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A study was conducted to evaluate the efficacy of the use of cetuximab and irinotecan, fluorouracil and leucovorin (FOLFIRI) as a first-line of treatment for metastatic colorectal cancer. Results indicated that a combination of cetuximab with FOLFIRI was more effective in reducing the progress of the cancer as compared to FOLFIRI alone.

Tepotinib is a highly selective and potent MET inhibitor in development for the treatment of patients with solid tumors. Given the favorable tolerability and safety profiles up to the maximum tested dose in the first‐in‐human (FIH) trial, an efficacy‐driven translational modeling approach was proposed to establish the recommended phase II dose (RP2D). To study the in vivo pharmacokinetics (PKs)/target inhibition/tumor growth inhibition relationship, a subcutaneous KP‐4 pancreatic cell‐line xenograft model in mice with sensitivity to MET pathway inhibition was selected as a surrogate tumor model. Further clinical PK and target inhibition data (derived from predose and postdose paired tumor biopsies) from a FIH study were integrated with the longitudinal PKs and target inhibition profiles from the mouse xenograft study to establish a translational PK/pharmacodynamic (PD) model. Preclinical data showed that tumor regression with tepotinib treatment in KP‐4 xenograft tumors corresponded to 95% target inhibition. We therefore concluded that a PD criterion of sustained, near‐to‐complete (>95%) phospho‐MET inhibition in tumors should be targeted for tepotinib to be effective. Simulations of dose‐dependent target inhibition profiles in human tumors that exceeded the PD threshold in more than 90% of patients established an RP2D of tepotinib 500 mg once daily. This translational mathematical modeling approach supports an efficacy‐driven rationale for tepotinib phase II dose selection of 500 mg once daily. Tepotinib at this dose has obtained regulatory approval for the treatment of patients with non‐small cell lung cancer harboring MET exon 14 skipping. [ABSTRACT FROM AUTHOR]

Background: Oncology nurse navigators are integral members of multidisciplinary teams that manage patients with non--small cell lung cancer (NSCLC), including the 3%-4% of patients with mesenchymal-epithelial transition exon 14 (METex14) skipping mutation. This oncogenic driver confers a poor prognosis but sensitizes tumors to MET inhibitors. Tepotinib, an oral, selective MET inhibitor, showed robust, durable efficacy in METex14 NSCLC in the VISION trial. Objective: To support nurse navigators and other professionals managing these patients, we conducted an exploratory analysis of VISION to evaluate circulating tumor DNA (ctDNA) and MET-related biomarkers in liquid biopsy (LBx [ie, blood]) samples and their associations with clinical outcomes. Methods: Baseline, on-treatment and/or end-of-treatment (EOT) LBx from VISION were analyzed by ctDNA next-generation sequencing (NGS; Guardant360®) and enzyme-linked immunoassay for shed MET (sMET; a soluble form of the MET extracellular domain) and hepatocyte growth factor (HGF; the ligand for MET). Patients with baseline LBx NGS profiles (n=165) were classified as positive (L+) or negative (L-) for METex14 (all L- patients had METex14 by tissue NGS). On-treatment response was analyzed in L+ patients with 2 consecutive on-treatment samples (n=81). Confirmed molecular response (cMR) was defined as >75% depletion from baseline in METex14 variant allele frequency (VAF) in 2 consecutive on-treatment samples; molecular progression (MP) was defined as VAF increase from baseline in ≥1 on-treatment sample. Objective response rate (ORR), median duration of response (mDOR), median progression-free survival (mPFS), and median overall survival (mOS) were evaluated according to biomarker status. Mechanisms of acquired resistance were investigated in postprogression EOT samples. Data cut-off date was November 20, 2022. Results: Patients with high (>upper quartile, n=58) versus low (≤upper quartile, n=175) baseline HGF had numerically shorter mDOR and mPFS. Patients with low (≤lower quartile, n=61) versus high (>lower quartile, n=183) relative change in sMET from baseline had numerically higher ORR, mPFS, and mOS. In L- (n=51) versus L+ (n=114) patients, ORR was comparable, but mDOR and mPFS were longer. Seven of 10 patients with MET amplification, 1 of 5 patients with KRAS/NRAS mutation, 1 of 5 patients with PI3K/AKT pathway alterations, and 0 of 2 patients with EGFR mutations at baseline had objective response. Patients with tumor protein 53 (TP53) mutations (73/165) versus wild-type had comparable ORR but shorter mPFS (8.2 vs 11.3 mo, respectively). Patients with cMR (n=65 [80%]) versus MP (n=12 [15%]) had better outcomes (ORR: 63.1% vs 16.7%, respectively; mDOR: 18.5 vs 6.2 mo, respectively; mPFS: 11.2 vs 4.2 mo, respectively). At EOT, 9 of 73 patients (12%) had acquired MET kinase domain mutations and 9 of 73 (12%) had emerging alterations in KRAS, EGFR, MYC, BRAF, RB1, and ERBB2. Conclusions: In the largest on-treatment LBx biomarker dataset for an MET inhibitor in METex14 NSCLC, MR was associated with improved outcomes and TP53 mutation had negative prognostic significance. On-target secondary MET mutations and off-target bypass pathway activation were potential resistance mechanisms. These data can help to inform nurse navigators and other healthcare professionals managing patients receiving tepotinib for METex14 skipping NSCLC. [ABSTRACT FROM AUTHOR]

