Efficacy and Safety of Adagrasib plus Cetuximab in Patients with KRASG12C-Mutated Metastatic Colorectal Cancer.

Adagrasib, an irreversible, selective KRASG12C inhibitor, may be an effective treatment in KRASG12C-mutated colorectal cancer, particularly when combined with an anti-EGFR antibody. In this analysis of the KRYSTAL-1 trial, patients with previously treated KRASG12C-mutated unresectable or metastatic colorectal cancer received adagrasib (600 mg twice daily) plus cetuximab. The primary endpoint was objective response rate (ORR) by blinded independent central review. Ninety-four patients received adagrasib plus cetuximab. With a median follow-up of 11.9 months, ORR was 34.0%, disease control rate was 85.1%, and median duration of response was 5.8 months (95% confidence interval [CI], 4.2-7.6). Median progression-free survival was 6.9 months (95% CI, 5.7-7.4) and median overall survival was 15.9 months (95% CI, 11.8-18.8). Treatment-related adverse events (TRAEs) occurred in all patients; grade 3-4 in 27.7% and no grade 5. No TRAEs led to adagrasib discontinuation. Exploratory analyses suggest circulating tumor DNA may identify features of response and acquired resistance. SIGNIFICANCE: Adagrasib plus cetuximab demonstrates promising clinical activity and tolerable safety in heavily pretreated patients with unresectable or metastatic KRASG12C-mutated colorectal cancer. These data support a potential new standard of care and highlight the significance of testing and identification of KRASG12C mutations in patients with colorectal cancer.

Treatment options for HER2-expressing colorectal cancer: updates and recent approvals.

Colorectal cancer is a leading cause of cancer-related mortality worldwide. Approximately 3-5% of colorectal tumors harbor human epidermal growth factor receptor (HER2) amplification which is associated with a higher incidence of intracranial metastasis and overall worse outcomes. In the setting of refractory metastatic RAS wild-type tumors, evidence supports the use of various HER2-blocking agents, including monoclonal antibodies, tyrosine kinase inhibitors, and novel antibody-drug conjugates. With a number of relatively active agents clinically available and even more in development, it is crucial for clinicians to familiarize themselves with the mechanisms of action, efficacy data, and safety profiles of these treatments. In this review, we aim to summarize key findings from past and ongoing trials with anti-HER2 agents in metastatic colorectal cancer.

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).

PD-1 Blockade Induces Reactivation of Nonproductive T-Cell Responses Characterized by NF-κB Signaling in Patients with Pancreatic Cancer.

PURPOSE: Pancreatic ductal adenocarcinoma (PDAC) trials have evaluated CTLA-4 and/or PD-(L)1 blockade in patients with advanced disease in which bulky tumor burden and limited time to develop antitumor T cells may have contributed to poor clinical efficacy. Here, we evaluated peripheral blood and tumor T cells from patients with PDAC receiving neoadjuvant chemoradiation plus anti-PD-1 (pembrolizumab) versus chemoradiation alone. We analyzed whether PD-1 blockade successfully reactivated T cells in the blood and/or tumor to determine whether lack of clinical benefit could be explained by lack of reactivated T cells versus other factors. EXPERIMENTAL DESIGN: We used single-cell transcriptional profiling and TCR clonotype tracking to identify TCR clonotypes from blood that match clonotypes in the tumor. RESULTS: PD-1 blockade increases the flux of TCR clonotypes entering cell cycle and induces an IFNγ signature like that seen in patients with other GI malignancies who respond to PD-1 blockade. However, these reactivated T cells have a robust signature of NF-κB signaling not seen in cases of PD-1 antibody response. Among paired samples between blood and tumor, several of the newly cycling clonotypes matched activated T-cell clonotypes observed in the tumor. CONCLUSIONS: Cytotoxic T cells in the blood of patients with PDAC remain sensitive to reinvigoration by PD-1 blockade, and some have tumor-recognizing potential. Although these T cells proliferate and have a signature of IFN exposure, they also upregulate NF-κB signaling, which potentially counteracts the beneficial effects of anti-PD-1 reinvigoration and marks these T cells as non-productive contributors to antitumor immunity. See related commentary by Lander and DeNardo, p. 474.

