Predictive and prognostic features of metastatic colorectal cancer arising from the transverse colon: A pooled analysis of the CCTG/AGITG CO.17 and CO.20 randomized trials

124

Background: Primary tumour location is predictive of anti-EGFR benefit and prognostic in metastatic colorectal cancer (mCRC). Transverse colon cancers are often categorized as right sided, but the optimal cut point is unclear. Canadian Cancer Trials Group (CCTG)/Australasian Gastro-Intestinal Trials Group ( AGITG) CO.17 compared Cetuximab (Cet) vs. best supportive care (BSC) in mCRC. CCTG/AGITG CO.20 studied the addition of Brivanib Alaninate to Cet in pre-treated KRAS wildtype (WT) mCRC. We investigated the predictive and prognostic features of transverse colon primary location in a pooled cohort from these trials. Methods: Data from patients with RAS WT mCRC from CO.17 and KRAS WT mCRC from CO.20 randomized to cetux were analyzed for treatment outcomes according to location - right, transverse and left. The cecum to transverse colon was considered right sided, while the splenic flexure to rectum was considered left sided. Results: 553 patients were included, 201 (36.3%) from CO.17 and 352 (63.7%) from CO.20. Primary site distribution was: 32 (5.8%) transverse, 101 (18.3%) right and 420 (75.9%) left. On multivariate analysis from 457 (82.6%) patients treated with Cet, left side was associated with superior OS (HR, 0.40; 95% CI, 0.24-0.68, p=0.0006) and PFS (HR, 0.48; 95% CI,0.29-0.79, p=0.004) compared to transverse colon. No significant difference was noted in OS (HR, 0.74; 95% CI, 0.41-1.31, p=0.30) and PFS (HR, 0.79; 95% CI, 0.46-1.36, p=0.40) between right side versus transverse colon. Sidedness was not associated with prognostic difference in OS or PFS in the 96 (17.4%) patients receiving BSC alone. Outcomes according to primary site and treatment are shown. Conclusions: Transverse mCRC has comparable prognostic and predictive features to right sided mCRC. In keeping with previous studies, left side was predictive of greater Cet benefit and presented better overall prognosis when single agent Cet was used after 5-FU, oxaliplatin and irinotecan. [Table: see text]

Bevacizumab in first-line therapy in lung metastases of colorectal cancer: An ARCAD pooled analysis

118

Background: Anti-VEGF is widely used in the treatment (trt) of metastatic colorectal cancer (mCRC). Only studies with bevacizumab (BEV) have shown survival benefit (bnf) in first line trt. The magnitude of bnf might differ based on the metastatic (met) site and the chemotherapy regimen (CTR) with which BEV is partnered. ARCAD database contains individual patient data (IPD) of randomized trials that evaluated BEV+ CT. In this pooled analysis, we aimed to evaluate BEV bnf in mCRC with lung metastases (mets) either as single or multiple sites. Methods: IPD from four trials (AVF2107g, N016966, AVF2192g, AGITG) comparing CT +/- BEV were pooled. The primary endpoint, overall survival (OS), was estimated using Kaplan-Meier method and prognostic value of lung mets was evaluated by stratified Cox models according to number and type of met sites and CTRs, oxaliplatin or irinotecan (OX/IRI) based. The predictive bnf of BEV was evaluated by interaction test (int) between trt and lung mets status in subgroups and considered as significant (sig) with a P < 0.1. Results: 2728 patients (pts) with known met sites and survival data were pooled. 1020 pts had single met site, 133 had only lung mets. 1708 pts had multiple met sites, 1008 had lung mets. Pts characteristics were well balanced. Sig OS bnf of BEV was observed in the whole population. In pts subgroup according to the presence or absence of lung mets, sig bnf of BEV were observed with a non-sig int ( Pint=.590). Non-sig bnf of BEV was observed in pts with single site regardless of met site (lung or no lung) or CTR. Sig bnf of BEV was observed in pts with multiple sites without lung mets whatever the CTRs. While sig bnf of BEV was observed in pts with multiple sites with lung mets, we found a sig int between BEV and OX/IRI-based regimens ( Pint=.022). The bnf of BEV was observed with IRI-based regimen but not in OX-based regimen. The bnf of BEV appears greater in multiple sites without lung mets than with lung mets with a sig stratified log-rank test ( PLRT<.001). Conclusions: In pts with multiple sites mCRC, a statistically sig OS bnf of BEV added to CT was observed mainly among pts without lung mets. The overall effect of CT partner choice when combined with BEV can be different. In pts with single site, BEV did not seem to improve OS but the evaluation of efficacy of BEV in presence or absence lung mets was based on small number of pts and needs to be evaluated in trials with larger pts sample, especially trials including pts with single site lung mets. [Table: see text]

Phase I study of PTM-101 as neoadjuvant therapy for borderline resectable or locally advanced pancreatic ductal adenocarcinoma: A trial in progress

TPS775

Background: While there have been tremendous advances in cancer treatment, critical challenges remain including limited ability of drugs to successfully reach the tumor, short half-life, and low retention rate on site. Local control of non-metastatic pancreatic adenocarcinoma (PDAC) remains a major challenge. Up to 40% of patients present with locally advanced and borderline resectable anatomy, for whom enhanced local downsizing of disease could improve symptoms and increase overall survival (OS). Targeted therapies with reduced systemic toxicity are needed for the treatment of PDAC since current therapies have not provided meaningful advances. PTM-101 is a paclitaxel-impregnated absorbable product which is designed for direct, sustained release of the therapeutic agent at the tumor site. Preclinical animal studies demonstrate that PTM-101 results in enhanced drug levels in the tumor compared with comparable systemic paclitaxel dosing leading to tumor reduction, metastasis inhibition and survival benefit (Indolfi et al, 2016). Large animal (i.e. pigs) and human cadaver studies show that PTM-101 can successfully be deployed to the peritumoral pancreatic surface by a standard laparoscopic procedure. Further, large animal studies show no evidence of neutropenia, pancreatitis, severe fibrosis or scarring, or infection after placement of PTM-101. Methods: This Phase I trial will assess the addition of PTM-101 prior to mFOLFIRINOX in 6 subjects with newly diagnosed borderline resectable or locally advanced PDAC. The primary objective is to assess the safety, toxicity and feasibility of a single administration of PTM-101. It is hypothesized that PTM-101 will be readily implanted during diagnostic laparoscopy and will result in clinically meaningful delivery of paclitaxel directly towards the tumor area with good tolerance and minimal local systemic exposure of drug. Patients enrolled and treated on study will be monitored closely for local and systemic toxicities as well as preliminary signals of efficacy. Enrollment is in progress and 3 patients have been enrolled and completed prospective follow up at the time of abstract submission. Clinical trial information: ACTRN12621000881831 .

INTEGRATE IIa: A randomised, double-blind, phase III study of regorafenib versus placebo in refractory advanced gastro-oesophageal cancer (AGOC)—A study led by the Australasian Gastro-intestinal Trials Group (AGITG)

LBA294

Background: AGOC has limited options after second-line therapy. Regorafenib (Rego), an oral multi-targeted tyrosine kinase inhibitor (TKI) targeting angiogenic, stromal and oncogenic receptor TKs, prolonged progression free survival (PFS) versus placebo (PBO) across all regions/subgroups in the INTEGRATE phase 2 randomised trial (JCO 2016 43(23):2728-2735). INTEGRATE IIa was designed to examine if Rego improves overall survival (OS). Methods: Double-blind placebo-controlled phase 3 trial comparing Rego + best supportive care (BSC) vs PBO + BSC using 2:1 randomisation, stratified by tumour location (GO junction vs gastric), geographic region (Asia vs rest of world), prior VEGF inhibitors (Y/N). Eligibility criteria: histologically/cytologically confirmed AGOC, evaluable metastatic/locally advanced disease, failure/intolerance of ≥ 2 prior lines of therapy with a platinum agent + fluoropyrimidine. Primary objective: OS in the whole study population. OS among Asian sub-population is a key secondary objective. Target of at least 221 events from 250 patients provides 80% power to detect an OS hazard ratio (HR) of 0.67. Pooled OS analysis incorporating INTEGRATE phase 2 data is also planned. Secondary endpoints include PFS, objective response rate, safety and quality of life. Results: 251 patients enrolled (Oct16 - Sep21) from 5 countries:157 from Asia (Korea, Taiwan, Japan);169 Rego and 82 PBO. After 238 events, median OS (in months) for Rego vs PBO was 4.5 vs 4.0 (HR 0.70 [95%CI: 0.53 to 0.92]; p = 0.011) in the whole study population, with a 12 mo survival of 19% vs 6%. Median PFS was 1.8 v 1.6 (HR = 0.52; [95%CI: 0.40-0.69]; p = < .0001). After pre-planned adjustment for multiplicity, there were no statistically significant differences across regions (Asia versus non-Asia) or other pre-specified subgroups. Pooled analysis median OS was 5.0 v 4.1 (HR 0.69 [95% CI:0.56 to 0.87]; p = 0.001). Rego toxicity was similar to previously reported. Conclusions: Rego improves survival compared with PBO in advanced refractory AGOC, offering a new treatment option. This result creates a therapeutic platform for combination studies. INTEGRATE IIb is an ongoing international randomised Phase 3 trial in pre-treated patients with AGOC comparing Rego + nivolumab to standard chemotherapy (NCT0487936). Clinical trial information: NCT02773524 .

Mutational heterogeneity of imatinib resistance and efficacy of ripretinib vs sunitinib in patients with gastrointestinal stromal tumor: ctDNA analysis from INTRIGUE

397784

Background: Ripretinib, a switch-control tyrosine kinase inhibitor (TKI), is indicated for patients (pts) with gastrointestinal stromal tumor (GIST) who received prior treatment with ≥3 TKIs, including imatinib. Sunitinib is approved for advanced GIST after imatinib failure. Circulating tumor DNA (ctDNA) analysis may provide insight into the efficacy of these agents in second-line advanced GIST. Here, we present exploratory baseline ctDNA results from INTRIGUE. Methods: INTRIGUE is an open-label, phase 3 study that enrolled adult pts with advanced GIST who progressed on or had intolerance to imatinib (NCT03673501). Randomization was 1:1 to ripretinib 150 mg once daily (QD) or sunitinib 50 mg QD (4 wks on/2 wks off). Baseline peripheral whole blood was analyzed by Guardant360, a 74-gene ctDNA next-generation sequencing (NGS)-based assay. Only KIT mutations are reported here. Results: Of 453 pts in the overall intent-to-treat (ITT) population, 362 (80%) samples were analyzed. ctDNA was detected in 280/362 (77%), with KIT mutations detected in 213/280 (76%). Common resistance mutations were in the KIT activation loop (AL; exons 17/18; 89/213, 42%) and ATP-binding pocket (ATP-BP; exons 13/14; 81/213, 38%). Efficacy in pts with detectable ctDNA in the KIT exon 11 and overall ITT populations was consistent with the primary analysis based on tumor data used for randomization. Pts with KIT exon 11 + 17/18 (−9/13/14) mutations had superior progression-free survival (PFS), objective response rate (ORR), and overall survival (OS) with ripretinib vs sunitinib, whereas pts with exon 11 + 13/14 (−9/17/18) mutations had better PFS, ORR, and OS with sunitinib vs ripretinib (Table). Subgroup safety profiles were consistent with the primary analysis. Conclusions: While KIT ATP-BP mutations predicted clinical benefit from sunitinib vs ripretinib, pts harboring resistance mutations in the KIT AL derived meaningful clinical benefit from ripretinib but not sunitinib. This study demonstrates the value of ctDNA NGS-based sequencing of the complex landscape of KIT mutations to predict the clinical benefit of ripretinib or sunitinib as second-line therapy in pts with advanced GIST. Clinical trial information: NCT03673501 . [Table: see text]

Patient reported outcomes and tolerability in patients receiving ripretinib versus sunitinib after imatinib treatment in INTRIGUE: A phase 3 open-label study

11541

Background: Ripretinib (R) is a switch-control tyrosine kinase inhibitor (TKI) indicated for the treatment of patients (pts) with advanced gastrointestinal stromal tumor (GIST) after prior treatment with ≥3 TKIs. In the INTRIGUE study (NCT03673501) there was no significant difference in median PFS (primary endpoint) between R and sunitinib (S). We present exploratory analyses of tolerability data and selected pt reported outcomes (PROs). Methods: Pts were randomized 1:1 to R 150 mg QD or S 50 mg QD 4 weeks on/2 weeks off.Dose modification was allowed for toxicity management. The event of interest was severe or life-threatening (grade ≥3) treatment-related adverse event prior to progression (sTRAE). Days with at least one sTRAE were summed for all treated pts and for pts with ≥1 sTRAE event. PROs were assessed using questions from EORTC QLQ-C30 and Dermatology Life Quality Index (DLQI) at cycle 1 (C1) day 1 (D1), D15, and D29; D1 and D29 of all other cycles; as well as at end of treatment. Differences in PRO scores between baseline and later assessments were calculated across visits. Long-term data will be presented. Results: Pts receiving R (n = 223) versus (vs) S (n = 221) experienced fewer sTRAEs (24% vs 51%, respectively). For all treated pts, the mean time with sTRAEs was 11 days for R and 42 days for S (ratio 0.27, P<0.0001). For pts with ≥1 sTRAE, the mean number of days with a sTRAE was 48 days for R vs 81 days for S (ratio 0.59, p = 0.037). Completion of PRO assessments across the two treatment arms was similar (baseline: R [n = 199], S [n = 199]; C1 D29: R [n = 167], S [n = 177]). Significant differences in self-reported functioning and symptoms were observed by C1 D29. For PROs relating to commonly reported sTRAEs, except constipation, pts in the R arm reported better outcomes than pts in the S arm. Pts in the R arm reported significantly (p<0.05) less decline compared to baseline in pt-reported role function as well as less increase, or improvement, in symptoms of fatigue, appetite loss, diarrhea, nausea/vomiting, and pain vs pts in the S arm. Moderate or severe effect of skin toxicity on pt life, as measured by DLQI in the R arm (n = 165) and in the S arm (n = 175), was observed in 6.6% of pts in the R arm vs 14.8% of pts in the S arm (p = 0.015). Conclusions: In the INTRIGUE study the total number of days with sTRAEs was fewer for pts receiving R vs S. Pts in the R arm also reported significantly less decline in pt-reported role function and less increase in symptoms related to commonly reported sTRAEs, except constipation, vs pts in the S arm. Medical writing provided by Costello Medical. Clinical trial information: NCT03673501.

