Adagrasib with or without Cetuximab in Colorectal Cancer with Mutated KRAS G12C.

BACKGROUND: Adagrasib, an oral small-molecule inhibitor of mutant KRAS G12C protein, has shown clinical activity in pretreated patients with several tumor types, including colorectal cancer. Preclinical studies suggest that combining a KRAS G12C inhibitor with an epidermal growth factor receptor antibody could be an effective clinical strategy. METHODS: In this phase 1-2, open-label, nonrandomized clinical trial, we assigned heavily pretreated patients with metastatic colorectal cancer with mutant KRAS G12C to receive adagrasib monotherapy (600 mg orally twice daily) or adagrasib (at the same dose) in combination with intravenous cetuximab once a week (with an initial loading dose of 400 mg per square meter of body-surface area, followed by a dose of 250 mg per square meter) or every 2 weeks (with a dose of 500 mg per square meter). The primary end points were objective response (complete or partial response) and safety. RESULTS: As of June 16, 2022, a total of 44 patients had received adagrasib, and 32 had received combination therapy with adagrasib and cetuximab, with a median follow-up of 20.1 months and 17.5 months, respectively. In the monotherapy group (43 evaluable patients), a response was reported in 19% of the patients (95% confidence interval [CI], 8 to 33). The median response duration was 4.3 months (95% CI, 2.3 to 8.3), and the median progression-free survival was 5.6 months (95% CI, 4.1 to 8.3). In the combination-therapy group (28 evaluable patients), the response was 46% (95% CI, 28 to 66). The median response duration was 7.6 months (95% CI, 5.7 to not estimable), and the median progression-free survival was 6.9 months (95% CI, 5.4 to 8.1). The percentage of grade 3 or 4 treatment-related adverse events was 34% in the monotherapy group and 16% in the combination-therapy group. No grade 5 adverse events were observed. CONCLUSIONS: Adagrasib had antitumor activity in heavily pretreated patients with metastatic colorectal cancer with mutant KRAS G12C, both as oral monotherapy and in combination with cetuximab. The median response duration was more than 6 months in the combination-therapy group. Reversible adverse events were common in the two groups. (Funded by Mirati Therapeutics; KRYSTAL-1 ClinicalTrials.gov number, NCT03785249.).

A comprehensive analysis of POLE/POLD1 genomic alterations in colorectal cancer.

INTRODUCTION: Pathogenic mutations in POLE/POLD1 lead to decreased fidelity of DNA replication, resulting in a high tumor mutational burden (TMB-H), defined as TMB ≥ 10 mut/Mb, independent of deficient mismatch repair (dMMR) and microsatellite instability high (MSI-H) status. METHODS: De-identified records of patients with colorectal cancer (CRC) profiled with the Tempus xT assay (DNA-seq of 595-648 genes at 500×) were identified from the Tempus Database. RESULTS: Among 9136 CRC samples profiled, the frequency of POLE/POLD1 genomic alterations was 2.4% (n = 217). Copy number loss was the most common genomic alteration (64%, n = 138) of POLE/POLD1, followed by copy number amplifications (18%, n = 40) and short variant mutations (18%, n = 39). The POLE/POLD1 mutated group presented with a higher frequency of TMB-H phenotype relative to wild type (WT; 22% vs. 9%, P < .001), with a median TMB of 127 mut/Mb in the TMB-H POLE/POLD1 subset. The TMB showed a dramatic contrast between POLE/POLD1 short variant mutations as compared to the group with copy number alterations, with a TMB of 159 mut/Mb vs 15 mut/Mb, respectively. Thus, the short variant mutations represented the so-called ultra-hypermutated phenotype. The POLE/POLD1 mutated group, as compared to WT, exhibited a higher rate of coexisting mutations, including APC, ALK, ATM, BRCA2, and RET mutations. CONCLUSION: Patients with POLE/POLD1 mutations exhibited significant differences across immunological markers (ie, TMB, MMR, and MSI-H) and molecular co-alterations. Those with short variant mutations represented 18% of the POLE/POLD1 cohort and 0.4% of the total cohort examined. This group of patients had a median TMB of 159 mut/Mb (range 34-488), representing the ultra-hypermutated phenotype. This group of patients is important to identify given the potential for exceptional response to immune checkpoint inhibitors.

