Epidermal growth factor receptor (EGFR) inhibitors are valuable therapeutics in metastatic colorectal cancer (mCRC). Anti-EGFR monoclonal antibodies (MoAbs), such as cetuximab or panitumumab, in ...combination with chemotherapy are effective treatment options for patients with RAS and BRAF wild-type mCRC. Nevertheless, several issues are still open concerning the optimal use of anti-EGFR drugs in the continuum of care of mCRC. Novel approaches for increasing the efficacy of anti-EGFR therapies include better molecular selection of EGFR-dependent mCRC, intensification of chemotherapy, combination of anti-EGFR MoAbs and immune checkpoint inhibitors, and reintroduction of EGFR blockade or ‘rechallenge’ in selected patients who have previously responded to anti-EGFR MoAb therapy. An extensive translational research program was conducted in the Cetuximab After Progression in KRAS wIld-type colorectal cancer patients-Gruppo Oncologico dell' Italia Meridionale (CAPRI-GOIM) study with the aims of determining which subgroups of patients could benefit from the continuous inhibition of EGFR, from evaluating the role of liquid biopsy-based and its concordance with tissue-based molecular testing, and from investigating novel potential mechanisms of resistance to anti-EGFR therapies. In this review, we summarize the translational and clinical findings of the CAPRI-GOIM program in the context of the current knowledge of therapeutic strategies and of ongoing research on more appropriate uses of anti-EGFR therapies in RAS and BRAF wild-type mCRC patients.
•The epidermal growth factor (EGFR) is a therapeutic option for patients with all RAS WT metastatic colorectal cancer (mCRC).•A better knowledge of the mechanism of primary or acquired resistance to EGFR-therapies can improve patient's selection.•Despite disease progression a subset of mCRC are still sensitive to EGFR inhibition.•Rechallenge strategies with anti-EGFR might represent a promising therapeutic option.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Evidence suggests that metastatic colorectal carcinoma (mCRC) has a high level of intratumor heterogeneity. We carried out a quantitative assessment of tumor heterogeneity for KRAS, NRAS, BRAF and ...PIK3CA mutations, in order to assess potential clinical implications.
Tumor samples (n = 182) from the CAPRI-GOIM trial of first-line cetuximab + FOLFIRI in KRAS exon-2 wild-type mCRC patients were assessed by next-generation sequencing that allows quantitative assessment of mutant genes. Mutant allelic frequency was normalized for the neoplastic cell content and, assuming that somatic mutations usually affect one allele, the Heterogeneity Score (HS) was calculated by multiplying by 2 the frequency of mutant alleles in neoplastic cells. Therefore, HS virtually corresponds to the fraction of neoplastic cells carrying a specific mutation.
The KRAS HS ranged between 12 and 260 with mean value of 87.1 and median value of 84.4, suggesting that in most CRC, the majority of neoplastic cells carry mutant KRAS. Similar findings were observed for NRAS (HS range 35.5–146.7; mean 102.8; median 117.1). In contrast, in BRAF (HS range 17.1–120; mean 54.8; median 54.3) and PIK3CA (HS range 14.3–120; mean 59.5; median 47.3) mutant cases, only a fraction of neoplastic cells seem to carry the mutant allele. The response rate was 70% in KRAS mutant patients with an HS <33 (low KRAS; n = 10) and 45.7% in KRAS HS >33 patients (high KRAS; n = 35); median progression-free survival were 7.97 and 8.37 months, respectively. Low-KRAS tumors had a higher frequency of additional mutations in PIK3CA when compared with high-KRAS (6/10 versus 8/35).
KRAS and NRAS mutations are usually present in the majority of neoplastic cells, whereas BRAF and PIK3CA mutations often affect a limited fraction of transformed cells. Resistance to cetuximab in low-KRAS patients might be driven by the complex mutational profile rather than KRAS mutation load.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Treatment with antiepidermal growth factor receptor (anti-EGFR) monoclonal antibodies has been restricted to metastatic colorectal cancer (mCRC) patients with RAS wild-type tumors. Next-generation ...sequencing (NGS) allows the assessment in a single analysis of a large number of gene alterations and might provide important predictive and prognostic information.
