Mismatch Repair Proficient Tumors Research Articles

Nivolumab plus ONC201 plus in microsatellite stable (MSS) metastatic colorectal cancer (mCRC) patients: a Brown University Oncology Research Group phase Ib/II study (BrUOG379).

Immune checkpoint inhibitors alone, or in combination with chemotherapy failed to provide meaningful clinical activity for patients with microsatellite stable (MSS) colorectal cancer (CRC). ONC201 is a small molecule that inactivates AKT and ERK signaling and actives the TRAIL pathway. Preclinical studies indicated potential benefits of combining ONC201 with checkpoint inhibitors. This is a phase Ib/II trial of ONC201 plus nivolumab for patient with MSS CRC who progressed on standard treatment. Enrolled patients received ONC201 plus nivolumab in a dose de-escalation fashion to determine the maximum tolerated dose (MTD). Additional patients were enrolled in the dose-expansion cohort. ONC201 at a dose of 625 mg was given orally at day -7 of cycle 1, followed by weekly dosing. Nivolumab was given every 2 weeks at 240 mg IV starting on day 1 of every cycle (cycle =28 days). The primary end point was dose-limiting toxicity (DLT) during the observation window (run-in dose day -7, cycle 1 to assessment pre-dosing cycle 2). The plan was to enroll 28 additional patients at the MTD so that a total of 34 patients would be treated at the MTD. Pharmacokinetics (PKs) and tumor biopsies were collected at several time points per study protocol. A total of 13 patients (8 patients in the dose escalation *6 evaluable*) were enrolled between December 4, 2019 and March 2021. All patients had received ≥2 previous lines of chemotherapy and had confirmed microsatellite stability or mismatch repair-proficient tumors. No DLTs were observed with 625 mg ONC201 in the first three patients. Three additional patients were enrolled at the same dose to confirm safety. Two patients progressed during the DLT period and had to be replaced. During the dose-expansion part, five patients were enrolled and none required dose reduction or modification. No objective tumor response was observed in the 13 treated patients. Disease progression was confirmed at the time of the first imaging evaluation at 8 weeks following cycle 2. Post discussion at the Data and Safety Monitoring Board (DSMB) on May 25, 2021, the principal investigator (PI) and Committee voted to close the study to new patient enrollment prior to reaching accrual of 34 patients, secondary to lack of efficacy. In this study of patients with advanced MSS CRC, combination ONC201/nivolumab was well-tolerated; objective responses to ONC201/nivolumab were not observed.

Abstract 5492: Spatial organization and cellular composition of immunity hubs in human colorectal cancer

Abstract Background: Among colorectal cancer (CRC) tumors, mismatch repair deficient (MMRd) tumors have more immunogenic neo-antigens, hence more cytotoxic T-cell mediated anti-tumor immunity than mismatch repair proficient (MMRp) tumors. Previously1, we transcriptionally profiled over 300,000 cells from 62 MMRd and MMRp CRC tumors and found an MMRd-unique network of immunologically active transcriptional states enriched in interferon-stimulated genes (ISGs). With 4-color imaging, we showed that this program arises from spatially organized hubs of at least 3 cell types: IFNã-secreting T and interferon-responsive CXCL9/10/11+ myeloid and tumor cells. To characterize the breadth of cells involved in tumor immunity hubs, we must simultaneously measure the expression of 100s of genes in situ. Methods: To describe the cellular composition, structural organization and intercellular spatial interactions of these immunity hubs, we profiled primary untreated resection specimens from 17 CRC donors (n=12 MMRd, 5 MMRp) using multiplexed error-robust FISH (MERFISH) mRNA microscopy. Efforts were made to sample both the tumor body and the invasive border of the tumor. We designed a panel of 479 genes to capture key transcriptional programs from our single-cell atlas1. We wrote analytical pipelines to segment transcripts into cells, select high-quality cells, and organize cells into distinct zones in tissue. To leverage the rich information in the scRNA-seq atlas1, we designed a robust label transfer analysis to assign cell state labels to MERFISH cells by comparison to scRNAseq cells. Results: We profiled 7.5 million high quality MERFISH cells across 21 CRC tissue sections and labeled the cells into 7 major lineages: 63.19% epithelial, 22.52% stromal, 7.75% myeloid, 3.72% T/NK/ILCs, 1.45% plasma, 1.2% B, and 0.17% mast cells. We visualized the spatial location of these cell types. T cells aggregated into 3 distinct regions of tissue: tertiary lymphoid structures (TLS) outside the tumor, and smaller clusters near the invasive border and in the tumor center. We identified immunity hubs defined by colocalized CXCL9/10/11 expressing cells and T cells near the invasive border and in the center of MMRd tumors. As expected, we found enrichment of CXCL13, IFNG, and ISGs such as CD74 and MHCII genes at these locations. In contrast, we found evidence of CCL17+CCL19+LAMP3+ activated dendritic cells and B cells enriched in the TLS. These results support a distinct composition and localization of immunity hubs in tumors, in contrast to TLS outside tumors. Conclusions: Our study defines the composition, spatial organization, and intercellular interactions of immunity hubs, shedding light on the anti-tumor immune response in CRC. Ethics Approval: Approved by the DF/HCC Institutional Review Board (protocol #02-240).(1) Pelka, K. et al. Spatially organized multicellular immune hubs in human colorectal cancer. Cell 184, 4734-4752.e20 (2021) Citation Format: Mukta G. Palshikar, Maxwell Spurrell, Jack Demaray, Han Chen, Scott Engels, Roopa Madhu, Milan Parikh, Izabella Gazmora, Arnav Mehta, Nicolas Fernandez, Colles Price, Jiang He, Sonia Cohen, Karin Pelka, Nir Hacohen, Jonathan Chen, Ilya Korsunsky. Spatial organization and cellular composition of immunity hubs in human colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5492.

