–33. ©2018 AACR.See related commentary by Ruiz-Cerdá et al., p. 3236

Supplemental Table S2: Model parameter estimates. For model equations, refer to supplemental material.

Hepatic cirrhosis is an increasing cause of mortality in developed countries-it is the pathological sequela of chronic liver diseases, and the final liver fibrosis stage. Since cirrhosis evolves from the asymptomatic phase, it is of paramount importance to detect it as quickly as possible, because entering the symptomatic phase commonly leads to hospitalization and can be fatal. Understanding the state of the liver based on the abdominal computed tomography (CT) scans is tedious, user-dependent and lacks reproducibility. We tackle these issues and propose an end-to-end and reproducible approach for detecting cirrhosis from CT. It benefits from the introduced clinically-inspired features that reflect the patient's characteristics which are often investigated by experienced radiologists during the screening process. Such features are coupled with the radiomic ones extracted from the liver, and from the suggested region of interest which captures the liver's boundary. The rigorous experiments, performed over two heterogeneous clinical datasets (two cohorts of 241 and 32 patients) revealed that extracting radiomic features from the liver's rectified contour is pivotal to enhance the classification abilities of the supervised learners. Also, capturing clinically-inspired image features significantly improved the performance of such models, and the proposed features were consistently selected as the important ones. Finally, we showed that selecting the most discriminative features leads to the Pareto-optimal models with enhanced feature-level interpretability, as the number of features was dramatically reduced (280×) from thousands to tens.

CD8-expressing T cells are the main effector cells in cancer immunotherapy. Treatment-induced changes in intratumoral CD8+ T cells may represent a biomarker to identify patients responding to cancer immunotherapy. Here, we have used a 89Zr-radiolabeled human CD8-specific minibody (89Zr-Df-IAB22M2C) to monitor CD8+ T-cell tumor infiltrates by PET. The ability of this tracer to quantify CD8+ T-cell tumor infiltrates was evaluated in preclinical studies following single-agent treatment with FOLR1-T-cell bispecific (TCB) antibody and combination therapy of CEA-TCB (RG7802) and CEA-targeted 4-1BB agonist CEA-4-1BBL. In vitro cytotoxicity assays with peripheral blood mononuclear cells and CEA-expressing MKN-45 gastric or FOLR1-expressing HeLa cervical cancer cells confirmed noninterference of the anti-CD8-PET-tracer with the mode of action of CEA-TCB/CEA-4-1BBL and FOLR1-TCB at relevant doses. In vivo, the extent of tumor regression induced by combination treatment with CEA-TCB/CEA-4-1BBL in MKN-45 tumor–bearing humanized mice correlated with intratumoral CD8+ T-cell infiltration. This was detectable by 89Zr-IAB22M2C-PET and γ-counting. Similarly, single-agent treatment with FOLR1-TCB induced strong CD8+ T-cell infiltration in HeLa tumors, where 89Zr-Df-IAB22M2C again was able to detect CD8 tumor infiltrates. CD8-IHC confirmed the PET imaging results. Taken together, the anti-CD8-minibody 89Zr-Df-IAB22M2C revealed a high sensitivity for the detection of intratumoral CD8+ T-cell infiltrates upon either single or combination treatment with TCB antibody–based fusion proteins. These results provide further evidence that the anti-CD8 tracer, which is currently in clinical phase II, is a promising monitoring tool for intratumoral CD8+ T cells in patients treated with cancer immunotherapy. Significance: Monitoring the pharmacodynamic activity of cancer immunotherapy with novel molecular imaging tools such as 89Zr-Df-IAB22M2C for PET imaging is of prime importance to identify patients responding early to cancer immunotherapy.

