RESUMEN
BACKGROUND: Patients with advanced squamous-cell non-small-cell lung cancer (NSCLC) who have disease progression during or after first-line chemotherapy have limited treatment options. This randomized, open-label, international, phase 3 study evaluated the efficacy and safety of nivolumab, a fully human IgG4 programmed death 1 (PD-1) immune-checkpoint-inhibitor antibody, as compared with docetaxel in this patient population. METHODS: We randomly assigned 272 patients to receive nivolumab, at a dose of 3 mg per kilogram of body weight every 2 weeks, or docetaxel, at a dose of 75 mg per square meter of body-surface area every 3 weeks. The primary end point was overall survival. RESULTS: The median overall survival was 9.2 months (95% confidence interval [CI], 7.3 to 13.3) with nivolumab versus 6.0 months (95% CI, 5.1 to 7.3) with docetaxel. The risk of death was 41% lower with nivolumab than with docetaxel (hazard ratio, 0.59; 95% CI, 0.44 to 0.79; P<0.001). At 1 year, the overall survival rate was 42% (95% CI, 34 to 50) with nivolumab versus 24% (95% CI, 17 to 31) with docetaxel. The response rate was 20% with nivolumab versus 9% with docetaxel (P=0.008). The median progression-free survival was 3.5 months with nivolumab versus 2.8 months with docetaxel (hazard ratio for death or disease progression, 0.62; 95% CI, 0.47 to 0.81; P<0.001). The expression of the PD-1 ligand (PD-L1) was neither prognostic nor predictive of benefit. Treatment-related adverse events of grade 3 or 4 were reported in 7% of the patients in the nivolumab group as compared with 55% of those in the docetaxel group. CONCLUSIONS: Among patients with advanced, previously treated squamous-cell NSCLC, overall survival, response rate, and progression-free survival were significantly better with nivolumab than with docetaxel, regardless of PD-L1 expression level. (Funded by Bristol-Myers Squibb; CheckMate 017 ClinicalTrials.gov number, NCT01642004.).
Asunto(s)
Anticuerpos Monoclonales/uso terapéutico , Antineoplásicos/uso terapéutico , Antígeno B7-H1/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Neoplasias Pulmonares/tratamiento farmacológico , Taxoides/uso terapéutico , Adulto , Anciano , Anticuerpos Monoclonales/efectos adversos , Antineoplásicos/efectos adversos , Carcinoma de Pulmón de Células no Pequeñas/mortalidad , Carcinoma de Células Escamosas/tratamiento farmacológico , Carcinoma de Células Escamosas/mortalidad , Docetaxel , Femenino , Humanos , Inmunoglobulina G , Neoplasias Pulmonares/mortalidad , Masculino , Persona de Mediana Edad , Nivolumab , Receptor de Muerte Celular Programada 1/inmunología , Análisis de Supervivencia , Taxoides/efectos adversosRESUMEN
BACKGROUND: Nivolumab, a fully human IgG4 programmed death 1 (PD-1) immune-checkpoint-inhibitor antibody, disrupts PD-1-mediated signaling and may restore antitumor immunity. METHODS: In this randomized, open-label, international phase 3 study, we assigned patients with nonsquamous non-small-cell lung cancer (NSCLC) that had progressed during or after platinum-based doublet chemotherapy to receive nivolumab at a dose of 3 mg per kilogram of body weight every 2 weeks or docetaxel at a dose of 75 mg per square meter of body-surface area every 3 weeks. The primary end point was overall survival. RESULTS: Overall survival was longer with nivolumab than with docetaxel. The median overall survival was 12.2 months (95% confidence interval [CI], 9.7 to 15.0) among 292 patients in the nivolumab group and 9.4 months (95% CI, 8.1 to 10.7) among 290 patients in the docetaxel group (hazard ratio for death, 0.73; 96% CI, 0.59 to 0.89; P=0.002). At 1 year, the overall survival rate was 51% (95% CI, 45 to 56) with nivolumab versus 39% (95% CI, 33 to 45) with docetaxel. With additional follow-up, the overall survival rate at 18 months was 39% (95% CI, 34 to 45) with nivolumab versus 23% (95% CI, 19 to 28) with docetaxel. The response rate was 19% with nivolumab versus 12% with docetaxel (P=0.02). Although progression-free survival did not favor nivolumab over docetaxel (median, 2.3 months and 4.2 months, respectively), the rate of progression-free survival at 1 year was higher with nivolumab than with docetaxel (19% and 8%, respectively). Nivolumab was associated with even greater efficacy than docetaxel across all end points in subgroups defined according to prespecified levels of tumor-membrane expression (≥1%, ≥5%, and ≥10%) of the PD-1 ligand. Treatment-related adverse events of grade 3 or 4 were reported in 10% of the patients in the nivolumab group, as compared with 54% of those in the docetaxel group. CONCLUSIONS: Among patients with advanced nonsquamous NSCLC that had progressed during or after platinum-based chemotherapy, overall survival was longer with nivolumab than with docetaxel. (Funded by Bristol-Myers Squibb; CheckMate 057 ClinicalTrials.gov number, NCT01673867.).