A study to learn how well tucatinib plus trastuzumab works for treating participants with metastatic colorectal cancer, and how safe it is: a plain language summary of the MOUNTAINEER study.

WHAT IS THIS SUMMARY ABOUT?: This is a summary of an article describing an ongoing study called MOUNTAINEER. This article was published in The Lancet Oncology in 2023. The study included 117 adults with metastatic HER2-positive colorectal cancer. The researchers wanted to know whether a combination of 2 drugs called tucatinib and trastuzumab could shrink the participants' cancer. The researchers also wanted to know whether receiving tucatinib alone could also shrink the participants' cancer. WHAT WERE THE RESULTS?: In this study, researchers found that 32 out of 84 participants had their tumors respond to treatment with tucatinib with trastuzumab. This was about 4 in 10 participants. This means that the tumors shrank by at least 30% or disappeared. Participants whose tumors responded to tucatinib with trastuzumab responded for a median of 12.4 months. 60 out of 84 participants had their tumors respond or remain about the same size after treatment with tucatinib with trastuzumab. This was about 7 in 10 participants. For those who received tucatinib with trastuzumab the median length of time participants lived during the study was 24.1 months and the median length of time participants lived during the study without their cancer growing or spreading was 8.2 months. 1 out of 30 participants had their tumors respond to treatment with tucatinib alone within 12 weeks. 19 out of 86 participants who received tucatinib with trastuzumab had serious medical problems, also called serious adverse events. This was about 2 in 10 participants. Not all of these serious adverse events were related to tucatinib with trastuzumab. 3 out of 30 participants who received tucatinib alone who had serious adverse events. This was 1 in 10 participants. Not all of these serious adverse events were related to tucatinib alone. WHAT DO THE RESULTS MEAN?: Tucatinib with trastuzumab could be a good treatment option for people with HER2-positive colorectal cancer that has spread to other parts of the body. On January 19, the Food and Drug Administration (FDA) granted accelerated approval to the combination of two targeted drugs, tucatinib (Tukysa) and trastuzumab (Herceptin) for people with HER2-positive colorectal cancer that is metastatic or that cannot be treated with surgery. The FDA can grant accelerated approval for new treatments that fill unmet needs for patients with serious medical conditions. Clinical Trial Registration: NCT03043313 (MOUNTAINEER study) (ClinicalTrials.gov).

Improving survival in metastatic colorectal cancer through optimized patient selection.

The systemic treatment options for patients with metastatic colorectal cancer have recently expanded with the US Food and Drug Administration approval of fruquintinib being added to previously approved trifluridine/tipiracil with or without bevacizumab and regorafenib. These therapies are recommended for use based on the initial clinical trials that focused on their safety and efficacy in extending overall survival of patients with refractory metastatic disease, as well as later studies, including the ReDOS study that confirmed the dose-escalation strategy of regorafenib to be key in optimizing duration of therapy and preventing side effects. Although more research is needed on how to sequence third-line therapies, data from real-world studies showed that switching from regorafenib to trifluridine/tipiracil with or without bevacizumab allowed patients to have a chemotherapy-free break and led to improved survival, suggesting that there may be a benefit for using regorafenib first. Current treatment guidelines state that each therapy can be given before or after the others. Generally, sequencing considerations in the refractory setting include multiple variables such as tumor characteristics, toxicities, factors that are important to the patient, response to prior lines of therapy, and extent of disease.

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

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

Impact of Anti-EGFR Therapies on HER2-Positive Metastatic Colorectal Cancer: A Systematic Literature Review and Meta-Analysis of Clinical Outcomes.

