Wild-type Metastatic Colorectal Cancer Research Articles

Size-related heterogeneity of colorectal liver metastases (CRLM) in patients with advanced RAS wild-type metastatic colorectal cancer (mCRC) treated in the PanaMa trial: Implication for treatment decisions.

3553 Background: In patients with mCRC, the liver represents the primary site of metastasis. In patients with primarily unresectable metastatic disease, primary tumor location and molecular subtypes mainly determine the therapeutic approach. In addition, image-based characterization of hepatic metastatic pattern may provide additional information concerning prognosis and treatment efficacy. Therefore, CRLM were characterized according to size-based heterogeneity in the PanaMa trial (maintenance therapy with 5-fluoruracil/leucovorin (FU/FA) plus panitumumab (Pmab) vs. FU/FA alone following induction therapy with six cycles of FU/FA, oxaliplatin and Pmab). Methods: Assessments were performed in patients with at least two lesions, considering target and non-target lesions, within a central radiological review of the trial. Variance in size expressed as ratio between the smallest and largest lesion measured (≤/ > threefold difference in size) was evaluated for its prognostic and predictive impact on progression-free (PFS) and overall (OS) survival of maintenance therapy. Time-to-event endpoints were expressed by Kaplan-Meier method and compared by log-rank tests. Cox regressions were used to indicate Hazard ratios (HR) with 95% CIs. Results: Imaging data of 211/248 (85.1%) patients receiving maintenance therapy were evaluable for central radiological review (FU/FA+ Pmab, n = 106; FU/FA, n = 105). Of those, 165/211 patients (78.2%) had at least two CRLM. Size of CRLM ranged between 5–180mm, with the smallest metastasis in the individual assessments measuring a median of 12mm and the largest a median of 53mm. Large heterogeneity with more than a threefold difference in size between the smallest and largest CRLM was observed in 49.7% of patients, particularly pronounced in patients with polymetastatic disease ( > 5 lesions). Homogeneous metastasis in terms of lesion size (≤ threefold difference) was associated with favorable OS (HR 0.63; 95% CI, 0.42–0.95; P = 0.027) - irrespective of study arm- compared to heterogeneous lesion disease. Maintenance therapy with FU/FA+ Pmab compared with FU/FA alone seemed favourably active in both patients with heterogeneous metastases (HR 0.53; 95% CI; 0.34–0.85; P = 0.008) as well as to a numerically lesser extent in patients with homogeneous metastases (HR 0.68; 95% CI, 0.43–1.10; P= 0.116). Conclusions: Imaging-based characterization of CRLM focusing on size-related heterogeneity was associated with favorable prognosis potentially indicating more aggressive underlying tumor dynamics in case of heterogeneous lesion size. In addition, the efficacy of Pmab during maintenance was evident in both patient groups (homogeneous and heterogeneous disease lesions) with a numerically greater effect in patients with heterogeneous lesions. Clinical trial information: NCT01991873 .

P-87 A multi-institutional observational study evaluating the efficacy of anti-epidermal growth factor antibody re-challenge in tissue RAS/BRAF wild-type metastatic colorectal cancer

P-87 A multi-institutional observational study evaluating the efficacy of anti-epidermal growth factor antibody re-challenge in tissue RAS/BRAF wild-type metastatic colorectal cancer

A phase Ⅰ/Ⅱa study of cetuximab combined with fruquintinib in the previously treated RAS/BRAF wild-type metastatic colorectal cancer: Results of the CEFRU study.

