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120 Background: Triplet regimen, FOLFOXIRI, plus bevacizumab is considered as one of standard first-line treatments in metastatic colorectal cancer (mCRC). On the contrary, FOLFOXIRI plus anti-EGFR antibody has been shown to be a promising regimen with greater depth of response (DpR) in patients with RAS wild-type mCRC from the VOLFI and MACBETH trials (J Clin Oncol 2019, JAMA Oncol 2018). We therefore performed a randomized phase II study, DEEPER trial (JACCRO CC-13) [NCT02515734], to investigate the efficacy and safety of cetuximab (cet) vs. bevacizumab (bev) in combination with modified (m)-FOLFOXIRI in previously untreated mCRC patients with RAS wild-type tumors. We have reported a significantly better DpR of m-FOLFOXIRI plus cet compared to bev as the primary endpoint (Tsuji A, et al. ASCO 2021). Methods: This trial was a randomized phase II trial to evaluate modified (m)-FOLFOXIRI (irinotecan 150 mg/m2, oxaliplatin 85 mg/m2, 5-FU 2400 mg/m2) plus cet vs. bev as initial treatment in terms of DpR during the entire course as the primary endpoint in 360 patients with RAS wild-type mCRC. The aim of the trial was to show that median DpR of cet arm was more than 12.5% higher than bev arm, with a power of 85% at a significance level of 0.05, in per protocol set (PPS) consisted of patients evaluable for the DpR. Secondary endpoints included progression-free survival, overall survival, overall response rate, early tumor shrinkage rate, secondary resection rate, and toxicity. A total of 359 patients were enrolled between July 2015 and June 2019. For the PPS (median age 65y, 64% male, PS0/1: 91%/9%, left/right primary: 84%/16%), 159 and 162 patients were randomly assigned to the cet and bev arms, respectively. Clinical outcomes will be analyzed according to primary tumor sidedness which is included in the stratification factor. Additionally, we will collect data of BRAF status, and analyze the clinical outcomes in mCRC patients with RAS/ BRAF wild-type tumors and/or left-sided tumors. Pre-planned survival analysis will be performed to compare the two treatment arms at the time of 3 years after last patients’ enrollment using a log-rank test. All statistical tests are two-sided, and P values ≤ 0.05 are deemed significant. Statistical analyses will be performed using SAS version 9.4. Clinical trial information: NCT02515734 .

112 Background: Ramucirumab (RAM) plus FOLFIRI has been considered as the standard care of second-line treatment in metastatic colorectal cancer (mCRC). However, there have been few data which prospectively evaluated the efficacy and safety of RAM or other anti-VEGF drugs plus FOLFIRI after anti-EGFR antibody therapy in RAS wild-type mCRC. We therefore investigated the efficacy and safety of RAM plus FOLFIRI as second-line treatment in patients with RAS wild-type mCRC previously treated with oxaliplatin-containing chemotherapy with anti-EGFR antibody. Methods: The JACCRO CC-16 was a multicenter, phase 2 trial to evaluate the efficacy and safety of RAM (8 mg/kg) plus FOLFIRI (irinotecan 150 mg/m2, bolus 5-FU 400 mg/m2, infusional 5-FU 2400 mg/m2) in mCRC patients with RAS wild-type tumors and ECOG PS 0 or 1, after first-line doublet or triplet plus anti-EGFR antibody therapy. The primary endpoint was 6-month progression-free survival (PFS) rate. The secondary endpoints included PFS, overall survival, objective response rate (ORR), early tumor shrinkage (ETS), and safety. We hypothesized a threshold 6-month PFS rate of 30% and an expected 6-month PFS rate of 45% for the protocol treatment. A sample size of 74 patients was required (one-sided α, 0.05; β, 0.2). Results: A total of 92 patients were enrolled between October 2018 and December 2020. Ninety-one patients, excluding one ineligible patient, were analyzed as the full analysis set: median age 66.0-y (range, 29–84), 46% female, 81% ECOG PS 0, 40% with primary tumor, 95% left-sided (rectum, sigmoid or descending colon) primary tumors, 70%/42% with liver/lung metastases. In prior first-line treatment, 19 (21%) patients were treated with triplet plus anti-EGFR antibody. The median number of treatment cycles was 10 (range, 1–56). Primary endpoint was met; at data cut-off, with 76 events, 6-month PFS rate was 58.2% (95% CI; 47.4-67.6). The median PFS was 7.0 months. The ORR, disease control rate, and ETS were 10.7%, 86.9%, and 16.9%, respectively. In the safety population of 92 patients, any grade adverse events (AEs) were neutropenia (75%), hypertension (59%), proteinuria (34%), and diarrhea (33%). Grade 3-4 AEs were neutropenia (48%), hypertension (27%), proteinuria (4%), diarrhea (3%), and febrile neutropenia (3%). No treatment-related death was observed. Conclusions: This is the first prospective study to demonstrate that RAM plus FOLFIRI as second-line treatment has favorable PFS rate and tolerability after anti-EGFR antibody containing chemotherapy in RAS wild-type mCRC patients. Clinical trial information: jRCTs061180002.