Abstract 6011: Pharmacological inhibition of PMS2 increases tumor mutational burden, induces microsatellite instability and elicits immune mediated rejection in vivo

Abstract Tumors carrying defects in DNA mismatch repair (MMR-d) display high tumor mutational burden (TMB) and increased tumor neoantigen levels. MMR-d leads to accumulation of single nucleotide variants (SNVs) and insertions or deletions (indels) amongst repetitive DNA sequences generating microsatellite instability (MSI). Cancers that harbor >40% microsatellite variations are described as MSI-high (MSI-H). These tumors display unique clinical features including better prognosis, increased immune infiltration and remarkable response to immune checkpoint blockade (ICB) therapy. Colorectal cancer (CRC) patients with MMR-d often respond to therapies based on immune checkpoint blockade, whilst those with mismatch repair proficient (MMR-p) tumors do not. Therefore, identifying strategies to enhance the efficacy of immunotherapeutic treatments and transform this prevalent subgroup of CRCs from immunologically cold to hot remains an urgent and an unmet clinical need. We discovered NP1867 a first-in-class, potent, selective, covalent small molecule inhibitor of the DNA Mismatch Repair protein PMS2. We show by biochemical, biophysical, and protein-ligand X-ray crystallographic methods that NP1867 binds irreversibly to the ATP binding site of the N-terminal ATPase domain of PMS2. NP1867 displays potent binding to PMS2 in a NanoBRET cellular target engagement assay and inhibits MMR activity in mechanistic and functional cell-based assays of MMR-dependent DNA repair. Continuous treatment of murine CRC cell line CT26 (MMR-p) with NP1867 increases TMB, specifically enriches gained mutations with typical MMR-d related COSMIC mutational signatures, and elicits MSI-H status in a time-dependent manner, demonstrating for the first time that inhibition of PMS2 with a small molecule phenocopies the inactivation of MMR observed in patients. Remarkably, inoculation of immune-competent mice with CT26 cells pre-treated with NP1867 elicits tumor regressions in anti-PD1-treated animals, recapitulating the unique clinical features of MMR-d/MSI-H tumors. Conversely, no response is observed in immune-competent animals inoculated with control-treated cells. The extent of in vivo response correlates with the duration of in vitro NP1867 treatment and with the MSI-H status of treated CT26 cells. In conclusion, small molecule NP1867 functionally inhibits DNA MMR by targeting PMS2, enriches gained mutations with MMR-d COSMIC signatures, elicits MSI-H status, and enhances immune surveillance in preclinical models. These findings pave the way for the development of orally bioavailable compounds suitable for long-term dosing in animal models. Citation Format: Eleonora Piumatti, Alexia Hervieu, Philippe Riou, Julian Blagg, Adam Peall, Sam Weeks, Maria T. Rodríguez-Plata, Giuseppe Rospo, Sasi Arunachalam, Bettina Meier, Paige Tongue, Tessa McLaren, Kalpesh Parmar, Pradip Patel, David Clark, Gareth Langley, Charles Nichols, Benoît Rousseau, Paul Winship, Matthew Baker, Martin Drysdale, Giovanni Germano, Alberto Bardelli. Pharmacological inhibition of PMS2 increases tumor mutational burden, induces microsatellite instability and elicits immune mediated rejection in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6011.

Efficacy and safety of PD-1 blockade plus long-course chemoradiotherapy in locally advanced rectal cancer (NECTAR): a multi-center phase 2 study

Adding PD-1 blockade in the neoadjuvant regimens for locally advanced rectal cancer (LARC) patients with microsatellite stable (MSS) / mismatch repair-proficient (pMMR) tumors is an attractive, but debatable strategy. This phase 2, multicenter, prospective, single-arm study enrolled patients from 6 centers from June 2021 to November 2022. Locally advanced rectal cancer (LARC, cT3-4aN0M0 and cT1-4aN1-2M0) patients aged ≥18 years with the distance from distal border of tumor to anal verge ≤10 cm (identified by Magnetic Resonance Imaging) were qualified for inclusion. The patients received long-course radiotherapy (50 Gy/25 fractions, 2 Gy/fraction, 5 days/week) and three 21-day cycles capecitabine (850–1000 mg/m2, bid, po, day1–14) and three 21-day cycles tislelizumab (200 mg, iv.gtt, day8) as neoadjuvant. Total mesorectal excision (TME) was 6–12 weeks after the end of radiotherapy to achieve radical resection. A total of 50 patients were enrolled in this study. The pathological complete response rate was 40.0% [20/50, 95% confidence interval (CI): 27.61–53.82%], while 15 (30.0%, 95% CI: 19.1–43.75%), 9 (18.0%, 95% CI: 9.77–30.8%), 2 (4.0%, 95% CI: 1.10–13.46%) patients respectively achieved grade 1, 2, and 3 tumor regression. Treatment-related adverse events (TRAEs) occurred in 28 (56.0%) LARC patients, including 26(52.0%) with grade I-II and 2 (4.0%) with grade III (1 with grade 3 immune-related colitis and 1 with grade 3 rash). PD-1 blockade plus long-course chemoradiotherapy (CRT) showed promising therapeutic effects according to pathological complete response rate and is well-tolerated in LARC patients. A larger randomized controlled study is desired to further validate the above findings.

The prognostic value of tumor budding in a thoroughly characterized stage II colon cancer population in the context of a national screening program

Tumor budding as a prognostic marker in colorectal cancer has not previously been investigated in a cohort of screened stage II colon cancer patients. We assessed the prognostic significance of tumor budding in a thoroughly characterized stage II colon cancer population comprising surgically resected patients in the Region of Southern Denmark from 2014 to 2016. Tumors were re-staged according to the 8th edition of UICC TNM Classification, undergoing detailed histopathological evaluation and tumor budding assessment following guidelines from the International Tumor Budding Consensus Conference. Prognostic evaluation utilized Kaplan-Meier curves, log-rank tests, and Cox proportional hazard models for time to recurrence (TTR), recurrence-free survival (RFS), and overall survival (OS).Out of 497 patients, 20% were diagnosed through the national colorectal cancer screening program. High-grade tumor budding (Bd3) was found in 19% of tumors and was associated with glandular subtype, perineural invasion, mismatch repair proficient tumors, and tumor recurrence (p < 0.001, p < 0.001, p = 0.045, and p = 0.007 respectively). In multivariable Cox regression, high-grade budding was a significant prognostic factor for TTR compared to low-grade (Bd3 HR 2.617; p = 0.007). An association between tumor budding groups and RFS was observed, and the difference was significant in univariable analysis for high-grade compared to low-grade tumor budding (Bd3 HR 1.461; p = 0.041). No significant differences were observed between tumor budding groups and OS.High-grade tumor budding is a predictor of recurrence in a screened population of patients with stage II colon cancer and should be considered a high-risk factor in a shared decision-making process when stratifying patients to adjuvant chemotherapy.

