Survival impact of sequential chemotherapy following pembrolizumab for recurrent or metastatic head and neck squamous cell carcinoma

BACKGROUND

Pembrolizumab alone or combined with chemotherapy is the standard of care for first-line treatment of patients with recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC) with positive programmed death-ligand 1 combined positive scores. However, data on second-line chemotherapy following pembrolizumab are scarce.

METHODS

A single-center, retrospective study was conducted to determine the efficacies of pembrolizumab and pembrolizumab plus chemotherapy as first-line treatments and the efficacy of second-line chemotherapy for patients with R/M HNSCC who were refractory or intolerant to first-line treatment.

RESULTS

Fifty-four patients were treated with pembrolizumab, and 29 received second-line therapy, with 27 opting for cetuximab-containing regimens. The median progression-free survival (PFS), overall survival (OS), and PFS on next-line therapy for first-line treatment were 4.7 (95% confidence interval [CI], 2.1-8.7), 22.1 (95% CI, 12.6-not reached), and 15.6 months (95% CI, 9.7-not reached) in the pembrolizumab group and 5.4 (95% CI, 3.3-6.8), 15.8 (95% CI, 8.6-not reached), and 13.7 months (95% CI, 8.1-not reached) in the pembrolizumab plus chemotherapy group, respectively. The overall response rate and median PFS for second-line treatment were 48.3% (95% CI, 30.4-67.0) and 6.1 months (95% CI, 2.30-8.84). The median OS for patients who received second-line treatment was 18.4 months, which was superior to the median OS of 6.0 months for patients who received the best supportive care (log-rank p = 0.10).

CONCLUSION

This study indicates that cetuximab-containing second-line chemotherapy can improve outcomes in R/M HNSCC, even after first-line therapy failure or intolerance.

Safety and Efficacy of Gemcitabine Plus Cisplatin Against Recurrent/Metastatic Nasopharyngeal Carcinoma: A Retrospective Study

BACKGROUND/AIM

Although gemcitabine plus cisplatin (GC) prolongs survival in patients with recurrent or metastatic nasopharyngeal carcinoma (R/M NPC) compared with fluorouracil plus cisplatin, no study has evaluated the efficacy and safety of GC in nonendemic regions, including Japan, yet. Therefore, we assessed the safety and efficacy of GC in Japanese patients with R/M NPC.

PATIENTS AND METHODS

We retrospectively reviewed patients with R/M NPC who received GC treatment at the Aichi Cancer Center Hospital from January 2017 to March 2020. The main eligibility criteria were histologically confirmed NPC, Eastern Cooperative Oncology Group performance status (ECOG PS) of 0-2, and locally recurrent disease unsuitable for local treatment or metastatic disease. The regimen was administered every 3 weeks (gemcitabine, 1,000 mg/m2 on days 1 and 8; cisplatin, 80 mg/m2 on day 1).

RESULTS

Fourteen patients (median age, 58 years) were included in the study. Two patients had an ECOG PS of 2 and 11 exhibited nonkeratinizing histology. Of the eight patients with measurable lesions, one exhibited complete response and seven exhibited partial response, with an objective response rate of 75%. Median progression-free survival and overall survival were 7.7 and 24.2 months, respectively. Common grade 3 or 4 adverse events included neutropenia (64%), thrombocytopenia (14%), and febrile neutropenia (14%). The median relative dose intensity of gemcitabine and cisplatin was 62% and 60%, respectively. No treatment-related deaths occurred.

CONCLUSION

The GC regimen demonstrates promising activity and is tolerable in Japanese patients with R/M NPC.

Plasma Angiogenic Factors as Predictors of the Efficacy of Second-line Chemotherapy Combined with Angiogenesis Inhibitors in Metastatic Colorectal Cancer: Results From the GI-SCREEN CRC-Ukit Study

BACKGROUND

The significance of angiogenic factors as predictors of second-line (2L) chemotherapy efficacy when combined with angiogenesis inhibitors for metastatic colorectal cancer (mCRC) remains unestablished.

PATIENTS AND METHODS

In this multicenter prospective observational study, 17 angiogenic factors were analyzed in plasma samples collected at pretreatment and progression stages using a Luminex multiplex assay. Patients who received chemotherapy plus bevacizumab (BEV group), FOLFIRI plus ramucirumab (RAM group), or FOLFIRI plus aflibercept (AFL group) as the 2L treatment were included. Interactions between pretreatment and treatment groups for progression-free survival (PFS), overall survival (OS), and response rate (RR) were assessed using the propensity-score weighted Cox proportional hazards model.

RESULTS

From February 2018 to September 2020, 283 patients were analyzed in the 2L cohort. A strong interaction was observed for PFS between BEV and RAM with HGF, sNeuropilin-1, sVEGFR-1, and sVEGFR-3. Interactions for RR between the BEV and RAM groups were observed for sNeuropilin-1 and sVEGFR-1. Contrarily, OS, PlGF, sVEGFR-1, and sVEGFR-3 differentiated the treatment effect between BEV and AFL. Plasma samples were evaluable for dynamic analysis in 203 patients. At progression, VEGF-A levels significantly decreased in the BEV group and increased in the RAM and AFL groups.

CONCLUSION

The pretreatment plasma sVEGFR-1 and sVEGFR-3 levels could be predictive biomarkers for distinguishing BEV and RAM when combined with chemotherapy in 2L mCRC treatment. Based on the VEGF-A dynamics at progression, selecting RAM or AFL for patients with significantly elevated VEGF-A levels may be a 2L treatment strategy, with BEV considered for the third-line treatment.

CLINICAL TRIAL NUMBER

UMIN000028616.

Exploratory Biomarker Analysis Using Plasma Angiogenesis-Related Factors and Cell-Free DNA in the TRUSTY Study: A Randomized, Phase II/III Study of Trifluridine/Tipiracil Plus Bevacizumab as Second-Line Treatment for Metastatic Colorectal Cancer

BACKGROUND

The TRUSTY study evaluated the efficacy of second-line trifluridine/tipiracil (FTD/TPI) plus bevacizumab in metastatic colorectal cancer (mCRC).

OBJECTIVE

This exploratory biomarker analysis of TRUSTY investigated the relationship between baseline plasma concentrations of angiogenesis-related factors and cell-free DNA (cfDNA), and the efficacy of FTD/TPI plus bevacizumab in patients with mCRC.

PATIENTS AND METHODS

The disease control rate (DCR) and progression-free survival (PFS) were compared between baseline plasma samples of patients with high and low plasma concentrations (based on the median value) of angiogenesis-related factors. Correlations between cfDNA concentrations and PFS were assessed.

RESULTS

Baseline characteristics (n = 65) were as follows: male/female, 35/30; median age, 64 (range 25-84) years; and RAS status wild-type/mutant, 29/36. Patients in the hepatocyte growth factor (HGF)-low and interleukin (IL)-8-low groups had a significantly higher DCR (risk ratio [95% confidence intervals {CIs}]) than patients in the HGF-high (1.83 [1.12-2.98]) and IL-8-high (1.70 [1.02-2.82]) groups. PFS (hazard ratio {HR} [95% CI]) was significantly longer in patients in the HGF-low (0.33 [0.14-0.79]), IL-8-low (0.31 [0.14-0.70]), IL-6-low (0.19 [0.07-0.50]), osteopontin-low (0.39 [0.17-0.88]), thrombospondin-2-low (0.42 [0.18-0.98]), and tissue inhibitor of metalloproteinase-1-low (0.26 [0.10-0.67]) groups versus those having corresponding high plasma concentrations of these angiogenesis-related factors. No correlation was observed between cfDNA concentration and PFS.

CONCLUSION

Low baseline plasma concentrations of HGF and IL-8 may predict better DCR and PFS in patients with mCRC receiving FTD/TPI plus bevacizumab, however further studies are warranted.

CLINICAL TRIAL REGISTRATION NUMBER

jRCTs031180122.

Bevacizumab, Irinotecan, and Biweekly Trifluridine/Tipiracil for Metastatic Colorectal Cancer: MODURATE, a Phase Ib Study

BACKGROUND

In this phase Ib study MODURATE, we optimized the dosing schedule and tested the efficacy and safety of trifluridine/tipiracil, irinotecan, and bevacizumab in patients with metastatic colorectal cancer with fluoropyrimidine and oxaliplatin treatment failure.

METHODS

We included a dose escalation (3 + 3 design) and an expansion cohort. Patients were administered trifluridine/tipiracil (25-35 mg/m2 twice daily, days 1-5), irinotecan (150-180 mg/m2, day 1), and bevacizumab (5 mg/kg, day 1) every 2 weeks. The recommended phase II dose (RP2D) in the dose escalation cohort was administered to at least 15 patients in both cohorts combined.

