Liver metastases and peritoneal metastases and response to checkpoint inhibitors in metastatic colorectal cancer with microsatellite instability.

BACKGROUND: There have been conflicting reports on the predictive impact of metastatic disease sites on the response to checkpoint inhibitors (CPI) in microsatellite instability (MSI) metastatic colorectal cancers (mCRC). Recent studies have highlighted peritoneal metastases, ascites, and liver metastases as possible indicators of resistance to CPI. METHODS: We performed a detailed analysis of high microsatellite instability (MSI-H) mCRC treated with programmed cell death (PD-1) or PD-1/cytotoxic T-lymphocyte-associated protein 4 CPI in a single center. Overall response rate (ORR), progression-free survival (PFS), overall survival (OS), and stable disease but with complete pathological response upon resection (SDcPR) were analyzed by the presence of liver metastases, peritoneal metastases, or absence of either. The impact of number and size of liver metastases on clinical outcomes were also interrogated. RESULTS: Thirty-five patients with MSI mCRC were included in the analysis. Patients with peritoneal metastatic disease had lower ORR and shorter PFS compared to patients without liver and peritoneal metastases. Contrary to recent reports, ORR and ORR + SDcPR rates were high in patients with liver metastases, at 58% and 66%, respectively. In the liver metastases category, a better response rate was noted for patients with<5 lesions compared to patients with more than 5 lesions. Patients who responded had a higher median tumor mutation burden than patients with progressive disease. CONCLUSIONS: In MSI mCRC, no single clinical characteristic was sufficient to preclude CPI response. Peritoneal metastatic disease was associated with numerically lower ORR and shorter PFS. In contrast, liver metastases do not predict poor outcome.

Clinical Trial Data Review of the Combination FTD/TPI + Bevacizumab in the Treatment Landscape of Unresectable Metastatic Colorectal Cancer.

OPINION STATEMENT: Recommended first and second line treatments for unresectable metastatic colorectal cancer (mCRC) include fluorouracil-based chemotherapy, anti-vascular endothelial growth factor (VEGF)-based therapy, and anti-epidermal growth factor receptor-targeted therapies. In third line, the SUNLIGHT trial showed that trifluridine/tipiracil + bevacizumab (FTD/TPI + BEV) provided significant survival benefits and as such is now a recommended third line regimen in patients with refractory mCRC, irrespective of RAS mutational status and previous anti-VEGF treatment. Some patients are not candidates for intensive combination chemotherapy as first-line therapy due to age, low tumor burden, performance status and/or comorbidities. Capecitabine (CAP) + BEV is recommended in these patients. In the SOLSTICE trial, FTD/TPI + BEV as a first line regimen in patients not eligible for intensive therapy was not superior to CAP + BEV in terms of progression-free survival (PFS). However, in SOLSTICE, FTD/TPI + BEV resulted in similar PFS, overall survival, and maintenance of quality of life as CAP + BEV, with a different safety profile. FTD/TPI + BEV offers a possible first line alternative in patients for whom CAP + BEV is an unsuitable treatment. This narrative review explores and summarizes the clinical trial data on FTD/TPI + BEV.

Impact of PIPAC-Oxaliplatin on Functional Recovery, Good Days, and Survival in a Refractory Colorectal and Appendiceal Carcinomatosis: Secondary Analysis of the US PIPAC Collaborative Phase 1 Trial.

BACKGROUND: Pressurized intraperitoneal aerosolized chemotherapy (PIPAC) is a novel, minimally invasive, safe, and repeatable method to treat carcinomatosis. Evidence regarding the clinical benefit (quality of life and survival) of PIPAC compared with that of conventional standard therapy (ST) is lacking. METHODS: This is the secondary analysis of the phase 1 US-PIPAC trial for refractory colorectal and appendiceal carcinomatosis. A PIPAC cohort was compared with a retrospective cohort of consecutive patients receiving ST. The primary outcome was number of good days (number of days alive and out of the hospital). The secondary outcomes were overall survival (OS), progression-free survival (PFS), health-related quality of life (HRQoL), and objective functional recovery (daily step count). RESULTS: The study included 32 patients (PIPAC, 12; ST, 20) with similar baseline characteristics. Compared with the ST cohort, the PIPAC cohort had lower median inpatient hospital stays (> 24 h) within 6 months (0 vs 1; p = 0.015) and 1 year (1 vs 2; p = 0.052) and higher median good days at 6 months (181 vs 131 days; p = 0.042) and 1 year (323 vs 131 days; p = 0.032). There was no worsening of HRQoL after repeated PIPACs. Step counts diminished immediately after PIPAC but returned to baseline within 2-4 weeks. Kaplan-Meier analysis demonstrated a favorable association between receipt of PIPAC and OS (median, 11.3 vs 5.1 months; p = 0.036). CONCLUSION: Compared with ST, PIPAC was associated with higher number of good days, reduced hospitalization burden, and longer OS without a negative impact on HRQoL with repeated PIPACs. These findings are foundational for evaluation of PIPAC in a randomized clinical trial.