In many cancers, a high constitutive activation of transcription factor NF-?B has been implicated in tumor progression and apoptosis resistance, making NF-?B an attractive target for cancer therapy. Here, we describe the specific inhibition of NF-?B by the intracellular delivery of I?Ba through VP22-mediated protein transduction. The Herpes virus protein VP22 has attracted great attention in gene therapy, because of its ability to migrate from an original expressing cell into surrounding recipient cells, resulting in high levels of protein transduction. To evaluate the use of VP22 as a vehicle for NF-?B inhibition, we expressed several versions of VP22-I?Ba fusion proteins in baculovirus, bacteria, and mammalian cells. While we could not detect transcellular migration of different VP22-I?Ba constructs, interestingly, baculovirally expressed VP22-I?Ba was efficiently delivered into cells after exogenous administration. The purified and imported VP22-I?Ba retained its function and efficiently inhibited both constitutive and inducible NF-?B activation. We further show that the 34 C-terminal amino acids of VP22 were sufficient for the import property, suggesting also that the ability of intercellular migration and cellular import are not linked to each other. Together, our results demonstrate that recombinant VP22 acts as an efficient vehicle for the exogenous delivery of I?Ba and, moreover, might find applications to block NF-?B activation specifically.Oncogene (2003) 22, 5367-5373. doi:10.1038/sj.onc.1206544 [ABSTRACT FROM AUTHOR]

Editorial. Discusses the ever increasing list of caspase substrates. Identification of caspase targets; Elucidation of the consequences of proteolytic cleavage; Requirements which an apoptosis-relevant caspase substrate should meet.

The effects of the liver tumor promoters phenobarbital, clofibrate, dieldrin, and DDT on transforming growth factor-β1 (TGFβ)-induced apoptosis were studied in FTO-2B hepatoma cells. Inhibition of apoptosis by these compounds was strongly correlated with a decrease in CPP32-like caspase activity. Similar effects were obtained with insulin and dexamethasone. CPP32-like activity may thus provide a useful tool for quantiation of apoptosis under various treatment conditions. Diverse effects on apoptosis-associated cellular signaling proteins were observed: insulin led to an activation of the MAP kinases ERK1/2, of PKB/Akt and of NF-κB, phenobarbital and clofibrate enhanced NF-κB activity solely, while dexamethasone slightly enhanced NF-κB activity and increased the expression of Bcl-X[sub L]. Since inhibition of apoptosis was still detectable if the anti-apoptotic compounds were administered more than 10 h after TGFβ, the diverse primary signals appear to converge at a presumably late stage of apoptosis, but upstream of activation of CPP32 or related caspases. [ABSTRACT FROM AUTHOR]