In the CAPRI-GOIM trial, 340 KRAS exon 2 wild-type mCRC patients received first-line FOLFIRI plus cetuximab. Tumor samples (182/340, 53.5%) were assessed by NGS to search for mutations in 22 genes involved in colon cancer.
Objective responses in the NGS cohort were observed in 104/182 patients overall response rate (ORR) 57.1%; 95% confidence interval (95% CI) 52% to 66.4% with a median progression-free survival (mPFS) of 9.8 (95% CI 8.7–11.5) months. NGS analysis was successfully completed in all 182 samples. One or more gene mutations (up to five) were detected in 124/182 (68.1%) tumors within 14/22 genes for a total of 206 mutations. KRAS exon 2 mutations were identified in 29/182 (15.9%) samples, defined as wild type by local laboratory assessment. Frequently mutated genes were: TP53 (39.6%), KRAS exons 3/4 (8.8%), NRAS exons 2/3 (7.1%), PIK3CA exons 9/20 (13.2%), BRAF (8.2%). FOLFIRI plus cetuximab treatment determined ORR of 62.0% (95% CI 55.5% to 74.6%) with mPFS of 11.1 (95% CI 9.2–12.8) months in patients with KRAS and NRAS wild-type tumors. Conversely, ORR was 46.6% (95% CI 39.9–57.5%) with mPFS of 8.9 (95% CI 7.4–9.6) months in patients with KRAS or NRAS mutations. Similarly, the subgroup of patients carrying KRAS, NRAS, BRAF, or PIK3CA mutations showed a worse outcome, although this might be due to a prognostic effect.
This study demonstrates that NGS analysis in mCRC is feasible, reveals high level of intra and intertumor heterogeneity, and identifies patients that might benefit of FOLFIRI plus cetuximab treatment.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Scientific data provide the evidence that secondary K-RAS mutations do not occur during anti-epidermal growth factor receptor therapy in colorectal cancer patients. This multicenter phase II ...prospective study aims to investigate the activity of a retreatment with a cetuximab-based therapy.
We enrolled 39 irinotecan-refractory patients who had a clinical benefit after a line of cetuximab- plus irinotecan-based therapy and then a progression of disease for which underwent a new line chemotherapy and finally, after a clear new progression of disease, were retreated with the same cetuximab- plus irinotecan-based therapy.
Median number of therapeutic lines before accrual was 4. Median interval time between last cycle of first cetuximab-based therapy and first cycle of the retreatment was 6 months. Overall response rate was 53.8% with 19 partial responses (48.7%) and 2 complete responses (5.1%). Disease stabilization was obtained in 35.9% of patients and progression in four patients (10.2%). Median progression-free survival was 6.6 months. The correlation between skin toxicity during first cetuximab therapy and during cetuximab rechallenge was significant (P=0.01).
Rechallenge with the same cetuximab-based therapy may achieve a new important clinical benefit further delaying the progression of disease and improving the therapeutic options.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Liquid biopsy is an alternative to tissue for RAS testing in metastatic colorectal carcinoma (mCRC) patients. Little information is available on the predictive role of liquid biopsy RAS testing in ...patients treated with first-line anti-EGFR monoclonal antibody-based therapy.
In the CAPRI-GOIM trial, 340 KRAS exon-2 wild-type mCRC patients received first-line cetuximab plus FOLFIRI. Tumor samples were retrospectively assessed by next generation sequencing (NGS). Baseline plasma samples were analyzed for KRAS and NRAS mutations using beads, emulsion, amplification, and magnetics digital PCR (BEAMing). Discordant cases were solved by droplet digital PCR (ddPCR) or deep-sequencing.