Response to epithelial growth factor receptor inhibitor (EGFRi) treatment in patients with early-onset, treatment-naïve metastatic colorectal cancer (mCRC): An ARCAD database analysis

3572

Background: Early onset colorectal cancer (eoCRC: disease diagnosed < 50) has been increasing over the past 2 decades. Currently, standard treatment recommendations for eoCRC patients (pts) with metastatic disease does not differ from late-onset CRC (loCRC) pts although outcomes data in eoCRC pts is limited. Methods: Individual patient data on 5,761 treatment-naive metastatic eoCRC pts was pooled from 8 phase II and III randomized EGFRi studies (2000 - 2012) from the ARCAD mCRC database. The distribution of demographics, clinicopathological features, and biomarkers were summarized by age groups. Progression-free survival (PFS) was compared between age groups by stratified Cox models, adjusting for potential confounders. Predictive value of age group was evaluated by testing interaction effect between treatment and age variables based on a subset of trials with concurrent randomizations between regimens with and without EGFRi Results: eoCRC (n=756) were more evenly distributed between gender, had improved performance status (PS), increased likelihood of metastatic resection, and distant lymph node metastasis, but were less likely to have lung metastasis or KRAS mutation compared to loCRC (n=5,005, table 1). eoCRC and loCRC patients had similar distribution of primary tumor sidedness, primary resection, liver and/or peritoneal involvement, number of metastatic sites involved, and BRAF mutations (MT). No difference in PFS for eoCRC versus loCRC pts was noted (7.8 vs. 7.9 months [M], adjusted hazard ratio [HRadj], 1.02, 95% confidence interval [CI], 0.93-1.11). Among pts with KRAS wild type (WT) and left sided primary tumors, univariable analysis of EGFRi demonstrated improved mPFS in loCRC (9.9 vs 8.5M, HR = 0.74, p<0.001), but this benefit was not seen in eoCRC (8.3 vs 8.9 months, HR 1.20, p=0.36). The same pattern was observed upon multivariable analysis (Table). Conclusions: In our pooled analysis, EGFRi + chemotherapy significantly improved PFS in treatment-naïve loCRC patients but not in left sided, KRAS WT, eoCRC patients. Further validation in an independent cohort is warranted. [Table: see text]

First-line (L1) therapy targeting EGFR in lung metastases (mets) of colorectal cancer (mCRC): An ARCAD pooled analysis

3578

Background: Monoclonal antibodies (mab) targeting EGFR are recommended in L1 treatment (trt) for mCRC in patients (pts) with RAS wild-type (WT) tumor and primary left CRC. ARCAD database contains individual data of randomized trials that evaluated anti-EGFR mab plus chemotherapy (CT). In this analysis we aimed to evaluate anti-EGFR benefit in mCRC with lung mets, either as single site or multiple sites. Methods: Individual pts data from four trials (PRIME, CRYSTAL, COIN, OPUS) comparing CT +/- anti-EGFR were pooled. KRAS status was not required at inclusion to these studies. The primary endpoint, overall survival (OS), was estimated using Kaplan-Meier method, prognostic value of lung mets was evaluated by stratified Cox models in pts groups defined by KRAS status. The predictive value was evaluated by interaction test (Int) between trt and lung mets status in pts group defined by KRAS status and considered as significant with a P < 0.1. Results: 3681 pts with known KRAS status were included, 2171 WT and 1510 mutant (MT). Pts characteristics were well balanced. Significant median OS benefit of anti-EGFR was observed in the whole KRAS WT population and in the left colon and rectum subgroup but not in the right colon subgroup. In pts with KRAS WT single site mets, a non-significant benefit of anti-EGFR was observed only among pts without lung mets (N = 642). In pts with lung single site mets (N = 129), a significant benefit ( P= 0.018) in the KRAS MT population (N = 55) was observed, but Int was non-significant ( P =0.157). In pts with KRAS WT and multiple without lung mets sites (N = 673), no benefit of anti-EGFR was observed and Int was significant ( P= 0.054). Pts with KRAS MT multiple sites with (N = 656) or without (N = 397) lung mets, had no benefit of anti-EGFR. The same findings were found in the left primary pts and in the two fluoropyrimidine backbone. PFS analyses confirm the OS results. Conclusions: In this ARCAD analysis pts with lung mets as a single site appear to benefit from anti-EGFR L1 therapy in case of KRAS MT. This unexpected result based on a limited sample size cannot be explained on the knowledge of anti-EGFR therapy. Furthermore, pts with multiple mets sites have a benefit of anti-EGFR therapy only in the presence of lung mets even in KRAS WT left primary tumor. These findings need further confirmation and may initiate the search for a specific molecular phenotype associated with lung mets in CRC pts. [Table: see text]

Cancer diagnosis, cancer treatment, and association with cardiovascular disease in older adults: Results from ASPREE

12086

Background: New treatments and early detection measures have led to declines in cancer mortality rates and a growing population of cancer survivors at risk of short- and long-term effects of cancer and cancer treatment (C&CT), including cardiovascular disease (CVD). Although shared risk factors may contribute, several C&CT-related mechanisms including inflammation, treatment-related cardiotoxicity, and coagulation disorders may play a role. There are several studies exploring the link between C&CT and CVD; however, many do not examine risk stratified by cancer type or disease extent, nor investigate the impact of different treatment modalities. Methods: This analysis utilized data from the ASPirin in Reducing Events in the Elderly (ASPREE) trial, an international, multi-center, double-blinded randomized controlled trial that investigated the benefits and risks of aspirin in healthy older people. Multivariate time-dependent Cox regression models (adjusted for clinically significant factors including age, gender, smoking, and metabolic disease) were used to investigate the impact of C&CT on myocardial infarction, stroke, hospitalization for heart failure, and a composite endpoint combining these. Crude incidence rates were estimated using a competing risks regression model. Subgroup analysis was performed by metastatic status, cancer type, and treatment modality. Results: Of the 19,114 ASPREE participants (56% female; median age 75.1 years; median follow up 4.7 years), 1,933 received a post-randomisation cancer diagnosis. Participants with cancer had a greater rate and risk of CVD than those without cancer (15.3 per 1000 person-years (/1000pyrs] vs 10.5/1000pyrs, respectively; Hazard Ratio [HR] = 1.70, 95% Confidence Interval [CI] 1.32-2.10). The greatest increase in risk was seen for hospitalization for heart failure (HR 2.00, 1.18-3.38, 95% CI 1.18-3.38), although increases in risk were also seen for myocardial infarction, all-stroke, and ischaemic stroke. In subgroup analysis by cancer type, blood cancer (HR 2.33, 95% CI 1.25-4.36), lung cancer (HR 2.76, 95% CI 1.23-6.19), and melanoma (HR 1.97, 95% CI 1.02-3.82) were associated with an increased risk of composite CVD. ‘Any cancer treatment’ conferred increased risk of hospitalisation for heart failure (HR 1.78, 95% CI 1.15-2.75), although individual treatment modalities, including cytotoxic chemotherapy, targeted therapy, and radiotherapy conferred increased risks of various cardiovascular outcomes. Conclusions: Our findings indicate that both cancer and anti-cancer treatment confer risk for CVD in the elderly, the magnitude of which varied depending on cancer type and treatment modality. Given the implications of cardiovascular events for quality of life and mortality, these results support the integration of CVD screening and management into routine care for cancer survivors.

Australasian Gastrointestinal Trials Group (AGITG) CONTROL NET Study: 177Lu-DOTATATE peptide receptor radionuclide therapy (PRRT) and capecitabine plus temozolomide (CAPTEM) for pancreas and midgut neuroendocrine tumours (pNETS, mNETS)—Final results

4122

Background: CAPTEM is an accepted regimen for patients (pts) with advanced pNETs. Single agent PRRT is now a standard of care for progressive WHO Grade 1/2 mNETs. High activity was seen with PRRT/CAPTEM in a single arm Phase I/II trial. This study aims to determine the activity of combining CAPTEM with PRRT in mNETs and pNETs pts. Methods: Non-comparative randomised open label parallel group phase II trial with 2:1 randomisation to PRRT/CAPTEM (experimental arm) vs. PRRT (mNETs control) and CAPTEM (pNETS control). PRRT/CAPTEM: 7.8GBq 177Lu Octreotate (Lutate) given intravenously (IV) on day 10 every 8 weeks for 4 cycles, with concurrent oral capecitabine 750mg/m2 b.i.d. days 1-14 and temozolomide 75mg/m2 b.i.d. days 10-14 every 56 day cycle, up to 4 cycles. PRRT alone: 7.8GBq 177Lu Octreotate (Lutate) given intravenously (IV) on day 1 every 8 weeks for 4 cycles. CAPTEM alone: Oral capecitabine 750mg/m2 b.i.d. days 1-14 and days 29-42; Oral temozolomide 75mg/m2 b.i.d. days 10-14 and 38-42 every 56 day (8w) cycle. Primary endpoint: Progression free survival (PFS). mNETS: At 15 months, assuming PFS 66.4% in control arm; target PFS ³ 80%; pNETS: At 12 months, assuming PFS 60% in control arm; target PFS ³ 75%. Secondary endpoints: Objective tumor response rate (complete or partial) (OTRR), overall survival (OS), adverse events (AEs). Results: 75 pts enrolled (Dec 2015 – Nov 2018): mNETs 33 PRRT/CAPTEM, 14 PRRT, median follow up (mFU) 60.3 months; pNETS 19 PRRT/CAPTEM, 9 CAPTEM, mFU 57.5 months (mo). Late Grade 3/4 haematologic AEs: mNETS: 2/32 (6%) PRRT/CAPTEM pts and 4/13 (31%) PRRT pts. Events included myelodysplastic syndrome (40 mo), leukaemia (60 mo), pancytopenia (50 mo), anaemia (32 mo), thrombocytopenia (7 mo). No late haematologic G3/4 AEs were reported in the pNETS cohort. No late renal toxicity was identified in all study arms. Conclusions: CONTROL NETs is the first randomized trial to demonstrate efficacy for PRRT in pNETs, in addition to a standard of care. Extended follow up confirms durable CAPTEM/PRRT activity, with superior PFS in pNETs. Late haematologic toxicity was seen in both mNET PRRT arms but was not higher with additional CAPTEM. The activity of CAPTEM/PRRT in pNETs should be tested in the phase III setting. Clinical trial information: ACTRN12615000909527. [Table: see text]

Locally advanced esophageal cancer: Evaluation of prognosis by assessment of the “yp” stage based on the neoadjuvant regimen received

356

Background: Neoadjuvant treatment in the form of chemoradiotherapy (nCRT) or chemotherapy (nCT) for resectable oesophageal cancer is the standard of care and improves R0 resection rates and overall survival (OS). The recently reported Neo-AEGIS study demonstrated ongoing equipoise between neoadjuvant chemoradiotherapy and peri-operative chemotherapy for oesophageal adenocarcinoma. There is limited data evaluating the prognostic outcomes by evaluation of the pathological stage after resection (yp stage) based on the neoadjuvant regimen received. The aim of this study was to look at the survival outcomes of patients with oesophageal cancer who received neoadjuvant therapy and to analyze the prognostic significance of pathological stage at surgery (“yp” stage) compared to the clinical stage based on the neoadjuvant therapy received. Methods: This was a single- centre, retrospective study over a fifteen-year period between 2005 and 2019. Consecutive patients with oesophageal and GOJ cancers that underwent resection post neoadjuvant treatment were included. The unit policy was to treat adenocarcinoma of the oesophagus and GOJ with perioperative chemotherapy until 2015 after which it was switched to neoadjuvant chemoradiotherapy in the form of the CROSS protocol. Results: Neoadjuvant treatment with either neoadjuvant chemoradiotherapy (nCRT) or neoadjuvant chemotherapy (nCT) prior to surgical resection was undertaken in 137 patients with resectable oesophageal and GOJ cancers between the years 2005 and 2019. The median age was 65 and 79% of the cohort was male. The majority of tumours were located in the lower oesophagus or GOJ and 96 patients in the cohort were clinical stage 3. 126 patients had adenocarcinoma and 11 patients had squamous cell carcinoma. 72 patients received nCT, and 65 patients received the nCRT. The “yp” stage showed 26 patients achieved a complete pathological response (CPR) and 47 patients were down-staged. The clinical stage was not a predictor of overall survival (p = 0.65). On the other hand, the “yp” stage was a significant predictor of survival (p < 1×10-8). In patients who received nCRT, 18 achieved a complete pathological response compared to 8 patients who had received nCT. Patients who received nCRT showed improved survival compared to patients who received nCT (p = 0.043). Patients who achieved a CPR with neoadjuvant chemotherapy had an OS of 100% compared to OS of 80% in patients who received nCRT (p = NS). Neoadjuvant chemoradiotherapy was associated with less loco-regional recurrences and distant recurrences compared to neoadjuvant chemotherapy. Conclusions: The “yp” stages, as well as down-staging with neoadjuvant therapy are strong predictors of survival. A greater proportion of patients achieved down-staging and CPR following neoadjuvant chemoradiotherapy compared to neoadjuvant chemotherapy.