Combination of pembrolizumab and lenvatinib in second-line therapy for MSS/pMMR advanced endometrial cancer: literature review and a case report

Despite the existing standard treatments for endometrial cancer, the prognosis for these patients remained poor until recently. None of currently available cytostatics ensured long-term disease control and long-term survival of patients receiving standard platinum-based therapy. Poor treatment outcomes in patients with advanced endometrial cancer necessitated changes in therapeutic approaches and development of more effective treatment regimens. Better understanding of carcinogenesis mechanisms, emergence of a new molecular classification of endometrial cancer, and implementation of tailored treatment approaches based on tumor types led to a significant breakthrough in the treatment of advanced endometrial cancer. Currently, the most effective second-line therapy for endometrial cancer with high level microsatellite instability (MSI-h) or deficient mismatch repair system (dMMR) (25 % of cases), and no indications for surgery is pembrolizumab monotherapy. Most of cancers (about 75 %) are represented by microsatellite-stable and mismatch repair proficient tumors (MSS/рMMR). Patients with such tumors demonstrating disease progression after systemic therapy should receive a combinations of the immune checkpoint inhibitor pembrolizumab and the multi-targeted tyrosine kinase inhibitor lenvatinib. In this article, we review relevant literature and report a case of successful treatment of MSS/pMMR advanced endometrial cancer with a combination of pembrolizumab and lenvatinib as a second-line therapy (after disease progression in response to platinum-containing first-line chemotherapy), which ensured long-term disease control.

Context-dependent environmental associations with endometrial cancer histotype and genotype

ObjectiveMLH1 loss due to MLH1 methylation, detected during Lynch syndrome screening, is one of the most common molecular changes in endometrial cancer. It is well established that environmental influences such...

Facts and Hopes in Colorectal Cancer Immunotherapy.

Although a minority of colorectal cancers exhibit mismatch repair deficiency and associated sensitivity to immune checkpoint inhibitors (ICI), the vast majority of colorectal cancers arise in a tolerogenic microenvironment with mismatch repair proficiency, low tumor-intrinsic immunogenicity, and negligible immunotherapy responsiveness. Treatment strategies to augment tumor immunity with combination ICIs and chemotherapy have broadly failed in mismatch repair-proficient tumors. Similarly, although several small single-arm studies have shown that checkpoint blockade plus radiation or select tyrosine kinase inhibition may show improved outcomes compared with historical controls, this finding has not been clearly validated in randomized trials. An evolving next generation of intelligently engineered checkpoint inhibitors, bispecific T-cell engagers, and emerging CAR-T cell therapies may improve immunorecognition of colorectal tumors. Across these modalities, ongoing translational efforts to better define patient populations and biomarkers associated with immune response, as well as combine biologically sound and mutually amplifying therapies, show promise for a new era of immunotherapy in colorectal cancer.

Treatment with lenvatinib plus pembrolizumab in recurrent or advanced endometrial cancer: A systematic review and meta-analysis.

e17630 Background: Endometrial cancer (EC) is the second most prevalent gynecological cancer. After failure to first-line platinum-based chemotherapy, treatment options are sparse, but recent studies have investigated new approaches with promising results. We conducted a systematic review and meta-analysis to evaluate the efficacy and safety of Lenvatinib plus Pembrolizumab in patients with advanced or recurrent EC. Methods: PubMed, Web of Science, Cochrane, Scopus, and LILACS databases, Central Register of Clinical Trials, and congresses publication websites were searched for studies using Lenvatinib plus Pembrolizumab in advanced or recurrent EC with progression after platinum-based chemotherapy. Outcomes of interest were best overall response rate (BORR) and disease control rate (DCR), on intention-to-treat (ITT) and per-protocol analyses, and according to mismatch repair status. Progression free-survival (PFS) and overall survival (OS) were also assessed. Heterogeneity was examined with the Cochran Q test and I2 statistics. We use a DerSimonian and Laird random-effects model. Results: Four studies, with 637 patients, were included: two clinical trials and two retrospective observational cohorts. Endometrioid EC was the predominant histology (53%), and most patients had mismatch repair-proficient tumors (pMMR, 86.5%). In a pooled analysis, with a medium follow-up of 12.2 months, BORR was 31% (95%CI 26, 37), and DCR was 74% (95%CI 65, 83) on ITT. CR, PR, and SD were documented in 37 (5.8%),168 (26.3%) and 284 (44.5%) patients, respectively. BORR was 48% in microsatellite unstable tumors compared to 31% in stable microsatellite disease (p = 0.07), while DCR was similar in both groups (p = 0.33). Median progression-free survival was 7.2 months (95%CI 3.2, 7.4), and median overall survival was 18.3 months (95%CI 8.6, 18.3) in patients receiving Lenvatinib and Pembrolizumab. The most common treatment-related adverse events (AE) included diarrhea 277/514 (53.8%), nausea 244/514 (47.4%), hypothyroidism 288/562 (39.1%), hypertension 338/632 (36.9%), fatigue 213/632 (31.0%), and vomiting 178/514 (34.6%). Grades 3 or 4 AE was reported in 436/514 (79.6%) patients. Overall, dose reductions, treatment interruptions, and discontinuation due to toxicities were required in 61%, 63%, and 27% of patients, respectively. Conclusions: This systematic review and meta-analysis reinforce the antitumor activity of the combination of Pembrolizumab and Lenvatinib in patients with advanced or recurrent EC, regardless of MMR status. Despite high rates of serious adverse events related to treatment, most were manageable.

Acute inflammatory reaction during anti-angiogenesis therapy combined with immunotherapy as a possible indicator of the therapeutic effect: Three case reports and literature review.

