BRAFV600E mutations are found in 10% of colorectal cancers (CRCs). The low frequency of this mutation therefore makes it a challenging target for drug development, unless subsets of patients with higher rates of BRAF V600E can be defined. Knowledge of the concordance between primary-metastasis pairs and the impact of BRAF V600E on outcome would also assist in optimal drug development. We selected primary CRCs from 525 patients (stages I-IV) evenly matched for age (<70 and !70), gender and tumor location (right, left and rectum), and 81 primary-metastasis pairs. BRAF V600E , KRAS mutation and microsatellite instability (MSI) were determined and correlated with clinical features and patient outcomes. In multivariate analyses, increasing patient age (p 5 0.04), female gender (p 5 0.0005) and right-sided tumor location (p < 0.0001) were independently associated with BRAF V600E . The prevalence of BRAF V600E was considerably higher in older (age > 70) females with KRAS wild-type right-sided colon cancers (50%) compared to the unselected cohort (10%). BRAF V600E was associated with inferior overall survival in metastatic CRC (HR 5 2.02; 95% CI 1.26-3.26), particularly evident in patients treated with chemotherapy, and is independent of MSI status. BRAF status was concordant in all primary tumors and matched metastases (79 wild-type pairs and two mutant pairs). Clinicopathological and molecular features can identify CRC patients with a higher prevalence of BRAF V600E . Patients with BRAF V600E wild-type primary tumor do not appear to acquire the mutation in their metastases, and BRAF V600E is associated with poorer outcomes in metastatic patients. Our findings are timely and will help inform the rational development of BRAF V600E inhibitors in CRC.

The cobas test (1) had a lower assay failure rate than that of Sanger, (2) was more sensitive in detecting V600E mutations, (3) detected most V600K mutations, and (4) was highly reproducible.

Melanomas frequently harbor BRAFV600 mutations. Vemurafenib (RG7204/PLX4032), a small-molecule inhibitor of mutant BRAF, has shown striking clinical efficacy in BRAFV600 mutant melanoma, creating the need for a well-validated companion diagnostic to select patients for treatment. We describe analytic performance characteristics of the cobas 4800 BRAF V600 Mutation Test, the test used to select patients for the pivotal vemurafenib trials. This real-time polymerase chain reaction assay was designed to detect the V600E (1799T>A) mutation DNA from formalin-fixed paraffin-embedded tissue samples. Sensitivity was assessed using blends of cell lines or tumor DNA, and tumor specimens with low levels of mutant alleles, as determined by 454 sequencing (a quantitative next-generation pyrosequencing method). A >96% hit rate was obtained across all specimen types with 5% mutant alleles at a DNA input of 125 ng, an amount readily obtained from one 5-μm section. The cobas test showed a higher sensitivity and specificity than direct bidirectional sequencing in a panel of 219 melanoma specimens. Cross reactivity with V600K and V600D was observed. Repeated testing of 5 specimens by 2 operators, using different instruments and reagent lots, yielded correct calls in 158/160 tests (98.8%). A set of 26 highly pigmented samples were identified that gave invalid test results. A simple 1:2 dilution resulted in a valid test result of 76% in such cases. The cobas test is a reproducible assay that detects some non-V600E mutations and is more accurate than direct sequencing in detecting BRAFV600E.

Preclinical data suggest that inhibition of the metabotropic glutamate receptor 5 (mGluR5) receptor might hold therapeutic benefits in Fragile X syndrome (FXS). Treatment of Fmr1 knockout mice with mGluR5-negative allosteric modulators (NAMs) has been reported to correct a broad range of phenotypes related to FXS. The early short-term clinical trials with mGluR5 NAMs, including basimglurant, assessing the effects in individuals with FXS, were supportive of further exploration in larger, well-controlled trials. We evaluated basimglurant, a potent and selective mGluR5 NAM, in a 12-week, double-blind, parallel-group study of 183 adults and adolescents (aged 14–50, mean 23.4 years) with FXS. Individuals with an FMR1 full mutation were randomized to placebo or one of two doses of basimglurant. The primary efficacy endpoint was the change from baseline in behavioral symptoms using the Anxiety Depression and Mood Scale (ADAMS) total score. All treatment arms showed marked behavioral improvements from baseline to week 12 with less improvement in the basimglurant 1.5 mg arm than placebo; however, basimglurant 0.5 mg was inferior to placebo in the ADAMs total score. Treatment with basimglurant was overall well-tolerated. A higher incidence of adverse events classified as psychiatric disorders were reported in patients treated with basimglurant, including three patients with hallucinations or psychosis. In this phase 2 clinical trial, basimglurant did not demonstrate improvement over placebo. Evaluation of the overall risk-benefit in younger patient populations is an important consideration for the design of potential further investigations of efficacy with this class of medications.