Asunto(s)
Anticuerpos Monoclonales/uso terapéutico , Antineoplásicos/uso terapéutico , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Neoplasias Pulmonares/tratamiento farmacológico , Taxoides/uso terapéutico , Anciano , Anticuerpos Monoclonales/efectos adversos , Antineoplásicos/efectos adversos , Antígeno B7-H1/antagonistas & inhibidores , Antígeno B7-H1/inmunología , Antígeno B7-H1/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/mortalidad , Docetaxel , Femenino , Humanos , Neoplasias Pulmonares/mortalidad , Masculino , Persona de Mediana Edad , Nivolumab , Análisis de Supervivencia , Taxoides/efectos adversosRESUMEN
BACKGROUND: Immune checkpoint inhibitors are effective cancer treatments, but molecular determinants of clinical benefit are unknown. Ipilimumab and tremelimumab are antibodies against cytotoxic T-lymphocyte antigen 4 (CTLA-4). Anti-CTLA-4 treatment prolongs overall survival in patients with melanoma. CTLA-4 blockade activates T cells and enables them to destroy tumor cells. METHODS: We obtained tumor tissue from patients with melanoma who were treated with ipilimumab or tremelimumab. Whole-exome sequencing was performed on tumors and matched blood samples. Somatic mutations and candidate neoantigens generated from these mutations were characterized. Neoantigen peptides were tested for the ability to activate lymphocytes from ipilimumab-treated patients. RESULTS: Malignant melanoma exomes from 64 patients treated with CTLA-4 blockade were characterized with the use of massively parallel sequencing. A discovery set consisted of 11 patients who derived a long-term clinical benefit and 14 patients who derived a minimal benefit or no benefit. Mutational load was associated with the degree of clinical benefit (P=0.01) but alone was not sufficient to predict benefit. Using genomewide somatic neoepitope analysis and patient-specific HLA typing, we identified candidate tumor neoantigens for each patient. We elucidated a neoantigen landscape that is specifically present in tumors with a strong response to CTLA-4 blockade. We validated this signature in a second set of 39 patients with melanoma who were treated with anti-CTLA-4 antibodies. Predicted neoantigens activated T cells from the patients treated with ipilimumab. CONCLUSIONS: These findings define a genetic basis for benefit from CTLA-4 blockade in melanoma and provide a rationale for examining exomes of patients for whom anti-CTLA-4 agents are being considered. (Funded by the Frederick Adler Fund and others.).
Asunto(s)
Anticuerpos Monoclonales/uso terapéutico , Antineoplásicos/uso terapéutico , Antígeno CTLA-4/antagonistas & inhibidores , Melanoma/genética , Neoplasias Cutáneas/genética , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Monoclonales Humanizados , Antígeno CTLA-4/inmunología , Exoma , Femenino , Secuenciación de Nucleótidos de Alto Rendimiento , Prueba de Histocompatibilidad , Humanos , Ipilimumab , Masculino , Melanoma/tratamiento farmacológico , Melanoma/inmunología , Melanoma/secundario , Persona de Mediana Edad , Mutación , Neoplasias Cutáneas/tratamiento farmacológico , Neoplasias Cutáneas/inmunologíaRESUMEN
BACKGROUND: Treatments for small-cell lung cancer (SCLC) after failure of platinum-based chemotherapy are limited. We assessed safety and activity of nivolumab and nivolumab plus ipilimumab in patients with SCLC who progressed after one or more previous regimens. METHODS: The SCLC cohort of this phase 1/2 multicentre, multi-arm, open-label trial was conducted at 23 sites (academic centres and hospitals) in six countries. Eligible patients were 18 years of age or older, had limited-stage or extensive-stage SCLC, and had disease progression after at least one previous platinum-containing regimen. Patients received nivolumab (3 mg/kg bodyweight intravenously) every 2 weeks (given until disease progression or unacceptable toxicity), or nivolumab plus ipilimumab (1 mg/kg plus 1 mg/kg, 1 mg/kg plus 3 mg/kg, or 3 mg/kg plus 1 mg/kg, intravenously) every 3 weeks for four cycles, followed by nivolumab 3 mg/kg every 2 weeks. Patients were either assigned to nivolumab monotherapy or assessed in a dose-escalating safety phase for the nivolumab/ipilimumab combination beginning at nivolumab 1 mg/kg plus ipilimumab 1 mg/kg. Depending on tolerability, patients were then assigned to nivolumab 1 mg/kg plus ipilimumab 3 mg/kg or nivolumab 3 mg/kg plus ipilimumab 1 mg/kg. The primary endpoint was objective response by investigator assessment. All analyses included patients who were enrolled at least 90 days before database lock. This trial is ongoing; here, we report an interim analysis of the SCLC cohort. This study is registered with ClinicalTrials.gov, number NCT01928394. FINDINGS: Between Nov 18, 2013, and July 28, 2015, 216 patients were enrolled and treated (98 with nivolumab 3 mg/kg, three with nivolumab 1 mg/kg plus ipilimumab 1 mg/kg, 61 with nivolumab 1 mg/kg plus ipilimumab 3 mg/kg, and 54 with nivolumab 3 mg/kg plus ipilimumab 1 mg/kg). At database lock on Nov 6, 2015, median follow-up for patients continuing in the study (including those who had died or discontinued treatment) was 198·5 days (IQR 163·0-464·0) for nivolumab 3 mg/kg, 302 days (IQR not calculable) for nivolumab 1 mg/kg plus ipilimumab 1 mg/kg, 361·0 days (273·0-470·0) for nivolumab 1 mg/kg plus ipilimumab 3 mg/kg, and 260·5 days (248·0-288·0) for nivolumab 3 mg/kg plus ipilimumab 1 mg/kg. An objective response was achieved in ten (10%) of 98 patients receiving nivolumab 3 mg/kg, one (33%) of three patients receiving nivolumab 1 mg/kg plus ipilimumab 1 mg/kg, 14 (23%) of 61 receiving nivolumab 1 mg/kg plus ipilimumab 3 mg/kg, and ten (19%) of 54 receiving nivolumab 3 mg/kg plus ipilimumab 1 mg/kg. Grade 3 or 4 treatment-related adverse events occurred in 13 (13%) patients in the nivolumab 3 mg/kg cohort, 18 (30%) in the nivolumab 1 mg/kg plus ipilimumab 3 mg/kg cohort, and ten (19%) in the nivolumab 3 mg/kg plus ipilimumab 1 mg/kg cohort; the most commonly reported grade 3 or 4 treatment-related adverse events were increased lipase (none vs 5 [8%] vs none) and diarrhoea (none vs 3 [5%] vs 1 [2%]). No patients in the nivolumab 1 mg/kg plus ipilimumab 1 mg/kg cohort had a grade 3 or 4 treatment-related adverse event. Six (6%) patients in the