Purpose: Optimal dosing is critical for immunocytokine-based cancer immunotherapy to maximize efficacy and minimize toxicity. Cergutuzumab amunaleukin (CEA-IL2v) is a novel CEA-targeted immunocytokine. We set out to develop a mathematical model to predict intratumoral CEA-IL2v concentrations following various systemic dosing intensities. Experimental Design: Sequential measurements of CEA-IL2v plasma concentrations in 74 patients with solid tumors were applied in a series of differential equations to devise a model that also incorporates the peripheral concentrations of IL2 receptor–positive cell populations (i.e., CD8+, CD4+, NK, and B cells), which affect tumor bioavailability of CEA-IL2v. Imaging data from a subset of 14 patients were subsequently utilized to additionally predict antibody uptake in tumor tissues. Results: We created a pharmacokinetic/pharmacodynamic mathematical model that incorporates the expansion of IL2R-positive target cells at multiple dose levels and different schedules of CEA-IL2v. Model-based prediction of drug levels correlated with the concentration of IL2R-positive cells in the peripheral blood of patients. The pharmacokinetic model was further refined and extended by adding a model of antibody uptake, which is based on drug dose and the biological properties of the tumor. In silico predictions of our model correlated with imaging data and demonstrated that a dose-dense schedule comprising escalating doses and shortened intervals of drug administration can improve intratumoral drug uptake and overcome consumption of CEA-IL2v by the expanding population of IL2R-positive cells. Conclusions: The model presented here allows simulation of individualized treatment plans for optimal dosing and scheduling of immunocytokines for anticancer immunotherapy. Clin Cancer Res; 24(14); 3325–33. ©2018 AACR. See related commentary by Ruiz-Cerdá et al., p. 3236

RO5323441 is a humanized anti-placental growth factor (PlGF) monoclonal antibody that has shown preclinical activity in several cancer models. The objective of this analysis is to examine the pharmacokinetic (PK) results from four Phase I studies that have been conducted with RO5323441 (n = 61) and to report an apparent drug–drug interaction observed when RO5323441 was administered in combination with bevacizumab. The four Phase I studies were a multiple-ascending dose study in 23 patients with solid tumors (Study 1), an open-label study in seven patients with colorectal/ovarian cancer (Study 2), a sorafenib combination study in nine patients with hepatocellular carcinoma (Study 3), and a bevacizumab combination study in 22 patients with recurrent glioblastoma (Study 4). A two-compartment linear population PK model was developed from these four studies to characterize the PK of RO5323441 in patients with cancer. The PK properties of RO5323441 were similar in the first three studies. However, substantially higher RO5323441 exposures were observed in Study 4 when RO5323441 was administered in combination with bevacizumab. A linear two-compartmental population PK model indicated that the co-administration of bevacizumab would decrease the clearance of RO5323441 by 53%. Clinical data suggested that the decrease in RO5323441 clearance was inversely associated with bevacizumab exposure. The exact reason for the increase in RO5323441 exposure following bevacizumab co-administration is not currently known. One possibility is a drug–drug interaction via a target-trapping mechanism that is mediated by the vascular endothelial growth factor receptor-1 (VEGFR-1).

Placental growth factor (PlGF) is a member of the proangiogenic vascular endothelial growth factor family, which is upregulated in many tumors. RO5323441, a humanized monoclonal antibody against PlGF, showed antitumor activity in human tumor xenografts. We therefore aimed to radiolabel RO5323441 and preclinically validate this tracer to study drug tumor uptake and organ distribution by PET imaging. Zr-89-RO5323441 was tested for stability and immunoreactivity in vitro. Methods: The tumor uptake and organ distribution for 10, 50, and 500 mu g of Zr-89-RO5323441 was assessed in mice bearing human PlGF-expressing hepatocellular cancer (Huh7) xenografts or human renal cell carcinoma (ACHN) xenografts without detectable human PlGF expression. The effect of pretreatment with RO5323441 (20 mg/kg) on Zr-89-RO5323441 tumor uptake was analyzed in Huh7 xenografts. In-111-IgG served as a control for nonspecific tumor uptake and organ distribution. Cy5-RO5323441 was injected to study the intratumor distribution of RO5323441 with fluorescence microscopy. Results: Zr-89-RO5323441 showed a time-and dose-dependent tumor accumulation. Uptake in Huh7 xenografts at 10 mu g of Zr-89-RO5323441 was 8.2% +/- 1.7% injected dose (ID)/cm(3) at 144 h after injection, and in ACHN xenografts it was 5.5 +/- 0.3 % ID/cm(3) (P = 0.03). RO5323441 pretreatment of Huh7 xenograft-bearing mice reduced Zr-89-RO5323441 tumor uptake to the level of nonspecific In-111-IgG uptake. Cy5-RO5323441 was present in the tumors mainly in the microenvironment. Conclusion: The findings show that RO5323441 tumor uptake is PlGF-specific and time-and dose-dependent.

