RESUMO
Pancreatic ductal adenocarcinoma (PDAC) exhibits elevated levels of autophagy, which promote tumor progression and treatment resistance. ATG4B is an autophagy-related cysteine protease under consideration as a potential therapeutic target, but it is largely unexplored in PDAC. Here, we investigated the clinical and functional relevance of ATG4B expression in PDAC. Using two PDAC patient cohorts, we found that low ATG4B mRNA or protein expression is associated with worse patient survival outcomes, poorly differentiated PDAC tumors and a lack of survival benefit from adjuvant chemotherapy. In PDAC cell lines, ATG4B knockout reduced proliferation, abolished processing of LC3B (also known as MAP1LC3B), and reduced GABARAP and GABARAPL1 levels, but increased ATG4A levels. ATG4B and ATG4A double knockout lines displayed a further reduction in proliferation, characterized by delays in G1-S phase transition and mitosis. Pro-LC3B accumulated aberrantly at the centrosome with a concomitant increase in centrosomal proteins PCM1 and CEP131, which was rescued by exogenous ATG4B. The two-stage cell cycle defects following ATG4B and ATG4A loss have important therapeutic implications for PDAC.
Assuntos
Adenocarcinoma , Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Humanos , Proteínas Relacionadas à Autofagia/genética , Proteínas Relacionadas à Autofagia/metabolismo , Cisteína Endopeptidases/genética , Cisteína Endopeptidases/metabolismo , Neoplasias Pancreáticas/genética , Autofagia/genética , Linhagem Celular Tumoral , Ciclo Celular/genética , Proliferação de Células/genética , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/metabolismo , Neoplasias PancreáticasRESUMO
BACKGROUND: Vascular endothelial growth factor is associated with reduced immune response and impaired anti-tumor activity. Combining antiangiogenic agents with immune checkpoint inhibition can overcome this immune suppression and enhance treatment efficacy. METHODS: This study investigated the combination of ziv-aflibercept anti-angiogenic therapy with pembrolizumab in patients with advanced melanoma resistant to anti-PD-1 treatment. Baseline and on-treatment plasma and PBMC samples were analyzed by multiplex protein assay and mass cytometry, respectively. RESULTS: In this Phase 1B study (NCT02298959), ten patients with advanced PD-1-resistant melanoma were treated with a combination of ziv-aflibercept (at 2-4 mg/kg) plus pembrolizumab (at 2 mg/kg), administered intravenously every 2 weeks. Two patients (20%) achieved a partial response, and two patients (20%) experienced stable disease (SD) as the best response. The two responders had mucosal melanoma, while both patients with SD had ocular melanoma. The combination therapy demonstrated clinical activity and acceptable safety, despite the occurrence of adverse events. Changes in plasma analytes such as platelet-derived growth factor and PD-L1 were explored, indicating potential alterations in myeloid cell function. Higher levels of circulating CXCL10 in non-responding patients may reflect pro-tumor activity. Specific subsets of γδ T cells were associated with poor clinical outcomes, suggesting impaired γδ T-cell function in non-responding patients. CONCLUSIONS: Although limited by sample size and follow-up, these findings highlight the potential of the combination of ziv-aflibercept antiangiogenic therapy with pembrolizumab in patients with advanced melanoma resistant to anti-PD-1 treatment and the need for further research to improve outcomes in anti-PD-1-resistant melanoma. TRIAL REGISTRATION NUMBER: NCT02298959.
Assuntos
Anticorpos Monoclonais Humanizados , Melanoma , Receptores de Fatores de Crescimento do Endotélio Vascular , Proteínas Recombinantes de Fusão , Humanos , Melanoma/tratamento farmacológico , Leucócitos Mononucleares , Fator A de Crescimento do Endotélio VascularRESUMO
AIM: We evaluated MK-8353 (small molecule inhibitor of extracellular signal-regulated kinase 1/2) plus selumetinib (mitogen-activated extracellular signal-regulated kinase 1/2 inhibitor) in patients with advanced solid tumors. METHODS: This phase 1b, open-label, dose-escalation study (NCT03745989) enrolled adults with histologically/cytologically documented, locally advanced/metastatic solid tumors. MK-8353/selumetinib dose combinations were intended to be investigated in sequence: 50/25, 100/50, 150/75, 200/75, 200/100, and 250/100. Each agent was administered orally BID 4 days on/3 days off in repeating cycles every 21 days. Primary objectives were safety and tolerability and to establish preliminary recommended phase 2 doses for combination therapy. RESULTS: Thirty patients were enrolled. Median (range) age was 61.5 (26-78) years and 93% had received previous cancer therapy. Among 28 patients in the dose-limiting toxicities [DLT]-evaluable population, 8 experienced DLTs: 1/11 (9%) in the MK-8353/selumetinib 100/50-mg dose level experienced a grade 3 DLT (urticaria), and 7/14 (50%) in the 150/75-mg dose level experienced grade 2/3 DLTs (n = 2 each of blurred vision, retinal detachment, vomiting; n = 1 each of diarrhea, macular edema, nausea, retinopathy). The DLT rate in the latter dose level exceeded the prespecified target DLT rate (~30%). Twenty-six patients (87%) experienced treatment-related adverse events (grade 3, 30%; no grade 4/5), most commonly diarrhea (67%), nausea (37%), and acneiform dermatitis (33%). Three patients (10%) experienced treatment-related adverse events leading to treatment discontinuation. Best response was stable disease in 14 patients (n = 10 with MK-8353/selumetinib 150/75 mg). CONCLUSION: MK-8353/selumetinib 50/25 mg and 100/50 mg had acceptable safety and tolerability, whereas 150/75 mg was not tolerable. No responses were observed.