nivolumab 3 mg/kg group, seven (11%) in the nivolumab 1 mg/kg plus ipilimumab 3 mg/kg group, and four (7%) in the nivolumab 3 mg/kg plus ipilimumab 1 mg/kg group discontinued treatment due to treatment-related adverse events. Two patients who received nivolumab 1 mg/kg plus ipilimumab 3 mg/kg died from treatment-related adverse events (myasthenia gravis and worsening of renal failure), and one patient who received nivolumab 3 mg/kg plus ipilimumab 1 mg/kg died from treatment-related pneumonitis. INTERPRETATION: Nivolumab monotherapy and nivolumab plus ipilimumab showed antitumour activity with durable responses and manageable safety profiles in previously treated patients with SCLC. These data suggest a potential new treatment approach for a population of patients with limited treatment options and support the evaluation of nivolumab and nivolumab plus ipilimumab in phase 3 randomised controlled trials in SCLC. FUNDING: Bristol-Myers Squibb.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias Pulmonares/tratamiento farmacológico , Recurrencia Local de Neoplasia/tratamiento farmacológico , Carcinoma Pulmonar de Células Pequeñas/tratamiento farmacológico , Anciano , Anticuerpos Monoclonales/administración & dosificación , Femenino , Estudios de Seguimiento , Humanos , Ipilimumab , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia/patología , Estadificación de Neoplasias , Nivolumab , Pronóstico , Carcinoma Pulmonar de Células Pequeñas/patología , Tasa de SupervivenciaRESUMEN
BACKGROUND: Patients with squamous non-small-cell lung cancer that is refractory to multiple treatments have poor outcomes. We assessed the activity of nivolumab, a fully human IgG4 PD-1 immune checkpoint inhibitor antibody, for patients with advanced, refractory, squamous non-small-cell lung cancer. METHODS: We did this phase 2, single-arm trial at 27 sites (academic, hospital, and private cancer centres) in France, Germany, Italy, and USA. Patients who had received two or more previous treatments received intravenous nivolumab (3 mg/kg) every 2 weeks until progression or unacceptable toxic effects. The primary endpoint was the proportion of patients with a confirmed objective response as assessed by an independent radiology review committee. We included all treated patients in the analyses. This study is registered with ClinicalTrials.gov, number NCT01721759. FINDINGS: Between Nov 16, 2012, and July 22, 2013, we enrolled and treated 117 patients. 17 (14·5%, 95% CI 8·7-22·2) of 117 patients had an objective response as assessed by an independent radiology review committee. Median time to response was 3·3 months (IQR 2·2-4·8), and median duration of response was not reached (95% CI 8·31-not applicable); 13 (77%) of 17 of responses were ongoing at the time of analysis. 30 (26%) of 117 patients had stable disease (median duration 6·0 months, 95% CI 4·7-10·9). 20 (17%) of 117 patients reported grade 3-4 treatment-related adverse events, including: fatigue (five [4%] of 117 patients), pneumonitis (four [3%]), and diarrhoea (three [3%]). There were two treatment-associated deaths caused by pneumonia and ischaemic stroke that occurred in patients with multiple comorbidities in the setting of progressive disease. INTERPRETATION: Nivolumab has clinically meaningful activity and a manageable safety profile in previously treated patients with advanced, refractory, squamous non-small cell lung cancer. These data support the assessment of nivolumab in randomised, controlled, phase 3 studies of first-line and second-line treatment. FUNDING: Bristol-Myers Squibb.
Asunto(s)
Anticuerpos Monoclonales/uso terapéutico , Antineoplásicos/uso terapéutico , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Neoplasias Pulmonares/tratamiento farmacológico , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Anciano , Anticuerpos Monoclonales/administración & dosificación , Anticuerpos Monoclonales/efectos adversos , Antineoplásicos/administración & dosificación , Antineoplásicos/efectos adversos , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/mortalidad , Carcinoma de Pulmón de Células no Pequeñas/patología , Comorbilidad , Progresión de la Enfermedad , Supervivencia sin Enfermedad , Esquema de Medicación , Europa (Continente) , Femenino , Humanos , Infusiones Intravenosas , Estimación de Kaplan-Meier , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/mortalidad , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Terapia Molecular Dirigida , Nivolumab , Receptor de Muerte Celular Programada 1/metabolismo , Factores de Riesgo , Transducción de Señal/efectos de los fármacos , Factores de Tiempo , Resultado del Tratamiento , Estados UnidosRESUMEN
Reciprocal selective effects between coevolving species are often influenced by interactions with the broader ecological community. Community-level interactions may also influence macroevolutionary patterns of coevolution, such as cospeciation, but this hypothesis has received little attention. We studied two groups of ecologically similar feather lice (Phthiraptera: Ischnocera) that differ in their patterns of association with a single group of hosts. The two groups, "body lice" and "wing lice," are both parasites of pigeons and doves (Columbiformes). Body lice are more host-specific and show greater population genetic structure than wing lice. The macroevolutionary history of body lice also parallels that of their columbiform hosts more closely than does the evolutionary history of wing lice. The closer association of body lice with hosts, compared with wing lice, can be explained if body lice are less capable of switching hosts than wing lice. Wing lice sometimes disperse phoretically on parasitic flies (Diptera: Hippoboscidae), but body lice seldom engage in this behavior. We tested the hypothesis that wing lice switch host species more often than body lice, and that the difference is governed by phoresis. Our results show that, where flies are present, wing lice switch to novel host species in sufficient numbers to establish viable populations on the new host. Body lice do not switch hosts, even where flies are present. Thus, differences in the coevolutionary history of wing and body lice can be explained by differences in host-switching, mediated by a member of the broader parasite community.
