Clinical Validation of a Multiplex Kit for RAS Mutations in Colorectal Cancer: Results of the RASKET (RAS KEy Testing) Prospective, Multicenter Study

AbstractBackgroundRAS (KRAS and NRAS) testing is required to predict anti-epidermal growth factor receptor (EGFR) treatment efficacy in metastatic colorectal cancer (CRC). Although direct sequencing (DS) with manual microdissection (MMD) is widely used, a diagnostic kit providing rapid detections of RAS mutations would be clinically beneficial. We evaluated the MEBGENTM RASKET KIT (RASKET KIT), a multiplex assay using PCR-reverse sequence specific oligonucleotide and xMAP® technology to concurrently detect exon 2, 3, and 4 RAS mutations in a short turnaround time (4.5h/96-specimens).MethodsFormalin-fixed paraffin-embedded (FFPE) tissues were obtained from 308 consenting patients with histologically-confirmed CRC at six hospitals in Japan. For the RASKET KIT, we used only 50–100ng DNA from each FFPE specimen not processed by MMD. The primary endpoint was the concordance rate between RAS mutations identified with the RASKET KIT and two reference assays (DS with MMD and TheraScreen® K-RAS Mutation Kit). As the secondary endpoints, we evaluated the concordance rate between DS and the RASKET KIT for RAS mutations in the wild-type KRAS exon 2 population and the genotyping performance of the RASKET KIT compared with DS.FindingsAmong 307 analyzable specimens, the reference assays detected 140 (45.6%, 140/307) RAS mutations: 111 KRAS exon 2 and 29 other (minor) RAS mutations. The RASKET KIT detected 143 (46.6%, 143/307) mutations: 114 KRAS exon 2 and 29 minor RAS mutations. The between-method concordance rate was 96.7% (297/307) (95% CI: 94.1–98.4%). Minor RAS mutations were detected in 15.7% (30/191) of the wild-type KRAS exon 2 population (n=191); the concordance rate was 98.4% (188/191) (95% CI: 95.5–99.7%). The concordance rate of RAS genotyping was 100% (139/139) (95% CI: 97–100%).InterpretationThe RASKET KIT provides rapid and precise detections of RAS mutations and consequently, quicker and more effective anti-EGFR therapy for CRC (Study ID: UMIN000011784).FundingMedical & Biological Laboratories Co., Ltd. (MBL). MBL had roles in study design, data collection, data analysis, and writing of the report for the study

The subgroups of the phase III RECOURSE trial of trifluridine/tipiracil (TAS-102) versus placebo with best supportive care in patients with metastatic colorectal cancer

Background: In the phase III RECOURSE trial, trifluridine/tipiracil (TAS-102) extended overall survival (OS) and progression-free survival (PFS) with an acceptable toxicity profile in patients with metastatic colorectal cancer refractory or intolerant to standard therapies. The present analysis investigated the efficacy and safety of trifluridine/tipiracil in RECOURSE subgroups. Methods: Primary and key secondary end-points were evaluated using a Cox proportional hazards model in prespecified subgroups, including geographical subregion (United States of America [USA], European Union [EU], Japan), age (<65 years, ≥65 years) and v-Ki-ras2 Kirsten rat sarcoma 2 viral oncogene homologue (KRAS) status (wild type, mutant). Safety and tolerability were reported with descriptive statistics. Results: Eight-hundred patients were enrolled: USA, n = 99; EU, n = 403; Japan, n = 266. Patients aged ≥65 years and those with mutant KRAS tumours comprised 44% and 51% of all patients in the subregions, respectively. Final OS analysis (including 89% of events, compared with 72% in the initial analysis) confirmed the survival benefit associated with trifluridine/tipiracil, with a hazard ratio (HR) of 0.69 (95% confidence interval [CI] 0.59–0.81; P = 0.0001). Median OS in the three regions was 6.5–7.8 months in the trifluridine/tipiracil arm and 4.3–6.7 months in the placebo arm (USA: HR 0.56; 95% CI 0.34–0.94; P = 0.0277; EU: HR 0.62; 95% CI 0.48–0.80; P = 0.0002; Japan: HR 0.75; 95% CI 0.57–1.00; P = 0.0470). Median PFS was 2.0–2.8 months for trifluridine/tipiracil and 1.7–1.8 months for placebo; HRs favoured trifluridine/tipiracil in all regions. Similar clinical benefits of trifluridine/tipiracil were observed in elderly patients and in those with mutant KRAS tumours. There were no marked differences among subregions in terms of safety and tolerability. Conclusions: Trifluridine/tipiracil was effective in all subgroups, regardless of age, geographical origin or KRAS status

Phase II trial of aflibercept with FOLFIRI as a second‐line treatment for Japanese patients with metastatic colorectal cancer

Aflibercept targets vascular endothelial growth factor. The present study involved assessing the efficacy, safety and pharmacokinetics of aflibercept plus 5‐fluorouracil/levofolinate/irinotecan (FOLFIRI) as a second‐line treatment for metastatic colorectal cancer (mCRC) in Japanese patients. Aflibercept (4 mg/kg) plus FOLFIRI was administered every 2 weeks in 62 patients with mCRC until disease progression, unacceptable toxicity or patient withdrawal. Tumors were imaged every 6 weeks. The primary endpoint was objective response rate (ORR); secondary endpoints were progression‐free survival, overall survival, safety, and pharmacokinetics of aflibercept, irinotecan and 5‐fluorouracil. A total of 60 patients were evaluated for ORR; 50 had received prior bevacizumab. The ORR was 8.3% (95% confidence interval [CI]: 1.3%‐15.3%), and the disease control rate (DCR) was 80.0% (69.9%‐90.1%). The median progression‐free survival was 5.42 months (4.14‐6.70 months) and the median overall survival was 15.59 months (11.20‐19.81 months). No treatment‐related deaths were observed, and no significant drug‐drug interactions were found. The most common treatment‐emergent adverse events were neutropenia and decreased appetite. Free aflibercept had a mean maximum concentration (coefficient of variation) of 73.2 μg/mL (15%), clearance of 0.805 L/d (22%) and volume of distribution of 6.2 L (18%); aflibercept bound with vascular endothelial growth factor had a clearance of 0.162 L/d (9%) (N = 62). Aflibercept did not significantly affect the pharmacokinetics of irinotecan or 5‐fluorouracil: The clearance was 11.1 L/h/m2 (28%) for irinotecan and, at steady state, 72.6 L/h/m2 (56%) for 5‐fluorouracil (N = 10). Adding aflibercept to FOLFIRI was shown to be beneficial and well‐tolerated in Japanese patients with mCRC. ClinicalTrials.gov Identifier: NCT01882868