BACKGROUND: HER2 overexpression/amplification in patients with RAS wild-type (WT) metastatic colorectal cancer (mCRC) may be associated with resistance to standard-of-care anti-EGFR therapies. Given the lack of comprehensive investigations into this association, we assessed the prognostic or predictive effect of HER2 amplification/overexpression on anti-EGFR treatment outcomes. METHODS: A systematic review of MEDLINE, Embase, and Cochrane Library (2001-2021) identified studies evaluating progression-free survival (PFS), overall response rate (ORR), and overall survival (OS) in HER2-positive vs. HER2-negative patients with RAS WT mCRC who received anti-EGFR treatments and whose HER2 status was known. Meta-analyses of proportions (ORR) and hazard ratios (PFS, OS) were performed using random-effect models with pre-specified sensitivity analyses. RESULTS: Five high-quality retrospective cohort studies were included in the meta-analyses representing 594 patients with mCRC. All patients received anti-EGFR treatment, either as monotherapy or in combination with chemotherapy. Meta-analysis of PFS demonstrated a 2.84-fold higher risk of death or progression (95% CI, 1.44-5.60) in patients with HER2-positive (vs. HER2-negative) RAS WT mCRC treated with anti-EGFR regimens. The odds of response to anti-EGFR treatment were 2-fold higher in HER2-negative vs. HER2-positive (odds ratio, 1.96 [95% CI, 1.10-3.48]). Differences in OS were not statistically significant. Sensitivity analyses confirmed the robustness of the base-case estimates. CONCLUSIONS: While this study could not account for all confounding factors, in patients with RAS WT mCRC who received anti-EGFR therapy, HER2 overexpression/amplification was associated with worse PFS and ORR and may therefore predict poorer outcomes. HER2 testing is important to inform treatment decisions and could optimize outcomes for patients.

Synergistic combination of cytotoxic chemotherapy and cyclin-dependent kinase 4/6 inhibitors in biliary tract cancers.

BACKGROUND AND AIMS: Biliary tract cancers (BTCs) are uncommon, but highly lethal, gastrointestinal malignancies. Gemcitabine/cisplatin is a standard-of-care systemic therapy, but has a modest impact on survival and harbors toxicities, including myelosuppression, nephropathy, neuropathy, and ototoxicity. Whereas BTCs are characterized by aberrations activating the cyclinD1/cyclin-dependent kinase (CDK)4/6/CDK inhibitor 2a/retinoblastoma pathway, clinical use of CDK4/6 inhibitors as monotherapy is limited by lack of validated biomarkers, diffident preclinical efficacy, and development of acquired drug resistance. Emerging studies have explored therapeutic strategies to enhance the antitumor efficacy of CDK4/6 inhibitors by the combination with chemotherapy regimens, but their mechanism of action remains elusive. APPROACH AND RESULTS: Here, we report in vitro and in vivo synergy in BTC models, showing enhanced efficacy, reduced toxicity, and better survival with a combination comprising gemcitabine/cisplatin and CDK4/6 inhibitors. Furthermore, we demonstrated that abemaciclib monotherapy had only modest efficacy attributable to autophagy-induced resistance. Notably, triplet therapy was able to potentiate efficacy through elimination of the autophagic flux. Correspondingly, abemaciclib potentiated ribonucleotide reductase catalytic subunit M1 reduction, resulting in sensitization to gemcitabine. CONCLUSIONS: As such, these data provide robust preclinical mechanistic evidence of synergy between gemcitabine/cisplatin and CDK4/6 inhibitors and delineate a path forward for translation of these findings to preliminary clinical studies in advanced BTC patients.

Cytoreduction with Hyperthermic Intraperitoneal Chemoperfusion for Pancreatic Cancer with Low-Volume Peritoneal Metastasis: Results from a Prospective Pilot Study.

INTRODUCTION: Resection of oligometastatic pancreatic ductal adenocarcinoma (PDAC) has historically been ineffective, however modern systemic chemotherapy has improved survival. Thus, re-evaluating safety and outcomes of surgical resection in selected patients with limited peritoneal metastasis (PM) warrants consideration. METHODS: From 2018 to 2021, patients with PDAC and positive cytology or limited PM without extraperitoneal metastasis and who had an objective response to ≥ 6 months of systemic chemotherapy were enrolled. Patients underwent laparoscopic hyperthermic intraperitoneal chemotherapy (HIPEC) with cisplatin/mitomycin C. If amenable to a complete cytoreduction, patients went on to cytoreduction and HIPEC. RESULTS: Overall, 18 patients were enrolled and received a median of 14 (interquartile range [IQR] 12-17) cycles of chemotherapy; 16 (89%) patients received chemoradiation. Laparoscopic HIPEC was completed in 17 patients, with a median length of stay of 1 day, and no grade III complications or hematological toxicities were observed. All 18 patients subsequently underwent a complete cytoreduction (CC-0) along with definitive treatment of the primary tumor, with formal resection (7/18), irreversible electroporation (IRE; 10/18), or intraoperative radiation therapy (IORT; 1/18). Median PCI was 2 (IQR 0-4), median LOS was 7 days (IQR 6-8), and 7 (39%) patients were readmitted. Eight (44%) patients experienced grade 3 or higher complications, including one 30-day mortality. At a median follow-up of 16 months, the median progression-free survival was 20 months and the median overall survival was 26 months. CONCLUSION: Cytoreduction and HIPEC for selected patients with low-volume PM from PDAC is safe and feasible with favorable short-term outcomes. A phase II trial (NCT04858009) is now enrolling to further assess this multimodality approach in select patients.

