Citations

PURPOSE CALGB (Alliance)/SWOG 80405 was a randomized phase III trial that in first-line patients with metastatic colorectal cancer (mCRC) treated with bevacizumab or cetuximab with chemotherapy. We aimed to discover novel mutated genes associated with prognosis and differential response to therapy with the biologics. METHODS Primary tumor DNA from 548 patients was sequenced using FoundationOne. The effect of mutated genes and mutations on overall survival (OS) was tested adjusting for microsatellite instability status, BRAF V600E, all RAS mutations, arm, sex, and age. RESULTS The median number (lower-upper quartile) of mutated genes was 5 (3-7), 5 (3-6) in microsatellite stable and 12.5 (4.5-32) in microsatellite instability-high tumors. Mutated KRAS and APC were more frequent in Black (53% and 85%) than White (27% and 65%, respectively) patients while BRAF V600E was less frequent in Black (5%) than White (14%) patients. The median OS in patients with BRAF non-V600E (2.2% of patients) was 31.9 months (95% CI, 15.1 to not applicable [NA]) similar to that of BRAF wild-type (WT) patients (31.2 months [95% CI, 29.0 to 33.9]). Mutated LRP1B (10.7% of patients) was associated with improved OS compared with WT LRP1B (hazard ratio, 0.57 [95% CI, 0.40 to 0.80]). RNF43 (5.6% of patients) interacted with treatment arms as, in the cetuximab arm, patients with mutated RNF43 had a median OS of 11.5 (95% CI, 10.8 to NA) months compared with 30.1 (95% CI, 24.9 to 35.3) months in patients with WT RNF43, whereas in the bevacizumab arm, patients with mutated RNF43 had a median OS of 25.0 (95% CI, 14.2 to NA) months compared with 31.3 (95% CI, 29.0 to 34.3) months in patients with WT RNF43. CONCLUSION These results can provide new tools to predict patient outcome and improve therapeutic decisions and trial participation in patient minorities. The molecular alterations identified in this study may direct biomarker-driven studies.

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co‐primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported. Acquired genomic alterations (Acq-GAs), specifically RAS, BRAF, and EGFR-ectodomain mutations and ERBB2 and MET amplifications, are recognized as major mechanisms of resistance to later-line anti–EGFR-antibody therapy in metastatic colorectal cancer (mCRC). However, data regarding emergence of these Acq-GAs under the selective pressure of first-line anti–EGFR-chemotherapy are lacking. We performed next-generation sequencing (Guardant360) on circulating tumor DNA obtained from paired plasma samples (pretreatment and postprogression) from the CALGB/SWOG-80405 trial, which randomly assigned patients with mCRC between first-line chemotherapy with cetuximab (anti–EGFR-chemotherapy) or bevacizumab (anti–VEGF-chemotherapy). The primary objective was to determine the prevalence of Acq-GAs on anti–EGFR-chemotherapy and compare this to the prevalence with anti–VEGF-chemotherapy on trial and pooled estimates (N = 292) seen with later-line anti–EGFR-antibody therapy as reported in the literature. Among the 61 patients on anti–EGFR-chemotherapy, only four (6.6%) developed ≥ 1 Acq-GAs of interest compared with 10.1% (7) on anti–VEGF-chemotherapy (odds ratio, 0.62; 95% CI, 0.20 to 2.11) and 62.0% on anti–EGFR-antibody therapy in later lines (odds ratio, 0.09; 95% CI, 0.03 to 0.23). Acq-GAs, classically associated with anti–EGFR-antibody resistance in later lines ( RAS, BRAF, and EGFR-ectodomain mutations; ERBB2 and MET amplifications), were rare with up-front use of anti–EGFR-chemotherapy indicating divergent resistance mechanisms. These findings have critical translational relevance to timing and value of circulating tumor DNA–guided anti-EGFR rechallenge in patients with mCRC, especially those treated with anti-EGFR therapy upfront.