Asunto(s)
Evolución Biológica , Enfermedades de las Aves/parasitología , Columbidae/parasitología , Phthiraptera/fisiología , Animales , Dípteros/parasitología , Ecosistema , Especificidad del Huésped , Interacciones Huésped-Parásitos , Phthiraptera/clasificación , Especificidad de la EspecieRESUMEN
Pheromone communication is central to the life history of insect parasites. Determining how pheromones affect parasite behavior can provide insights into host-parasite interactions and suggest novel avenues for parasite control. Lice infest thousands of bird and mammal species and feed on the host's feathers or blood. Despite the pervasiveness of lice in wild populations and the costs they exact on livestock and poultry industries, little is known about pheromone communication in this diverse group. Here, we test for pheromone communication in the wing lice (Columbicola columbae) of Rock Doves (Columba livia). Wing lice spend the majority of their lives on bird flight feathers where they hide from host preening by inserting their bodies between coarse feather barbs. To feed, wing lice must migrate to bird body regions where they consume the insulating barbs of contour feathers. We first show that wing lice readily form aggregations on flight feathers. Next, using a Y-tube olfactometer, we demonstrate that wing lice use pheromone communication to move toward groups of nearby conspecifics. This pheromone is likely an aggregation pheromone, as wing lice only produce the pheromone when placed on flight feathers. Finally, we found that when forced to choose between groups of male and female lice, male lice move toward male groups and females toward female groups, suggesting the use of multiple pheromones. Ongoing work aims to determine the chemical identity and function of these pheromones.
Asunto(s)
Anoplura , Enfermedades de las Aves , Ischnocera , Infestaciones por Piojos , Parásitos , Phthiraptera , Animales , Masculino , Femenino , Infestaciones por Piojos/veterinaria , Infestaciones por Piojos/parasitología , Columbidae/parasitología , Enfermedades de las Aves/parasitología , Interacciones Huésped-Parásitos , Comunicación , MamíferosRESUMEN
PURPOSE: In advanced gastric cancer/gastroesophageal junction cancer (GC/GEJC), there is a need to identify biomarkers of response to therapies, such as immune checkpoint inhibitors. PATIENTS AND METHODS: In post hoc exploratory analyses from CheckMate 032 (GC/GEJC cohort), we evaluated associations between nivolumab ± ipilimumab (NIVO ± IPI) efficacy and programmed death ligand 1 (PD-L1) expression, defined by tumor cells (% TC) or combined positive score (CPS; sum of PD-L1-staining TCs + immune cells, divided by total viable TCs, × 100) using the Dako PD-L1 IHC 28-8 pharmDx assay, or inflammatory gene expression. RESULTS: There was a trend toward increased efficacy (objective response and overall survival) when PD-L1 expression was determined by CPS compared with % TC at higher cutoffs of ≥5 and ≥10 in the pooled analysis of all treatment regimens. In this analysis, 19% and 26% of patients with PD-L1-positive tumors at a CPS cutoff of ≥5 and ≥10, respectively, had an objective response compared with 8% and 9% of patients at the equivalent % TC cutoffs. Longer survival was demonstrated in patients with PD-L1-positive (defined by CPS cutoffs of ≥5 and ≥10) versus PD-L1-negative status. Similar results were observed in the NIVO 1 mg/kg + IPI 3 mg/kg subgroup. Multiple inflammatory gene signatures/transcripts, including a signature consisting of four genes (CD274, CD8A, LAG3, and STAT1), showed associations with response to NIVO ± IPI. CONCLUSIONS: This study suggests a greater association of PD-L1 expression by CPS with NIVO ± IPI efficacy compared with % TC PD-L1 expression in patients with GC/GEJC. Inflammatory signatures were also associated with NIVO ± IPI response, warranting further investigation.See related commentary by Moutafi and Rimm, p. 3812.
Asunto(s)
Antineoplásicos Inmunológicos/administración & dosificación , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Antígeno B7-H1/genética , Neoplasias Esofágicas/tratamiento farmacológico , Neoplasias Esofágicas/genética , Unión Esofagogástrica , Inflamación/genética , Ipilimumab/administración & dosificación , Nivolumab/administración & dosificación , Neoplasias Gástricas/tratamiento farmacológico , Neoplasias Gástricas/genética , Anciano , Neoplasias Esofágicas/complicaciones , Femenino , Humanos , Inflamación/complicaciones , Masculino , Persona de Mediana Edad , Neoplasias Gástricas/complicaciones , Resultado del TratamientoRESUMEN
(3R,4R)-4-Amino-1-((4-((3-methoxyphenyl)amino)pyrrolo[2,1-f][1,2,4]triazin-5-yl)methyl)-3-piperidinol (BMS-690514), an oral selective inhibitor of human epidermal growth factor receptors 1 (or epidermal growth factor receptor), 2, and 4, and vascular endothelial growth factor receptors 1, 2, and 3, is being developed as a treatment for patients with non-small-cell lung cancer and metastatic breast cancer. The disposition of [(14)C]BMS-690514 was investigated in nine healthy male subjects (group 1, n = 6; group 2, n = 3) after oral administration of a 200-mg dose. Urine, feces, and plasma were collected from all subjects for up to 12 days postdose. In group 2 subjects, bile was collected from 3 to 8 h postdose. Across groups, approximately 50 and 34% of administered radioactivity was recovered in the feces and urine, respectively. An additional 16% was recovered in the bile of group 2 subjects. Less than 28% of the dose was recovered as parent drug in the combined excreta, suggesting that BMS-690514 was highly metabolized. BMS-690514 was rapidly absorbed (median time of maximum observed concentration 0.5 h) with the absorbed fraction estimated to be approximately 50 to 68%. BMS-690514 represented ≤7.9% of the area under the concentration-time curve from time 0 extrapolated to infinite time of plasma radioactivity, indicating that the majority of the circulating radioactivity was from metabolites. BMS-690514 was metabolized via multiple oxidation reactions and direct glucuronidation. Circulating metabolites included a hydroxylated rearrangement product (M1), a direct ether glucuronide (M6), and multiple secondary glucuronide conjugates. None of these metabolites is expected to contribute to the pharmacology of BMS-690514. In summary, BMS-690514 was well absorbed and extensively metabolized via multiple metabolic pathways in humans, with excretion of drug-related radioactivity in both bile and urine.
