Biomarker analysis beyond angiogenesis: RAS/RAF mutation status, tumour sidedness, and second-line ramucirumab efficacy in patients with metastatic colorectal carcinoma from RAISE-a global phase III study.

Background: : Second-line treatment with ramucirumab+FOLFIRI improved overall survival (OS) versus placebo+FOLFIRI for patients with metastatic colorectal carcinoma (CRC) [hazard ratio (HR)=0.84, 95% CI 0.73-0.98, P = 0.022]. Post hoc analyses of RAISE patient data examined the association of RAS/RAF mutation status and the anatomical location of the primary CRC tumour (left versus right) with efficacy parameters. Patients and methods: Patient tumour tissue was classified as BRAF mutant, KRAS/NRAS (RAS) mutant, or RAS/BRAF wild-type. Left-CRC was defined as the splenic flexure, descending and sigmoid colon, and rectum; right-CRC included transverse, ascending colon, and cecum. Results: RAS/RAF mutation status was available for 85% of patients (912/1072) and primary tumour location was known for 94.4% of patients (1012/1072). A favourable and comparable ramucirumab treatment effect was observed for patients with RAS mutations (OS HR = 0.86, 95% CI 0.71-1.04) and patients with RAS/BRAF wild-type tumours (OS HR = 0.86, 95% CI 0.64-1.14). Among the 41 patients with BRAF-mutated tumours, the ramucirumab benefit was more notable (OS HR = 0.54, 95% CI 0.25-1.13), although, as with the other genetic sub-group analyses, differences were not statistically significant. Progression-free survival (PFS) data followed the same trend. Treatment-by-mutation status interaction tests (OS P = 0.523, PFS P = 0.655) indicated that the ramucirumab benefit was not statistically different among the mutation sub-groups, although the small sample size of the BRAF group limited the analysis. Addition of ramucirumab to FOLFIRI improved left-CRC median OS by 2.5 month over placebo (HR = 0.81, 95% CI 0.68-0.97); median OS for ramucirumab-treated patients with right-CRC was 1.1 month over placebo (HR = 0.97, 95% CI 0.75-1.26). The treatment-by-sub-group interaction was not statistically significant for tumour sidedness (P = 0.276). Conclusions: In the RAISE study, the addition of ramucirumab to FOLFIRI improved patient outcomes, regardless of RAS/RAF mutation status, and tumour sidedness. Ramucirumab treatment provided a numerically substantial benefit in BRAF-mutated tumours, although the P-values were not statistically significant. ClinicalTrials.gov number: NCT01183780.

Analysis of angiogenesis biomarkers for ramucirumab efficacy in patients with metastatic colorectal cancer from RAISE, a global, randomized, double-blind, phase III study.

Background: The phase III RAISE trial (NCT01183780) demonstrated that the vascular endothelial growth factor (VEGF) receptor (VEGFR)-2 binding monoclonal antibody ramucirumab plus 5-fluororuracil, leucovorin, and irinotecan (FOLFIRI) significantly improved overall survival (OS) and progression-free survival (PFS) compared with placebo + FOLFIRI as second-line metastatic colorectal cancer (mCRC) treatment. To identify patients who benefit the most from VEGFR-2 blockade, the RAISE trial design included a prospective and comprehensive biomarker program that assessed the association of biomarkers with ramucirumab efficacy outcomes. Patients and methods: Plasma and tumor tissue collection was mandatory. Overall, 1072 patients were randomized 1 : 1 to the addition of ramucirumab or placebo to FOLFIRI chemotherapy. Patients were then randomized 1 : 2, for the biomarker program, to marker exploratory (ME) and marker confirmatory (MC) groups. Analyses were carried out using exploratory assays to assess the correlations of baseline marker levels [VEGF-C, VEGF-D, sVEGFR-1, sVEGFR-2, sVEGFR-3 (plasma), and VEGFR-2 (tumor tissue)] with clinical outcomes. Cox regression analyses were carried out for each candidate biomarker with stratification factor adjustment. Results: Biomarker results were available from >80% (n = 894) of patients. Analysis of the ME subset determined a VEGF-D level of 115 pg/ml was appropriate for high/low subgroup analyses. Evaluation of the combined ME + MC populations found that the median OS in the ramucirumab + FOLFIRI arm compared with placebo + FOLFIRI showed an improvement of 2.4 months in the high VEGF-D subgroup [13.9 months (95% CI 12.5-15.6) versus 11.5 months (95% CI 10.1-12.4), respectively], and a decrease of 0.5 month in the low VEGF-D subgroup [12.6 months (95% CI 10.7-14.0) versus 13.1 months (95% CI 11.8-17.0), respectively]. PFS results were consistent with OS. No trends were evident with the other antiangiogenic candidate biomarkers. Conclusions: The RAISE biomarker program identified VEGF-D as a potential predictive biomarker for ramucirumab efficacy in second-line mCRC. Development of an assay appropriate for testing in clinical practice is currently ongoing. Clinical trials registration: NCT01183780.