86 Background: Triplet regimens, FOLFOXIRI, combined with bevacizumab (bev) or panitumumab have been shown to be superior in terms of early tumor shrinkage (ETS) and depth of response (DpR) compared to doublet regimen plus bev or triplet regimen in patients with RAS wild-type metastatic colorectal cancer (mCRC), in the TRIBE trial ( N Engl J Med 2014) or VOLFI trial ( J Clin Oncol 2019), respectively. There have been few studies which directly compared cetuximab (cet) with bev when combined with triplet regimen. Therefore, we investigated the efficacy and safety of bev vs. cet in combination with FOLFOXIRI in previously untreated mCRC patients with RAS wild-type tumors. Methods: This trial was a randomized phase II trial to evaluate modified (m)-FOLFOXIRI (irinotecan 150 mg/m2, oxaliplatin 85 mg/m2, 5-FU 2400 mg/m2) plus cet vs. bev as first-line treatment in terms of the DpR during the entire course as the primary endpoint in 360 patients with RAS wild-type mCRC (ClinicalTrials.gov Identifier: NCT02515734). The experimental arm with cet was considered to be active if the difference of median DpR was over 12.5% compared with the bev arm, under the conditions of significance level of 0.05 and power of 0.85. Secondary endpoints included the ETS at week 8, progression-free survival, overall survival, secondary resection rate, and toxicity. Results: A total of 359 patients were enrolled between July 2015 and June 2019. For the safety analysis set (median age 65y, 64% male, PS0/1:91%/9%, left/right primary:83%/17%), 173 and 175 patients were randomly assigned to the cet and bev arms, respectively, some patients were excluded for the safety analysis due to the violation of inclusion criteria (6 for cet arm and 5 for bev). On the cutoff date of September 2020, median number of cycles administered was 10 (range, 1-51) for the cet arm and 12 (range, 1-51) for the bev arm. The incidence of severe adverse events (AEs) was 25.4% (44/173) for the cet arm and 25.7% (45/175) for the bev arm, respectively. The following AEs of grade 3-4 were observed more frequently in the cet arm compared to the bev arm: oral mucositis (9.2% vs. 2.3%), diarrhea (12.1% vs. 8.0%), dermatitis acneiform (12.1% vs. 0%), and hypomagnesemia (4.0% vs. 0%). The treatment-related death occurred in 2 patients of the cet arm, while no patients in the bev arm. The rate of treatment discontinuation due to AEs of any cause was comparable between the cet and bev arms (7% vs. 9%). Conclusions: This safety analysis indicated that both regimens of m-FOLFOXIRI plus cet or bev were tolerable in RAS wt mCRC patients although some frequent severe AEs were observed. Clinical trial information: UMIN000018217.