Rechallenge With Switching Immune Checkpoint Inhibitors Following Autoimmune Myocarditis in a Patient With Lynch Syndrome.

Immune checkpoint inhibitors (ICIs) induce profound benefits in cancer patients with mismatch repair gene mutations or high levels of microsatellite instability. Herein, we present a case of a patient with history of Muir-Torre/Lynch syndrome and metastatic gastric adenocarcinoma in the presence of an MSH2 gene mutation. The patient was initially treated with a PD-1 inhibitor, pembrolizumab, but developed grade 4 myocarditis requiring treatment with infliximab and a prolonged steroid taper. Following discontinuation of pembrolizumab, surveillance testing showed no radiographic or endoscopic evidence of progression for 7 months, until biopsy results from a repeat upper endoscopy indicated local disease recurrence. The patient was subsequently rechallenged with another PD-1 inhibitor, nivolumab, at a 50% dose reduction without recurrent adverse events and eventually achieved a complete response after 13 cycles. This case highlights the relative importance of considering careful rechallenge with ICI therapy in patients with microsatellite instability-high malignancies and a high risk of severe adverse events.

Real-World Treatment Patterns in Patients With HER2-Amplified Metastatic Colorectal Cancer: A Clinical-Genomic Database Study.

BACKGROUND: HER2 amplification (HER2+) occurs in approximately 3% of patients with metastatic colorectal cancer (mCRC). Despite the recent addition of HER2-directed therapies to treatment recommendations in the NCCN Guidelines, until more recently there were no FDA-approved treatments. This study examined real-world treatment patterns in patients with HER2+ mCRC in the United States before and after the emerging awareness of HER2-directed therapies in 2018. METHODS: This was a retrospective observational study of patients with HER2+ mCRC from the GuardantINFORM database, which contains claims data for patients with Guardant360 genomic testing results. Patients were aged ≥18 years, were diagnosed with mCRC between January 2014 and September 2020, and had confirmed ERBB2 amplification via the blood-based Guardant360 test. Treatment patterns and real-world time to next treatment (rwTTNT) were evaluated. RESULTS: This study included 142 patients with a median age of 59 years; 31 (21.8%) patients with ERBB2 amplifications also had ERBB2 mutations. Treatment patterns were heterogeneous and evolved over time; before 2018, the most common regimen prescribed after detection of ERBB2 amplification was anti-VEGF therapy with or without chemotherapy (31.6%; n=25), and after 2018, HER2-directed therapies were the most commonly prescribed (36.5%; n=23). Median rwTTNT among the overall cohort was 8.4 months (95% CI, 6.5-10.0); rwTTNT was numerically longer in patients who received HER2-directed therapy compared with those who received non-HER2-directed therapies (11.0 months [95% CI, 6.3-12.3] vs 7.2 months [95% CI, 5.8-9.6]). CONCLUSIONS: This real-world study of the largest clinically annotated dataset of patients with HER2+ mCRC showed that many patients do not receive HER2-directed therapy despite its inclusion in NCCN Guidelines, with heterogeneous treatment patterns suggesting that standard of care remains undefined and targeted therapy remains underutilized. Greater awareness of the unmet need in this patient population, together with new effective therapies, will facilitate strategies for improved, targeted treatment approaches.

Changes in Prescribing Patterns in Stage III Colon Cancer.

