A practical approach to implementing incremental haemodialysis

The majority of end-stage kidney disease patients are treated with haemodialysis (HD). Starting HD can pose physical, social, and psychological challenges to patients, and mortality rates within the first 6 months are disproportionately high, with intensive HD regimens implicated as a potential factor. Starting HD with an incremental approach, taking residual kidney function (RKF) into account, potentially allows for a gentle start with reduced dialysis intensity. Dialysis intensity (session time or frequency) can then be proportionally increased as RKF reduces. This approach to starting HD has been reported in observational studies to result in better patient self-reported health quality of life and reduced costs, and now several definitive randomised controlled trials are underway comparing an incremental approach to the conventional thrice weekly paradigm. Physician concerns over the risk of inadequate dialysis, with consequent increased emergency admissions, and practical challenges of how to estimate RKF and implement incremental dialysis have impeded widespread adoption. Addressing these challenges is paramount to increasing the uptake of incremental HD. Careful patient selection lies at the heart of a successful incremental HD programme. Generally, patients with a residual urea clearance of > 3 ml/min/1.73 m2 can be considered suitable for starting with incremental HD provided they comply with fluid intake, salt and other dietary recommendations. Calculating RKF from regular interdialytic urine collections and appropriately adjusting sessional HD clearance targets are practical and conceptual challenges. In this report we aim to disentangle these complexities and provide a step-by-step guide for patient selection and adjusting dialysis sessional targets.

Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Phase II trial of weekly erlotinib dosing to reduce duodenal polyp burden associated with familial adenomatous polyposis

IMPORTANCE

Patients with familial adenomatous polyposis (FAP) are at markedly increased risk for duodenal adenomas and cancer. Combination sulindac and erlotinib was previously shown to reduce duodenal polyp burden but was associated with a relatively high adverse event (AE) rate.

OBJECTIVE

To evaluate if a once weekly dosing schedule for erlotinib intervention improves the AE profile, while still providing efficacy with respect to reduced polyp burden, in participants with FAP.

DESIGN, SETTING AND PARTICIPANTS

Single-arm trial, enrolling 46 participants with FAP, conducted from October 2017 to September 2019 in eight academic cancer centres.

EXPOSURES

Participants self-administered 350 mg of erlotinib by mouth, one time per week for 6 months.

MAIN OUTCOMES AND MEASURES

Duodenal polyp burden (sum of polyp diameters) was assessed in the proximal duodenum by esophagogastroduodenoscopy performed at baseline and 6 months, with mean per cent change defined as the primary efficacy outcome of interest. Rate of grade 2-3 AEs was evaluated as a co-primary outcome. Secondary outcomes included changes in total duodenal polyp count, along with changes in lower gastrointestinal (GI) polyp burden and count (for participants examined by optional lower endoscopy).

RESULTS

Forty-six participants (mean age, 44.1 years (range, 18-68); women, 22 (48%)) were enrolled; 42 participants completed 6 months of intervention and were included in the per-protocol analysis. Duodenal polyp burden was significantly reduced after 6 months of weekly erlotinib intervention, with a mean per cent change of -29.6% (95% CI, -39.6% to -19.7%; p<0.0001). Similar results were observed in subgroup analyses defined by participants with advanced duodenal polyposis (Spigelman 3) at baseline (mean, -27%; 95% CI, -38.7% to -15.2%; p<0.0001). Post-intervention Spigelman stage was downstaged in 12% of the participants. Lower GI polyp number was also decreased after 6 months of intervention (median, -30.8%; IQR, -47.4% to 0.0%; p=0.0256). Grade 2 or 3 AEs were reported in 71.7% of subjects, with only two experiencing grade 3 toxicity at least possibly related to intervention.

CONCLUSION

In this single-arm, multi-centre trial of participants with FAP, erlotinib one time per week resulted in markedly lower duodenal polyp burden, and modestly reduced lower GI polyp burden, after 6 months of intervention. While AEs were still reported by nearly three-quarters of all participants, these events were generally lower grade and well-tolerated. These findings support further investigation of erlotinib as an effective, acceptable cancer preventive agent for FAP-associated GI polyposis.

TRIAL REGISTRATION NUMBER

NCT02961374.