Assuntos
Neoplasias , Adulto , Humanos , Pessoa de Meia-Idade , Idoso , Proteína Quinase 3 Ativada por Mitógeno , Neoplasias/tratamento farmacológico , Inibidores de Proteínas Quinases/efeitos adversos , Quinases de Proteína Quinase Ativadas por Mitógeno , Náusea/induzido quimicamente , Diarreia/induzido quimicamente , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Dose Máxima TolerávelRESUMO
BACKGROUND AND AIMS: Homologous recombination deficiency (HRD) in pancreatic ductal adenocarcinoma (PDAC), remains poorly defined beyond germline (g) alterations in BRCA1, BRCA2, and PALB2. METHODS: We interrogated whole genome sequencing (WGS) data on 391 patients, including 49 carriers of pathogenic variants (PVs) in gBRCA and PALB2. HRD classifiers were applied to the dataset and included (1) the genomic instability score (GIS) used by Myriad's MyChoice HRD assay; (2) substitution base signature 3 (SBS3); (3) HRDetect; and (4) structural variant (SV) burden. Clinical outcomes and responses to chemotherapy were correlated with HRD status. RESULTS: Biallelic tumor inactivation of gBRCA or PALB2 was evident in 43 of 49 germline carriers identifying HRD-PDAC. HRDetect (score ≥0.7) predicted gBRCA1/PALB2 deficiency with highest sensitivity (98%) and specificity (100%). HRD genomic tumor classifiers suggested that 7% to 10% of PDACs that do not harbor gBRCA/PALB2 have features of HRD. Of the somatic HRDetecthi cases, 69% were attributed to alterations in BRCA1/2, PALB2, RAD51C/D, and XRCC2, and a tandem duplicator phenotype. TP53 loss was more common in BRCA1- compared with BRCA2-associated HRD-PDAC. HRD status was not prognostic in resected PDAC; however in advanced disease the GIS (P = .02), SBS3 (P = .03), and HRDetect score (P = .005) were predictive of platinum response and superior survival. PVs in gATM (n = 6) or gCHEK2 (n = 2) did not result in HRD-PDAC by any of the classifiers. In 4 patients, BRCA2 reversion mutations associated with platinum resistance. CONCLUSIONS: Germline and parallel somatic profiling of PDAC outperforms germline testing alone in identifying HRD-PDAC. An additional 7% to 10% of patients without gBRCA/PALB2 mutations may benefit from DNA damage response agents.
Assuntos
Carcinoma Ductal Pancreático/genética , Proteína do Grupo de Complementação N da Anemia de Fanconi/genética , Genes BRCA1 , Genes BRCA2 , Neoplasias Pancreáticas/genética , Reparo de DNA por Recombinação , Idoso , Alelos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma Ductal Pancreático/terapia , Cisplatino/administração & dosagem , Proteínas de Ligação a DNA/genética , Desoxicitidina/administração & dosagem , Desoxicitidina/análogos & derivados , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Fluoruracila/uso terapêutico , Instabilidade Genômica , Mutação em Linhagem Germinativa , Recombinação Homóloga , Humanos , Irinotecano/uso terapêutico , Leucovorina/uso terapêutico , Masculino , Pessoa de Meia-Idade , Oxaliplatina/uso terapêutico , Pancreatectomia , Neoplasias Pancreáticas/terapia , Prognóstico , Sensibilidade e Especificidade , Taxa de Sobrevida , Proteína Supressora de Tumor p53/genética , Sequenciamento Completo do Genoma , GencitabinaRESUMO
OBJECTIVE: To describe the clinical, pathological and genomic characteristics of pancreatic cancer with DNA mismatch repair deficiency (MMRD) and proficiency (MMRP). DESIGN: We identified patients with MMRD and MMRP pancreatic cancer in a clinical cohort (N=1213, 519 with genetic testing, 53 with immunohistochemistry (IHC)) and a genomic cohort (N=288 with whole-genome sequencing (WGS)). RESULTS: 12 out of 1213 (1.0%) in the clinical cohort were MMRD by IHC or WGS. Of the 14 patients with Lynch syndrome, 3 (21.4%) had an MMRP pancreatic cancer by IHC, and 4 (28.6%) were excluded because tissue was unavailable for testing. MMRD cancers had longer overall survival after surgery (weighted HR after coarsened exact matching 0.11, 95% CI 0.02 to 0.78, p=0.001). One patient with an unresectable MMRD cancer has an ongoing partial response 3 years after starting treatment with PD-L1/CTLA-4 inhibition. This tumour showed none of the classical histopathological features of MMRD. 9 out of 288 (3.1%) tumours with WGS were MMRD. Despite markedly higher tumour mutational burden and neoantigen loads, MMRD cancers were significantly less likely to have mutations in usual pancreatic cancer driver genes like KRAS and SMAD4, but more likely to have mutations in genes that drive cancers with microsatellite instability like ACV2RA and JAK1. MMRD tumours were significantly more likely to have a basal-like transcriptional programme and elevated transcriptional markers of immunogenicity. CONCLUSIONS: MMRD pancreatic cancers have distinct clinical, pathological and genomic profiles. Patients with MMRD pancreatic cancer should be considered for basket trials targeting enhanced immunogenicity or the unique genomic drivers in these malignancies.
