RAS testing of liquid biopsy correlates with the outcome of metastatic colorectal cancer patients treated with first-line FOLFIRI plus cetuximab in the CAPRI-GOIM trial.

Background: Liquid biopsy is an alternative to tissue for RAS testing in metastatic colorectal carcinoma (mCRC) patients. Little information is available on the predictive role of liquid biopsy RAS testing in patients treated with first-line anti-EGFR monoclonal antibody-based therapy. Patients and methods: In the CAPRI-GOIM trial, 340 KRAS exon-2 wild-type mCRC patients received first-line cetuximab plus FOLFIRI. Tumor samples were retrospectively assessed by next generation sequencing (NGS). Baseline plasma samples were analyzed for KRAS and NRAS mutations using beads, emulsion, amplification, and magnetics digital PCR (BEAMing). Discordant cases were solved by droplet digital PCR (ddPCR) or deep-sequencing. Results: A subgroup of 92 patients with available both NGS data on tumor samples and baseline plasma samples were included in this study. Both NGS analysis of tumor tissue and plasma testing with BEAMing identified RAS mutations in 33/92 patients (35.9%). However, 10 cases were RAS tissue mutant and plasma wild-type, and additional 10 cases were tissue wild-type and plasma mutant, resulting in a concordance rate of 78.3%. Analysis of plasma samples with ddPCR detected RAS mutations in 2/10 tissue mutant, plasma wild-type patients. In contrast, in all tissue wild-type and plasma mutant cases, ddPCR or deep-sequencing analysis of tumor tissue confirmed the presence of RAS mutations at allelic frequencies ranging between 0.15% and 1.15%. The median progression-free survival of RAS mutant and wild-type patients according to tissue (7.9 versus 12.6 months; P = 0.004) and liquid biopsy testing (7.8 versus 13.8 moths; P < 0.001) were comparable. Similar findings were observed for the median overall survival of RAS mutant and wild-type patients based on tissue (22.1 versus 35.8 months; P = 0.016) and plasma (19.9 versus 35.8 months; P = 0.013) analysis. Conclusion: This study indicates that RAS testing of liquid biopsy results in a similar outcome when compared with tissue testing in mCRC patients receiving first-line anti-EGFR monoclonal antibodies.

Cetuximab continuation after first progression in metastatic colorectal cancer (CAPRI-GOIM): a randomized phase II trial of FOLFOX plus cetuximab versus FOLFOX.

BACKGROUND: Cetuximab plus chemotherapy is a first-line treatment option in metastatic KRAS and NRAS wild-type colorectal cancer (CRC) patients. No data are currently available on continuing anti-epidermal growth factor receptor (EGFR) therapy beyond progression. PATIENTS AND METHODS: We did this open-label, 1:1 randomized phase II trial at 25 hospitals in Italy to evaluate the efficacy of cetuximab plus 5-fluorouracil, folinic acid and oxaliplatin (FOLFOX) as second-line treatment of KRAS exon 2 wild-type metastatic CRC patients treated in first line with 5-fluorouracil, folinic acid and irinotecan (FOLFIRI) plus cetuximab. Patients received FOLFOX plus cetuximab (arm A) or FOLFOX (arm B). Primary end point was progression-free survival (PFS). Tumour tissues were assessed by next-generation sequencing (NGS). This report is the final analysis. RESULTS: Between 1 February 2010 and 28 September 2014, 153 patients were randomized (74 in arm A and 79 in arm B). Median PFS was 6.4 [95% confidence interval (CI) 4.7-8.0] versus 4.5 months (95% CI 3.3-5.7); [hazard ratio (HR), 0.81; 95% CI 0.58-1.12; P = 0.19], respectively. NGS was performed in 117/153 (76.5%) cases; 66/117 patients (34 in arm A and 32 in arm B) had KRAS, NRAS, BRAF and PIK3CA wild-type tumours. For these patients, PFS was longer in the FOLFOX plus cetuximab arm [median 6.9 (95% CI 5.5-8.2) versus 5.3 months (95% CI 3.7-6.9); HR, 0.56 (95% CI 0.33-0.94); P = 0.025]. There was a trend in better overall survival: median 23.7 [(95% CI 19.4-28.0) versus 19.8 months (95% CI 14.9-24.7); HR, 0.57 (95% CI 0.32-1.02); P = 0.056]. CONCLUSIONS: Continuing cetuximab treatment in combination with chemotherapy is of potential therapeutic efficacy in molecularly selected patients and should be validated in randomized phase III trials.