Safety of pressurized intraperitoneal aerosolized chemotherapy in biliary cancer patients with peritoneal metastases.

Biliary tract cancers are a rare diagnosis with a rising incidence. Up to 20% of patients have peritoneal metastases, resulting in symptoms of ascites, abdominal pain and potential bowel obstruction. A standard of care systemic treatment comprises gemcitabine, cisplatin and durvalumab (gem/cis/durva). However, the clinical benefit among patients with peritoneal metastases remains unknown. Pressurized intraperitoneal aerosolized chemotherapy (PIPAC) delivers chemotherapy directly to the peritoneal space, which could potentially improve efficacy with minimal systemic toxicity. We describe the design of a Phase I study investigating PIPAC with nab-paclitaxel plus systemic gem/cis/durva among biliary tract cancer patients with peritoneal metastases who have not received prior systemic treatment. The primary end point is safety of PIPAC with nab-paclitaxel in combination with systemic gem/cis/durva.Clinical Trial Registration: NCT05285358 (ClinicalTrials.gov).

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Clinical Outcomes of Elective Early Discontinuation of Immunotherapy Based on Objective Response in Microsatellite Instability-High Metastatic Colorectal Cancer.

BACKGROUND: Patients with microsatellite-high (MSI-H) metastatic colorectal cancers (CRC) may experience long-lasting benefit from immune checkpoint inhibitors (ICI) upon stopping therapy. However, optimal timing and patient selection criteria for early treatment withdrawal remain undefined. In this single-center retrospective study, we characterized the clinical response and associated survival outcomes of patients who received elective early versus late treatment discontinuation. METHODS: We retrospectively analyzed patients with MSI-H metastatic CRC treated with ICI therapy from May 2015 to April 2024. Early ICI discontinuation was defined as treatment withdrawal before 2 years, and late ICI discontinuation as after 2 years. Response was assessed using Response Evaluation Criteria in Solid Tumors. Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan Meier method. Efficacy outcomes between early and late ICI discontinuation groups were compared using a log-rank test. RESULTS: Of 36 patients with MSI-H metastatic CRC, 12 underwent elective early ICI discontinuation and 9 experienced late ICI discontinuation. After a median follow-up of 32 months post-treatment, 91.7% (11/12) in the early discontinuation group remain off therapy without progression. PFS and OS outcomes between the early and late discontinuation groups were similarly favorable (P = .88 and P = .85, respectively), despite a 12-month difference in median duration of ICI therapy (13.3 and 25.6 months, respectively). The most common reason for elective early treatment discontinuation was clinical remission (n = 10), defined as a complete response, or a partial response with negative PET and/or ctDNA testing. CONCLUSIONS: Early ICI discontinuation guided by response criteria resulted in low rates of recurrence. Survival outcomes between early and late ICI discontinuation groups were comparable, suggesting that treatment duration can be individualized based on clinical response without compromising favorable long-term prognosis.

Plain language summary of SUNLIGHT: trifluridine/tipiracil and bevacizumab for refractory metastatic colorectal cancer.