The posterior line treatment of unresectable advanced or metastatic gastrointestinal (GI) tumors has always been a challenging point. In particular, for patients with microsatellite stable (MSS)/mismatch repair proficient (pMMR) 0GI tumors, the difficulty of treatment is exacerbated due to their insensitivity to immune drugs. Accordingly, finding a new comprehensive therapy to improve the treatment effect is urgent. In this study, we report the treatment histories of three patients with MSS/pMMR GI tumors who achieved satisfactory effects by using a comprehensive treatment regimen of apatinib combined with camrelizumab and TAS-102 after the failure of first- or second-line regimens. The specific contents of the treatment plan were as follows: apatinib (500 mg/d) was administered orally for 10 days, followed by camrelizumab (200 mg, ivgtt, day 1, 14 days/cycle) and TAS-102 (20 mg, oral, days 1-21, 28 days/cycle). Apatinib (500 mg/d) was maintained during treatment. Subsequently, we discuss the possible mechanism of this combination and review the relevant literature, and introduce clinical trials on anti-angiogenesis therapy combined with immunotherapy.

Epigenetic MMR defect identifies a risk group not accounted for through traditional risk stratification algorithms in endometrial cancer.

We sought to evaluate the contribution of mismatch repair (MMR) status to traditional risk stratification algorithms used to predict nodal involvement and recurrence in a large single-institution cohort. Endometrioid endometrial cancer (EC) cases from 2014-2020 were evaluated. MMR immunohistochemistry (IHC) was performed universally. Uterine factors assessed in the Mayo criteria were used to retrospectively classify patients as low or high risk for lymphatic spread. Patients were classified according to risk for recurrence using GOG 99 and PORTEC criteria. Associations were evaluated using chi-square and t-tests and contributing factors assessed using logistic regression models. 1,514 endometrioid EC were evaluated; 392 (25.9%) were MMR (MMR) deficient of which 80.4% of MMR defects were associated with epigenetic silencing of MLH1. Epigenetic MMR defects were significantly more likely to be high risk for lymph node (LN) metastasis based on Mayo criteria (74.9% vs 60.6%, p=<0.001) and with the presence of LN metastasis (20.3 vs 10.5%, p=0.003) compared to MMR proficient tumors. Tumors with epigenetic MMR defects were significantly more likely to be classified as high or high intermediate risk using GOG99 and PORTEC criteria. Furthermore, cases with epigenetic MMR defects classified as low or low intermediate risk were significantly more likely to recur (GOG99 p=0.013; PORTEC p=0.008) and independently associated with worse disease-free survival (DFS). MMR status was found to be independently associated with worse DFS (HR 1.90; 95% CI 1.34-2.70; p=0.003) but not overall survival. While MMR deficient EC has been associated with poor prognostic features in prior reports; we demonstrate that only epigenetic MMR defects have poorer outcomes. Epigenetic MMR defect were independently associated with lymph node metastasis after controlling for risk criteria. Epigenetic MMR deficiency was found to be an independent predictor of recurrence beyond the factors considered in traditional risk stratification algorithms. Traditional uterine-based risk stratification algorithms may not fully reflect the risk for recurrence in MMR deficient tumors. Consideration should be given to implementing MMR status and MLH1 hypermethylation alongside traditional risk stratification algorithms. Performing MMR IHC on preoperative pathologic specimens may aid in risk stratification and patient counseling.

Genetic and pharmacological modulation of DNA mismatch repair heterogeneous tumors promotes immune surveillance.

Patients affected by colorectal cancer (CRC) with DNA mismatch repair deficiency (MMRd), often respond to immune checkpoint blockade therapies, while those with mismatch repair-proficient (MMRp) tumors generally do not. Interestingly, a subset of MMRp CRCs contains variable fractions of MMRd cells, but it is unknown how their presence impacts immune surveillance. We asked whether modulation of the MMRd fraction in MMR heterogeneous tumors acts as an endogenous cancer vaccine by promoting immune surveillance. To test this hypothesis, we use isogenic MMRp (Mlh1+/+) and MMRd (Mlh1-/-) mouse CRC cells. MMRp/MMRd cells mixed at different ratios are injected in immunocompetent mice and tumor rejection is observed when at least 50% of cells are MMRd. To enrich the MMRd fraction, MMRp/MMRd tumors are treated with 6-thioguanine, which leads to tumor rejection. These results suggest that genetic and pharmacological modulation of the DNA mismatch repair machinery potentiate the immunogenicity of MMR heterogeneous tumors.

Colon cancer CT staging according to mismatch repair status: Comparison and suggestion of imaging features for high-risk colon cancer

BackgroundNeoadjuvant treatment with either chemotherapy or immunotherapy is gaining momentum in colon cancers (CC). To reduce over-treatment, increasing staging accuracy using computed tomography (CT) is of high importance. PurposeTo assess and compare CT imaging features of CC between mismatch repair-proficient (pMMR) and MMR-deficient (dMMR) tumours and identify CT features that can distinguish high-risk (pT3-4, N+) CC according to MMR status. MethodsPrimary staging CTs of 266 patients who underwent primary surgical resection of a colon tumour were retrospectively and independently evaluated by two radiologists. Logistic regression analysis was performed to identify significant associations between imaging features and positive lymph node status. Receiver operating characteristic (ROC) curves of significantly associated features were assessed and validated in an external cohort of 104 patients. ResultsAmong pT3 tumours only, dMMR CC were significantly larger than pMMR CC in both length and thickness (length 59.39 ± 26.28 mm versus 48.70 ± 23.72, respectively, p = 0.031; thickness 20.54 mm ± 11.17 versus 16.34 ± 8.73, respectively, p = 0.027). For pMMR tumours, nodal internal heterogeneity on CT was significantly associated with a positive lymph node status (odds ratio (OR) = 2.66, p = 0.027), while for dMMR tumours, the largest short diameter of the nodes was associated with lymph node status (OR = 2.01, p = 0.049). The best cut-off value of the largest short diameter of involved nodes was 10.4 mm for dMMR and 7.95 mm for pMMR. In the external validation cohort, AUCs for predicting involved nodes based on the largest short diameter was 0.764 for dMMR tumours using 10 mm size cut-off and 0.624 for pMMR tumours using 7 mm cut-off. ConclusionThese data show that CT imaging features of primary CC differ between dMMR and pMMR tumours, suggesting that the assessment of CT-based CC staging should take MMR status into consideration, especially for lymph node status, and thus may help in selecting patients for neoadjuvant treatment.