ObjectivesExtra-thoracic tumors send out pilot cells that attach to the pulmonary endothelium. We hypothesized that this could alter regional lung mechanics (tissue stiffening or accumulation of fluid and inflammatory cells) through interactions with host cells. We explored this with serial inspiratory computed tomography (CT) and image matching to assess regional changes in lung expansion.Materials and methodsWe retrospectively assessed 44 pairs of two serial CT scans on 21 sarcoma patients: 12 without lung metastases and 9 with lung metastases. For each subject, two or more serial inspiratory clinically-derived CT scans were retrospectively collected. Two research-derived control groups were included: 7 normal nonsmokers and 12 asymptomatic smokers with two inspiratory scans taken the same day or one year apart respectively. We performed image registration for local-to-local matching scans to baseline, and derived local expansion and density changes at an acinar scale. Welch two sample t test was used for comparison between groups. Statistical significance was determined with a p value < 0.05.ResultsLung regions of metastatic sarcoma patients (but not the normal control group) demonstrated an increased proportion of normalized lung expansion between the first and second CT. These hyper-expanded regions were associated with, but not limited to, visible metastatic lung lesions. Compared with the normal control group, the percent of increased normalized hyper-expanded lung in sarcoma subjects was significantly increased (p < 0.05). There was also evidence of increased lung "tissue" volume (non-air components) in the hyper-expanded regions of the cancer subjects relative to non-hyper-expanded regions. "Tissue" volume increase was present in the hyper-expanded regions of metastatic and non-metastatic sarcoma subjects. This putatively could represent regional inflammation related to the presence of tumor pilot cell-host related interactions.ConclusionsThis new quantitative CT (QCT) method for linking serial acquired inspiratory CT images may provide a diagnostic and prognostic means to objectively characterize regional responses in the lung following oncological treatment and monitoring for lung metastases.

Background: To assess antivascular effects, and evaluate clinically translatable magnetic resonance imaging (MRI) biomarkers of tumour response in vivo, following treatment with vanucizumab, a bispecific human antibody against angiopoietin-2 (Ang-2) and vascular endothelial growth factor-A (VEGF-A). Methods: Colo205 colon cancer xenografts were imaged before and 5 days after treatment with a single 10 mg kg−1 dose of either vanucizumab, bevacizumab (anti-human VEGF-A), LC06 (anti-murine/human Ang-2) or omalizumab (anti-human IgE control). Volumetric response was assessed using T2-weighted MRI, and diffusion-weighted, dynamic contrast-enhanced (DCE) and susceptibility contrast MRI used to quantify tumour water diffusivity (apparent diffusion coefficient (ADC), × 106 mm2 s−1), vascular perfusion/permeability (Ktrans, min−1) and fractional blood volume (fBV, %) respectively. Pathological correlates were sought, and preliminary gene expression profiling performed. Results: Treatment with vanucizumab, bevacizumab or LC06 induced a significant (P

UNLABELLED: Two mitogen-activated protein kinase kinase (MAPK2, also known as MEK) inhibitors were assessed with (18)F-FDG PET in separate phase I clinical studies, clearly illustrating the potential of metabolic imaging for dose, dosing regimen, and compound selection in early-phase trials and utility for predicting nonresponding patients. METHODS: (18)F-FDG PET data were collected during 2 independent, phase I, dose-escalation trials of 2 novel MEK inhibitors (RO5126766 and RO4987655). PET acquisition procedures were standardized between the 2 trials, and PET images were analyzed centrally. Imaging was performed at baseline; at cycle 1, day 15; and at cycle 3, day 1. A 10-mm-diameter region of interest was defined for up to 5 lesions, and peak standardized uptake values were determined for each lesion. The relationship between PET response and pharmacokinetic factors (dose and exposure), inhibition of extracellular-signal-regulated kinase (ERK) phosphorylation in peripheral blood mononuclear cells, and anatomic tumor response as measured by Response Evaluation Criteria in Solid Tumors was investigated for both compounds. RESULTS: Seventy-six patients underwent PET, and 205 individual PET scans were analyzed. Strong evidence of biologic activity was seen as early as cycle 1, day 15, for both compounds. (18)F-FDG PET revealed striking differences between the 2 MEK inhibitors at their recommended dose for phase II investigation. The mean amplitude of the decrease in (18)F-FDG from baseline to cycle 1, day 15, was greater for patients receiving RO4987655 than for those receiving RO5126766 (47% vs. 16%, respectively; P = 0.052). Furthermore, a more pronounced relationship was seen between the change in (18)F-FDG uptake and dose or exposure and phosphorylated ERK inhibition in peripheral blood mononuclear cells in patients receiving RO4987655. For both investigational drugs, PET responses tended to be greatest in patients with melanoma tumors. (18)F-FDG was able to identify early nonresponding patients with a 97% negative predictive value. CONCLUSION: These data exemplify the role of (18)F-FDG PET for guiding the selection of novel investigational drugs, choosing dose in early-phase clinical development, and predicting nonresponding patients early in treatment.