WHAT IS THIS SUMMARY ABOUT?: This is a summary describing the results from a phase 3 clinical trial called SUNLIGHT. The study looked at treatment with orally administered trifluridine/tipiracil plus intravenously administered bevacizumab in people with metastatic colorectal cancer (mCRC) that is refractory to treatment.This study included people whose cancer had grown or spread beyond its original location after no more than two previous treatments. People in the study received either the combination of trifluridine/tipiracil plus bevacizumab or they received trifluridine/tipiracil alone. The aims of the study were to see how long people lived after treatment with trifluridine/tipiracil plus bevacizumab compared with trifluridine/tipiracil alone and to find out how well the combination of trifluridine/tipiracil plus bevacizumab worked at slowing down the spread of the cancer. Researchers also looked at side effects from taking the medicines and at how treatment affected people's physical functioning. WHAT ARE THE KEY TAKEAWAYS?: People in the combination group lived longer (a median of 10.8 months) than people who received trifluridine/tipiracil alone (7.5 months). In addition, the time it took for the cancer to worsen was longer for those who received the combination treatment (a median of 5.6 months) compared with those who received trifluridine/tipiracil alone (2.4 months). People's physical functioning took longer to worsen with combination therapy (a median of 9.3 months) than it did with trifluridine/tipiracil alone (6.3 months), as measured by the impact of treatment on people's ability to carry out daily living activities. The most common side effects in both treatment groups were low levels of white blood cells, known as neutrophils (neutropenia), nausea, and low levels of healthy red blood cells (anemia). WHAT WERE THE MAIN CONCLUSIONS REPORTED BY THE RESEARCHERS?: The results from the study suggest that treatment with oral trifluridine/tipiracil plus intravenous (IV) bevacizumab could help people with refractory mCRC live longer and maintain good physical functioning, and it could slow the worsening of their cancer.Clinical Trial Registration: NCT04737187 (SUNLIGHT) (ClinicalTrials.gov).

Botensilimab plus balstilimab in relapsed/refractory microsatellite stable metastatic colorectal cancer: a phase 1 trial.

Microsatellite stable metastatic colorectal cancer (MSS mCRC; mismatch repair proficient) has previously responded poorly to immune checkpoint blockade. Botensilimab (BOT) is an Fc-enhanced multifunctional anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) antibody designed to expand therapy to cold/poorly immunogenic solid tumors, such as MSS mCRC. BOT with or without balstilimab (BAL; anti-PD-1 antibody) is being evaluated in an ongoing expanded phase 1 study. The primary endpoint is safety and tolerability, which was evaluated separately in the dose-escalation portion of the study and in patients with MSS mCRC (using combined dose-escalation/dose-expansion data). Secondary endpoints include investigator-assessed RECIST version 1.1-confirmed objective response rate (ORR), disease control rate (DCR), duration of response (DOR) and progression-free survival (PFS). Here we present outcomes in 148 heavily pre-treated patients with MSS mCRC (six from the dose-escalation cohort; 142 from the dose-expansion cohort) treated with BOT and BAL, 101 of whom were considered response evaluable with at least 6 months of follow-up. Treatment-related adverse events (TRAEs) occurred in 89% of patients with MSS mCRC (131/148), most commonly fatigue (35%, 52/148), diarrhea (32%, 47/148) and pyrexia (24%, 36/148), with no grade 5 TRAEs reported and a 12% discontinuation rate due to a TRAE (18/148; data fully mature). In the response-evaluable population (n = 101), ORR was 17% (17/101; 95% confidence interval (CI), 10-26%), and DCR was 61% (62/101; 95% CI, 51-71%). Median DOR was not reached (NR; 95% CI, 5.7 months-NR), and median PFS was 3.5 months (95% CI, 2.7-4.1 months), at a median follow-up of 10.3 months (range, 0.5-42.6 months; data continuing to mature). The combination of BOT plus BAL demonstrated a manageable safety profile with no new immune-mediated safety signals and encouraging clinical activity with durable responses. ClinicalTrials.gov identifier: NCT03860272 .

KRAS G12C Inhibitors in the Treatment of Metastatic Colorectal Cancer.

KRAS mutations contribute substantially to the overall colorectal cancer burden and have long been a focus of drug development efforts. After a lengthy preclinical road, KRAS inhibition via the G12C allele has finally become a therapeutic reality. Unlike in NSCLC, early studies of KRAS inhibitors in CRC struggled to demonstrate single agent activity. Investigation into these tissue-specific treatment differences has led to a deeper understanding of the complexities of MAPK signaling and the diverse adaptive feedback responses to KRAS inhibition. EGFR reactivation has emerged as a principal resistance mechanism to KRAS inhibitor monotherapy. Thus, the field has pivoted to dual EGFR/KRAS blockade with promising efficacy. Despite significant strides in the treatment of KRAS G12C mutated CRC, new challenges are on the horizon. Alternative RTK reactivation and countless acquired molecular resistance mechanisms have shifted the treatment goalpost. This review focuses on the historical and contemporary clinical strategies of targeting KRAS G12C alterations in CRC and highlights future directions to overcome treatment challenges.

