Masamitsu Hihara

Importance: For patients with RAS wild-type metastatic colorectal cancer, adding anti-epidermal growth factor receptor (anti-EGFR) or anti-vascular endothelial growth factor (anti-VEGF) monoclonal antibodies to first-line doublet chemotherapy is routine, but the optimal targeted therapy has not been defined. Objective: To evaluate the effect of adding panitumumab (an anti-EGFR monoclonal antibody) vs bevacizumab (an anti-VEGF monoclonal antibody) to standard first-line chemotherapy for treatment of RAS wild-type, left-sided, metastatic colorectal cancer. Design, Setting, and Participants: Randomized, open-label, phase 3 clinical trial at 197 sites in Japan in May 2015-January 2022 among 823 patients with chemotherapy-naive RAS wild-type, unresectable metastatic colorectal cancer (final follow-up, January 14, 2022). Interventions: Panitumumab (n = 411) or bevacizumab (n = 412) plus modified fluorouracil, l-leucovorin, and oxaliplatin (mFOLFOX6) every 14 days. Main Outcomes and Measures: The primary end point, overall survival, was tested first in participants with left-sided tumors, then in the overall population. Secondary end points were progression-free survival, response rate, duration of response, and curative (defined as R0 status) resection rate. Results: In the as-treated population (n = 802; median age, 66 years; 282 [35.2%] women), 604 (75.3%) had left-sided tumors. Median follow-up was 61 months. Median overall survival was 37.9 months with panitumumab vs 34.3 months with bevacizumab in participants with left-sided tumors (hazard ratio [HR] for death, 0.82; 95.798% CI, 0.68-0.99; P = .03) and 36.2 vs 31.3 months, respectively, in the overall population (HR, 0.84; 95% CI, 0.72-0.98; P = .03). Median progression-free survival for panitumumab vs bevacizumab was 13.1 vs 11.9 months, respectively, for those with left-sided tumors (HR, 1.00; 95% CI, 0.83-1.20) and 12.2 vs 11.4 months overall (HR, 1.05; 95% CI, 0.90-1.24). Response rates with panitumumab vs bevacizumab were 80.2% vs 68.6%, respectively, for left-sided tumors (difference, 11.2%; 95% CI, 4.4%-17.9%) and 74.9% vs 67.3% overall (difference, 7.7%; 95% CI, 1.5%-13.8%). Median duration of response with panitumumab vs bevacizumab was 13.1 vs 11.2 months for left-sided tumors (HR, 0.86; 95% CI, 0.70-1.10) and 11.9 vs 10.7 months overall (HR, 0.89; 95% CI, 0.74-1.06). Curative resection rates with panitumumab vs bevacizumab were 18.3% vs 11.6% for left-sided tumors; (difference, 6.6%; 95% CI, 1.0%-12.3%) and 16.5% vs 10.9% overall (difference, 5.6%; 95% CI, 1.0%-10.3%). Common treatment-emergent adverse events were acneiform rash (panitumumab: 74.8%; bevacizumab: 3.2%), peripheral sensory neuropathy (panitumumab: 70.8%; bevacizumab: 73.7%), and stomatitis (panitumumab: 61.6%; bevacizumab: 40.5%). Conclusions and Relevance: Among patients with RAS wild-type metastatic colorectal cancer, adding panitumumab, compared with bevacizumab, to standard first-line chemotherapy significantly improved overall survival in those with left-sided tumors and in the overall population. Trial Registration: ClinicalTrials.gov Identifier: NCT02394795.

Certain genetic alterations and right-sided primary tumor location are associated with resistance to anti-epidermal growth factor (EGFR) treatment in metastatic colorectal cancer (mCRC). The phase 3 PARADIGM trial (n = 802) demonstrated longer overall survival with first-line anti-EGFR (panitumumab) versus antivascular endothelial growth factor (bevacizumab) plus modified FOLFOX6 in patients with RAS wild-type mCRC with left-sided primary tumors. This prespecified exploratory biomarker analysis of PARADIGM (n = 733) evaluated the association between circulating tumor DNA (ctDNA) gene alterations and efficacy outcomes, focusing on a broad panel of gene alterations associated with resistance to EGFR inhibition, including KRAS, NRAS, PTEN and extracellular domain EGFR mutations, HER2 and MET amplifications, and ALK, RET and NTRK1 fusions. Overall survival was prolonged with panitumumab plus modified FOLFOX6 versus bevacizumab plus modified FOLFOX6 in patients with ctDNA that lacked gene alterations in the panel (that is, negative hyperselected; median in the overall population: 40.7 versus 34.4 months; hazard ratio, 0.76; 95% confidence interval, 0.62-0.92) but was similar or inferior with panitumumab in patients with ctDNA that contained any gene alteration in the panel (19.2 versus 22.2 months; hazard ratio, 1.13; 95% confidence interval, 0.83-1.53), regardless of tumor sidedness. Negative hyperselection using ctDNA may guide optimal treatment selection in patients with mCRC. ClinicalTrials.gov registrations: NCT02394834 and NCT02394795 .

