Citations

Abstract 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

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.

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.

ImportanceSystematic data on the association between anticancer therapies and thromboembolic events (TEEs) in patients with COVID-19 are lacking.ObjectiveTo assess the association between anticancer therapy exposure within 3 months prior to COVID-19 and TEEs following COVID-19 diagnosis in patients with cancer.Design, Setting, and ParticipantsThis registry-based retrospective cohort study included patients who were hospitalized and had active cancer and laboratory-confirmed SARS-CoV-2 infection. Data were accrued from March 2020 to December 2021 and analyzed from December 2021 to October 2022.ExposureTreatments of interest (TOIs) (endocrine therapy, vascular endothelial growth factor inhibitors/tyrosine kinase inhibitors [VEGFis/TKIs], immunomodulators [IMiDs], immune checkpoint inhibitors [ICIs], chemotherapy) vs reference (no systemic therapy) in 3 months prior to COVID-19.Main Outcomes and MeasuresMain outcomes were (1) venous thromboembolism (VTE) and (2) arterial thromboembolism (ATE). Secondary outcome was severity of COVID-19 (rates of intensive care unit admission, mechanical ventilation, 30-day all-cause mortality following TEEs in TOI vs reference group) at 30-day follow-up.ResultsOf 4988 hospitalized patients with cancer (median [IQR] age, 69 [59-78] years; 2608 [52%] male), 1869 had received 1 or more TOIs. Incidence of VTE was higher in all TOI groups: endocrine therapy, 7%; VEGFis/TKIs, 10%; IMiDs, 8%; ICIs, 12%; and chemotherapy, 10%, compared with patients not receiving systemic therapies (6%). In multivariable log-binomial regression analyses, relative risk of VTE (adjusted risk ratio [aRR], 1.33; 95% CI, 1.04-1.69) but not ATE (aRR, 0.81; 95% CI, 0.56-1.16) was significantly higher in those exposed to all TOIs pooled together vs those with no exposure. Among individual drugs, ICIs were significantly associated with VTE (aRR, 1.45; 95% CI, 1.01-2.07). Also noted were significant associations between VTE and active and progressing cancer (aRR, 1.43; 95% CI, 1.01-2.03), history of VTE (aRR, 3.10; 95% CI, 2.38-4.04), and high-risk site of cancer (aRR, 1.42; 95% CI, 1.14-1.75). Black patients had a higher risk of TEEs (aRR, 1.24; 95% CI, 1.03-1.50) than White patients. Patients with TEEs had high intensive care unit admission (46%) and mechanical ventilation (31%) rates. Relative risk of death in patients with TEEs was higher in those exposed to TOIs vs not (aRR, 1.12; 95% CI, 0.91-1.38) and was significantly associated with poor performance status (aRR, 1.77; 95% CI, 1.30-2.40) and active/progressing cancer (aRR, 1.55; 95% CI, 1.13-2.13).Conclusions and RelevanceIn this cohort study, relative risk of developing VTE was high among patients receiving TOIs and varied by the type of therapy, underlying risk factors, and demographics, such as race and ethnicity. These findings highlight the need for close monitoring and perhaps personalized thromboprophylaxis to prevent morbidity and mortality associated with COVID-19–related thromboembolism in patients with cancer.

Metastatic colorectal cancer (mCRC) is a heterogeneous disease that can evoke discordant responses to therapy among different lesions in individual patients. The Response Evaluation Criteria in Solid Tumors (RECIST) criteria do not take into consideration response heterogeneity. We explored and developed lesion-based measurement response criteria to evaluate their prognostic effect on overall survival (OS). Patients and Methods: Patients enrolled in 17 first-line clinical trials, who had mCRC with ≥ 2 lesions at baseline, and a restaging scan by 12 weeks were included. For each patient, lesions were categorized as a progressing lesion (PL: > 20% increase in the longest diameter (LD)), responding lesion (RL: > 30% decrease in LD), or stable lesion (SL: neither PL nor RL) based on the 12-week scan. Lesion-based response criteria were defined for each patient as follows: PL only, SL only, RL only, and varied responses (mixture of RL, SL, and PL). Lesion-based response criteria and OS were correlated using stratified multivariable Cox models. The concordance between OS and classifications was measured using the C statistic. Results: Among 10,551 patients with mCRC from 17 first-line studies, varied responses were noted in 51.6% of patients, among whom, 3.3% had RL/PL at 12 weeks. Among patients with RL/SL, 52% had stable disease (SD) by RECIST 1.1, and they had a longer OS (median OS (mOS) = 19.9 months) than those with SL only (mOS = 16.8 months, HR (95% CI) = 0.81 (0.76, 0.85), p < 0.001), although a shorter OS than those with RL only (mOS = 25.8 months, HR (95% CI) = 1.42 (1.32, 1.53), p < 0.001). Among patients with SL/PL, 74% had SD by RECIST 1.1, and they had a longer OS (mOS = 9.0 months) than those with PL only (mOS = 8.0 months, HR (95% CI) = 0.75 (0.57, 0.98), p = 0.040), yet a shorter OS than those with SL only (mOS = 16.8 months, HR (95% CI) = 1.98 (1.80, 2.18), p < 0.001). These associations were consistent across treatment regimen subgroups. The lesion-based response criteria showed slightly higher concordance than RECIST 1.1, although it was not statistically significant. Conclusion: Varied responses at first restaging are common among patients receiving first-line therapy for mCRC. Our lesion-based measurement criteria allowed for better mortality discrimination, which could potentially be informative for treatment decision-making and influence patient outcomes.