Asunto(s)
Antineoplásicos/farmacocinética , Piperidinas/farmacocinética , Pirroles/farmacocinética , Proteínas Tirosina Quinasas Receptoras/antagonistas & inhibidores , Triazinas/farmacocinética , Absorción , Administración Oral , Adolescente , Adulto , Antineoplásicos/sangre , Antineoplásicos/metabolismo , Antineoplásicos/farmacología , Antineoplásicos/orina , Bilis/química , Biotransformación , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Citocromo P-450 CYP2D6/genética , Citocromo P-450 CYP2D6/metabolismo , Relación Dosis-Respuesta a Droga , Heces/química , Glucurónidos/metabolismo , Glucuronosiltransferasa/genética , Glucuronosiltransferasa/metabolismo , Humanos , Hidroxilación , Masculino , Oxidación-Reducción , Piperidinas/sangre , Piperidinas/metabolismo , Piperidinas/farmacología , Piperidinas/orina , Polimorfismo de Nucleótido Simple , Proteínas Quinasas/metabolismo , Pirroles/sangre , Pirroles/metabolismo , Pirroles/farmacología , Pirroles/orina , Distribución Tisular , Triazinas/sangre , Triazinas/metabolismo , Triazinas/farmacología , Triazinas/orina , Adulto JovenRESUMEN
DNA-binding transcriptional regulators interpret the genome's regulatory code by binding to specific sequences to induce or repress gene expression. Comparative genomics has recently been used to identify potential cis-regulatory sequences within the yeast genome on the basis of phylogenetic conservation, but this information alone does not reveal if or when transcriptional regulators occupy these binding sites. We have constructed an initial map of yeast's transcriptional regulatory code by identifying the sequence elements that are bound by regulators under various conditions and that are conserved among Saccharomyces species. The organization of regulatory elements in promoters and the environment-dependent use of these elements by regulators are discussed. We find that environment-specific use of regulatory elements predicts mechanistic models for the function of a large population of yeast's transcriptional regulators.
Asunto(s)
Genoma Fúngico , Elementos de Respuesta/genética , Saccharomyces/genética , Factores de Transcripción/metabolismo , Transcripción Genética/genética , Secuencia de Bases , Sitios de Unión , Secuencia Conservada/genética , Células Eucariotas/metabolismo , Regiones Promotoras Genéticas/genética , Saccharomyces/clasificación , Especificidad por SustratoRESUMEN
Thermal cues are widely used by ectoparasites to find and exploit hosts. Recently, the wing louse Columbicola columbae (Phthiraptera: Ischnocera) was shown to use thermo-orientation when migrating between host microhabitats. Here, we study the control systems governing thermo-orientation by motion tracking wing lice on spatial and temporal heat gradients. As previously demonstrated, lice placed on spatial heat gradients successfully located nearby heat targets. Unilateral antennectomies were then used to remove spatial aspects of the thermal cue. These lice were still capable of locating heat targets, suggesting their response relied on tracking changes in the cue over time (idiothetic control). Course control was accomplished via angular corrections after louse body-angles deviated from the heat target. Louse behavior on temporal heat gradients provided additional evidence for idiothetic control- lice altered turn size and velocity after temperatures uniformly shifted without any spatial reference. We also show that lice are likely capable of responding to spatial aspects of the cue, consistent with allothetic control. On the spatial heat gradient, lice with two antennae were more efficient at locating heat targets as compared to those with unilateral antennectomies. Additionally, when traveling along temperature isoclines (where lice can detect spatial but not temporal aspects of the cue), lice with two antennae consistently turned towards the heat target, while those with unilateral antennectomies showed no preference. In all, we find evidence that lice can use both idiothetic and allothetic control during thermo-orientation, and likely integrate information from these two systems to guide movements on hosts.
Asunto(s)
Anoplura/fisiología , Señales (Psicología) , Plumas/parasitología , Interacciones Huésped-Parásitos , Calor , Animales , Enfermedades de las Aves/parasitología , Femenino , Infestaciones por Piojos/parasitología , Infestaciones por Piojos/veterinaria , Masculino , Orientación/fisiologíaRESUMEN
Parasites are incredibly diverse. An important factor in the evolution of this diversity is the fact that many parasite species are restricted to 1, or just a few, host species. In addition, some parasites exhibit geographic specificity that is nested within their specificity to a particular species of host. The environmental factors that restrict parasites to particular regions within the host's range are poorly understood, and it is often difficult to know whether such patterns of geographic specificity are real, or merely artifacts of uneven host sampling. For over a decade, we sampled communities of ectoparasitic lice (Phthiraptera) from western scrub-jays (Aphelocoma californica) throughout their range in the United States, and found 3 common species of lice. Philopterus crassipes was found throughout the host range, whereas the other 2 species of lice had more restricted distributions. Brueelia deficiens was found only on the woodhouseii host subspecies group, and Myrsidea sp. was found largely on the californica host subspecies group. We suggest that differential tolerance to arid conditions and interspecific competition has led to the restricted geographic distributions of these 2 species of lice.