Large-scale analysis of acquired chromosomal alterations in non-tumor samples from patients with cancer

Mosaicism, the presence of subpopulations of cells bearing somatic mutations, is associated with disease and aging and has been detected in diverse tissues, including apparently normal cells adjacent to tumors. To analyze mosaicism on a large scale, we surveyed haplotype-specific somatic copy number alterations (sCNAs) in 1,708 normal-appearing adjacent-to-tumor (NAT) tissue samples from 27 cancer sites and in 7,149 blood samples from The Cancer Genome Atlas. We find substantial variation across tissues in the rate, burden and types of sCNAs, including those spanning entire chromosome arms. We document matching sCNAs in the NAT tissue and the adjacent tumor, suggesting a shared clonal origin, as well as instances in which both NAT tissue and tumor tissue harbor a gain of the same oncogene arising in parallel from distinct parental haplotypes. These results shed light on pan-tissue mutations characteristic of field cancerization, the presence of oncogenic processes adjacent to cancer cells.

Phase II study of nab-paclitaxel in refractory small bowel adenocarcinoma and CpG island methylator phenotype (CIMP)-high colorectal cancer

Background

Hypermethylation of promoter CpG islands [CpG island methylator phenotype (CIMP)] represents a unique pathway for the development of colorectal cancer (CRC), characterized by lack of chromosomal instability and a low rate of adenomatous polyposis coli (APC) mutations, which have both been correlated with taxane resistance. Similarly, small bowel adenocarcinoma (SBA), a rare tumor, also has a low rate of APC mutations. This phase II study evaluated taxane sensitivity in SBA and CIMP-high CRC.

Patients and methods

The primary objective was Response Evaluation Criteria in Solid Tumors version 1.1 response rate. Eligibility included Eastern Cooperative Oncology Group performance status 0/1, refractory disease, and SBA or CIMP-high metastatic CRC. Nab-paclitaxel was initially administered at a dose of 260 mg/m2 every 3 weeks but was reduced to 220 mg/m2 owing to toxicity.

Results

A total of 21 patients with CIMP-high CRC and 13 with SBA were enrolled from November 2012 to October 2014. The efficacy-assessable population (patients who received at least three doses of the treatment) comprised 15 CIMP-high CRC patients and 10 SBA patients. Common grade 3 or 4 toxicities were fatigue (12%), neutropenia (9%), febrile neutropenia (9%), dehydration (6%), and thrombocytopenia (6%). No responses were seen in the CIMP-high CRC cohort and two partial responses were seen in the SBA cohort. Median progression-free survival was significantly greater in the SBA cohort than in the CIMP-high CRC cohort (3.2 months compared with 2.1 months, P = 0.03). Neither APC mutation status nor CHFR methylation status correlated with efficacy in the CIMP-high CRC cohort. In vivo testing of paclitaxel in an SBA patient-derived xenograft validated the activity of taxanes in this disease type.

Conclusion

Although preclinical studies suggested taxane sensitivity was associated with chromosomal stability and wild-type APC, we found that nab-paclitaxel was inactive in CIMP-high metastatic CRC. Nab-paclitaxel may represent a novel therapeutic option for SBA.

Anti-EGFR-resistant clones decay exponentially after progression: implications for anti-EGFR re-challenge

BACKGROUND

Colorectal cancer (CRC) has been shown to acquire RAS and EGFR ectodomain mutations as mechanisms of resistance to epidermal growth factor receptor (EGFR) inhibition (anti-EGFR). After anti-EGFR withdrawal, RAS and EGFR mutant clones lack a growth advantage relative to other clones and decay; however, the kinetics of decay remain unclear. We sought to determine the kinetics of acquired RAS/EGFR mutations after discontinuation of anti-EGFR therapy.

PATIENTS AND METHODS

We present the post-progression circulating tumor DNA (ctDNA) profiles of 135 patients with RAS/BRAF wild-type metastatic CRC treated with anti-EGFR who acquired RAS and/or EGFR mutations during therapy. Our validation cohort consisted of an external dataset of 73 patients with a ctDNA profile suggestive of prior anti-EGFR exposure and serial sampling. A separate retrospective cohort of 80 patients was used to evaluate overall response rate and progression free survival during re-challenge therapies.

RESULTS

Our analysis showed that RAS and EGFR relative mutant allele frequency decays exponentially (r2=0.93 for RAS; r2=0.94 for EGFR) with a cumulative half-life of 4.4 months. We validated our findings using an external dataset of 73 patients with a ctDNA profile suggestive of prior anti-EGFR exposure and serial sampling, confirming exponential decay with an estimated half-life of 4.3 months. A separate retrospective cohort of 80 patients showed that patients had a higher overall response rate during re-challenge therapies after increasing time intervals, as predicted by our model.

CONCLUSION

These results provide scientific support for anti-EGFR re-challenge and guide the optimal timing of re-challenge initiation.