Heterogeneity of KRAS, NRAS, BRAF and PIK3CA mutations in metastatic colorectal cancer and potential effects on therapy in the CAPRI GOIM trial.

BACKGROUND: Evidence suggests that metastatic colorectal carcinoma (mCRC) has a high level of intratumor heterogeneity. We carried out a quantitative assessment of tumor heterogeneity for KRAS, NRAS, BRAF and PIK3CA mutations, in order to assess potential clinical implications. PATIENTS AND METHODS: Tumor samples (n = 182) from the CAPRI-GOIM trial of first-line cetuximab + FOLFIRI in KRAS exon-2 wild-type mCRC patients were assessed by next-generation sequencing that allows quantitative assessment of mutant genes. Mutant allelic frequency was normalized for the neoplastic cell content and, assuming that somatic mutations usually affect one allele, the Heterogeneity Score (HS) was calculated by multiplying by 2 the frequency of mutant alleles in neoplastic cells. Therefore, HS virtually corresponds to the fraction of neoplastic cells carrying a specific mutation. RESULTS: The KRAS HS ranged between 12 and 260 with mean value of 87.1 and median value of 84.4, suggesting that in most CRC, the majority of neoplastic cells carry mutant KRAS. Similar findings were observed for NRAS (HS range 35.5-146.7; mean 102.8; median 117.1). In contrast, in BRAF (HS range 17.1-120; mean 54.8; median 54.3) and PIK3CA (HS range 14.3-120; mean 59.5; median 47.3) mutant cases, only a fraction of neoplastic cells seem to carry the mutant allele. The response rate was 70% in KRAS mutant patients with an HS <33 (low KRAS; n = 10) and 45.7% in KRAS HS >33 patients (high KRAS; n = 35); median progression-free survival were 7.97 and 8.37 months, respectively. Low-KRAS tumors had a higher frequency of additional mutations in PIK3CA when compared with high-KRAS (6/10 versus 8/35). CONCLUSIONS: KRAS and NRAS mutations are usually present in the majority of neoplastic cells, whereas BRAF and PIK3CA mutations often affect a limited fraction of transformed cells. Resistance to cetuximab in low-KRAS patients might be driven by the complex mutational profile rather than KRAS mutation load.

Clinical activity of FOLFIRI plus cetuximab according to extended gene mutation status by next-generation sequencing: findings from the CAPRI-GOIM trial.

BACKGROUND: Treatment with antiepidermal growth factor receptor (anti-EGFR) monoclonal antibodies has been restricted to metastatic colorectal cancer (mCRC) patients with RAS wild-type tumors. Next-generation sequencing (NGS) allows the assessment in a single analysis of a large number of gene alterations and might provide important predictive and prognostic information. PATIENTS AND METHODS: In the CAPRI-GOIM trial, 340 KRAS exon 2 wild-type mCRC patients received first-line FOLFIRI plus cetuximab. Tumor samples (182/340, 53.5%) were assessed by NGS to search for mutations in 22 genes involved in colon cancer. RESULTS: Objective responses in the NGS cohort were observed in 104/182 patients [overall response rate (ORR) 57.1%; 95% confidence interval (95% CI) 52% to 66.4%] with a median progression-free survival (mPFS) of 9.8 (95% CI 8.7-11.5) months. NGS analysis was successfully completed in all 182 samples. One or more gene mutations (up to five) were detected in 124/182 (68.1%) tumors within 14/22 genes for a total of 206 mutations. KRAS exon 2 mutations were identified in 29/182 (15.9%) samples, defined as wild type by local laboratory assessment. Frequently mutated genes were: TP53 (39.6%), KRAS exons 3/4 (8.8%), NRAS exons 2/3 (7.1%), PIK3CA exons 9/20 (13.2%), BRAF (8.2%). FOLFIRI plus cetuximab treatment determined ORR of 62.0% (95% CI 55.5% to 74.6%) with mPFS of 11.1 (95% CI 9.2-12.8) months in patients with KRAS and NRAS wild-type tumors. Conversely, ORR was 46.6% (95% CI 39.9-57.5%) with mPFS of 8.9 (95% CI 7.4-9.6) months in patients with KRAS or NRAS mutations. Similarly, the subgroup of patients carrying KRAS, NRAS, BRAF, or PIK3CA mutations showed a worse outcome, although this might be due to a prognostic effect. CONCLUSIONS: This study demonstrates that NGS analysis in mCRC is feasible, reveals high level of intra and intertumor heterogeneity, and identifies patients that might benefit of FOLFIRI plus cetuximab treatment.