RESULTS

Twenty-eight patients were enrolled. Five dose-limiting toxicities were observed. RP2D was defined as trifluridine/tipiracil 35 mg/m2, irinotecan 150 mg/m2, and bevacizumab 5 mg/kg. Of 16 patients who received RP2D, 86% (14/16) experienced grade ≥3 neutropenia without febrile neutropenia. Dose reduction, delay, and discontinuation occurred in 94%, 94%, and 6% of patients, respectively. Three patients (19%) showed partial response and 5 had stable disease for >4 months, with a median progression-free and overall survival of 7.1 and 21.7 months, respectively.

CONCLUSION

Biweekly trifluridine/tipiracil, irinotecan, and bevacizumab administration may have moderate antitumor activity with high risk of severe myelotoxicity in previously treated patients with metastatic colorectal cancer [UMIN Clinical Trials Registry (UMIN000019828) and Japan Registry of Clinical Trials (jRCTs041180028)].

Identification of an optimal mutant allele frequency to detect activating KRAS, NRAS, and BRAF mutations in a commercial cell-free DNA next-generation sequencing assay in colorectal and pancreatic adenocarcinomas

Background

Evaluation for activating mutations in KRAS, NRAS, and BRAF in colorectal cancer (CRC) and in KRAS in pancreatic ductal adenocarcinoma (PDAC) is essential for clinical care. Plasma cell-free DNA (cfDNA) next-generation sequencing (NGS) allows convenient assessment of a tumor's molecular profile, however low tumor DNA shedding limits sensitivity. We investigated mutant allele frequency (MAF) of other oncogenic dominant genes to identify a threshold for accurate detection of KRAS, NRAS, and BRAF (RAS/RAF) mutations in cfDNA.

Methods

Molecular and clinical data were obtained from the Duke Molecular Registry of Tumors and the SCRUM-Japan GOZILA study. Patients with CRC or PDAC and a KRAS, NRAS, or BRAF activating single nucleotide variant (SNV) present on tissue NGS and with available cfDNA assays were included. Recursive partitioning and Wilcoxon-rank statistics methods identified potential cut-points for discriminative MAF values.

Results

One hundred and thirty-five CRC and 30 PDAC cases with 198 total cfDNA assays met criteria. Greatest non-RAS/RAF dominant gene MAF of 0.34% provided maximum discrimination for predicting RAS/RAF SNV detection. Sensitivity for RAS/RAF SNVs increased with dominant gene MAF, with MAF ≥1% predicting sensitivity >98%, MAF between 0.34 and 1% predicting sensitivity of 84.0%, and MAF £0.34% predicting sensitivity of 50%. For 43 cfDNA assays that did not detect RAS/RAF SNVs, 18 assays detected 34 other oncogenic variants, of which 80.6% were not also detected on tissue.

Conclusions

Non-RAS/RAF dominant oncogenic mutation MAF ≥1% on cfDNA NGS predicts high sensitivity to detect RAS/RAF oncogenic SNVs in CRC and PDAC. MAF £0.34% indicates an assay may not reliably detect RAS/RAF SNVs, despite detection on tissue testing. Most variants from assays that did not detect RAS/RAF had MAF <1% and were not detected on tissue, suggesting potential confounding. These data suggest a practical approach to determining cfDNA assay adequacy, with implications for guiding clinical decisions in CRC and PDAC.

Sidedness-Dependent Prognostic Impact of Gene Alterations in Metastatic Colorectal Cancer in the Nationwide Cancer Genome Screening Project in Japan (SCRUM-Japan GI-SCREEN)

The treatment strategies and prognoses of patients with metastatic colorectal cancer (CRC) differ according to the sidedness of the primary tumor. TP53 gain-of-function (GOF) and non-GOF variants have been reported to be differentially associated with prognosis by sidedness. We aimed to evaluate the sidedness-dependent prognostic impact of gene alterations in metastatic CRC. Patients enrolled between April 2017 and March 2019 were included in this study. Those excluded were individuals whose tumor tissues were obtained after chemotherapy and those who were enrolled in the study more than six months after starting first-line chemotherapy. Finally, we assessed 531 patients who underwent complete gene sequencing. The study revealed a significant difference in overall survival between individuals with left-sided CRC (n = 355) and right-sided colon cancer (CC) (n = 176) when considering the TP53 non-GOF variant, KRAS wild-type, NOTCH1 wild-type, NOTCH1 covariant, NOTCH3 sole variant, and MYC amplification. Multivariate analysis on each side revealed that the TP53 GOF and KRAS variants were independent poor prognostic factors for left-sided CRC (p = 0.03 and p < 0.01, respectively), and the TP53 non-GOF variant, BRAF V600E, and MYC amplification for right-sided CC (p < 0.05, p < 0.01, and p = 0.02, respectively). The NOTCH3 sole variant was an independent and favorable prognostic factor for left-sided CRC (p < 0.01). The prognostic significance of gene alterations differed between left-sided CRC and right-sided CC.

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

BACKGROUND

The 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.

METHODS

We 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.

RESULTS

Forty-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).

CONCLUSIONS

Efficacies of anti-EGFR and BEV therapies may differ between patients with L and RE.

Role of plasma angiogenesis factors in the efficacy of first-line chemotherapy combined with biologics in RAS wild-type metastatic colorectal cancer: Results from the GI-SCREEN CRC-Ukit study

BACKGROUND

Several biomarkers have been established for metastatic colorectal cancer (mCRC). We investigated whether plasma angiogenesis factors could predict the efficacy of biologics combined with chemotherapy in first-line (1L) treatment in patients with RAS wild-type mCRC and the dynamics of plasma angiogenesis factors at progression during 1L treatment.

METHODS

In this multicenter prospective observational study, serial plasma samples were prospectively collected at pretreatment and progression stages; 17 plasma angiogenesis factors were analyzed using the multiplex assay with Luminex® technology. Interactions between the pretreatment measurements and treatment groups on progression-free survival (PFS) and overall survival (OS) in patients with RAS wild-type were assessed using the propensity-score weighted Cox proportional hazards model.

RESULTS

From February 2018 to September 2020, 202 patients were enrolled in the 1L cohort; 133 patients had RAS wild-type (chemotherapy plus bevacizumab [BEV group, n = 33] and plus anti-epidermal growth factor receptor monoclonal antibodies [aEGFR group, n = 100]). A trend of strong interaction on PFS was observed for interleukin-8 (IL-8) (p = 0.0752) and soluble vascular cell adhesion molecule-1 (sVCAM-1) (p = 0.0156). Regarding OS, IL-8 (p = 0.0283), soluble vascular endothelial growth factor-receptor-1 (sVEGFR-1) (p = 0.0777) and sVCAM-1 (p = 0.0011) tended to differentiate the treatment effect. In 112 patients, plasma samples were evaluable for dynamic analysis (57 and 55 from the BEV and aEGFR groups, respectively). In the BEV group, six factors significantly increased during progression, whereas two decreased. In the aEGFR group, three factors significantly increased, and six decreased.

CONCLUSION

Pretreatment plasma IL-8 and sVCAM-1 levels could be predictive biomarkers to distinguish BEV and anti-EGFR mAbs when combined with chemotherapy in the 1L treatment of RAS wild-type mCRC. Several plasma angiogenesis factors showed significant change at progression in 1L chemotherapy plus biologics for RAS wild-type mCRC, which are potential biomarkers for selecting an optimal angiogenesis inhibitor in second-line treatment.

Thermoelectric signature of quantum critical phase in a doped spin-liquid candidate

Quantum spin liquid is a nontrivial magnetic state of longstanding interest, in which spins are strongly correlated and entangled but do not order; further intriguing is its doped version, which possibly hosts strange metal and unconventional superconductivity. A promising candidate of the doped spin liquid is a triangular-lattice organic conductor, κ-(BEDT-TTF)₄Hg_2.89Br₈, recently found to hold metallicity, spin-liquid-like magnetism, and BEC-like superconductivity. The nature of the metallic state with the spin-liquid behaviour is awaiting to be further clarified. Here, we report the thermoelectric signature that mobile holes in the spin liquid background are in a quantum critical state and it pertains to the BEC-like superconductivity. The Seebeck coefficient divided by temperature, S/T, is enhanced on cooling with logarithmic divergence indicative of quantum criticality. Furthermore, the logarithmic enhancement is correlated with the superconducting transition temperature under pressure variation, and the temperature and magnetic field profile of S/T upon the superconducting transition change with pressure in a consistent way with the previously suggested BEC-BCS crossover. The present results reveal that the quantum criticality in a doped spin liquid emerges in a phase, not at a point, and is involved in the unconventional BEC-like nature.

Clinical Validation of Plasma-Based Genotyping for RAS and BRAF V600E Mutation in Metastatic Colorectal Cancer: SCRUM-Japan GOZILA Substudy

PURPOSE

Circulating tumor DNA (ctDNA) genotyping on the basis of next-generation sequencing (NGS) may guide targeted therapy for metastatic colorectal cancer (mCRC). However, the validity of NGS-based ctDNA genotyping for RAS/BRAF V600E mutation assessment and the efficacy of anti-EGFR and BRAF-targeted therapies on the basis of ctDNA results remains unclear.