Colorectal premalignancy is associated with consensus molecular subtypes 1 and 2

Background

Gene expression-based profiling of colorectal cancer (CRC) can be used to identify four molecularly homogeneous consensus molecular subtype (CMS) groups with unique biologic features. However, its applicability to colorectal premalignant lesions remains unknown.

Patients and methods

We assembled the largest transcriptomic premalignancy dataset by integrating different public and proprietary cohorts of adenomatous and serrated polyps from sporadic (N = 311) and hereditary (N = 78) patient populations and carried out a comprehensive analysis of carcinogenesis pathways using the CMS random forest (RF) classifier.

Results

Overall, transcriptomic subtyping of sporadic and hereditary polyps revealed CMS2 and CMS1 subgroups as the predominant molecular subtypes in premalignancy. Pathway enrichment analysis showed that adenomatous polyps from sporadic or hereditary cases (including Lynch syndrome) displayed a CMS2-like phenotype with WNT and MYC activation, whereas hyperplastic and serrated polyps with CMS1-like phenotype harbored prominent immune activation. Rare adenomas with CMS4-like phenotype showed significant enrichment for stromal signatures along with transforming growth factor-β activation. There was a strong association of CMS1-like polyps with serrated pathology, right-sided anatomic location and BRAF mutations.

Conclusions

Based on our observations made in premalignancy, we propose a model of pathway activation associated with CMS classification in colorectal carcinogenesis. Specifically, while adenomatous polyps are largely CMS2, most hyperplastic and serrated polyps are CMS1 and may transition into other CMS groups during evolution into carcinomas. Our findings shed light on the transcriptional landscape of premalignant colonic polyps and may help guide the development of future biomarkers or preventive treatments for CRC.

Utility of a molecular prescreening program in advanced colorectal cancer for enrollment on biomarker-selected clinical trials

BACKGROUND

Incorporation of multiple enrichment biomarkers into prospective clinical trials is an active area of investigation, but the factors that determine clinical trial enrollment following a molecular prescreening program have not been assessed.

PATIENTS AND METHODS

Patients with 5-fluorouracil-refractory metastatic colorectal cancer at the MD Anderson Cancer Center were offered screening in the Assessment of Targeted Therapies Against Colorectal Cancer (ATTACC) program to identify eligibility for companion phase I or II clinical trials with a therapy targeted to an aberration detected in the patient, based on testing by immunohistochemistry, targeted gene sequencing panels, and CpG island methylation phenotype assays.

RESULTS

Between August 2010 and December 2013, 484 patients were enrolled, 458 (95%) had a biomarker result, and 157 (32%) were enrolled on a clinical trial (92 on biomarker-selected and 65 on nonbiomarker selected). Of the 458 patients with a biomarker result, enrollment on biomarker-selected clinical trials was ninefold higher for predefined ATTACC-companion clinical trials as opposed to nonpredefined biomarker-selected clinical trials, 17.9% versus 2%, P < 0.001. Factors that correlated positively with trial enrollment in multivariate analysis were higher performance status, older age, lack of standard of care therapy, established patient at MD Anderson, and the presence of an eligible biomarker for an ATTACC-companion study. Early molecular screening did result in a higher rate of patients with remaining standard of care therapy enrolling on ATTACC-companion clinical trials, 45.1%, in contrast to nonpredefined clinical trials, 22.7%; odds ratio 3.1, P = 0.002.

CONCLUSIONS

Though early molecular prescreening for predefined clinical trials resulted in an increase rate of trial enrollment of nonrefractory patients, the majority of patients enrolled on clinical trials were refractory to standard of care therapy. Within molecular prescreening programs, tailoring screening for preidentified and open clinical trials, temporally linking screening to treatment and optimizing both patient and physician engagement are efforts likely to improve enrollment on biomarker-selected clinical trials.

CLINICAL TRIALS NUMBER

The study NCT number is NCT01196130.

Characterizing the patterns of clonal selection in circulating tumor DNA from patients with colorectal cancer refractory to anti-EGFR treatment

INTRODUCTION

KRAS and EGFR ectodomain-acquired mutations in patients with metastatic colorectal cancer (mCRC) have been correlated with acquired resistance to anti-EGFR monoclonal antibodies (mAbs). We investigated the frequency, co-occurrence, and distribution of acquired KRAS and EGFR mutations in patients with mCRC refractory to anti-EGFR mAbs using circulating tumor DNA (ctDNA).

PATIENTS AND METHODS

Sixty-two post-treatment plasma and 20 matching pretreatment archival tissue samples from KRAS (wt) mCRC patients refractory to anti-EGFR mAbs were evaluated by high-sensitivity emulsion polymerase chain reaction for KRAS codon 12, 13, 61, and 146 and EGFR 492 mutations.