e15558 Background: The standard third-line treatment for mCRC is regorafenib, fruquintinib or TAS-102. However, the efficacy was not satisfied. Since VEGF and EGFR share the downstream signaling pathway, targeting these two pathways may have synergistic efficacy. The phase Ib trial with regorafenib combined with cetuximab have shown preliminary benefit. Fruquintinib is a small molecule highly selective VEGFR1/2/3 molecule inhibitor. Here, we evaluate the safety and efficacy of fruquintinib plus cetuximab in previously treated RAS/BRAF wild-type mCRC. Methods: This is an open-label phase I/IIa study. The primary objective was to determine the recommended phase 2 dose (RP2D) in a 3+3 dose escalation strategy in phase I and safety, grade 3/4 adverse events in phase IIa. Secondary objectives include ORR, mPFS, and mOS. Eligible patients were diagnosed as advanced RAS/BRAF wild-type CRC and had received at least two prior regimens of standard therapies. Exclude patients who have previously used other small molecule anti-vascular inhibitors. The planned number of cases is 20(including phaseⅠandⅡa). ChiCTR2000038227. Results: Between Sep, 2020 to Sep, 2022, 21 pts were enrolled including 7 patients of phase Ⅰ. The RP2D is fruquintinib 4 mg QD (3 weeks on/1 week off) plus cetuximab 500mg/m2 every two weeks, received by 17 pts. Two patient dropped out，one because of refusing treatment and another due to severe allergic reaction. 15 pts were included in the efficacy analysis and 16 pts in the safety analysis. The left side mCRC accounted for 87.5%. 68.8% have received cetuximab and 75% have received bevacizumab. The overall TRAE was 75.0%, with 25.0% grade 3 or above. The most common treatment-related AEs were acneiform rash, hypoproteinemia and dry skin (Table1). One patient had dose reduction of fruquintinib due to acneiform rash. Evaluation in 15 treated patients showed 2 cases were PR, 10 were SD and 3 were PD. DCR was 80%. mPFS was 128 days(95%CI:49.7-206.3). mOS was 229 days(95%CI: 104.0-354.0). Conclusions: Cetuximab combined with fruquintinib showed promising anti-tumor activity in CRC with resistance to at least two prior regimens. The toxicity was tolerable and no unexpected toxicities were observed (Table 1). Clinical trial information: Clinical trial information: ChiCTR2000038227 . [Table: see text]

SO-26 Intermittent or continuous panitumumab plus FOLFIRI for first-line treatment of patients with RAS/BRAF wild-type metastatic colorectal cancer: An update of survival/toxicity and preliminary results of genomic alterations from IMPROVE study

SO-26 Intermittent or continuous panitumumab plus FOLFIRI for first-line treatment of patients with RAS/BRAF wild-type metastatic colorectal cancer: An update of survival/toxicity and preliminary results of genomic alterations from IMPROVE study

Early tumor shrinkage (ETS) as clinical factor to select maintenance with cetuximab (cet) monotherapy in patients (pts) with RAS/BRAF wild-type (wt) metastatic colorectal cancer (mCRC): A secondary endpoint analysis of the ERMES study.

3603 Background: ERMES study aimed to demonstrate non-inferior PFS of maintenance with cetuximab (cet) monotherapy (arm B) compared to FOLFIRI+cet until progression (arm A) in RAS and BRAF wt mCRC pts. Although study did not meet its primary endpoint it showed better toxicity profile and OS for cet alone and comparable ORR between arms. Here we present results of ETS, a secondary endpoint. Methods: ETS was defined as ≥20% reduction of the sum of target lesions at 8 weeks from the start of treatment, and was assessed by blinded independent central review. PFS and OS were compared between ETS+ and ETS- pts according to treatment arm in the modified Per-Protocol (mPP) population. Results: 327 of 337 (97%) pts were evaluable for ETS. In arm A, no statistically significant differences were observed between ETS+ and ETS- cohort for PFS (11.9 m, 95%CI 11.28-13.19, vs 12.2 m, 95%CI 10.82-14.93; HR 1.05, 95%CI 0.73-1.50; p 0.77) and OS (30.75 m, 95%CI 25.09-37.73, vs 25.46 m, 95%CI 19.96-34.63; HR: 0.79, 95%CI 0.50-1.24; p 0.29). In arm B, a statistically significant difference was observed between ETS+ and ETS- cohort for PFS (10.62 m, 95%CI 9.86-13.09, vs 8.52 m, 95%CI 7.89-9.37; HR 0.70, 95%CI 0.49-1.00; p 0.036) and for OS (38.88 m, 95%CI 34.53-43.25, vs27.43 m, 95%CI 20.59-36.64; HR 0.60, 95%CI 0.38-0.93; p 0.019). ETS+ pts reported no statistically significant difference between arm B and arm A in terms of PFS (HR 1.12, 95%CI 0.83-1.49; p 0.43) while experiencing a better OS for arm B compared to arm A (HR 0.72, 95%CI 0.50-1.05; p 0,08). Conclusions: In pts achieving ETS, induction treatment with FOLFIRI+cet may be de-escalated to cet alone without detrimental effect on PFS, resulting in less toxicity and better OS. These data support the hypothesis that ETS might be a clinical dynamic predictor of efficacy of a less intensive maintenance strategy, allowing to plan de-escalation to cet alone after 4 months of FOLFIRI+cet induction. Clinical trial information: NCT02484833 .