Assuntos
Adenocarcinoma/genética , Distúrbios no Reparo do DNA/genética , Neoplasias Pancreáticas/genética , Adenocarcinoma/patologia , Neoplasias Colorretais Hereditárias sem Polipose/genética , Neoplasias Colorretais Hereditárias sem Polipose/patologia , Distúrbios no Reparo do DNA/patologia , Feminino , Testes Genéticos , Genômica , Humanos , Masculino , Instabilidade de Microssatélites , Mutação , Ontário , Neoplasias Pancreáticas/patologia , Estudos Retrospectivos , Sequenciamento Completo do GenomaRESUMO
The mixture of epithelial and stromal components in pancreatic ductal adenocarcinoma (PDAC) may confound sequencing-based studies of tumor gene expression. Virtual microdissection has been suggested as a bioinformatics approach to segment the aforementioned components, and subsequent prognostic gene sets have emerged from this research. We examined the prognostic signature from the epithelial gene set of one such study using laser capture microdissected (LCM) epithelial samples. We also examined this gene set in matched stromal samples to determine whether prognostic findings were specific to the epithelium. LCM samples from 48 long-term and 48 short-term PDAC survivors were obtained. The resultant epithelial and stromal components were subjected to direct mRNA quantification using a 49 gene published PDAC classifier. Component-specific unsupervised hierarchical clustering was used to derive groups and survival differences were quantified. Immunohistochemical validation of particular genes was performed in an independent cohort. Clustering in the epithelial component yielded prognostic differences in univariable analysis (P = .02), but those differences were not significant when controlled for other clinicopathologic covariates (P = .06). Clustering in the stromal component yielded prognostic differences that persisted in the presence of other clinicopathologic covariates (P = .0005). Validation of selected genes in the epithelium (KRT6A-negative prognostic [P = .004]) and stroma (LY6D-improved prognostic [P = .01] and CTSV-negative prognostic [P = .0002]) demonstrated statistical independence in multivariable analysis. Although the genes used in this study were originally identified as being representative of the epithelial component of PDAC, their expression in the stroma appears to provide additional information that may aid in improved prognostication.
Assuntos
Carcinoma Ductal Pancreático/patologia , Neoplasias Pancreáticas/patologia , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/metabolismo , Análise por Conglomerados , Estudos de Coortes , Células Epiteliais/patologia , Formaldeído , Expressão Gênica , Humanos , Microdissecção e Captura a Laser , Linfonodos/patologia , Invasividade Neoplásica , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Inclusão em Parafina , Nervos Periféricos/patologia , Prognóstico , Células Estromais/patologia , Análise de Sobrevida , Fixação de TecidosRESUMO
BACKGROUND: Neuregulin 1 (NRG1) fusions, which activate ErbB signaling, are rare oncogenic drivers in multiple tumor types. Afatinib is a pan-ErbB family inhibitor that may be an effective treatment for NRG1 fusion-driven tumors. PATIENTS AND METHODS: This report summarizes pertinent details, including best tumor response to treatment, for six patients with metastatic NRG1 fusion-positive tumors treated with afatinib. RESULTS: The six cases include four female and two male patients who ranged in age from 34 to 69 years. Five of the cases are patients with lung cancer, including two patients with invasive mucinous adenocarcinoma and three patients with nonmucinous adenocarcinoma. The sixth case is a patient with colorectal cancer. NRG1 fusion partners for the patients with lung cancer were either CD74 or SDC4. The patient with colorectal cancer harbored a novel POMK-NRG1 fusion and a KRAS mutation. Two patients received afatinib as first- or second-line therapy, three patients received the drug as third- to fifth-line therapy, and one patient received afatinib as fifteenth-line therapy. Best response with afatinib was stable disease in two patients (duration up to 16 months when combined with local therapies) and partial response (PR) of >18 months in three patients, including one with ongoing PR after 27 months. The remaining patient had a PR of 5 months with afatinib 40 mg/day, then another 6 months after an increase to 50 mg/day. CONCLUSION: This report reviews previously published metastatic NRG1 fusion-positive tumors treated with afatinib and summarizes six previously unpublished cases. The latter include several with a prolonged response to treatment (>18 months), as well as the first report of efficacy in NRG1 fusion-positive colorectal cancer. This adds to the growing body of evidence suggesting that afatinib can be effective in patients with NRG1 fusion-positive tumors. KEY POINTS: NRG1 fusions activate ErbB signaling and have been identified as oncogenic drivers in multiple solid tumor types. Afatinib is a pan-ErbB family inhibitor authorized for the treatment of advanced non-small cell lung cancer that may be effective in NRG1 fusion-driven tumors. This report summarizes six previously unpublished cases of NRG1 fusion-driven cancers treated with afatinib, including five with metastatic lung cancer and one with metastatic colorectal cancer. Several patients showed a prolonged response of >18 months with afatinib treatment. This case series adds to the evidence suggesting a potential role for afatinib in this area of unmet medical need.
Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Adulto , Afatinib/uso terapêutico , Idoso , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Feminino , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Masculino , Pessoa de Meia-Idade , Mutação , Neuregulina-1/genética , Proteínas de Fusão Oncogênica/genética , Inibidores de Proteínas QuinasesRESUMO
INTRODUCTION: Carcinogenesis is driven by an array of complex genomic patterns; these patterns can render an individual resistant or sensitive to certain chemotherapy agents. The Personalized Oncogenomics (POG) project at BC Cancer has performed integrative genomic analysis of whole tumour genomes and transcriptomes for over 700 patients with advanced cancers, with an aim to predict therapeutic sensitivities. The aim of this study was to utilize the POG genomic data to evaluate a discrete set of biomarkers associated with chemo-sensitivity or-resistance in advanced stage breast and colorectal cancer POG patients. METHODS: This was a retrospective multi-centre analysis across all BC CANCER sites. All breast and colorectal cancer patients enrolled in the POG program between July 1, 2012 and November 30, 2016 were eligible for inclusion. Within the breast cancer population, those treated with capecitabine, paclitaxel, and everolimus were analyzed, and for the colorectal cancer patients, those treated with capecitabine, bevacizumab, irinotecan, and oxaliplatin were analyzed. The expression levels of the selected biomarkers of interest (EPHB4, FIGF, CD133, DICER1, DPYD, TYMP, TYMS, TAP1, TOP1, CKDN1A, ERCC1, GSTP1, BRCA1, PTEN, ABCB1, TLE3, and TXNDC17) were reported as mRNA percentiles. RESULTS: For the breast cancer population, there were 32 patients in the capecitabine cohort, 15 in the everolimus cohort, and 12 in the paclitaxel cohort. For the colorectal cancer population, there were 29 patients in the bevacizumab cohort, 12 in the oxaliplatin cohort, 29 in the irinotecan cohort, and 6 in the capecitabine cohort. Of the biomarkers evaluated, the strongest associations were found between Bevacizumab-based therapy and DICER1 (P = 0.0445); and between capecitabine therapy and TYMP (P = 0.0553). CONCLUSIONS: Among breast cancer patients, higher TYMP expression was associated with sensitivity to capecitabine. Among colorectal cancer patients, higher DICER1 expression was associated with sensitivity to bevacizumab-based therapy. This study supports further assessment of the potential predictive value of mRNA expression of these genomic biomarkers.