BACKGROUND: For patients with resected stage III colon cancer, 6 months of adjuvant fluoropyrimidine-based chemotherapy has been the standard of care. The IDEA collaboration aimed to evaluate whether 3 months of adjuvant chemotherapy was noninferior to 6 months. Despite failing to meet its primary endpoint, the subgroup analyses demonstrated noninferiority based on regimen and treatment duration when a risk-stratified approach was used. PATIENTS AND METHODS: To evaluate the impact of the results of the IDEA collaboration, we evaluated adjuvant chemotherapy prescribing practice patterns, including planned adjuvant treatment regimen and duration from January 1, 2016, to January 31, 2021. The time period was selected to evaluate chemotherapy prescribing patterns prior to the abstract presentation of the IDEA collaboration in June 2017 and after full manuscript publication in March 2018. RESULTS: A total of 399 patients with stage III colon cancer who received adjuvant chemotherapy were included in the analysis. A significant increasing trend for use of 3 months of adjuvant chemotherapy was observed after presentation of the IDEA abstract (P<.001). A significant change in CAPOX (capecitabine/oxaliplatin) prescribing was also observed, increasing from 14% of patients prior to presentation of the IDEA abstract to 48% after presentation (P<.001). Comparing 3 months of CAPOX with 6 months of FOLFOX (fluorouracil/leucovorin/oxaliplatin), 3 months of CAPOX use also steadily increased over time (adjusted odds ratio [aOR], 1.28; 95% CI, 1.20-1.37; P<.001). Among subgroups of interest, no differences in adoption of CAPOX were observed. The adoption of 3 months of CAPOX was similar in patients with low-risk cancer (aOR, 1.27; 95% CI, 1.17-1.37) and those with high-risk cancer (aOR, 1.31; 95% CI, 1.16-1.47). CONCLUSIONS: Despite the IDEA collaboration failing to demonstrate noninferiority of 3 months' duration of adjuvant therapy compared with 6 months, the findings have influenced practice prescribing patterns, favoring CAPOX and a shorter duration of planned adjuvant treatment.

The role of microbiome in pancreatic cancer.

Recent studies of the human microbiome have offered new insights into how the microbiome can impact cancer development and treatment. Specifically, in pancreatic ductal adenocarcinoma (PDAC), the microbiota has been shown to modulate PDAC risk, contribute to tumorigenesis, impact the tumor microenvironment, and alter treatment response. These findings provide rationale for further investigations into leveraging the microbiome to develop new strategies to diagnose and treat PDAC patients. There is growing evidence that microbiome analyses have the potential to become easily performed, non-invasive diagnostic, prognostic, and predictive biomarkers in pancreatic cancer. More excitingly, there is now emerging interest in developing interventions based on the modulation of microbiota. Fecal microbiota transplantation, probiotics, dietary changes, and antibiotics are all potential strategies to augment the efficacy of current therapeutics and reduce toxicities. While there are still challenges to overcome, this is a rapidly growing field that holds promise for translation into clinical practice and provides a new approach to improving patient outcomes.

Temporal Changes in Cholangiocarcinoma Incidence and Mortality in the United States from 2001 to 2017.

BACKGROUND: Previous studies report increasing cholangiocarcinoma (CCA) incidence up to 2015. This contemporary retrospective analysis of CCA incidence and mortality in the US from 2001-2017 assessed whether CCA incidence continued to increase beyond 2015. PATIENTS AND METHODS: Patients (≥18 years) with CCA were identified in the National Cancer Institute Surveillance, Epidemiology, and End Results 18 cancer registry (International Classification of Disease for Oncology [ICD-O]-3 codes: intrahepatic [iCCA], C221; extrahepatic [eCCA], C240, C241, C249). Cancer of unknown primary (CUP) cases were identified (ICD-O-3: C809; 8140/2, 8140/3, 8141/3, 8143/3, 8147/3) because of potential misclassification as iCCA. RESULTS: Forty-thousand-and-thirty CCA cases (iCCA, n=13,174; eCCA, n=26,821; iCCA and eCCA, n=35) and 32,980 CUP cases were analyzed. From 2001-2017, CCA, iCCA, and eCCA incidence (per 100 000 person-years) increased 43.8% (3.08 to 4.43), 148.8% (0.80 to 1.99), and 7.5% (2.28 to 2.45), respectively. In contrast, CUP incidence decreased 54.4% (4.65 to 2.12). CCA incidence increased with age, with greatest increase among younger patients (18-44 years, 81.0%). Median overall survival from diagnosis was 8, 6, 9, and 2 months for CCA, iCCA, eCCA, and CUP. From 2001-2016, annual mortality rate declined for iCCA (57.1% to 41.2%) and generally remained stable for eCCA (40.9% to 37.0%) and for CUP (64.3% to 68.6%). CONCLUSIONS: CCA incidence continued to increase from 2001-2017, with greater increase in iCCA versus eCCA, whereas CUP incidence decreased. The divergent CUP versus iCCA incidence trends, with overall greater absolute change in iCCA incidence, provide evidence for a true increase in iCCA incidence that may not be wholly attributable to CUP reclassification.