Multicenter randomized controlled trial of neoadjuvant chemoradiotherapy alone or in combination with pembrolizumab in patients with resectable or borderline resectable pancreatic adenocarcinoma.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a challenging target for immunotherapy because it has an immunosuppressive tumor microenvironment. Neoadjuvant chemoradiotherapy can increase tumor-infiltrating lymphocyte (TIL) density, which may predict overall survival (OS). We hypothesized that adding programmed cell death protein 1 (PD-1) blockade to chemoradiotherapy would be well tolerated and increase TILs among patients with localized PDAC. METHODS: Patients were randomized 2:1 to Arm A (receiving pembrolizumab plus chemoradiotherapy (capecitabine and external beam radiation)) or Arm B (receiving chemoradiotherapy alone) before anticipated pancreatectomy. Primary endpoints were (1) incidence and severity of adverse events during neoadjuvant therapy and (2) density of TILs in resected tumor specimens. TIL density was assessed using multiplexed immunofluorescence histologic examination. RESULTS: Thirty-seven patients were randomized to Arms A (n=24) and B (n=13). Grade ≥3 adverse events related to neoadjuvant treatment were experienced by 9 (38%) and 4 (31%) patients in Arms A and B, respectively, with one patient experiencing dose-limiting toxicity in Arm A. Seventeen (71%) and 7 (54%) patients in Arms A and B, respectively, underwent pancreatectomy. Median CD8+ T-cell densities in Arms A and B were 67.4 (IQR: 39.2-141.8) and 37.9 (IQR: 22.9-173.4) cells/mm2, respectively. Arms showed no noticeable differences in density of CD8+Ki67+, CD4+, or CD4+FOXP3+ regulatory T cells; M1-like and M2-like macrophages; or granulocytes. Median OS durations were 27.8 (95% CI: 17.1 to NR) and 24.3 (95% CI: 12.6 to NR) months for Arms A and B, respectively. CONCLUSIONS: Adding pembrolizumab to neoadjuvant chemoradiotherapy was safe. However, no convincing effect on CD8+ TILs was observed.

Targeting ERBB2/HER2 genetic alterations: an expanding therapeutic opportunity in gastrointestinal cancers.

HER2 amplification and/or activating variations of its protein, human epidermal growth factor receptor 2 (HER2), are associated with distinct clinical and pathological features in gastrointestinal tumors, including a worse overall prognosis and a higher incidence of metastastic lesions in the central nervous system. Notably, the role of HER2 as a therapeutic target continues to expand beyond the scope of breast and gastroesophageal tumors, now encompassing colorectal and biliary tract cancers (BTCs), among others. In parallel, there is a burgeoning array of therapeutic agents designed to inhibit the activity of the HER2 pathway, including monoclonal antibodies, orally available tyrosine kinase inhibitors, bispecific antibodies, and antibody-drug conjugate compounds. In this comprehensive review, we will explore the current body of evidence that supports the implementation of HER2-targeting strategies in the treatment of patients with gastric, esophageal, colorectal, and biliary tract tumors. We will also describe testing methods for HER2 status in clinical practice, including immunohistochemistry (IHC), and its correlation with next-generation sequencing-based techniques. Additionally, we will review the key treatment-related adverse events associated with specific anti-HER2 agents, emphasizing the need for early diagnosis and effective management. Furthermore, a critical aspect of this exploration is determining the optimal treatment sequencing among the available therapies, which will be pivotal in enhancing treatment outcomes.

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.

Efficacy of Immune Checkpoint Inhibition and Cytotoxic Chemotherapy in Mismatch Repair-Deficient and Microsatellite Instability-High Pancreatic Cancer: Mayo Clinic Experience.