Effect of sentinel lymph node isolated tumor cells on recurrence free survival in patients with mismatch repair proficient vs. deficient stage I/II endometrioid endometrial adenocarcinoma (173)

Objectives: To assess associations between mismatch repair (MMR) status and recurrence-free survival (RFS) among early-stage endometrial cancer patients with and without isolated tumor cells (ITCs). Methods: We conducted a multi-institution, retrospective study of women with stage I/II endometrial cancer with endometrioid histology who underwent surgical staging with sentinel lymph node (SLN) mapping with or without completing the lymphadenectomy between 2016 and 2021. SLN mapping was performed following the NCCN SLN mapping guidelines. ITC patients and matched controls were identified through electronic medical records using keyword search. Patients were excluded if they had evidence of micro-or macro-metastases in any lymph node (LN). Categorical variables were analyzed using the Chi-square test and continuous variables were analyzed with Student’s t-test and the two-proportion Z-test. Kaplan–Meier method and log-rank tests were used for survival analysis. Results: Among 234 patients, 38 were found to have ITCs. The majority had grade 1 (82.1%), stage IA (67.0%), endometrioid adenocarcinoma. Overall, 22.2% of tumors were MMR deficient by immunohistochemistry. Patients with ITCs were more likely to demonstrate > 50% myometrial invasion (24.5% vs 52.5%, p=<0.001) and were more likely to receive adjuvant radiation therapy (14.8% vs 42.1%, p<0.001) and/or chemotherapy (2.6% vs 23.7%, p<0.001). Grade (p=0.923) and MMR status (p=0.850) were not significantly different between patients with ITCs and those with LN-negative disease. The Median follow-up time was 27 months. Overall, 11 patients we re diagnosed with recurrence (4.7%). The recurrence rate for patients with LN-negative disease was 4.6% (9/196) and the recurrence rate for ITC positive patients was 5.3% (2/38) (p=0.842). The 3-year RFS was 96% in patients with LN-negative disease and 88% in patients with ITC positive disease (log-rank p=0.712). Recurrence rates were comparable among patients with MMR proficient tumors, regardless of ITC status (LN-negative: 3.3% vs ITC-positive: 3.4%; p=0.975). This was also true among patients with MMR deficient tumors (LN-negative: 9.3% vs ITC-positive: 11.1%,p=0.175). RFS was not different between LN-negative and ITC-positive patients with MMR proficient tumors (log-rank p=0.846) as well as between LN-negative and ITC-positive patients with MMR deficient tumors (log-rank p=0.790). Conclusions: These preliminary data suggest that the presence of ITCs does not impact RFS in early-stage endometrial cancer patients with MMR proficient or MMR deficient tumors. However, a longer follow-up time and a larger sample size are needed to better explore the relationship between the presence of ITCs and tumor molecular characterization. Objectives: To assess associations between mismatch repair (MMR) status and recurrence-free survival (RFS) among early-stage endometrial cancer patients with and without isolated tumor cells (ITCs). Methods: We conducted a multi-institution, retrospective study of women with stage I/II endometrial cancer with endometrioid histology who underwent surgical staging with sentinel lymph node (SLN) mapping with or without completing the lymphadenectomy between 2016 and 2021. SLN mapping was performed following the NCCN SLN mapping guidelines. ITC patients and matched controls were identified through electronic medical records using keyword search. Patients were excluded if they had evidence of micro-or macro-metastases in any lymph node (LN). Categorical variables were analyzed using the Chi-square test and continuous variables were analyzed with Student’s t-test and the two-proportion Z-test. Kaplan–Meier method and log-rank tests were used for survival analysis. Results: Among 234 patients, 38 were found to have ITCs. The majority had grade 1 (82.1%), stage IA (67.0%), endometrioid adenocarcinoma. Overall, 22.2% of tumors were MMR deficient by immunohistochemistry. Patients with ITCs were more likely to demonstrate > 50% myometrial invasion (24.5% vs 52.5%, p=<0.001) and were more likely to receive adjuvant radiation therapy (14.8% vs 42.1%, p<0.001) and/or chemotherapy (2.6% vs 23.7%, p<0.001). Grade (p=0.923) and MMR status (p=0.850) were not significantly different between patients with ITCs and those with LN-negative disease. The Median follow-up time was 27 months. Overall, 11 patients we re diagnosed with recurrence (4.7%). The recurrence rate for patients with LN-negative disease was 4.6% (9/196) and the recurrence rate for ITC positive patients was 5.3% (2/38) (p=0.842). The 3-year RFS was 96% in patients with LN-negative disease and 88% in patients with ITC positive disease (log-rank p=0.712). Recurrence rates were comparable among patients with MMR proficient tumors, regardless of ITC status (LN-negative: 3.3% vs ITC-positive: 3.4%; p=0.975). This was also true among patients with MMR deficient tumors (LN-negative: 9.3% vs ITC-positive: 11.1%,p=0.175). RFS was not different between LN-negative and ITC-positive patients with MMR proficient tumors (log-rank p=0.846) as well as between LN-negative and ITC-positive patients with MMR deficient tumors (log-rank p=0.790). Conclusions: These preliminary data suggest that the presence of ITCs does not impact RFS in early-stage endometrial cancer patients with MMR proficient or MMR deficient tumors. However, a longer follow-up time and a larger sample size are needed to better explore the relationship between the presence of ITCs and tumor molecular characterization.