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.

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.

Abstract 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.

e22537 Background: Germline and tumor next-generation sequencing (NGS) are complementary tests whose benefit in capturing patients (pts) potentially eligible for precision therapies is maximized when the tests are paired, as qualifying pathogenic variants (PVs) are missed if either test was done in isolation (Lincoln et al. 2020). Germline NGS has the additional benefit of informing prevention through surveillance and cascade testing. We highlight the benefits of a universal approach to concurrent testing in a subset of the previously reported cohort of pan-cancer pts who underwent universal germline NGS (Samadder et al. 2020). Methods: Unselected pts with solid tumors underwent an 80+ gene germline panel and 315+ gene tumor panel. Variants in genes unique to the germline or tumor panels, including microsatellite instability (MSI) and tumor mutation burden (TMB), were also evaluated. Results: 104 pts [81.7% White, non-Hispanic, 71.2% male] with 23 cancer types [28% colorectal, 13% lung, 11% prostate, 49% other] were included. Five (5%) pts had no actionable tumor alterations or germline variants identified (Table). 18 pts (17%) had 19 pathogenic germline variants (PGVs) identified, 11 (58%) of which were detected on tumor NGS (Table). 92 pts had >1 tumor alteration identified, of which 12% were confirmed as PGVs (Table). Notably, tumor NGS revealed 81 pts (78%) pts with biomarkers that would could not have been identified with germline testing alone, such as variants in genes not on germline panel (80) or MSI-high (4), or TMB-high (21) status of the tumor. Conclusions: Germline and tumor NGS are complementary tests that often detect different actionable alterations. There is value in confirming both the presence and absence of somatic variants in the germline in order to make appropriate clinical recommendations for the patient and their family members. [Table: see text]

TPS4178 Background: Despite advances in treatment for unresectable hepatocellular carcinoma (HCC), long-term survival rates remain poor. The combination of bevacizumab (Bev) and atezolizumab (Atezo) is the preferred frontline therapy for advanced HCC, but a minority of patients (pts) respond, and secondary resistance usually occurs within months. HCC has an immune-suppressed tumor microenvironment, mediated by activated immune checkpoint signaling and angiogenesis pathways, which may contribute to therapeutic resistance. RP3 is a genetically modified herpes simplex virus type 1 (HSV-1) that expresses the fusogenic gibbon ape leukemia virus glycoprotein with the R sequence deleted (GALV-GP-R–), an anti–CTLA-4 antibody-like molecule, CD40 ligand, and 4-1BB ligand. The direct oncolytic effect coupled with immune stimulation by RP3 in the tumor microenvironment is intended to provide systemic antitumor activity and enhance therapeutic response to anti–PD-1/PD-L1 agents, such as Atezo. Preclinical data have demonstrated improved distribution of oncolytic HSV within tumors in combination with Bev, supporting the clinical combination of RP3 with Bev. This study will evaluate the safety and efficacy of RP3 combined with Atezo and Bev as first- (1L) and second-line (2L) systemic therapies for unresectable and advanced HCC. Methods: The 1L and 2L cohorts will each enroll up to 30 pts. Pts in the 1L cohort may not have received prior systemic treatment; pts in the 2L cohort must have progressed on or following one prior line of systemic therapy, which must have included a PD-1/PD-L1−directed agent. Key inclusion criteria include advanced, unresectable HCC with ≥1 measurable tumor of ≥1 cm in longest diameter, Child-Pugh Class A, and Eastern Cooperative Oncology Group performance status of 0−1. Key exclusion criteria include untreated esophageal and/or gastric varices with bleeding or at high risk for bleeding and macroscopic invasion of tumor into any major blood vessel(s) and/or main bile ducts. Pts with a history of medically refractory hepatic encephalopathy and/or hepato-renal syndrome are also excluded. Pts in the 1L cohort will receive 1200 mg Atezo and 15 mg/kg Bev every 3 weeks (Q3W) together with RP3 intratumorally Q3W for a total of up to 8 doses. Pts in the 2L cohort will receive RP3 every 2 weeks for 4 doses with Bev Q3W starting on cycle (C) 1 day (D) 1, then RP3 and Bev Q3W for up to 4 more doses with Atezo Q3W being added on C4D1. The primary endpoint is overall response rate (ORR) by Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. Secondary endpoints are safety, ORR using HCC modified RECIST, duration of response, complete response rate, and progression-free survival. Clinical trial information: NCT05733598 .