Correlation of EGFR-expression with safety and efficacy outcomes in SQUIRE: a randomized, multicenter, open-label, phase III study of gemcitabine-cisplatin plus necitumumab versus gemcitabine-cisplatin alone in the first-line treatment of patients with stage IV squamous non-small-cell lung cancer.

BACKGROUND: SQUIRE demonstrated addition of necitumumab to gemcitabine and cisplatin significantly improved survival in patients with stage IV sq-NSCLC. Here, we report additional outcomes for the subpopulation of patients with tumor epidermal growth factor receptor (EGFR) protein expression. PATIENTS AND METHODS: Patients with pathologically confirmed stage IV sq-NSCLC were randomized 1:1 to receive a maximum of six 3-week cycles of gemcitabine (1250 mg/m(2) i.v., days 1 and 8) and cisplatin (75 mg/m(2) i.v., day 1) chemotherapy with or without necitumumab (800 mg i.v., days 1 and 8). Patients in the chemotherapy plus necitumumab group with no progression continued on necitumumab alone until disease progression or intolerable toxicity. SQUIRE included mandatory tissue collection. EGFR protein expression was detected by immunohistochemistry (IHC) in a central laboratory. Exploratory analyses were pre-specified for patients with EGFR protein expressing (EGFR > 0) and non-expressing (EGFR = 0) tumors. RESULTS: A total of 982 patients [90% of intention-to-treat (ITT)] had evaluable IHC results. The large majority of these patients (95%) had tumor samples expressing EGFR protein; only 5% had tumors without detectable EGFR protein. Overall survival (OS) for EGFR > 0 patients was significantly longer in the necitumumab plus gemcitabine-cisplatin group than in the gemcitabine-cisplatin group {stratified hazard ratio (HR) 0.79 [95% confidence interval (CI) 0.69, 0.92; P = 0.002]; median 11.7 months (95% CI 10.7, 12.9) versus 10.0 months (8.9, 11.4)}. Additionally, an OS benefit was seen in all pre-specified subgroups in EGFR > 0 patients. However, OS HR for EGFR = 0 was 1.52. Adverse events of interest with the largest difference between treatment groups in EGFR > 0 patients (Grade ≥3) were hypomagnesemia (10% versus <1%) and skin rash (6% versus <1%). CONCLUSIONS: In line with SQUIRE ITT, addition of necitumumab to gemcitabine-cisplatin significantly prolonged OS and was generally well tolerated in the subpopulation of patients with EGFR-expressing advanced sq-NSCLC. The benefit from addition of necitumumab to chemotherapy was not apparent in this analysis for the small subgroup of patients with non-EGFR-expressing tumors. CLINICAL TRIAL: NCT00981058.

Biomarker analysis in a phase III study of pemetrexed-carboplatin versus etoposide-carboplatin in chemonaive patients with extensive-stage small-cell lung cancer.