Abstract Genetic variants in the DPYD gene that are deleterious to dihydropyrimidine dehydrogenase (DPD) enzyme function have demonstrated clinical validity as predictive biomarkers for severe (i.e., CTCAE grade ≥3) and potentially lethal toxicity to fluorouracil (5-FU) and capecitabine chemotherapies. Variants within the coding region only explain 5-10% of 5-FU-related toxicities; and GWAS approaches have been unable to identify validated predictive biomarkers to date. Our previous studies demonstrated that DPD expression was controlled by multiple epigenetic processes; considerable variation was also noted in liver DPYD/DPD levels. Using CRISPR-interference (CRISPRi) and CRISPR-activation (CRISPRa), we identified functional enhancer regions within liver tissues and cells. Epigenetic status at these regions was shown to correlate with DPYD expression in cell models and human liver tissues. Chromosome conformation capture (3C) confirmed direct promoter-enhancer interactions. A multi-omics analysis of >1000 human liver specimens identified a proximal eQTL for DPYD expression within an enhancer, with a global minor allele frequency of 27%. This variant was subsequently shown to directly alter DPYD expression in knock-in cell line models. The variant disrupts transcription factor binding at the DPYD enhancer, leading to reduced enhancer-promoter interaction, reduced DPD expression, and increased cellular sensitivity to 5-FU. Collectively, our data suggest that the variant could represent a novel predictive biomarker for severe 5-FU toxicity. The evaluation of this marker in the clinical setting is currently underway. Citation Format: Ting Zhang, Alisa Ambrodji, Huixing Huang, Kelly Bouchonville, Amy Etheridge, Remington Schmidt, Jose Cardiel Nunez, Zoey Temesgen, Federico Innocenti, Robert Diasio, Carlo Largiadèr, Steven M. Offer. DPYD enhancer variant confers increased risk of severe toxicity in 5-FU chemotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5420.

3586 Background: HSP90 mediated chaperoning is a well-conserved biological mechanism for stabilization and activation of kinases. More than 60% of human kinases including VEGFR, CRAF, CSF1R, and FGFR are target of HSP90 (client kinases), whereas EGFR is non-client. CDC37 is a specific co-chaperone determining selectivity of client kinases recognized by HSP90. We hypothesized that gene expression levels of CDC37 have predictive values for anti-angiogenic therapies in mCRC. Methods: The subjects of this study were mCRC patients treated with regorafenib (REGO, Japanese retrospective cohort) and those treated with bevacizumab (BEV) or cetuximab (CET) in combination with first-line chemotherapy (CALGB/SWOG 80405 trial cohort). CDC37 expression levels were measured using RNA isolated from FFPE samples by nCounter gene expression profiling (Nanostring) and HiSeq 2500 (Illumina) in the Japanese and CALGB/SWOG 80405 cohorts, respectively. Overall survival (OS) and progression-free survival (PFS) were compared between patients with high CDC37 expression ( CDC37-H) and those with low expression ( CDC37-L), grouped by median cutoff value in each cohort. Results: In total, 484 patients were included (50 treated with REGO, 227 treated with BEV, and 207 treated with CET). In REGO-treated patients, CDC37-H showed significantly better OS (median 11.3 vs 6.0 months, adjusted hazard ratio [HR] 0.24, 95% confidence interval [CI] 0.11-0.54, p <0.01) and PFS (median 3.5 vs 1.9 months, adjusted HR 0.51, 95% CI 0.28-0.94, p = 0.03) compared to CDC37-L. Similarly, in BEV-treated patients, CDC37-H showed significantly better PFS (median 13.5 vs 9.6 months, adjusted HR 0.59, 95% CI 0.43-0.79, p <0.01) and numerically better OS (median 34.1 vs 29.4 months, adjusted HR 0.81, 95% CI 0.60-1.11, p = 0.20) compared to CDC37-L. However, in CET-treated patients, CDC37-H and CDC37-L patients showed similar OS (median 33.7 vs 26.1 months, adjusted HR 1.00, 95% CI 0.73-1.38, p = 0.98) and PFS (median 11.3 vs 11.0 months, adjusted HR 1.08, 95% CI 0.81-1.45, p = 0.60). Significant interaction was observed between CDC37 expression and treatment in terms of PFS in the CALGB/SWOG 80405 cohort ( p = 0.01). Conclusions: Our results suggest patients with CDC37-dependent ( CDC37-H) tumors may derive more benefit from REGO and BEV both of which target HSP90 client kinases or signaling pathways, but not from CET which target HSP90 non-client kinase. Further validation studies are warranted to develop a novel personalized approach for targeted therapies based on CDC37 expression in mCRC patients. Support: U10CA180821, U10CA180888; Pfizer, Genentech; https://acknowledgments.alliancefound.org. ClinicalTrials.gov Identifier: NCT00265850.