Trajectories of body weight change and survival among mCRC patients treated with systemic therapy: Pooled analysis from the ARCAD database

80

Background: Higher baseline body mass index is associated with improved survival in metastatic CRC (mCRC). Whether weight gain or loss after mCRC diagnosis is associated with survival remains largely unknown. Methods: We analyzed individual patient data from 3504 patients with previously untreated mCRC enrolled in five phase III randomized trials (AVF2017g, AVF2192g, CRYSTAL, N9741, OPUS) conducted between 2000 and 2006. Weight measurements were prospectively collected at 3 months after diagnosis and then up to 5 years. Patients were categorized into three groups based on the percent weight change at 3 months: stable weight or gain, weight loss up to 5% of baseline weight, and ≥5% weight loss of baseline weight. Cox models were used to assess the prognostic associations of weight change at 3 months with overall survival (OS) and progression-free survival (PFS), adjusting for baseline BMI, age, sex, performance score, chemotherapy backbone (oxaliplatin vs. irinotecan), and biologics type (cetuximab vs. bevacizumab). Sub-analyses included Cox models adjusted for additional clinical-pathological factors (primary tumor sidedness [right colon vs. left colon-rectum], and BRAF status; N=1,511). Results: Median percent weight change at 3 months was -0.5% (IQR -4.0 to+1.6%). OS was better in patients with weight stability or gain than in those with weight loss (up to 5% or ≥5%; (Table). Results were consistent for PFS for patients with ≥5% weight loss of baseline weight, as well as for sub-analyses. Conclusions: Patients losing weight during the first 3 months of systemic therapy for metastatic colorectal cancer have significantly shorter overall survival than those with stable or increasing weight. Degree of weight loss is proportional to the observed increased risk of death and remains evident among underweight, normal weight and obese individuals. Further studies examining possible usefulness of on-treatment early weight loss as a novel intermediary end-point are needed.[Table: see text]

INTRIGUE: A phase III, randomized, open-label study to evaluate the efficacy and safety of ripretinib versus sunitinib in patients with advanced gastrointestinal stromal tumor previously treated with imatinib

359881

Background: Sunitinib is approved for advanced gastrointestinal stromal tumor (GIST) after imatinib failure. Ripretinib, a broad-spectrum KIT and PDGFRA switch-control tyrosine kinase inhibitor (TKI), is indicated for the treatment of adult patients (pts) with GIST who received prior treatment with 3 or more TKIs, including imatinib. We compared the efficacy and safety of ripretinib vs sunitinib in pts with advanced GIST who progressed on or were intolerant to imatinib. Methods: This multicenter, global, randomized, open-label phase 3 study (NCT03673501) enrolled adult pts with GIST who progressed on or had intolerance to imatinib. Pts were randomized 1:1 to ripretinib 150 mg once daily (QD) or sunitinib 50 mg QD (4 wks on/2 wks off). Randomization was stratified by KIT mutational status and imatinib intolerance. The primary endpoint was progression-free survival (PFS) by independent radiologic review (IRR) using modified RECIST version 1.1. Key secondary endpoints were objective response rate (ORR) by IRR and overall survival (OS). Hierarchical testing was performed for primary and key secondary endpoints in a prespecified sequence; testing pts with a KIT exon 11 primary mutation (Ex11 intention-to-treat [ITT] population) preceded the all-patient (AP) ITT population. Data cutoff was 1 Sep 2021; final analyses of PFS and ORR and the first interim analysis of OS were conducted. Results: A total of 453 pts were randomized to ripretinib (n = 226; Ex11 ITT, n = 163) or sunitinib (n = 227; Ex11 ITT, n = 164). Median age was 60 yrs (range 18–88) and most pts were white (66.2%) males (62.0%). PFS was not statistically different between ripretinib and sunitinib in the Ex11 ITT (hazard ratio [HR] 0.88, 95% CI 0.66, 1.16; P = 0.36; median 8.3 vs 7.0 mos) or in the AP populations (HR 1.05, 95% CI 0.82, 1.33; P = 0.72; median 8.0 vs 8.3 mos). ORR was numerically higher for ripretinib vs sunitinib in the Ex11 ITT (23.9% vs 14.6%; difference 9.3%, 95% CI 0.7, 17.8; nominal P = 0.03) and AP ITT populations (21.7% vs 17.6%; difference 4.2%, 95% CI −3.2, 11.5; nominal P = 0.27). OS data was highly immature; median OS was not reached in either arm. Fewer pts in the ripretinib arm experienced Grade 3-4 (G3-4) treatment-emergent adverse events (TEAEs) vs sunitinib (41.3% vs 65.6%). Among G3-4 TEAEs with a difference ≥5% between arms, ripretinib had fewer events vs sunitinib (hypertension [8.5% vs 26.7%], palmar-plantar erythrodysesthesia [1.3% vs 10.0%], neutropenia [0% vs 6.3%], and neutrophil count decreased [0% vs 7.2%]). Conclusions: The PFS in both arms was longer than PFS achieved by sunitinib in its pivotal phase 3 trial. While the PFS for ripretinib did not meet the primary endpoint of superiority vs sunitinib, meaningful clinical activity and fewer G3-4 TEAEs were observed in pts with advanced GIST treated with ripretinib after imatinib failure. Clinical trial information: NCT03673501.

Phase III study of NUC-1031 + cisplatin versus gemcitabine + cisplatin for first-line treatment of patients with advanced biliary tract cancer (NuTide:121)

TPS4164

Background: Biliary tract cancer (BTC) is an aggressive disease with a poor prognosis. Gemcitabine + cisplatin (GemCis) is the accepted global standard of care (SoC), however key cancer resistance mechanisms associated with the transport, activation and breakdown of gemcitabine are known to limit its clinical activity across a range of tumor types, including BTC. NUC-1031 is a phosphoramidate transformation of gemcitabine designed to overcome these key resistance mechanisms and generate much higher levels of the active anti-cancer metabolite, dFdCTP, in cells. Promising efficacy has been observed with single-agent NUC-1031 in a phase I study in advanced solid tumors and in the phase Ib ABC-08 study of NUC-1031 + cisplatin for first-line treatment of advanced BTC. Of 21 patients enrolled in 2 dose cohorts (NUC-1031 625 mg/m2 or 725 mg/m2 + cisplatin 25 mg/m2 on Days 1 and 8 of 21-day cycle), 16 were considered to be efficacy evaluable. In this population, 1 patient had a CR and 6 patients had PRs, resulting in an ORR of 44% (7/16). This compares favorably to the 26% ORR reported for the SoC regimen. In addition, 6 patients had SD, resulting in a DCR of 81% (13/16). The combination was well tolerated with no unexpected AEs or DLTs. The recommended dose of NUC-1031 with cisplatin was 725 mg/m2. The tolerability profile, together with encouraging efficacy led to initiation of a global registrational study. Methods: NuTide:121 is a phase III, open-label, randomized study of NUC-1031 + cisplatin vs GemCis for first-line treatment of advanced BTC. Patients ≥18 years with histologically- or cytologically-confirmed BTC (including cholangiocarcinoma, gallbladder, or ampullary cancer), who have had no prior systemic chemotherapy for locally advanced/metastatic disease, are eligible. A total of 828 patients are being randomized (1:1) to either 725 mg/m2 NUC-1031 or 1000 mg/m2 gemcitabine, both with 25 mg/m2 cisplatin, administered on Days 1 and 8 of 21-day cycles. Primary endpoints are OS and ORR. Secondary endpoints include PFS, safety, PK and patient-reported quality of life. In addition to the final analysis, three interim analyses are planned. The study has passed an initial safety analysis, with no protocol changes required. NuTide:121 is being conducted at approximately 130 sites across North America, Europe and Asia Pacific. Clinical trial information: NCT04163900.

Multi-center phase 1 safety and efficacy study of nivolumab in renal transplant patients with metastatic malignancy

2567

Background: Organ Transplant Recipients (OTR) are generally excluded from trials of immune checkpoint inhibitors (ICI) due to the reported risk of allograft rejection. A recent systematic review of published case series includes only 65 cases. Transplant organ rejection rates of 41% are reported with cancer response rates of 39%. The majority of OTR treated with ICI have had reduction/cessation of immunosuppression (IS) prior to ICI. Isolated IS reduction is associated with organ rejection and therefore either IS manipulation alone and/or ICI could induce organ rejection episodes. Methods: Renal OTR with incurable cancer, for whom ICI would normally be used in the general population (without an organ transplant), were eligible if creatinine < 180 umol/l, no donor specific HLA antibodies and ECOG < 2. Treatment was with nivolumab (3mg/kg q 14 days for 5 doses, then 480 mg q 28 days), without manipulation of IS and pre-ICI-exposure alloimmune risk assessment. Treatment continued till progression, patient refusal, or graft rejection. Primary endpoint was rate of irretrievable renal graft rejection. Results: 15 patients (9 male:6 female; median age 66.6 years) were enrolled and treated with a median (range) 3(1-42) infusions and with median (range) follow-up of 128 (11-784) days. Tumour types included:1 melanoma; 2 renal tract; 1 hepatocellular carcinoma; 1 Merkel cell; 1 adenocarcinoma lung; 1 MSI high colorectal, 8 squamous cell carcinoma (SCC) head and neck. 2 patients experienced rejection; one at day 28 (2 infusions); one at day 36 (3 infusions). Both had SCC and have had a CR. One is on haemodialysis and alive at 2 years the other a creatinine 450 umol/l. Both rejections treated with steroid, plasma-exchange and anti-thymocyte-globulin (ATG). 1 patient (metastatic bladder cancer) experienced graft loss (at 300 days) due to ureteric-stent bleed and BK-nephritis indirectly related to nivolumab- this patient died of progressive disease at 65 days after nivolumab cessation. Median (range) progression free disease (PD) with ≥ 2 infusions was 300 (68-784+) days. There were 5 CR (1 MSI high colorectal, 4 SCC) median duration of response 13 months and 2 PR (1 SCC 1 bladder)- 1 without PD. Conclusions: In this interim analysis, rejection rates in OTR with incurable cancers treated with ICI was 2/15 (13%) when IS is maintained and there is pre exposure alloimmune assessment. The combined CR and PR rate was 7/15 (47%). Clinical trial information: 12617000741381.

Characteristics of patients (pts) and prognostic factors across treatment lines (TL) in metastatic colorectal cancer (mCRC): An analysis from the Analysis and Research in Cancers of the Digestive System (ARCAD) database

3575

Background: Pts with mCRC frequently receive ≥1 sequential treatment TL. Approximately 50%-60% of pts receive second-line (L2) and 20%-30% third-line (L3) regimens in routine practice. We investigated the pts clinical/tumor characteristics and their prognostic impact across TL. Methods: Data from 37,560 pts enrolled in 48 randomized trials (34 in first (L1), 9 in L2, and 5 in L3) were analyzed. Candidate variables (VAR) measured at enrollment were sex, age, body mass index, performance status (PS), bilirubin, hemoglobin (Hb), platelets (Pl), derived white blood cells-to-absolute neutrophil counts ratio (WBC/ANC), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), primary tumor location, and number and location of metastatic sites (MS). Missing data were imputed. VAR with significant value at all TL were selected to construct a prognostic score of overall survival (OS) in training set (TS, n=30,050; 80%). For each TL, the score was calculated as the sum on the estimations of the VAR’ coefficients from the common multivariate model; Cox’s model was used to define risk groups. The discrimination capability was assessed using the Harrell’s C-index. External validation was done in the validation set (VS, n=7,510; 20%). Results: A total of 26,974 pts in L1, 7,693 pts in L2 and 2,893 pts in L3 were analyzed. The following characteristics increased continuously over TL: ≥2 MS (57%, 72%, 82%), lung metastases (50%, 74%, 91%), lymph nodes metastases (51%, 61%, 80%), KRAS mutation (37%, 47%, 51%) and elevated ALP (46%, 52%, 61%). BRAF mutation decreased (9%, 7%, 5%). In L1 vs L3 trials, 70% vs 89% of patients had primary tumor resection, 10% vs 80% had at least one metastasectomy and 31% vs 78% had a late metachronous (>12 months) metastasis. 7 independent VAR were retained in the prognostic score (PS, Hb, Pl, WBC/ANC, LDH, ALP, and the number of MS); four pt groups with significantly different prognoses were defined (table). This score remained valid when excluding pts with PS 2. Third-line oral drugs (vs placebo) and subsequent line (L2/L1 or L3/L2) were effective in all prognostic groups. Conclusions: Clinical/tumor pt characteristics significantly varied over subsequent TL in patients included in randomized trials. The same prognostic model using practical clinical and biological variables can be used in all TL.[Table: see text]