e14147 Background: In Japan, much labor has been devoted to handle occupational exposure to hazardous drugs (HDs) after the publication of a guideline for preventing HD exposure on cancer treatments in 2015. However, the safe HD handling systems have not yet constructed in Japanese hospitals. To find out the current HD exposure and construct the safe HD handling system, a multi-institutional surveillance of HD exposure in the National Hospital Organization (NHO) cancer hospitals was commenced from Feb 2016 to Mar 2018. Methods: Thirty-two NHO institutes joined in this survey. HD surveys were performed 3 times in each institute, evaluating cyclophosphamide and fluorouracil exposures using wipe and sampling sheet methods at 18 places in outpatient chemotherapy and pharmacology units. To share information and discuss about HD exposure handling procedures, the study group meeting was held several times. Furthermore, HD handling system in each hospital was evaluated using handling system scoring established by Yoshida in Osaka Institute of Public Health. As an additional study, factors affecting commitment wills of staffs were also evaluated during the safe HD handling system construction using a multiple regression model. Results: As HD control systems constructed, HD exposure in each hospital was improved gradually with construction of the handling system. Staffs’ commitment to their institutes was shown as the result of safety awareness improvement induced by the HD safe handling system construction (standardization coefficient β: 0.346). Conclusions: HD exposures were improved in NHO cancer hospitals through the HD exposure evaluation with constructions of the safe HD handling system.

121 Background: We have conducted the multicenter, phase Ib/II study to assess the activity and safety of biweekly Trifluridine/tipiracil (FTD/TPI) plus bevacizumab (BEV) combination for pts with metastatic colorectal cancer (mCRC) who were refractory or intolerant to standard therapies, and the primary endpoint of investigator assessed progression-free survival rate at 16 weeks (16w-PFS) was met [Kotaka M, ASCO-GI 2018]. We show longer follow-up data from this prospective study. Methods: Patients with unresectable mCRC; refractory or intolerant to standard chemotherapies were enrolled. Phase Ib part is designed to determine the recommended phase II dose (RP2D), and the treatment was determined as biweekly FTD/TPI (70mg/m2/day on day 1-5, every 2 weeks) with BEV (5mg/kg, every 2 weeks). The primary endpoint in phase II part was a 16w-PFS with a hypothesis of 15% considered unacceptable and 38.7% deemed promising. Given a one-sided α of 0.025 and statistical power of 90%, a minimum of 40 pts were required for phase II part. This trial registered in University Hospital Medical Information Network, number UMIN000029198. Results: From October 2017 to January 2018, totally 46 pts were enrolled. Nine patients (20.5 %) received regorafenib before enrollment. Of the 44 eligible pts, 16w-PFS rate was 40.9 %. With a median follow up of 15.36 months (range, 2.79-16.93), median PFS was 4.29 months (95% CI: 2.54 to 5.83), median TTF was 4.16 months (95% CI: 2.39 to 5.82), and median OS was 10.86 months (95% CI:8.32 to 13.68), respectively. Disease control rate was 59.1 % (95%CI: 43.3 to 73.7 %). Patients received the study treatment for a median of 6.5 cycles (range, 1 to 24). The median relative dose intensity of FTD/TPI and BEV was 80.9% (range: 44.0 to 100%), 81.5% (range: 50.0 to 100%), respectively. Common grade 3 or higher adverse events were hypertension (40.9%), neutropenia (11.4 %) and leucopenia (11.4 %). Conclusions: An update analysis confirmed that biweekly FTD/TPI plus BEV showed promising anti-tumor effect with acceptable less toxicities, and might be one of the treatment options for patients with heavily treated mCRC. Clinical trial information: UMIN000029198.