A subgroup of 92 patients with available both NGS data on tumor samples and baseline plasma samples were included in this study. Both NGS analysis of tumor tissue and plasma testing with BEAMing identified RAS mutations in 33/92 patients (35.9%). However, 10 cases were RAS tissue mutant and plasma wild-type, and additional 10 cases were tissue wild-type and plasma mutant, resulting in a concordance rate of 78.3%. Analysis of plasma samples with ddPCR detected RAS mutations in 2/10 tissue mutant, plasma wild-type patients. In contrast, in all tissue wild-type and plasma mutant cases, ddPCR or deep-sequencing analysis of tumor tissue confirmed the presence of RAS mutations at allelic frequencies ranging between 0.15% and 1.15%. The median progression-free survival of RAS mutant and wild-type patients according to tissue (7.9 versus 12.6 months; P = 0.004) and liquid biopsy testing (7.8 versus 13.8 moths; P < 0.001) were comparable. Similar findings were observed for the median overall survival of RAS mutant and wild-type patients based on tissue (22.1 versus 35.8 months; P = 0.016) and plasma (19.9 versus 35.8 months; P = 0.013) analysis.
This study indicates that RAS testing of liquid biopsy results in a similar outcome when compared with tissue testing in mCRC patients receiving first-line anti-EGFR monoclonal antibodies.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Data are limited regarding bone metastases from colorectal cancer (CRC). The objective of this study was to survey the natural history of bone metastasis in CRC.
This retrospective, multicenter, ...observational study of 264 patients with CRC involving bone examined cancer treatments, bone metastases characteristics, skeletal-related event (SRE) type and frequency, zoledronic acid therapy, and disease outcomes.
Most patients with bone metastases had pathologic T3/4 disease at CRC diagnosis. The spine was the most common site involved (65%), followed by hip/pelvis (34%), long bones (26%), and other sites (17%). Median time from CRC diagnosis to bone metastases was 11.00 months; median time to first SRE thereafter was 2.00 months. Radiation and pathologic fractures affected 45% and 10% of patients, respectively; 32% of patients had no reported SREs. Patients survived for a median of 7.00 months after bone metastases diagnosis; SREs did not significantly affect survival. Subgroup analyses revealed that zoledronic acid significantly prolonged median time to first SRE (2.00 months versus 1.00 month, respectively, P = 0.009) and produced a trend toward improved overall survival versus no zoledronic acid.
This study illustrates the burden of bone metastases from CRC and supports the use of zoledronic acid in this setting.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Cetuximab plus chemotherapy is a first-line treatment option in metastatic KRAS and NRAS wild-type colorectal cancer (CRC) patients. No data are currently available on continuing anti-epidermal ...growth factor receptor (EGFR) therapy beyond progression.
We did this open-label, 1:1 randomized phase II trial at 25 hospitals in Italy to evaluate the efficacy of cetuximab plus 5-fluorouracil, folinic acid and oxaliplatin (FOLFOX) as second-line treatment of KRAS exon 2 wild-type metastatic CRC patients treated in first line with 5-fluorouracil, folinic acid and irinotecan (FOLFIRI) plus cetuximab. Patients received FOLFOX plus cetuximab (arm A) or FOLFOX (arm B). Primary end point was progression-free survival (PFS). Tumour tissues were assessed by next-generation sequencing (NGS). This report is the final analysis.
Between 1 February 2010 and 28 September 2014, 153 patients were randomized (74 in arm A and 79 in arm B). Median PFS was 6.4 95% confidence interval (CI) 4.7–8.0 versus 4.5 months (95% CI 3.3–5.7); hazard ratio (HR), 0.81; 95% CI 0.58–1.12; P = 0.19, respectively. NGS was performed in 117/153 (76.5%) cases; 66/117 patients (34 in arm A and 32 in arm B) had KRAS, NRAS, BRAF and PIK3CA wild-type tumours. For these patients, PFS was longer in the FOLFOX plus cetuximab arm median 6.9 (95% CI 5.5–8.2) versus 5.3 months (95% CI 3.7–6.9); HR, 0.56 (95% CI 0.33–0.94); P = 0.025. There was a trend in better overall survival: median 23.7 (95% CI 19.4–28.0) versus 19.8 months (95% CI 14.9–24.7); HR, 0.57 (95% CI 0.32–1.02); P = 0.056.