Assuntos
Neoplasias Colorretais , Protocolos de Quimioterapia Combinada Antineoplásica , Bevacizumab/uso terapêutico , Biomarcadores Tumorais/genética , Capecitabina/uso terapêutico , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , RNA Helicases DEAD-box , Fluoruracila/uso terapêutico , Genômica , Humanos , Estudos Retrospectivos , Ribonuclease IIIRESUMO
BACKGROUND: The majority of patients with advanced gastrointestinal stromal tumours (GISTs) develop resistance to imatinib and sunitinib, the standard of care for these patients. This study evaluated the combination of buparlisib, an oral phosphoinositide 3-kinase (PI3K) inhibitor, with imatinib in patients with advanced GIST, who have failed prior therapy with imatinib and sunitinib. METHODS: This Phase 1b, multicentre, open-label study aimed to determine the maximum tolerated dose (MTD) and/or a recommended Phase 2 dose of buparlisib in combination with 400 mg of imatinib through a dose-escalation part and a dose-expansion part, and also evaluated the clinical profile of the combination. RESULTS: Sixty patients were enrolled, including 25 in the dose-escalation part and 35 in the dose-expansion part. In the combination, MTD of buparlisib was established as 80 mg. No partial or complete responses were observed. The estimated median progression-free survival was 3.5 months in the expansion phase. Overall, 98.3% of patients had treatment-related adverse events (AEs), including 45% with grade 3 or 4 AEs. CONCLUSIONS: Buparlisib in combination with imatinib provided no additional benefit compared with currently available therapies. Due to the lack of objective responses, further development of this combination was not pursued for third-line/fourth-line advanced/metastatic GIST. TRIAL REGISTRATION NUMBER: NCT01468688.
Assuntos
Aminopiridinas/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Gastrointestinais/tratamento farmacológico , Tumores do Estroma Gastrointestinal/tratamento farmacológico , Mesilato de Imatinib/administração & dosagem , Morfolinas/administração & dosagem , Inibidores de Fosfoinositídeo-3 Quinase/administração & dosagem , Sunitinibe/administração & dosagem , Adulto , Idoso , Aminopiridinas/efeitos adversos , Feminino , Neoplasias Gastrointestinais/mortalidade , Tumores do Estroma Gastrointestinal/mortalidade , Humanos , Mesilato de Imatinib/efeitos adversos , Masculino , Transtornos Mentais/induzido quimicamente , Pessoa de Meia-Idade , Morfolinas/efeitos adversosRESUMO
BACKGROUND & AIMS: Most pancreatic ductal adenocarcinomas (PDACs) express an activated form of KRAS, become hypoxic and dysplastic, and are refractory to chemo and radiation therapies. To survive in the hypoxic environment, PDAC cells upregulate enzymes and transporters involved in pH regulation, including the extracellular facing carbonic anhydrase 9 (CA9). We evaluated the effect of blocking CA9, in combination with administration of gemcitabine, in mouse models of pancreatic cancer. METHODS: We knocked down expression of KRAS in human (PK-8 and PK-1) PDAC cells with small hairpin RNAs. Human and mouse (KrasG12D/Pdx1-Cre/Tp53/RosaYFP) PDAC cells were incubated with inhibitors of MEK (trametinib) or extracellular signal-regulated kinase (ERK), and some cells were cultured under hypoxic conditions. We measured levels and stability of the hypoxia-inducible factor 1 subunit alpha (HIF1A), endothelial PAS domain 1 protein (EPAS1, also called HIF2A), CA9, solute carrier family 16 member 4 (SLC16A4, also called MCT4), and SLC2A1 (also called GLUT1) by immunoblot analyses. We analyzed intracellular pH (pHi) and extracellular metabolic flux. We knocked down expression of CA9 in PDAC cells, or inhibited CA9 with SLC-0111, incubated them with gemcitabine, and assessed pHi, metabolic flux, and cytotoxicity under normoxic and hypoxic conditions. Cells were also injected into either immune-compromised or immune-competent mice and growth of xenograft tumors was assessed. Tumor fragments derived from patients with PDAC were surgically ligated to the pancreas of mice and the growth of tumors was assessed. We performed tissue microarray analyses of 205 human PDAC samples to measure levels of CA9 and associated expression of genes that regulate hypoxia with outcomes of patients using the Cancer Genome Atlas database. RESULTS: Under hypoxic conditions, PDAC cells had increased levels of HIF1A and HIF2A, upregulated expression of CA9, and activated glycolysis. Knockdown of KRAS in PDAC cells, or incubation with trametinib, reduced the posttranscriptional stabilization of HIF1A and HIF2A, upregulation of CA9, pHi, and glycolysis in response to hypoxia. CA9 was expressed by 66% of PDAC samples analyzed; high expression of genes associated with metabolic adaptation to hypoxia, including CA9, correlated with significantly reduced survival times of patients. Knockdown or pharmacologic inhibition of CA9 in PDAC cells significantly reduced pHi in cells under hypoxic conditions, decreased gemcitabine-induced glycolysis, and increased their sensitivity to gemcitabine. PDAC cells with knockdown of CA9 formed smaller xenograft tumors in mice, and injection of gemcitabine inhibited tumor growth and significantly increased survival times of mice. In mice with xenograft tumors grown from human PDAC cells, oral administration of SLC-0111 and injection of gemcitabine increased intratumor acidosis and increased cell death. These tumors, and tumors grown from PDAC patient-derived tumor fragments, grew more slowly than xenograft tumors in mice given control agents, resulting in longer survival times. In KrasG12D/Pdx1-Cre/Tp53/RosaYFP genetically modified mice, oral administration of SLC-0111 and injection of gemcitabine reduced numbers of B cells in tumors. CONCLUSIONS: In response to hypoxia, PDAC cells that express activated KRAS increase expression of CA9, via stabilization of HIF1A and HIF2A, to regulate pH and glycolysis. Disruption of this pathway slows growth of PDAC xenograft tumors in mice and might be developed for treatment of pancreatic cancer.
