Amphiregulin Expression Is a Predictive Biomarker for EGFR Inhibition in Metastatic Colorectal Cancer: Combined Analysis of Three Randomized Trials

PURPOSE

Amphiregulin (AREG) and epiregulin (EREG) are ligands of EGFR. Predictive information for anti-EGFR treatment in metastatic colorectal cancer (mCRC) was observed, but data for other agents is limited.

EXPERIMENTAL DESIGN

Ligand mRNA expression; RAS, BRAF, PIK3CA mutations; and EGFR expression were assessed by qRT-PCR, pyrosequencing, and IHC, respectively, in mCRC tumor tissue of patients participating in the randomized controlled trials FIRE-1, CIOX, and FIRE-3. Normalized mRNA expression was dichotomized using median and third quartile. Overall (OS) and progression-free survival (PFS) were estimated by Kaplan-Meier method including univariate and multivariate Cox regression analyses. Penalized spline regression analysis tested interaction of mRNA expression and outcome.

RESULTS

Of 688 patients with available material, high AREG expression was detected in 343 (>median) and 172 (>3rd quartile) patients. High AREG expression was associated with significantly higher OS [26.2 vs. 21.5 months, HR = 0.80; 95% confidence interval (CI), 0.68-0.94; P = 0.007], PFS (10.0 vs. 8.1 months, HR = 0.74; 95% CI, 0.63-0.86; P = 0.001), and objective response rate (63.1% vs. 51.6%, P = 0.004) compared to low expression at both threshold values. This effect remained significant in multivariate Cox regression analysis (OS: P = 0.01, PFS: P = 0.002). High AREG mRNA expression interacted significantly with the efficacy of cetuximab compared with bevacizumab (OS: P = 0.02, PFS: P = 0.04) in RAS WT mCRC.

CONCLUSIONS

High AREG mRNA expression is a favorable prognostic biomarker for mCRC which interacted significantly with efficacy of anti-EGFR treatment.

High amphiregulin mRNA expression is a strong prognostic biomarker with response to cetuximab in FIRE-1, CIOX, and FIRE-3

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Background: Amphiregulin ( AREG) and epiregulin ( EREG) were discussed as biomarkers for treatment of metastatic colorectal cancer (mCRC). Data from randomized controlled trials (RCT) are limited. Methods: AREG and EREG mRNA expression by RTqPCR in relation to housekeeping genes were available from 688 patients of three RCT (FIRE-1, n = 192, FUFIRI vs. mIrOx; CIOX, n = 113, cetuximab + CAPIRI/CAPOX; FIRE-3, n = 383, FOLFIRI+cetuximab/bevacizumab) and were normalized to their respective range of each trial with median and 3rd quartile as threshold values. Kaplan-Meier estimated overall survival (OS) and progression-free survival (PFS). Cox regression analysis calculated hazard ratio (HR) and 95% confidence interval (95% CI). Overall response rate (ORR) was compared by chi square test. Results: Across all trials, high AREG mRNA expression appeared as strong prognostic biomarker for OS, PFS and ORR for all threshold values. In RAS wildtype patients, high AREG expression was associated with better OS and PFS for cetuximab but not bevacizumab treatment. (Table) No effects were seen for epiregulin when all trials were analysed together. Conclusions: High AREG mRNA expression appeared as strong prognostic biomarker in mCRC. Positive predictive information might exist for cetuximab treatment. [Table: see text]

Prognostic value of cetuximab-related skin toxicity in metastatic colorectal cancer patients and its correlation with parameters of the epidermal growth factor receptor signal transduction pathway: results from a randomized trial of the GERMAN AIO CRC Study Group

Skin toxicity is a frequent adverse event of epidermal growth factor receptor (EGFR) targeting agents. Occurrence of cetuximab-induced skin toxicity (Cet-ST) correlates with better treatment response and longer survival times. Molecular markers predicting Cet-ST are still missing. This investigation analyzed the value of Cet-ST for treatment efficacy in a randomized trial comparing cetuximab plus capecitabine/irinotecan to cetuximab plus capecitabine/oxaliplatin as first-line treatment of metastatic colorectal cancer. Patient characteristics and molecular parameters (KRAS mutation, EGFR-FISH, EGFR-IHC and EGFR intron-1 polymorphism) of the tumour were correlated with response and Cet-ST. Cet-ST grade 0-1 was observed in 31%, grade 2-3 in 69% of patients. Outcome favoured patients with grade 2-3 Cet-ST with regard to overall response rate (62 vs. 41%), PFS (7.8 vs. 5.2 months) and overall survival (OS) (30.3 vs. 18.0 months). First-cycle rash was observed in 66% of patients and corresponded with longer survival (30.7 vs. 20.2 months, p = 0.007). Patients without Cet-ST had a poor outcome (PFS, 1.9 months; OS, 11 months). The correlation of Cet-ST with survival was specifically evident in patients with KRAS codon-12-mutated tumours assumed to be cetuximab resistant. In multivariate analysis of patient characteristics, male gender and younger age were significantly correlated with Cet-ST. Among molecular parameters, no significant correlation with Cet-ST was found. Cet-ST is an early predictor of treatment efficacy in cetuximab-treated patients. This effect of Cet-ST is independent of the KRAS mutation status, suggesting that Cet-ST rather relates to constitutional factors of the patient than alterations of the EGFR pathway in the tumour.

