In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 32, No. 3_suppl ( 2014-01-20), p. 587-587
Abstract:
587 Background: Exploratory biomarker studies in the randomized phase III PRIME study suggested that patients with mCRC tumors harboring a mutation (MT) in KRAS or NRAS (beyond KRAS exon 2) do not respond to panitumumab-FOLFOX4 (2013 ASCO, JCO 31, #3511). We reported the efficacy and safety of S-1+. Cetuximab (Cmab) in wild-type (WT)-KRAS (exon 2) mCRC patients (pts) as third-line therapy (KSCC0901) (2012 ASCO, JCO 30, s3558). The full spectrum of characterized RAS (KRAS and NRAS), PI3CA, and BRAFMTs may affect efficacy in S-1+Cmab therapy in Japanese patients. Methods: An analysis was conducted to assess the treatment effect of S-1+Cmab, according to RAS (KRAS and NRAS), PI3CA, and BRAF MTs. The treatment protocol of KSCC0901 was as follows: weekly intravenous Cmab administration of 400 mg/m 2 (day 1), 250 mg/m 2 /week (following day 1) and oral administration of 80 mg/m 2 /day S-1 on days 1–28 of each 42-day cycle. MTs in KRAS codons 12 and 13 (exon 2) were detected using direct sequencing according to the manufacturer’s instructions. MTs in KRAS codons 61 and 146, NRAS codons 12, 13 and 61, BRAF codon 600 and PIK3CA codons 542, 545, 546, and 1047 were detected using the multiplex PCR-Luminex method-based MEBGEN MT Kit (Medical and Biological Laboratories, Nagoya, Japan). Results: 35 pts were eligible for the analysis. Number of MT cases of KRAS, NRAS, BRAF, and PIK3CA were 4, 2, 2, and 5, respectively. One case had MTs of NRAS and PIK3CA. In 37 cases with WT KRASexon2 pts, median progression-free survival (mPFS) was 5.6 [95% CI: 4.4 – 5.7] months; median overall survival (mOS), 13.5 [8.5-16.5] months; and best overall response (ORR), 37.8%. In the all-WT subgroup 23 cases, mPFS was 5.6 [5.1-7.1] months; mOS, 13.5 [9.3-21.2] months; and best ORR, 47.8%. In 12 patients with any MT, mPFS was 4.0 [2.7-7.5] months; mOS, 5.5[2.9- ] months; and best ORR, 16.7%. Conclusions: These results suggest that also in Japanese patients receiving a Cmab containing regimen, RAS, BRAF and PIK3CA MT status beyond KRAS exon2 might predict non-responders to treatment. Clinical trial information: UMIN000002475.
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/jco.2014.32.3_suppl.587
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2014
detail.hit.zdb_id:
2005181-5