PURPOSE: Pancreatic cancer (PC) carries a poor prognosis with high rates of unresectable/metastatic disease at diagnosis, recurrence after resection, and few systemic therapy options. Deficient mismatch repair (dMMR)/high microsatellite instability (MSI-H) PCs demonstrated uncharacteristically poor outcomes in KEYNOTE-158, evaluating pembrolizumab in MSI-H solid tumors. Our study aggregates the Mayo Clinic experience with dMMR/MSI-H PCs, characterizing the clinical, molecular, and treatment response patterns with a focus on response to immune checkpoint inhibitors (ICIs). METHODS: Retrospective data were collected from the electronic medical record from December 2009 to February 2023. Patients were included if they had a pathologically confirmed pancreatic malignancy and had (1) deficient expression of mismatch repair (MMR) proteins by tumor immunohistochemistry, (2) pathogenic mutation of MMR genes on genomic sequencing, and/or (3) MSI-H by polymerase chain reaction. RESULTS: Thirty-two patients were identified for inclusion, with all stages of disease represented. Sixteen of these patients underwent surgery or chemoradiotherapy. Of these patients, uncharacteristically favorable responses were seen, with a recurrence rate of only 19% (n = 3) despite a median follow-up of 25 months. In the palliative setting, excellent responses to ICI were seen, with overall response rate (ORR) of 75% (20% complete response). Median time to disease progression was not reached. Response rates to cytotoxic chemotherapy in the palliative setting were poor, with 30% ORR and median time to progression of 4 months. We observed a high rate of discrepancy between MMR and MSI testing methods, representing 19% of the entire cohort and 26% of evaluable cases. CONCLUSION: Our data argue for the preferential use of ICI over cytotoxic chemotherapy in any patient with dMMR/MSI-H PC requiring systemic therapy, including in the metastatic and adjuvant/neoadjuvant settings.

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.

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.

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.

Universal Genetic Testing vs. Guideline-Directed Testing for Hereditary Cancer Syndromes Among Traditionally Underrepresented Patients in a Community Oncology Program.

Background Detection of pathogenic germline variants (PGVs) has implications for cancer screening, prognosis, treatment selection, clinical trial enrollment, and family testing. Published guidelines provide indications for PGV testing, determined by clinical and demographic factors, but their applicability in an ethnically and racially diverse community hospital population is unknown. This study describes the diagnostic and incremental yield of universal multi-gene panel testing in a diverse population in a community cancer practice. Methods We completed a prospective study of proactive germline genetic sequencing among patients with solid tumor malignancies at a community-based oncology practice in downtown Jacksonville, FL, between June 2020 and September 2021. The patients were unselected for cancer type, stage, family history, race/ethnicity, and age. PGVs identified using an 84-gene next-generation sequencing (NGS) tumor genomic testing platform were stratified by penetrance. National Comprehensive Cancer Networks (NCCN) guidelines determined incremental PGV rates. Results Two hundred twenty-three patients were enrolled, with a median age of 63 years, 78.5% female. 32.7% were Black/African American, and 5.4% were Hispanic. 39.9% of patients were commercially insured, Medicare/Medicaid insured 52.5%, and 2.7% were uninsured. The most common cancers in this cohort were breast (61.9%), lung (10.3%), and colorectal (7.2%). Twenty-three patients (10.3%) carried one or more PGVs, and 50.2% carried a variant of uncertain significance (VUS). Though there was no significant difference in the rate of PGVs based on race/ethnicity, African Americans were numerically more likely to have a VUS reported than whites (P=0.059). Eighteen (8.1%) patients had incremental clinically actionable findings that practice guidelines would not have detected, which was higher in non-whites. Conclusions In this racially/ethnically and socioeconomically diverse cohort, universal multi-gene panel testing (MGPT) increased diagnostic yield over targeted guideline-informed testing. Rates of VUS and incremental PGV were higher in non-white populations.

Adagrasib in Advanced Solid Tumors Harboring a KRASG12C Mutation.