Ligand expression of the EGFR ligands amphiregulin, epiregulin, and amplification of the EGFR gene to predict for treatment efficacy in KRAS wild-type mCRC patients treated with cetuximab plus CAPIRI and CAPOX: Analysis of the randomized AIO CRC-0104 trial

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Background: We investigated the expression of the EGFR ligands amphiregulin (AREG) and epiregulin (EREG) as well as the amplification of the EGFR-gene in tumor specimens of mCRC patients (pts) treated first-line with anti-EGFR targeted cetuximab together with CAPOX or CAPIRI. Expression levels were correlated with overall response rate (ORR), progression free survival (PFS) and overall survival (OS) to determine their relationship with effectiveness in this setting. Methods: A total of 185 mCRC pts were randomized to cetuximab (400mg/m² day 1, followed by 250mg/m² weekly) plus CAPIRI (irinotecan 200mg/m², day 1; capecitabine 800mg/m² twice daily days 1-14, every 3 weeks; 20% dose reduction of both agents for pts older than 65 years) or plus CAPOX (oxaliplatin 130mg/m² day 1; capecitabine 1000mg/m² twice daily days 1-14, every three weeks). The primary study endpoint was ORR. KRAS mutational status did not correlate with treatment outcome. The cut-offs for EGFR-amplification using FISH, AREG and EREG levels determined by RT-qPCR were calculated using ROC analysis for ORR. Results: Within the subgroup of KRAS wildtype tumors, analysis of EREG- and AREG-expression was possible in 99 pts and of EGFR-amplification in 63 pts. Higher AREG levels correlated significantly with higher ORR (83% vs 46%, p=0.006, OR 0.31), longer PFS (9.6mo vs 4.9, p<0.001, HR 0.35) and longer OS (39.9mo vs 17.2mo, p<0.001, HR 0.36). Higher EREG levels showed a significant correlation with ORR (74% vs 47%, p=0.036, OR 0.54), longer PFS (7.9mo vs 4.9mo, p=0.026, HR 0.57) and OS (33.0mo vs 20.2mo, p=0.041, HR 0.57). EGFR-amplification correlated significantly with higher ORR (71% vs 33%, p=0.004, OR 0.49), longer PFS (8.4mo vs 4.6mo, p=0.004, HR 0.50) and longer OS (30.5mo vs 15.2mo, p=0.001, HR 0.44). Conclusions: In the treatment setting of cetuximab combined with CAIPIRI or CAPOX, AREG, EREG and EGFR-amplification predicted treatment efficacy. Within the subgroup of pts with KRAS wildtype tumors, EGFR-FISH and AREG expression have the strongest relationship with treatment efficacy.

Cetuximab-related skin toxicity in metastatic colorectal cancer (mCRC) patients and its correlation with molecular markers: Results from the German AIO CRC 0104 trial

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Background: Skin toxicity is a frequent adverse event of EGFR targeting agents. The role of cetuximab induced skin toxicity (Cet-ST), for the most acneiform skin rash, as a prognostic or a predictive factor of treatment efficacy is currently under discussion.

Methods: The prognostic and predictive value of Cet-ST in relation to treatment response and survival of patients of a randomized trial investigating CAPIRI plus cetuximab versus CAPOX plus cetuximab as first-line treatment of mCRC was analyzed. Cet-ST was grouped into clinically relevant (grade 2-3) and non relevant (grade 0-1) toxicity (NCI-CTCAE 3.0). KRAS mutations in codons 12 and 13, EGFR-FISH, EGFR-IHC and EGFR intron-1 polymorphism were evaluated in tumor specimens.

Results: A total of 149 patients got cetuximab until the first tumor assessment (6 weeks) and were used for this analysis. Overall response rate was higher in patients with grade 2-3 Cet-ST when compared to grade 0-1 (62.1% vs. 41.3%). Patients without Cet-ST (grade 0) had a short PFS (1.9 months) and OS (11.0 months). PFS (7.8 months vs. 5.2 months) and OS (30.3 months vs. 18.0 months) were longer in patients with Cet-ST grade 2-3 than in patients with grade 0-1 Cet-ST. Almost 90% of Cet-ST occurred during the first two cycles of treatment. When only KRAS codon-12 mutated tumors which are thought not to be sensitive to cetuximab were investigated, Kaplan-Meier differences in PFS and OS times between patients with grade 0-1 Cet-ST and grade 2-3 Cet-ST became statistically significant. In a multivariate analysis, male gender, age and EGFR intron-1 polymorphism were significantly correlated with Cet-ST.

Conclusions: Cetuximab related skin toxicity is a strong predictor of outcome. It is proposed that Cet-ST is rather a prognostic than a predictive factor since this effect is most evident in patients with KRAS codon-12 mutated tumors. EGFR intron-1 polymorphism appears to be a predictor of Cet-ST.