High-level MET amplification (METamp) is a primary driver in ∼1%-2% of non-small cell lung cancers (NSCLCs). Cohort B of the phase 2 VISION trial evaluates tepotinib, an oral MET inhibitor, in patients with advanced NSCLC with high-level METamp who were enrolled by liquid biopsy. While the study was halted before the enrollment of the planned 60 patients, the results of 24 enrolled patients are presented here. The objective response rate (ORR) is 41.7% (95% confidence interval [CI], 22.1-63.4), and the median duration of response is 14.3 months (95% CI, 2.8-not estimable). In exploratory biomarker analyses, focal METamp, RB1 wild-type, MYC diploidy, low circulating tumor DNA (ctDNA) burden at baseline, and early molecular response are associated with better outcomes. Adverse events include edema (composite term; any grade: 58.3%; grade 3: 12.5%) and constipation (any grade: 41.7%; grade 3: 4.2%). Tepotinib provides antitumor activity in high-level METamp NSCLC (ClinicalTrials.gov: NCT02864992)., Competing Interests: Declaration of interests X.L. reported personal/consulting fees from EMD Serono during the conduct of the study; personal or consulting fees from AstraZeneca, Spectrum Pharmaceuticals, Novartis, Eli Lilly, Boehringer Ingelheim, Janssen, Blueprint Medicines, Bayer, and Albion; grants from ArriVent, Eli Lilly, Boehringer Ingelheim, and Regeneron; and personal fees from AbbVie outside the submitted work. L.G.P.-A. reported consulting roles with AstraZeneca, Lilly, EMD Serono, Spectrum Pharmaceuticals, and Daiichi Sankyo/Eli Lilly; research funding from Lilly and Boehringer Ingelheim; leadership roles from Genomica and ALTUM Sequencing; speakers bureau from Merck & Co., Kenilworth, NJ, Bristol-Myers Squibb, Roche, Pfizer, Lilly, AstraZeneca, and the healthcare business of Merck KGaA, Darmstadt, Germany; travel/accommodations/expenses from Roche, AstraZeneca, Merck & Co., Kenilworth, NJ, Bristol-Myers Squibb, Pfizer, and Takeda; and honoraria from Roche, Lilly, Pfizer, Bristol-Myers Squibb, Merck & Co., Kenilworth, NJ, AstraZeneca, the healthcare business of Merck KGaA, Darmstadt, Germany, PharmaMar, Novartis, Celgene, Amgen, Sanofi, Ipsen, Servier, Bayer, Blueprint Medicines, Mirati Therapeutics, and Takeda outside the submitted work. J.V.M. reported an advisory role with Amgen outside the submitted work. S.V. reported consulting or advisory role from the healthcare business of Merck KGaA, Darmstadt, Germany, AbbVie, Bristol-Myers Squibb, AstraZeneca, Merck & Co., Kenilworth, NJ, and Roche; non-financial support from OSE Immunotherapeutics; and personal fees from Janssen and Puma Biotechnology outside the submitted work. C.C.G. reported a consulting/advisory role with Boehringer Ingelheim and travel/accommodations/expenses from Roche and Merck & Co., Kenilworth, NJ, outside the submitted work. E.F.S. reported an advisory/consultancy role (institution) with Eli Lilly, AstraZeneca, Boehringer Ingelheim, Roche/Genentech, Bristol-Myers Squibb, the healthcare business of Merck KGaA, Darmstadt, Germany, Merck & Co., Kenilworth, NJ, Takeda, Bayer, Regeneron, Novartis, Daiichi Sankyo, and Seattle Genetics; and research funding (institution) from Boehringer Ingelheim, Bayer, Roche/Genentech, AstraZeneca, and Bristol-Myers Squibb outside the submitted work. M.G. reported personal fees from the healthcare business of Merck KGaA, Darmstadt, Germany, during the conduct of the study; grants and personal fees from AstraZeneca; and personal fees from the healthcare business of Merck KGaA, Darmstadt, Germany, Bayer, Bristol-Myers Squibb, AbbVie, Takeda, Janssen, Roche, Sanofi, Boehringer Ingelheim, Daiichi Sankyo, Eli Lilly, Novartis, and Blueprint outside the submitted work. R.V. reported research funding from the healthcare business of Merck KGaA, Darmstadt, Germany, during the conduct of the study; personal consulting fees from Janssen; personal speaker fees from Bristol-Myers Squibb and Takeda; personal speaker bureau fees from Amgen, Sanofi, Roche, and AstraZeneca; and travel fees from Pfizer Travel and Janssen outside the submitted work. D.V.B. reported advisory/consultancy honoraria from Roche, the healthcare business of Merck KGaA, Darmstadt, Germany, Bristol-Myers Squibb, AstraZeneca, Pfizer, Boehringer Ingelheim, and Takeda; and speaker honoraria from Roche, the healthcare business of Merck, KGaA, Darmstadt, Germany, Bristol-Myers Squibb, AstraZeneca, Pfizer, and Boehringer Ingelheim outside the submitted work. J.F.P. reported consulting/advisory roles with Roche, AstraZeneca, Boehringer Ingelheim, Bristol-Myers Squibb, Merck & Co., Kenilworth, NJ, and GlaxoSmithKline outside the submitted work. M.S. reported an advisory/consulting role with Roche, AstraZeneca, Bristol-Myers Squibb, and Merck & Co., Kenilworth, NJ, outside the submitted work. T.K. reported grants and personal fees from Chugai Pharmaceutical Co., AstraZeneca, Eli Lilly Japan, Taiho Pharmaceutical Co., Bristol-Myers Squibb, Merck & Co., Kenilworth, NJ, and Kyowa Hakko Kirin; personal fees from Ono Pharmaceutical, Pfizer Japan, Nippon Boehringer Ingelheim, Nippon Kayaku, Novartis, and Daiichi-Sankyo; and grants from the healthcare business of Merck KGaA, Darmstadt, Germany, outside the submitted work. Y.-C.K. reported honoraria from AstraZeneca, Roche, Boehringer Ingelheim, Merck & Co., Kenilworth, NJ, Pfizer, Ono, Bristol-Myers Squibb, Daiichi Sankyo, and Yuhan; and research funding from AstraZeneca, Roche, and Boehringer Ingelheim outside the submitted work. S.S.Y. reported honoraria from AstraZeneca, Roche, Boehringer Ingelheim, Merck & Co., Kenilworth, NJ, Pfizer, Ono Pharmaceutical, Bristol-Myers Squibb, Daiichi Sankyo, and Yuhan; and research funding from AstraZeneca, Roche, and Boehringer Ingelheim outside the submitted work. J.-Y.H. reported research funding from Hoffmann-La Roche, Ltd., Ono Pharmaceutical, Pfizer, and Takeda outside the submitted work. J.-H.K. reported honoraria from Roche, Boehringer Ingelheim, Merck & Co., Kenilworth, NJ, and Bristol-Myers Squibb; consulting roles with Roche, Boehringer Ingelheim, Merck & Co., Kenilworth, NJ, AstraZeneca, and Yuhan; speakers bureau for Pfizer, Merck & Co., Kenilworth, NJ, and Roche; and research funding from Boehringer Ingelheim, AstraZeneca, Daiichi Sankyo, and Yuhan outside the submitted work. Y.J.C. reported consulting/advisory role with Astella, Yuhan, Merck & Co., Kenilworth, NJ, Roche, and Chong Kun Dang outside the submitted work. C.S. is an employee of the healthcare business of Merck KGaA, Darmstadt, Germany. D.J. is an employee of the healthcare business of Merck KGaA, Darmstadt, Germany, and holds stock in Merck KGaA, Darmstadt, Germany. H.V. is an employee of the healthcare business of Merck KGaA, Darmstadt, Germany. R.B. is an employee of the healthcare business of Merck KGaA, Darmstadt, Germany, and holds stock in Merck KGaA, Darmstadt, Germany. G.O. was an employee of the healthcare business of Merck KGaA, Darmstadt, Germany, at the time of the study and holds stock in Novartis. A.J. is an employee of the healthcare business of Merck KGaA, Darmstadt, Germany, and holds stock in Merck KGaA, Darmstadt, Germany. P.K.P. reported an advisory/consulting role from Takeda, Xencor, Janssen, CrownBio, Bicara, Mirati, and EMD Serono; and research funding (institution) from Bicara, Boehringer Ingelheim, and EMD Serono outside the submitted work., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