Multidisciplinary Delphi Consensus on Safety of Combining Transarterial Radioembolization with Yttrium-90 Microspheres with Systemic Anticancer Agents for the Treatment of Liver Malignancy.

PURPOSE: To provide guidance, via multidisciplinary consensus statements, on the safety interactions between systemic anticancer agents (such as radiosensitizing chemotherapy, immunotherapy, targeted therapy, and peptide receptor radionuclide therapy) and transarterial radioembolization (TARE) with yttrium-90 (90Y)-labeled microspheres in the treatment of primary and metastatic liver malignancies. MATERIALS AND METHODS: A literature search identified 59 references that informed 26 statements on the safety of 90Y TARE combined with systemic therapies. Modified Delphi method was used to develop consensus on statements through online anonymous surveys of the 12 panel members representing the fields of interventional radiology, medical oncology, surgical oncology, hepatology, and pharmacy, focusing on hepatocellular carcinoma (HCC), metastatic colorectal cancer (mCRC), neuroendocrine tumors, metastatic breast cancer, and intrahepatic cholangiocarcinoma. RESULTS: High-level evidence was limited. Level 1 data in patients with mCRC suggest that some radiosensitizing chemotherapies (eg, oxaliplatin) require temporary dose reduction when used concomitantly with 90Y TARE, and some targeted therapies (eg, vascular endothelial growth factor inhibitors and antiangiogenic tyrosine kinase inhibitors) should be avoided for at least 4 weeks before 90Y TARE. In patients with HCC, the feasibility of 90Y TARE and immunotherapy has been demonstrated with Level 4 evidence. Data are more limited for other primary and secondary liver malignancies, and consensus statements were driven by expert opinion (Level 5). CONCLUSIONS: Given the absence of evidence-based guidelines on the safety of 90Y TARE in combination with systemic anticancer therapy, these consensus statements provide expert guidance on the potential risks when considering specific combinations.

Pembrolizumab Plus mFOLFOX7 or FOLFIRI for Microsatellite Stable/Mismatch Repair-Proficient Metastatic Colorectal Cancer: KEYNOTE-651 Cohorts B and D.

BACKGROUND: The phase 1b KEYNOTE-651 study evaluated pembrolizumab plus chemotherapy in microsatellite stable or mismatch repair-proficient metastatic colorectal cancer. PATIENTS AND METHODS: Patients with microsatellite stable or mismatch repair-proficient metastatic colorectal cancer received pembrolizumab 200 mg every 3 weeks plus 5-fluorouracil, leucovorin, oxaliplatin (previously untreated; cohort B) or 5-fluorouracil, leucovorin, irinotecan (previously treated with fluoropyrimidine plus oxaliplatin; cohort D) every 2 weeks. Primary end point was safety; investigator-assessed objective response rate per RECIST v1.1 was secondary and biomarker analysis was exploratory. RESULTS: Thirty-one patients were enrolled in cohort B and 32 in cohort D; median follow-up was 30.2 and 33.5 months, respectively. One dose-limiting toxicity (grade 3 small intestine obstruction) occurred in cohort D. In cohort B, grade 3 or 4 treatment-related adverse events (AEs) occurred in 18 patients (58%), most commonly neutropenia and decreased neutrophil count (n = 5 each). In cohort D, grade 3 or 4 treatment-related AEs occurred in 17 patients (53%), most commonly neutropenia (n = 7). No grade 5 treatment-related AEs occurred. Objective response rate was 61% in cohort B (KRAS wildtype: 71%; KRAS mutant: 53%) and 25% in cohort D (KRAS wildtype: 47%; KRAS mutant: 6%). In both cohorts, PD-L1 combined positive score and T-cell-inflamed gene expression profiles were higher and HER2 expression was lower in responders than nonresponders. No association between tumor mutational burden and response was observed. CONCLUSION: Pembrolizumab plus 5-fluorouracil, leucovorin, oxaliplatin/5-fluorouracil, leucovorin, irinotecan demonstrated an acceptable AE profile. Efficacy data appeared comparable with current standard of care (including by KRAS mutation status). Biomarker analyses were hypothesis-generating, warranting further exploration. GOV IDENTIFIER: ClinicalTrials.gov; NCT03374254.