Intra-patient dose escalation (IPDE) of ripretinib after disease progression in patients with advanced gastrointestinal stromal tumor (GIST): Analyses from the phase 3 INVICTUS study

11536

Background: Ripretinib is a switch-control tyrosine kinase inhibitor that broadly inhibits KIT and PDGFRA kinase signaling. In the INVICTUS study (NCT03353753), patients with advanced GIST (≥4th-line) receiving ripretinib had a median progression-free survival (mPFS) of 6.3 months vs 1.0 month for patients receiving placebo (HR = 0.15, p <0.0001). In an earlier phase 1 dose escalation study, the maximum tolerated dose was not reached with doses up to 200 mg twice daily (BID). Here, we report efficacy, safety, and pharmacokinetic data for IPDE patients initially randomized to ripretinib from the phase 3 INVICTUS study based on data as of 10 Aug 2020. Methods: A total of 129 patients were randomized 2:1 to ripretinib 150 mg once daily (QD; n = 85) or placebo (n = 44). Patients receiving ripretinib 150 mg QD who had progressive disease (PD) as assessed by blinded independent central review (BICR) using mRECIST were given the option for IPDE to 150 mg BID. Tumor response assessments were performed every 28 days for 4 cycles and every 56 days thereafter (including after IPDE). The primary endpoint was PFS. For this exploratory analysis, PFS1 for IPDE patients was defined as the time from randomization to PD; PFS2 for IPDE patients was the time from the first dose of ripretinib 150 mg BID to PD or death. PFS1 and PFS2 were based on BICR. Results: Of 85 patients treated with ripretinib 150 mg QD, 43 patients with BICR PD dose escalated to 150 mg BID. Baseline characteristics of IPDE patients at time of study entry were similar to those observed in the original ripretinib QD arm and similar to the 22 patients with BICR PD who either remained on 150 mg QD or discontinued treatment. IPDE patients had a mPFS1 of 4.6 months (95% CI, 2.7–6.4) and a mPFS2 of 3.7 months (95% CI, 3.1–5.3); mPFS2/mPFS1=80%. The IPDE dosing period was well tolerated without the emergence of new safety concerns. The most common new or worsening (unchanged or improving grades not included) treatment-emergent adverse event (TEAE) for IPDE patients during the BID period was abdominal pain (30.2% all grades and 7% Grade 3–4 vs 41.9% and 4.7% in QD period, respectively). The most common Grade 3–4 TEAE in the BID period was anemia (14% vs 2.3% in QD period). IPDE from QD to BID resulted in an approximately 2-fold increase in the steady state trough concentration. Conclusions: Similar to the phase 1 study wherein IPDE to 150 mg BID following PD provided clinical benefit with a mPFS1 of 5.5 months and mPFS2 of 4.6 months (mPFS2/mPFS1=84%) for patients with ≥4th-line GIST, these analyses from INVICTUS indicate that IPDE to ripretinib 150 mg BID can also provide additional meaningful clinical benefit and a similar tolerability profile to the 150 mg QD regimen for patients with ≥4th-line GIST that progressed following treatment with ripretinib 150 mg QD. Clinical trial information: NCT03353753.

Evaluating longitudinal toxicity of cetuximab in patients with metastatic colorectal cancer (mCRC): A pooled analysis from 1,302 patients in the ARCAD database

3610

Background: Chronic lower grade adverse events (AE) can negatively affect a patient’s quality of life but it is difficult to capture using a traditional toxicity reporting approach. A novel AE reporting method was recently developed to describe, summarize, and present longitudinal AE profiles(Lopes et al, 2021). We leveraged this method to describe and compare the AE profiles of doublet chemotherapy (DC) + Cetuximab and DC alone in mCRC patients. Methods: This AE reporting method utilizes two additional AE metrics to complement the maximum (max) toxicity grade usually reported in clinical trials. Onset time indicates the time period in which max grade for an AE occurred for the first time, defined here as “early” (i.e. within first 42 days) and “late” (i.e. after the 42nd day). AE Load (AEL) indicates the overall severity of an AE in the entire treatment. AEL varies from 0 to 1. Higher AEL indicates a worse overall severity of that AE over time. AEL is the key metric for describing chronic AE. We included patients receiving DC + cetuximab (n = 738) and DC alone (n = 564 [ref group]) from two randomized first-line trials in the ARCAD database. Diarrhea, rash, hand-foot syndrome (HFS), fatigue, anorexia, and mucositis were examined and adjusted for backbone (FOLFOX vs. FOLFIRI), ECOG PS, sex, site location, dose reduction, and treatment length. Results: For rash, DC + cetuximab had a higher risk of G3+ (21% vs. 0.5%; odds ratio {OR} [95% confidence interval {CI}] = 50 [16,157], p < 0.001), increased overall severity over the entire treatment (AEL = 0.257 vs. 0.069; Adjusted difference in means–Mdiff [95% CI] = 0.22 [0.21,0.23], p < 0.001), and increased risk of early onset (67% vs. 33%; OR [95% CI] = 4.3 [2.7,6.7], p < 0.001). DC + cetuximab also had higher AEL for rash across max grades (p < 0.001 within G1, G2, and G3+). For HFS, DC + cetuximab had a higher risk of G3+ (OR [95% CI] = 6.0 [2.5,14], p < 0.001), increased overall severity (AEL = 0.139 vs. 0.087; Mdiff [95% CI] = 0.03 [0.03,0.04], p < 0.001), and slightly earlier onset (12.4 vs. 13.9 weeks; Mdiff, weeks [95% CI] = -4.9 [-0.80,-9.0], p = 0.021). Within each max grade, DC + cetuximab did not have higher AEL of HFS. No associations were found for diarrhea, fatigue, anorexia, or mucositis. Conclusions: The addition of cetuximab is associated with higher grade, more persistent, and more immediate rash. The higher severity in HFS with the addition of cetuximab appears to be related to higher grade but not chronic HFS. This method may be useful to describe different strategies, e.g. intermittent cetuximab. It provided a comprehensive view of acute and chronic toxicity profiles supporting its potential interest as new metrics in clinical trials. Lopes GS, Tournigand C, Olswold CL, et al. Adverse event load, onset, and maximum grade: A novel method of reporting adverse events in cancer clinical trials. Clinical Trials. 2021;18(1):51-60

Phase III study of NUC-1031 + cisplatin vs gemcitabine + cisplatin for first-line treatment of patients with advanced biliary tract cancer (NuTide:121)

TPS351

Background: Biliary tract cancer (BTC) carries a poor prognosis and no first-line treatments are approved. The accepted global standard of care is gemcitabine + cisplatin (GemCis). NUC-1031 is a phosphoramidate transformation of gemcitabine designed to overcome key cancer resistance mechanisms that are associated with gemcitabine. Promising efficacy has been observed with single-agent NUC-1031 in a phase I study in advanced solid tumors and in the phase Ib ABC-08 study of NUC-1031 + cisplatin for first-line treatment of advanced BTC. Of 14 patients enrolled in 2 cohorts (NUC-1031 625 mg/m2 or 725 mg/m2 + cisplatin 25 mg/m2 on Days 1 and 8 of 21-day cycle), 1 had a CR and 6 had PRs, resulting in an unconfirmed ORR of 50%. This represents an approximate doubling of ORR over SoC. The combination was well-tolerated with no unexpected AEs or DLTs. The RP2D of NUC-1031 with cisplatin was 725 mg/m2. The tolerability profile, together with encouraging efficacy, suggested NUC-1031 + cisplatin may represent a more effective therapy than GemCis for BTC and led to initiation of a global registrational study. Methods: NuTide:121 is a Phase III, open-label, randomized study of NUC-1031 + cisplatin vs GemCis for first-line treatment of advanced BTC. Patients ≥18 years with histologically- or cytologically-confirmed BTC (including cholangiocarcinoma, gallbladder, or ampullary cancer), who have had no prior systemic chemotherapy for locally advanced/metastatic disease, are eligible. A total of 828 patients are being randomized (1:1) to either 725 mg/m2 NUC-1031 or 1000 mg/m2 gemcitabine, both with 25 mg/m2 cisplatin, administered on days 1 and 8 of 21-day cycles. Primary objectives are OS and ORR. Secondary objectives include PFS, safety, PK and patient-reported quality of life. In addition to the final analysis, three interim analyses, including two designed to support accelerated approval, are planned. The study has passed an initial safety analysis, with no protocol changes required. NuTide:121 is being conducted at approximately 130 sites across North America, Europe and Asia Pacific countries. Clinical trial information: NCT04163900.

Tumor bulk as a prognostic biomarker and predictor of benefit from anti-EGFR therapy in patients with metastatic colorectal cancer: Analysis of 476 patients from the ARCAD Clinical Trials Program

108

Background: Primary tumor sidedness has emerged as a prognostic and predictive biomarker for patients (pts) with metastatic colorectal cancer (mCRC). Tumor bulk has also been postulated to predict response to anti-EGFR therapy. We sought to evaluate the role of tumor bulk as a predictive biomarker to anti-EGFR therapy in pts with left- (LS) and right-sided (RS) mCRC. Methods: Data from 476 pts with mCRC enrolled across 2 first-line trials of anti-EGFR plus chemotherapy versus chemotherapy were pooled. Pts were included if there was available information on tumor sidedness and tumor bulk. All were KRAS wild-type and BRAF wild-type or unknown BRAF status. The right colon was defined as the cecum through the transverse colon, and the left colon as the splenic flexure through the rectum. Tumor bulk was the mean tumor size of target lesions at baseline, bulky defined as > 3.5 cm. Overall survival (OS) and progression-free survival (PFS) were assessed using Kaplan-Meier and Cox models adjusting for performance status (PS), platelet count, primary tumor (PT) resection, number of metastatic sites, and stratified by study. Results: Pts with bulky tumors (211, 44%) had higher PS, white blood cell and platelet counts, higher CEA, fewer sites of metastatic disease, more liver than lung metastases, and fewer had PT resection. OS and PFS medians in months (mos) are presented in the table with 95% confidence intervals (95%CIs). Bulky tumors had inferior median OS compared with non-bulky (mOS, 17.9 vs. 21.3 mos, HRadj 1.33, 95% CI 1.05-1.69, P = 0.016) although median PFS was similar (mPFS, 8.6 vs. 8.7 mos, HRadj 1.15, 95% CI 0.92-1.42, P = 0.21). Conclusions: Tumor bulk is an independent prognostic factor for OS in KRAS wild-type and BRAF wild-type or unknown BRAF status pts. Pts with non-bulky RS tumors have survival outcomes similar to pts with bulky LS tumors. Although the mPFS for pts with RS tumors treated with anti-EGFR therapy was the lowest across subgroups, this finding was not statistically significant. Further research is warranted into whether pts with bulky RS tumors benefit from anti-EGFR therapy. Clinical trial information: NCT00182715, NCT00640081. [Table: see text]

NUC-1031/cisplatin versus gemcitabine/cisplatin in untreated locally advanced/metastatic biliary tract cancer (NuTide:121)

Gemcitabine/cisplatin is standard of care for first-line treatment of patients with advanced biliary tract cancer (aBTC); new treatments are needed. NUC-1031 is designed to overcome key cancer resistance mechanisms associated with gemcitabine. The tolerability/efficacy signal of NUC-1031/cisplatin in the Phase Ib ABC-08 study suggested that this combination may represent a more efficacious therapy than gemcitabine/cisplatin for patients with aBTC, leading to initiation of the global NuTide:121 study which will include 828 patients ≥18 years with untreated histologically/cytologically-confirmed aBTC (including cholangiocarcinoma, gallbladder or ampullary cancer); randomized (1:1) to NUC-1031 (725 mg/m2)/cisplatin (25 mg/m2) or gemcitabine (1000 mg/m2)/cisplatin (25 mg/m2), on days 1/8, Q21-days. Primary objectives are overall survival and objective response rate. Secondary objectives: progression-free survival, safety, pharmacokinetics, patient-reported quality of life and correlative studies. (Investigational new drug (IND) number: 139058, European Clinical Trials database: EudraCT Number 2019-001025-28, ClinicalTrials.gov identifier: NCT04163900).