The mesenchymal-epithelial transition factor (MET) proto-oncogene encodes the MET receptor tyrosine kinase. MET aberrations drive tumorigenesis in several cancer types through a variety of molecular mechanisms, including MET mutations, gene amplification, rearrangement, and overexpression. Therefore, MET is a therapeutic target and the selective type Ib MET inhibitor, tepotinib, was designed to potently inhibit MET kinase activity. In vitro, tepotinib inhibits MET in a concentration-dependent manner irrespective of the mode of MET activation, and in vivo, tepotinib exhibits marked, dose-dependent antitumor activity in MET-dependent tumor models of various cancer indications. Tepotinib penetrates the blood-brain barrier and demonstrates strong antitumor activity in subcutaneous and orthotopic brain metastasis models, in-line with clinical activity observed in patients. MET amplification is an established mechanism of resistance to EGFR tyrosine kinase inhibitors (TKI), and preclinical studies show that tepotinib in combination with EGFR TKIs can overcome this resistance. Tepotinib is currently approved for the treatment of adult patients with advanced or metastatic non-small cell lung cancer harboring MET exon 14 skipping alterations. This review focuses on the pharmacology of tepotinib in preclinical cancer models harboring MET alterations and demonstrates that strong adherence to the principles of the Pharmacological Audit Trail may result in a successful discovery and development of a precision medicine., (©2023 The Authors; Published by the American Association for Cancer Research.)