Purpose: This phase I study assessed the maximum tolerated dose (MTD), dose-limiting toxicities (DLT), safety, pharmacokinetics, pharmacodynamics, and clinical activity of the first-in-class dual MEK/RAF inhibitor, RO5126766. Experimental Design: Initial dose-escalation was conducted using once daily dosing over 28 consecutive days in 4-week cycles. Further escalation was completed using 2 intermittent dosing schedules [7 days on treatment followed by 7 days off (7on/7off); 4 days on treatment followed by 3 days off (4on/3off)]. Results: Fifty-two patients received RO5126766 at doses of 0.1 to 2.7 mg once daily, 2.7 to 4.0 mg (4 on/3 off), or 2.7 to 5.0 mg (7 on/7 off). The most common DLTs were elevated creatine phosphokinase (CPK) and blurred vision. The MTD for each dosing schedule was 2.25 mg once daily, 4.0 mg (4 on/3 off), and 2.7 mg (7 on/7 off). The dose/schedule recommended for phase II (RP2D) investigation was 2.7 mg (4 on/3 off). Frequent adverse events included rash-related disorders (94.2%), elevated CPK (55.8%), and diarrhea (51.9%). Cmax occurred 1 to 2 hours after dosing and mean terminal half-life was approximately 60 hours. Pharmacodynamic changes included reduced ERK phosphorylation, an increase in apoptosis in tumor tissue, and a reduction in fluorodeoxyglucose (FDG) uptake after 15 days of dosing. Three partial responses were seen: two in BRAF-mutant melanoma tumors and one in an NRAS-mutant melanoma. Conclusion: This first-in-human study shows that oral RO5126766 has manageable toxicity, a favorable pharmacokinetic/pharmacodynamic profile, and encouraging preliminary antitumor activity in this population of heavily pretreated patients, achieving tumor shrinkage in around 40% of patients across all dose levels and all tumor types. Clin Cancer Res; 18(17); 4806–19. ©2012 AACR.

Many solid or semi-solid tissues have ultra-short or short T2* components that make them virtually “invisible” to standard MRI techniques. For this reason, methods such as ultra-short echo time (UTE) techniques were developed to investigate and detect some of these short and ultra-short time components. Here we report on the development and implementation of a novel version of the Single Point Ramped Imaging with T1 Enhancement (SPRITE) technique in order to image mouse models. The method, called diagonal-SPRITE, was optimized within hardware limitations such as duty cycle and gradient strength at high field. Preliminary in vivo MR T2* value of organs of normal mouse models and related T2* maps were generated. In addition, the sequence was applied to highlight stomach short T2* after the application of a long T2* suppression pulse and to achieve a positive contrast in a SPIO-labelled cells experiment.