Australasian Gastrointestinal Trials Group (AGITG) CONTROL NET Study: Phase II study evaluating the activity of 177Lu-Octreotate peptide receptor radionuclide therapy (LuTate PRRT) and capecitabine, temozolomide CAPTEM)—First results for pancreas and updated midgut neuroendocrine tumors (pNETS, mNETS)

4608

Background: CAPTEM is an accepted regimen for patients (pts) with advanced pNETs. Single agent 177Lu-Octreotate PRRT is now a standard of care for progressive WHO Grade (G) 1/2 mNETs. High activity was seen with LuTate/CAPTEM in a single arm Phase I/II trial. This study was undertaken to determine the relative activity of adding CAPTEM to LuTate PRRT in pts with mNETs and pNETs. Methods: Non-comparative randomised open label parallel group phase II trial with 2:1 randomisation to PRRT/CAPTEM (experimental arm) vs. PRRT (mNETs control) and CAPTEM (pNETS control). PRRT/CAPTEM: 7.8GBq LuTate day(D) 10, 8 weekly (wkly) x 4, with b.i.d. oral CAP 750mg/m2 D1-14 & TEM 75mg/m2D10-14, 8 wkly x 4; PRRT: 8 wkly x 4; CAPTEM 8 wkly x 4. Primary endpoint: Progression free survival (PFS). mNETS- at 15 months (mo) assuming 15mo PFS 66.4% in control arm, aiming for PFS ³ 80%; pNETS- at 12mo assuming 12mo PFS 60% in control arm, aiming for PFS ³ 75%. Secondary endpoints: Objective tumour response rate (complete or partial) (OTRR), clinical benefit rate (OTRR, stable disease) (CBR), toxicity, quality of life. Results: 75 pts enrolled (Dec 2015 – Nov 2018): mNETs 33 PRRT/CAPTEM and 14 PRRT; pNETS 19 PRRT/CAPTEM and 9 CAPTEM. mNETS: Median follow-up 35mo; 15mo PFS was 90% (95% CI: 73-97%) v 92% (95% CI: 57-99%); OTRR 31% vs 15%; and CBR 97% vs 92% for PRRT/CAPTEM v PRRT respectively. Treatment related adverse events (AEs): 24/32 PRRT/CAPTEM pts had at least one G3 event (75%) vs 5/13 (38%, PRRT); and 4/32 pts at least one G4 event (13%) v 1/13 (8%) respectively, mostly haematologic (haem). Only one patient failed to complete therapy (PRRT/CAPTEM). pNETS: Median follow-up 34mo; 12mo PFS was 76% (95% CI: 48-90%) v 67% (95% CI: 28-88%); OTRR 68% vs 33%; and CBR 100% vs 100% for PRRT/CAPTEM v CAPTEM respectively. Treatment related AEs: 5/18 PRRT/CAPTEM pts had at least one G3 event (28%) vs 3/9 (33%) CAPTEM; 3/18 pts at least one G4 event (17%) v 1/9 (11%) respectively. Conclusions: CAPTEM/PRRT is active, meeting its target landmark PFS for CAPTEM/PRRT (12mo pNETs; 15mo mNETs) with numerically greater OTRR in both pNETs and mNETs, but with more haem toxicity in mNETs. As activity was high in both control arms longer follow up is required to determine if the relative activity of PRRT/CAPTEM is sufficient to warrant Phase III evaluation. Clinical trial information: ACTRN12615000909527 .

Quality of life (QoL) and self-reported function with ripretinib in ≥4th-line therapy for patients with gastrointestinal stromal tumors (GIST): Analyses from INVICTUS

11535

Background: Ripretinib is a novel switch-control tyrosine kinase inhibitor (TKI) that broadly inhibits KIT and PDGFRA kinase signaling through a dual mechanism of action. In INVICTUS (NCT03353753), a randomized, double-blind, placebo-controlled trial of ripretinib in ≥4th-line advanced GIST, ripretinib reduced the risk of disease progression or death by 85% vs placebo and had a favorable overall safety profile in patients previously treated with ≥3 prior TKIs. Methods: As part of the INVICTUS trial, patient reported outcome (PRO) measures were collected using EQ-5D-5L (EQ5D) and EORTC QLQ-C30 (C30). In prespecified and additional analyses, ANCOVA models were built to compare changes from baseline to cycle 2 day 1 (C2D1) for PRO measures within the ripretinib and placebo arms and determine the difference between treatment arms. PRO measures included the EQ5D visual analogue scale (VAS) and the C30 physical functioning (PF) and role functioning (RF) scales (all scores range from 0–100; higher scores are better). The C30 overall health and overall QoL questions were also assessed (scores range from 1–7; higher scores are better). Fixed effects included treatment arm, number of previous anticancer treatments (3 vs ≥4), and ECOG score at baseline (0 vs 1/2). Results: Overall, 129 patients were randomized and 128 received treatment (85 to ripretinib 150 mg QD; 43 to placebo). All PRO p-values are nominal, and no statistical significance is being claimed. VAS scores improved an average 3.7 points from baseline to C2D1 with ripretinib vs an average decline of 8.9 with placebo (P = 0.004; improvement or no change, 67% vs 41% of patients, respectively). Similarly, the average PF score improved 1.6 points with ripretinib and decreased 8.9 with placebo (P = 0.004; improvement or no change, 68% vs 44%). RF scores also improved an average of 3.5 points with ripretinib vs a decrease of 17.1 with placebo (P = 0.001; improvement or no change, 77% vs 50%). For the overall health and overall QoL questions, scores increased with ripretinib an average of 0.20 and 0.28, respectively, and decreased 0.78 and 0.76 with placebo (both P = 0.001; improvement or no change, 74% vs 47% and 79% vs 59%, respectively). Conclusions: Based on the 5 PRO measures assessed, when compared with placebo and best supportive care, ripretinib provided patient-benefit in advanced GIST with PRO measures of role and physical function, VAS, overall health, and overall QoL remaining stable. Clinical trial information: NCT03353753 .

Safety profile of ripretinib, including impact of alopecia, and Palmar-Plantar Erythrodysesthesia Syndrome (PPES) on patient-reported outcomes (PROs), in ≥ fourth-line advanced gastrointestinal stromal tumors (GIST): Analyses from INVICTUS

11539

Background: Ripretinib is a novel switch-control TKI that broadly inhibits KIT and PDGFRA kinase signaling. In INVICTUS (NCT03353753), a randomized, double-blind, placebo (PBO)-controlled trial of ripretinib in ≥4th-line advanced GIST, ripretinib reduced the risk of disease progression or death by 85% vs PBO with a favorable overall safety profile. Common ( > 20%) adverse events (AEs) included, but were not limited to, alopecia and PPES. Exploratory analyses evaluated the impact of alopecia and PPES on quality of life (QoL). Methods: Patients (pts) with advanced GIST previously treated with at least imatinib, sunitinib, and regorafenib were randomized (2:1) to ripretinib 150 mg QD or PBO. AEs were graded using CTCAE v4 and PROs collected using EQ-5D-5L (EQ5D) and EORTC QLQ-C30 (C30). Repeated measures (RM) models assessed the impact of alopecia and PPES on 5 PROs (EQ5D visual analogue scale; and C30 physical functioning, role functioning, and the overall health and overall QoL questions) within the ripretinib arm. Fixed effects were sex, alopecia/PPES, and ECOG scores at baseline. Results: 128/129 randomized pts received treatment (85 ripretinib 150 mg QD; 43 PBO). Alopecia, regardless of causality, occurred in 44 (51.8%) on ripretinib (34 [40.0%] grade 1; 10 [11.8%] grade 2) and 2 (4.7%) on PBO (both grade 1). PPES occurred in 18 (21.2%) on ripretinib (11 [12.9%] grade 1; 7 [8.2%] grade 2); none on PBO. The median times in days to first occurrence and worst severity grade with ripretinib were 57.0 and 62.5 for alopecia; 56.5 and 57.0 for PPES. The RM models showed a slight trend towards improvement in PRO score over time for pts with alopecia; the only association reaching a P-value of < 0.05 was between alopecia and increased overall QoL. None of the associations between PPES and PRO scores reach P < 0.05. All PRO p-values are nominal, and no statistical significance is being claimed. Conclusions: Ripretinib had a favorable overall safety and tolerability profile. When stratified by alopecia and PPES, patient-reported assessments of function, overall health, and overall QoL were maintained over time. For both alopecia and PPES, onset and maximum severity occurred almost simultaneously, indicating that these events generally did not progressively worsen. These results suggest that alopecia and PPES are manageable and do not have a negative effect on function, overall health, and QoL. Clinical trial information: NCT03353753 .

Treatment effects (TEs) of EGFR monoclonal antibodies (mAbs) in metastatic colorectal cancer (mCRC) patients (pts) with KRAS, NRAS, and BRAF mutation (MT) status: Individual patient data (IPD) meta-analysis of randomized trials from the ARCAD database

4090

Background: EGFR mAbs have become incorporated into clinical practice for the management of mCRC over the last decade. KRAS and NRAS mutations are used as predictive biomarkers and BRAF V600E mutations are associated with an adverse prognosis. The observed TE within biomarker subpopulations has varied between studies. Methods: IPD from randomized trials with head-to-head comparison between EGFR mAb versus no EGFR mAb (chemotherapy alone or BSC) in mCRC, across all lines of therapy (first, second and later), were pooled. Biomarker subpopulations are defined in the table. Overall survival (OS) and progression-free survival (PFS) were compared between groups by Cox model, stratified by studies and adjusted by age, gender, and performance status. TEs were estimated by adjusted hazard ratio (HRadj) and 95% confidence interval (CI). Within each biomarker subgroup, EGFR mAb efficacy was explored according to multiple exploratory factors, including line of therapy, type of backbone chemo, gender, sidedness and site of metastasis. Interaction tests were performed. P-values < 0.01 were considered statistically significant to account for multiple comparisons. Results: 5729 pts from 8 studies with data available for ≥ 1 biomarker were analysed. PFS benefits (median 9.2 mos in EGFR mAbs, 8.0 mos in no EGFR mAbs) were confirmed in triple-WT pts, but not for OS (refer to table). No OS/PFS benefits were observed for pts with any of the MT tumors. Exploratory analyses showed a potential detrimental TE of EGFR mAbs in KRAS MT mCRC with liver metastasis (OS: HRadj 1.22, p = .003, pinteraction .0056; PFS: HRadj 1.24, p = .0009, pinteraction .0008). These results were confirmed within the subgroup of pts with all 3 biomarkers available. Conclusions: This is the largest IPD analysis to explore the predictive value of RAS/BRAF biomarkers in mCRC. Our findings demonstrate that there is no evidence of efficacy of EGFR mAbs in KRAS, BRAF and/or NRAS MT mCRC. EGFR mAbs might have a detrimental effect in KRAS MT mCRC with liver metastases. [Table: see text]

Sex differences in efficacy and toxicity of first-line treatment of metastatic colorectal cancer (CRC): An analysis of 18,399 patients in the ARCAD database

4029

Background: The clearance of 5-FU differs significantly between men (M) and women (W). Adjuvant chemotherapy (CT) for CRC has a higher toxicity in W. The impact of sex on efficacy and toxicity in first-line trials of metastatic CRC (mCRC) is unknown. Methods: We analyzed patient (pt) and tumor characteristics, toxicities (nausea (AE1), vomiting (AE2), diarrhea, neutropenia (AE3)) and efficacy (overall survival (OS), progression-free survival (PFS)) according to sex in the following treatment groups: A: CT alone, B: CT + bevacizumab, C: CT + EGFR-antibodies, with subgroup analyses in the CT alone group for single-agent, doublets and triplets, as well as irinotecan- and oxaliplatin-based regimens. Pts from trials with treatments still used today and all relevant data available were eligible. OS and PFS were assessed using Kaplan-Meier and Cox models adjusted for primary tumor location and performance status (PS). Results: We included 28 trials with 18.399 pts (11.352 M and 7.047 W). W were younger (61 vs. 63 years), had more often a PS of 1 (49 vs 45%), BRAF mutations (10 vs. 7%), right-sided tumors (42 vs. 35%) and less often rectal tumors (26 vs. 32%). Significant differences in toxicity are reported in table. Rates of diarrhea were similar. There was no sex disparity in OS in the predefined subgroups except for pts receiving triplets where OS was better in M (HRadj=1.39 (1.05 - 1.85)). Median (interquartile range) OS in months for M and W was 16.7 (9.2-27.4) and 16.2 (8.9-27.2) in group 1, 21.9 (12.7-37.5) and 22.3 (12.9 – 39.0) in group 2, and 26.8 (14.6-45.3) and 24.8 (12.3-49.2) in group 3. HRsadj (W vs M) (95% CI), p values for OS were 1.02 (0.96-1.09), .557, 0.92 (0.83-1.03), .142, 0.99 (0.85-1.14), .866. Conclusions: M and W with mCRC differ significantly regarding patient and tumor characteristics. The significant higher toxicity in W does not translate in a higher treatment efficacy. Apart from known sex differences in pharmacokinetics of 5-FU, differences in pharmacodynamics must be postulated. [Table: see text]

First results for Australasian Gastrointestinal Trials Group (AGITG) control net study: Phase II study of 177Lu-octreotate peptide receptor radionuclide therapy (LuTate PRRT) +/- capecitabine, temozolomide (CAPTEM) for midgut neuroendocrine tumors (mNETs)

604

Background: Single agent 177Lu-octreotate peptide receptor radionuclide therapy is now a standard of care for progressive mNETS. High activity was seen with LuTate and concurrent CAPTEM chemotherapy in a single arm Phase I/II trial. This study was undertaken to determine the relative activity of adding CAPTEM to LuTate PRRT in patients with mNETs. Methods: Non-comparative randomised open label phase II trial of PRRT +/- CAPTEM in patients with mNETs, with 2:1 randomisation: PRRT /CAPTEM (experimental arm) vs. PRRT (control). PRRT /CAPTEM: 7.8GBq LuTate day(D) 10, 8 weekly (wkly) x 4, with b.i.d. oral CAP 750mg/m2 D1-14 & TEM 75mg/m2 D10-14, 8 wkly x 4, vs. PRRT 8 wkly x 4. Primary endpoint: progression free survival (PFS) at 15 months assuming 15 month PFS of 66.4% in the control arm, aiming for PFS rate > 80%; secondary endpoints: objective tumour response rate (complete or partial response) (OTRR), clinical benefit rate (complete or partial response, stable disease) (CBR), toxicity, and QOL. Results: 47 patients enrolled (Dec 2015 - Feb 2018): 33 PRRT/CAPTEM and 14 PRRT. Two patients withdrew prior to treatment. Patient characteristics were balanced except gender (female 58% vs. 14%). Two patients received 2 prior systemic regimens. After a median follow-up of 32 months, the 15 month PFS was 90% (95% CI: 73-97%) v 92% (95% CI: 57-99%); OTRR 25% vs 15%; and CBR 97% vs 92% for PRRT/CAPTEM v PRRT respectively. For treatment related adverse events 22/32 CAPTEM patients experienced one Grade 3 event (69%) vs 5/13 (38%, PRRT); 4/32 pts experienced one Grade 4 event (13%) v 1/13 (8%) respectively. Only one patient failed to complete therapy due to toxicity (PRRT/CAPTEM). Conclusions: This initial planned analysis demonstrates similarly high 15 month PFS for CAPTEM/PRRT relative to PRRT alone. OTRR is numerically higher but at the cost of greater toxicity. Longer follow up is required to determine if the activity of PRRT/CAPTEM is sufficient to warrant Phase III evaluation. Clinical trial information: ACTRN12615000909527.