Background: A splice-site mutation that results in a loss of transcription of exon 14 in the oncogenic driver MET occurs in 3 to 4% of patients with non-small-cell lung cancer (NSCLC). We evaluated the efficacy and safety of tepotinib, a highly selective MET inhibitor, in this patient population., Methods: In this open-label, phase 2 study, we administered tepotinib (at a dose of 500 mg) once daily in patients with advanced or metastatic NSCLC with a confirmed MET exon 14 skipping mutation. The primary end point was the objective response by independent review among patients who had undergone at least 9 months of follow-up. The response was also analyzed according to whether the presence of a MET exon 14 skipping mutation was detected on liquid biopsy or tissue biopsy., Results: As of January 1, 2020, a total of 152 patients had received tepotinib, and 99 patients had been followed for at least 9 months. The response rate by independent review was 46% (95% confidence interval [CI], 36 to 57), with a median duration of response of 11.1 months (95% CI, 7.2 to could not be estimated) in the combined-biopsy group. The response rate was 48% (95% CI, 36 to 61) among 66 patients in the liquid-biopsy group and 50% (95% CI, 37 to 63) among 60 patients in the tissue-biopsy group; 27 patients had positive results according to both methods. The investigator-assessed response rate was 56% (95% CI, 45 to 66) and was similar regardless of the previous therapy received for advanced or metastatic disease. Adverse events of grade 3 or higher that were considered by investigators to be related to tepotinib therapy were reported in 28% of the patients, including peripheral edema in 7%. Adverse events led to permanent discontinuation of tepotinib in 11% of the patients. A molecular response, as measured in circulating free DNA, was observed in 67% of the patients with matched liquid-biopsy samples at baseline and during treatment., Conclusions: Among patients with advanced NSCLC with a confirmed MET exon 14 skipping mutation, the use of tepotinib was associated with a partial response in approximately half the patients. Peripheral edema was the main toxic effect of grade 3 or higher. (Funded by Merck [Darmstadt, Germany]; VISION ClinicalTrials.gov number, NCT02864992.)., (Copyright © 2020 Massachusetts Medical Society.)

Radiotherapy (RT) along with surgery is the mainstay of treatment in head and neck squamous cell carcinoma (HNSCC). Radioresistance represents a major source of treatment failure, underlining the urgent necessity to explore and implement effective radiosensitization strategies. The MET receptor widely participates in the acquisition and maintenance of an aggressive phenotype in HNSCC and modulates the DNA damage response following ionizing radiation (IR). Here, we assessed MET expression and mutation status in primary and metastatic lesions within a cohort of patients with advanced HNSCC. Moreover, we investigated the radiosensitization potential of the MET inhibitor tepotinib in a panel of cell lines, in vitro and in vivo , as well as in ex vivo patient-derived organotypic tissue cultures (OTC). MET was highly expressed in 62.4% of primary tumors and in 53.6% of lymph node metastases (LNM), and in 6 of 9 evaluated cell lines. MET expression in primaries and LNMs was significantly associated with decreased disease control in univariate survival analyses. Tepotinib abrogated MET phosphorylation and to distinct extent MET downstream signaling. Pretreatment with tepotinib resulted in variable radiosensitization, enhanced DNA damage, cell death, and G 2 -M-phase arrest. Combination of tepotinib with IR led to significant radiosensitization in one of two tested in vivo models. OTCs revealed differential patterns of response toward tepotinib, irradiation, and combination of both modalities. The molecular basis of tepotinib-mediated radiosensitization was studied by a CyTOF-based single-cell mass cytometry approach, which uncovered that MET inhibition modulated PI3K activity in cells radiosensitized by tepotinib but not in the resistant ones., (©2019 American Association for Cancer Research.)