Cost-effectiveness analysis of tumor molecular testing in stage III endometrial cancer (089)

<b>Objectives:</b> Treatment of advanced and recurrent endometrial cancer (EC) has traditionally been based on factors, such as histology and stage. Recent studies suggest that tumor molecular profiles may predict treatment outcomes and guide treatment choice. For example, pembrolizumab (PMB) use in patients with mismatch repair deficient (MMRd) tumors versus combined pembrolizumab and lenvatinib (PL) in patients with mismatch repair proficient tumors (MMRp). Furthermore, <i>POLE</i> mutated (<i>POLE</i>mut) tumors demonstrate a favorable prognosis even with minimal treatment. Prospective trials using molecular profiling for treatment assignment are ongoing, but tumor molecular testing (TMT) is costly and time-consuming. We, therefore, sought to evaluate the cost-effectiveness of TMT in stage III EC. <b>Methods:</b> A Markov decision model was created to compare two testing strategies in patients with stage III EC: TMT versus no testing (NT). TMT patients had sequential <i>POLE</i> next-generation sequencing (NGS), mismatch repair (MMR) immunohistochemistry (IHC), and p53 IHC. Adjuvant therapies included radiation (RT) alone for <i>POLE</i>mut and chemoradiation (CTRT) for NT, MMRd, p53 mutated (p53mut), and no specific molecular profile (NSMP) using PORTEC-3 data. All patients received six cycles of carboplatin and paclitaxel (CP) for first recurrence using GOG 209 outcomes. MMRd patients received PMB alone for the second recurrence, whereas all other patients received PL. National database and registry values, literature review, and expert input were used for cost and utility values. A healthcare payer perspective, willingness-to-pay (WTP) threshold of $100,000, and 5-year time horizon were used. Data analysis was done with TreeAge Pro Software 2021. Outcomes were reported in quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICERs). Sensitivity analyses tested model robustness, and a structural sensitivity analysis was performed in which controls underwent MMR IHC alone. <b>Results:</b> Compared to NT, TMT was less costly and more effective. While the model was most sensitive to median overall survival with PL, probability of MMRd status, and cost of lenvatinib, TMT remained cost-saving over all parameters tested. On Monte Carlo analysis, TMT was favored in 79% and 80% of iterations with a WTP of $50,000 and $100,000, respectively. When controls had MMR IHC alone, TMT was no longer cost-effective with an incremental cost of $3100 and incremental effectiveness of 0.017 QALYs, or $184,942/QALY gained. <b>Conclusions:</b> For patients with stage III EC, this model suggests TMT is associated with cost savings compared to NT. However, when compared to MMR IHC alone, a common clinical approach, TMT was no longer a cost-effective strategy at a WTP threshold of $100,000. Further prospective studies are needed to determine the prognostic value of molecular profiles in endometrial cancer. It will be essential to continue assessing the cost-effectiveness of these molecular tests as new data becomes available.

Abstract 5135: Antitumor activity of dostarlimab by PD-L1 and tumor mutation burden (TMB) in patients (pts) with mismatch repair deficient and proficient (dMMR and MMRp) tumors in the GARNET trial

Abstract Background: Dostarlimab is a programmed death 1 (PD-1) inhibitor approved as monotherapy in pts with dMMR recurrent/advanced endometrial cancer (EC) that has progressed on or following treatment with a platinum-containing regimen or solid tumors that have progressed on or following prior treatment, with no satisfactory alternative treatment options. Here we report on a post-hoc analysis of antitumor activity by PDL1 expression and TMB in pts with dMMR and MMRp solid tumors in the GARNET trial. Methods: GARNET (NCT02715284) is a phase 1, multicenter, open-label, single-arm study of dostarlimab in pts with advanced/recurrent solid tumors. Three expansion cohorts enrolled pts based on MMR status: dMMR (A1) and MMRp (A2) advanced/recurrent EC, and dMMR non-EC solid tumors (F). Pts received dostarlimab 500 mg IV Q3W for 4 cycles, then 1000 mg IV Q6W until progression or discontinuation. TMB and PDL1 were exploratory biomarkers. TMB status was determined by Foundation One test; TMB-high (TMB-H) was defined as ≥10 mutations/Mb. PDL1 expression was determined by combined positive score (CPS) by Ventana assay; PDL1-high (PDL1-H) was defined as CPS ≥1. The study was not powered to assess antitumor activity within subgroups. Results: TMB-H and PDL1-H were common in dMMR solid tumors; PDL1-H was observed in 39.4% of MMRp EC tumors (Table). Objective response rate (ORR) was higher in pts with TMB-H/PDL1-H tumors (55.6% for all cohorts, combined; Table). Safety for each cohort was previously reported.1 Conclusions: PDL1-H and TMB-H were frequently observed in the dMMR EC and non-EC cohorts, regardless of tumor type; PDL1-H was also prevalent in MMRp EC tumors. Although not powered to assess antitumor activity, ORR by BICR per RECIST v1.1 was higher in pts with TMB-H and PDL1-H solid tumors. Across cohorts, dMMR status was predictive of response. 1.Andre T, et al. Ann Oncol 2021;32(suppl 5):S829-S866. 991P. Table A1(dMMR EC)N=103 F(dMMR non-EC)N=106 A1+F(dMMR combined)N=209 A2(MMRp EC)N=142 A1+A2+F (Total)N=351 Biomarker distribution, n (%) TMB High 85 (82.5) 79 (74.5) 164 (78.5) 9 (6.3) 173 (49.3) Low 13 (12.6) 9 (8.5) 22 (10.5) 129 (90.8) 151 (43.0) Unknown 5 (4.9) 18 (17.0) 23 (11.0) 4 (2.8) 27 (7.7) PD-L1 High 56 (54.4) 52 (49.1) 108 (51.7) 56 (39.4) 164 (46.7) Low 23 (22.3) 17 (16.0) 40 (19.1) 45 (31.7) 85 (24.2) Unknown 24 (23.3) 37 (34.9) 61 (29.2) 41 (28.9) 102 (29.1) ORR by BICR per RECIST v1.1, n/N (%, 95% CI)a Overall 46/103(44.7, 34.9–54.8) 41/106(38.7, 29.4–48.6) 87/209(41.6, 34.9–48.6) 19/142(13.4, 8.3–20.1) — TMB-L/PDL1-L (L/L) 1/5(20.0, 0.5–71.6) 1/3 (33.3, 0.8–90.6) 2/8(25.0, 3.2–65.1) 2/43(4.7, 0.6–15.8) 4/51(7.8, 2.2–18.9) TMB-L/PDL1-H (L/H) 2/5(40.0, 5.3–85.3) 1/2(50.0, 1.3–98.7) 3/7(42.9, 9.9–81.6) 7/50(14.0, 5.8–26.7) 10/57(17.5, 8.7–29.9) TMB-H/PDL1-L (H/L) 5/17(29.4, 10.3–56.0) 3/14(21.4, 4.7–50.8) 8/31(25.8, 11.9–44.6) 0/1(0, 0–97.5) 8/32(25.0, 11.5–43.4) TMB-H/PDL1-H (H/H) 29/50(58.0, 43.2–71.8) 22/43(51.2, 35.5–66.7) 51/93(54.8, 44.2–65.2) 4/6(66.7, 22.3–95.7) 55/99(55.6, 45.2–65.5) aOnly those pts with both known TMB status and known CPS were included in ORR calculations Citation Format: Thierry André, Susana Banerjee, Dominique Berton, Susan L. Ellard, Begoña Jimenez, Vanessa Samouëlian, Lucy Gilbert, Valentina Boni, Xinwei Han, Grace Antony, Jennifer Veneris, Ana Oaknin. Antitumor activity of dostarlimab by PD-L1 and tumor mutation burden (TMB) in patients (pts) with mismatch repair deficient and proficient (dMMR and MMRp) tumors in the GARNET trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5135.