BACKGROUND: Clinical results of a randomized phase III trial comparing pemetrexed-carboplatin (PC) with etoposide-carboplatin (EC) in chemonaive patients with extensive-stage disease small-cell lung cancer (ED-SCLC) resulted in trial closure for futility; biomarker analyses using immunohistochemistry (IHC) and single-nucleotide polymorphisms (SNPs) are described herein. PATIENTS AND METHODS: Thymidylate synthase (TS), excision repair cross complementing-1 (ERCC1), glycinamide ribonucleotide formyltransferase (GARFT), and folylpolyglutamate synthetase (FPGS) were investigated using IHC (n=395). SNPs were genotyped for TS, FPGS, γ-glutamyl hydrolase (GGH), methylenetetrahydrofolate reductase (MTHFR), folate receptor-α FR-α, and solute carrier 19A1 (SLC19A1; n=611). RESULTS: None of the IHC biomarkers (folate pathway or ERCC1) were found to be predictive or prognostic in this setting. rs2838952 (adjacent to SLC19A1) had significant treatment-independent association with overall survival (OS; hazard ratio 0.590, P=0.01). Nine GGH-associated SNPs interacted with rs3788205 (SLC19A1) for OS on the PC arm. rs12379987 (FPGS) interacted with treatment for OS (interaction P=0.036). CONCLUSION: Potential ERCC1 and folate pathway IHC biomarkers failed to predict outcome in either study arm in ED-SCLC. SNPs in regions including FPGS and SLC19A1 and interacting SNPs in GGH and SLC19A1 were associated with differences in OS; however, none of these SNPs predicted for greater survival with PC over EC.

Biomarker analyses of second-line ramucirumab in patients with advanced gastric cancer from RAINBOW, a global, randomized, double-blind, phase 3 study.

BACKGROUND: The RAINBOW trial showed that second-line ramucirumab with paclitaxel prolongs overall survival (OS) and progression-free survival (PFS) compared with placebo plus paclitaxel for treatment of advanced gastric/gastroesophageal junction cancer. Plasma samples were collected from patients during the trial and tested to identify predictive and prognostic biomarkers. PATIENTS AND METHODS: Circulating factors in plasma samples from mutually exclusive subsets of RAINBOW patients were assayed using: Intertek assays (24 markers, 380 samples, 57% of patients) and Lilly-developed assay (LDA) platform (5 markers, 257 samples, 39% of patients). Time-trend plots were generated for each marker from the Intertek assays. Baseline patient data were dichotomized into low- and high-marker subgroups. Markers were analyzed for predictive effects using interaction models and for prognostic effects using main-effects models. RESULTS: The Intertek and LDA populations were representative of the full trial population. Plasma levels of VEGF-D and PlGF increased from baseline levels during treatment, then declined after treatment discontinued. Angiopoietin-2 exhibited a decrease during treatment, then increased after treatment discontinuation. No clear time trend was evident with the other markers. Analyses of baseline biomarker expression and its relationship with efficacy variables found no biomarker was predictive for efficacy outcomes, including VEGF-D. However, CRP, HGF, ICAM-3, IL-8, SAA, and VCAM-1 were identified as potential prognostic markers with low baseline levels corresponding to longer OS and PFS. CONCLUSIONS: Pharmacodynamic and prognostic relationships were found from the exploratory biomarker analyses in RAINBOW; however, no predictive markers for ramucirumab in gastric cancer were identified in this trial.

The BIR motifs mediate dominant interference and oligomerization of inhibitor of apoptosis Op-IAP.