Serial ctDNA monitoring to predict response in mCRC patients treated with anlotinib in combination with oxaliplatin and capecitabine (CAPEOX) as the first-line therapy.

e15581 Background: Circulating tumour DNA (ctDNA) sequencing offers a non-invasive approach to monitor therapeutic efficacy in colorectal cancer. However, the mutational landscape of ctDNA during treatment and its impact on clinical outcomes remain unknown. This study aimed to investigate the value of ctDNA in predicting treatment response and PFS in mCRC patients treated with anlotinib plus CAPEOX as first-line therapy. Methods: We conducted a multicenter, single-arm, phase II, exploratory study of patients with RAS/BRAF wild-type unresectable metastatic colorectal cancer (mCRC) who underwent Anlotinib in combination with CAPEOX as the first-line therapy (NCT04080843). Plasma samples from 26 patients were collected at three timepoints: 1 week before treatment (baseline), close to the time of optimal remission (C1) and the time of the last blood collection or the time of disease progression (C2). The maximum somatic allele frequency (MSAF) was calculated for each case and used to provide an estimate of the ctDNA fraction in the blood. Results: 77 plasma samples from the 26 enrolled mCRC patients were sequenced by NGS based on a panel comprising 202 genes. 90 variations were detected in baseline plasma, with a positive rate of 96.2% (25/26). Adenomatous polyposis coli ( APC), was the most mutated gene (84.6%, 22/26). Other mutated genes were TP53 (80.8%, 21/26), FBXW7 (19.2%, 5/26), KRAS (11.5%, 3/26), PIK3CA (11.5%, 3/26) and ROS1 (11.5%, 3/26). The median MSAF of baseline ctDNA was significantly higher in patients who had only liver metastases. Compared with baseline, the ctDNA MSAF level at C1 timepoint was decreased among the whole 26 patients (p < 0.001). By comparing ctDNA positive group (ctDNA MSAF > 0) and ctDNA negative group (ctDNA MSAF = 0) at C1 timepoint, CR cases were mainly in ctDNA negative group, while PD cases accounted for a high proportion in the ctDNA positive group. The median progression-free survival (mPFS) of the whole patients was 11.27 months (95%CI 7.33m to 14.52m). The mPFS was 14.52 months (95% CI 14.4 to NR) of patients with ctDNA negative at C1, which was longer than 9.17 months (95% CI 7.16 to 14.06) of patients with ctDNA positive at C1 (p = 0.012). For 25 patients who had plasma samples of three timepoints, we divided the patients into Non-PD group and PD group according to the clinical outcome at C2 timepoint. Compared with C1 timepoint, the ctDNA MSAF level at C2 timepoint was increased in both Non-PD group and PD group. However, the increment of ctDNA MSAF level in PD group was higher than that in non-PD group (p = 0.000069 vs p = 0.024). Conclusions: This ctDNA profiling study revealed the utility of ctDNA in predicting clinical outcomes in mCRC patients under first-line treatment. Serial ctDNA monitoring might become useful in an active surveillance strategy for the management of mCRC. Clinical trial information: NCT04080843 .

SO-27 Modified FOLFOXIRI plus cetuximab and avelumab as initial therapy in RAS wild-type unresectable metastatic colorectal cancer: Results of the phase II AVETRIC trial by GONO

SO-27 Modified FOLFOXIRI plus cetuximab and avelumab as initial therapy in RAS wild-type unresectable metastatic colorectal cancer: Results of the phase II AVETRIC trial by GONO

Intermittent or continuous panitumumab plus FOLFIRI (FOLFIRI/PANI) for first-line treatment of patients (pts) with RAS/BRAF wild-type (wt) metastatic colorectal cancer (mCRC): An update of survival/toxicity and preliminary results of genomic alterations from IMPROVE study.