Abstract CT021: PD-1 blockade in solid tumors with defects in polymerase epsilon

Abstract Context: Polymerase epsilon (POLE) gene missense hotspot mutations can generate pathogenic (p) proofreading defects resulting in hypermutated genomic profiles. Aim: Determine the prevalence, genomic consequences and immunotherapy sensitivity of advanced POLE mutated tumors according to mutation site, primary tumor and tumor mutational burden (TMB). Results: Pan-Cancer TCGA &amp; MSKCC databases genomic analyses found a prevalence of non-pathogenic POLE mutations (POLEnp) of 3.4% with median TMB of 11 mutations/Megabase (mt/Mb, IQR 3-34). Pathogenic POLE mutations (POLEp) prevalence was 0.4% with median TMB of 215 mt/Mb (IQR 107-324), predominantly in colorectal and endometrial cancers. Prevalence dropped to 0.1% in metastatic cancers. We assessed prospectively the efficacy of PD-1 blockade in mismatch repair proficient advanced solid tumors harboring POLE missense mutations (phase II ASCe Nivolumab trial; NCT03012581). Variants were categorized prospectively by a molecular board as POLEp, POLEnp or Variants with Unknown significance (VUS). The primary endpoint was the Overall Response Rate (ORR) at 12 weeks according to RECIST 1.1, and secondary endpoints included survival analyses according to POLE variants pathogenicity. Among 61 screened patients, 21 were eligible and 20 received Nivolumab and 19 were assessable for response (table 1). The 12-week ORR was 37% for patients harboring POLEp and VUS and resulted in major survival improvement compared to POLEnp patients (HR=0.1 ; CI95% 0.02-0.7); see results in Table 1. Among patients POLEp tumors, while higher TMB was not predictive of response, higher proportion of POLE-related mutational signature correlated with improved benefit. In silico exonucleasic POLE domain analyses confirmed that all POLEp and 2 VUS clustered in the DNA binding or the Catalytic site. Recategorizing the VUS according to the location within the exonucleasic domain improved the prediction of survival outcomes. Impact: This study gives new insights on how DNA repair defects, mutational burden and signatures sensitize to PD-1 blockade and may offer emerging tumor agnostic biomarkers for benefit to checkpoint blockade. POLE variant pathogenicity All(N=21) POLEnp(N=5) VUS(N=4) POLEp(N=12) Age, years ± SD 57 ± 16 64 ± 10 56 ± 16 54 ± 17 Sex, Male (%) 12 (57) 5 (100) 2 (50) 5 (42) PS (ECOG)=1 (%) 16 (75) 4 (80) 2 (50) 10 (83) Primary tumor Colorectal 9 (43) 2 (40) 2 (50) 5 (42) Endometrial 6 (29) 0 (0) 0 (0) 6 (50) Gastric 2 (9) 2 (40) 0 (0) 0 (0) Glial 1 (5) 0 (0) 0 (0) 1 (8) Biliary tract 1 (5) 0 (0) 1 (25) 0 (0) Pancreas 2 (9) 1 (20) 1 (25) 0 (0) Number of previous treatments 2.4 ± 2 5 ± 2 1.8 ± 1 1.5 ± 1 TMB (mt/Mb, Min-Max)(N=16) 36.2 (2-385) 5 (4-9) 3 (2-4) 114 (25-385) ORR at 12 weeks (CR+PR) 37%(N=7/19) 0%(N=0/5) 50%(N=2/4) 46%(5/10) DCR at 12 weeks (CR+PR+SD) 58%(N=11/19) 0%(N=0/5) 75%(N=3/4) 80%(8/10) Median Progresssion-Free survival (months) 5.6 2.3 10.3vs POLEnp: HR=0.2 IC95% 0.1-0.7 Median Overall Survival (months) 9.1 5.0 Not Reachedvs POLEnp:HR=0.1 IC95% 0.02-0.7 Citation Format: Benoît Rousseau, Ivan Bieche, Eric Pasmant, Nadim Hamzaoui, Nicolas Leulliot, Lucas Michon, Aurelien de Reynies, Mike Foote, Julien Masliah-Planchon, Magali Svrcek, Romain Cohen, Victor Simmet, Paule Augereau, David Malka, Antoine Hollebecque, Damien Pouessel, Carlos Gomez-Roca, Rosine Guimbaud, Amandine Bruyas, Marielle Guillet, Muriel Duluc, Sophie Cousin, Christelle de la Fourchardiere, Frederic Rolland, Sandrine Hiret, Esma Saada-Bouzid, Olivier Bouche, Thierry Andre, Diane Pannier, Farid El Hajbi, Stephane Oudard, Christophe Tournigand, Jean-Charles Soria, Drew Gerber, Dennis Stephens, Michelle Lamandola-Essel, Steven B Maron, Bill Diplas, Guillem Argiles, Asha Krishnan, Neil Segal, Andrea Cercek, Nathalie Hoog-Labouret, Frederic Legrand, Clotide Simon, Assia Lamrani-Ghaouti, Luis A. Diaz, Pierre Saintigny, Sylvie Chevret, Aurelien Marabelle. PD-1 blockade in solid tumors with defects in polymerase epsilon [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT021.