RESULTS

Plasma analyses showed newly detectable EGFR and KRAS mutations in 5/62 [8%; 95% confidence interval (CI) 0.02-0.18] and 27/62 (44%; 95% CI 0.3-0.56) samples, respectively. KRAS codon 61 and 146 mutations were predominant (33% and 11%, respectively), and multiple EGFR and/or KRAS mutations were detected in 11/27 (41%) cases. The percentage of mutant allele reads was inversely correlated with time since last treatment with EGFR mAbs (P = 0.038). In the matching archival tissue, these mutations were detectable as low-allele-frequency clones in 35% of patients with plasma mutations after treatment with anti-EGFR mAbs and correlated with shorter progression-free survival (PFS) compared with the cases with no new mutations (3.0 versus 8.0 months, P = 0.0004).

CONCLUSION

Newly detected KRAS and/or EGFR mutations in plasma ctDNA from patients refractory to anti-EGFR treatment appear to derive from rare, pre-existing clones in the primary tumors. These rare clones were associated with shorter PFS in patients receiving anti-EGFR treatment. Multiple simultaneous mutations in KRAS and EGFR in the ctDNA and the decline in allele frequency after discontinuation of anti-EGFR therapy in a subset of patients suggest that several resistance mechanisms can co-exist and that relative clonal burdens may change over time. Monitoring treatment-induced genetic alterations by sequencing ctDNA could identify biomarkers for treatment screening in anti-EGFR-refractory patients.

Clinicopathologic characteristics and gene expression analyses of non-KRAS 12/13, RAS-mutated metastatic colorectal cancer

BACKGROUND

KRAS mutations in codons 12 and 13 are present in ∼40% of all colorectal cancers (CRC). Activating mutations in codons 61 and 146 of KRAS and in codons 12, 13, and 61 of NRAS also occur but are less frequent. The clinicopathologic features and gene expression profiles of this latter subpopulation of RAS-mutant colorectal tumors have not yet been clearly defined but in general are treated similarly to those with KRAS 12 or 13 mutations.

PATIENTS AND METHODS

Records of patients with metastatic CRC (mCRC) treated at MD Anderson Cancer Center between December 2000 and August 2012 were reviewed for RAS (KRAS or NRAS) and BRAF mutation status, clinical characteristics, and survival outcomes. To study further with an independent cohort, data from The Cancer Genome Atlas were analyzed to define a gene expression signature for patients whose tumors feature these atypical RAS mutations and explore differences with KRAS 12/13-mutated colorectal tumors.

RESULTS

Among the 484 patients reviewed, KRAS 12/13, KRAS 61/146, NRAS, and BRAF mutations were detected in 47.7%, 3.0%, 4.1%, and 7.4%, respectively, of patients who were tested for each of these aberrations. Lung metastases were more common in both the KRAS 12/13-mutated and atypical RAS-mutated cohorts relative to patients with RAS/BRAF wild-type tumors. Gene expression analyses revealed similar patterns regardless of the site of RAS mutation, and in silico functional algorithms predicted that KRAS and NRAS mutations in codons 12, 13, 61, and 146 alter the protein function and drive tumorgenesis.

CONCLUSIONS

Clinicopathologic characteristics, survival outcomes, functional impact, and gene expression profiling were similar between patients with KRAS 12/13 and those with NRAS or KRAS 61/146-mutated mCRC. These clinical and bioinformatic findings support the notion that colorectal tumors driven by these RAS mutations are phenotypically similar.

Multicenter retrospective analysis of metastatic colorectal cancer (CRC) with high-level microsatellite instability (MSI-H)

BACKGROUND

The microsatellite instability-high (MSI-H) phenotype, present in 15% of early colorectal cancer (CRC), confers good prognosis. MSI-H metastatic CRC is rare and its impact on outcomes is unknown. We describe survival outcomes and the impact of chemotherapy, metastatectomy, and BRAF V600E mutation status in the largest reported cohort of MSI-H metastatic colorectal cancer (CRC).

PATIENTS AND METHODS

A retrospective review of 55 MSI-H metastatic CRC patients from two institutions, Royal Melbourne Hospital (Australia) and The University of Texas MD Anderson Cancer Center (United States), was conducted. Statistical analyses utilized Kaplan-Meier method, Log-rank test, and Cox proportional hazards models.