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Enfermedades de las Aves/parasitología , Infestaciones por Piojos/veterinaria , Passeriformes/parasitología , Phthiraptera/clasificación , Animales , Enfermedades de las Aves/epidemiología , Infestaciones por Piojos/epidemiología , Infestaciones por Piojos/parasitología , Oregon/epidemiología , Prevalencia , Sudoeste de Estados Unidos/epidemiologíaRESUMEN
IMPORTANCE: Nivolumab, a monoclonal antibody that inhibits programmed cell death 1, is approved by the US Food and Drug Administration for treating advanced melanoma, renal cell carcinoma (RCC), non-small cell lung cancer (NSCLC), and other malignancies. Data on long-term survival among patients receiving nivolumab are limited. OBJECTIVES: To analyze long-term overall survival (OS) among patients receiving nivolumab and identify clinical and laboratory measures associated with tumor regression and OS. DESIGN, SETTING, AND PARTICIPANTS: This was a secondary analysis of the phase 1 CA209-003 trial (with expansion cohorts), which was conducted at 13 US medical centers and included 270 patients with advanced melanoma, RCC, or NSCLC who received nivolumab and were enrolled between October 30, 2008, and December 28, 2011. The analyses were either specified in the original protocol or included in subsequent protocol amendments that were implemented between 2008 and 2012. Statistical analysis was performed from October 30, 2008, to November 11, 2016. INTERVENTION: In the CA209-003 trial, patients received nivolumab (0.1-10.0 mg/kg) every 2 weeks in 8-week cycles for up to 96 weeks, unless they developed progressive disease, achieved a complete response, experienced unacceptable toxic effects, or withdrew consent. MAIN OUTCOMES AND MEASURES: Safety and activity of nivolumab; OS was a post hoc end point with a minimum follow-up of 58.3 months. RESULTS: Of 270 patients included in this analysis, 107 (39.6%) had melanoma (72 [67.3%] male; median age, 61 [range, 29-85] years), 34 (12.6%) had RCC (26 [76.5%] male; median age, 58 [range, 35-74] years), and 129 (47.8%) had NSCLC (79 [61.2%] male; median age, 65 [range, 38-85] years). Overall survival curves showed estimated 5-year rates of 34.2% among patients with melanoma, 27.7% among patients with RCC, and 15.6% among patients with NSCLC. In a multivariable analysis, the presence of liver (odds ratio [OR], 0.31; 95% CI, 0.12-0.83; P = .02) or bone metastases (OR, 0.31; 95% CI, 0.10-0.93; P = .04) was independently associated with reduced likelihood of survival at 5 years, whereas an Eastern Cooperative Oncology Group performance status of 0 (OR, 2.74; 95% CI, 1.43-5.27; P = .003) was independently associated with an increased likelihood of 5-year survival. Overall survival was significantly longer among patients with treatment-related AEs of any grade (median, 19.8 months; 95% CI, 13.8-26.9 months) or grade 3 or more (median, 20.3 months; 95% CI, 12.5-44.9 months) compared with those without treatment-related AEs (median, 5.8 months; 95% CI, 4.6-7.8 months) (P < .001 for both comparisons based on hazard ratios). CONCLUSIONS AND RELEVANCE: Nivolumab treatment was associated with long-term survival in a subset of heavily pretreated patients with advanced melanoma, RCC, or NSCLC. Characterizing factors associated with long-term survival may inform treatment approaches and strategies for future clinical trial development. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT00730639.
RESUMEN
Even simple organisms have the ability to respond to internal and external stimuli. This response is carried out by a dynamic network of protein-DNA interactions that allows the specific regulation of genes needed for the response. We have developed a novel computational method that uses an input-output hidden Markov model to model these regulatory networks while taking into account their dynamic nature. Our method works by identifying bifurcation points, places in the time series where the expression of a subset of genes diverges from the rest of the genes. These points are annotated with the transcription factors regulating these transitions resulting in a unified temporal map. Applying our method to study yeast response to stress, we derive dynamic models that are able to recover many of the known aspects of these responses. Predictions made by our method have been experimentally validated leading to new roles for Ino4 and Gcn4 in controlling yeast response to stress. The temporal cascade of factors reveals common pathways and highlights differences between master and secondary factors in the utilization of network motifs and in condition-specific regulation.
Asunto(s)
Biología Computacional/métodos , Regulación Fúngica de la Expresión Génica , Redes Reguladoras de Genes , Cadenas de Markov , Saccharomyces cerevisiae/genética , Algoritmos , Aminoácidos/deficiencia , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico , Análisis por Conglomerados , Simulación por Computador , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Bases de Datos Genéticas , Perfilación de la Expresión Génica , Modelos Genéticos , Distribución Normal , Análisis de Secuencia por Matrices de Oligonucleótidos , Reproducibilidad de los Resultados , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Factores de Tiempo , Transactivadores/genética , Transactivadores/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismoRESUMEN
PURPOSE: Metastatic esophagogastric cancer treatments after failure of second-line chemotherapy are limited. Nivolumab demonstrated superior overall survival (OS) versus placebo in Asian patients with advanced gastric or gastroesophageal junction cancers. We assessed the safety and efficacy of nivolumab and nivolumab plus ipilimumab in Western patients with chemotherapy-refractory esophagogastric cancers. PATIENTS AND METHODS: Patients with locally advanced or metastatic chemotherapy-refractory gastric, esophageal, or gastroesophageal junction cancer from centers in the United States and Europe received nivolumab or nivolumab plus ipilimumab. The primary end point was objective response rate. The association of tumor programmed death-ligand 1 status with response and survival was also evaluated. RESULTS: Of 160 treated patients (59 with nivolumab 3 mg/kg, 49 with nivolumab 1 mg/kg plus ipilimumab 3 mg/kg, 52 with nivolumab 3 mg/kg plus ipilimumab 1 mg/kg), 79% had received two or more prior therapies. At the data cutoff, investigator-assessed objective response rates were 12% (95% CI, 5% to 23%), 24% (95% CI, 13% to 39%), and 8% (95% CI, 2% to 19%) in the three groups, respectively. Responses were observed regardless of tumor programmed death-ligand 1 status. With a median follow-up of 28, 24, and 22 months across the three groups, 12-month progression-free survival rates were 8%, 17%, and 10%, respectively; 12-month OS rates were 39%, 35%, and 24%, respectively. Treatment-related grade 3/4 adverse events were reported in 17%, 47%, and 27% of patients in the three groups, respectively. CONCLUSION: Nivolumab and nivolumab plus ipilimumab demonstrated clinically meaningful antitumor activity, durable responses, encouraging long-term OS, and a manageable safety profile in patients with chemotherapy-refractory esophagogastric cancer. Phase III studies evaluating nivolumab or nivolumab plus ipilimumab in earlier lines of therapy for esophagogastric cancers are underway.