How to improve toxicity evaluation in clinical trials? Testing new metrics from irinotecan or oxaliplatin-based treatments in metastatic colorectal cancer (mCRC): A pooled analysis from 2,349 patients in ARCAD database

89

Background: Monitoring of adverse events (AE) is crucial in clinical trials. Maximum grade per patient (pt) is commonly used but better metrics are needed to aid describing and comparing AE profiles. Methods: We developed and evaluated 2 longitudinal AE summary metrics. 1) Onset time of max grade refers to whether a pt has max grade within pre-specified timeframes for an AE, e.g. onset can be defined as “early” (max grade before the 6th cy) or “late” (≥ 6th cy). 2) Adverse effect load (AEL) is a longitudinal score of worst grade possible excluding death over the entire treatment for an AE. Higher AEL means worst overall experience of AE. We applied these metrics to real trial data. Pts were from 6 mCRC trials included in ARCAD database and received Irinotecan-based (n = 1,119) or Oxaliplatin-based (n = 1,230) treatments that did not include biologicals. AEs were diarrhea, nausea/vomiting, neutropenia/leukopenia, and neuropathy. We used linear model to AEL and logistic model to the other metrics, adjusting for age, sex, and number of metastases. Results: For nausea/vomiting, pts in Oxali-based chemo showed a higher AEL compared to patients in Iri-based (mean (M) [standard deviation (SD)] = 0.04 [0.06] vs. 0.02 [0.04]; p < 0.001) even though less pts had gr ≥ 3 (10.4% vs. 16.2%, resp.; p < 0.001), suggesting a lower-grade but persistent nausea/vomiting for Oxali-based. Among pts with diarrhea max gr 2, pts in Iri-based had higher AEL than with Oxali-based (M [SD] = 0.11 [0.11] vs. 0.08 [0.09]; p = 0.008), indicating more persistent diarrhea for Iri-based trts even among pts with same max grade. For neutropenia/leukopenia, pts in Oxali-based trts experienced higher AEL (M [SD] = 0.09 [0.13] vs. 0.05 [0.11], p < 0.001), and more pts in Oxali-based trts had gr ≥ 3 (70.1% vs. 64.4%; p = 0.002), suggesting that pts in Oxali-based trts experienced worst overall and max grade neutropenia/leukopenia compared to pts in Iri-based. Conclusions: To improve toxicity assessment in clinical trials, AEL and onset time of max grade are new measures that describe the evolution of adverse events over time. Further validation is warranted.

NUC-1031 in combination with cisplatin for first-line treatment of patients with advanced biliary tract cancer (NuTide:121)

TPS602

Background: Biliary tract cancer (BTC) carries a poor prognosis and has no approved treatments. Although gemcitabine + cisplatin (GemCis) is accepted as the global standard of care (SoC) for 1st-line treatment, the reported unconfirmed ORR and OS from randomized studies of this combination are low at 18.5-26.1% and 11.2-11.7 months, respectively. NUC-1031, a phosphoramidate transformation of gemcitabine, is designed to overcome key cancer resistance mechanisms associated with gemcitabine. Promising signs of efficacy have been observed with single-agent NUC-1031 in a Phase I study in advanced solid tumors (Blagden et al 2018) and in the Phase Ib ABC-08 study of NUC-1031 + cisplatin 25 mg/m2 on days 1 and 8 of a 21-day cycle for the 1st-line treatment of advanced BTC. Of 14 patients (pts) enrolled in 2 cohorts (NUC-1031: 625 mg/m2 and 725 mg/m2), 1 pt achieved a CR and 6 pts achieved PR, giving an unconfirmed ORR of 50% and representing an approximate doubling of ORR over SoC. The combination was well-tolerated with no unexpected adverse events or dose-limiting toxicities. The RP2D of NUC-1031 in combination with cisplatin is 725 mg/m2. The tolerability profile together with robust efficacy signals suggested NUC-1031 + cisplatin may represent a more effective therapy than GemCis for BTC and led to initiation of a global Phase III study. Methods: A Phase III, open-label, randomized head-to-head study of NUC-1031 + cisplatin versus GemCis for 1st-line treatment of advanced BTC will include pts ≥18 years with histologically- or cytologically-proven BTC (including cholangiocarcinoma, gallbladder, or ampullary cancer), who have had no prior systemic chemotherapy for locally advanced/metastatic disease. A total of 828 pts will be randomized (1:1) to either 725 mg/m2 NUC-1031 + 25 mg/m2 cisplatin or 1000 mg/m2 gemcitabine + 25 mg/m2 cisplatin, administered on days 1 and 8 of a 21-day cycle. Primary objectives are OS and ORR. Secondary objectives include further measurements of efficacy, safety, pharmacokinetics, and patient-reported quality of life. The study will be conducted at approximately 120 sites across North America, Europe and Asia Pacific countries. Clinical trial information: NCT04163900.

ALT-GIST: Randomized phase II trial of imatinib alternating with regorafenib versus imatinib alone for the first-line treatment of metastatic gastrointestinal stromal tumor (GIST)

11023

Background: Imatinib (IM) is the standard first-line treatment for advanced GIST and regorafenib (REG) is approved for third line therapy. We studied if an alternating regimen of two tyrosine kinase inhibitors, IM and REG, delays resistance to IM and improves outcomes. Methods: ALT-GIST (NCT02365441) is a randomised non-comparative phase II trial to investigate the efficacy of an alternating regimen (ALT) of 21-25 days of IM 400mg orally daily followed by a 3-7-day gap for washout followed by 21 days of REG 160 mg orally daily and a 7-day gap for washout. The control arm was continuous IM 400mg daily. Delayed recruitment led to revised endpoints of activity and safety. To assess clinical activity, the best objective tumor response (OTR) at 9 months was deemed to be an appropriate endpoint in the revised protocol. Results: Seventy-six eligible patients (ALT 40, IM 36) enrolled from June 2015 to September 2018 were evaluable for the OTR. The patients (pts) were predominately male (n = 51, 67%). Median age was 58 (range, 24-81) in the ALT arm and 65 (range, 35-82) in the IM arm. KIT was mutated in 63, PDGFR in 2, and wildtype in 5 tumors. Relative dose intensity in the ALT arm 102% for IM and 82% for REG and was 93% in the IM arm. Median follow-up time was 19.3 months (range 6.0-40.0).The best responses to the ALT and IM treatments were similar at 9 months, 1 vs 0 pts had complete response, 23 vs 23 partial response, 15 vs 13 stable disease, and the OTR was 60% (95% CI, 45-74%) and 64% (95% CI, 48-78%), respectively. Seven (18%) pts in ALT arm and 10 (28%) in IM arm discontinued treatment due to progressive disease. Seven pts (18%) in the ALT arm stopped protocol therapy due to unacceptable toxicity, and none in the IM arm. Fifteen (38%) pts in the ALT arm and 14 (38%) in the IM arm had serious adverse events, mostly grade 3. Progression free survival (PFS) at 1 year was ALT 0.86 (95%CI:0.69,0.94) and IMI 0.83 (95% CI 0.65-0.92), p logrank = 0.57. Conclusions: There was no meaningful difference in the primary endpoint of OTR and in PFS between the groups in this first analysis of ALT-GIST, and no unexpected safety signals. The study is ongoing and other endpoints will be reported in due course. Clinical trial information: ACTRN12614000950662.

Phase II trial PD-L1/PD-1 blockade avelumab with chemoradiotherapy for locally advanced resectable T3B-4/N1-2 rectal cancer: The Ave-Rec trial

TPS3622

Background: Standard neoadjuvant long course chemoradiotherapy (LCCRT) for locally advanced rectal cancer (LARC) results in a complete pathological response rate of 10-30%: but 20-40% of patients (pts) are non-responders, 10-15% have local recurrence. Tumoural immune infiltrates are predictive of response. Preclinical studies show that radiotherapy (RT) via interferon signaling is immuno-stimulatory, enhancing local/distant tumour cell death. RT also stimulates PDL1 production and the immunosuppressive activity of myeloid derived suppressor cells. Hence PDL1 inhibition may be required to enhance the immuno-stimulatory effects of RT. Hypothesis: In pts with resectable LARC, the anti-PDL1 antibody Avelumab post LCCRT may enhance the pathological/imaging response rates whilst potentially reducing local/distant relapse rates. Methods: (1) Trial Design: Phase II single arm trial, across 6 Australian sites (2) Endpoints: (a) Primary; Pathological response rate post-LCCRT, as documented by central pathologist, (b) Secondary; MRI/FDG PET imaging responses at 8 weeks post LCCRT (pre-surgery). Toxicity. (c) Exploratory; Tumoural immune cell subsets/checkpoint expression (by multiplex immunohistochemistry and in-vitro functional assays) and ctDNA analysis at baseline and during treatment. Distant relapse-free survival and the documentation of sites of relapse. (3) Sample size: An increase in the proportion of pathological complete responses by > 25% (from 10% to 35%) will be considered clinically important. Power = 90%, α = 0.05, 41 pts are required– an additional 4 pts to allow for drop-out. Total sample size = 45pts. Treatment: All pts to receive standard LCCRT (50.4Gy RT plus 5FU [225mg/m2/day/CI] or Capecitabine [825mg/m2 BID on RT days] over 5.5 weeks). Post LCCRT (prior to surgery), pts receive 4 cycles Avelumab (10mg/kg, q2 weeks). Surgical resection 10-12 weeks post LCCRT. Fresh tumour biopsy and ctDNA sampling pre LCCRT, pre Cycle 1 Avelumab and at surgery. Response by FDG PET and pelvic MRI pre surgery. Pts to be followed up for 2 years. Major Inclusion Criteria: Pts with LARC, MRI stage T3b-4/N1-2/M0, planned for LCCRT followed by curative resection, tumoural lower border within 12cm from the anal verge, measurable disease (RECIST1.1), ECOG 0-1, adequate organ function and no contraindications to Avelumab therapy. Current Enrolment: 11 of the planned 45 patients enrolled. Clinical trial information: NCT03299660.

Expanded RAS and BRAF V600 testing as predictive biomarkers for single agent cetuximab in the randomized phase III CO.17 trial

537

Background: KRAS/NRAS ( RAS) testing of exons 2, 3 and 4 is standard prior to anti-EGFR treatment in metastatic colorectal cancer and many consider BRAFV600 ( BRAF) mutations predictive. CO.17 was a randomized phase III trial comparing cetuximab vs best supportive care (BSC) in unselected patients (pts). Re-analysis tested only KRAS exon 2, thus the benefit of cetuximab in RAS/BRAF wild type (WT) pts is unclear. Methods: We retrospectively performed expanded RAS/BRAF testing using a highly sensitive digital PCR method (BEAMing; 1% allele frequency detection limit) on micro-dissected archival tissue from 248 CO.17 pts. Additional pts without available archival tissue, with prior Sanger sequencing or therascreen results were included in analyses if mutations were previously detected (n = 77). Overall survival (OS), progression free survival (PFS), and response rates (RR) were compared by molecular profile. Results: Of 248 sequenced pts, 139 (56%) were RAS mutant, with 112 (45%) exon 2, 11 (4%) exon 3 and 6 (2%) exon 4 KRAS mutant, and 10 (4%) NRAS mutant pts. Seven (3%) BRAF mutant, and 97 (30%) confirmed RAS/BRAF WT pts were identified. Results are summarized below. A test of interaction indicated RAS status was predictive for PFS (p = 0.0001) and OS (p = 0.037) and BRAF status neared significance as a predictive marker for PFS (p = 0.089) but not OS (p = 0.24). Conclusions: These updated results demonstrate an improved PFS (HR 0.25 vs 0.40 previously) and OS (HR 0.51 vs 0.55 previously) for cetuximab in RAS/BRAF WT pts compared to prior analyses that included only KRAS exon 2 mutation status. We provide an estimate of single agent cetuximab efficacy for future anti-EGFR re-challenge studies and demonstrate further support that BRAF mutations may predict lack of benefit from anti-EGFR therapy. Clinical trial information: NCT00079066. [Table: see text]

Real-world treatment patterns and clinical outcomes in patients receiving second-line (2L) treatment for advanced or metastatic gastric cancer (GC)

102

Background: Despite increased survival demonstrated for patients with advanced / metastatic GC due to 2L chemotherapy, different standard of care options exist. This study aims to describe RW treatment patterns and clinical outcomes in patients with advanced / metastatic GC receiving 2L treatment. Methods: Retrospective chart review study conducted in Australia, Canada, Italy and UK. Patients diagnosed with metastatic / unresectable GC receiving 2L treatment between January 2013 and July 2015 were enrolled. Patient characteristics, treatment patterns and clinical outcomes were captured for 12 months from the start of 2L treatment or until death. Results: 280 patients were included (mean age 60.9 years, 68.9% male). Half of the patients (51.8%) received monotherapy in 2L. Among these, taxanes were most prescribed (69.0%) followed by irinotecan (22.1%). Doublet chemotherapy was the most common combination therapy in 2L (75.6%) with fluoropyrimidine + irinotecan (33.3%) being the most used, followed by fluoropyrimidine + platinum (17.8%). Less than a third of patients (29.3%) received subsequent third-line (3L) treatment; 62.7% received monotherapy [mainly taxanes (69.2%) or irinotecan (19.2%)]. Most 3L patients who had combination therapy received a doublet (86.7%), most frequently fluoropyrimidine combined with irinotecan (53.3%) or platinum (20.0%). The majority of 2L patients (93.6%) had received combination therapy as first-line treatment, of whom 67.9% had received triplet chemotherapy, most commonly anthracycline + fluoropyrimidine + platinum (51.1%). Estimated median real-world progression free survival (PFS) and overall survival (OS) after 2L treatment initiation was 3.09 (95% CI: 2.76-3.68) and 6.54 (5.29-7.76) months, respectively, and estimated probability of PFS and OS at 12 months was 8% and 26%, respectively. Conclusions: The clinical management of advanced / metastatic GC patients in 2L treatment commonly involves taxanes or irinotecan as monotherapy, or irinotecan or platinum-based combinations with fluoropyrimidines. RW clinical outcomes for 2L treatment are similar to randomised controlled trials but remain poor.