PATIENTS AND METHODS

The performance of NGS-based ctDNA genotyping for RAS/BRAF V600E mutation assessment was compared with that of a validated polymerase chain reaction-based tissue testing in patients with mCRC enrolled in the GOZILA study, a nationwide plasma genotyping study. The primary end points were concordance rate, sensitivity, and specificity. The efficacy of anti-EGFR and BRAF-targeted therapies on the basis of ctDNA were also evaluated.

RESULTS

In 212 eligible patients, the concordance rate, sensitivity, and specificity were 92.9% (95% CI, 88.6 to 96.0), 88.7% (95% CI, 81.1 to 94.0), and 97.2% (95% CI, 92.0 to 99.4) for RAS and 96.2% (95% CI, 92.7 to 98.4), 88.0% (95% CI, 68.8 to 97.5), and 97.3% (95% CI, 93.9 to 99.1) for BRAF V600E, respectively. In patients with a ctDNA fraction of ≥1.0%, sensitivity rose to 97.5% (95% CI, 91.2 to 99.7) and 100% (95% CI, 80.5 to 100.0) for RAS and BRAF V600E mutations, respectively. In addition to a low ctDNA fraction, previous chemotherapy, lung and peritoneal metastases, and interval between dates of tissue and blood collection were associated with discordance. The progression-free survival of anti-EGFR therapy and BRAF-targeted treatment was 12.9 months (95% CI, 8.1 to 18.5) and 3.7 (95% CI, 1.3 to not evaluated) months, respectively, for matched patients with RAS/BRAF V600E results by ctDNA.

CONCLUSION

ctDNA genotyping effectively detected RAS/BRAF mutations, especially with sufficient ctDNA shedding. Clinical outcomes support ctDNA genotyping for determining the use of anti-EGFR and BRAF-targeted therapies in patients with mCRC.

Clinical outcomes of patients diagnosed with cancer of unknown primary or malignancy of undefined primary origin who were referred to a regional cancer center

BACKGROUND

A regional cancer hospital has been identified to be crucial in the management of malignancies of undefined primary origin (MUO) and cancer of unknown primary (CUP). This hospital primarily consists of oncologists with expertise in CUP, pathologists, and interventional radiologists. Early consultation or referral of MUO and CUP to a cancer hospital is deemed important.

METHODS

This study retrospectively collected and analyzed the clinical, pathological, and outcome data of all patients (n = 407) referred to the Aichi Cancer Center Hospital (ACCH) in Japan over an 8-year period.

RESULTS

In total, 30% of patients were referred for a second opinion. Among 285 patients, 13% had non-neoplastic disease or confirmed primary site and 76% had confirmed CUP (cCUP), with 29% of cCUP being identified as favorable risk. In 155 patients with unfavorable-risk CUP, 73% had primary sites predicted by immunohistochemistry (IHC) and distribution of metastatic sites, whereas 66% of them received site-specific therapies based on the predicted primary sites. The median overall survival (OS) was found to be poor in patients with MUO (1 month) and provisional CUP (6 months). In addition, the median OS of 206 patients with cCUP treated at the ACCH was 16 months (favorable risk, 27 months; unfavorable risk, 12 months). No significant difference was noted in OS between patients with non-predictable and predictable primary-sites (13 vs 12 months, p = 0.411).

CONCLUSION

The outcome of patients with unfavorable-risk CUP remains to be poor. Site-specific therapy based on IHC is not recommended for all patients with unfavorable-risk CUP.

Structural origins of the unusual thermal stability of amorphous CuxGe50-xTe50(0⩽x⩽33.3)

We have investigated the local atomic structures of several compositions of the amorphous phase of the system Cu_xGe50-xTe₅₀(0⩽x⩽33.3), based on extended x-ray absorption fine-structure as well as anomalous x-ray scattering experiments, and discuss the unusual trend regarding their thermal stability as a function of the Cu content. At low concentrations (x⩽15), Cu atoms tend to agglomerate in flat nanoclusters reminiscent of the crystalline phase of metallic Cu, leading to a more and more Ge-deficient Ge-Te host network structure with growing Cu content and an increasing thermal stability. At higher Cu concentrations (x⩾25), Cu is incorporated into the network, leading to an overall weaker bonding situation which is associated with a decreasing thermal stability.

Impact of omitting fluorouracil from FOLFIRI plus bevacizumab as second-line chemotherapy for patients with metastatic colorectal cancer

PURPOSE

Fluorouracil, leucovorin, and irinotecan (FOLFIRI) plus bevacizumab is the standard second-line chemotherapy for patients with metastatic colorectal cancer (mCRC) who are refractory or intolerant to fluoropyrimidines and oxaliplatin. However, the benefits of incorporating fluoropyrimidines into second-line chemotherapy for patients with mCRC who are refractory to fluoropyrimidines are unknown.

METHODS

We retrospectively evaluated patients with mCRC who were administered irinotecan plus bevacizumab or FOLFIRI plus bevacizumab as second-line chemotherapy at a single institution from January 2010 to April 2020. We compared the efficacy and safety of irinotecan plus bevacizumab (IRI group) with those of FOLFIRI plus bevacizumab (FOLFIRI group).

RESULTS

Of the 255 enrolled patients, 107 (IRI/FOLFIRI group, 31/76 patients) were eligible for analysis. After a median follow-up of 13.1 months (range 1.2-48.4) and 14.3 months (range 0.9-46.5) for the IRI and FOLFIRI groups, respectively, the median progression-free survival was 6.4 months and 5.8 months [adjusted hazard ratio (aHR), 0.82; 95% confidence interval (CI) 0.50-1.34, p = 0.44] and the median overall survival was 16.6 months and 16.5 months (aHR, 1.01; 95% CI 0.59-1.69; p = 0.97) in the IRI and FOLFIRI groups, respectively. All-grade nausea, stomatitis, neutropenia, thrombocytopenia, Grade 3/4 neutropenia, and febrile neutropenia occurred more frequently in the FOLFIRI group than in the IRI group.

CONCLUSION

Our study suggests omitting fluorouracil from FOLFIRI plus bevacizumab as the second-line chemotherapy decreases adverse events without affecting the treatment efficacy in patients with mCRC who are refractory to fluoropyrimidines. Further randomized prospective studies are warranted to validate our result.

Trajectory for the Regulatory Approval of a Combination of Pertuzumab Plus Trastuzumab for Pre-treated HER2-positive Metastatic Colorectal Cancer Using Real-world Data

Utilizing real-world data (RWD) for effective clinical implementation is becoming more and more appealing as the cost of drug development rises, especially for patients with rare diseases and rare molecular subtypes for whom conducting randomized controlled trials is challenging. If a regulatory approval methodology based on RWD as an external control group can be established, drug development for rarer fractions can be accelerated by lowering costs and time, as well as reducing physical and emotional burdens on both patients and healthcare professionals. Since 2017, we have been prospectively collecting the clinical data of standard therapies in patients with rare molecular fractions under the SCRUM-Japan Registry platform, which is a qualified registry utilized as external control data for regulatory submission. Based on the results of the phase II TRIUMPH study (UMIN000027887) and the extracted data from the SCRUM-Japan Registry, the pharmaceutical company submitted an application for pertuzumab and trastuzumab in patients with HER2-positive metastatic colorectal cancer in April 2021. Pertuzumab and trastuzumab were approved as expanded indications on March 28, 2022, as 6 cases out of 14 extracted from the SCRUM-Japan Registry were classified and utilized as "evaluation material" under the review process of the Pharmaceuticals and Medical Devices Agency (PMDA). Through the TRIUMPH study and the SCRUM-Japan Registry, we have paved the way for regulatory approval of RWD in Japan. In future, we must define the steps for constructing regulatory-grade registries and the method/process for utilizing RWD by accumulating case experiences.

Efficacy of Targeted Trials and Signaling Pathway Landscape in Advanced Gastrointestinal Cancers From SCRUM-Japan GI-SCREEN: A Nationwide Genomic Profiling Program

PURPOSE

Genomic profiling programs have been implemented to apply next-generation sequencing (NGS) for facilitating trial enrollment. SCRUM-Japan GI-SCREEN is a large-scale genomic profiling program in advanced gastrointestinal cancers using a validated genomic assay with the goal of facilitating enrollment in targeted clinical trials, generating real-world data, and performing clinicogenomic analysis for biomarker discovery.

PATIENTS AND METHODS

Genotyping of tumor tissue samples from 5,743 patients with advanced gastrointestinal cancers enrolled in GI-SCREEN was centrally performed with NGS. Patients were enrolled in matched trials of targeted agents affiliated with GI-SCREEN on the basis of genotyping results.