A phase I/II study of nintedanib and capecitabine for refractory metastatic colorectal cancer.

BACKGROUND: Nintedanib is a tyrosine kinase inhibitor with efficacy in bevacizumab-resistant colorectal cancer models. This phase I/II study evaluated the recommended phase II dose and efficacy of nintedanib and capecitabine in refractory metastatic colorectal cancer. METHODS: Key eligibility criteria included refractory metastatic colorectal cancer and ECOG performance status of 1 or lower. The primary endpoint was 18-week progression-free survival (PFS). A 1-sided binomial test (at α = .1) compared the observed 18-week PFS with a historic control of .25. RESULTS: Forty-two patients were enrolled, including 39 at the recommended phase II dose. The recommended phase II dose was established to be nintedanib 200 mg by mouth twice daily and capecitabine 1000 mg/m2 by mouth twice daily. The protocol was evaluated for efficacy in 36 patients. The 18-week PFS was 42% (15/36 patients; P = .0209). Median PFS was 3.4 mo. Median overall survival was 8.9 mo. Sixteen (44%) patients experienced a grade 3/4 adverse event, most commonly fatigue (8%), palmoplantar erythrodysesthesia (8%), aspartate aminotransferase elevation (6%), asthenia (6%), pulmonary embolus (6%), and dehydration (6%). Osteopontin levels at cycle 1, day 1 and cycle 3, day 1 as well as ΔCCL2 levels correlated to disease control at 18 weeks. CONCLUSIONS: The combination of nintedanib and capecitabine is well tolerated. Clinical efficacy appears to be superior to regorafenib or tipiracil hydrochloride monotherapy. Further investigation of similar combinations is warranted. CLINICALTRIALS.GOV IDENTIFIER: NCT02393755.

Outcome prioritization and preferences among older adults with cancer starting chemotherapy in a randomized clinical trial.

INTRODUCTION: Older adults with cancer facing competing treatments must prioritize between various outcomes. This study assessed health outcome prioritization among older adults with cancer starting chemotherapy. METHODS: Secondary analysis of a randomized trial addressing vulnerabilities in older adults with cancer. Patients completed three validated outcome prioritization tools: 1) Health Outcomes Tool: prioritizes outcomes (survival, independence, symptoms) using a visual analog scale; 2) Now vs. Later Tool: rates the importance of quality of life at three times-today versus 1 or 5 years in the future; and 3) Attitude Scale: rates agreement with outcome-related statements. The authors measured the proportion of patients prioritizing various outcomes and evaluated their characteristics. RESULTS: A total of 219 patients (median [range] age 71 [65-88], 68% with metastatic disease) were included. On the Health Outcomes Tool, 60.7% prioritized survival over other outcomes. Having localized disease was associated with choosing survival as top priority. On the Now vs. Later Tool, 50% gave equal importance to current versus future quality of life. On the Attitude Scale, 53.4% disagreed with the statement "the most important thing to me is living as long as I can, no matter what my quality of life is"; and 82.2% agreed with the statement "it is more important to me to maintain my thinking ability than to live as long as possible". CONCLUSION: Although survival was the top priority for most participants, some older individuals with cancer prioritize other outcomes, such as cognition and function. Clinicians should elicit patient-defined priorities and include them in decision-making.

Pembrolizumab Plus Binimetinib With or Without Chemotherapy for MSS/pMMR Metastatic Colorectal Cancer: Outcomes From KEYNOTE-651 Cohorts A, C, and E.