Associations of incidence of common adverse events (AEs) and survival outcomes in metastatic colorectal cancer (mCRC) patients (pts) treated with first line chemotherapy: Findings from 9,812 pts in the ARCAD database

617

Background: There is limited, often conflicting evidence about AE timing, severity or associations with outcomes with the use of cytotoxic agents in cancer treatment. We investigated the impact on overall survival (OS) and progression-free survival (PFS) of selected common AEs (neutropenia, diarrhea, nausea, vomiting, neuropathy) occurring in patients receiving first line oxaliplatin (Oxa)- and/or irinotecan(Iri)-based regimens for mCRC. Methods: The CTCAE grading scores of at least one AE of interest were available on 9812 pts treated with chemotherapy alone (median age 63; 62.4% male, 50.1% ECOG PS 0) from 17 1st-line randomized trials. Patients who also received biologics were excluded in the primary analyses. AEs occurring during the first 6 weeks of treatment and entire treatment were analyzed by stratified multivariable Cox models in relationship to OS/PFS. 55.7% pts received Oxa- regimens, 35.7% Iri-regimens, and 8.6% combined Oxa- and Iri-regimens. Results: Within the first 6 weeks of treatment, G3+ neutropenia (HRadj= 1.3, 95% CI, 1.06-1.59, padj 0.01), diarrhea (HRadj= 1.48, 95% CI, 1.23-1.79, padj < .0001), nausea (HRadj= 1.53, 95% CI, 1.17-1.99, padj 0.002) and vomiting (HRadj= 1.56, 95% CI, 1.18-2.07, padj 0.002) were associated with significantly worse OS for Iri-regimens, but only G3+ nausea predicted for worse OS for Oxa- regimens (HRadj= 1.61, 95% CI, 1.18-2.21, padj 0.003). For AEs experienced at any time, G3+ neutropenia and neuropathy were significantly associated with longer PFS and OS for Oxa-regimens, while G3+ vomiting and nausea were associated with worse OS for both Oxa- and Iri-based regimens. Sensitivity analysis showed largely concordant results by including pts who also received biologics. Conclusions: The association between more severe selected AEs and outcome varies between AEs and is influenced by timing of the occurrence. More severe selected AEs occurring early in treatment are associated with worse outcomes. In contrast, for AEs occurring at any time, G3+ neutropenia and neuropathy predicted for longer PFS and/or OS in Oxa-treated pts.

Integrate II: A randomised phase 3 double-blind placebo-controlled study of regorafenib in refractory advanced gastro-oesophageal cancer (AGOC)—An international study organized by the Australasian Gastrointestinal Trials Group (AGITG)

TPS4136

Background: AGOC has a poor prognosis with no established standard treatment following failure of chemotherapy (CT). Regorafenib (BAY 73-4506)(REG) is an oral multi-kinase inhibitor targeting kinases involved in angiogenesis (VEGFR1-3, TIE-2), tumor microenvironment (PDGFR-β, FGFR), and oncogenesis (RAF, RET and KIT). INTEGRATE (phase 2) demonstrated REG was highly effective in prolonging PFS across a range of AGOC pts, with a positive OS trend. Regional differences were found in magnitude of effect, but REG was effective in all regions/subgroups. The phase 3 INTEGRATE II will explore whether REG is effective in prolonging survival in patients overall, and in the Asian sub-population. Methods: International (Australia/New Zealand (NHMRC CTC); Canada (CCTG), Korea, Japan, Taiwan, USA (ACCRU)) randomised phase III, double-blind, placebo-controlled trial with 2:1 (REG:placebo)(PBO) randomisation and stratification by: Location of tumour, Geographic region, prior VEGF inhibitors. Eligible patients (histologically confirmed AGOC), with evaluable metastatic or locally advanced disease refractory to, or relapsed following second line CT, will receive best supportive care plus 160mg REG or matched placebo orally on days 1-21 of each 28 day cycle until disease progression or prohibitive adverse events. Primary endpoint is OS. Secondary endpoints: PFS, response rate, quality of life, safety, identification of prognostic/predictive biomarkers for study endpoints, and REG PK across geographical regions. 350 patients (50% from Asia) randomized in a 2:1 ratio will provide 90% power to detect a hazard ratio (HR) for OS of 0.67 with a 2-sided α of 0.05 assuming PBO median survival is 4.5 mos. The sample size accommodates 2 interim analyses undertaken at 1/3 and 2/3 of required events. As of January 2017, 12 of 28 planned ANZ sites are open, with 4 patients enrolled. Regulatory approval has been received for 12 Canadian sites, and 12 Korean sites. Korean recruitment is expected to commence in February 2017. Regulatory submissions are pending in Taiwan, Japan, and the USA. Clinical trial information: NCT02773524.

Impact of overall severity of adverse events (AEs) on long-term outcomes in metastatic colorectal cancer (mCRC) patients (pts) treated with first line systemic chemotherapy: Findings from 3,971 pts in the ARCAD database

3582

Background: The prognostic importance of the incidence, severity, type and duration of AEs pts experience during chemotherapy varies between tumor types, and the available evidence across the board is often conflicting. Here we investigated the impact of the overall severity of AEs among pts with mCRC receiving first-line oxaliplatin (Oxa)- and/or irinotecan(Iri)-based regimens. Methods: The overall severity of AE data (i.e., max grade (G) of all AEs) were available on 3,971 pts (median age 61; 60% male, 47% ECOG PS 1+; 57% 2+ metastatic sites) enrolled onto 6 1st-line randomized trials. Around 46%, 45%, and 9% of pts had received Oxa-, Iri-, and Oxa+Iri-based regimens, respectively. Pts receiving biologic agents were excluded. Stratified multivariate Cox models were used to assess the associations with overall survival (OS) and progression-free survival (PFS); adjusted hazard ratios (HRadj) and 95% confidence intervals (CIs) are reported. Results: Pts who only received Oxa-based treatment reported the lowest rate of G3+ AEs (p < .0001) compared to pts treated with Iri- or Oxa+Iri-based regimens. Older age, female gender, and PS 1 or 2+ were associated with higher grade AEs (all p < .0001). Considering AEs experienced within 6w after randomization, 10% and 61% of pts experienced G4+ and G2-3 AEs, respectively. G3+ AEs were associated with a shorter OS for both pts receiving Oxa- (HRadj= 1.2, 95% CI, 1.1-1.3, padj < .0001) and Iri-based regimens (HRadj= 1.4, 95% CI, 1.2-1.5, padj < .0001). For the entire treatment course, 19% and 72% of pts experienced G4+ and G2-3 AEs, respectively. For Oxa-based regimens, pts with G3+ AEs had a longer OS (HRadj= 0.86, 95% CI, 0.78-0.94, padj = .0016), whereas G3+ AEs were associated with a shorter OS (HRadj= 1.2, 95% CI, 1.1-1.4, padj = .0004) for pts treated with Iri-based regimens. Similar patterns were seen for PFS. Conclusions: Pts who reported higher grade AEs during initial treatment (≤6w) have significantly worse outcome than those who do not. Further analyses with treatment exposure/detailed dose-AE profile and its impact on survival are warranted.

Efficacy and safety of ramucirumab (RAM) for metastatic gastric or gastroesophageal junction (GEJ) adenocarcinoma across age subgroups in two global phase 3 trials

3

Background: REGARD and RAINBOW are two phase 3 studies which demonstrated significant survival benefits and manageable toxicity in patients with advanced gastric cancer (GC) randomized in the second-line setting to receive RAM or placebo. We examined outcomes by age (≤45, 45-70, ≥70, ≥75 years). Methods: Patients were randomized 2:1 to receive RAM 8 mg/kg + best-supportive care (BSC) or placebo (PL) + BSC (REGARD); or 1:1 RAM 8 mg/kg + paclitaxel (PTX) or PL + PTX (RAINBOW). Kaplan-Meier analysis and Cox proportional hazards regression were performed for overall survival (OS) and progression-free survival (PFS). Subpopulation treatment effect pattern plot (STEPP) assessed efficacy and the incidence of adverse events (AEs) across age subgroups. Results: Baseline characteristics were generally well balanced between arms amongst the age subgroups. Efficacy outcomes are summarized in the Table. STEPP analysis revealed no obvious patterns for differential risks in terms of efficacy and AEs (any grade or grade ≥3) according to age. Conclusions: Compared with PL, the efficacy of RAM was maintained in all age groups, with similar rates of toxicity. Despite some limitations regarding patient numbers in some age subgroups, this exploratory subgroup analysis supports the use of RAM for the treatment of GC, irrespective of age. Clinical trial information: NCT00917384 and NCT01170663. [Table: see text]

Tumor-size-based endpoints as surrogates for overall survival in the ARCAD Advanced Colorectal Cancer Database

766

Background: Tumor-size-based endpoints such as depth of response have recently become a focus of investigations related to search for early on-treatment predictive markers for patients with colorectal cancer (Piessevaux et al. 2013; Cremolini et al., 2015; Heinemann et al., 2015). We evaluate the use of time-to-nadir (TTN) and depth-of-nadir (DoN) as potential surrogates for overall survival (OS). Methods: We have used the data from trials included in the ARCAD Advanced Colorectal Cancer Database. We have considered three sets of treatment comparisons: comparisons involving only chemotherapy agents (CT); involving anti-angiogenesic agents (ANG); and involving anti-EGFR agents (EGFR). For each of the sets separately, we applied a two-stage modelling approach (Renard et al. 2002) to jointly analyze the relative change of tumor size versus baseline (RCTS) and OS. In particular, in the first stage, a joint model for the repeated measurements of RCTS and OS was fitted to the data. Based on the model, treatment effects on OS and RCTS were estimated. Treatment effects on OS were expressed as log-hazard-ratios, while the effects on RCTS were expressed in terms of differences in the time-to-nadir (TTN) and in the depth of nadir (DoN). In the second stage, a linear regression was fitted through the estimated treatment effects on TTN/DoN and OS. The coefficient of determination (R2), computed by using the comparison-specific sample-size as weights, was used to quantify the strength of association between the treatment effects on TTN/DoN and OS. In particular, values of R2 larger than 0.75 were considered as indicating a good surrogate. Results: The CT set included 18 comparisons with 5726 pts. in total. For the treatment effects on TTN and OS, the value of R2 was estimated to be equal to 0.31, while for DoN and OS, it was equal to 0.01. For the ANG set (11 comparisons, 3964 pts.) the values of R2 were equal to 0.26 and 0.21, respectively, while for the EGFR set (16 comparisons, 4687 pts.) they were equal to 0.10 and 0.45, respectively. Conclusions: These preliminary results suggest that TTN and DoN are not good surrogates for OS in advanced colorectal cancer. More detailed analyses are ongoing and will be presented at the meeting.

TACTIC: a multicentre, open-label, single-arm phase II trial of panitumumab, cisplatin, and gemcitabine in biliary tract cancer

PURPOSE

The phase II TACTIC trial prospectively selected patients with KRAS wild-type advanced biliary tract cancer for first-line treatment with panitumumab and combination chemotherapy.

METHODS

Of 78 patients screened, 85 % had KRAS wild-type tumours and 48 were enrolled. Participants received cisplatin 25 mg/m(2) and gemcitabine 1000 mg/m(2) on day 1 and day 8 of each 21-day cycle and panitumumab 9 mg/kg on day 1 of each cycle. Treatment was continued until disease progression, unacceptable toxicity, or request to discontinue. The primary endpoint was the clinical benefit rate (CBR) at 12 weeks (complete response, partial response, or stable disease). CBR of 70 % was considered to be of clinical interest. Secondary outcomes were progression-free survival, time to treatment failure, overall survival, CA19.9 response and safety.