RESULTS

A total of 11 gastrointestinal cancers were included, with colorectal cancer being the most common. The median age ranged from 59 to 70.5 years across cancer types. Patients enrolled after initiation of first-line treatment had significantly longer overall survival (OS) than that before treatment initiation with a median survival time difference of 8.9 months and a hazard ratio (HR) ranging from 0.25 to 0.73 across cancer types, demonstrating an immortal time bias. One hundred and forty-nine patients received matched therapies in clinical trials on the basis of their identified alterations. Among patients with colorectal cancer harboring actionable alterations, the median OS was significantly longer in patients who received matched therapies in trials than in those who did not (HR, 0.52; 95% CI, 0.26 to 1.01; P = .049). Cancer-specific pathway alterations were significantly associated with shorter survival and related to primary resistance to matched trial therapies.

CONCLUSION

Our genomic profiling program led to patient enrollment in targeted clinical trials and improved survival of patients with colorectal cancer who received matched therapies in clinical trials. To avoid immortal time bias, precautions are needed when using data from patients who have undergone NGS testing after initiation of the evaluated treatment line.

Predictors of therapeutic efficacy of anamorelin in patients with gastric, pancreatic, and colorectal cancer

331

Background: Anamorelin is a highly selective ghrelin receptor agonist that improves appetite and increases lean body mass in patients (pts) with cachexia. We aimed to investigate the predictors of therapeutic efficacy of anamorelin in pts with gastrointestinal cancer. Methods: This retrospective study included pts with gastric cancer (GC), pancreatic cancer (PC), and colorectal cancer (CRC) treated with anamorelin at our institution between May 2021 and July 2022. Glasgow Prognostic Score (GPS) was defined as follows: GPS 0: CRP≤1.0 (mg/dL) and Alb≥3.5 (g/dL), GPS 1: either CRP>1.0 or Alb<3.5, GPS 2: CRP>1.0 and Alb<3.5. The endpoints were the response rate (RR) of anamorelin and time to treatment failure (TTF). RR was defined as the proportion of appetite improvement within 3 weeks of anamorelin, and TTF was defined as the time from the start of anamorelin to discontinuation due to insufficient response. The observation period lasted 12 weeks. RR was analyzed by univariate and multivariate logistic regression analyses, and TTF by competing risk analysis. In the competing analysis, discontinuation of anamorelin due to worse symptoms, hospital transfer for poor condition, and adverse events (AEs) were considered as competing events. Results: A total of 103 pts were included; median age was 70 (range: 37–84) years, 61 pts (59%) were men, and 17 pts (17%) had an ECOG PS ≥2. The proportion of GC/PC/CRC were 43/42/16%; median body mass index (BMI) was 19.9 (range: 14.4–26.8) kg/m2. The treatment line for 1st/2nd/≥3rd/others was 51/13/14/22%, respectively. GPS was 0/1/2 in 21/30/49%, respectively. Except for treatment line, there were no significant differences in patient characteristics according to the cancer type. A total of 12 pts discontinued treatment owing to AEs (nausea, 3; epigastric distress, 2; fatigue, 2; poor physical condition, 2; staggering, 1; pulsation, 1; diarrhea, 1 pts). The RR was 42%. Pts with GPS 2 had less improvement in appetite than those with GPS 0 or 1 (26% vs. 56%, adjusted odds ratio [95% confidence interval (95%CI)]:0.22 [0.07–0.69], p=0.009). The RR of pts with GC, PC, and CRC were 44%, 42%, and 41%, respectively. The cumulative incidence of discontinuation of anamorelin after 12 weeks was higher in pts with GPS 2 than in those with GPS 0 or 1 (46% vs. 30%). The TTF in pts with GPS 2 was significantly shorter than that in pts with a GPS 0 or 1 (adjusted subdistributional hazard ratio [95%CI]:2.80 [1.37–5.72], p=0.005). There was no statistically significant difference in TTF by cancer type, although TTF was shorter in GC and PC than in CRC. Other factors, including age, sex, baseline BMI, ECOG PS, lines of therapy, and cancer type did not correlate with RR and TTF. Conclusions: In pts with a GPS of 0 or 1, anamorelin showed better appetite improvement and a longer treatment effect than in those with GPS 2. TTF was shorter in pts with GC and PC; therefore, the timing of use should be carefully considered.

The impacts of initiating regorafenib with reduced dose on treatment outcomes in metastatic colorectal cancer

133

Background: Since the results of the ReDOS study were published, starting regorafenib (REG) at a reduced dose is now considered a treatment option for patients with metastatic colorectal cancer (mCRC). However, the impact of starting REG at a reduced dose on treatment outcomes in the real-world setting has not been fully investigated. Methods: We retrospectively analyzed patients who received REG for mCRC at 4 institutions between May 2013 and December 2020. These patients were divided into two groups: those who started REG before (Period A) and after (Period B) the ReDOS study publication (May 2018). The treatment outcomes between Period A and B were compared in this analysis. Results: A total of 573 patients were evaluated (385 in Period A and 188 in Period B, respectively). In Period B, significantly more patients started REG with reduced dose (34.3% vs. 75.5%, p< 0.001). The median time to first dose reduction was 32.0 days [95% CI: 29.1-34.9] in Period A and 61.0 days [95% CI: 33.7-88.9] in Period B, which was significantly longer in Period B (HR = 0.685, p= 0.003). Both any grades and ≥grade3 hand foot skin reaction (HFSR) were significantly less frequent in Period B than in Period A (any grades: 65.5% vs 54.8%, p= 0.017, ≥grade3: 21.3% vs 14.4%, p= 0.054). The median time to onset of any grades HFSR was 16.0 days [95% CI: 13.6-18.4] in Period A and 28.0 days [95% CI: 15.6-40.4] in Period B, which was significantly longer in Period B (HR = 0.738, p= 0.007). The median overall survival was 6.7 months [95% CI: 5.9-7.4] in Period A, and 5.4 month [95% CI: 4.3-6.5] in Period, respectively (HR = 1.105, p= 0.281). The median progression free survival was 2.0 months [95% CI: 1.9-2.1] in Period A and 2.1 months [95% CI: 1.8-2.4] in Period B, respectively (HR = 1.064, p= 0.498). Conclusions: Our results suggest that starting REG at a reduced dose may contribute to reducing the frequency and delaying the onset of HFSR, whereas it may not affect efficacy.

Pembrolizumab for previously treated, microsatellite instability–high/mismatch repair–deficient advanced colorectal cancer: final analysis of KEYNOTE-164

BACKGROUND

Pembrolizumab demonstrated durable clinical benefit and manageable safety in previously treated advanced or metastatic microsatellite instability-high (MSI-H)/mismatch repair deficient (dMMR) colorectal cancer (CRC) in the phase 2 KEYNOTE-164 study. Results from the final analysis are presented.

METHODS

Eligible patients had unresectable or metastatic MSI-H/dMMR CRC and ≥2 prior systemic therapies (cohort A) or ≥1 prior systemic therapy (cohort B). Patients received pembrolizumab 200 mg intravenously every 3 weeks for ≤35 cycles. The primary end-point was objective response rate (ORR) assessed per Response Evaluation Criteria in Solid Tumors, version 1.1 by blinded independent central review. Secondary end-points included duration of response (DOR), progression-free survival (PFS), overall survival (OS), and safety and tolerability.

RESULTS

Sixty-one patients in cohort A and 63 patients in cohort B were enroled; median follow-up was 62.2 months and 54.4 months, respectively. ORR was 32.8% (95% CI, 21.3%-46.0%) in cohort A and 34.9% (95% CI, 23.3%-48.0%) in cohort B. Median DOR was not reached (NR) in either cohort. Median PFS was 2.3 months (95% CI, 2.1-8.1) in cohort A and 4.1 months (95% CI, 2.1-18.9) in cohort B. Median OS was 31.4 months (95% CI, 21.4-58.0) in cohort A and 47.0 months (95% CI, 19.2-NR) in cohort B. No new safety signals were observed. Nine patients who initially responded experienced disease progression off therapy and received second-course pembrolizumab. Six patients (66.7%) completed an additional 17 cycles of pembrolizumab, and 2 patients achieved a partial response.

CONCLUSIONS

Pembrolizumab continued to show durable antitumor activity, prolonged OS, and manageable safety in patients with previously treated MSI-H/dMMR CRC.

CLINICAL TRIAL REGISTRY INFORMATION

ClinicalTrials.gov, NCT02460198.