Clinical activity and tolerability of FOLFIRI and cetuximab in elderly patients with metastatic colorectal cancer in the CAPRI-GOIM first-line trial.

BACKGROUND: In the cetuximab after progression in KRAS wild-type colorectal cancer patients (CAPRI) trial patients with metastatic colorectal cancer (mCRC) received 5-fluorouracil, folinic acid and irinotecan (FOLFIRI) and cetuximab in first line followed by 5-Fluorouracil, folinic acid, oxaliplatin (FOLFOX) with or without cetuximab until progression. Limited data are available on the efficacy and safety of anti-epidermal growth factor receptor (anti-EGFR) agents on elderly patients with mCRC. In the current study we evaluated the efficacy and safety of FOLFIRI plus cetuximab in age-defined subgroups. METHODS: A post-hoc analysis was performed in CAPRI trial patients; outcomes (progression-free survival (PFS), overall response rate (ORR), safety) were analysed by age-groups and stratified according to molecular characterisation. 3 age cut-offs were used to define the elderly population (≥65; ≥70 and ≥75 years). RESULTS: 340 patients with mCRC were treated in first line with FOLFIRI plus cetuximab. Among those, 154 patients were >65 years, 86 >70 years and 35 >75 years. Next-generation sequencing (NGS) was performed in 182 patients. Among them, 87 patients were >65 years, 46 >70 and 17 >75. 104 of 182 patients were wild type (WT) for KRAS, NRAS, BRAF, PIK3CA genes. In the quadruple WT group, 51 patients were ≥65 years; 29 were ≥70; 9 were ≥75. Median PFS was similar within the age-subgroups in the intention-to-treat population, NGS cohort and quadruple WT patients, respectively. Likewise, ORR was not significantly different among age-subgroups in the 3 populations. Safety profile was acceptable and similarly reported among all age-groups, with the exception of grade ≥3 diarrhoea (55% vs 25%, p=0.04) and neutropaenia (75% vs 37%, p=0.03) in patients ≥75 years and grade ≥3 fatigue (31% vs 20%, p=0.01) in patients <75 years. CONCLUSIONS: Tolerability of cetuximab plus FOLFIRI was acceptable in elderly patients. Similar ORR and PFS were observed according to age-groups. No differences in adverse events were reported among the defined subgroups with the exception of higher incidence of grade ≥3 diarrhoea and neutropaenia in patients ≥75 years and grade ≥3 fatigue in patients <75 years. TRIAL REGISTRATION NUMBER: 2009-014041-81.

Structure-activity studies of the Phe(4) residue of nociceptin(1-13)-NH(2): identification of highly potent agonists of the nociceptin/orphanin FQ receptor.

A total of 32 compounds was prepared to investigate the functional role of Phe(4) in NC(1-13)-NH(2), the minimal sequence maintaining the same activity as the natural peptide nociceptin. These compounds could be divided into three series in which Phe(4) was replaced with residues that would (i) alter aromaticity or side chain length, (ii) introduce steric constraint, and (iii) modify the phenyl ring. Compounds were tested for biological activity as (a) inhibitors of the electrically stimulated contraction of the mouse vas deferens; (b) competitors of the binding of [(3)H]-NC-NH(2) to mouse brain membranes; and (c) inhibitors of forskolin-stimulated cAMP accumulation in CHO cells expressing the recombinant human OP(4) receptor. Results indicate that all compounds of the first and second series were inactive or very weak with the exception of [N(CH(3))Phe(4)]NC(1-13)-NH(2), which was only 3-fold less potent than NC(1-13)-NH(2). Compounds of the third series showed higher, equal, or lower potencies than NC(1-13)-NH(2). In particular, [(pF)Phe(4)]NC(1-13)-NH(2) (pF) and [(pNO(2))Phe(4)]NC(1-13)-NH(2) (pNO(2)) were more active than NC(1-13)-NH(2) by a factor of 5. In the mVD, these compounds showed the following order of potency: (pF) = (pNO(2)) > or = (pCN) > (pCl) > (pBr) > (pI) = (pCF(3)) = (pOCH(3)) > (pCH(3)) > (pNH(2)) = (pOH). (oF) and especially (mF) maintained high potencies but were less active than (pF). Similar orders of potency were observed in binding competition and cAMP accumulation studies. There was a strong (r(2) > or = 0.66) correlation between data observed in these assays. Biological activity data of compounds of the third series were plotted against some Hansch parameters that are currently used to quantify physicochemical features of the substituents. In the three biological assays agonist potency/affinity positively correlates with the electron withdrawal properties of the groups in the p-position of Phe(4) and inversely with their size.