The defining structural motif of the inhibitor of apoptosis (iap) protein family is the BIR (baculovirus iap repeat), a highly conserved zinc coordination domain of approximately 70 residues. Although the BIR is required for inhibitor-of-apoptosis (IAP) function, including caspase inhibition, its molecular role in antiapoptotic activity in vivo is unknown. To define the function of the BIRs, we investigated the activity of these structural motifs within Op-IAP, an efficient, virus-derived IAP. We report here that Op-IAP(1-216), a loss-of-function truncation which contains two BIRs but lacks the C-terminal RING motif, potently interfered with Op-IAP's capacity to block apoptosis induced by diverse stimuli. In contrast, Op-IAP(1-216) had no effect on apoptotic suppression by caspase inhibitor P35. Consistent with a mechanism of dominant inhibition that involves direct interaction between Op-IAP(1-216) and full-length Op-IAP, both proteins formed an immunoprecipitable complex in vivo. Op-IAP also self-associated. In contrast, the RING motif-containing truncation Op-IAP(183-268) failed to interact with or interfere with Op-IAP function. Substitution of conserved residues within BIR 2 caused loss of dominant inhibition by Op-IAP(1-216) and coincided with loss of interaction with Op-IAP. Thus, residues encompassing the BIRs mediate dominant inhibition and oligomerization of Op-IAP. Consistent with dominant interference by interaction with an endogenous cellular IAP, Op-IAP(1-216) also lowered the survival threshold of cultured insect cells. Taken together, these data suggest a new model wherein the antiapoptotic function of IAP requires homo-oligomerization, which in turn mediates specific interactions with cellular apoptotic effectors.

Many genomic regions are required for normal embryonic programmed cell death in Caenorhabditis elegans.

To identify genes involved in programmed cell death (PCD) in Caenorhabditis elegans, we screened a comprehensive set of chromosomal deficiencies for alterations in the pattern of PCD throughout embryonic development. From a set of 58 deficiencies, which collectively remove approximately 74% of the genome, four distinct classes were identified. In class I (20 deficiencies), no significant deviation from wild type in the temporal pattern of cell corpses was observed, indicating that much of the genome does not contain zygotic genes that perform conspicuous roles in embryonic PCD. The class II deficiencies (16 deficiencies defining at least 11 distinct genomic regions) led to no or fewer-than-normal cell corpses. Some of these cause premature cell division arrest, probably explaining the diminution in cell corpse number; however, others have little effect on cell proliferation, indicating that the reduced cell corpse number is not a direct result of premature embryonic arrest. In class III (18 deficiencies defining at least 16 unique regions), an excess of cell corpses was observed. The developmental stage at which the extra corpses were observed varied among the class III deficiencies, suggesting the existence of genes that perform temporal-specific functions in PCD. The four deficiencies in class IV (defining at least three unique regions), showed unusually large corpses that were, in some cases, attributable to extremely premature arrest in cell division without a concomitant block in PCD. Deficiencies in this last class suggest that the cell death program does not require normal embryonic cell proliferation to be activated and suggest that while some genes required for cell division might also be required for cell death, others are not. Most of the regions identified by these deficiencies do not contain previously identified zygotic cell death genes. There are, therefore, a substantial number of as yet unidentified genes required for normal PCD in C. elegans.

Aging and accumulation of microdamage in canine bone.

Fractures associated with minimal trauma are common in aged human beings. However, bone safety margins are better preserved in aged dogs, which are rarely affected with minimal trauma fractures. Although the hierarchical architecture of canine and human compact bone is similar, the precise reasons for this species difference are unclear. Cyclic loading of bone during normal daily activity leads to the formation of microcracks within the tissue matrix of compact bone. Using a standard bulk-staining technique with basic fuchsin, we examined calcified transverse sections of the mid-diaphysis of the canine humerus from dogs of varying ages. We found that the amount of microdamage and porosity increased exponentially with aging, although the increases were relatively small, compared with human bone. Gender (female, ovariohysterectomized female, male, castrated male) did not have a significant effect on the amount of microdamage or porosity in bone. Alterations to the local material properties of bone tissue, or alterations to the local tissue repair responses, may play a role in the accumulation of microdamage in bone with aging. Determination of osteocyte lacunar density (number of osteocyte lacunae per bone area) and activation frequency (number of actively remodeling osteons per bone area per year) indicated that these variables declined exponentially with aging. There also was a trend for bone from dogs with low osteocyte lacunar density to have a higher microcrack density, but not higher porosity. Furthermore, bones with a high activation frequency did not accumulate microcracks or porosity. Taken together, these data suggest that, in canine bone, although a certain minimum number of osteocytes may be essential for an operational network that forms part of the signaling pathways that orchestrate repair of bone microdamage, increases in porosity with aging may not be directly associated with impaired function of the osteocyte network within bone.

dad-1, an endogenous programmed cell death suppressor in Caenorhabditis elegans and vertebrates.

