Citations

752 Background: Elderly patients (≥65 yrs) with metastatic colorectal cancer (mCRC) are more likely to have comorbid conditions than younger patients ( < 65 yrs), limiting their therapeutic options. As previously reported (Mayer et al. J Clin Oncol 2017;35:abs 3559), FTD/TPI confirmed its clinical profile in mCRC in a real-world setting. Here, we report the safety and tolerability profile of FTD/TPI from the expanded-access program (EAP) in patients aged ≥65 yrs. Methods: Patients (≥18 yrs) with mCRC following ≥2 regimens of anticancer therapy and an Eastern Cooperative Oncology Group performance status of 0 or 1 were enrolled to this open-label EAP. Patients received FTD/TPI 35 mg/m2 twice daily for 5 days followed by 2 days’ rest for 2 weeks, with a 14-day rest period (28-day treatment cycle). Data were collected for therapy duration, treatment discontinuation, and adverse events (AEs). Results: Of 549 patients, 377 (68.7%) were aged < 65 and 172 (31.3%) were ≥65. The treatment duration of FTD/TPI was similar between < 65 and ≥65 yrs (Table). A lower proportion of those aged ≥65 had fatigue and nausea compared with < 65 (Table). However, the frequency of neutropenia and diarrhea was slightly increased in those ≥65 compared with < 65 (Table). One patient (0.6%) in the ≥65 group developed febrile neutropenia compared with 9 (2.4%) in the < 65 group, with no associated deaths in either group. Conclusions: This analysis from the EAP showed that the safety profile and treatment duration of FTD/TPI in patients aged ≥65 with mCRC were similar to those in patients aged < 65. FTD/TPI is well tolerated and can be considered in patients aged ≥65 with mCRC. Clinical trial information: NCT-02286492. [Table: see text]

728 Background: Adjuvant FOLFOX therapy for stage II patients remains controversial, and selection criteria are imprecise. We examined the trend of disease-free survival (DFS: time to recurrence or death, whichever occurs first); time to recurrence (TTR: time to recurrence, censored at death without recurrence); survival after recurrence (SAR); and overall survival (OS) of pts treated with FOLFOX over a ten-year period. Methods: Outcomes of pts with stage II colon cancer enrolled in 6 adjuvant trials receiving FOLFOX alone were analyzed. Pt enrollment period was dichotomized as old (1998 – 2003) vs. new era (2004 – 2009) based on the FDA approval date of bevacizumab. 3/5yr event-free rates were estimated using adjusted Kaplan-Meier methods. Outcomes were compared between the two eras by multivariate Cox model. To control for potential confounding effects, all analyses were adjusted for age, gender, performance score, T stage, number of lymph nodes (LNs) examined, tumor side, and histologic grade. Results: In total, 1,122 pts with stage II were identified; 71% and 29% were treated in the old and new era, respectively. Pts enrolled in the new era were significantly younger and more likely to have higher tumor-grade and right-sided tumors compared to old era. More pts in the new era (71%) had ≥12 LNs examined compared to the old era (53%). After adjusting for potential confounding effects, no difference in DFS, TTR, SAR or OS between old and new eras was found (Table). Although median SAR increased from 13.6 to 26 months over time, this was not statistically significant, likely due to lack of power. An increased TTR over time (HRadj. 0.41, padj.= 0.002) was observed in pts with ≥12 LNs examined (3-yr TTR: 92% in old era vs. 96% in new era), but not pts with <12 LNs examined (pinteraction = 0.04). Conclusions: In stage II colon cancer pts who received adjuvant FOLFOX, no significant increase of DFS or OS was observed over time. However TTR was longer only in pts with ≥12 LNs examined. [Table: see text]

726 Background: Primary tumor location is an important prognostic factor in mCRC. Efficacy differences with EGFR antibodies by tumor location show a predictive effect (Arnold et al. Ann Oncol 2017). Two first-line (1L) pivotal bev trials showed the prognostic value of sidedness (Loupakis et al. J Natl Cancer Inst 2015). In this exploratory study, further analysis of the predictive effect of bev is presented. Methods: Data from two randomized phase III studies (NO16966 [NCT00069095], AVF2107g [NCT00109070]) of bev+CT vs CT-alone as 1L treatment for mCRC were analyzed retrospectively. Patients (pts) with sidedness information available were included; pts from NO16966 (part 1) randomized to CT only were excluded. Sidedness was identified by case report forms. Results: Sidedness was determined in 1590 pts (27% Right and 73% Left) out of 2214 pts total (Table). In the pooled analysis, PFS improved with bev+CT compared to CT only in both right-sided (HR=0.75; 95% CI 0.61, 0.93) and left-sided (HR=0.76; 95% CI 0.67, 0.86) mCRC with similar magnitude of benefit in both sides. OS also improved with bev+CT in right-sided (HR=0.82; 95% CI 0.65, 1.03) and left-sided (HR=0.85; 95% CI 0.74, 0.98) pts. Conclusions: This exploratory subgroup analysis of two pivotal studies indicates that the effect of bev is independent of tumor location in mCRC patients. Survival outcomes. Clinical trial information: NCT00069095 and NCT00109070. [Table: see text]