BACKGROUND: Cohorts A, C, and E of the phase Ib KEYNOTE-651 study evaluated pembrolizumab + binimetinib ± chemotherapy in microsatellite stable/mismatch repair-proficient metastatic colorectal cancer. PATIENTS AND METHODS: Patients received pembrolizumab 200 mg every 3 weeks plus binimetinib 30 mg twice daily alone (cohort A; previously treated with any chemotherapy) or with 5-fluorouracil, leucovorin, oxaliplatin (cohort C; previously untreated) or 5-fluorouracil, leucovorin, irinotecan (cohort E; previously treated with 1 line of therapy including fluoropyrimidine + oxaliplatin-based regimen) every 2 weeks. Binimetinib dose-escalation to 45 mg twice daily was planned in all cohorts using a modified toxicity probability interval design (target dose-limiting toxicity [DLT], 30%). The primary endpoint was safety; investigator-assessed objective response rate was secondary. RESULTS: In cohort A, 1/6 patients (17%) had DLTs with binimetinib 30 mg; none occurred in 14 patients with 45 mg. In cohort C, 3/9 patients (33%) had DLTs with binimetinib 30 mg; dose was not escalated to 45 mg. In cohort E, 1/5 patients (20%) had DLTs with binimetinib 30 mg; 5/10 patients (50%) had DLTs with 45 mg. Enrollment was stopped in cohort E binimetinib 45 mg and deescalated to 30 mg; 2/4 additional patients (50%) had DLTs with binimetinib 30 mg (total 3/9 [33%] had DLTs with binimetinib 30 mg). Objective response rate was 0% in cohort A, 9% in cohort C, and 15% in cohort E. CONCLUSION: Per DLT criteria, binimetinib + pembrolizumab (cohort A) was tolerable, binimetinib + pembrolizumab + 5-fluorouracil, leucovorin, oxaliplatin (cohort C) did not qualify for binimetinib dose escalation to 45 mg, and binimetinib + pembrolizumab + 5-fluorouracil, leucovorin, irinotecan (cohort E) required binimetinib dose reduction from 45 to 30 mg. No new safety findings were observed across cohorts. There was no apparent additive efficacy when binimetinib + pembrolizumab was added to chemotherapy. Data did not support continued enrollment in cohorts C and E.

Recurrence patterns after complex multimodality therapy and hepatic arterial infusion for colorectal liver metastases: A reflection of biology and technique.

BACKGROUND AND METHODS: We characterized colorectal liver metastasis recurrence and survival patterns after surgical resection and intraoperative ablation ± hepatic arterial infusion pump (HAIP) placement. We estimated patterns of recurrence and survival in patients undergoing contemporary multimodal treatments. Between 2017 and 2021, patient, tumor characteristics, and recurrence data were collected. Primary outcomes included recurrence patterns and survival data based on operative intervention. RESULTS: There were 184 patients who underwent hepatectomy and intraoperative ablation. Sixty patients (32.6%) underwent HAIP placement. A total of 513 metastases were ablated, median total of 2 ablations per patient. Median time to recurrence was 31 [22-40] months. Recurrence patterns included tumor at ablative margin on first scheduled postoperative imaging (8, 4.3%), local tumor recurrence at ablative site (69, 37.5%), and non-ablated liver tumor recurrence (38, 20.6%). In patients who underwent HAIP placement, the rate of liver recurrence was reduced (45% vs 70.9%, p = 0.0001). Median overall survival was 64 [41-58] months and prolonged survival was associated with HAIP treatment (85 [66-109] vs 60 [51-70] months. CONCLUSIONS AND DISCUSSION: Hepatic recurrence is common and combination of intraoperative ablation and HAIP treatments were associated with prolonged survival. These data may reflect patient selection however, future work will clarify preoperative tumor and patient characteristics that may better predict recurrence expectations.

Efficacy and Safety of Trifluridine/Tipiracil-Containing Combinations in Colorectal Cancer and Other Advanced Solid Tumors: A Systematic Review.