3571 Background: IMPROVE is a randomized, non-comparative multicenter, phase 2 study which evaluated continuous, until progressive disease (PD), or intermittent FOLFIRI/PANI, in pts with unresectable and previously untreated RAS/BRAF wt mCRC. In the intermittent schedule 8 cycles were followed by a treatment free interval lasting until PD when another 8 cycles were restarted, continuing this strategy until PD occurred on treatment. Primary endpoints was progression-free survival on treatment (PFSOT) at 1 year. In a previous analysis the primary endpoint of the study was met and a reduced skin toxicity was observed in the intermittent arm. Here we report an updated analysis. Methods: Updated analysis includes PFSOT and toxicity with 9 months (mo) of additional follow-up. Moreover we report overall survival (OS), skin toxicity burden (STB) score and preliminary data on genomic alterations (GAs) in 46 pts with PD. STB score, incorporating both the frequency and the severity of skin toxicity, was obtained by summing all grades that the pts experienced across all treatment cycles. GAs were performed by NGS on circulating tumor DNA (ctDNA) from paired plasma samples (baseline and progression), focusing specifically on RAS, BRAF and PI3K mutations. Results: Pts received FOLFIRI/PANI continuously (arm A, 69 pts) or intermittently (arm B, 67 pts). Median number of FOLFIRI/PANI cycles administered per pt were (arm A/B) 13/16. In arm B, after induction treatment, 24/53 pts (45%) without PD had ≥ 2 rounds of 8 FOLFIRI/PANI cycles. ORR (arm A/B) was 63/57%. At a median follow-up of 28 mo (IQR: 21-37), median PFSOT (77% of events) was 11.4 mo (95% CI: 9.1-13.7) in arm A, and 18.1 mo (95% CI: 6.8-29.3) in arm B. Median PFSOT in left sided tumors was 11.7 mo (95% CI: 9.1-14.3) in arm A and 23.9 mo (95% CI: 15.0-32.9) in arm B, compared with 10.7 mo (95% CI: 7.3-14.1) and 7.9 mo (95% CI: 5.7-10.1) in right sided pts, respectively. OS (46% of events) was 31.0 mo (95% CI: 24.7-37.2) in arm A and 32.2 mo (95% CI: 23.6-40.8) in arm B. Main grade ≥ 3 toxicities were (arm A/B): skin 30/18%, neutropenia 25/24%; diarrhea 13/15%. Median STB score was 0.77/cycle (IQR: 0.20-1.06) in arm A and 0.36/cycle (IQR: 0-0.77) in arm B. GAs in baseline ctDNA were evidenced in 12/46 (26%) pts, persisting to PD in all but one pt. Among the 34 pts without baseline GAs, only 8 (23%) developed ≥ 1 acquired GAs (Acq-GAs) to PD. Conclusions: Updated analyses confirmed that intermittent FOLFIRI/PANI strategy produces a long PFSOT and a reduced skin severe and skin burden toxicity without any detrimental effect on OS. Preliminary data on Acq-GAs suggest that classical mutations associated with anti-EGFR resistance are infrequent with up-front use of anti-EGFR/chemotherapy. Clinical trial information: NCT04425239 .

Negative selection of patients (pts) with HER2-positive and RAS wild-type (wt) metastatic colorectal cancer (mCRC) receiving dual HER2 blockade.

e15164 Background: Refining the selection of pts with HER2-positive mCRC for dual HER2 blockade is a challenge for precision oncology. Alterations in receptor tyrosin-kinase (RTK)/MAPK pathway and HER2 gene copy number (GCN) are promising predictive biomarkers for primary resistance or sensitivity, respectively. Methods: We conducted a multicentric case-control study to evaluate the negative predictive impact of a panel of candidate genomic alterations of primary resistance (PRESSING-HER panel) in pts with HER2-positive, RAS wt mCRC treated with trastuzumab-based dual HER2 blockade. Comprehensive genomic profiling was performed on archival pre-treatment tumor samples and screening sources were: the TRIUMPH trial (Oncomine Comprehensive Assay), the Italian-Spanish observational cohort (Foundation One CDx) and the MSKCC cohort (MSK-IMPACT). The panel grouped resistance alterations with a solid biological rationale as on-target, i.e. HER2 pathogenic mutations or rearrangements or off-target, i.e. mutations/amplifications in RTK/MAPK genes. Primary resistance was defined by PFS < 4 months (mos), sensitivity was defined by PFS ≥4 mos. Hypothesizing a prevalence of PRESSING-HER alterations equal to 5% and 30% among controls and cases, respectively, 35 cases and 35 controls were needed to reject the null hypothesis of equally prevalent alterations, with α and β errors of 0.05 and 0.20. HER2 GCN was derived from NGS and the cut-off was calculated by ROC curve analyses using 4-month PFS rate as endpoint. Results: Sixty-eight pts were evaluable (33 resistant and 35 sensitive). In the overall population, PRESSING-HER alterations were found in 14 (20.6%) pts and included HER2 mutations in 7 (50%), HER2 rearrangements in 4 (29%), BRAF class 1 mutations in 2 (14%) and EGFR amplification in 1 (7%). PRESSING-HER alterations were significantly more frequent in pts with primary resistant (12/21, 57%) versus (vs) sensitive tumors (2/35, 6%; P= 0.004). HER2 GCN had a median value of 34.5 (IQR: 18.7-78.5) and an optimal cut-off of 33. In multivariable analyses including the main baseline clinical prognostic features, PRESSING-HER alterations were independently associated with inferior PFS (median PFS 2.0 vs 5.4 mos; adjusted HR 3.5, 95%CI 1.7-7.0; P< 0.001) and OS (median OS 3.7 vs 14.8 mos; adjusted HR 3.9, 95%CI 1.8-8.3; P< 0.001). HER2 GCN < 33 was associated with significantly inferior median PFS (2.6 vs 5.4 mos; adjusted HR 1.8, 95%CI 1.0-3.1; P= 0.038) and numerically inferior OS (median OS 9.1 vs 15.4 mos; adjusted HR 1.3, 95%CI 0.7-2.5; P= 0.356). The predictive accuracy of PRESSING-HER was 66% and it was increased to 77% when combined with HER2 GCN. Conclusions: The combined assessment of HER2 on/off-target alterations and HER2 GCN stratifies patient outcomes to HER2 dual blockade.