399 Background: Prognosis for locally advanced gastric cancer (LAGC), such as clinical T4 disease, bulky nodal metastases, type 4 and large type 3 gastric cancer, was not satisfactory even by D2 gastrectomy followed by adjuvant chemotherapy. Neoadjuvant chemotherapy is another promising approach, therefore, we have conducted a phase II study to evaluate the efficacy and safety of the neoadjuvant chemotherapy of S-1 and oxaliplatin (G-SOX) followed by gastrectomy with D2/3 lymph node dissection for LAGC, and the primary endpoint of curative resection rate was met [Miki A, ESMO 2019]. We show longer follow-up data from this study. Methods: Patients with adenocarcinoma of the stomach; clinical T4; clinically resectable gastric cancer of type 4 or large type 3; bulky nodal involvement around major branched arteries to the stomach were enrolled. Patients receive two cycles of neoadjuvant chemotherapy with S-1 (80 mg/m2, p.o., days 1-14 followed by 1 week rest) and oxaliplatin (130 mg/m2 at day 1), followed by D2 or higher surgery with no residual disease. Patients with pathological R0/1 resection received S-1 (80 mg/m2, p.o., days 1-28 followed by 2 week rest) for 1 year as adjuvant chemotherapy. Primary endpoint was curative resection rate. Results: Between August 2015 and March 2017, forty-one patients were in enrolled. Of the patients, 39 patients (95%) completed the two courses of neoadjuvant chemotherapy of G-SOX, 37 (90%) received gastrectomy, and 36 (87.8%) received curative resection (R0/1). Grade 3 or higher toxicities during neoadjuvant chemotherapy of G-SOX were neutropenia (7%), fatigue (7%), diarrhea (5%) and thrombocytopenia (2%). No treatment related deaths were observed. Surgical complications including postoperative complications were observed in 13 patients (35%). Pathological response rate after neoadjuvant G-SOX was 40%. With a median follow-up period of 33.8 months, 3year-relapse free survival and 3year-ovearll survival was 54.3% and 73.1%, respectively. Conclusions: An update analysis confirmed that neoadjuvant chemotherapy of G-SOX is a feasible and might be one of the promising strategies for patients with LAGC. Clinical trial information: UMIN000018661.

1083 Background: Anthracycline regimens and taxane have been first line chemotherapeutic options for HER2 negative metastatic breast cancer. In a previous phase III trial (SELECT BC), non-inferiority of S-1 was demonstrated in terms of overall survival (OS). The SELECT BC-CONFIRM study was designed to confirm the results of the SELECT BC study and to combine the two randomized studies. Methods: Patients (n = 618) in the first trial were randomly assigned (1:1) to the S-1 group or the taxane group. Patients (n = 230) in the second trial (SELECT BC-CONFIRM) were randomly assigned to the anthracycline group or the S-1 group. Treatment continued until tumor progression, unacceptable toxic effects, or completion of six courses in the standard regimen group and four courses in the S-1 group. The primary endpoint was OS and secondary endpoints were progression-free survival (PFS), time to treatment failure, adverse events, HRQOL and cost-effectiveness. A pooled analysis of the two studies was predefined to confirm the results of the SELECT BC study. Results: 1. The HR for the anthracycline group was 1.09 [95%CI 0.80-1.48] in SELECT BC-CONFIRM, and the estimated predictive posterior probability that the HR does not exceed the threshold 1.333 was 90.27%. 2. Median OS was 32.7 months (S-1 group) and 36.3 months (standard treatment group). S-1 was not inferior to standard treatment in terms of OS (p non-inferiority = 0.0062). Median PFS was 11.2 months (S-1 group) and 11.2 months (standard treatment group). 3. Treatment was discontinued due to adverse events (i.e., neutropenia, febrile neutropenia, fatigue and edema) in 5.7% in the S-1 group and 6.6% in the standard treatment group 4. The EORTC QLQ-C30 questionnaire (global health status) revealed that there was no difference between the S-1 and anthracycline groups (p = 0.257), but there was a significant difference between the S-1 and taxane groups (p = 0.0039). Conclusions: S-1 is not inferior to taxane or anthracycline with respect to OS as a first-line treatment for MBC. S-1 should be considered a new option as a first-line chemotherapy for HER2-negative metastatic breast cancer patients. Clinical trial information: UMIN000005449.