We performed a systematic literature review to identify and summarize data from studies reporting clinical efficacy and safety outcomes for trifluridine/tipiracil (FTD/TPI) combined with other antineoplastic agents in advanced cancers, including metastatic colorectal cancer (mCRC). We conducted a systematic search on May 29, 2021, for studies reporting one or more efficacy or safety outcome with FTD/TPI-containing combinations. Our search yielded 1378 publications, with 38 records meeting selection criteria: 35 studies of FTD/TPI-containing combinations in mCRC (31 studies second line or later) and 3 studies in other tumor types. FTD/TPI plus bevacizumab was extensively studied, including 19 studies in chemorefractory mCRC. Median overall survival ranged 8.6-14.4 months and median progression-free survival 3.7-6.8 months with FTD/TPI plus bevacizumab in refractory mCRC. Based on one randomized and several retrospective studies, FTD/TPI plus bevacizumab was associated with improved outcomes compared with FTD/TPI monotherapy. FTD/TPI combinations with chemotherapy or other targeted agents were reported in small early-phase studies; preliminary data indicated higher antitumor activity for certain combinations. Overall, no safety concerns existed with FTD/TPI combinations; most common grade ≥ 3 adverse event was neutropenia, ranging 5%-100% across all studies. In studies comparing FTD/TPI combinations with monotherapy, grade ≥ 3 neutropenia appeared more frequently with combinations (29%-67%) vs. monotherapy (5%-41%). Discontinuation rates due to adverse events ranged 0%-11% for FTD/TPI plus bevacizumab and 0%-17% with other combinations. This systematic review supports feasibility and safety of FTD/TPI plus bevacizumab in refractory mCRC. Data on non-bevacizumab FTD/TPI combinations remain preliminary and need further validation.

Sotorasib with panitumumab in chemotherapy-refractory KRASG12C-mutated colorectal cancer: a phase 1b trial.

The current third-line (and beyond) treatment options for RAS-mutant metastatic colorectal cancer have yielded limited efficacy. At the time of study start, the combination of sotorasib, a KRAS (Kirsten rat sarcoma viral oncogene homolog)-G12C inhibitor, and panitumumab, an epidermal growth factor receptor (EGFR) inhibitor, was hypothesized to overcome treatment-induced resistance. This phase 1b substudy of the CodeBreaK 101 master protocol evaluated sotorasib plus panitumumab in patients with chemotherapy-refractory KRASG12C-mutated metastatic colorectal cancer. Here, we report the results in a dose-exploration cohort and a dose-expansion cohort. Patients received sotorasib (960 mg, once daily) plus panitumumab (6 mg kg-1, once every 2 weeks). The primary endpoints were safety and tolerability. Secondary endpoints included efficacy and pharmacokinetics. Exploratory biomarkers at baseline were assessed. Forty-eight patients (dose-exploration cohort, n = 8; dose-expansion cohort, n = 40) were treated. Treatment-related adverse events of any grade and grade ≥3 occurred in 45 (94%) and 13 (27%) patients, respectively. In the dose-expansion cohort, the confirmed objective response rate was 30.0% (95% confidence interval (CI) 16.6%, 46.5%). Median progression-free survival was 5.7 months (95% CI 4.2, 7.7 months). Median overall survival was 15.2 months (95% CI 12.5 months, not estimable). Prevalent genomic coalterations included APC (84%), TP53 (74%), SMAD4 (33%), PIK3CA (28%) and EGFR (26%). Sotorasib-panitumumab demonstrated acceptable safety with promising efficacy in chemotherapy-refractory KRASG12C-mutated metastatic colorectal cancer. ClinicalTrials.gov identifier: NCT04185883 .

Immunotherapy response in microsatellite stable metastatic colorectal cancer is influenced by site of metastases.

BACKGROUND: Prior studies indicate that colorectal cancer patients with liver metastases did not benefit from regorafenib, nivolumab (REGONIVO) or regorafenib, ipilimumab, nivolumab (RIN) treatments, while those without liver metastases showed significant response. This study explores the impact of metastatic sites on treatment outcomes. METHODS: Chemotherapy-refractory colorectal cancer patients treated with REGONIVO or RIN were evaluated, focusing on 2-month organ-specific response, ORR, PFS and OS based on metastatic sites. RESULTS: Of the 96 patients analyzed (58 REGONIVO, 38 RIN), liver or peritoneal metastases led to poor outcomes, with 0 % ORR, and median PFS of 2.0 and 1.5 months respectively. In contrast, lung-only metastases had an ORR of 56.3 % and a PFS of 14 months. The presence of concurrent LN or other extrahepatic metastatic disease in patients with lung metastatic disease diminished but did not prohibit responses. The 2-month response assessment revealed activity in the lungs, soft tissues, and distant lymph nodes. CONCLUSIONS: REGONIVO and RIN were most active in lung-only metastases. Liver and peritoneal metastases were resistant. Future checkpoint inhibitor trials in MSS colorectal cancer should stratify patients based on metastatic locations.