Prevention and management of cetuximab-related hypomagnesemia

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Background: Cetuximab is an epidermal growth factor receptor monoclonal antibody indicated for the treatment of squamous cell carcinoma of the head and neck and RAS wild-type metastatic colorectal cancer. Hypomagnesemia is a reversible adverse event associated with cetuximab treatment. Here, we provide the key considerations in prevention and management of cetuximab-related hypomagnesemia events in clinical practice. Methods: A PubMed literature search was conducted for articles published between 18 March 2012 and 18 March 2022 using “cetuximab” and “hypomagnesemia” as keywords. Of the 75 articles retrieved, 20 were considered relevant and are included here.Articles were excluded if they focused on hypomagnesemia-associated clinical benefits. Data were summarized and grouped into the following categories: risk and risk factors; monitoring; prevention; and management. Results: The relative risk of grade 3/4 hypomagnesemia following cetuximab therapy appears to be approximately 1.5 times higher for colorectal cancer compared with head and neck cancer. Several risk factors have been identified including age, comorbidities, treatment duration, baseline electrolyte levels, concomitant platinum-based chemotherapy, and polypharmacy. Although the frequencies of hypomagnesemia events vary between the studies identified, data from the included meta-analyses suggest that the incidence of grade 3/4 hypomagnesemia is around 4% among patients receiving cetuximab therapy. Early and regular monitoring of magnesium levels is recommended ideally every 4 to 8 weeks, especially in patients at high risk of serious complications, and up to 8 weeks following treatment cessation. Proposed proactive prophylactic interventions include magnesium supplementation for patients with baseline magnesium levels < 1.8 mg/dL, to prevent severe hypomagnesemia. The management approach depends on the degree of hypomagnesemia, the symptoms and risk factors, and may include supplementation with oral magnesium salts and/or parenteral forms; intravenous forms may be preferred due to low bioavailability and gastrointestinal adverse events related to oral supplements. While recommendations for initiating magnesium replacement in grade 1 (> 1.2 mg/dL) and grade 2 (0.9–1.2 mg/dL) hypomagnesemia events vary, magnesium supplementation should be given to patients with grade 3 (0.7–0.9 mg/dL) or grade 4 (< 0.7 mg/dL) hypomagnesemia, due to high risk of serious adverse cardiac events. If magnesium levels do not improve or continue to decrease despite supplementation, a pause in cetuximab administration may be considered. Conclusions: Hypomagnesemia is a reversible and manageable cetuximab-related adverse event and should not interfere with treatment outcomes. A periodic check of magnesium levels during treatment with cetuximab is recommended.

Clinical Performance of the Consensus Immunoscore in Colon Cancer in the Asian Population from the Multicenter International SITC Study

BACKGROUND: In this study, we evaluated the prognostic value of Immunoscore in patients with stage I−III colon cancer (CC) in the Asian population. These patients were originally included in an international study led by the Society for Immunotherapy of Cancer (SITC) on 2681 patients with AJCC/UICC-TNM stages I−III CC. METHODS: CD3+ and cytotoxic CD8+ T-lymphocyte densities were quantified in the tumor and invasive margin by digital pathology. The association of Immunoscore with prognosis was evaluated for time to recurrence (TTR), disease-free survival (DFS), and overall survival (OS). RESULTS: Immunoscore stratified Asian patients (n = 423) into different risk categories and was not impacted by age. Recurrence-free rates at 3 years were 78.5%, 85.2%, and 98.3% for a Low, Intermediate, and High Immunoscore, respectively (HR[Low-vs-High] = 7.26 (95% CI 1.75−30.19); p = 0.0064). A High Immunoscore showed a significant association with prolonged TTR, OS, and DFS (p < 0.05). In Cox multivariable analysis stratified by center, Immunoscore association with TTR was independent (HR[Low-vs-Int+High] = 2.22 (95% CI 1.10−4.55) p = 0.0269) of the patient’s gender, T-stage, N-stage, sidedness, and MSI status. A significant association of a High Immunoscore with prolonged TTR was also found among MSS (HR[Low-vs-Int+High] = 4.58 (95% CI 2.27−9.23); p ≤ 0.0001), stage II (HR[Low-vs-Int+High] = 2.72 (95% CI 1.35−5.51); p = 0.0052), low-risk stage-II (HR[Low-vs-Int+High] = 2.62 (95% CI 1.21−5.68); p = 0.0146), and high-risk stage II patients (HR[Low-vs-Int+High] = 3.11 (95% CI 1.39−6.91); p = 0.0055). CONCLUSION: A High Immunoscore is significantly associated with the prolonged survival of CC patients within the Asian population.

Colon cancer with extensive invasion of the abdominal wall treated with neoadjuvant chemotherapy and a free anterolateral thigh flap

Background

The treatment of locally advanced colon cancer is challenging, particularly when there is invasion of the abdominal wall. In such cases, balancing the securing of margins and sufficiently repairing abdominal wall defects is important, but difficult when the extent of invasion is large.

Case presentation

A 34-year-old male was referred to our hospital with abdominal pain and diagnosed with obstructive transverse colon cancer. He had undergone ileo-sigmoid colostomy at his previous hospital. The tumor was massive and invaded the abdominal wall (maximum diameter: approximately 12 cm), and was accompanied by regional lymph node swelling. No distant metastasis was detected. We diagnosed the tumor as cT4bN2bM0 Stage IIIC locally advanced transverse colon cancer and planned neoadjuvant chemotherapy. After two courses of FOLFOXIRI (5-fluorouracil, leucovorin, oxaliplatin, and irinotecan), he developed an entero-cutaneous fistula due to tumor penetration and required emergency diverting ileostomy construction. After the procedure, contrast-enhanced computed tomography showed good tumor shrinkage. As a result, the planned chemotherapy was canceled and he underwent radical resection of the tumor. En bloc extended right hemicolectomy was performed with excision of the fistula, ensuring a sufficient margin. The post-excision defect at the anterior abdominal wall involved 11 × 16 cm of fascia and 6 × 9 cm of skin located in the middle of the abdomen. A free anterolateral thigh flap was harvested from the right thigh and vascular pedicle was anastomosed to the right gastroepiploic artery and vein. The fascia lata, which was included in the anterolateral thigh flap, was sutured onto the abdominal wall fascia as inlay fashion to reconstruct the abdominal wall defect. Histopathology revealed moderately differentiated adenocarcinoma of the colon with no tumor cells in the abdominal wall tissue [post-chemotherapeutic state, therapy effect: Grade 1b; Stage IIA (ypT3N0M0)]. All resected margins of the specimen were free from adenocarcinoma. He was discharged on postoperative day 16.

Conclusion

We report a case of colon cancer extensively invading the abdominal wall, which was completely resected. The abdominal wall defect was reconstructed with a free anterolateral thigh flap after tumor shrinkage with neoadjuvant chemotherapy. We present an efficient strategy for managing locally advanced colon cancer with extensive abdominal wall invasion.

Recommendations related to the analytical equivalence assessment of gene panel testing

Advances in cancer genome care over the past few years have included the development of gene panel testing for various biomarkers. This article summarizes issues and provides recommendations related to analytical performance evaluations for new oncology gene panels. The scope of these recommendations includes comprehensive genomic profiling assays related to gene panel testing that uses histological or serum specimens to detect gene mutations. As a research project of the Japan Agency for Medical Research and Development Research on Regulatory Science of Pharmaceuticals and Medical Devices, we convened the working group committee that consisted of more than 30 experts from academia, industry, and government. We have discussed the points that should be considered to allow maximal simplification of assessments using clinical specimens in evaluating accuracy and limit of detection in equivalence and analytical performance for three years. We provide recommendations specific to each type of gene mutation as well as to reference standards or specimens used for evaluations. In addition, in order to facilitate the discussion on the analytical performance of gene panel tests by multidisciplinary tumor boards of hospitals, the present recommendations also describe the items that companies are expected to provide information on in their packaging inserts and reports, and the items that are expected to be discussed by multidisciplinary tumor boards. Our working group document will be important for participants in multidisciplinary tumor boards including medical oncologists and genome scientists, and developers of gene panels not only in Japan but also in other countries.

Analysis of plasma angiogenesis factors on the efficacy of first-line (1L) chemotherapy (chemo) combined with biologics in RAS wild-type metastatic colorectal cancer (mCRC): Results from GI-SCREEN CRC Ukit study