TPS3621 Background: A randomized phase II trial, DEEPER (JACCRO CC-13) [NCT02515734], is on-going to evaluate FOLFOXIRI plus cetuximab (cet) vs. FOLFOXIRI plus bevacizumab (bev) in terms of depth of response as primary endpoint in 360 mCRC patients (pts) with RAS wild-type tumors, PS0-1, and no previous chemotherapy. This is a head-to-head comparative trial of 2 key monoclonal antibodies in mCRC treatment; therefore, it would be of interest to perform the biomarker study for developing novel predictors of cet or bev. The clinical utility of circulating tumor DNA (ctDNA) analysis has been largely validated for monitoring during treatment and companion diagnostics after chemotherapy. However, there are few published results regarding ctRNA in cancer treatment. Use of ctRNA from liquid biopsies would enhance tumor profiling through the trending of actionable biomarkers not found in ctDNA, and allow for patient monitoring by measuring dynamic changes in levels of gene expressions. Methods: This study will enroll pts with willing to undergo biopsies of both tissue and blood among participants of the DEEPER trial. The estimated number is 250. The main purpose is to find novel predictors for efficacy of cet or bev in mCRC using liquid biopsies, which are performed to obtain ctDNA and ctRNA at 6 time points: pre-treatment, 8 weeks after treatment start, beginning of maintenance phase in FOLFOXIRI-regimen, progression, before and 8 weeks after 2nd-line treatment. The tissue samples collected before chemotherapy will be used for analyzing intra-tumoral genetic alterations. Associations between analytes in blood/tissue and the clinical outcomes of each treatment (with cet or bev) will be assessed using Fisher’s exact test, Kaplan-Meier curves, and log-rank tests in univariate analyses. We will evaluate on whether transcriptomic analysis in ctRNA could predict treatment efficacy more accurately compared to genomic analysis in ctDNA, and verify the clinical utility of ctRNA testing in mCRC treatment. Accrual will continue until the DEEPER trial is completed. Clinical trial information: UMIN000018412.

543 Background: We have reported that carcinoembryonic antigen (CEA) response correlated with clinical outcomes of 1st-line cet-based therapy (Target Oncol 2017). Early tumor shrinkage (ETS) is considered to be an on-treatment biomarker for outcomes of chemotherapy; however, clinical biomarkers to predict outcomes earlier are warranted. Methods: This study included 69 pts who were assessable for CEA at baseline and 4 wks, and with observed survival time from 2 phase II trials of 1st-line therapy for KRAS exon2 wild-type mCRC; JACCRO CC-05 of cet plus FOLFOX (UMIN000004197) and CC-06 of cet plus SOX (UMIN000007022). We investigated the influence of baseline age, gender, PS, primary tumor sidedness (PTS), number of tumor sites, as well as the CEA decrease at 4 wks to the patient’s OS and PFS. Results: PTS and the CEA decrease at 4 wks were found to be important predictors to OS and PFS. Baseline CEA and CEA decrease at 4 wks were median of 31.0 (range, 1.0-20920.0) and median of 35% (range, -259%-97%), respectively. The STEP-analysis indicated that CEA response was most significantly associated with OS when a cut-off value of 50% for CEA-responder (HR 0.49, log-rank test p = 0.03). Median OS in responders (n = 25) and non-responders (n = 44) were 36.2 m and 21.5 m, respectively. When the same cut-off value was used, median PFS in responders and non-responders were 11.6 m and 6.5 m, respectively (HR 0.64, log-rank test p = 0.08). In addition, a multivariate Cox Proportional-Hazards Model with both PTS and CEA response as risk factors showed that PTS correlated with both OS and PFS. In pts with left-sided tumors, non-responders (n = 33) had shorter OS and PFS compared to responders (n = 23). In the above 2-covariate Cox proportional hazard model, adjusted HR for CEA 50% decrease is 0.55, p = 0.1; adjusted HR for PTS is 2.66, p = 0.008. Conclusions: Our analysis suggests 50% CEA decrease at 4 wks as an early on-treatment biomarker for 1st-line cet-based therapy in mCRC. It may potentially predict outcomes earlier compared to ETS. Also, CEA response at 4 wks may differentiate pts who receive more benefit from cet treatment in left-sided tumors. Clinical trial information: UMIN000004197 and UMIN000007022.