Purpose: Approved anti-EGFR antibodies cetuximab and panitumumab provide significant clinical benefit in patients with metastatic colorectal cancer (MCRC). However, patients ultimately develop disease progression, often driven by acquisition of mutations in the extracellular domain (ECD) of EGFR. Sym004 is a novel 1:1 mixture of two nonoverlapping anti-EGFR mAbs that recently showed promising clinical activity in a phase I trial in MCRC. Our aim was to determine the efficacy of Sym004 to circumvent cetuximab resistance driven by EGFR ECD mutations., Experimental Design: Functional studies were performed to assess drug-receptor binding as well as ligand-dependent activation of individual EGFR mutants in the presence of cetuximab, panitumumab, and Sym004. Cell viability and molecular effects of the drugs were assayed in cetuximab-resistant cell lines and in tumor xenograft models. Efficacy of Sym004 was evaluated in patients progressing to cetuximab that harbored EGFR mutation in the post-cetuximab tumor sample., Results: Contrary to cetuximab and panitumumab, Sym004 effectively bound and abrogated ligand-induced phosphorylation of all individual EGFR mutants. Cells resistant to cetuximab harboring mutations in EGFR maintained sensitivity to Sym004, which was consistent with an effective suppression of EGFR downstream signaling, translating into profound and sustained tumor regression in the xenograft model. As proof-of-principle, a patient with a tumor harboring an EGFR mutation (G465R) following cetuximab therapy benefited from Sym004 therapy., Conclusions: Sym004 is an active drug in MCRC resistant to cetuximab/panitumumab mediated by EGFR mutations. EGFR mutations are potential biomarkers of response to Sym004 to be evaluated in ongoing large clinical trials. Clin Cancer Res; 22(13); 3260-7. ©2016 AACR., (©2016 American Association for Cancer Research.)

Purpose: To explore in a panel of patient-derived xenograft models of human non-small cell lung cancer (NSCLC) whether high EGFR expression, was associated with cetuximab activity., Experimental Design: NSCLC patient-derived xenograft models (n=45) were implanted subcutaneously into panels of nude mice and randomization cohorts were treated with either cetuximab, cisplatin, cisplatin plus cetuximab, vehicle control, or else were left untreated. Responses according to treatment were assessed at week 3 by analyzing the relative change in tumor volume and an experimental analogue of the Response Evaluation Criteria in Solid Tumors (RECIST) guidelines. An EGFR IHC score was calculated for each patient-derived xenograft model and response was assessed according to EGFR expression level., Results: When tumors were stratified into high and low EGFR expression groups (IHC score threshold 200; scale 0-300), a stronger antitumor activity was seen in the high EGFR expression group compared with the low EGFR expression group in both the cetuximab monotherapy and cisplatin plus cetuximab combination therapy settings. For tumors treated with cisplatin plus cetuximab, the objective response rate was significantly higher in the high EGFR expression group compared with the low EGFR expression group (68% vs. 29%). Objective response rates were similar in high and low expression groups for tumors treated with cisplatin alone (27% vs. 24%, respectively)., Conclusion: Cetuximab activity in NSCLC patient-derived xenograft models was demonstrated clearly only in tumors that expressed high levels of EGFR, as defined by an IHC score of ≥200., (©2014 American Association for Cancer Research.)