RESULTS

Median age was 67 years (20-90), 58% had poor differentiation, and 45% had stage IV disease at presentation. Median overall survival (OS) from metastatic disease was 15.4 months. Thirteen patients underwent R0/R1 metastatectomies, with median OS from metastatectomy 33.8 months. Thirty-one patients received first-line systemic chemotherapy for metastatic disease with median OS from the start of chemotherapy 11.5 months. No statistically significant difference in progression-free survival or OS was seen between fluoropyrimidine, oxaliplatin, or irinotecan based chemotherapy. BRAF V600E mutation was present in 14 of 47 patients (30%). BRAF V600E patients demonstrated significantly worse median OS; 10.1 versus 17.3 months, P = 0.03. In multivariate analyses, BRAF V600E mutants had worse OS (HR 4.04; P = 0.005), while patients undergoing metastatectomy (HR 0.11; P = <0.001) and patients who initially presented as stage IV disease had improved OS (HR 0.27; P = 0.003).

CONCLUSIONS

Patients with MSI-H metastatic CRC do not appear to have improved outcomes. BRAF V600E mutation is a poor prognostic factor in MSI-H metastatic CRC.

Microsatellite instability due to hMLH1 deficiency is associated with increased cytotoxicity to irinotecan in human colorectal cancer cell lines

Around 15% of colorectal cancers (CRCs) show microsatellite instability (MSI) due to dysfunction of the mismatch repair system (MMR). As a consequence of this, MSI tumours tend to accumulate errors in mononucleotide repeats as those in genes implicated in repairing double-strand breaks (DSBs). Previous studies have shown that irinotecan (CPT-11), a chemotherapy agent inducing DSB, is more active in MSI than in microsatellite stable (MSS) CRC. The purpose of this study was to compare the sensitivity to CPT-11 in a series of CRC cell lines with either proficient or deficient MMR and to assess the mutational status of two DSB repair genes, MRE11 and RAD50, in these cell lines. hMLH1-deficient cell lines due to either epigenetic silencing or mutation showed very similar IC(50) and were four- to nine-fold more sensitive to CPT-11 than the MSS line. Cell lines harbouring mutations in both MRE11 and RAD50 were most sensitive to CPT-11. We conclude that MSI cell lines display higher sensitivity to CPT-11 than MSS cells. Mutation of MRE11 and RAD50 could account for this difference in response to CPT-11. Future clinical trials tailoring chemotherapy regimens based on microsatellite status are warranted.

New drug development in digestive neuroendocrine tumors

The traditional cytotoxic agents are of limited efficacy in the treatment of neuroendocrine tumors of the gastrointestinal tract (NETs). Recent investigations have brought up a number of biological features in this family of neoplasms that could represent targets for anticancer treatment. NETs seem to have an extraordinary tumor vascularization with high expression of proangiogenic molecules such as the vascular endothelial growth factor along with overexpression of certain tyrosine kinase receptors such as the epidermal growth factor receptor (EGFR), the insulin growth factor receptor (IGFR) and their downstream signaling pathway components (PI3K-AKT-mTOR). The rationale of an antiangiogenic approach in the treatment of NETs and the use of other pharmacological strategies such as EGFR, IGFR and mammalian target of rapamycin inhibitors are discussed. Additionally, the emerging results of recent clinical trials with these targeted drugs are presented.

Microsatellite instability (MSI) due to mutation or epigenetic silencing is associated with increased cytotoxicity to irinotecan (CPT-11) in human colorectal cancer (CRC) cell lines

10527

Background: MSI is a phenomenon found in tumor DNA of individuals with dysfunction of the mismatch repair system (MMR). Epigenetic inactivation by promoter hypermethylation of hMLH1 causes 15 to 20% of sporadic CRC. In vitro studies have suggested an increased sensitivity to CPT-11 of MMR-deficient human CRC cell lines. Chemosensitivity evaluation in preclinical models of human CRC cell lines according to the MMR status could help in the design of specific studies in the clinical setting. Methods: We have performed drug cytotoxicity assays to compare sensitivity to CPT-11 in several human CRC cell lines with different MMR gene status that resemble the most common clinical situations in CRC patients. HCT116, HCT15, SW48 and RKO are MSI-High (MSI-H), being HCT116 due to a homozygous nonsense mutation of hMLH1 gene, HCT15 due to MSH6 mutation (both of them similar to hereditary cases) and both SW48 and RKO due to methylation of hMLH1 promoter (as MSI-H sporadic CRC cases). HT29 expresses normal levels of MMR proteins (as microsatellite stable (MSS) CRC cases). Drug concentrations resulting in 50% growth inhibition (IC50) were determined by a curve-fitting analysis and cell cycle analyses in order to characterize the cytotoxicity of cell lines were performed. Results: IC50 values and 95% confidence intervals (CI) are show in Table 1 . hMLH1-deficient cell lines due to either epigenetic silencing or mutation showed very similar IC50 and were 5- to 8-fold more sensitive to CPT-11 than the MSS line. hMSH6- deficient cell line HCT15 has sensitivity closer to MSS than MSI cell lines. Treatment with CPT-11 induced a G2/M arrest. Conclusions: Lack of hMLH1 protein due to either genetic alteration or epigenetic silencing correlates with increased sensitivity to CPT-11. MSI-H CRC cell lines are more sensitive to CPT-11 than MSS. Future clinical trials tailoring chemotherapy regimens based on microsatellite status are warranted.