Introduction: FAP-DR5 (RO6874813) is a novel bispecific antibody that binds with high and low affinity to fibroblast activation protein (FAP) and death receptor 5 (DR5), respectively. FAP-driven binding of RO6874813 mediates the high levels of DR5 clustering that are required for triggering cell death. Here, we present ongoing phase 1 data in patients with advanced solid tumors who were treated with escalating doses of single agent RO6874813 and assessed for tolerability. Methods: Study endpoints are safety and tolerability (primary) and antitumor activity (secondary). The study uses a continuous reassessment method (CRM) design for dose escalation. Patients received drug (IV ≤ 90 min) weekly (QW) or every other week (Q2W), starting with a run-in dose on Cycle 0/Day 1 (C0/D1) of 0.5 mg/kg for all cohorts to characterize linear and nonlinear pharmacokinetics (PK) . Doses administered at C1/D1 ranged from 1.0 to 45 mg/kg (3 or more patients per cohort). Dosing continued until progression of disease (PD) or toxicity occurred. Plasma biomarkers (BM) of DR5 binding (TRAIL, the DR5 ligand) and apoptosis (ccCK18) were measured at multiple timepoints. Archival or fresh tumor samples collected prior to RO6874813 treatment were analyzed for target expression by IHC and mRNA (qRT-PCR), cellular infiltrates, and apoptosis. Results: As of 26 April 2017, 32 patients have been treated with RO6874813. Patients had a median of 3.5 prior regimens (range 1-11) and received a median of 4 (range 2-21) doses of RO6874813. One patient (NSCLC) remains on treatment; 31 discontinued treatment (30 for PD; 1 for subject decision). A maximum tolerated dose has not been reached. The most common treatment-related adverse events (TR-AEs) were: fatigue (21.9%); nausea (15.6%), and infusion-related reactions (9.4%). Grade (Gr) ≥3 TR-AEs occurred in 2 patients (6.25%): anemia and asthenia (both Gr 3, occurring in 1 patient each). No Gr 4/5 TR-AEs and no protocol-defined DLTs were reported. No AE led to permanent study drug withdrawal; 5 patients died from PD, one within 30 days of their last dose. Thirty-one patients were evaluated for antitumor activity: using RECIST criteria, 1 PR (NSCLC; time on treatment = 324 days, ongoing) and 6 stable diseases (SD; median duration 42 days) were observed. 28 patients were evaluated by PET, with 2 (7%) FDG partial metabolic responses (EORTC criteria) seen. No difference was found between QW (used with select doses) and Q2W schedules for safety, antitumor activity, and PK/PD parameters. RO6874813 serum concentrations increased linearly with dose and revealed saturation of TMDD at ≥ 5 mg/kg (Q2W). For the single patient with a PR (30 mg/kg; Q2W), the Cmax at C1 exceeded that of other patients and showed accumulation over time, despite two dose interruptions for Gr 2 neutropenia. Blood BM analyses revealed a significant upregulation of TRAIL and ccCK18 after dosing in this and other patients, suggesting apoptotic activity. FAP and DR5 were expressed in tumor tissue of all patients. Conclusions: RO6874813 demonstrated a favorable safety profile in patients with multiple solid tumor types, and dose escalation and regimen optimization continue. Preliminary antitumor activity was observed in a patient with heavily pretreated NSCLC. Analyses required to support the hypothesis that FAP-binding mediates sufficiently high levels of DR5 clustering for apoptosis induction are ongoing. Citation Format: Johanna Bendell, Jean-Yves Blay, Philippe Cassier, Todd Bauer, Catherine Terret, Claudia Mueller, Anthony Morel, Evelyne Chesne, Zhi-xin Xu, Jean Tessier, Maurizio Ceppi, Ian James, Sabine Wilson, Elizabeth Quackenbush, Maria Ochoa de Olza, Josep Tabernero, Maria De Miguel, Emiliano Calvo. Phase 1 trial of RO6874813, a novel bispecific FAP-DR5 antibody, in patients with solid tumors [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A092.

BACKGROUND We conducted a phase 1 dose-escalation study of RO5323441, a novel antiplacental growth factor (PlGF) monoclonal antibody, to establish the recommended dose for use with bevacizumab and to investigate the pharmacokinetics, pharmacodynamics, safety/tolerability, and preliminary clinical efficacy of the combination. METHODS Twenty-two participants with histologically confirmed glioblastoma in first relapse were treated every 2 weeks with RO5323441 (625 mg, 1250 mg, or 2500 mg) plus bevacizumab (10 mg/kg). A standard 3 + 3 dose-escalation trial design was used. RESULTS RO5323441 combined with bevacizumab was generally well tolerated, and the maximum tolerated dose was not reached. Two participants experienced dose-limiting toxicities (grade 3 meningitis associated with spinal fluid leak [1250 mg] and grade 3 cerebral infarction [2500 mg]). Common adverse events included hypertension (14 participants, 64%), headache (12 participants, 55%), dysphonia (11 participants, 50%) and fatigue (6 participants, 27%). The pharmacokinetics of RO5323441 were linear, over-the-dose range, and bevacizumab exposure was unaffected by RO5323441 coadministration. Modulation of plasmatic angiogenic proteins, with increases in VEGFA and decreases in FLT4, was observed. Dynamic contrast-enhanced/diffusion-weighted MRI revealed large decreases in vascular parameters that were maintained through the dosing period. Combination therapy achieved an overall response rate of 22.7%, including one complete response, and median progression-free and overall survival of 3.5 and 8.5 months, respectively. CONCLUSION The toxicity profile of RO5323441 plus bevacizumab was acceptable and manageable. The observed clinical activity of the combination does not appear to improve on that obtained with single-agent bevacizumab in patients with recurrent glioblastoma.