Circulating tumor DNA (ctDNA) to evaluate minimal residual disease (MRD), treatment response, and posttreatment prognosis in pancreatic adenocarcinoma.

BACKGROUND: Circulating tumor DNA (ctDNA) has emerged as a blood-based test with multiple utilities in oncology. In the past few years, multiple studies of varying designs, methods, and quality have emerged which show promise for ctDNA as a tool to assess response to treatment and detect minimal residual disease (MRD) across various gastrointestinal (GI) malignancies. We aim to review the current literature for ctDNA as it pertains to assessing treatment response, MRD, prognosis, and risk of recurrence for pancreatic adenocarcinoma. METHODS: PubMed was queried with a combination of terms regarding pancreatic adenocarcinoma, minimal residual disease, resection, and prognosis. All resultant articles were reviewed by the authors for appropriate fit with scope. RESULTS: Fourteen articles were identified that fit with the scope of this review. CONCLUSIONS: Detectable ctDNA after definitive resection, specifically mutated KRAS, correlates with shorter recurrence-free survival (RFS), overall survival (OS), and overall prognosis. Limited data also suggests ctDNA may provide a noninvasive means to assess response to chemotherapy. Whether this information is actionable in terms of altering neoadjuvant or postresection treatment regimens remains an open question requiring further study.

Circulating Tumor DNA-Based Testing and Actionable Findings in Patients with Advanced and Metastatic Pancreatic Adenocarcinoma.

PURPOSE: Recent advances in molecular diagnostic technologies allow for the evaluation of solid tumor malignancies through noninvasive blood sampling, including circulating tumor DNA profiling (ctDNA). Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis, often because of late presentation of disease. Diagnosis is often made using endoscopic ultrasound or endoscopic retrograde cholangiopancreatography, which often does not yield enough tissue for next-generation sequencing. With this study, we sought to characterize the ctDNA genomic alteration landscape in patients with advanced PDAC with a focus on actionable findings. MATERIALS AND METHODS: From December 2014 through October 2019, 357 samples collected from 282 patients with PDAC at Mayo Clinic underwent ctDNA testing using a clinically available assay. The majority of samples were tested using the 73-gene panel which includes somatic genomic targets, including complete or critical exon coverage in 30 and 40 genes, respectively, and in some, amplifications, fusions, and indels. Clinical data and outcome variables were available for 165 patients; with 104 patients at initial presentation. RESULTS: All patients included in this study had locally advanced or metastatic PDAC. Samples having at least one alteration, when variants of unknown significance (VUS) were excluded, numbered 266 (75%). After excluding VUS, therapeutically relevant alterations were observed in 170 (48%) of the total 357 cohort, including KRAS (G12C), EGFR, ATM, MYC, BRCA, PIK3CA, and BRAF mutations. KRAS, SMAD, CCND2, or TP53 alterations were seen in higher frequency in patients with advanced disease. CONCLUSION: Our study is the largest cohort to date that demonstrates the feasibility of ctDNA testing in PDAC. We provide a benchmark landscape upon which the field can continue to grow. Future applications may include use of ctDNA to guide treatment and serial monitoring of ctDNA during disease course to identify novel therapeutic targets for improved prognosis. IMPLICATIONS FOR PRACTICE: Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis often due to late presentation of disease. Biopsy tissue sampling is invasive and samples are often inadequate, requiring repeated invasive procedures and delays in treatment. Noninvasive methods to identify PDAC early in its course may improve prognosis in PDAC. Using ctDNA, targetable genes can be identified and used for treatment.