3530

Background: Angiogenesis factors have been reported as prognostic and predictive biomarkers of angiogenesis inhibitors for mCRC (Weickhardt AJ. Br J Cancer 2015. Tabernero J. Ann Oncol 2018). We investigated whether plasma angiogenesis factors could predict the efficacy of biologics combined with chemo in 1L treatment in patients (pts) with RAS wild-type mCRC. Methods: Serial plasma samples were prospectively collected at the time points of pre- and post-treatments in mCRC pts receiving biologics in either 1L or 2nd-line (2L) chemo. From Sep 2017 to Dec 2020, 497 pts were enrolled [1L chemo plus bevacizumab (1L BEV, n=102), 1L chemo plus anti-EGFR antibody (1L aEGFR, n=100), 2L chemo plus bevacizumab (n=100), 2L FOLFIRI plus RAM (n=99), 2L FOLFIRI plus aflibercept (n=85) and other treatment (n=11)]. Total of 17 plasma angiogenesis factors (HGF, PlGF, VEGF-A, VEGF-D, Angiopoietin-2, IFN-γ, IL-6, IL-8, sNeuropilin-1, TSP-2, OPN, sVEGFR1, sVEGFR2, sVEGFR3, sICAM-1, sVCAM-1, and TIMP-1) were analyzed by the multiplex assay with Luminex® technology. Interactions of their pre-treatment measurements with treatment groups on PFS and OS were assessed via Cox proportional hazards model. The strength of interactions was estimated using a propensity score weighting analysis, and the continuous plasma angiogenesis variables were categorized according to the median. The significance level in the interaction was defined as p≤0.1. Results: 133 pts were included in adjusted RAS wild-type 1L cohort (1L BEV: n=33, 1L aEGFR [reference]: n=100). Baseline characteristics of adjusted RAS wild-type 1L cohort were as follows; median age 64 years; male 62.4%; left-sided tumor 88.7%; triplet chemo 15.0%. Propensity-score weighted Cox model for OS showed significant interactions in IL-8 (median 8.03 pg/mL, high: HR 1.738, p=0.0838, Low: HR 0.479, p=0.2624, interaction p=0.0283), sVEGFR-1 (median 1,350 pg/mL, high: HR 0.333, p=0.1770, Low: HR 1.311, p=0.3004, interaction p=0.0777), and sVCAM-1 (median 1,020,000 pg/mL, high: HR 0.100, p=0.0558, Low: HR 1.616, p=0.1765, interaction p=0.0011). In terms of PFS, there were significant interactions in IL-8 (high: HR 1.322, p=0.0418, Low: HR 0.517, p=0.0528, interaction p=0.0752) and sVCAM-1 (high: HR 0.285, p=0.0414, Low: HR 1.200, p=0.7725, interaction p=0.0156). Conclusions: Pre-treatment plasma IL-8 and sVCAM-1 could be predictive biomarkers for efficacy of biologics combined with chemo in 1L treatment of RAS wild-type mCRC. Clinical trial information: UMIN000028616. [Table: see text]

Identification of an optimal circulating tumor DNA (ctDNA) shedding threshold to detect actionable driver mutations in colorectal and pancreatic adenocarcinoma

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Background: In colorectal cancer (CRC), mutations in KRAS, NRAS, and BRAF predict resistance to anti-EGFR therapies. In pancreatic ductal adenocarcinoma (PDAC), ~90% of patients harbor KRAS mutations, while KRAS wild-type tumors often have clinically actionable fusion alterations. Thus, in both cancers, the accurate ascertainment of RAS and BRAF driver status is essential. Sequencing of cell-free DNA (cfDNA) from plasma allows convenient assessment of a tumor’s molecular profile, but sensitivity can be limited by low ctDNA shedding. We sought to establish a ctDNA shedding threshold at which actionable driver mutations can be reliably detected. Methods: Molecular reports and matched clinical data were obtained from the Duke Molecular Registry of Tumors and the SCRUM-Japan GOZILA and GI-SCREEN. CRC or PDAC patients with a pathogenic KRAS, NRAS, or BRAF activating point mutation (“driver”) present on tissue next-generation sequencing (NGS) assays and who also had cfDNA assay available were included. Tissue NGS included Foundation One CDx and Oncomine Comprehensive Assay. Guardant 360 (G360) was the sole plasma cfDNA assay. 131 CRC and 24 PDAC cases with 189 total G360 assays met criteria and were included. Samples were analyzed according to detection of the driver mutation and the maximum mutant allele frequency (MAF) of non-driver mutations on G360. An optimal cut-point for max MAF was explored among the CRC and PDAC patients using a maximally selected Wilcoxon rank statistic method. Results: 76.8% of driver mutations were in KRAS, 22.6% in BRAF, and 1.9% in NRAS with an overlap of 1 BRAF and 1 NRAS mutation with a KRAS mutation. Overall sensitivity of G360 for drivers was 83.0% for CRC and 54.2% for PDAC. No variants were detected on G360 in 9.1% of CRC and 37.5% of PDAC. Sensitivity for driver mutations increased with higher maximum non-driver MAF, with MAF > 1% predicting sensitivity > 98% (Table). Optimal cut-point analysis identified MAF of > 0.34% (p < 0.0001), above which the driver was identified in 97% of patients and below which only 27%. Conclusions: In our study, non-driver MAF > 1% on cfDNA NGS predicts high sensitivity for RAS and BRAF mutations and thus is adequate to guide clinical decisions such as anti-EGFR therapy in CRC, evaluation for fusions in PDAC, and validity in clinical trials. MAF ≤0.34% is a clear threshold to consider an assay inadequate and thus seek alternative testing. Sensitivity rises for MAF between 0.35 and 1% but will require greater patient numbers to establish clinically relevant sensitivity thresholds. These results will be updated with additional data for final presentation. [Table: see text]

Plasma RAS dynamics and anti-EGFR rechallenge efficacy in patients with RAS/BRAF wild-type metastatic colorectal cancer: REMARRY and PURSUIT trials

3518

Background: Rechallenge with anti-EGFR monoclonal antibody (EGFR mAb) showed certain activities in patients (pts) with RAS/ BRAF V600E wild-type (wt) metastatic colorectal cancer (mCRC), particularly in pts with negative plasma RAS (p RAS) mutation by circulating-tumor DNA (ctDNA) assay at ‘just before’ the rechallenge therapy. However, the efficacy is unknown in pts with RAS/ BRAF wt mCRC whose p RAS was converted to positive once during or after EGFR mAb. Therefore, we conducted REMARRY, a prospective longitudinal study to investigate the p RAS dynamics, and PURSUIT trials, a phase II trial to investigate the efficacy of EGFR mAb rechallenge in pts with p RAS wt just before rechallenge therapy. Methods: The eligibility criteria of REMARRY trial included RAS/ BRAF V600E wt mCRC; ECOG PS 0-1; CR or PR during EGFR mAb; and a refractory ≤ 2 months from the last administration of EGFR mAb. p RAS status by the BEAMing method was prospectively monitored at timepoints of progression on EGFR mAb and each subsequent therapy. The eligibility criteria of PURSUIT trial included enrollment in the REMARRY trial with confirmed p RAS wt prior to enrollment in PURSUIT trial; being refractory or intolerant to fluoropyrimidine, oxaliplatin, and irinotecan; and ≥ 4 months of EGFR mAb-free interval. Study treatment was rechallenge with panitumumab + irinotecan (6 mg/kg + 150 mg/m2 q2wks). Primary endpoint was a confirmed objective response rate (ORR) according to RECIST v1.1. The required number of pts was 45, with a null ORR of 10%, an expected ORR of 25%, power of 85%, and one-sided α of 0.05. Results: Between May 2019 and May 2021, 183 pts with 343 timepoints (median, 2) were enrolled in REMARRY trial from 27 institutions, and 50 pts were enrolled in PURSUIT trial; median age, 68 years; left-sided primary, 44 pts; prior EGFR mAb, 1st/2nd/≥3rd lines was 28/6/16 pts; and p RAS status at progression on prior EGFR mAb, wt/mutant (mt)/unknown in 31/7/12 pts. Confirmed ORR and disease control rate were 14% (90% CI, 7.8%–23.9%) and 80% (95% CI, 67.0%–88.8%), respectively. In addition, 4 pts showed an unconfirmed PR. With a median follow-up time of 8.7 months, median progression-free survival was 3.6 months (95% CI, 3.0 – 4.7 months). The subgroup analysis showed a significantly higher confirmed ORR in pts with a longer EGFR mAb-free interval than a shorter one (> vs. < 365 days, 44.4% vs. 7.3%, p = 0.0037). Without any unexpected safety signals, 58.5% of pts had ≥ grade 3 adverse events. Of 31 patients with wt p RAS at progression on prior EGFR mAb, 5 had a confirmed response (ORR, 16%), whereas no response was observed in patients with 7 p RAS mt (ORR, 0%) (p = 0.25). Conclusions: The primary endpoint of confirmed ORR was not met; however, pts with p RAS wt at progression on prior EGFR mAb may benefit from rechallenge with, implying a lack of or worse response if p RAS becomes positive even once during or after EGFR mAb. Clinical trial information: REMARRY: UMIN000036424 PURSUIT: jRCTs031190096.