[Table: see text]

No significant financial relationships to disclose.

Phase I study of bi-weekly pemetrexed (P) plus cisplatin (C) in patients with advanced cancer

2580

Background: Cisplatin and pemetrexed have demonstrated clinical activity in several malignant tumors including mesothelioma and non small cell lung cancer. There is preclinical evidence of synergism between both agents as well as clinical non-overlapping toxicities, thus providing the rationale for their evaluation in combination. Our aim was to develop a well-tolerated combination of bi-weekly CP able to deliver higher dose intensity than the every 3-week standard. Methods: Escalating doses of P from a starting dose level of 300 mg/m2, with a fixed-dose of C 50 mg/m2, both biweekly on 28-day cycles, were administered to patients with refractory advanced solid malignancies and calculated creatinine clearance = 45 mL/min. Results: Twenty one patients (5 female/16 male); median age 61 (39–76); ECOG 0 (16), 1 (5); lung cancer (9); soft-tissue sarcoma (3); unknown primary, bladder, breast, rectum, esophagus, melanoma, mesothelioma, prostate, and tonsil (1, each) have received a total of 48 courses (median 2, range 0–5), at P dose levels of 300 mg/m2 [8 pts, Dose level 1 (DL1)], 400 mg/m2 (7 pts, DL2), and 500 mg/m2 (6 pts, DL3), with full doses of C. Four patients were non-evaluable (2 at DL1, 1 at DL2 and 1 at DL3) because of early PD (2) and non-drug related serious adverse event (2 pt). Dose Limiting Toxicities (DLT) were G4 neutropenia (1 pt) at 300 mg/m2; and prolonged G 1/2 thrombocytopenia (1 pt) at 500 mg/m2. There were also 2 pts with non-DLT G4 neutropenia at DL3. The rest of toxicities were mild to moderate being the most frequent asthenia, nausea, anorexia, stomatatis, and sensory neuropathy. DL3 was considered the Maximum Tolerated Dose (MTD) and the previous level with P at 400 mg/m2 was declared the recommended phase II dose. Three additional patients were treated at DL2 for dose confirmation. A PR has been observed in 2 pts with NSCLC, 1 pt with breast, and 1 with esophagus cancer. Conclusions: Biweekly administration of pemetrexed (400 mg/m2) plus cisplatin (50 mg/m2) is clinically well tolerated and can be used safely. The regimen delivers higher dose intensity of P and equal of C as the standard. This regimen is currently being studied in a phase 2 trial in patients with locally advanced, non resectable or metastatic urothelial cancer.

No significant financial relationships to disclose.

Patterns of care and outcome of patients with gastroenteropancreatic neuroendocrine tumors (GNETs): Results from a Spanish multi-center hospital-based tumor registry

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Background: GNET represent an unusual family of neoplasms with a wide and complex spectrum of clinical behavior. To provide information regarding demographic characteristics, diagnostic procedures, tumor features, therapeutic interventions and outcomes of pts with GNETs, a national tumor registry was launched. We present here the results of this broad-based multi-institutional observational registry that comprises 41 sites representing all regions of Spain. Methods: Data was provided at www.retegep.net by participating centers and assessed for internal consistency by external independent reviewers. Results: The study cohort comprised 474 pts (57% male, median age: 59 years). 52% were carcinoids (C), 18% non-functioning pancreatic tumors (PT), 9% insulinomas and 6% gastrinomas. Most common primary tumor sites included midgut (19%), and head (14%) and body of the pancreas (9%). 10% were of unknown primary. Functioning symptoms led to diagnosis in 29% of cases. 5% were associated to MEN1. Diagnostic workup included serum hormone tests (60%), ultrasound (40%), CT scan (75%) and octreoscan (37%). 32% of pts presented with localized tumors (L), 14% with local-regional spread (LR) and 44% with advanced disease (Adv). Treatment for Adv disease consisted of somatostatin analogues (SA) (48%), surgery (45%), chemotherapy (CT) (42%), interferon (IFN) (23%), chemoembolization (9%) and radiofrequency ablation (5%). 5-year survival (5yS) for the whole group was 61.1% (SD:3.4%), 78.2% (SD:5.4%) for pts with L/LR disease and 47.1% (SD:5.6%) for Adv stages. 5yS rates were similar for C and PT tumors, also when stratifying according to tumor stage (84 and 76% for local-regional disease, and 51 and 49% for Adv disease). 1st line systemic therapy (n=175) consisted of CT (42%), SA (39%), IFN (5%), SA+IFN (10%) and SA+CT (3%), with 5yS rates of 59%, 36%, 42%, 46% and 38%, respectively (p=0.7). As second line systemic treatment (n=65) 45% received CT, 26% SA, 15% immunotherapy and 14% different drug combinations. Conclusions: This national database reveals relevant information regarding current Spanish practices and will provide valuable insights into the epidemiology and management of this heterogeneous uncommon disease