Nanoliposomal irinotecan (Nal-IRI)-based chemotherapy after irinotecan -based chemotherapy in patients with pancreas cancer.

BACKGROUND: Nanoliposomal irinotecan (Nal-IRI) is a preferred second-line treatment for metastatic pancreas cancer. It is unclear, however, whether patients who had received irinotecan derive benefit. METHODS: Medical records of metastatic pancreas cancer patients who had received irinotecan and then Nal-IRI were reviewed. The primary endpoint was overall survival after the initiation of Nal-IRI (an a priori threshold of >4 months defined success); adverse events and quotes from the medical record on decision-making were also recorded. RESULTS: Sixty four patients met eligibility criteria with a median age of 65 years (range: 36, 80 years). The median overall survival from initiation of Nal-IRI was 5.1 months (95% confidence interval (CI): 4.3, 5.6 months). An exploratory comparison, based on no cancer progression with irinotecan versus progression, showed improved survival with Nal-IRI in the former group: 6.1 months (95% CI: 5.1, 9.3 months) versus 4.3 months (95% CI: 2.3, 4.8 months); p = 0.0006. Nal-IRI adverse events occurred as expected. Qualitative data illustrate several themes, including "limited treatment options," which appeared to drive the decision to prescribe Nal-IRI. CONCLUSION: Nal-IRI might be considered in pancreas cancer patients who had received irinotecan, particularly in the absence of disease progression with the latter.

Transitioning from second-line to third-line therapy in metastatic colorectal cancer.

In the setting of metastatic colorectal cancer, many gains in patient outcomes have been achieved throughout the last 2 decades. A primary driver of these gains is access to more lines of therapy. In the palliative metastatic setting, all patients ultimately progress and require continued treatment sequencing. The goal is to expose patients to all lines of available therapies. It is now possible to better select patients for each therapy. Treatment selection algorithms encompass disease factors and patient characteristics, such as overall condition and age. Appropriate molecular profiling assessments should be available early in the treatment course, to drive decision-making and allow use of alternative therapies when possible. The transition to third-line therapy can be prompted by changes in imaging scans or laboratory tests, as well as changes in the patient's symptom burden. It can be problematic to delay initiation of third-line therapy when it is clinically indicated. Many oncologists will consider rechallenging patients with the same chemotherapy that did not work earlier. Although this strategy is reasonable, it should not necessarily take precedence over use of agents with proven efficacy in later lines of therapy in randomized clinical trials, such as regorafenib and trifluridine/tipiracil. Clinicians now commonly adjust the dose of regorafenib. A delay in the initiation of these third-line agents can allow the patient's performance status to decrease, thus diminishing the opportunity for a successful outcome.

How quality of life can inform management decisions in later-line metastatic colorectal cancer.

For many years, the focus of treatment in patients with metastatic colorectal cancer has been to prolong patient survival. Increasing evidence, however, highlights the quality-of-life issues these patients face as they progress through lines of treatment. Quality of life is important to patients with metastatic colorectal cancer, and can greatly impact their overall well-being. Some studies have found associations between quality of life and survival. The approval by the US Food and Drug Administration of regorafenib and trifluridine/tipiracil in the third-line setting for patients with metastatic disease provided an option for salvage therapy that improved overall survival in heavily pretreated patients. The safety profile of each agent can help guide selection. Patients with metastatic colorectal cancer require an individualized treatment strategy that incorporates their age, comorbidities, and prior treatments. New data on quality-of-life measures from pivotal clinical trials also provide insight into selection of treatment. These factors should be considered along with the patient's preferences and individual treatment goals.

Role of Surgery and Perioperative Therapy in Older Patients with Resectable Pancreatic Ductal Adenocarcinoma.