Assuntos
Antígenos de Neoplasias/metabolismo , Anidrase Carbônica IX/metabolismo , Carcinoma Ductal Pancreático/enzimologia , Neoplasias Pancreáticas/enzimologia , Proteínas Proto-Oncogênicas p21(ras)/genética , Microambiente Tumoral , Animais , Antígenos de Neoplasias/genética , Antimetabólitos Antineoplásicos/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Anidrase Carbônica IX/antagonistas & inibidores , Anidrase Carbônica IX/genética , Inibidores da Anidrase Carbônica/farmacologia , Carcinoma Ductal Pancreático/tratamento farmacológico , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/patologia , Hipóxia Celular , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Desoxicitidina/análogos & derivados , Desoxicitidina/farmacologia , Feminino , Regulação Neoplásica da Expressão Gênica , Predisposição Genética para Doença , Glicólise/efeitos dos fármacos , Humanos , Concentração de Íons de Hidrogênio , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Camundongos SCID , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Fenótipo , Compostos de Fenilureia/farmacologia , Transdução de Sinais , Sulfonamidas/farmacologia , Carga Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto , GencitabinaRESUMO
Introduction Given the high level of uncertainty surrounding the outcomes of early phase clinical trials, whole genome and transcriptome analysis (WGTA) can be used to optimize patient selection and study assignment. In this retrospective analysis, we reviewed the impact of this approach on one such program. Methods Patients with advanced malignancies underwent fresh tumor biopsies as part of our personalized medicine program (NCT02155621). Tumour molecular data were reviewed for potentially clinically actionable findings and patients were referred to the developmental therapeutics program. Outcomes were reviewed in all patients, including those where trial selection was driven by molecular data (matched) and those where there was no clear molecular rationale (unmatched). Results From January 2014 to January 2018, 28 patients underwent WGTA and enrolled in clinical trials, including 2 patients enrolled in two trials. Fifteen patients were matched to a treatment based on a molecular target. Five patients were matched to a trial based upon single-gene DNA changes, all supported by RNA data. Ten cases were matched on the basis of genome-wide data (n = 4) or RNA gene expression only (n = 6). With a median follow-up of 6.7 months, the median time on treatment was 8.2 weeks. Discussion When compared to single-gene DNA-based data alone, WGTA led to a 3-fold increase in treatment matching. In a setting where there is a high level of uncertainty around both the investigational agents and the biomarkers, more data are needed to fully evaluate the impact of routine use of WGTA.
Assuntos
Perfilação da Expressão Gênica , Neoplasias/tratamento farmacológico , Neoplasias/genética , Sequenciamento Completo do Genoma , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias/patologia , Seleção de Pacientes , Medicina de Precisão , Estudos Retrospectivos , Falha de TratamentoRESUMO
BACKGROUND: Programmed cell death 1 (PD1) inhibitors have recently shown promising anti-cancer effects in a number of solid tumor types. A predictive biomarker to this class of drugs has not been clearly identified; however, overexpression of the PD1 ligand (PD-L1) has shown particular promise in lung adenocarcinoma. In this study, we explore the staining characteristics, prevalence, and clinico-molecular correlates of PD-L1 overexpression in pancreatic ductal adenocarcinoma (PDAC). METHODS: A tissue microarray (TMA) was constructed from cases of resected PDAC. PD-L1 immunohistochemistry (IHC) was performed using the SP142 primary antibody. Immunohistochemical assessment for deficient mismatch repair status (MMRd), CD3 and CD8 were performed. All biomarkers were assessed independently by two anatomical pathologists and consensus achieved on all cases. Survival analysis was performed using three thresholds (> = 1%, >5% and >10%) for tumor cell membrane staining. RESULTS: Two-hundred fifty-two cases were included in the TMA and evaluable by IHC. Thirty-one (12%), 17 (7%), 12(5%) cases were positive at percentage cut offs of >0, >5, and >10% respectively. Increased PD-L1 expression was associated with inferior prognosis (p = 0.0367). No statistically significant association was identified between PD-L1 status and MMR status or tumor infiltrating lymphocytes. CONCLUSIONS: This data suggests that there is an inverse relationship between PD-L1 expression and disease specific survival times in resected PDAC. Consequently, this association may represent a phenotype where increased PD-L1 expression has an effect on tumor biology and could therefore identify a subgroup where PD1 blockade could have enhanced effectiveness.