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Adenocarcinoma/tratamiento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias Esofágicas/tratamiento farmacológico , Unión Esofagogástrica/patología , Ipilimumab/administración & dosificación , Nivolumab/administración & dosificación , Adenocarcinoma/mortalidad , Adulto , Anciano , Anciano de 80 o más Años , Neoplasias Esofágicas/mortalidad , Femenino , Humanos , Ipilimumab/efectos adversos , Masculino , Persona de Mediana Edad , Nivolumab/efectos adversos , Supervivencia sin Progresión , Adulto JovenRESUMEN
Background: Immunotherapies have demonstrated efficacy across a diverse set of tumors supporting further evaluation in glioblastoma. The objective of this study was to evaluate the safety/tolerability and describe immune-mediated effects of nivolumab ± ipilimumab in patients with recurrent glioblastoma. Exploratory efficacy outcomes are also reported. Methods: Patients were randomized to receive nivolumab 3 mg/kg every 2 weeks (Q2W; NIVO3) or nivolumab 1 mg/kg + ipilimumab 3 mg/kg every 3 weeks (Q3W) for 4 doses, then nivolumab 3 mg/kg Q2W (NIVO1+IPI3). An alternative regimen of nivolumab 3 mg/kg + ipilimumab 1 mg/kg Q3W for 4 doses, then nivolumab 3 mg/kg Q2W (NIVO3+IPI1) was investigated in a nonrandomized arm. Results: Forty patients were enrolled (NIVO3, n = 10; NIVO1+IPI3, n = 10; NIVO3+IPI1, n = 20). The most common treatment-related adverse events (AEs) were fatigue (NIVO3, 30%; NIVO1+IPI3, 80%; NIVO3+IPI1, 55%) and diarrhea (10%, 70%, 30%, respectively). AEs leading to discontinuation occurred in 10% (NIVO3), 30% (NIVO1+IPI3), and 20% (NIVO3+IPI1) of patients. Three patients achieved a partial response (NIVO3, n = 1; NIVO3+IPI1, n = 2) and 8 had stable disease for ≥12 weeks (NIVO3, n = 2; NIVO1+IPI3, n = 2; NIVO3+IPI1, n = 4 [Response Assessment in Neuro-Oncology criteria]). Most patients (68%) had tumor-cell programmed death ligand-1 expression ≥1%. Immune-mediated effects mimicking radiographic progression occurred in 2 patients. Conclusions: Nivolumab monotherapy was better tolerated than nivolumab + ipilimumab; the tolerability of the combination was influenced by ipilimumab dose. These safety and exploratory findings merit further investigation of immunotherapies in glioblastoma.
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Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias Encefálicas/tratamiento farmacológico , Glioblastoma/tratamiento farmacológico , Recurrencia Local de Neoplasia/tratamiento farmacológico , Adulto , Anciano , Neoplasias Encefálicas/patología , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Glioblastoma/patología , Humanos , Ipilimumab/administración & dosificación , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia/patología , Nivolumab/administración & dosificación , PronósticoRESUMEN
PURPOSE: Nivolumab, a fully human immunoglobulin G4 programmed death-1 immune checkpoint inhibitor antibody, has demonstrated improved survival in previously treated patients with advanced non-small-cell lung cancer (NSCLC). CheckMate 012, a phase I, multicohort study, was conducted to explore the safety and efficacy of nivolumab as monotherapy or combined with current standard therapies in first-line advanced NSCLC. Here, we report results for nivolumab plus platinum-based doublet chemotherapy (PT-DC). PATIENTS AND METHODS: Patients (N = 56) received nivolumab (intravenously) plus PT-DC concurrently every 3 weeks for four cycles followed by nivolumab alone until progression or unacceptable toxicity. Regimens were nivolumab 10 mg/kg plus gemcitabine-cisplatin (squamous) or pemetrexed-cisplatin (nonsquamous) or nivolumab 5 or 10 mg/kg plus paclitaxel-carboplatin (all histologies). The primary objective was to assess safety and tolerability. Secondary objectives included objective response rate and 24-week progression-free survival rate (per Response Evaluation Criteria in Solid Tumors version 1.1); exploratory objectives included overall survival (OS) and response by tumor programmed death ligand-1 expression. RESULTS: No dose-limiting toxicities occurred during the first 6 weeks of treatment. Forty-five percent of patients (25 of 56 patients) reported grade 3 or 4 treatment-related adverse events (AEs); 7% of patients (n = 4) had pneumonitis. Twenty-one percent of patients (n = 12) discontinued all study therapy as a result of treatment-related AEs. Objective response rates for nivolumab 10 mg/kg plus gemcitabine-cisplatin, nivolumab 10 mg/kg plus pemetrexed-cisplatin, nivolumab 10 mg/kg plus paclitaxel-carboplatin, and nivolumab 5 mg/kg plus paclitaxel-carboplatin were 33%, 47%, 47%, and 43%, respectively; 24-week progression-free survival rates were 51%, 71%, 38%, and 51%, respectively; 2-year OS rates were 25%, 33%, 27%, and 62%, respectively. Responses were achieved regardless of tumor programmed death ligand-1 expression. CONCLUSION: The safety profile of nivolumab plus PT-DC was consistent with that expected for individual agents; however, treatment discontinuation related to AEs was greater with the combination. Encouraging activity was observed, especially for the nivolumab 5 mg/kg plus paclitaxel-carboplatin group, with a 2-year OS rate of 62%.
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Anticuerpos Monoclonales/administración & dosificación , Anticuerpos Monoclonales/efectos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Neoplasias Pulmonares/tratamiento farmacológico , Anciano , Antígeno B7-H1/biosíntesis , Carboplatino/administración & dosificación , Carboplatino/efectos adversos , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Cisplatino/administración & dosificación , Cisplatino/efectos adversos , Estudios de Cohortes , Desoxicitidina/administración & dosificación , Desoxicitidina/efectos adversos , Desoxicitidina/análogos & derivados , Supervivencia sin Enfermedad , Relación Dosis-Respuesta a Droga , Receptores ErbB/genética , Femenino , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Masculino , Persona de Mediana Edad , Nivolumab , Pemetrexed/administración & dosificación , Pemetrexed/efectos adversos , Proteínas Proto-Oncogénicas p21(ras)/genética , Tasa de Supervivencia , GemcitabinaRESUMEN
PURPOSE: Nivolumab, a programmed death-1 (PD-1) immune checkpoint inhibitor antibody, has demonstrated improved survival over docetaxel in previously treated advanced non-small-cell lung cancer (NSCLC). First-line monotherapy with nivolumab for advanced NSCLC was evaluated in the phase I, multicohort, Checkmate 012 trial. METHODS: Fifty-two patients received nivolumab 3 mg/kg intravenously every 2 weeks until progression or unacceptable toxicity; postprogression treatment was permitted per protocol. The primary objective was to assess safety; secondary objectives included objective response rate (ORR) and 24-week progression-free survival (PFS) rate; overall survival (OS) was an exploratory end point. RESULTS: Any-grade treatment-related adverse events (AEs) occurred in 71% of patients, most commonly: fatigue (29%), rash (19%), nausea (14%), diarrhea (12%), pruritus (12%), and arthralgia (10%). Ten patients (19%) reported grade 3 to 4 treatment-related AEs; grade 3 rash was the only grade 3 to 4 event occurring in more than one patient (n = 2; 4%). Six patients (12%) discontinued because of a treatment-related AE. The confirmed ORR was 23% (12 of 52), including four ongoing complete responses. Nine of 12 responses (75%) occurred by first tumor assessment (week 11); eight (67%) were ongoing (range, 5.3+ to 25.8+ months) at the time of data lock. ORR was 28% (nine of 32) in patients with any degree of tumor PD-ligand 1 expression and 14% (two of 14) in patients with no PD-ligand 1 expression. Median PFS was 3.6 months, and the 24-week PFS rate was 41% (95% CI, 27 to 54). Median OS was 19.4 months, and the 1-year and 18-month OS rates were 73% (95% CI, 59 to 83) and 57% (95% CI, 42 to 70), respectively. CONCLUSION: First-line nivolumab monotherapy demonstrated a tolerable safety profile and durable responses in first-line advanced NSCLC.