No significant financial relationships to disclose.

Molecular biology of testicular germ cell tumors

Testicular germ cell tumors (TCGT) comprise a heterogeneous group of neoplasms, although all of them are originated from common precursors related to germ cell lineage. Understanding of normal development of germinal cells is essential to define new markers for diagnosis, prognostic subgroups and targeted therapies. Recent advances related to cytogenetic and molecular features have established the role of immunohistochemistry of c-kit, OCT-3/4 and determination of gain of chromosome 12 in the daily workup of premalignant lesions and invasive tumors. This review summarizes the current knowledge in the field of molecular biology of TGCT.

Feasibility of pegfilgrastim as haematopoietic support for dose-dense every-2-week adjuvant chemotherapy in breast cancer

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Background: Dose-dense sequential chemotherapy has been safety supported with Filgrastim (F). Pegfilgrastim (PEGF) is a pegylated recombinant human granulocyte colony-stimulating factor (G-CSF) that has a long half-life, a fact that facilitates a less frequent dosing. Its safety and efficacy has been established in 21- and 28-days schedules. Methods: We have performed a retrospective analysis of medical records of 2 cohort of patients (n=38) treated at our institution between December 2003 and November 2005. All patients received Adriamicin 60 mg/m2 plus Ciclophosphamide 600 mg/m2 q2w for 4 cycles followed by Paclitaxel 175 mg/m2 q2w for 4 cycles. As G-CSF support, in Cohort A (n=29) PEGF was administered 6 mg on day 2 of each cycle and in Cohort B (n=9) F days 3 to 10 at 5 μg/kg. The primary end point was to explore the feasibility and safety in terms of febrile neutropenia (FN) events, number of treatment delays (TD), incidence of neutropenia grade 3 (NPG3) and 4 (NPG4) and mean absolute neutrophil count (ANC) on day 14 of cycle 1 to 7 for both groups. Indirect comparisons have been performed. Results: Patients characteristics in both cohorts were well balanced, except for age in cohort A compared with cohort B (44,89 versus 52,5, p = 0,02). FN events and TD were increased in cohort B compared with cohort A (22% versus 0%, p=0.051, both comparisons). No statistically significant difference in number of episodes of NPG3 and NPG4 was observed. Median ANC on day 14 for each treatment cycle was significantly greater for Cohort A than Cohort B, except for cycle 6. Conclusions: PEGF is very safe and efficacy in patients treated with dose-dense sequential adjuvant chemotherapy for breast cancer. It could be even more efficient than F in preventing febrile neutropenia events.

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Pegfilgrastim induces elevation of serum CA 15–3 in breast carcinoma patients after receiving dose-dense adjuvant chemotherapy