3580 Background: Monoamine oxidases (MAOs), including MAOA and MAOB, are mitochondrial enzymes responsible for catalyzing monoamine oxidation. Increased expression of MAOs were found in several cancer types and high MAOB was associated with worse disease stage and poorer survival in CRC. Positive and negative correlations of MAOB expression with mesenchymal type and epithelial type gene expressions, respectively, have been reported. Hence, we investigated whether MAOB expression is predictive for targeted therapies in mCRC. Methods: 430 mCRC pts treated with either bevacizumab (BEV, n = 224) or cetuximab (CET, n = 206) in combination with first-line chemotherapy within the CALGB/SWOG 80405 trial were included in the analysis. MAOB RNA was isolated from FFPE tumor samples and sequenced on the HiSeq 2500 (Illumina). Overall survival (OS) and progression-free survival (PFS) were compared between groups of pts categorized by tertiles of MAOB expression into high (H), medium (M) and low (L). Hazard ratios (HR) and 95% confidence intervals (CI) were computed from multivariable Cox proportional hazards model, adjusting for age, sex, location, number of metastases, KRAS, MSI status, and treatment with FOLFOX or FOLFIRI. Sensitivity analyses were conducted after stratifying by sex. Logrank P-values describe differences without adjustment for patient characteristics. Results: In CET-treated pts, MAOB-L showed significantly longer OS (median 39.2 vs 30.9 vs 15.9 months, logrank P = 4.7E-05, L vs H (as reference) adjusted HR 0.42, 95% CI [0.27, 0.65]) and PFS (median 13.2 vs 11.8 vs 7.6 months, logrank P = 0.006, L vs H adjusted HR 0.59 [0.40, 0.88]) compared to MAOB-M and MAOB-H, respectively. Similar results were observed when evaluating MAOB expression as a continuous variable. In BEV-treated pts, no significant differences were observed when comparing MAOB expression tertiles; however, pts with lower MAOB expression had significantly better OS, but not PFS, when evaluating MAOB as a continuous variable (Cox LRT P = 0.015, covariate adjusted). In CET-treated pts, the effect of MAOB expression was observed in male but not female pts (OS: median 40.3 vs 30.9 vs 16.1 months by MAOB-L, M, H, respectively, logrank P = 6.8E-05, L vs H adjusted HR 0.33 [0.19, 0.59]; PFS: median 13.8 vs 12.6 vs 7.9 months, logrank P = 0.001, L vs H adjusted HR 0.46 [0.28, 0.79]). A significant interaction was observed between MAOB expression and treatment for OS ( P = 0.010) in males and females combined, but only in males ( P = 0.018) when stratified by sex. Conclusions: Our results suggest that pts with MAOB-L tumors may have greater benefit from CET-based treatment and that targeting MAOB may be a promising strategy to improve patient outcomes. Further validation studies are warranted to develop a novel personalized approach based on MAOB expression in mCRC pts. Clinical trial information: NCT00265850.

Hypertension is a common bevacizumab‐induced toxicity. No markers are available to predict patients at risk of developing hypertension. We hypothesized that genetic risk of essential hypertension, as measured by a blood pressure polygenic risk score (PRS), would be associated with risk of severe bevacizumab‐induced hypertension. PRSs were calculated for 1,027 bevacizumab‐treated patients of European descent with cancer from four clinical trials (Alliance for Clinical Trials in Oncology (Alliance) / Cancer and Leukemia Group B (CALGB) 80303, 40503, 90401, 40502) using summary systolic blood pressure (SBP) and diastolic blood pressure (DBP) genome‐wide association results obtained from 757,601 individuals of European descent. The association between PRS and grade 3 bevacizumab‐induced hypertension (Common Toxicity Criteria for Adverse Events version 3) in each trial was performed by multivariable logistic regression. Fixed‐effect meta‐analyses odds ratios (ORs) per standard deviation (SD) of the association of PRS (quantitative) and hypertension across trials were estimated by inverse‐variance weighting. PRSs were additionally stratified into quintiles, with the bottom quintile as the referent group. The OR of the association between hypertension and each quintile vs. the referent group was determined by logistic regression. The most significant PRS (quantitative)‐hypertension association included up to 67 single‐nucleotide variants (SNPs) associated with SBP (P = 0.0077, OR per SD = 1.31, 95% confidence interval (CI), 1.07–1.60), and up to 53 SNPs associated with DBP (P = 0.0209, OR per SD = 1.27, 95% CI, 1.04–1.56). Patients in the top quintile had a higher risk of developing bevacizumab‐induced hypertension compared with patients in the bottom quintile using SNPs associated with SBP (P = 4.75 × 10−4, OR = 3.72, 95% CI, 1.84–8.16) and DBP (P = 0.076, OR = 1.83, 95% CI, 0.95–3.64). Genetic variants associated with essential hypertension, mainly SBP, increase the risk of severe bevacizumab‐induced hypertension.