Comprehensive profiling of clock genes expression in colorectal cancer (CRC).

3129 Background: Disruption of the circadian clock has been linked to cancer risk, development and progression. Core clock proteins are emerging as novel therapeutic targets in cancer. We previously showed that polymorphisms in clock genes were associated with anti-VEGF treatment outcome in metastatic CRC. Here we further evaluated the molecular landscape of clock pathway alterations in CRC. Methods: 7591 CRC tested at Caris Life Sciences (Phoenix, AZ) with WTS (Illumina NovaSeq) and NextGen DNA sequencing (NextSeq, 592 Genes and NovaSEQ, WES) were analyzed. Clock gene Score (CS) was determined using expression of core clock genes Z scores (positives of CLOCK, ARNTL, RORA/B/C and negatives of repressors CRY1/2, PER1/2/3, REVERBA/B) stratified by quartiles. xCell was used to quantify cell infiltration in the tumor microenvironment (TME). Consensus molecular subtypes (CMS) were assessed by RNAseq. Significance was determined as P-values adjusted for multiple testing ( q) of &lt;.05. Real world survival was obtained from insurance claims data and Kaplan-Meier estimates were calculated for comparison. Results: CS was higher in primary tumors than metastases and in right- than left-sided CRC ( P &lt;.001). Liver metastases were associated with lower CS (23% Q1 vs 19% Q4, P &lt;.001). CS was positively associated with CMS1 and 3 (21 vs 11% and 23 vs 9%, respectively, Q4 vs Q1) and negatively correlated with CMS2 and 4 (22 vs 32% and 34 vs 48%) (all P &lt;.001). These associations were confirmed in mismatch repair proficient (pMMR) tumors. Overall, TMB-H and dMMR/MSI-H were positively associated with CS (11 vs 6% and 8 vs 4%, Q4 vs Q1, q &lt;.0001) and PD-L1 showed a similar trend ( P &lt;.01, q =.06); the association with TMB-H was not significant in pMMR. High CS was associated with alterations of genes in WNT signaling, RAS, PI3K, TGF-β, and NOTCH pathways, while negatively associated with TP53 mutations, HER2 expression and CDX2 copy numbers, confirmed in pMMR (all q &lt;.05). CS negatively correlated with the angiogenesis pathway signature (Q1 vs Q4 Z score: 6.6 vs -4.6, P &lt;.001). B cells, M1 and M2 macrophages, neutrophils, NK, Tregs, CD4+ and CD8+ T cells, and myeloid dendritic cells were more abundant in the TME of tumors with high CS while cancer associated fibroblasts were lower, regardless of MMR status (all q &lt;.001). Individually, ARNTL tumor expression below median was associated with better OS (overall: HR 0.88, 95% CI [0.82-0.94]; pMMR: HR 0.88 [0.81-0.94]) and longer time on treatment of bevacizumab (overall: HR 0.91 [0.83-0.99]; pMMR: HR 0.91 [0.83-0.99]). Conclusions: This is the most extensive profiling study to investigate the expression of clock genes in CRC. Our data show that clock genes expression is strongly associated with distinct molecular features, immune cell infiltration, angiogenesis pathway enrichment and patient outcomes. These findings support the clock pathway as a therapeutic target in CRC, with a major role in CRC biology and TME modulation.

PD-1 Blockade in Solid Tumors with Defects in Polymerase Epsilon.

POLE proofreading deficiency leads to high tumor mutational burden with high tumor-infiltrating lymphocytes and predicts anti-PD-1 efficacy in mismatch repair-proficient tumors. Conversely, tumors harboring POLE mutations not affecting proofreading derived no benefit from PD-1 blockade. POLE proofreading deficiency is a new tissue-agnostic biomarker for cancer immunotherapy. This article is highlighted in the In This Issue feature, p. 1397.

Real-world experience of pembrolizumab and lenvatinib in recurrent endometrial cancer: A multicenter study in Korea

ObjectiveTo investigate the effectiveness and safety of pembrolizumab and lenvatinib (PEMBRO+LEN) for recurrent endometrial cancer (EC) in a real-world setting. MethodsThis multicenter retrospective cohort study included patients with recurrent EC who received PEMBRO+LEN between March 2020 and May 2021 at three tertiary hospitals in Korea. We summarized patient characteristics and evaluated the response rates, survival outcomes, and treatment-related adverse events (AEs). ResultsIn total, 48 patients were included in the study. The median age of the patients was 62.5 (range, 42–78) years. The most common histologic subtype was endometrioid adenocarcinoma (43.8%), followed by serous adenocarcinoma (25.0%). Most patients (91.7%) had mismatch repair-proficient tumors. Patients received PEMBRO+LEN for a median of 4.5 cycles, during which the best objective response rate and disease control rate were 23.8% (95% CI, 11.9–38.1) and 76.2% (95% CI, 61.9–88.1), respectively. Overall, 56.2% of patients experienced LEN dose reduction once or more and 16.7% experienced LEN interruption. The most common treatment-related AEs were fatigue (18.8%), hypertension (16.7%), and hypothyroidism (14.6%). Total of 8 patients (16.7%) discontinued LEN during the treatment because of treatment-related AEs. Serum CA-125 level was the only prognostic factor for progression-free survival (adjusted hazard ratio, 4.41; 95% confidence interval, 1.19–16.36; p = 0.03). ConclusionsIn our real-world study, Korean patients with recurrent EC who received PEMBRO+LEN showed lower treatment response rate and similar treatment discontinuation rate, compared to clinical trials.