Background Inhibition of mitogen-activated protein kinase (MEK, also known as MAPK2, MAPKK), a key molecule of the Ras/MAPK (mitogen-activated protein kinase) pathway, has shown promising effects on B-raf-mutated and some RAS (rat sarcoma)-activated tumors in clinical trials. The objective of this study is to examine the efficacy of a novel allosteric MEK inhibitor RO4987655 in K-ras-mutated human tumor xenograft models using [18F] FDG-PET imaging and proteomics technology. Methods [18F] FDG uptake was studied in human lung carcinoma xenografts from day 0 to day 9 of RO4987655 therapy using microPET Focus 120 (CTI Concorde Microsystems, Knoxville, TN, USA). The expression levels of GLUT1 and hexokinase 1 were examined using semi-quantitative fluorescent immunohistochemistry (fIHC). The in vivo effects of RO4987655 on MAPK/PI3K pathway components were assessed by reverse phase protein arrays (RPPA). Results We have observed modest metabolic decreases in tumor [18F] FDG uptake after MEK inhibition by RO4987655 as early as 2 h post-treatment. The greatest [18F] FDG decreases were found on day 1, followed by a rebound in [18F] FDG uptake on day 3 in parallel with decreasing tumor volumes. Molecular analysis of the tumors by fIHC did not reveal statistically significant correlations of GLUT1 and hexokinase 1 expressions with the [18F] FDG changes. RPPA signaling response profiling revealed not only down-regulation of pERK1/2, pMKK4, and pmTOR on day 1 after RO4987655 treatment but also significant up-regulation of pMEK1/2, pMEK2, pC-RAF, and pAKT on day 3. The up-regulation of these markers is interpreted to be indicative of a reactivation of the MAPK and activation of the compensatory PI3K pathway, which can also explain the rebound in [18F] FDG uptake following MEK inhibition with RO4987655 in the K-ras-mutated human tumor xenografts. Conclusions We have performed the first preclinical evaluation of a new MEK inhibitor, RO4987655, using a combination of [18F] FDG-PET imaging and molecular proteomics. These results provide support for using preclinical [18F] FDG-PET imaging in early, non-invasive monitoring of the effects of MEK and perhaps other Ras/MAPK signaling pathway inhibitors, which should facilitate a wider implementation of clinical [18F] FDG-PET to optimize their clinical use. Electronic supplementary material The online version of this article (doi:10.1186/s13550-014-0034-6) contains supplementary material, which is available to authorized users.

Consistent longitudinal segmentation of brain tumor images is a critical issue in treatment monitoring and in clinical trials. Fully automatic segmentation methods are a good candidate for reliably detecting changes of tumor volume over time. We propose an integrated 4D spatio-temporal brain tumor segmentation method, which combines supervised classification with conditional random field regularization in an energy minimization scheme. Promising results and improvements over classic 3D methods for monitoring the temporal volumetric evolution of necrotic, active and edema tumor compartments are demonstrated on a longitudinal dataset of glioma patient images from a multi-center clinical trial. Thanks to its speed and simplicity the approach is a good candidate for standard clinical use.

Purpose: This phase I study of the mitogen-activated protein/extracellular signal–regulated kinase inhibitor RO4987655 (CH4987655) assessed its maximum tolerated dose (MTD), dose-limiting toxicities (DLT), safety, pharmacokinetic/pharmacodynamic profile, and antitumor activity in patients with advanced solid tumors. Patients and Methods: An initial dose escalation was conducted using a once-daily dosing schedule, with oral RO4987655 administered at doses of 1.0 to 2.5 mg once daily over 28 consecutive days in 4-week cycles. Doses were then escalated from 3.0 to 21.0 mg [total daily dose (TDD)] using a twice-daily dosing schedule. Results: Forty-nine patients were enrolled. DLTs were blurred vision (n = 1) and elevated creatine phosphokinase (n = 3). The MTD was 8.5 mg twice daily (TDD, 17.0 mg). Rash-related toxicity (91.8%) and gastrointestinal disorders (69.4%) were the most frequent adverse events. The pharmacokinetic profile of RO4987655 showed dose linearity and a half-life of approximately 4 hours. At the MTD, target inhibition, assessed by suppression of extracellular signal–regulated kinase phosphorylation in peripheral blood mononuclear cells, was high (mean 75%) and sustained (90% of time >IC50). Of the patients evaluable for response, clinical benefit was seen in 21.1%, including two partial responses (one confirmed and one unconfirmed). 79.4% of patients showed a reduction in fluorodeoxyglucose uptake by positron emission tomography between baseline and day 15. Conclusion: In this population of heavily pretreated patients, oral RO4987655 showed manageable toxicity, a favorable pharmacokinetics/pharmacodynamics profile, and promising preliminary antitumor activity, which has been further investigated in specific populations of patients with RAS and/or RAF mutation driven tumors. Clin Cancer Res; 18(17); 4794–805. ©2012 AACR.

