Published OnlineFirst January 31, 2012; DOI: 10.1158/1078-0432.CCR-11-1135 Clinical Cancer Predictive Biomarkers and Personalized Medicine Research Correlation between Gene Expression of IGF-1R Pathway Markers and Cetuximab Benefit in Metastatic Colorectal Cancer Fei Huang, Li-an Xu, and Shirin Khambata-Ford Abstract Purpose: This study examined potential correlations between markers related to the insulin-like growth factor-1 receptor (IGF-1R) pathway and clinical benefit from the anti–epidermal growth factor receptor (EGFR) monoclonal antibody cetuximab in metastatic colorectal cancer (mCRC). Experimental Design: Gene expression profiles for 70 pretreatment specimens from metastatic lesions of patients with chemorefractory mCRC receiving cetuximab monotherapy were analyzed using 74 predefined Gene-Chip probesets representing 33 unique IGF-1R pathway markers to determine correlations with progression-free survival (PFS) and disease control rate. Results: Higher IGF-1R, higher GRB7, and lower INSIG2 expression were associated with longer PFS with cetuximab in univariate analyses, particularly in patients with wild-type K-Ras tumors: median, 122 versus 60 days (P ¼ 0.01), 122 versus 57 days (P ¼ 0.011), and 57 versus 156 days (P < 0.0001), favoring higher IGF- 1R, higher GRB7, and lower INSIG2 expression, respectively. Lower IGF-1 expression was associated with a PFS benefit with cetuximab, whereas lower IGFBP3 and INSR expression levels showed trends for a PFS benefit. Lower INSIG2 expression (vs. higher expression) was associated with greater PFS in the high epiregulin-expressing group (P ¼ 0.001), but not in the low-expressing cohort suggesting an effect independent from the previously reported effect of epiregulin expression. Lower INSIG2 expression was also associated with higher disease control rate in the overall population (51.4% vs. 11.4%; P ¼ 0.001) and wild-type K-Ras subset (76.2% vs. 18.2%; P < 0.0001). Conclusions: These results suggest that markers of the IGF-1R pathway may play a role in predicting benefit from cetuximab therapy in mCRC. Additional clinical studies are warranted to validate these findings. Clin Cancer Res; 18(4); 1156–66. Ó2012 AACR. Introduction that the presence of K-Ras exon-2 mutations (codons 12 and 13) predicts lack of cetuximab benefit in mCRC, both as Cetuximab is an anti–epidermal growth factor receptor single-agent therapy in patients who are refractory to che- (EGFR) monoclonal antibody that has antitumor efficacy in motherapy and in combination with chemotherapy in metastatic colorectal cancer (mCRC; refs. 1, 2); locoregion- treatment-na€ve patients (2, 6–8). Whereas these original ally advanced recurrent or metastatic squamous cell carci- studies bundled all known exon-2 mutations as one single noma of the head and neck (3, 4); and advanced non–small "resistance genotype," more recent studies have indicated cell lung cancer (NSCLC; ref. 5). In unselected patients with that patients with tumors carrying the G13D mutation may mCRC, cetuximab significantly improved survival as a sin- benefit from therapy, suggesting that this mutation may not gle agent compared with best supportive care in patients have the same effect as the rest on exon-2 (9, 10). These previously treated with fluoropyrimidine, irinotecan, and findings represent a significant breakthrough in mCRC oxaliplatin (1), and when added to first-line FOLFIRI com- treatment because they allow cetuximab to be directed to pared with FOLFIRI alone (6). Multiple studies have shown patients who are most likely to benefit. However, not all patients with wild-type K-Ras benefit from cetuximab-based therapy, and further refinement of patient selection is Authors' Affiliation: Bristol-Myers Squibb Co., Princeton, New Jersey desirable. Note: Supplementary data for this article are available at Clinical Cancer In chemotherapy (particularly irinotecan)-refractory Research Online (http://clincancerres.aacrjournals.org/). patients, there is a growing list of candidate predictive Corresponding Author: Fei Huang, Bristol-Myers Squibb Co., Route 206 markers under investigation. These include EGFR gene copy and Province Line Rd., Room E1.293, Princeton, NJ 08453. Phone: 609- number measured by FISH, ligand gene expression (amphir- 252-4891; Fax: 1-609-818-5839; E-mail: [email protected] egulin and epiregulin [EREG]) or polymorphisms (EGF), doi: 10.1158/1078-0432.CCR-11-1135 mutations in components of the MAP-Ras-Raf pathway, Ó2012 American Association for Cancer Research. loss of the PTEN gene, and PIK3CA expression levels or 1156 Clin Cancer Res; 18(4) February 15, 2012 Downloaded from clincancerres.aacrjournals.org on October 1, 2021. © 2012 American Association for Cancer Research. Published OnlineFirst January 31, 2012; DOI: 10.1158/1078-0432.CCR-11-1135 