RESULTS

Thirty-four patients had a clinical benefit at 12 weeks, an actuarial rate of 80 % (95 % CI 65-89 %). 46 % had a complete or partial response. Median progression-free survival was 8.0 months (95 % CI 5.1-9.9) and median overall survival 11.9 months (95 % CI 7.4-15.8). Infection accounted for 27 % of the grade 3 or 4 toxicity, with rash (13 %), fatigue (13 %), and hypomagnesemia (10 %) among the more common grade 3 or 4 non-haematological toxicities.

CONCLUSION

A marker-driven approach to patient selection was feasible in advanced biliary tract cancer in an Australian population. The combination of panitumumab, gemcitabine, and cisplatin in KRAS wild-type cancers was generally well tolerated and showed promising clinical efficacy. Further exploration of anti-EGFR therapy in a more selected population is warranted.

Oxaliplatin and 5-FU/folinic acid (modified FOLFOX6) with or without aflibercept in first-line treatment of patients with metastatic colorectal cancer: the AFFIRM study

BACKGROUND

The combination of aflibercept with FOLFIRI has been shown to significantly prolong overall survival in patients with metastatic colorectal cancer (mCRC) after progression on oxaliplatin-based therapy. This trial evaluated the addition of aflibercept to oxaliplatin-based first-line treatment of patients with mCRC.

PATIENTS AND METHODS

Patients with mCRC were randomized to receive first-line therapy with mFOLFOX6 plus aflibercept (4 mg/kg) or mFOLFOX6 alone. The primary end point of this phase II study was the progression-free survival (PFS) rate at 12 months in each arm. The analysis of efficacy between the arms was a pre-planned secondary analysis.

RESULTS

Of 236 randomized patients, 227 and 235 patients were evaluable for the primary efficacy analysis and safety, respectively. The probabilities of being progression-free at 12 months were 25.8% [95% confidence interval (CI) 17.2-34.4] for the aflibercept/mFOLFOX6 arm and 21.2% (95% CI 12.2-30.3) for the mFOLFOX6 arm. The median PFS was 8.48 months (95% CI 7.89-9.92) for the aflibercept/mFOLFOX6 arm and 8.77 months (95% CI 7.62-9.27) for the mFOLFOX6 arm; the hazard ratio of aflibercept/mFOLFOX6 versus mFOLFOX6 was 1.00 (95% CI 0.74-1.36). The response rates were 49.1% (95% CI 39.7-58.6) and 45.9% (95% CI 36.4-55.7) for patients treated with and without aflibercept, respectively. The most frequent treatment-emergent grade 3/4 adverse events (AEs) excluding laboratory abnormalities reported for aflibercept/mFOLFOX6 versus mFOLFOX6 were neuropathy (16.8% versus 17.2%) and diarrhea (13.4% versus 5.2%). Neutropenia grade 3/4 occurred in 36.1% versus 29.3%. The most common vascular endothelial growth factor inhibition class-effect grade 3/4 AEs for aflibercept/mFOLFOX6 versus mFOLFOX6 were hypertension (35.3% versus 1.7%), proteinuria (9.2% versus 0%), deep vein thrombosis (5.9% versus 0.9%) and pulmonary embolism (5.9% versus 5.2%).

CONCLUSION

No difference in PFS rate was observed between treatment groups. Adding aflibercept to first-line mFOLFOX6 did not increase efficacy but was associated with higher toxicity.

CLINICAL TRIAL NUMBER

NCT00851084, www.clinicaltrials.gov, EudraCT 2008-004178-41.

Evaluation of circulating VEGF based biomarkers in INTEGRATE: A randomized phase II double-blind placebo-controlled study of regorafenib in refractory advanced oesophagogastric cancer (AOGC)—A study by the Australasian Gastrointestinal Trials Group (AGITG)

64

Background: The INTEGRATE study evaluated activity of regorafinib (REG) v placebo (PBO) in 147 eligible patients with refractory AOGC. REG was highly effective in prolonging progression free survival (PFS). Differences between regions (i.e. Australia New Zealand/Canada (ANZ/CAN) vs Korea) were found in the magnitude of effect, but REG was effective across all regions and subgroups. We report on an exploratory analysis of VEGF biomarkers to identify predictive/prognostic markers. Methods: Protein biomarkers IL8, VEGF-A,-B,-C-D, soluble(s)VEGFR-1,-2-3 were analysed in plasma at baseline (BL) by multiplex immunoassays (Bio-Plex,BioRad) or ELISA (Abnova). Spearman statistics were used to quantify correlations between markers. Wilcoxon Rank-Sum tests were used to compare markers across regions. The prognostic and predictive value of markers was determined using cox proportional hazards analysis of PFS. Results: There were moderate-to-strong correlations between BL levels of IL8 and VEGF-C (ρ = 0.68), IL8 and VEGF-D (ρ = 0.66), VEGF-A and VEGF-C (ρ = 0.68), VEGF-A and sVEGFR-1 (ρ = 0.54); and a modest negative correlation between VEGF-D and sVEGRF-1 (ρ = -0.33). The regions differed according to BL levels of: VEGF-A (higher in ANZ/CAN; p = 0.0015), VEGF-B (higher in Korea; p = 0.0003), VEGF-D (higher in Korea; p <.0001), and sVEGFR-1 (higher in ANZ/CAN; p <.0001). Adjusting for treatment group, there were statistically significant negative associations between PFS and BL IL8 (p = 0.047), VEGF-A (p = 0.037) and sVEGFR-1 (p = 0.045). There was no convincing statistical evidence that any BL plasma biomarker modified the effect of REG. The effect of region on effectiveness of REG was maintained when evaluated in conjunction with BL biomarkers individually and in combination. Conclusions: Highplasma IL8, VEGF-A and sVEGFR-1 may be adverse prognostic factors. A predictive VEGF blood based biomarker remains elusive. A broader biomarker study including markers beyond the VEGF axis and tissue based markers is ongoing. Clinical trial information: ACTRN12612000239864.

Location of colon cancer (right-sided versus left-sided) as a prognostic factor and a predictor of benefit from cetuximab in NCIC CO.17

BACKGROUND

Right- and left-sided colon cancers (RC, LC) differ with respect to biology, pathology and epidemiology. Previous data suggest a mortality difference between RC and LC. We examined if primary tumour side also predicts for outcome in chemotherapy refractory, metastatic colon cancer (MCC). We also compared RC versus LC as a predictor of efficacy of epidermal growth factor receptor (EGFR) inhibition with cetuximab.

METHODS

Reanalyzing NCIC CO.17 trial (cetuximab versus best supportive care [BSC]), we coded the primary tumour side as RC (caecum to transverse colon) or LC (splenic flexure to rectosigmoid). The association between tumour side and baseline characteristics was assessed. Cox regression models determined factors affecting overall survival (OS) and progression free survival (PFS).

RESULTS

Patients with RC (150/399) had more poorly differentiated, mutant KRAS, mutated PIK3CA and wild-type BRAF tumours, fewer liver and lung metastases, and shorter interval between diagnosis and study entry. Among BSC patients, tumour side was not prognostic for PFS (hazard ratios (HR) 1.07 [0.79-1.44], p = 0.67) or OS (HR 0.96 [0.70-1.31], p = 0.78). Among wild-type KRAS patients, those with LC had significantly improved PFS when treated with cetuximab compared to BSC (median 5.4 versus 1.8 months, HR 0.28 [0.18-0.45], p < 0.0001), whereas those with RC did not (median 1.9 versus 1.9 months, HR 0.73 [0.42-1.27], p = 0.26), [interaction p = 0.002].

CONCLUSION

In refractory MCC, tumour location within the colon is not prognostic, but is strongly predictive of PFS benefit from cetuximab therapy. Additional research is needed to understand the molecular differences between RC and LC and their interaction with EGFR inhibition.

INTEGRATE: A randomized phase II double-blind placebo-controlled study of regorafenib in refractory advanced oesophagogastric cancer (AOGC)—A study by the Australasian Gastrointestinal Trials Group (AGITG), first results

9

Background: Advanced Oesophago-Gastric Carcinoma (AOGC) has limited options following failure of first or second line chemotherapy (CT). Regorafenib (REG) is an oral multi-kinase inhibitor of kinases involved in angiogenesis, tumor microenvironment, and oncogenesis. This study examined whether REG has sufficient activity and safety for further evaluation. Methods: International (Australia & New Zealand (ANZ), Korea, Canada (NCIC CTG)) randomised phase II trial with 2:1 randomisation and stratification by: (1) Lines of prior CT for advanced disease (1 vs. 2) and (2) Region. Eligible patients received best supportive care plus 160mg REG or matching PBO orally on days 1-21 each 28-day cycle until disease progression or prohibitive adverse events. Primary endpoint was progression free survival (PFS) in the REG arm, assuming median 8 weeks (wks) in PBO arm, aiming for 13.2 wks with REG to be of interest. Results: From Nov 2012 to Feb 2014, 152 patients were enrolled, 147 evaluable [pre-specified primary analysis population]: (REG n=97: PBO n=50); well matched for key baseline prognostic indicators; male:female (118:29); primary location: OG Junction (56), stomach (85); lines of prior therapy: 1 (63), 2 (84); ECOG 0 (62): 1 (85). Time on treatment: Median: 7.9 (REG) v 4 (PBO) wks. In the evaluable population median PFS was 11.1 wks (95% CI: 7.7 - 12.3) (REG) and 3.9 wks (95% CI: 3.7 - 4.0) (PBO), log-rank p <0.0001; HR 0.41 (95% CI: 0.28 to 0.59). PFS results were maintained for secondary analysis including all randomized patients (n = 152). REG was well tolerated, with the spectrum of toxicity in keeping with previous reports. Conclusions: PFS was clearly significantly longer with REG than PBO, though PBO PFS was less than anticipated. The pre-specified exploratory comparisons provide compelling evidence that REG has sufficient activity with acceptable tolerability in refractory AOGC to warrant phase III evaluation. Mature OS results will be presented at the meeting. Clinical trial information: 12612000239864.

Nomograms for overall survival (OS) and progression-free survival (PFS) in metastatic colorectal cancer (mCRC): Construction from 19,678 ARCAD patients

659

Background: Prospective survival prediction of patients with metastatic colorectal cancer is difficult. Prognosis estimation based on readily available clinicopathologic factors has the potential to inform clinical practice and improve risk stratification for clinical trials. We constructed prognostic nomograms for OS and PFS in mCRC using the multi-trial ARCAD database. Methods: Data from 19,678 mCRC pts accrued to 24 first line randomized phase III clinical trials since 1997 were used to construct and validate Cox models for PFS and OS, stratified by treatment arm within each study. Candidate variables included age, gender, BMI, performance status, colon vs. rectal cancer, prior chemotherapy, number of metastatic sites, sites of metastases (liver, lung, lymph nodes), and baseline bilirubin, albumin, white blood cell count, hemoglobin, platelets, absolute neutrophil count, and derived neutrophil:lymphocyte ratio (dNLR). Missing data (<11%) were imputed, continuous variables modeled with splines, and clinically relevant pairwise interactions considered if p<0.001. Final models were internally validated via bootstrapping to obtain optimism-corrected calibration and discrimination C-indices, and externally validated using a 10% holdout sample from each trial. Results: Nomograms for OS and PFS including remaining variables were well calibrated with C-indices of 0.66 and 0.60, respectively. Evaluation of external validity revealed good concordance; 71% and 67% respectively between predicted (> vs. <50% probability) and actual (yes/no) 1-year OS and 6-month PFS, and median 1-year OS and 6-month PFS predictions fell within the actual 95% Kaplan-Meier intervals. Gender, liver and lung metastases, and dNLR were not prognostic for OS; prior chemo, colon vs. rectum, dNLR, liver and lymph node metastases, and gender did not predict for PFS. No clinically relevant pairwise interactions were identified. Conclusions: The proposed nomograms are well calibrated and internally and externally valid. These tools have the potential to aid prognostication and patient/physician communication, and balance risk in randomized trials in mCRC.

Trial-level association between response-based endpoints (RBEs) and progression-free (PFS)/overall survival (OS) in first-line therapy for metastatic colorectal cancer (mCRC) in the ARCAD database

666

Background: Early tumor shrinkage (ETS; ≥20% decrease from baseline) and early objective tumor response (EOTR; CR/PR by RECIST) are associated with improved PFS/OS to a similar extent than best overall response (BOR), confirmed response (ConfR) and non-progression rate (NPR; CR/PR/SD by RECIST) at the individual level in first-line mCRC (ASCO 2014, abstr 3538/3578). We assessed these RBEs at the trial level. Methods: Data were available on 12,185 pts enrolled in a total of 17 randomized trials of chemotherapy (CT) alone or with targeted agents (TAs). ETS, EOTR and NPR were assessed at 6/8/9 and 12 weeks (wks), whereas BOR and ConfR were ascertained within 26 wks from randomization. Association between treatment effects on RBEs and on PFS/OS was assessed by coefficients of determination (R2, adjusted for estimation errors) using a copula model). Results: None of the RBEs had consistently strong correlations with PFS or OS (Table). The number of trials was insufficient to obtain reliable estimates for antiangiogenics and anti-EGFR separately. Conclusions: Despite their individual-level associations with PFS and OS, RBEs do not appear to be surrogate endpoints in first-line mCRC, given their poor predictive ability. [Table: see text]