e13508 Background: Tumor size change from baseline (RECIST) is often used to assess antitumor activity of investigational agents in phase 1 trials, but this measure does not take into account the tumor growth rate (TGR) prior to treatment. TGR could be highly variable in a phase 1 ‘all-comers’ patient population, with a high TGR potentially masking a meaningful treatment effect (TE). Assessing the change in TGR (Mehrara et al, BJC 2011) using historical tumor burden assessments (Gomez-Roca et al, Eur J Cancer 2011) may provide higher sensitivity to true TE (TTE). The objectives of the current study are to formalize a Growth Rate Based Method (GRBM) and to compare, using simulated patients, the ability of GRBM and RECIST assessments to detect and quantify TTE. Methods: The exponential tumor growth model (Claret et al, J Clin Oncol. 2009) was used to simulate the sum of the longest diameters (SLD) individual time courses of 2000 virtual patients under different TGR scenarios: slow, medium, fast and ‘all comers’ (highly variable TGR as often encountered in phase 1). Different sampling designs were simulated wherein tumor assessments with measurement errors were obtained, ranging from 16 to 4 weeks prior to treatment initiation (TI), immediately before TI, and 8 and 16 weeks after TI. TTE was defined as the difference between the simulated SLDs at 16 weeks with and without treatment. GRBM response was defined as the model-predicted difference between the SLDs with and without treatment, as estimated from the simulated samples. Sensitivity (Se) of RECIST or GRBM was defined as the probability of classifying a patient as a RECIST or GRBM >30% reduction when the TTE >30%, and specificity (Sp) as the probability of RECIST or GRBM reduction

2092 Background: BV inhibits VEGF and is approved for progressive GBM following prior therapy. The placental growth factor (PlGF) is a member of the VEGF family and PlGF expression has been shown to correlate with tumor stage and survival in several human malignancies. In cancer patients (pts) PlGF is up-regulated upon treatment with VEGF inhibitors. RO is a humanized IgG1 mAb directed against PlGF that has demonstrated antitumor activity in an orthotopic GBM model. Single agent RO was previously tested in advanced solid tumors. Methods: Eligibility criteria included histologically confirmed GBM with documented radiographic progression upon front line therapy, ≥18 years of age, KPS ≥70, adequate bone marrow reserve and organ function. Prior treatment with VEGF/PLGF targeted therapies was not permitted. Three to six pts were enrolled per dose level (DL), the MTD defined as the dose with DLTs ≤ 1/6 pts during 28-days of cycle 1, using CTCAE v4. Results: A total of 22 pts (16m/6f) have been enrolled in 3 DLs: RO 625mg (4 pts), 1250mg (6), and 2500mg (12) IV every 2 weeks (q2w), each in combination with BV 10mg/kg IV q2w. Median age: 58 years (range 37-72). RO serum concentrations increased proportionally, while serum exposures of BV were similar between all DLs. Two pts experienced a DLT: Meningitis G3 (1250 mg) and cerebral infarction G3 (2500 mg). Most commonly reported adverse events included hypertension (14 pts), headache (11), dysphonia (10), fatigue (6), nasopharyngitis (5), epistaxis (4), constipation (4), nausea (3), and arthralgia (3). Across all DLs tested, the overall response rate by RANO criteria was 22.7%. Conclusions: The tolerability of RO in combination with BV is acceptable; a MTD was not determined. Anti-PlGF treatment does not appear to add on clinical activity observed for single agent BV in recurrent GBM. Clinical trial information: NCT01308684.

3017 Background: Mutations of Ras/Raf lead to a sustained and constitutive activation of ERK pathway. MEK1/2 is the only enzyme that activates ERK1/2; consequently MEK1/2 is a potential target to inhibit in cancers with an activated ERK pathway. RO4987655, a potent, highly selective ATP non-competitive MEK1i with an excellent selectivity profile, was tested in a 3+3 Ph1 study design. Objectives were determination of maximum tolerated dose (MTD), recommended Ph2 dose (RP2D), dose limiting toxicities (DLTs), safety/tolerability, PK/ PD and clinical activity. Methods: Patients (pts) with advanced/metastatic solid tumors received oral RO4987655 administered on a continuous daily dosing (QD) from 1-2.5 mg then twice daily (BID) from 3-21 mg total daily dose in 28 days (D) cycles. Blood PK samples were collected on cycle 1 (C1) [D 1, 8, 15 and 22]. Molecular target suppression was measured by pERKi in PBMC on C1 (D1, D15). Paired skin and tumor biopsies (optional) (baseline, C1D15) and sequential FDG-PET scans ...