Clinical impact of MAPK pathway alterations in advanced biliary tract cancer (BTC): SCRUM-Japan GOZILA and COLOMATE international collaboration

4086

Background: Abnormalities in the MAPK pathway are potential therapeutic targets in various cancers. However, the clinical impact of alterations in the MAPK pathway in BTC have not been elucidated, especially outside of canonical mutations in KRAS and BRAF. We investigated the clinical outcomes of advanced BTC with MAPK pathway alterations treated with chemotherapy in Japan and the United States. Methods: Patients with advanced BTC who received gemcitabine plus cisplatin as first-line therapy were included from the GOZILA study in Japan and Duke Molecular Registry of Tumors in the US. Genetic abnormalities were detected by Guardant360, a cell-free DNA assay, in Japan and by blood or tissue-based next-generation sequencing (NGS) at Duke University. Two hundred and seven patients with BTC from Japan were included in an exploratory cohort to evaluate the association of MAPK alterations with overall survival (OS) according to MAPK alteration status. One hundred and ten patients with BTC from both Japan and the US harboring oncogenic alterations in the MAPK pathway were included in a biomarker selected cohort to assess the association of specific MAPK alterations with OS. Multivariate analysis was performed using a Cox regression model based on a univariate p-value < 0.2. Results: MAPK pathway-related oncogenic alterations detected in each cohort are shown in the table below. In the exploratory cohort, median OS was shorter for patients with MAPK alterations vs. no MAPK alteration (15.9 m vs. 24.9 m, log-rank p = 0.001). Based on univariate analysis, the following covariates were selected for multivariate analyses: age, prior resection, and MAPK pathway alteration in the exploratory cohort; country, the timing of NGS, distant metastasis, KRAS amplification, and BRAF class 2 mutation in the biomarker selected cohort. In the exploratory cohort, multivariate analysis identified MAPK pathway alterations as an independent predictor of shorter OS with a HR of 1.92 (95% CI = 1.28-2.87, p = 0.001). In the biomarker selected cohort, multivariate analysis identified BRAF class 2 mutations and KRAS amplification as independent predictors of shorter OS with a HR of 16.2 (95% CI = 3.26-80.8, p = 0.001) and 5.97 (95% CI = 1.74-19.3, p = 0.002) respectively. Conclusions: MAPK pathway alterations, especially BRAF class 2 mutation and KRAS amplification, had a significant negative impact on clinical outcomes in BTC receiving first-line chemotherapy. These results are newly confirmed in BTC. [Table: see text]

Effects of Metastatic Sites on Circulating Tumor DNA in Patients With Metastatic Colorectal Cancer

PURPOSE

Low concordance between plasma-based and tissue-based tests for determining the RAS mutational status have been reported in some but not all patients with limited-extent metastatic colorectal cancer (mCRC). In this study, we investigated the relationship between metastatic site and circulating tumor DNA (ctDNA) detection using ctDNA genotyping, an alternative to tissue genotyping for precision oncology.

MATERIALS AND METHODS

We investigated the relationship between metastatic site and ctDNA detection using Guardant360, a next-generation sequencing ctDNA assay, in mCRC patients with single-organ metastasis in the SCRUM-Japan GOZILA study (UMIN000029315).

RESULTS

Of 1,187 patients with mCRC enrolled in GOZILA, 138 were eligible (49 with liver-only, 15 with lymph node-only, 27 with peritoneum-only, and 47 with lung-only metastases). The concordance of RAS/BRAF status between Guaradant360 and tissue in vitro diagnostic tests was 95.9% in patients with liver-only, 80.0% in lymph node-only, 56.0% in peritoneum-only, and 65.9% in lung-only metastases. ctDNA fraction, as measured by the median maximum variant allelic fraction (max VAF), and median number of detected variants were 23.1% and five in liver-only, 6.0% and five in lymph node-only, 0.4% and three in peritoneum-only, and 0.4% and three in lung-only metastases, respectively (all P < .001, Kruskal-Wallis test). Few patients with liver-only (2.0%) and lymph node-only metastasis (13.3%) had a max VAF < 0.2%, which is required to ensure a detection limit of 95%, but max VAF was more frequently < 0.2% in patients with lung-only (27.7%) or peritoneum-only metastasis (29.6%).

CONCLUSION

Patients with lung-only and peritoneum-only metastatic disease have significantly lower levels of ctDNA, suggesting decreased clinical sensitivity for subclonal variants. This observation suggests that such patients may benefit from concurrent tissue and plasma testing to provide optimal genotyping for subsequent therapy selection.

Impact of Circulating Tumor DNA-Based Detection of Molecular Residual Disease on the Conduct and Design of Clinical Trials for Solid Tumors

Earlier detection of cancer recurrence using circulating tumor DNA (ctDNA) to detect molecular residual disease (MRD) has the potential to dramatically affect cancer management. We review evidence supporting the use of ctDNA as a biomarker for detection of MRD and highlight the potential impact that ctDNA testing could have on the conduct of clinical trials.

A randomized, double-blind, phase III study comparing trifluridine/tipiracil hydrochloride therapy versus placebo in resected colorectal cancer patients who are positive for blood circulating tumor DNA after standard adjuvant therapy (EPOC 1905): ALTAIR trial in CIRCULATE-Japan (trial in progress)

TPS215

Background: Circulating tumor DNA (ctDNA) can be used to predict the risk of recurrence by detecting molecular residual disease (MRD) in patients with colorectal cancer (CRC). Although patients with MRD positive status have extremely high risk of relapse, no standard treatment has been established for these patients after adjuvant chemotherapy. Trifluridine/tipiracil hydrochloride (FTD/TPI) is an oral anti-tumor agent combining thymidine-based nucleoside analogue with a thymidine phosphorylase inhibitor, which presents improved survival in patients with metastatic CRC refractory to fluoropyrimidines. Methods: The ALTAIR trial is a randomized, double-blind, phase III study designed to establish the superiority of FTD/TPI as compared with placebo in patients with resected CRC who show MRD positive status at any time after curative resection. ctDNA testing for screening patients with MRD positive is performed in the observational GALAXY study (UMIN000039205) that is a prospectively conducted large-scale nationwide registry designed to monitor ctDNA status for patient who can undergo curative resection. A personalized tumor-informed assay (Signatera bespoke multiplex-PCR NGS assay) is used for the detection and quantification of ctDNA-based postsurgical MRD. Key eligibility criteria are (a) having undergone radical resection of primary and/or metastatic tumors, (b) a history of standard adjuvant chemotherapy, (c) positive ctDNA status within the previous 3 months at any time postoperatively, and (d) no obvious relapse confirmed by chest, abdominal, and pelvic CT scans. Patients will be randomly assigned in a 1:1 ratio to receive either 6 months of oral FTD/TPI or a matching course of placebo. Randomization is stratified by age (<70 vs. ≥70 years), stage (stage II or lower vs stage III vs. stage IV or M1), primary tumor location (right-sided vs left-sided colon vs rectum), ctDNA status at 1 month (positive vs negative or unmeasurable), and institution. The primary endpoint is disease free survival (DFS). Key secondary endpoints include rate of conversion from positive to negative ctDNA status, overall survival, adverse events, and quality of life. Assuming that the median DFS in the placebo group is approximately 8 months, a total of 240 patients (120 per arm) will provide 80% power to detect an expected DFS hazard ratio of 0.667 at two-sided significance level of 0.05, with an enrollment period of 2 years and a follow-up period of 1 year. This trial is actively accruing across 39 institutions in Japan and Taiwan and opened to recruitment in August 2018. By October 2021, a total of 67 patients have been enrolled. Clinical trial information: JapicCTI-205363/NCT04457297.

Safety and efficacy of encorafenib, binimetinib, plus cetuximab for BRAF V600E-mutant metastatic colorectal cancer: Results of a prospective study as an expanded access program

199

Background: The encorafenib, binimetinib, and cetuximab (triplet) regimen showed survival benefit and a higher response rate over standard chemotherapy among pretreated patients (pts) with BRAF V600E-mutant metastatic colorectal cancer (mCRC) in the phase III BEACON trial. Herein, we report the safety and efficacy of the triplet regimen in a prospective study (JapicCTI-205146) as a Japanese expanded access program (EAP). Methods: The key eligibility criteria were age ≥18 years and a diagnosis of BRAF V600E-mutant mCRC with progression observed after one or two prior systemic chemotherapy. Encorafenib (300 mg QD), binimetinib (45 mg BID), and weekly cetuximab (400 mg/m2, followed by 250 mg/m2) were administered. Patients who had received at least one dose of any study drug were included in this analysis. Adverse events were evaluated using CTCAE v4.0. The objective response rate (ORR) was evaluated using RECIST Guideline Version 1.1. Results: A total of 86 pts were enrolled from 10 Japanese institutions from February to December 2020. Safety and efficacy were evaluated in 81 pts. The median age was 60 years. Fifty-four pts (67%) had ECOG PS 0 and 50 pts (62%) received one prior chemotherapy. Treatment-related serious adverse events and grade 3 or higher treatment-related adverse events were observed in 14 (17%) and 24 (30%) pts, respectively. Treatment-related death occurred in one pts. Among the 76 pts with target lesions, 21 pts were responders, and the confirmed ORR was 27.6%. Stable disease was observed in 42 pts, resulting in a disease control rate of 82.9%. The ORR was consistent regardless of ECOG PS status, the number of prior chemotherapy lines, and the number of metastatic organs. Conclusions: The safety and efficacy of the triplet regimen in the Japanese EAP were comparable to those in the BEACON trial. These results support the triplet regimen as a new standard-of-care treatment option in the second- or third-line treatment of pts with BRAF V600E-mutant mCRC in the Japanese population, as there was a promising response without any new safety signals. Clinical trial information: JapicCTI-205146.