Purpose: This study assessed biomarkers for cetuximab efficacy in tissue samples collected during a phase I dose-escalation study exploring every second week administration of cetuximab as first-line therapy in patients with metastatic colorectal cancer (mCRC)., Patients and Methods: Sixty-two patients received cetuximab monotherapy for 6 weeks, followed by cetuximab plus infusional fluorouracil, leucovorin, and irinotecan until disease progression. Patients in the control arm received cetuximab as a 400 mg/m(2) initial dose then 250 mg/m(2) per week; patients in the dose-escalation arms received 400 to 700 mg/m(2) every second week. Tumor and skin biopsies were taken for immunohistochemical and microarray expression analyses (tumor only) at baseline and week 4. Plasma was collected for proteomic analysis at baseline and week 4. KRAS tumor mutation status was assessed., Results: In subsets of paired skin samples from 35 patients, cetuximab treatment was associated with substantial downregulation of phospho(p)-EGFR, p-MAPK and proliferation and substantial upregulation of p27(Kip1) and p-STAT3 levels. No marked difference in these effects was noted for different schedules of administration and dose levels. In the cetuximab monotherapy phase, responses were seen only in patients whose tumors were wild-type for KRAS (eight of 29 v zero of 19 for KRAS mutant tumors; P = .015). Progression-free survival was longer for patients with KRAS wild-type compared with KRAS mutant tumors (log-rank P = .048). Genomics/proteomics analyses (42 and 45 patients, respectively) identified candidate biomarkers associated with response., Conclusion: Biomarker analysis supported the functional equivalence of weekly and every second week administration of cetuximab and provided further confirmation that patients with KRAS wild-type mCRC were those most likely to benefit from cetuximab treatment.

Purpose: This randomized study assessed whether the best overall response rate (ORR) of cetuximab combined with oxaliplatin, leucovorin, and fluorouracil (FOLFOX-4) was superior to that of FOLFOX-4 alone as first-line treatment for metastatic colorectal cancer. The influence of KRAS mutation status was investigated., Patients and Methods: Patients received cetuximab (400 mg/m(2) initial dose followed by 250 mg/m(2)/wk thereafter) plus FOLFOX-4 (oxaliplatin 85 mg/m(2) on day 1, plus leucovorin 200 mg/m(2) and fluorouracil as a 400 mg/m(2) bolus followed by a 600 mg/m(2) infusion during 22 hours on days 1 and 2; n = 169) or FOLFOX-4 alone (n = 168). Treatment was continued until disease progression or unacceptable toxicity. KRAS mutation status was assessed in the subset of patients with assessable tumor samples (n = 233)., Results: The confirmed ORR for cetuximab plus FOLFOX-4 was higher than with FOLFOX-4 alone (46% v 36%). A statistically significant increase in the odds for a response with the addition of cetuximab to FOLFOX-4 could not be established (odds ratio = 1.52; P = .064). In patients with KRAS wild-type tumors, the addition of cetuximab to FOLFOX-4 was associated with a clinically significant increased chance of response (ORR = 61% v 37%; odds ratio = 2.54; P = .011) and a lower risk of disease progression (hazard ratio = 0.57; P = .0163) compared with FOLFOX-4 alone. Cetuximab plus FOLFOX-4 was generally well tolerated., Conclusion: KRAS mutational status was shown to be a highly predictive selection criterion in relation to the treatment decision regarding the addition of cetuximab to FOLFOX-4 for previously untreated patients with metastatic colorectal cancer.

Death ligands not only induce apoptosis but can also trigger necrosis with distinct biochemical and morphological features. We recently showed that in L929 cells CD95 ligation induces apoptosis, whereas TNF elicits necrosis. Treatment with anti-CD95 resulted in typical apoptosis characterized by caspase activation and DNA fragmentation. These events were barely induced by TNF, although TNF triggered cell death to a similar extent as CD95. Surprisingly, whereas the caspase inhibitor zVAD prevented CD95-mediated apoptosis, it potentiated TNF-induced necrosis. Cotreatment with TNF and zVAD was characterized by ATP depletion and accelerated necrosis. To investigate the mechanisms underlying TNF-induced cell death and its potentiation by zVAD, we examined the role of poly(ADP-ribose)polymerase-1 (PARP-1). TNF but not CD95 mediated PARP activation, whereas a PARP inhibitor suppressed TNF-induced necrosis and the sensitizing effect of zVAD. In addition, fibroblasts expressing a noncleavable PARP-1 mutant were more sensitive to TNF than wild-type cells. Our results indicate that TNF induces PARP activation leading to ATP depletion and subsequent necrosis. In contrast, in CD95-mediated apoptosis caspases cause PARP-1 cleavage and thereby maintain ATP levels. Because ATP is required for apoptosis, we suggest that PARP-1 cleavage functions as a molecular switch between apoptotic and necrotic modes of death receptor-induced cell death.