647 Background: Trifluridine/tipiracil (FTD/TPI) plus bevacizumab (Bmab) combination therapy has shown a promising activity with manageable safety profile in patients (pts) with heavily pretreated metastatic colorectal cancer (mCRC). The aim of this multicenter, phase Ib/II study was to assess the activity and safety of biweekly FTD/TPI with Bmab combination for pts with mCRC who were refractory or intolerant to standard therapies. Methods: Inclusion criteria were ≥ 20 years; histologically confirmed unresectable mCRC; refractory or intolerant to fluoropyrimidine, irinotecan, oxaliplatin, anti-VEGF therapy, and anti-EGFR therapy (for tumors with wild-type RAS); ECOG PS 0 or 1; evaluable lesion according to the RECIST version 1.1. Phase Ib part is designed to determine the recommended phase II dose (RP2D), and pts received the RP2D in phase Ib part were included in efficacy and safety populations. The primary endpoint in phase II part was an investigator assessed progression-free survival rate at 16 weeks (16w-PFS) with a hypothesis of 15% considered unacceptable and 38.7% deemed promising. Given a one-sided α of 0.025 and statistical power of 90%, a minimum of 40 pts were required for phase II part. Results: From October 2017 to January 2018, totally 46 pts were enrolled (6 pts in phase Ib and 40 pts in phase II). The RP2D was determined to be 5 mg/kg for Bmab and 30 mg/m2 for FTD/TPI in phase Ib. Of the 44 eligible pts (median age, 69; male, 55%; PS 0, 57%; right-sided primary, 29.5%), 16w-PFS rate was 40.9 % (95% CI: 26.3 to 56.8 %) and the null hypothesis of 16w-PFS rate ≤ 15% was rejected (p < 0.0001). Response rate and disease control rate were 0 % (95 %CI: 0 to 6.6 %) and 59.1 % (95%CI: 43.3 to 73.7 %), respectively. With a median follow up of 5.86 months (range, 1.53-9.79), median PFS was 4.25 months (95% CI: 2.54 to 5.57). Grade 3 or higher adverse events were hypertension (40.9%), neutropenia (11.4 %), leucopenia (11.4 %), anemia (9.1 %), anorexia (9.1 %), nausea (6.8 %), hyperbilirubinemia (6.8 %) and proteinuria (6.8 %). Conclusions: Bi-weekly FTD/TPI plus Bmab showed promising anti-tumor effect with acceptable toxicities. Clinical trial information: UMIN000029198.

635 Background: We have reported that modified (m)-FOLFOXIRI plus bev was feasible and had a good objective response rate (ORR) for Japanese patients (pts) in a phase II trial of the JACCRO CC-11 (ESMO 2017 #543P). In addition, a pre-planned research was performed to investigate if the change of gene mutations in ctDNA during therapy can serve as a predictor for clinical outcomes in RAS mutant mCRC. Methods: The efficacy of m-FOLFOXIRI (irinotecan 150 mg/m², oxaliplatin 85 mg/m², levofolinate 200 mg/m², and fluorouracil 2400 mg/m² repeated biweekly) plus bev was evaluated prospectively in 62 pts (median age 63, 55% male, 92% PS0, and 27% right-sided tumors) with mCRC harboring RAS mutation (mt). The primary endpoint was ORR. Progression-free survival (PFS), overall survival, early tumor shrinkage (ETS), depth of response (DpR), and safety were secondary endpoints. Plasma samples for extraction of ctDNA were collected at 3 points (pre-, 8w, and progression) and analyzed for specific KRAS, NRAS, BRAF, and PIK3CA variants with real-time PCR assays. Results: Updated median follow-up time was 10.2 months. ORR and disease control rate were 75.8% and 96.8%, respectively. ETS was 73.8%, and median DpR was 49.6%. Median PFS was 11.5 months (95%CI 9.5-14.0). KRAS/ NRAS mt from pre-treatment plasma was confirmed in 79% of pts. In 41 pts with RAS mt at pre-treatment, mt status at 8 weeks predicted clinical outcomes (Table). Moreover, combined assessment of mt in ctDNA and ETS served as a refined predictor for efficacy. Pts with PIK3CA mt at pre-treatment had a poor outcome (ORR, 43%; median PFS, 8.8 months). Conclusions: FOLFOXIRI plus bev regimen is active for RAS mutant mCRC. RAS mt in ctDNA and ETS evaluation might potentially be a useful on-treatment biomarker in mCRC pts with RAS mt. Clinical trial information: UMIN000015152. [Table: see text]