Acquired resistance to KRAS G12C small-molecule inhibitors via genetic/nongenetic mechanisms in lung cancer.

Inherent or acquired resistance to sotorasib poses a substantialt challenge for NSCLC treatment. Here, we demonstrate that acquired resistance to sotorasib in isogenic cells correlated with increased expression of integrin ß4 (ITGB4), a component of the focal adhesion complex. Silencing ITGB4 in tolerant cells improved sotorasib sensitivity, while overexpressing ITGB4 enhanced tolerance to sotorasib by supporting AKT-mTOR bypass signaling. Chronic treatment with sotorasib induced WNT expression and activated the WNT/ß-catenin signaling pathway. Thus, silencing both ITGB4 and ß-catenin significantly improved sotorasib sensitivity in tolerant, acquired, and inherently resistant cells. In addition, the proteasome inhibitor carfilzomib (CFZ) exhibited synergism with sotorasib by down-regulating ITGB4 and ß-catenin expression. Furthermore, adagrasib phenocopies the combination effect of sotorasib and CFZ by suppressing KRAS activity and inhibiting cell cycle progression in inherently resistant cells. Overall, our findings unveil previously unrecognized nongenetic mechanisms underlying resistance to sotorasib and propose a promising treatment strategy to overcome resistance.

Sotorasib plus Panitumumab in Refractory Colorectal Cancer with Mutated KRAS G12C.

BACKGROUND: KRAS G12C is a mutation that occurs in approximately 3 to 4% of patients with metastatic colorectal cancer. Monotherapy with KRAS G12C inhibitors has yielded only modest efficacy. Combining the KRAS G12C inhibitor sotorasib with panitumumab, an epidermal growth factor receptor (EGFR) inhibitor, may be an effective strategy. METHODS: In this phase 3, multicenter, open-label, randomized trial, we assigned patients with chemorefractory metastatic colorectal cancer with mutated KRAS G12C who had not received previous treatment with a KRAS G12C inhibitor to receive sotorasib at a dose of 960 mg once daily plus panitumumab (53 patients), sotorasib at a dose of 240 mg once daily plus panitumumab (53 patients), or the investigator's choice of trifluridine-tipiracil or regorafenib (standard care; 54 patients). The primary end point was progression-free survival as assessed by blinded independent central review according to the Response Evaluation Criteria in Solid Tumors, version 1.1. Key secondary end points were overall survival and objective response. RESULTS: After a median follow-up of 7.8 months (range, 0.1 to 13.9), the median progression-free survival was 5.6 months (95% confidence interval [CI], 4.2 to 6.3) and 3.9 months (95% CI, 3.7 to 5.8) in the 960-mg sotorasib-panitumumab and 240-mg sotorasib-panitumumab groups, respectively, as compared with 2.2 months (95% CI, 1.9 to 3.9) in the standard-care group. The hazard ratio for disease progression or death in the 960-mg sotorasib-panitumumab group as compared with the standard-care group was 0.49 (95% CI, 0.30 to 0.80; P = 0.006), and the hazard ratio in the 240-mg sotorasib-panitumumab group was 0.58 (95% CI, 0.36 to 0.93; P = 0.03). Overall survival data are maturing. The objective response was 26.4% (95% CI, 15.3 to 40.3), 5.7% (95% CI, 1.2 to 15.7), and 0% (95% CI, 0.0 to 6.6) in the 960-mg sotorasib-panitumumab, 240-mg sotorasib-panitumumab, and standard-care groups, respectively. Treatment-related adverse events of grade 3 or higher occurred in 35.8%, 30.2%, and 43.1% of patients, respectively. Skin-related toxic effects and hypomagnesemia were the most common adverse events observed with sotorasib-panitumumab. CONCLUSIONS: In this phase 3 trial of a KRAS G12C inhibitor plus an EGFR inhibitor in patients with chemorefractory metastatic colorectal cancer, both doses of sotorasib in combination with panitumumab resulted in longer progression-free survival than standard treatment. Toxic effects were as expected for either agent alone and resulted in few discontinuations of treatment. (Funded by Amgen; CodeBreaK 300 ClinicalTrials.gov number, NCT05198934.).