LBA1 Background: PARADIGM is the first prospective trial to test the superiority of PAN vs. BEV in combination with standard doublet first-line chemotherapy for patients (pts) with RAS WT mCRC and left-sided primary tumors. Methods: This open-label, multicenter trial in Japan (NCT02394795) randomly selected pts with chemotherapy-naive RAS WT mCRC to PAN + mFOLFOX6 or BEV + mFOLFOX6. Overall survival (OS) as primary endpoint was hierarchically tested in patients with left-sided tumors, followed by those in the full-analysis set (FAS) population. Key secondary endpoints included progression-free survival (PFS), response rate (RR), and curative resection (R0) rate. Results: From May 2015 to June 2017, 823 pts were randomized; 12 did not receive protocol treatment and 9 were excluded due to major deviation of inclusion criteria. A total of 400 pts received PAN and 402 pts received BEV as FAS; 312 and 292 pts had left-sided primary tumors, respectively. OS was analyzed after 448 OS events in left-sided pts with a median follow-up of 61 months. PAN significantly improved OS vs. BEV in both populations: left-sided (HR, 0.82; 95.798% CI, 0.68-0.99, p = .031, which crossed the boundary of significance [0.042]), and FAS (HR, 0.84; 95% CI, 0.72-0.98; p = .030, with < 0.05 as the boundary). Although PFS was comparable between treatment groups, RR and R0 resection rates were higher with PAN compared with BEV (Table). HR for OS in the right-sided population was 1.09. No new safety signal was observed. Conclusions: PAN significantly improved OS vs. BEV in combination with mFOLFOX6 in pts with RAS WT and left-sided mCRC, establishing a standard first-line combination regimen for this population. Clinical trial information: NCT02394795. [Table: see text]

BackgroundIt remains unclear whether an anti-VEGF or anti-EGFR antibody with standard doublet chemotherapy is the optimal first-line treatment in patients with RAS (KRAS/NRAS) wild-type metastatic colorectal cancer (mCRC). Here we outline the PARADIGM study (NCT02394795), designed to evaluate the superiority of panitumumab over bevacizumab, in combination with oxaliplatin/5-fluorouracil/leucovorin (mFOLFOX6) in patients with RAS wild-type chemotherapy-naïve mCRC.Patients and MethodsEligible patients are aged 20 to 79 years with an ECOG performance status of 0-1 and histologically/cytologically confirmed RAS wild-type mCRC. A total of 800 patients are to be randomly assigned (1:1 ratio) to mFOLFOX6 plus panitumumab (n = 400) or bevacizumab (n = 400) and stratified according to institution, age (20-64 vs. 65-79 years), and liver metastases (present vs. absent). Each treatment regimen includes oxaliplatin 85 mg/m2, l-leucovorin 200 mg/m2, and 5-fluorouracil (5-FU) I.V. 400 mg/m2 on day 1; 5-FU continuous I.V. 2400 mg/m2 on days 1 to 3; and either panitumumab 6 mg/kg or bevacizumab 5 mg/kg on day 1 every 2 weeks. The primary endpoint is overall survival forming the basis to detect a hazard ratio of 0.76 with a 1-sided type I error rate of 0.025 and 80% power. Secondary efficacy endpoints include progression-free survival, response rate, duration of response, and curative resection rate. A comprehensive biomarker analysis (NCT02394834) using archival tumor tissue and circulating tumor DNA samples collected at different time points (pretreatment and confirmed progressive disease) will investigate potential biomarkers related to primary and secondary resistance. The first patient was enrolled in May 2015 and the study is anticipated to complete in 2020.

85 Background: The optimal choice of monoclonal antibodies (mAbs) for first-line treatment in patients (pts) with RAS ( KRAS/NRAS) wild-type metastatic colorectal cancer (mCRC) remains controversial. The meta-analyses of subgroup analyses in phase III studies of pts with KRAS exon 2 wild-type mCRC suggested a longer overall survival (OS) with an anti-EGFR mAb over bevacizumab in pts with RAS wild-type mCRC or with left-sided primary tumors. However, there has been no prospective study comparing the two mAbs in these pt populations. This randomized phase III study was originally designed to demonstrate the superiority of panitumumab versus bevacizumab, both in combination with mFOLFOX6, for RAS wild-type mCRC, but we have revised the protocol to analyze efficacy in pts with a left-sided primary tumor as the primary (final) analysis. Methods: Eligible pts are aged 20-79 years with histologically/cytologically confirmed RAS wild-type chemotherapy-naive mCRC, and ECOG performance status 0-1. Between May 29, 2015 and Jun 8, 2017, 823 pts were randomized 1:1 to panitumumab plus mFOLFOX6 or bevacizumab plus mFOLFOX6 by the minimization method and the randomisation was stratified by institution, age (20-64 vs. 65-79 years), and liver metastases (present vs. absent). The primary analysis was revised to adopt a hierarchical testing procedure; we first compare OS between the two arms in left-sided primary tumor population, and only if there is statistically significant difference, then ITT population analysis will be performed. In this revised plan, the expected number of deaths is 420 in the left-sided population to provide 80% power to detect an OS hazard ratio of 0.74 at a one-sided significance level of 0.02101 determined on the alpha spending function approach after one interim analysis. A large-scale exploratory biomarker substudy to identify potential biomarker candidates using tumor tissue and circulating tumor DNA is also underway (Clinical trial no.: NCT02394834). The data cut off for the primary analysis is expected to be during 1Q 2021. Results: Results are expected in 2021. Conclusions: Results are expected in 2021. Clinical trial information: NCT0239475.