BACKGROUND: It is unclear whether results from recent trials of resectable pancreatic ductal adenocarcinoma (PDAC) are generalizable to older patients, who are underrepresented. We aimed to evaluate outcomes of surgery and of neoadjuvant and adjuvant therapy in older patients with resectable PDAC. PATIENTS AND METHODS: We included patients aged ≥65 years with upfront resectable PDAC from a prospectively maintained pancreatic cancer registry from 2007 to 2016. Patients were stratified into ages 65-75 and 75+ years. Overall survival (OS) was assessed in treatment comparisons: (A) surgery (n = 636) versus nonsurgical (n = 178), (B) neoadjuvant therapy (n = 139) versus upfront surgery (n = 497), and (C) adjuvant therapy (n = 379) versus surgery alone (n = 118). We compared neoadjuvant (n = 139) versus adjuvant therapy (n = 379) in an exploratory analysis. RESULTS: Nine hundred and three patients had a median age of 73.7 (range, 65-96.6) years. Median OS was 26.6 versus 11.9 months (adjusted hazard ratio [HRadj ], 0.4; 95% confidence interval [CI], 0.31-0.52; p < .001) in Comparison A groups, 30.7 versus 25.8 months (HRadj , 0.69; 95% CI, 0.49-0.96; p = .03) in Comparison B groups, and 26.9 versus 17.4 months (HRadj , 0.62; 95% CI, 0.44-0.88; p = .008) in Comparison C groups, respectively. OS benefit in these treatment comparisons was present in age group 75+ with HRadj 0.24 (95% CI, 0.16-0.36; p < .001) in Comparison A and HRadj 0.52 (95% CI, 0.27-1; p = .049) in Comparison B, but not in Comparison C with HRadj 0.68 (95% CI, 0.43-1.08; p = .1). Statistically comparable median OS of patients who received neoadjuvant or adjuvant therapy stratified by age groups was observed. CONCLUSION: Older patients with resectable PDAC who received surgery, neoadjuvant therapy, or adjuvant therapy appeared to have improved survival outcomes compared with those who did not receive such treatment. IMPLICATIONS FOR PRACTICE: Older patients with resectable pancreatic ductal adenocarcinoma (PDAC) in general are underrepresented in large clinical trials and less well studied in terms of the role of surgery, neoadjuvant therapy, and adjuvant therapy. This study collected data on older patients with resectable PDAC from a prospectively maintained single-institutional pancreatic cancer registry of a tertiary referral center from 2007 to 2016. It was found that, with multidisciplinary evaluation, older patients with resectable PDAC who received surgery, neoadjuvant therapy, or adjuvant therapy appeared to have improved survival outcomes compared with those who did not receive such treatment. These results are of substantial importance to practitioners who treat older patients, who are traditionally underrepresented in most clinical trials.

Phase II Trial of Trifluridine/Tipiracil in Patients with Advanced, Refractory Biliary Tract Carcinoma.

LESSONS LEARNED: Trifluridine/tipiracil (FTD/TPI) shows promising antitumor activity in heavily pretreated patients with advanced biliary tract carcinoma, including patients with 5-fluorouracil refractory tumors. FTD/TPI has an acceptable safety profile and should be studied further in patients with advanced biliary tract carcinoma after progression on standard first-line therapy. BACKGROUND: Patients with advanced biliary tract carcinoma (BTC) refractory to first-line therapy lack an established second-line option. Trifluridine/tipiracil (FTD/TPI) has activity in both fluoropyrimidine-sensitive and -resistant tumors, which led us to conduct a single arm phase II trial to evaluate the safety and efficacy of FTD/TPI for patients previously treated for advanced BTC. METHODS: Patients with advanced BTC previously treated with at least one line of chemotherapy were enrolled and treated with FTD/TPI until disease progression or unacceptable toxicity. The primary endpoint target was to have at least 6 patients who were progression free and alive at 16 weeks among 25 evaluable patients. Secondary endpoints included overall survival (OS), overall response rate (ORR), progression-free survival (PFS), and toxicity. RESULTS: Of 27 evaluable patients, 59.3% received at least three prior lines of therapy, and 81.5% had previous exposure to fluoropyrimidine. Eight (32%, 95% confidence interval [CI], 14.9%-53.5%) patients were progression free at 16 weeks in the primary analysis population (n = 25), which met the predefined efficacy criteria. Median PFS and OS were 3.8 (95% CI, 2-5.8 months) and 6.1 (95% CI, 4.4-11.4 months) months, respectively. No objective responses were seen. There were no unexpected safety signals noted. CONCLUSION: FTD/TPI demonstrated promising antitumor activity, with acceptable toxicity, in heavily pretreated patients with advanced BTC.