Structure-activity relationships of nociceptin and related peptides: comparison with dynorphin A.

Nociceptin and its receptor (OP(4)) share sequence homologies with the opioid peptide ligand dynorphin A and its receptor OP(2). Cationic residues in the C-terminal sequence of both peptides seem to be required for selective receptor occupation, but the number and the distribution of these basic residues are different and quite critical. Both receptors are presumably activated by the peptides N-terminal sequence (Xaa-Gly Gly-Phe, where Xaa = Phe or Tyr); however, although OP(4) requires Phe(4) as a determinant pharmacophore, OP(2) requires Tyr(1) as do the other opioid receptors. An extensive structure-activity analysis of the N-terminal tetrapeptide has led to conclude that the presence of aromatic residues in position one and four, preferably Phe, as well as the distance between Phe(1) and Phe(4) are extremely critical for occupation and activation of OP(4) in contrast with other opioid receptors (e.g. OP(1), OP(3), OP(2)). Modification of distance between the side chains of Phe(1) and Phe(4) (as obtained with Nphe(1) substitution in both NC and NC(1-13)-NH(2)) and/or conformational orientation of Phe(1) (as in Phe(1)psi(CH(2)-NH)-Gly(2)) has brought to discovery of pure antagonist ([Nphe(1)]-NC(1-13)-NH(2)) and a partial agonist ([Phe(1) psi(CH(2)-NH)-Gly(2)]-NC(1-13)-NH(2)), which have allowed us to characterize and classify the OP(4) receptor in several species. Thus, although antagonist activities at the OP(4) receptor are obtained by chemical modification of Phe(1)-Gly(2) peptide bond or by a shift of Phe(1) side chain of NC peptides, antagonism at the OP(2) receptor requires the diallylation of the N-terminal amino function, for instance, of dynorphin A. These considerations support the interpretation that the two systems nociceptin/OP(4) and dynorphin A/OP(2) are distinct pharmacological entities that differs in both their active sites (Tyr(1) for Dyn A and Phe(4) for NC) and the number and position of cationic residues in the C-terminal portions of the molecules. The chemical features of novel OP(4) receptor ligands either pseudopeptides obtained by combinatorial library screening or molecules of nonpeptide structure are reported and discussed in comparison with NC and NC related peptides.

Effects of Ro 64-6198 in nociceptin/orphanin FQ-sensitive isolated tissues.

The pharmacological profile of the non-peptide OP4 receptor (ORL1, LC132) agonist, Ro 64-6198, was investigated, in three electrically stimulated nociceptin/orphanin FQ (NC)-sensitive preparations, namely the mouse and rat vas deferens and the guinea pig ileum. Ro 64-6198 mimicked the inhibitory effect of NC in the three preparations, while showing slow kinetics of action and a slowly reversible effect compared to the fast and immediately and completely reversible effect of the natural peptide. Ro 64-6198 displayed similar pEC50 and Emax values as NC in the mouse and rat vas deferens while it was 100-fold less potent but more efficacious (higher Emax) than NC in the guinea pig ileum. In the rat vas deferens the effects of Ro 64-6198 were antagonised by [Nphe1]NC(1-13)NH2 and J-113397 with pKB values (6.30 and 8.05, respectively) similar to those obtained against NC (6.20 and 7.77, respectively). Naloxone (1 microM) was inactive. In the guinea pig ileum a clear shift of the concentration response curve to Ro 64-6198 was obtained only using a cocktail of antagonists (naloxone + [Nphe1]NC(1-13)NH2 or naloxone + J-113397). In the mouse vas deferens the antagonists were inactive against Ro 64-6198 either when tested alone or in combination. Therefore, Ro 64-6198 behaved as a selective OP4 receptor agonist only in the rat tissue. These results suggest a physiological heterogeneity in OP4 receptors across tissues and species and may explain why, when tested in vivo, Ro 64-6198 mimics the potent anxiolytic effect of NC better in the rat than in the mouse.