Abstract Purpose: CALGB/SWOG 80405 was a randomized phase III trial in first-line patients with metastatic colorectal cancer treated with bevacizumab, cetuximab, or both, plus chemotherapy. We tested the effect of tumor immune features on overall survival (OS). Experimental Design: Primary tumors (N = 554) were profiled by RNA sequencing. Immune signatures of macrophages, lymphocytes, TGFβ, IFNγ, wound healing, and cytotoxicity were measured. CIBERSORTx scores of naive and memory B cells, plasma cells, CD8+ T cells, resting and activated memory CD4+ T cells, M0 and M2 macrophages, and activated mast cells were measured. Results: Increased M2 macrophage score [HR, 6.30; 95% confidence interval (CI), 3.0–12.15] and TGFβ signature expression (HR, 1.35; 95% CI, 1.05–1.77) were associated with shorter OS. Increased scores of plasma cells (HR, 0.55; 95% CI, 0.38–0.87) and activated memory CD4+ T cells (HR, 0.34; 95% CI, 0.16–0.65) were associated with longer OS. Using optimal cutoffs from these four features, patients were categorized as having either 4, 3, 2, or 0–1 beneficial features associated with longer OS, and the median (95% CI) OS decreased from 42.5 (35.8–47.8) to 31.0 (28.8–34.4), 25.2 (20.6–27.9), and 17.7 (13.5–20.4) months respectively (P = 3.48e–11). Conclusions: New immune features can be further evaluated to improve patient response. They provide the rationale for more effective immunotherapy strategies.

193 Background: Enhanced understanding of the evolving clonal architecture under treatment stress is crucial to optimizing care and developing effective therapies in metastatic colorectal cancer (mCRC). Emergence of genomic alterations (GAs) [mutations (muts) and amplifications (amps)] in RAS, BRAF, EGFR, ERBB2, and MET have been recognized as key resistance mechanisms to anti-EGFR therapy in later lines in mCRC. Data regarding occurrence of these GAs under selective pressure in the first line setting is lacking. Methods: CALGB/SWOG 80405 was a randomized trial of bevacizumab (bev) vs cetuximab (cet) in first line mCRC. Patients (pts) with paired plasma samples (pre-treatment and post-progression) available for circulating tumor DNA (ctDNA) testing were included in this substudy. Sequencing of ctDNA was performed by Guardant360 assay in a CLIA-certified environment to detect GAs in 73 genes. RAS/BRAF status [mut vs. wild type (wt)] was based on clonal muts [pre-defined cutoff of relative MAF (rMAF) ≥ 25%] in ctDNA. Only samples with ≥1 GA were analyzed to minimize false negatives. The primary objective was to determine and compare prevalence of acquired GAs between study arms: bev (anti-VEGF) and cet (anti-EGFR). Descriptive statistics and Fisher’s exact test were used. Results: Baseline characteristics of ctDNA cohort were similar to the 80405 population. Among 133 randomized RAS/BRAF wt pts, 11 (15.3%) and 5 (8.2%) developed acquired GAs (OR 2.0, P = 0.29), in bev and cet arm, respectively. Key comparative data for pts with regard to acquired pathogenic GAs are shown in the table. Conclusions: In this randomized mCRC cohort, the ctDNA profile of acquired GAs with front line anti-EGFR chemotherapy appears to be strikingly distinct from that seen with later lines of therapy. Acquisition of GAs, classically associated with EGFR resistance in later line, was not only rare with upfront cet-chemotherapy but also comparable to bev-containing (anti-VEGF) regimen. The mechanisms of acquired resistance appear to differ when anti-EGFR therapy is administered in combination with highly active first line chemotherapy. Our findings have critical translational relevance to the timing and value of ctDNA-guided anti-EGFR rechallenge in mCRC pts, especially in those treated with anti-EGFR therapy upfront.[Table: see text]

Abstract Background The incidence of young-onset colorectal cancer (yoCRC) is increasing. It is unknown if there are survival differences between young and older patients with metastatic colorectal cancer (mCRC). Methods We studied the association of age with survival in 2326 mCRC patients enrolled in the Cancer and Leukemia Group B and SWOG 80405 trial, a multicenter, randomized trial of first-line chemotherapy plus biologics. The primary and secondary outcomes of this study were overall survival (OS) and progression-free survival (PFS), respectively, which were assessed by Kaplan-Meier method and compared among younger vs older patients with the log-rank test. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated based on Cox proportional hazards modeling, adjusting for known prognostic variables. All statistical tests were 2-sided. Results Of 2326 eligible subjects, 514 (22.1%) were younger than age 50 years at study entry (yoCRC cohort). The median age of yoCRC patients was 44.3 vs 62.5 years in patients aged 50 years and older. There was no statistically significant difference in OS between yoCRC vs older-onset patients (median = 27.07 vs 26.12 months; adjusted HR = 0.98, 95% CI = 0.88 to 1.10; P = .78). The median PFS was also similar in yoCRC vs older patients (10.87 vs 10.55 months) with an adjusted hazard ratio of 1.02 (95% CI = 0.92 to 1.13; P = .67). Patients younger than age 35 years had the shortest OS with median OS of 21.95 vs 26.12 months in older-onset patients with an adjusted hazard ratio of 1.08 (95% CI = 0.81 to 1.44; Ptrend = .93). Conclusion In this large study of mCRC patients, there were no statistically significant differences in survival between patients with yoCRC and CRC patients aged 50 years and older.