866 Background: Hepatic resection is one of the treatment strategies for resectable colorectal cancer liver metastases (CLM). The role of neoadjuvant and adjuvant chemotherapy in the management of initially resectable CLM is still unclear. Adjuvant chemotherapy consisting of capecitabine plus oxaliplatin (CapeOx) appears to be equivalent to FOLFOX in patients with stage III colon cancer. Furthermore, the IDEA collaboration reported that adjuvant chemotherapy with the three months of CapeOx after curative resection for stage III colon cancer has equivalent efficacy to adjuvant chemotherapy for 6 months. We conducted a multi-institutional, single-arm, phase II trial to confirm the feasibility of the three months of adjuvant CapeOx for post curative resection of CLM. Methods: Patients received one course of capecitabine followed by four courses of CapeOx for a total five courses (15 weeks) as adjuvant chemotherapy after curative resection of CLM. Oral capecitabine was given with 1,000 mg/m2 twice daily for 2 weeks in a 3-week cycle, and CapeOx consisted of oral capecitabine plus oxaliplatin 130 mg/m2 on day 1 in a 3-week cycle. The primary endpoint was completion rate of adjuvant chemotherapy. We set a threshold completion rate of protocol treatment of 45% and an expected completion rate of 70%. Given a one-sided α of 0.1 and statistical power of 80%, a minimum of 25 patients was required. Results: From May 2013 to November 2015, Twenty-eight patients were enrolled from six institutions: median age 69.5y, 54% male, 78.5% left-sided primary. Of the patients, 15 were synchronous metastases and 13 were metachronous. The locations of the metastases were unilobar in 20 patients and bilobar in 8. The mean number of lesions resected was two (range, 1 to 4). Among the 28 patients, 20 (71.4%: 95% CI, 53.6 to 89.3%) completed the protocol treatment. The most common grade 3/4 toxicities were neutropenia (29%). No treatment related death was observed. With a median follow-up period of 36 months (range 15-53months), 3 year-relapse free survival was 75.3%. Conclusions: The three months of adjuvant CapeOx is tolerable for post curative resection of CLM. Clinical trial information: 000011164.

e23274Background: S-1 is oral fluoropyrimidine which is a biochemically modulated drug to increase 5-FU concentration and to avoid gastrointestinal toxicities. SELECT-BC, a randomized phase III tri...

TPS180 Background: Prognosis for locally advanced gastric cancer, such as clinical T4 disease, bulky nodal involvement, type 4 and large type 3 gastric cancer, was not satisfactory even by D2 gastrectomy followed by adjuvant chemotherapy. Neoadjuvant chemotherapy is another promising approach. In our phase I study, neoadjuvant chemotherapy of S-1 and oxaliplatin (SOX) had manageable toxicities and good pathological complete response rate (33%) in patients with locally advanced gastric cancer. Based on the results of this phase I study, we initiate a multi-institutional, single-arm, open label, phase II study (Neo G-SOX PII study). The aim of this study is to evaluate the efficacy and safety of the neoadjuvant chemotherapy of S-1 and oxaliplatin (SOX) followed by gastrectomy with D2/3 lymph node dissection; clinical T4; clinically resectable gastric cancer of type 4 or large type 3 (over 8 cm); bulky nodal involvement around major branched arteries to the stomach Methods: Eligibility criteria include histologically proven adenocarcinoma of the stomach; clinical T4; clinically resectable gastric cancer of type 4 or large type 3 (over 8 cm); bulky nodal involvement around major branched arteries to the stomach; resectable peritoneal dissemination (pathological CY1 or P1, except for clinical CY1 or P1). Patients receive two cycles of neoadjuvant chemotherapy with S-1 (80 mg/m2, p.o., days 1-14 followed by 1 week rest) and oxaliplatin (130 mg/m2 at day 1), followed by D2 or higher surgery with no residual disease. Patients with pathological R0/1 resection received S-1 (80 mg/m2, p.o., days 1-28 followed by 2 week rest) for 1 year as adjuvant chemotherapy. Primary endpoint is curative resection rate. Key secondary endpoints include pathological response, R0/1 resection rate, dose-intensity, overall survival, relapse free survival and safety. We set the threshold curative resection rate at 65% and the expected curative resection rate at 80%. Given a one-sided α of 0.1 and statistical power of 80%, 40 patients was required. Clinical trial information: UMIN000018661 Clinical trial information: UMIN000018661.