724 Background: Adjuvant FOLFOX is the standard of care for pts with stage III colon cancer and a platform to test new agents. Improvements in supportive care and development of newer treatments for metastatic disease impact the overall outcome of pts treated with adjuvant therapy. We examined the trend of disease-free survival (DFS), survival after recurrence (SAR), and overall survival (OS) of pts treated with FOLFOX over a ten-year period. Methods: Outcomes of colon cancer pts enrolled in 6 adjuvant trials receiving FOLFOX alone were analyzed. Pt enrollment period was dichotomized as old (1998 – 2003) vs. new era (2004 – 2009) based on the FDA approval date of bevacizumab. 3/5yr event-free rates were estimated by adjusted Kaplan-Meier methods. Outcomes were compared between the two eras by Cox model. To control for potential confounding effects, all analyses were adjusted for age, gender, performance score, T/N stage, tumor sidedness and histologic grade. Results: In total, 7,230 pts (stage II [n = 1122]; stage III [n = 6,108]) were identified; 32% and 68% were treated in the old and new era, respectively. Stage III pts enrolled in the new era were significantly younger, more likely to have T4/N2 disease, higher tumor grade, and left-sided tumors. After adjusting for pt characteristics, no difference in DFS was seen over time. However prolonged SAR and OS were observed in pts treated in the new era (Table). 5yr OS increased from 76% to 80% over time. Median SAR improved from 14.8 to 26.4 months. Conclusions: Stage III colon cancer pts who received adjuvant FOLFOX experienced significant improvements in SAR and OS—but not DFS—over time. In view of the improvements in OS and nearly doubled SAR, the optimal duration of OS follow-up to evaluate the benefits of adjuvant therapy (currently 5 years) should be reassessed, and ACCENT investigators are planning to conduct these additional analyses using their large pooled-trial database. [Table: see text]

627 Background: The SLI of the BEACON CRC phase 3 study assessed the safety and efficacy of the combination of the BRAF inhibitor encorafenib (ENCO) + MEK inhibitor binimetinib (BINI) + anti-EGFR antibody cetuximab (CETUX) in pts with BRAFV600E-mutant mCRC after 1 or 2 prior regimens. CEA and CA19-9 are tumor markers that are widely used to monitor the effectiveness of systemic therapies for mCRC; here we report on the association of CEA and CA19-9 changes while on treatment with clinical outcomes in pts from the SLI. Methods: Pts in the SLI received the triplet of ENCO 300 mg QD + BINI 45 mg BID + CETUX 400 mg/m2 (initial dose) then 250 mg/m2 QW in 28-day cycles. Pts were evaluated for safety, radiographic response, and change in tumor markers CEA and CA19-9. Results: 30 pts were treated. The triplet was generally well tolerated, and adverse events were consistent with known BRAF, MEK, and EGFR inhibitor toxicities. The rate of severe skin toxicities (grade 3/4) was lower than generally observed for CETUX in mCRC. Of the 29 pts with a BRAFV600E mutation, the median time on study treatment was 5.6 mo (range, 1.0–9.3 mo), and 22 (76%) remained on study treatment at the time of data cutoff. The confirmed overall response rate (ORR) was 41%, with 1 complete and 11 partial responses. In addition, 9 pts had prolonged stable disease (SD) up to 9.3 mo.CEA and CA19-9 were analyzed in 28 pts. CEA and CA19-9 decreased in 96% and 82% of these pts, respectively. Among 15 pts with treatment duration ≥5.6 mo, median/mean % decreases were 97%/79% for CEA and 92%/82% for CA19-9 in confirmed responders (n=6). Respective decreases in pts with prolonged SD (n=9) were similar: 84%/68% for CEA and 89%/68% for CA19-9. Updated safety, efficacy, and tumor marker results will be provided. Conclusions: ENCO + BINI + CETUX is generally well tolerated and has encouraging clinical activity in BRAFV 600E mCRC, with a confirmed ORR of 41%. In pts with study treatment duration ≥5.6 mo, the tumor markers CEA and CA19-9 decreased markedly and to the same degree in responders vs pts with prolonged SD, providing additional evidence of the meaningful clinical activity of this regimen. Clinical trial information: NCT02928224.