3006^ Background: The Ras-Raf-MEK-extra-cellular signal-regulated kinase 1 and 2 (ERK1/2) pathway is frequently deregulated in human cancer. RO5126766, a first-in-class, dual Raf/MEK inhibitor was tested in a phase I (Ph1) study. Objectives were determination of maximum tolerated dose (MTD), dose-limiting toxicities (DLTs), recommended phase II dose (RP2D), safety/tolerability, PK/PD and clinical activity. Methods: Patients (pts) with advanced or metastatic solid tumors received oral RO5126766 once daily (QD) in 28 day cycles. To increase the therapeutic window, 2 intermittent regimens were also evaluated: 7 days on/7 days off (7/7) and 4 days on/3 days off (4/3). PK and PD samples (PBMCs) were collected after a single run-in dose and on cycle 1 day 15 (C1D15). Paired skin and tumor biopsies (baseline, C1D15) were analyzed for mutational status and target inhibition. FDG-PET scans (baseline, C1D15, and C3D1) were performed. Results: 52 pts (25 QD, 13 4/3 and 14 7/7) were enrolled in 13 cohorts (QD: 0.1 - ...

The preparation is described of pure (S)-2-hydroxy-2-(3-phenoxyphenyl)acetonitrile (the alcohol component of some very active pyrethroids) from the racemic form of this 2-hydroxyacetonitrile. The new resolution process is based on differences in physical properties of two diastereoisomeric ethers. The resolving agents used are chiral hemiacetal compounds; one of these, 4-hydroxy-6,6-dimethyl-3-oxabicyclo[3.1.0]hexan-2-one, is available from an industrial synthesis of chrysanthemic acid, and appears specially useful for a two-step resolution of many racemic alcohols, even base-sensitive types.

Natural pyrethric acid has the (1R, trans )-E geometry: the three other possible (lR)-isomers produce esters with weak insecticidal activity. The situation is very different when the vinylic methyl group of the chain is removed: (1R, trans )-E,(lR, trans )-Z, and (1R, cis )-E isomers give rather inactive “nor-pyrethric” esters, while the (1R, cis )-Z configuration leads to more potent diesters. Activity can be further improved by selection of alkyl groups specially suited to the alcoholic pyrethroid moiety. Pesticide properties can also be modulated towards knock-down effect and activity against acarians and cattle-ticks. Another attractive point is an exceptional phostostability of the ( 1R , cis )-Z “nor-pyrethric” moiety leading to excellent persistence towards sunlight for most of the diesters in the new series. Several synthetic routes are presented starting from ( 1R , cis )-caronaldehyde, a stepping-stone in the deltamethrin synthesis.

Background Positron emission tomography (PET) with [2-18 F]-2-fluoro-2-deoxy-D-glucose ([18 F]FDG-PET) was acquired at multiple time-points a) to monitor the early response to RO5126766 (CH5126766) in xenograft models b) to evaluate non-invasive small animal [18 F]FDG-PET imaging as a biomarker for MEK inhibitors for translation into dose-finding studies in cancer patients and c) to explore the underlying mechanism related to FDG uptake in tumors treated with RO5126766. Methods [18 F]FDG uptake was studied in HCT116 (K-ras), COLO205 (B-raf) mutants and COLO320DM (wild type) xenografts from day 0 to 3 of RO5126766 treatment using a microPET Focus 120 and complemented with in vitro incubations, ex-vivo phosphor imaging and immunohistochemical (IHC) analyses. Results In the HCT116 (K-ras) and COLO205 (B-raf) mutant xenografts, significant decreases in [18 F]FDG uptake were detected in vivo on day 1 with 0.3 mg/kg and ex vivo on day 3 with 0.1 mg/kg RO5126766. [18 F]FDG changes correlated with decreases in tumor cells proliferation (Ki-67) and with changes in expression levels of GLUT1. No effects were observed in drug resistant COLO320DM cells. The cellular fractionation and Western blotting analyses suggested that the change of [18 F]FDG uptake associated with RO5126766 is due to translocation of GLUT1 from membrane to cytosol, similar to the results reported in the literature with EGFR tyrosine kinase inhibitors, which also target the MAPK pathway. Conclusions RO5126766 inhibition resulted in a rapid time - and dose - dependent decline in [18 F]FDG uptake in both mutant xenografts. These results strongly resemble the clinical observations obtained with MEK/Raf inhibitors support the use of preclinical [18 F]FDG-PET as a translational tool for decision support in preclinical and early clinical development of MEK inhibitors.