In vitro pharmacological profile of peptide III-BTD: a novel ligand for nociceptin/orphanin FQ and opioid receptors.

Peptide III-BTD has been recently identified as a non-selective nociceptin/orphanin FQ receptor ligand by screening of a synthetic peptide combinatorial library. In the present study we evaluated the pharmacological profile of peptide III-BTD in isolated tissues (mouse and rat vas deferens, guinea pig ileum) sensitive to both nociceptin and opioid peptides. In the mouse vas deferens and guinea pig ileum, III-BTD concentration dependently inhibited the electrically induced twitch (pEC50 5.91 and 6.18, respectively; Emax 94 +/- 1% and 94 +/- 2%) and this effect was blocked by naloxone (1 microM). In the rat vas deferens, III-BTD was inactive in most of the tissues, while in few others it elicited a slight inhibition only at the highest concentration tested (10 microM). In the presence of 1 microM naloxone, 1 microM III-BTD shifted to the right the concentration response curve of nociceptin in a parallel manner, showing pKB values in the range 6.6-6.9. These data confirm on native nociceptin receptors the pharmacological profile of peptide III-BTD which behaved as a mixed nociceptin receptor antagonist/opioid receptor agonist in the [35S]GTPyS binding assay performed on cells expressing the recombinant human receptors.

[Myoglobinuria secondary to hypokalemia during prolonged diuretic therapy]. / Mioglobinuria secondaria ad ipopotassiemia in corso di terapia diuretica protratta.

Myoglobinuria secondary to hypopotassemia was noted in a hypertensive patient treated for a long period with diuretics (chlorthalidone and indapamide). The picture included hypokalemic myopathy, with myoglobinuria, an increase in serum enzymes related by rhabdomyolysis, and flaccid paralysis. In spite of reinstatement management with potassium chloride, hypopotassemia promoted a torsade de pointes, quickly followed by terminal ventricular fibrillation.

[Causes of death in patients with cerebral neoplasms]. / Dødsårsagen ved neoplasma cerebri.

The case records of 41 patients with cerebral cancer and their death certificates were reviewed with the object of investigating clinicians' causal reasoning. No really clear impression could be obtained. The case records did not contain any reflections about clinical or paraclinical conditions which might be related to conceptions of causality. The death certificates contained errors and deficits which were so serious in 44% of the cases that the death certificate presented an erroneous picture of the cause or causes of death. Minor errors were encountered in further 19% of the death certificates. These involved logically untenable statements of causes in 11 certificates (27%), statements about conditions which were not in agreement with the reports in 13 cases (32%) and errors in the statements about duration in ten cases (24%). These results scarcely express doctors' causal reasoning but rather that there is no uniform conception of how death certificates should be completed.

[Medical diagnosis]. / Medicinsk diagnostik.

The diagnostic process holds a firm position in medical practice, but is often claimed to be part of the "art of medicine", partially beyond reach of rational and logical analysis. Research in clinical cognition, decision analysis and artificial intelligence have, however, elucidated essential parts of medical diagnosis. A characteristic feature of diagnosis is the manner in which uncertainties are handled. Early generation of hypotheses about the nature of the condition present seems to be useful method. Similarly, probabilistic, causal and deterministic reasoning can be illustrated by diagnostic models which have found favor during recent years. A certain type of cognitive process (heuristic) is employed when assessing information of probabilistic nature. The diagnostic models are partial and concern the parts of the process, which may be represented verbally and consciously. This raises the question of how the clinician actually draws upon experience (background knowledge), which preconditions shape the generation of applicable diagnostic hypotheses and how the diagnostic capability of the individual physician can be facilitated.

[Classification of diseases--is a systematic approach only possible at the expense of applicability?]. / Klassifikation af sygdomme--kan systematik kun opnås på bekostning af anvendelighed?

Classification of diseases is a practical tool in clinical and scientific medicine, but it is not free of problems. Using for example WHO's classification of diseases as a starting point, an example of the problems is given in the article, with reference to both methodological and philosophical points of view. It is suggested that pragmatic taxonomies with several dimensions, which would be useful for more than just a handful of clinicians, should be created. Subsequently, this type of classification can be revised in accordance with theoretical ideal requirements and considerations.