Programmed cell death (apoptosis) is a normally occurring process used to eliminate unnecessary or potentially harmful cells in multicellular organisms. Recent studies demonstrate that the molecular control of this process is conserved phylogenetically in animals. The dad-1 gene, which encodes a novel 113 amino acid protein, was originally identified in a mutant hamster cell line (tsBN7) that undergoes apoptosis at restrictive temperature. We have identified a dad-1 homologue in Caenorhabditis elegans (Ce-dad-1) whose predicted product is > 60% identical to vertebrate DAD-1. A search of the sequence databases indicated that DAD-1-like proteins are also expressed in two plant species. Expression of either human dad-1 or Ce-dad-1 under control of a C.elegans heat-shock-inducible promoter resulted in a reduction in the number of programmed cell death corpses visible in C.elegans embryos. Extra surviving cells were present in these animals, indicating that both the human and C.elegans dad-1 genes can suppress developmentally programmed cell death. Ce-dad-1 was found to rescue mutant tsBN7 hamster cells from apoptotic death as efficiently as the vertebrate genes. These results suggest that dad-1, which is necessary for cell survival in a mammalian cell line, is sufficient to suppress some programmed cell death in C.elegans.

Baculovirus inhibitor of apoptosis functions at or upstream of the apoptotic suppressor P35 to prevent programmed cell death.

Members of the inhibitor of apoptosis (iap) gene family prevent programmed cell death induced by multiple signals in diverse organisms, suggesting that they act at a conserved step in the apoptotic pathway. To investigate the molecular mechanism of iap function, we expressed epitope-tagged Op-iap, the prototype viral iap from Orgyia pseudotsugata nuclear polyhedrosis virus, by using novel baculovirus recombinants and stably transfected insect cell lines. Epitope-tagged Op-iap blocked both virus- and UV radiation-induced apoptosis. With or without apoptotic stimuli, Op-IAP protein (31 kDa) cofractionated with cellular membranes and the cytosol, suggesting a cytoplasmic site of action. To identify the step(s) at which Op-iap blocks apoptosis, we monitored the effect of Op-iap expression on in vivo activation of the insect CED-3/ICE death proteases (caspases). Op-iap prevented in vivo caspase-mediated cleavage of the baculovirus substrate inhibitor P35 and blocked caspase activity upon viral infection or UV irradiation. However, unlike the stoichiometric inhibitor P35, Op-IAP failed to affect activated caspase as determined by in vitro protease assays. These findings provide the first biochemical evidence that Op-iap blocks activation of the host caspase or inhibits its activity by a mechanism distinct from P35. Moreover, as suggested by the capacity of Op-iap to block apoptosis induced by diverse signals, including virus infection and UV radiation, iap functions at a central point at or upstream from steps involving the death proteases.

Kinetics and inhibition of lipid exchange catalyzed by plasma cholesteryl ester transfer protein (lipid transfer protein).

The cholesteryl ester transfer protein-catalyzed cholesteryl ester transfer is inhibited by two compounds identified by a large-scale screening of cholesterol backbone-containing molecules. Kinetic analysis shows that U-95,594, an amino steroid, inhibits competitively the cholesteryl ester transfer protein-catalyzed transfer of both cholesteryl esters and triglycerides, as well from high-density lipoproteins as from synthetic microemulsions. In contrast, U-617, an organomercurial derivative of cholesterol, inhibits competitively the transfer of cholesteryl ester from either donor but is without any effect on triglyceride transfer. In addition to the rapid, competitive inhibition of cholesteryl ester transfer, U-617 also slowly and reversibly reacts with cholesteryl ester transfer protein to produce an additional 10-fold decrease in cholesteryl ester transfer activity but, again, without effect on triglyceride transfer.