Assuntos
Antígeno B7-H1/metabolismo , Biomarcadores Tumorais , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/mortalidade , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/mortalidade , Idoso , Antígeno B7-H1/genética , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/patologia , Quimioterapia Adjuvante , Reparo de Erro de Pareamento de DNA , Feminino , Expressão Gênica , Humanos , Imuno-Histoquímica , Linfócitos do Interstício Tumoral/imunologia , Linfócitos do Interstício Tumoral/metabolismo , Linfócitos do Interstício Tumoral/patologia , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Invasividade Neoplásica , Estadiamento de Neoplasias , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Prognóstico , Modelos de Riscos Proporcionais , Análise Serial de TecidosRESUMO
BACKGROUND: There is crosstalk between the ANG-Tie2 and the PI3K/Akt/mTOR pathways. Combined ANG1/2 and mTOR blockade may have additive anti-cancer activity. The combination of trebananib, an inhibitor of ANG1/2-Tie2 interaction, with temsirolimus was evaluated in patients with advanced solid tumors to determine tolerability, maximum tolerated dose (MTD), and preliminary antitumor activity. METHODS: Patients were enrolled using 3 + 3 design, and were given intravenous trebananib and temsirolimus on Day 1, 8, 15 and 22 of a 28-day cycle. Dose limiting toxicities (DLTs) were evaluated during cycle 1. Peripheral blood was collected for evaluation of Tie2-expressing monocytes (TEMs) and thymidine phosphorylase (TP). Sparse pharmacokinetic (PK) sampling for trebananib drug levels was performed on Day 1 and 8 of cycle 2. RESULTS: Twenty-one patients were enrolled, 6 at dose level (DL) 1, 7 at DL -1, and 8 at DL -2. No effect of temsirolimus on trebananib PK was observed. The most common treatment-related adverse events (AEs) were: fatigue (81 %), edema (62 %), anorexia (57 %), nausea (52 %), rash (43 %) and mucositis (43 %). The most common grade ≥ 3 AEs included lymphopenia (28 %) and fatigue (28 %). The MTD was exceeded at DL-2. Of 18 response evaluable patients, 1 partial response was observed (ER+/HER2-/PIK3CA mutant breast cancer) and 4 patients had prolonged SD ≥ 24 weeks. No correlation with clinical benefit was observed with change in number TEMs or TP expression in TEMs with treatment. CONCLUSIONS: The MTD was exceeded at trebananib 10 mg/kg weekly and temsirolimus 20 mg weekly, with frequent overlapping toxicities including fatigue, edema, and anorexia.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Neoplasias/tratamento farmacológico , Adulto , Idoso , Anorexia/induzido quimicamente , Anorexia/epidemiologia , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Edema/induzido quimicamente , Edema/epidemiologia , Fadiga/induzido quimicamente , Fadiga/epidemiologia , Feminino , Humanos , Masculino , Dose Máxima Tolerável , Pessoa de Meia-Idade , Neoplasias/patologia , Proteínas Recombinantes de Fusão/administração & dosagem , Sirolimo/administração & dosagem , Sirolimo/análogos & derivados , Resultado do TratamentoRESUMO
PURPOSE: There are concerns regarding potential negative effects of prophylactic treatment of epidermal growth factor receptor (EGFR)-inhibitor-related rashes on metastatic colorectal cancer (mCRC) outcomes. We aimed to characterize treatment patterns of EGFR-inhibitor-induced rashes and evaluate prophylactic versus reactive approaches to rash management in relation to overall survival (OS). METHODS: Patients diagnosed with KRAS wild-type mCRC from July 2010 to June 2012 in British Columbia and prescribed cetuximab or panitumumab were reviewed to describe patterns of use of oral antibiotics and steroid creams. Using Cox regression, the relationship between prophylactic versus reactive rash management and OS was characterized. RESULTS: A total 119 patients were analyzed: median age was 63 years, 61 % were male, 34 % received cetuximab, 66 % received panitumumab, and median number of EGFR inhibitor treatment was nine cycles. Rash occurred in >90 % of patients, and reactive was favored over prophylactic treatment (66 vs. 34 %). Older patients and those with Eastern Cooperative Oncology Group (ECOG) performance status 0/1 were more likely to receive prophylactic creams (44 vs. 20 % for age <60, p = 0.01) and oral antibiotics (62 vs. 12 % for ECOG ≥2, p = 0.01), respectively. Median OS was 7.0 months. The number of treatment cycles and OS were similar in both prophylactic and reactive groups (both p > 0.05). In Cox regression, ECOG >2 correlated with worse survival (hazard ratio (HR) 22.01, 95 % confidence interval (CI) 5.25-92.30, p < 0.01). However, survival outcomes were similar between patients prescribed antibiotics prophylactically versus reactively (HR = 1.10, 95 % CI 0.43-2.80, p = 0.85), and steroid creams prophylactically versus reactively (HR = 2.00, 95 % CI 0.58-6.92, p = 0.27). CONCLUSION: Prophylactic treatment of EGFR-inhibitor-related rashes is associated with similar outcomes compared to reactive rash treatment in mCRC.
Assuntos
Erupções Acneiformes/tratamento farmacológico , Antineoplásicos/efeitos adversos , Neoplasias Colorretais/tratamento farmacológico , Tratamento Farmacológico/métodos , Receptores ErbB/antagonistas & inibidores , Exantema/tratamento farmacológico , Metástase Neoplásica/tratamento farmacológico , Erupções Acneiformes/induzido quimicamente , Erupções Acneiformes/prevenção & controle , Idoso , Anticorpos Monoclonais/efeitos adversos , Colúmbia Britânica , Cetuximab/efeitos adversos , Exantema/induzido quimicamente , Exantema/prevenção & controle , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Panitumumabe , Resultado do TratamentoRESUMO
Polymorphisms in the vascular endothelial growth factor (VEGF)/angiogenesis pathway have been implicated previously in cancer risk, prognosis and response to therapy including in esophageal adenocarcinoma. Prior esophageal adenocarcinoma studies focused on using candidate polymorphisms, limiting the discovery of novel polymorphisms. Here, we applied the tagSNP (single nucleotide polymorphism) approach to identify new VEGF pathway polymorphisms associated with esophageal adenocarcinoma prognosis and validated them in an independent cohort of esophageal adenocarcinoma patients. In 231 esophageal adenocarcinoma patients of all stages/treatment plans, 58 genetic polymorphisms (18 KDR, 7 VEGFA and 33 FLT1) selected through tagging and assessment of predicted function were genotyped. Cox-proportional hazard models adjusted for important socio-demographic and clinico-pathological factors were applied to assess the association of genetic polymorphisms with overall survival (OS) and progression-free survival (PFS). Significantly associated polymorphisms were then validated in an independent cohort of 137 esophageal adenocarcinoma patients. Among the 231 discovery cohort patients, 86% were male, median diagnosis age was 64 years, 34% were metastatic at diagnosis and median OS and PFS were 20 and 12 months, respectively. KDR rs17709898 was found significantly associated with PFS (adjusted hazard ratio, aHR = 0.69, 95% confidence interval (CI): 0.53-0.90; P = 5.9E-3). FLT1 rs3794405 and rs678714 were significantly associated with OS (aHR = 1.44, 95% CI: 1.04-1.99; P = 0.03 and aHR = 1.50, 95% CI: 1.01-2.24; P = 0.045, respectively). No VEGFA polymorphisms were found significantly associated with either outcome. Upon validation, FLT1 rs3794405 remained strongly associated with OS (aHR = 1.59, 95% CI: 1.04-2.44; P = 0.03). FLT1 rs3794405 is significantly associated with OS in esophageal adenocarcinoma, whereby each variant allele confers a 45-60% increased risk of mortality. Validation and evaluation of this association in other cancer sites are warranted.