Association of circulating tumor DNA dynamics with clinical outcomes in the adjuvant setting for patients with colorectal cancer from an observational GALAXY study in CIRCULATE-Japan

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Background: Circulating tumor DNA (ctDNA)-based molecular residual disease (MRD) has the potential to select patients who may benefit more from standard-of-care (SOC) adjuvant chemotherapy (ACT) by accurately assessing recurrence-risk post-surgery and by evaluating ACT efficacy. Here we present an analysis from GALAXY study, an observational study monitoring MRD, to evaluating the association of ctDNA dynamics with a short-term clinical outcome and ACT efficacy. Methods: A personalized tumor-informed assay (Signatera bespoke multiplex-PCR NGS assay) was used for post-surgical MRD detection in colorectal cancer (CRC) patients. Six-month disease-free survival (6M-DFS) rates were analyzed excluding patients enrolled in associated phase III trials (VEGA and ALTAIR). Results: Total 1,365 CRC patients enrolled between June 2020 and April 2021 were included in this analysis; 116 pStage I, 478 pStage II, 503 pStage III, and 268 oligomet resectable pStage IV (16% [42/268] received neoadjuvant chemotherapy). 6M-DFS rate by ctDNA dynamics from 4w to 12w were 98% in ‘negative to negative’ group (N = 618), 59% in ‘negative to positive’ (N = 32), 100% in ‘positive to negative’ (N = 58), and 45% in ‘positive to positive’ (N = 78), with a significant difference between ‘positive to negative’ and ‘positive to positive’ groups with hazard ratio (HR) of 52.3 (95% CI: 7.2-380.5; p < 0.001), with a median follow-up time of 6.6 months. Further, out of 188 patients who were MRD+ at 4w with available MRD status at 12w, 95 received SOC ACT (80/95 received fluoropyrimidine [FP] + oxaliplatin and 15 received FP alone) by an investigator’s decision. ctDNA clearance rate at 12w was significantly higher in ACT vs. non-ACT; 57% (54/95) vs. 8% (7/93) in pStage I-IV (p < 0.001), and 58% (42/72) vs. 11% (4/37) in pStage II-III (p < 0.001). In addition, ctDNA clearance rate at 24w was also significantly higher in ACT vs. non-ACT; 26% (7/27) vs. 0% (0/30) in pStage I-IV (p = 0.003), and 33% (7/21) vs. 0% (0/15) in pStage II-III (p = 0.03). Cumulative incidence of ctDNA clearance was significantly higher in ACT vs. non-ACT (67% vs. 7% by 24w; cumulative HR = 17.1; 95% CI: 6.7-43.4, p < 0.001). Among 4w-MRD+ patients, 6M-DFS rate was significantly higher in ACT vs. non-ACT; 84% vs. 34% (HR = 0.15; 95% CI: 0.078-0.25; p < 0.001), which was seen in all stages, including pStage II. Conclusions: This analysis from the GALAXY study, is the largest MRD study to date, demonstrating the association of ctDNA dynamics with improved clinical outcomes in MRD+ patients. Our study shows that stratifying post-surgical treatment decisions using the assay can identify patients likely to benefit from ACT across all stages, including pStage II. ctDNA-guided adjuvant strategy will further be established by ongoing randomized VEGA and ALTAIR studies and will be presented in the future conferences. Clinical trial information: jRCT1031200006.

Efficacy of immune checkpoint inhibitors for gastrointestinal cancers with SWI/SNF complex genetic alterations

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Background: SWI/SNF chromatin-remodeling complex is encoded by multi-gene families that are recurrently mutated in cancer. Previous studies reported that tumors harboring SWI/SNF complex genetic alterations (GA) are sensitive to immune checkpoint inhibitors (ICIs), but the clinical significance of SWI/SNF complex GA in patients with gastrointestinal cancers (GICs) is unclear. Methods: We reviewed patients with metastatic GICs who underwent comprehensive genomic profiling (CGP) and received ICIs at our institution between July 2014–June 2021. SWI/SNF complex GA were defined as ARID1A, ARID1B, ARID2, PBRM1, SMARCA4, and SMARCB1 alterations. Results: Of 292 patients receiving CGP, 136 patients received ICIs, of which 10 (7.4%) had SWI/SNF GA, including 8 ARID1A (5.9%), 1 ARID2 (0.7%) and 2 SMARCA4 (1.5%) alterations. The subjects included 50 esophageal cancers, 84 gastric cancers, and 2 small intestine cancers. The patients with SWI/SNF complex GA had significantly higher proportions of microsatellite instability-high ( p = 0.004) and lower proportions of esophageal cancer ( p = 0.002), compared with patients without SWI/SNF complex GA. During the median follow-up time of 7.5 months (M), the median overall survival (OS), time-to-treatment failure (TTF), and progression-free survival (PFS) in all patients was 13.2 M ([95% confidence interval [CI] 7.7-21.8 M), 2.2 M (95%CI, 1.8-2.5 M), and 2.3 M (95%CI, 1.9-2.8 M), respectively. The patients with SWI/SNF complex GA had better OS (median, not reached vs 10.3 M; hazard ratio [HR], 0.40 [95% confidence interval [CI] 0.19–0.86]; p = 0.019) than those without SWI/SNF complex GA. The patients with SWI/SNF complex GA tended to have longer TTF (median, 4.7 M vs 2.1 M; HR, 0.67 [95%CI 0.38–1.17]; p = 0.16) and PFS (median, 5.4 M vs 2.2 M; HR, 0.70 [95%CI 0.39–1.27], p = 0.24) than those without SWI/SNF GA. The objective response rate (ORR) and disease control rate (DCR) in all patients was 13.2% (95%CI, 8.0-20.1) and 40.4% (95%CI, 32.1-49.2), respectively. The ORR and DCR of patients with SWI/SNF complex GA tended to be higher than those without SWI/SNF complex GA (ORR, 30.0% vs 11.9%; p = 0.13: DCR, 70.0% vs 38.1%; p = 0.09), with 1 complete response and 2 partial responses in the patients with SWI/SNF complex GA. Conclusions: The patients with GICs who had SWI/SNF complex GA were more likely to benefit from ICI therapy, suggesting that novel ICI-containing chemotherapies targeting SWI/SNF complex GA are needed for GICs.[Table: see text]

Exploratory analysis of baseline tumor burden in the TRUSTY study: A randomized phase 2/3 study of trifluridine/tipiracil plus bevacizumab versus irinotecan and fluoropyrimidine plus bevacizumab as second-line treatment in patients with metastatic colorectal cancer

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Background: In primary analysis from the TRUSTY study, trifluridine/tipiracil (FTD/TPI) plus bevacizumab (BEV) failed to show non-inferiority to irinotecan and fluoropyrimidine plus BEV in overall survival (OS) as second-line treatment in patients (pts) with metastatic colorectal cancer (mCRC) (median OS, 14.8 vs. 18.1 months: HR, 1.38: 95% CI; 0.99-1.93: p = 0.59 for non-inferiority; Kuboki Y, et al. ASCO 2021). Here we report a post hoc efficacy analysis by baseline tumor burden. Methods: Pts with histologically confirmed mCRC who failed first-line chemotherapy with fluoropyrimidine and oxaliplatin plus either BEV or an anti-EGFR antibody were eligible. Pts were randomized to receive either FTD/TPI plus BEV (FTD/TPI plus BEV group, FTD/TPI 35 mg/m2 twice daily on days 1–5 and 8–12 every 28-day cycle, and BEV 5 mg/kg on days 1 and 15) or either FOLFIRI or S-1 and irinotecan combined with BEV (control group). Efficacy measured by OS, progression-free survival (PFS), and disease control rate (DCR) were compared between pts grouped by baseline sum of diameter of target lesions (STL). Survival curves were drawn by direct survival estimation adjusted for stratification factors. Results: In the ITT population (N = 396), 60 mm was selected as the optimal cutoff for STL because it produced the most significant difference in OS; 151 pts had high tumor burden with STL ≥ 60 mm (FTD/TPI plus BEV, n = 76: control, n = 75), 216 had low tumor burden with STL < 60 mm (n = 107, n = 109), and 29 were excluded due to no measurable lesions. Baseline characteristics in pts with both high and low tumor burden were balanced between treatment groups. In pts with STL ≥ 60 mm, FTD/TPI plus BEV was less effective than the control: adjusted median OS was 10.9 versus 16.2 months (HR: 2.32; 95% CI: 1.42-3.79), median PFS was 3.5 versus 6.1 months (HR: 2.32; 95% CI: 1.52-3.53): and DCR was 53.9% versus 72.0% (p = 0.03). In pts with STL < 60 mm, FTD/TPI plus BEV was comparably effective to the control: median OS was 21.4 versus 20.7 months (HR: 0.92; 95% CI: 0.55-1.55), median PFS was 5.6 versus 6.0 months (HR: 1.23; 95% CI: 0.87-1.72), and DCR was 66.4% versus 71.6% (p = 0.46). Conclusions: FTD/TPI + BEV might be a second-line treatment option for mCRC pts with low tumor burden (STL < 60 mm). Clinical trial information: jRCTs031180122.