612 Background: mCRC is a heterogeneous disease leading to possible disparate responses among lesions in a single pt. This study assesses the heterogeneity of lesion responses and evaluates the prognostic value of LBR12 and its mortality risk discrimination beyond RECIST responses. Methods: Pts with ≥ 2 lesions and no new lesions at 12 weeks (wks) were eligible. For each pt, after 12 wks of Rx, each lesion was categorized as progressive disease (L-PD: ≥20% increase in the longest diameter [LD]), partial response (L-PR: ≥30% decrease in LD), or stable disease (L-SD: neither L-PD nor L-PR). LBR12 was defined, per patient, by the combination of lesion responses: homogeneous LBR12 (L-PD, L-SD, L-PR only) and heterogeneous LBR12 (mixture of L-PD/L-SD, L-PD/L-PR, L-SD/L-PR). LBR12 and overall survival (OS) were correlated using stratified multivariate Cox models after adjusting for age, gender, and ECOG PS. Results: Among 9,092 mCRCs (Rx: chemo alone 44%; chemo + VEGF inhibitor [VEGFi] 42%; chemo + EGFR inhibitor [EGFRi] 10%) from 16 1st-line studies. Median OS: 2.2 years. Per RECIST at 12 wks, CR 0%; PR 36.1%; SD 60.9%; PD 3.0%. Responses in 52% were heterogeneous (Table). VEGFi and EGFRi treated pts had the highest rate of L-SD/L-PR (45%) and L-PR only (22%) status, respectively. Median OS increased monotonically across pts with more L-PRs and fewer L-PDs (Table). Pts with L-SD/L-PR status, among which 51% had SD per RECIST, had longer OS than those with L-SD only status (HRadj.= .81, padj.< .0001), but shorter OS than those with L-PR only status (HRadj.= 1.46, padj.< .0001). Pts with L-PD/L-SD status, among which 71% were SD per RECIST, had shorter OS than those with L-SD only status (HRadj.= 2.22, padj.< .0001). These associations were consistent across treatment regimens. Conclusions: The lesion-based response captures the heterogeneity of within pt lesion responses and provides refinement in predicting outcome beyond RECIST response at 12 wks. [Table: see text]

611 Background: Regorafenib is an oral multikinase inhibitor with survival benefit in refractory mCRC patients (pts). Toxicities such as Palmar-plantar erythrodysesthesia syndrome (PPES), fatigue and hypertension (HTN) have limited its use. Despite absence of supportive data, various dosing or interval scheduling have been implemented into clinical practice. Methods: A randomized phase II study of regorafenib dose-escalation (Arm A: 80 mg/day, weekly dose escalation if no significant drug-related toxicities, up to 160 mg/day) vs. standard dose (Arm B: 160 mg/day) in pts with mCRC for 21 days of a 28-day cycle. Pts were randomized 1:1:1:1 to arms A1 and B1 (Pre-emptive Clobetasol for PPES); A2 and B2 (Reactive Clobetasol). The primary endpoint was the proportion of patients who completed 2 cycles of treatment and initiated the 3rd in Arm A (Pooled A1 + A2) vs. Arm B (Pooled B1 + B2). Superiority for Arm A was to be declared if the one-sided p-value calculated using Fisher’s exact method was less than 0.2. Results: From June 2015 to June 2017, 123 pts were randomized with 116 (A = 54, B = 62) evaluable for the primary endpoint. Demographic data were well balanced with overall median age of 61yrs (range: 29-81), M/F (61/39%) and ECOG PS 0/1 (37/63%) and KRAS MT/WT/UNK (47/44/9%).The study met its primary endpoint with 43% of pts on Arm A initiating the 3rd vs. only 25% of pts Arm B [one-sided p-value 0.028]. Median Overall Survival (OS) was improved in Arm A vs. Arm B (9.0 mos vs. 5.9 mos; p = 0.094). Median Progression Free Survival (PFS) was 2.5 mos for Arm A vs. 2.0 mos for Arm B (p=0.553). Overall rates of grade 3/4 toxicity were more favorable for Arm A vs. Arm B (% PPES 15 vs. 16, HTN 7 vs. 15 and fatigue 13 vs. 18, respectively). Multiple QOL parameters were improved in A vs. B primarily at week 2 of the first cycle. Conclusion: A strategy with weekly dose escalation of regorafenib from 80 mg to 160 mg/day was found to be superior to a starting dose of 160 mg/day. These results establish a new standard for optimizing regorafenib dosing. Further data on outcomes of preemptive vs. reactive clobetasol strategies are undergoing analysis and will be presented later. Clinical trial information: NCT02368886.