Assuntos
Adenocarcinoma/genética , Neoplasias Esofágicas/genética , Neovascularização Patológica/genética , Fator A de Crescimento do Endotélio Vascular/genética , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/genética , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/genética , Adenocarcinoma/mortalidade , Adulto , Idoso , Idoso de 80 Anos ou mais , Intervalo Livre de Doença , Neoplasias Esofágicas/mortalidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genética , Estudos Prospectivos , Inquéritos e QuestionáriosRESUMO
BACKGROUND: Adjuvant chemotherapy (AC) is frequently considered in patients with stage II colon cancer who are considered to be at high risk. However, to the authors' knowledge, the survival benefits associated with AC in these patients remain largely unproven. In the current study, the authors sought to examine the use of AC in patients with AJCC stage II colon cancer and to compare the impact of AC on outcomes in patients with high-risk versus low-risk disease in a population-based setting. METHODS: Patients with stage II colon cancer who were evaluated at 1 of 5 regional cancer centers in British Columbia from 1999 to 2008 were analyzed. Kaplan-Meier and Cox regression methods were used to correlate high-risk versus low-risk status and receipt of AC with recurrence-free survival (RFS), disease-specific survival (DSS), and overall survival (OS). RESULTS: A total of 1697 patients were identified: 1286 (76%) with high-risk and 411 (24%) with low-risk disease, among whom 373 (29%) and 51 (12%),respectively, received AC. Individuals with high-risk disease treated with AC were younger (median age, 62 years vs 72 years; P<.001) and had better Eastern Cooperative Oncology Group performance status (0/1: 47% vs 33%; P = .001). For high-risk patients, AC was associated with improved OS (hazard ratio [HR], 0.65; 95% confidence interval [95% CI], 0.50-0.83 [P = .001]). However, no significant benefits with regard to RFS or DSS were observed. Subgroup analyses revealed that AC in patients with T4 disease was associated with significantly improved RFS (HR, 0.63; 95% CI, 0.42-0.95 [P = .03]), DSS (HR, 0.59; 95% CI, 0.37-0.93 [P = .02]), and OS (HR, 0.50; 95% CI, 0.33-0.77 [P = .002]). For patients with low-risk disease, AC was associated with inferior RFS (HR, 2.18; 95% CI, 1.00-4.79 [P = .05]) and DSS (HR, 3.01; 95% CI, 1.10-8.23 [P = .03]). CONCLUSIONS: In this population-based analysis, AC was associated with an OS advantage in high-risk patients, most likely due to patient selection. RFS, DSS, and OS benefits were mainly observed in patients with T4 disease, suggesting a limited role for AC in patients deemed to be high risk by non-T4 features.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias do Colo/tratamento farmacológico , Neoplasias do Colo/patologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Quimioterapia Adjuvante , Neoplasias do Colo/complicações , Intervalo Livre de Doença , Esquema de Medicação , Feminino , Humanos , Obstrução Intestinal/etiologia , Perfuração Intestinal/etiologia , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Razão de Chances , Seleção de Pacientes , Prognóstico , Modelos de Riscos Proporcionais , Medição de Risco , Fatores de Risco , Resultado do TratamentoRESUMO
Deficiencies in DNA mismatch repair have been associated with inferior response to 5-FU in colorectal cancer. Pancreatic ductal adenocarcinoma is similarly treated with pyrimidine analogs, yet the predictive value of mismatch repair status for response to these agents has not been examined in this malignancy. A tissue microarray with associated clinical outcome, comprising 254 resected pancreatic ductal adenocarcinoma patients was stained for four mismatch repair proteins (MLH1, MSH2, MSH6 and PMS2). Mismatch repair deficiency and proficiency was determined by the absence or presence of uniform nuclear staining in tumor cells, respectively. Cases identified as mismatch repair deficient on the tissue microarray were confirmed by immunohistochemistry on whole slide sections. Of the 265 cases, 78 (29%) received adjuvant treatment with a pyrimidine analog and 41 (15%) showed a mismatch repair-deficient immunoprofile. Multivariable disease-specific survival in the mismatch repair-proficient cohort demonstrated that adjuvant chemotherapy, regional lymph-node status, gender, and the presence of tumor budding were significant independent prognostic variables (P≤0.04); however, none of the eight clinico-pathologic covariates examined in the mismatch repair-deficient cohort were of independent prognostic significance. Univariable assessment of disease-specific survival revealed an almost identical survival profile for both treated and untreated patients with a mismatch repair-deficient profile, while treatment in the mismatch repair-proficient cohort conferred a greater than 10-month median disease-specific survival advantage over their untreated counterparts (P=0.0018). In this cohort, adjuvant chemotherapy with a pyrimidine analog conferred no survival advantage to mismatch repair-deficient pancreatic ductal adenocarcinoma patients. Mismatch repair immunoprofiling is a feasible predictive marker in pancreatic ductal adenocarcinoma patients, and further prospective evaluation of this finding is warranted.