The multi-omics signature to predict sensitive to anti-epidermal growth factor receptor therapy in RAS wild-type colorectal cancer liver metastases.

e15578 Background: There are nearly half patients with Ras wild-type metastatic colorectal cancer (mCRC) do not response to Anti-EGFR therapy. Identification of patients who are sensitive to anti-EGFR therapy may increase the response rate and reduce the adverse effect. In this study, we aimed to develop and validate a multi-omics deep learning model to predict cetuximab efficacy in RAS wild type mCRC patients. Methods: In this study, we retrospectively analyzed 213 Ras wild type mCRC patients. The training and testing cohorts comprised patients in Arm A (FOLFOX + cetuximab) of the CHINESE study (NCT01564810) and patients in the CHINESE follow-up study (PMID: 30305811). The external and negative validation cohorts were derived from an independent cohort and Arm B (FOLFOX) of the CHINESE study, respectively. Based on the deep learning framework Pytorch, we first built the radiomic and genetic signature. Next, we passed the CT images and gene data into the trained ResNet18 and Random Forest and then we sum the output probabilities of two models with a weight of 3:7 to obtain the classification probability of the fusion model. Results: The signature successfully predict sensitivity to anti-EGFR therapy (The area under the curve (AUC) of the radiomic signature: 0.75; the genetic signature: 0.81; the fusion signature: 0.86) but failed with chemotherapy (The fusion signature: 0.54). In cetuximab-containing sets, the fusion signature outperformed existing biomarkers for detection of treatment sensitivity (OR = 17.9, 95% CI 3.22–154.31, P = 0.003) and was strongly associated with progression free survival (mPFS: 12.0 vs. 15.0 months, HR: 0.44, 95% CI 0.20–0.99, P = 0.047). Conclusions: The multi-omics signature can serve as an intermediate surrogate marker of anti-EGFR treatment sensitivity and survival. The signature outperformed known biomarkers in providing an early prediction of treatment sensitivity and could be used to RAS wild type mCRC treatment decisions.

SO-24 Panitumumab plus trifluridine/tipiracil as anti-EGFR rechallenge therapy in patients with refractory RAS wild-type metastatic colorectal cancer: Overall survival and subgroup analysis of the randomized phase 2 VELO trial

SO-24 Panitumumab plus trifluridine/tipiracil as anti-EGFR rechallenge therapy in patients with refractory RAS wild-type metastatic colorectal cancer: Overall survival and subgroup analysis of the randomized phase 2 VELO trial

Impact of number and size of colorectal metastases (CRM) on survival in patients with RAS wild-type metastatic colorectal cancer treated within the PanaMa trial (AIO KRK 0212).

3551 Background: In this exploratory analysis, we aim to evaluate surrogates of metastatic burden, namely number of CRMs and size of largest CRM, for their prognostic and predictive value on efficacy of maintenance therapy with 5-fluorouracil/leucovorin (FU/FA) plus panitumumab (pmab) or FU/FA alone in RAS wildtype mCRC patients treated within the PanaMa trial. Methods: Number of CRMs and size of largest CRM at baseline were determined taking into account target and non-target lesions measured by central radiological review. Median number of metastases was set as threshold (n≤/ > 10) to assess the prognostic and predictive value of CRM count on PFS and OS of maintenance therapy. A threshold of ≤/ > 50mm was set to evaluate the impact of the largest CRM on the above time-to-event endpoints. PFS and OS were expressed by Kaplan-Meier method and compared by log-rank testing. Hazard ratios (HR) with 95% CIs were estimated using Cox regression models. Results: Out of 248 patients receiving maintenance therapy, CT and MRI scans of 211 patients were centrally evaluable (FU/FA+ Pmab, n = 106; FU/FA alone, n = 105). At baseline, 50.1% of the patients were diagnosed with > 10 CRM. Median size of the largest CRM was 45 mm. Number of CRMs n≤10 was associated with favorable PFS, while both, number n≤10, and size of largest CRM ≤50mm correlated with favorable OS compared to n > 10 and size of largest CRM > 50mm, respectively. In patients with > 10 CRMs, and those with largest CRM sized > 50mm, PFS of maintenance therapy was significantly superior with FU/FA+ Pmab compared to FU/FA alone (Table). Conclusions: Metastatic burden was found to be prognostic for PFS and OS of maintenance therapy. Additionally, number and largest size of CRMs proofed predictive of PFS of maintenance therapy with Pmab, the primary endpoint of the trial. Patients with high metastatic burden at baseline appear to benefit particularly from Pmab-containing maintenance therapy. Clinical trial information: NCT01991873 . [Table: see text]