PURPOSE: Adagrasib, a KRASG12C inhibitor, has demonstrated clinical activity in patients with KRASG12C-mutated non-small-cell lung cancer (NSCLC) and colorectal cancer (CRC). KRASG12C mutations occur rarely in other solid tumor types. We report evaluation of the clinical activity and safety of adagrasib in patients with other solid tumors harboring a KRASG12C mutation. METHODS: In this phase II cohort of the KRYSTAL-1 study (ClinicalTrials.gov identifier: NCT03785249; phase Ib cohort), we evaluated adagrasib (600 mg orally twice daily) in patients with KRASG12C-mutated advanced solid tumors (excluding NSCLC and CRC). The primary end point was objective response rate. Secondary end points included duration of response, progression-free survival (PFS), overall survival, and safety. RESULTS: As of October 1, 2022, 64 patients with KRASG12C-mutated solid tumors were enrolled and 63 patients treated (median follow-up, 16.8 months). The median number of prior lines of systemic therapy was 2. Among 57 patients with measurable disease at baseline, objective responses were observed in 20 (35.1%) patients (all partial responses), including 7/21 (33.3%) responses in pancreatic and 5/12 (41.7%) in biliary tract cancers. The median duration of response was 5.3 months (95% CI, 2.8 to 7.3) and median PFS was 7.4 months (95% CI, 5.3 to 8.6). Treatment-related adverse events (TRAEs) of any grade were observed in 96.8% of patients and grade 3-4 in 27.0%; there were no grade 5 TRAEs. TRAEs did not lead to treatment discontinuation in any patients. CONCLUSION: Adagrasib demonstrates encouraging clinical activity and is well tolerated in this rare cohort of pretreated patients with KRASG12C-mutated solid tumors.

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.).

Understanding Suboptimal Response to Immune Checkpoint Inhibitors.

Immune checkpoint inhibitors (ICIs), as a novel class of anticancer therapy, can be more efficacious and less toxic than chemotherapy, but their clinical success is confined to certain tumor types. Elucidating their targets, mechanisms and scope of action, and potential synergism with chemotherapy and/or targeted therapies are critical to widen their clinical indications. Treatment response to an ICI targeting programmed death-1 (anti-PD-1) is sought to be understood here by conducting a preplanned correlative analysis of a phase II clinical trial in patients with small bowel adenocarcinoma (SBA). The cytolytic capacity of circulating immune cells in cancer patients using a novel ex vivo cytotoxicity assay is evaluated, and the utility of circulating biomarkers is investigated to predict and monitor the treatment effect of anti-PD-1. Baseline expression of Bim and NKG7 and upregulation of CX3CR1 in circulating T cells are associated with the clinical benefit of anti-PD-1 in patients with SBA. Overall, these findings suggest that the frequency and cytolytic capacity of circulating, effector immune cells may differentiate clinical response to ICIs, providing a strong rationale to support immune monitoring using patient peripheral blood.

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.

Cabozantinib Following Immunotherapy in Patients with Advanced Hepatocellular Carcinoma.

(1) Background: Cabozantinib, a multikinase inhibitor, is approved by the Food and Drug Administration (FDA) for the treatment of advanced hepatocellular carcinoma (HCC) following progression on sorafenib. Recently, atezolizumab plus bevacizumab has been approved in the first line setting for advanced HCC and has become the new standard of care. Whether cabozantinib improves outcomes following progression on immunotherapy remains unknown. We describe the clinical outcomes following treatment with immunotherapy in patients with advanced HCC who received cabozantinib. (2) Methods: We conducted a multicentric, retrospective analysis of patients with advanced HCC diagnosed between 2010-2021 at Mayo Clinic in Minnesota, Arizona, and Florida who received cabozantinib. Median overall survival and progression free survival analyses were performed using the Kaplan-Meier method. Adverse events were determined using Common Terminology Criteria for Adverse Events (CTCAE). (3). Results: We identified 26 patients with advanced HCC who received cabozantinib following progression on immunotherapy. Median progression free survival on cabozantinib therapy was 2.1 months (95% CI: 1.3-3.9) and median overall survival from time of cabozantinib initiation was 7.7 months (95% CI: 5.3-14.9). (4) Conclusion: The optimal sequencing of therapy for patients with advanced HCC following progression on immunotherapy remains unknown. Our study demonstrates that patients may benefit from treatment with cabozantinib following progression on immunotherapy.