Assuntos
Antineoplásicos/uso terapêutico , Carcinoma Ductal Pancreático/genética , Reparo de Erro de Pareamento de DNA/genética , Resistencia a Medicamentos Antineoplásicos/genética , Neoplasias Pancreáticas/genética , Idoso , Carcinoma Ductal Pancreático/tratamento farmacológico , Carcinoma Ductal Pancreático/patologia , Quimioterapia Adjuvante , Feminino , Humanos , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/patologia , Modelos de Riscos Proporcionais , Análise Serial de TecidosRESUMO
Extraordinary advancements in sequencing technology have made what was once a decade-long multi-institutional endeavor into a methodology with the potential for practical use in a clinical setting. We therefore set out to examine the clinical value of next-generation sequencing by enrolling patients with incurable or ambiguous tumors into the Personalized OncoGenomics initiative at the British Columbia Cancer Agency whereby whole genome and transcriptome analyses of tumor/normal tissue pairs are completed with the ultimate goal of directing therapeutics. First, we established that the sequencing, analysis, and communication with oncologists could be completed in less than 5 weeks. Second, we found that cancer diagnostics is an area that can greatly benefit from the comprehensiveness of a whole genome analysis. Here, we present a scenario in which a metastasized sphenoid mass, which was initially thought of as an undifferentiated squamous cell carcinoma, was rediagnosed as an SMARCB1-negative rhabdoid tumor based on the newly acquired finding of homozygous SMARCB1 deletion. The new diagnosis led to a change in chemotherapy and a complete nodal response in the patient. This study also provides additional insight into the mutational landscape of an adult SMARCB1-negative tumor that has not been explored at a whole genome and transcriptome level.
Assuntos
Carcinoma de Células Escamosas/genética , Proteínas Cromossômicas não Histona/genética , Proteínas de Ligação a DNA/genética , Sequenciamento de Nucleotídeos em Larga Escala , Tumor Rabdoide/genética , Fatores de Transcrição/genética , Adulto , Biomarcadores Tumorais/genética , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/enzimologia , Análise Mutacional de DNA , Perfilação da Expressão Gênica , Genoma Humano , Humanos , Masculino , Tumor Rabdoide/tratamento farmacológico , Tumor Rabdoide/patologia , Proteína SMARCB1RESUMO
BACKGROUND: The impact of palliative resection of the primary tumor on outcomes in patients with metastatic colorectal cancer (mCRC) remains unclear. The primary objective of this study was to evaluate the association between palliative resection and overall survival (OS) in a population-based cohort of mCRC. METHODS: Patients diagnosed with mCRC between 2006 and 2008 and treated at the BC Cancer Agency were reviewed. Survival analysis was conducted using Kaplan-Meier methods. Cox proportional hazards regression models were fitted to evaluate the relationship between palliative resection and OS while controlling for potential confounders, such as age, gender, Eastern Cooperative Oncology Group status, carcinoembryonic antigen level, primary tumor location, metastatic site and number, and receipt of systemic therapy. To adjust for the heterogeneity and selection bias between the group that underwent palliative resection and the group that did not, a propensity score-matched analysis was also performed. RESULTS: A total of 517 patients were included. Among these cases, 378 (73 %) patients underwent palliative resection of their primary tumor, and 139 (27 %) patients did not. A total of 327 patients (63 %) were treated with palliative chemotherapy. Palliative resection was associated with a longer median OS (17.9 vs. 7.9 months) and more favorable unadjusted and adjusted hazard ratios (HRs) for death (HR 0.46, 95 % CI 0.37-0.56, p < 0.0001 and HR 0.56, 95 % CI 0.40-0.78, p = 0.0007, respectively) when compared with no resection. In a propensity score-matched analysis, prognosis was also more favorable in the resected group (p = 0.0017). CONCLUSIONS: In this cohort of mCRC patients, palliative resection of the primary tumor was associated with improved OS.
Assuntos
Neoplasias Colorretais/mortalidade , Neoplasias Colorretais/cirurgia , Cuidados Paliativos/métodos , Complicações Pós-Operatórias , Idoso , Canadá/epidemiologia , Estudos de Coortes , Neoplasias Colorretais/epidemiologia , Feminino , Seguimentos , Humanos , Masculino , Metástase Neoplásica , Estadiamento de Neoplasias , Prognóstico , Pontuação de Propensão , Taxa de SobrevidaRESUMO
PURPOSE: In metastatic colorectal cancer (mCRC), RAS mutations drive resistance to anti-epidermal growth factor receptor antibodies. It is unclear whether RAS mutations ever become clonally undetectable. METHODS: CO.26 was a phase II clinical trial that assessed durvalumab + tremelimumab in heavily pretreated mCRC. RAS mutation status was tracked over time using circulating tumor DNA (ctDNA) sequencing at baseline, week 8, and on progression. RESULTS: Among the 95 patients with KRAS/NRAS mutations in their archival tumor tissue, 6.3% (6/95) had undetectable RAS mutations in ctDNA collected at baseline or week 8 of the CO.26 study. Of these, 67% (4/6) of disappearances were transient, with the same mutation reappearing with progressive disease. In three cases, the simultaneous persistence of other preexisting CRC-associated truncal mutations could not be demonstrated, suggestive of low tumor shedding of ctDNA, leaving the incidence of true clonal reversion to RAS-wildtype (WT) possibly as low as 3.2% (3/95). Fewer patients in the neo-RAS-WT group (33%) had greater than four lesions at trial baseline compared with patients with persistent RAS mutations (75%), P = .046. The likelihood of synchronous metastases at cancer diagnosis (33% v 63%; P = .15) or liver metastases at trial baseline (50% v 68.5%; P = .17) was not significantly different between patients with disappearing versus persistent RAS mutations. Overall survival from stage IV diagnosis (hazard ratio, 0.77 [95% CI, 0.35 to 1.72]; P = .52) was not significantly different between those with disappearing versus persistent RAS mutations. The disappearance of RAS mutations was not associated with primary tumor sidedness (P = .41), archival BRAF/MEK/ERK-mutant status (P = .16/1.00/.09), nor baseline ctDNA HER2 amplifications (P = 1.00). CONCLUSION: We identified a 3.2%-6.3% prevalence of the neo-RAS-WT phenomenon in the CO.26 trial. However, 67% of apparent cases were transient with subsequent re-emergence.