IGF-1R Pathway Markers and Cetuximab Benefit in CRC activated protein kinase (MAPK) and phosphoinositide Translational Relevance 3-kinase (PI3K), and may work collaterally to drive tumor growth and survival (reviewed in ref. 30). The IGF-1R Patients with metastatic colorectal cancer (mCRC) pathway appears to regulate EGFR signaling and, recipro- whose tumors harbor the wild-type K-Ras gene may cally, EGFR ligands may promote tumor survival through derive benefit from treatment with the anti–epidermal IGF-1R (31–33). Indeed, overexpression of the EGFR ligand growth factor receptor (EGFR) monoclonal antibody amphiregulin in NSCLC cell lines stimulates IGF-1R, lead- cetuximab, whereas those patients with tumors bearing ing to IGF-1 and amphiregulin secretion and inhibition of certain K-Ras mutations do not benefit. However, not all apoptosis (32). EGFR tyrosine kinase inhibitors (TKI) can patients with wild-type K-Ras tumors benefit from cetux- induce EGFR/IGF-1R heterodimerization and alter the imab, underscoring the need for additional markers to interactions between IGF-1R and insulin receptor (INSR) help in patient selection. Preclinical evidence suggests substrate (IRS)-1 in cancer cells, activating downstream that the EGFR and insulin-like growth factor-1 receptor signaling and resulting in resistance to further TKI treatment (IGF-1R) pathways interact to drive tumor growth and (34–36). Conversely, coinhibition of both pathways results survival. This study evaluated whether expression levels in synergistic antitumor effects in several preclinical cancer of the IGF-1R pathway markers correlate with cetuximab models (36–41). benefit in patients with chemorefractory mCRC, includ- Therefore, it is reasonable to hypothesize that molecular ing the subset of patients with wild-type K-Ras. The markers associated with the IGF-1R pathway may affect the results provide initial evidence that markers of the antitumor activity of EGFR inhibitors. In this study, we IGF-1R pathway may predict benefit from cetuximab analyzed the gene expression levels of IGF-1R pathway therapy in mCRC, but this preliminary finding requires components previously identified as potential points of validation in additional clinical studies. EGFR-IGF-1R cross-talk (15) and investigated their poten- tial correlation with cetuximab benefit in patients with chemorefractory mCRC, both in the overall population and in the group with K-Ras wild-type tumors. mutations. All have been reported to affect the clinical activity of cetuximab (11–25), mostly in relatively small Methods patient cohorts, often without randomized controls. Com- bining the testing for K-Ras mutation with one or more of Patients and study design these markers could further enhance patient selection and The CA225-045 trial was a phase II pharmacogenomic the overall therapeutic index of cetuximab in mCRC. The study in which 110 patients with chemorefractory mCRC advantages of this approach have been illustrated by the received single-agent cetuximab after failing at least one enrichment in responding patients achieved with nested chemotherapeutic regimen for advanced disease or refusing mutational screening of tumors for K-Ras, B-Raf, N-Ras, prior treatment. Details of the study design and patient PIK3CA (26), or with the combimarker of K-Ras mutation cohort have been described previously (13). Patients plus EREG expression (16). received cetuximab at its standard dose (400 mg/m2 loading In previously untreated patients with mCRC receiving dose; then 250 mg/m2 weekly) for 3 weeks and then were first-line therapy, however, data from randomized con- eligible for dose-escalation every 3 weeks to a maximum of trolled studies are lacking for most of the candidate predic- 400 mg/m2 weekly, provided they had not experienced tive markers for anti-EGFR therapy. One in particular, B-Raf greater than grade II skin rashes. Tumor responses were V600E mutation, has not upheld the potentially predictive evaluated every 9 weeks according to modified WHO cri- value consistently reported in noncontrolled retrospective teria (42). The disease control rate (DCR) was defined as the series of irinotecan-refractory patients (23, 25, 26), showing proportion of patients with a complete response (CR), instead a notable prognostic effect in controlled studies partial response (PR), or stable disease (SD). Progression- of untreated patients, regardless of cetuximab treatment free survival (PFS) was defined as the time from enrollment (6, 27). The data are therefore conflicting and preclude firm until disease progression or death. The study protocol was practical recommendations for any predictive marker other approved by the Institutional Review Board at each partic- than K-Ras exon-2 mutations. Whether the apparent