SO-25 Modified (m)-FOLFOXIRI plus cetuximab versus m-FOLFOXIRI plus bevacizumab as initial treatment for RAS and BRAF wild-type metastatic colorectal cancer: Updated survival analysis of the DEEPER trial by JACCRO

SO-25 Modified (m)-FOLFOXIRI plus cetuximab versus m-FOLFOXIRI plus bevacizumab as initial treatment for RAS and BRAF wild-type metastatic colorectal cancer: Updated survival analysis of the DEEPER trial by JACCRO

Differential Efficacy of Targeted Monoclonal Antibodies in Left-Sided Colon and Rectal Metastatic Cancers

BackgroundThe recommended first-line chemotherapy for RAS/BRAF wild-type metastatic colorectal cancer (mCRC) is bevacizumab (BEV)-containing therapy for right-sided colon cancer (R) and antiepidermal growth factor receptor antibody (anti-EGFR)-containing therapy for left-sided colon cancer (L) or rectal cancer (RE). However, anatomical or biological heterogeneity reportedly exists between L and RE. Therefore, we aimed to compare the efficacies of anti-EGFR and BEV therapies for L and RE, respectively. MethodsWe retrospectively reviewed 265 patients with KRAS (RAS)/BRAF wild-type mCRC treated with fluoropyrimidine-based doublet chemotherapy plus anti-EGFR or BEV as the first-line treatment at a single institution. They were divided into 3 groups: R, L, and RE. Overall survival (OS), progression-free survival (PFS), objective response rate, and conversion surgery rate were analyzed. ResultsForty-five patients had R (anti-EGFR/BEV: 6/39), 137 patients had L (45/92), and 83 patients had RE (25/58). In patients with R, both median (m) PFS and OS were superior with BEV therapy (mPFS, anti-EGFR vs. BEV: 8.7 vs. 13.0 months, hazard ratio [HR]: 3.90, P = .01; mOS, 17.1 vs. 33.9 months, HR: 1.54, P = .38). In patients with L, better mPFS and comparable mOS with anti-EGFR therapy were observed (mPFS, 20.0 vs. 13.4 months, HR: 0.68, P = .08; mOS, 44.8 vs. 36.0 months, HR: 0.87, P = .53), whereas, in patients with RE, comparable mPFS and worse mOS with anti-EGFR therapy were observed (mPFS, 17.2 vs. 17.8 months, HR: 1.08, P = .81; mOS, 29.1 vs. 42.2 months, HR: 1.53, P = .17). ConclusionsEfficacies of anti-EGFR and BEV therapies may differ between patients with L and RE.

China special issue on gastrointestinal tumors-Cetuximab retreatment plus camrelizumab and liposomal irinotecan in patients with RAS wild-type metastatic colorectal cancer: Cohort B of the phase II CRACK study.

Patients with metastatic colorectal cancer (mCRC) have poor long-term survival. Rechallenge with anti-epidermal growth factor receptor (anti-EGFR) based therapy has shown certain activity as late-line therapy. To further improve clinical outcomes, we evaluated the antitumor efficacy and safety of cetuximab in combination with camrelizumab and liposomal irinotecan in patients with RASwt mCRC pretreated with anti-EGFR-based therapy. Patients with RASwt mCRC who had received at least two prior systemic therapies, including anti-EGFR-based treatment in the metastatic or unresectable disease setting, were enrolled in cohort B. Patients were treated with cetuximab (500 mg/m2 ) and camrelizumab (200 mg) plus liposomal irinotecan (HR070803, 60 mg/m2 ) intravenously once every 2 weeks. The primary endpoint was the objective response rate (ORR) by RECIST v1.1. The secondary endpoints included disease control rate (DCR), progression-free survival (PFS), overall survival (OS) and safety. At the data cutoff (23 November 2022), 19 patients were enrolled in the two stages, and 16 were evaluable for efficacy analyses. The ORR was 25% (95% confidence interval [CI]: 10.2%-49.5%), and DCR was 75% (95% CI: 50.5%-89.8%). The median PFS and OS were 6.9 (95% CI: 2.6-11.2) and 15.1 (95% CI: 6.1-24.0) months, respectively. Grade 3 treatment-related adverse events (TRAEs) occurred in 15.8% (3/19) of patients. No grade ≥4 TRAEs were found in the safety population. Our study suggests that anti-EGFR retreatment therapy with cetuximab plus camrelizumab and liposomal irinotecan (HR070803) is a promising late-line treatment option with good antitumor activity and well-tolerated toxicity in RASwt mCRC patients.