e17673 Background: Hair loss is a distressing side effect of chemotherapy. We conducted a national survey to evaluate the effects of chemotherapy on change in appearance and the status of support f...

1012 Background: Taxanes have been standard regimen as the first-line chemotherapy for metastatic breast cancer. However side effects such as neutropenia, peripheral neuropathy, edema or alopecia are important concerns. Phase II clinical trials of TS-1, an oral 5-fluorouracil derivatives (tegafur, 5-chloro-2,4-dihydropyrimidine, and potassium oxonate), have shown good clinical efficacy and tolerability. Therefore, we conducted a phase III open-label randomized controlled trial (SELECT BC) to verify the non-inferiority of TS-1 in overall survival (OS) to taxane as first-line chemotherapy for metastatic breast cancer. Methods: Six hundred eighteen patients receiving first-line chemotherapy for metastatic breast cancer were randomly assigned to either taxane group (n=309) or TS-1 group (n=309). In the taxane group, patients received docetaxel 60-75mg/m2 q3w, paclitaxel 80-100mg/m2 q1w or paclitaxel 175 mg/m2 q3w at the discretion of the treating physician. In the TS-1 group, patients received TS-1 40–60 mg t...

571 Background: Both SOX and cet are effective treatments each other in patients (pts) with mCRC. COIN trial indicated that the use of cet in combination with capacitabine and oxaliplatin should not be recommended. However, the safety and efficacy of cet plus SOX are not clear. To evaluate the safety and clinical efficacy of the combination, we conducted a multi-center phase I/II study. Methods: In this trial, we assigned pts with KRAS wild type (wt), EGFR-expressing tumor and no prior chemotherapy to receive cet (initial dose 400, and 250 mg/m2 weekly) followed by SOX (oxaliplatin on day 1 and S-1 40 mg/m2 twice daily on days 1-14). The treatment was repeated every 3 weeks. The phase I part was designed to determine the maximum tolerated dose (MTD) and recommended dose (RD) according to the dose adaptation schedule of oxaliplatin (100 mg/m2 for level 1 and 130 mg/m2 for level 2). In the following phase II part, the enrolled pts were treated with the RD. The primary endpoint was response rate (RR) evaluated by the external review board according to RECIST criteria v1.1. Secondary endpoints included PFS, OS, and safety. In addition, we prospectively evaluated early tumor shrinkage (ETS). Results: A total of 67 pts were enrolled from January 2012 to February 2013. In the phase I part, level 2 was determined to be the RD. The MTD was not determined because dose limiting toxicity was not confirmed in level 2. In the phase II part, 59 pts including 6 pts of phase I cohort were assessable for the efficacy. The median age was 64 years, 51% of pts were male, and ECOG PS 0 was observed in 85% of pts. The median course of treatment was 5 (range 1-14). The RR was 62.7% (95%CI, 50.4 to 75.1) and ETS was observed in 72% of pts. In safety analysis, grade 3 or worse adverse events were platelet count decreased (13.1%), neutropenia (8.2%), anorexia (11.7%), rash acneform (6.7%) and peripheral neuropathy (3.3%). Conclusions: We determined the RD of cet plus SOX treatment in pts with mCRC. This combination is tolerable at full doses of cet and SOX, with manageable toxicities, and demonstrates advantages in RR for pts with KRAS wt tumor. Updated safety and efficacy data will be presented. Clinical trial information: UMIN000007022.