Continuing cetuximab treatment in combination with chemotherapy is of potential therapeutic efficacy in molecularly selected patients and should be validated in randomized phase III trials.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Oxaliplatin-based adjuvant chemotherapy is the standard treatment of high-risk colon cancer (CC). A shorter duration (3 months) can achieve a similar outcome in terms of relapse-free survival (RFS) ...to a longer duration. This study reports the overall survival (OS) analysis of the three or six colon adjuvant (TOSCA) phase III study. It assessed different adjuvant chemotherapy durations in patients with resected high-risk stage II and stage III CC.
TOSCA was an open-label, phase III, multicentre, non-inferiority trial conducted in 130 Italian centres. Patients were randomly assigned, in a 1 : 1 ratio, to receive 3 months of standard doses of FOLFOX/CAPOX, or 6 months of FOLFOX/CAPOX. Patients with histologically confirmed high-risk stage II and III CC were included, with RFS being the primary end point. OS was a secondary end point.
From June 2007 to March 2013, 3759 patients were accrued. At a median follow-up of 7 years, the hazard ratio (HR) for RFS of the 3-month versus 6-month arms was 1.13; 95% confidence interval (CI) 0.99-1.29, P for non-inferiority = 0.380, P for superiority = 0.068, crossing the non-inferiority limit of 1.20. This result did not allow us to reject the null hypothesis of the inferiority of the 3-month arm. The HR for OS of the 3-month versus 6-month arms was 1.09 (95% CI 0.93-1.26, P for superiority = 0.288). At the last follow-up analysis, the absolute OS difference between arms was <1%.
The present analysis of the TOSCA trial does not indicate any significant difference in OS between the treatment groups. The extra benefit provided by the longer treatment should be balanced against the extra toxicity of more prolonged therapy. The trial is registered with ClinicalTrials.gov, registration number: NCT0064660.
•TOSCA trial compared 3 or 6 months of adjuvant chemotherapy.•We here provided the updated results of OS at 7 years of median follow up.•The HR for OS of the 3-month versus 6-month arms was 1.09 (95% CI 0.93-1.26, P for superiority = 0.288).•At the last follow-up analysis, the absolute OS difference between arms was <1%.•The present analysis of the TOSCA trial does not indicate any significant difference in OS between the treatment groups.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The rechallenge strategy is based on the concept that a subset of patients with RAS wild‐type (WT) metastatic colorectal cancer (mCRC) could still benefit of epidermal growth factor receptor (EGFR) ...inhibition, after progression to an anti‐EGFR based‐therapy. We performed a pooled analysis of two‐phase II prospective trials to determine the role of rechallenge in third‐line mCRC patients with RAS/BRAF WT baseline circulating tumor DNA (ctDNA). Individual data of 33 and 13 patients from CAVE and CRICKET trials that received as third‐line therapy cetuximab rechallenge were collected. Overall survival (OS), Progression‐free survival (PFS), Overall response rate (ORR), Stable disease (SD) >6 months were calculated. Adverse events were reported. For the whole 46 patient population, median PFS (mPFS) was 3.9 months (95% Confidence Interval, CI 3.0–4.9) with median OS (mOS) of 16.9 months (95% CI 11.7–22.1). For CRICKET patients, mPFS was 3.9 months (95% CI 1.7–6.2); mOS was 13.1 months (95% CI 7.3–18.9) with OS rates at 12, 18, and 24 months of 62%, 23%, and 0%, respectively. For CAVE patients, mPFS was 4.1 months (95% CI 3.0–5.2); mOS was 18.6 months (95% CI 11.7–25.4) with OS rates at 12, 18, 24 months of 61%, 52%, 21%, respectively. Skin rash was more frequently reported in CAVE trial (87.9% vs. 30.8%; p = 0.001), whereas a increased incidence of hematological toxicities was observed in CRICKET trial (53.8%% vs. 12.1%; p = 0.003). Third‐line cetuximab rechallenge in combination with either irinotecan or avelumab in RAS/BRAF WT ctDNA mCRC patients represents a promising therapy.
Liquid biopsy guides anti‐EGFR rechallenge therapy in CRICKET and CAVE trails.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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