Tucatinib plus trastuzumab for chemotherapy-refractory, HER2-positive, RAS wild-type unresectable or metastatic colorectal cancer (MOUNTAINEER): a multicentre, open-label, phase 2 study

HER2 is an actionable target in metastatic colorectal cancer. We assessed the activity of tucatinib plus trastuzumab in patients with chemotherapy-refractory, HER2-positive, RAS wild-type unresectable or metastatic colorectal cancer. MOUNTAINEER is a global, open-label, phase 2 study that enrolled patients aged 18 years and older with chemotherapy-refractory, HER2-positive, RAS wild-type unresectable or metastatic colorectal cancer at 34 sites (clinics and hospitals) in five countries (Belgium, France, Italy, Spain, and the USA). Initially, the study was designed as a single-cohort study, which was expanded following an interim analysis to include more patients. Initially, patients were given tucatinib (300 mg orally twice daily) plus intravenous trastuzumab (8 mg/kg as an initial loading dose, then 6 mg/kg every 21 days; cohort A) for the duration of treatment (until progression), and after expansion, patients were randomly assigned (4:3), using an interactive web response system and stratified by primary tumour location, to either tucatinib plus trastuzumab (cohort B) or tucatinib monotherapy (cohort C). The primary endpoint was confirmed objective response rate per blinded independent central review (BICR) for cohorts A and B combined and was assessed in patients in the full analysis set (ie, patients with HER2-positive disease who received at least one dose of study treatment). Safety was assessed in all patients who received at least one dose of study treatment. This trial is registered with ClinicalTrials.gov, NCT03043313, and is ongoing. Between Aug 8, 2017, and Sept 22, 2021, 117 patients were enrolled (45 in cohort A, 41 in cohort B, and 31 in cohort C), of whom 114 patients had locally assessed HER2-positive disease and received treatment (45 in cohort A, 39 in cohort B, and 30 in cohort C; full analysis set), and 116 patients received at least one dose of study treatment (45 in cohort A, 41 in cohort B, and 30 in cohort C; safety population). In the full analysis set, median age was 56·0 years (IQR 47-64), 66 (58%) were male, 48 (42%) were female, 88 (77%) were White, and six (5%) were Black or African American. As of data cutoff (March 28, 2022), in 84 patients from cohorts A and B in the full analysis set, the confirmed objective response rate per BICR was 38·1% (95% CI 27·7-49·3; three patients had a complete response and 29 had a partial response). In cohorts A and B, the most common adverse event was diarrhoea (55 [64%] of 86), the most common grade 3 or worse adverse event was hypertension (six [7%] of 86), and three (3%) patients had tucatinib-related serious adverse events (acute kidney injury, colitis, and fatigue). In cohort C, the most common adverse event was diarrhoea (ten [33%] of 30), the most common grade 3 or worse adverse events were increased alanine aminotransferase and aspartate aminotransferase (both two [7%]), and one (3%) patient had a tucatinib-related serious adverse event (overdose). No deaths were attributed to adverse events. All deaths in treated patients were due to disease progression. Tucatinib plus trastuzumab had clinically meaningful anti-tumour activity and favourable tolerability. This treatment is the first US Food and Drug Administration-approved anti-HER2 regimen for metastatic colorectal cancer and is an important new treatment option for chemotherapy-refractory HER2-positive metastatic colorectal cancer. Seagen and Merck & Co.

Panitumumab vs Bevacizumab Added to Standard First-line Chemotherapy and Overall Survival Among Patients With RAS Wild-type, Left-Sided Metastatic Colorectal Cancer

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. 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. 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). Panitumumab (n = 411) or bevacizumab (n = 412) plus modified fluorouracil, l-leucovorin, and oxaliplatin (mFOLFOX6) every 14 days. 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. 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%). 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. ClinicalTrials.gov Identifier: NCT02394795.

Consensus Molecular Subtypes as Biomarkers of Fluorouracil and Folinic Acid Maintenance Therapy With or Without Panitumumab in RAS Wild-Type Metastatic Colorectal Cancer (PanaMa, AIO KRK 0212).