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Background: CA 15–3, an epytope related with MUC-1 gene products, is a well known tumour marker to predict early recurrent disease breast cancer. MUC-1 expression can be detected in neutrophil membrane and cytoplasm. It is known that patients with breast cancer who receive adjuvant chemotherapy with G-CSF support may show CA 15–3 false positive elevations Methods: We identified by medical records 76 patients who received adjuvant sequential chemotherapy for breast cancer consisted in Doxorubicin/Ciclophosphamide for 4 cycles followed by Paclitaxel for 4 cycles every-2 (with haematopoietic support with Pegfilgrastim (Cohort A, n=29) or Filgrastim (Cohort B, n=10)) and every-3-weeks without haematopoietic support (cohort C, n=37) between October 2003 and November 2005. Mean values of CA 15–3 recorded at the first follow up (FU) visit after treatment and number of patients with levels above the cut-off value of 40 U/mL were compared between the three patients cohorts. Correlation between CA 15–3 with alkaline phosphatase (AP) levels measured at first FU and with absolute neutrophil count (ANC) mean values measured on day 14 of every cycle were performed for each cohort Results: Patients characteristics between cohorts were well balanced except for age. A statistically significantly difference in median CA 15–3 post-treatment values were observed between Cohort A and C (34.01 versus 22.3, p=0.001), but no between Cohort A and B (34.01 versus 30.53). Eight patients in Cohort A, 2 in B and 1 in C had CA 15–3 levels above 40 UI/mL (27.6% versus 20% versus 2.7%, p=0.009). CA 15–3 decreased to normal values at subsequent visits. CA 15–3, mean ANC (r= 0.272, p= 0.020), and AP (r= 0.361, p= 0.002) were found associated each other when the whole database was analyzed Conclusions: These data provide evidence that Pegfilgrastim induces elevation of CA 15–3 level in comparison with patients treated without G-CSF support. This elevation may be related to the increased neutrophil counts. Physicians should be aware of this fact during the follow up to avoid unnecessary diagnostic workup.

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Influence of first line treatment in the 5 (5yS) and 10-year (10yS) survival outcomes of patients with gastroenteropancreatic neuroendocrine tumors (GNETs): 2001–2005 Spanish task force GNET group

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Background: Data on incidence, morbidity and mortality of GNETs is limited due to the low frequency of these tumors. However this survival data is critical to design studies with new agents. Methods: Data was obtained from medical records of 262 patients with GNETs and centralized in an online registry at www.retegep.net . Among the study parameters were histology, localization, stage, diagnostic workup, 1st line and subsequent treatments, 5yS and 10yS for the whole dataset and for different stages, tumor types and 1st line systemic treatment. Results: Mean age 58, 58% male. Primary tumors: 49% Carcinoids (C), 19% non-functioning pancreatic tumors (PT), 9% insulinomas, 6% gastrinomas and 8% unknown primary. Localizations: midgut (36%), head (17%) and body of pancreas (10%). Functioning symptoms led to diagnosis in 38% of cases. 4% were associated to MEN1. Stage at diagnosis was advanced (Adv) in 46%, localised (L) in 30% and locorregional (LR) in 13% (unknown in 11%). Diagnostic workup were CT Scan (84%), Octreoscan (52%) and US (52%) and serum hormone tests (65%). Treatments for Adv disease included somatostatin analogues (SA) (47%), surgery (S) (43%), chemotherapy (CT) (35%) and interferon (IFN) (34%), embolization (7%) and radiofrequency ablation (3%). 5yS and 10yS for the whole group was 61.6% (SD: 5.2%) and 49.8% (SD: 7.7%) respectively. 5yS and 10yS for the L/LR and Adv stages were 78.1% (SD: 7.3%) and 71% (SD: 10%), and 48.9% (SD: 7.7%) and 29% (SD: 12.4%), respectively. LR PT and C had similar 5 and 10yS but Adv PT did worse than Adv C (5yS of 36.2% and 61.1%, respectively). 1st line systemic treatment for LR and Adv disease (n=90) included SA (39%), CT (34.4%), IFN (5.6%), combinations of SA+IFN (13.3%), A+CT (4.4%) and other combinations (3.3%), with a 10yS rate of 69%, 79%, 50%, 89%, 66% and 50%, respectively. Adv PT perform worse than C regardless of treatment choice. As second line systemic treatment (n=43) 30% received SA, 30% CT, 26% inmunotherapy and 14% combinations. Conclusions: An extensive use of systemic therapy and a scarce use of non-surgical LR treatments is observed in the Adv stages. Choice of 1st line systemic treatment does not seem to influence survival outcomes.

No significant financial relationships to disclose.

A comparative analysis of three different dose combinations of oral contraceptives

Three different low-dose formulations of oral contraceptives were compared to determine the most suitable preparation for Filipino women as reflected in the first year continuation rates, incidence of side effects and failure rates. A total of 1,800 subjects were enrolled in the study from 18 health centers in six provinces in two regions of the Philippines, covering a total of 18,282 women-months of use. Sociodemographic characteristics were comparable. The monophasic levonorgestrel group showed the best performance followed by the triphasic preparation. The norethindrone group consistently showed higher drop-out rates, which may be due to the relatively higher incidence of side effects. For all three preparations, bleeding irregularities were low. There were no major side effects and no pregnancy was reported in one year of use. Noted was a distinct regional and provincial difference in recruitment and follow-up performance, possibly due to clinic, client or program factors.