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Anticuerpos Monoclonales/uso terapéutico , Antineoplásicos/uso terapéutico , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Neoplasias Pulmonares/tratamiento farmacológico , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Monoclonales/efectos adversos , Antineoplásicos/efectos adversos , Carcinoma de Pulmón de Células no Pequeñas/patología , Estudios de Cohortes , Femenino , Humanos , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Estadificación de Neoplasias , NivolumabRESUMEN
Temperature variation on the host is known to influence ectoparasite distributions. Ectoparasites may also use temperature gradients between host regions when moving on the host; however, tests are rare. Feather-feeding wing lice (Phthiraptera: Ischnocera) spend the majority of their time on the flight feathers of their avian hosts where they insert their bodies between feather barbs to escape host preening. However, because wing lice feed on downy abdominal feathers, they must repeatedly migrate between the flight feathers and body regions of their hosts. We performed a series of experiments that tested thermo-orientation in wing lice and evaluated its potential use during louse migrations between host regions. We found that wing lice can rapidly and accurately locate nearby heat targets that approximate host temperatures (37 C), demonstrating a capacity for directed thermo-orientation. We next tested the preference of wing lice for temperatures found along migration routes between bird flight feathers and their body regions. Wing lice could distinguish between temperatures found within distinct bird regions, and lice that had recently fed preferred the cooler temperatures (32 C), similar to those within bird flight feathers where they typically reside. However, when starved for 18-20 hr, wing lice shifted their preferences toward temperatures typical of bird body regions where they feed (36 C), demonstrating an ability to use thermal cues when moving between bird regions. We discuss the use of thermal cues during louse migration and microhabitat selection, as well as other potential impacts of thermo-orientation on host-parasite interactions.
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Enfermedades de las Aves/parasitología , Temperatura Corporal , Columbidae/parasitología , Plumas/parasitología , Ischnocera/fisiología , Infestaciones por Piojos/veterinaria , Abdomen/parasitología , Animales , Temperatura Corporal/fisiología , Columbidae/anatomía & histología , Columbidae/metabolismo , Plumas/anatomía & histología , Interacciones Huésped-Parásitos , Infestaciones por Piojos/parasitología , Movimiento , Alas de Animales/parasitologíaRESUMEN
BACKGROUND: Kirsten rat sarcoma virus (KRAS) wild-type status determined using a locked nucleic acid (LNA)-mediated quantitative polymerase chain reaction (qPCR) clamping assay (LNA assay) predicted response to therapy in the CRYSTAL (Cetuximab Combined With Irinotecan in First-Line Therapy for Metastatic Colorectal Cancer) study. A companion KRAS diagnostic tool has been developed for routine clinical use (QIAGEN therascreen kit) (QIAGEN Manchester Ltd, Manchester, UK). We wanted to assess the concordance between the validated US Food and Drug Administration (FDA)-approved therascreen assay and the LNA assay in determining the KRAS status of a subset of patients enrolled in the CRYSTAL study. PATIENTS AND METHODS: DNA extracted from paraffin-embedded tumor sections was tested for KRAS status using the therascreen assay. Efficacy data from the CRYSTAL study were assessed to determine if the overall survival (OS) hazard ratio for cetuximab in patients identified as having KRAS wild-type status using the therascreen assay was equivalent to that in patients identified as KRAS wild-type using the LNA assay. This was determined by assessing if the concordance between the therascreen assay and the LNA assay met the minimum threshold (prespecified as 0.8) to achieve a significant difference in the OS hazard ratio in favor of the cetuximab + FOLFIRI (5-fluorouracil, leucovorin [folinic acid], irinotecan) arm in the KRAS wild-type population as identified using the therascreen assay. RESULTS: Of the 148 samples determined to be KRAS wild-type (therascreen assay), 141 (95.3%) samples were also KRAS wild-type (LNA assay) and 7 samples (4.7%) were KRAS mutant (LNA assay). The prespecified primary concordance measure p was 141/148 = 0.953 (95% confidence interval [CI], 0.905-0.981). The concordance was statistically significantly higher than the prespecified threshold of 0.8 for concordance between the therascreen assay and the LNA assay. Consistent with the concordance exceeding the prespecified threshold, the OS hazard ratio (cetuximab + FOLFIRI arm vs. FOLFIRI arm) in the KRAS wild-type population, determined by the therascreen assay, supported a significant benefit for cetuximab (ie, the 95% CI excluded 1) and was comparable to the OS hazard ratio observed in the CRYSTAL study KRAS wild-type population (LNA assay) even after adjustment for potentially confounding baseline variables. CONCLUSION: These results support the utility of the therascreen assay for identifying patients who may benefit from cetuximab therapy for metastatic colorectal cancer.