Consensus molecular subtypes (CMSs) were evaluated as prognostic and predictive biomarkers of patients with RAS wild-type metastatic colorectal cancer (mCRC) receiving fluorouracil and folinic acid (FU/FA) with or without panitumumab (Pmab) after Pmab + mFOLFOX6 induction within the randomized phase II PanaMa trial. CMSs were determined in the safety set (ie, patients that received induction) and full analysis set (FAS; ie, randomly assigned patients who received maintenance) and correlated with median progression-free survival (PFS) and overall survival (OS) since the start of induction or maintenance treatment and objective response rates (ORRs). Hazard ratios (HRs) and 95% CI were calculated by univariate/multivariate Cox regression analyses. Of 377 patients of the safety set, 296 (78.5%) had available CMS data: CMS1/2/3/4: 29 (9.8%)/122 (41.2%)/33 (11.2%)/112 (37.8%) and unclassifiable: 17 (5.7%). The CMSs were prognostic biomarkers in terms of PFS (P < .0001), OS (P < .0001), and ORR (P = .02) since the start of induction treatment. In FAS patients (n = 196), with CMS2/4 tumors, the addition of Pmab to FU/FA maintenance therapy was associated with longer PFS (CMS2: HR, 0.58 [95% CI, 0.36 to 0.95], P = .03; CMS4: HR, 0.63 [95% CI, 0.38 to 1.03], P = .07) and OS (CMS2: HR, 0.88 [95% CI, 0.52 to 1.52], P = .66; CMS4: HR, 0.54 [95% CI, 0.30 to 0.96], P = .04). The CMS interacted significantly with treatment in terms of PFS (CMS2 v CMS1/3: P = .02; CMS4 v CMS1/3: P = .03) and OS (CMS2 v CMS1/3: P = .03; CMS4 v CMS1/3: P < .001). The CMS had a prognostic impact on PFS, OS, and ORR in RAS wild-type mCRC. In PanaMa, Pmab + FU/FA maintenance was associated with beneficial outcomes in CMS2/4, whereas no benefit was observed in CMS1/3 tumors.

Impact of primary tumor side on clinical outcomes of first-line cetuximab plus FOLFOX-4 in RAS wild-type metastatic colorectal cancer.

Aim: To examine the impact of tumor sidedness on clinical outcomes in Chinese patients with metastatic colorectal cancer treated with folinic acid/fluorouracil/oxaliplatin (FOLFOX-4)±cetuximab in the TAILOR trial. Patients & methods: Clinical data from 391 patients were evaluated for tumor sidedness. Results: Patients with left-sided tumors who received cetuximab plus FOLFOX-4 had a significantly longer overall survival (medians: 22.0 vs 18.3months; p=0.007) and progression-free survival (medians: 9.3 vs 7.9months; p=0.006) compared with FOLFOX-4 alone. Overall survival (medians: 11.5 vs 9.4months; p=0.664) and progression-free survival (medians: 7.4 vs 4.5months; p=0.068) also improved in patients with right-sided tumors. Conclusion: Adding cetuximab to first-line FOLFOX-4 in patients with metastatic colorectal cancer improved clinical outcomes irrespective of primary tumor side.

Pretreatment Plasma Circulating Tumor DNA RAS/BRAF Mutational Status in Refractory Metastatic Colorectal Cancer Patients Who Are Candidates for Anti-EGFR Rechallenge Therapy: A Pooled Analysis of the CAVE and VELO Clinical Trials.

Rechallenge with anti-EGFR drugs represents a promising strategy in refractory RAS/BRAF wild-type (WT) metastatic colorectal cancer (mCRC). We performed the pooled analysis of the CAVE and VELO studies to evaluate the percentage of patients with WT circulating tumor DNA (ctDNA) tumors and the association of mutational status with time from the last anti-EGFR drug administration. At baseline, 97/129 patients had RAS/BRAF WT plasma ctDNA, while 32/129 had RAS/BRAF mutated plasma ctDNA. Median anti-EGFR drug-free interval was 10.6 (CI 95%, 8.9-13.4) months in the plasma RAS/BRAF mutant group as compared to 13.0 (CI 95%, 11.1-16.6) months in RAS/BRAF WT group (p = 0.169). To investigate the time window of the RAS/BRAF mutant cancer cell clone disappearance, descriptive analysis using different time points was performed. No difference in the proportion of patients whose baseline plasma ctDNA was RAS/BRAF WT or mutated was found between 4 and 18 months since the last administration of anti-EGFR drugs. In contrast, 38/44 of patients with anti-EGFR drug-free interval of 18 months or more displayed a ctDNA RAS/BRAF WT status. Taken together, these results shows that the length of anti-EGFR free interval is not a sufficient criterion for patient selection, supporting the role of liquid biopsies for improving treatment efficacy.