Archival Tumor Research Articles

Oncogenic mutations in the TP53 and PI-3 kinase/AKT pathway are independent predictors of survival for advanced thyroid cancer: Analysis from the Molecular Screening and Therapeutics (MoST) program

BackgroundThyroid cancers with mutations in the phosphatidylinositol-3 kinase/AKT pathway have a poorer prognosis. However, knowledge about the relationship between histology, mutation profile, and outcomes is still developing. This study assessed the prognostic value of genomic profiles for patients with advanced thyroid cancer who experienced progression on conventional treatment. MethodsPatients recruited to a national clinical oncology program for treatment-refractory locally advanced, recurrent or metastatic cancers were analyzed. Patients' archival tumor samples underwent comprehensive genomic profiling. Specific oncogenic mutations and the presence of cancer related pathways were correlated with overall survival. ResultsFrom 2018 to 2021, 4,955 patients were recruited, with 44 (0.9%) having a diagnosis of thyroid cancer with 4 medullary and the remaining follicular derived: 17 differentiated, 13 poorly differentiated, and 10 anaplastic thyroid cancers. Of the 40 follicular-derived thyroid cancer samples, 17 (42.5%) carried TP53 mutations, followed by 11 with BRAF V600E (27.5%), 9 with NRAS (22.5%), 9 with mutations in the phosphatidylinositol-3 kinase/AKT pathway (22.5%), and 7 with TERT promoter mutations (17.5%). Both TP53 and phosphatidylinositol-3 kinase/AKT pathway alterations were associated with reduced overall survival (hazard ratio, 5.19; 95% confidence interval, 1.59–16.70, P = .02 and hazard ratio, 10.12; 95% confidence interval, 1.61–63.76, P = .01). Cox regression showed histologic type anaplastic thyroid cancer (hazard ratio, 12.93, P = .004), poorly differentiated thyroid cancer (hazard ratio, 5.19, P = .039), and TP53 and/or phosphatidylinositol-3 kinase/AKT pathway mutations (hazard ratio, 4.73, P = .017) were independently associated with overall survival. ConclusionTP53 and/or phosphatidylinositol-3 kinase/AKT pathway mutations correlated with overall survival independently of histotype in patients with advanced thyroid cancer. Comprehensive genomic profiling has potential to inform prognosis, as well as identifying treatment targets for patients with advanced thyroid cancer.

MTAP and p16 IHC as Markers for CDKN2A/B Loss in Meningiomas.

Homozygous cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B) loss is one of the parameters that support the designation of meningiomas as Central Nervous System (CNS) WHO grade 3 tumors. Evaluation of CDKN2A/B by sequencing or Fluorescence in situ hybridization (FISH) is costly and not always readily accessible. An immunohistochemistry (IHC)-based marker for the evaluation of CDKN2A/B loss would provide faster results at a lower cost. This retrospective study included patients diagnosed with meningioma at our institution between 2016 and 2019. Archival tumor tissue was used for analysis. MTAP immunohistochemistry (IHC) was performed at various dilutions (1:1200, 1:400, 1:200, 1:100) using two different antibodies, and p16 IHC was conducted simultaneously. These analyses were carried out at two different institutions. To determine the sensitivity and specificity of MTAP and p16 as surrogate markers for CDKN2A/B loss, CDKN2A FISH was utilized as the gold standard. Overall, 46/49 tumors showed strong MTAP staining (94%) at institution 1, and 44/49 (90%) showed either faint positive or positive results at institution 2. One grade 3 meningioma that demonstrated homozygous CDKN2A loss by FISH also showed loss of MTAP expression by IHC. One grade 2 meningioma showed regional CDKN2A loss by FISH and variable MTAP expression under different IHC conditions. MTAP expression evaluation was superior at a dilution of 1:100 with the Abnova Anti-MTAP Monoclonal antibody. P16 expression was variable and did not correlate with either MTAP expression or CDKN2A FISH results. MTAP IHC is a promising surrogate marker for the evaluation of CDKN2A status in meningiomas.

Abstract C089: Characterization of the breast tumor immune microenvironment in women of African descent using single-nucleus RNA- and ATAC-sequencing

Abstract Women of African descent are at an increased risk of developing and dying from aggressive subtypes of breast cancer. A connection between aggressive disease and Western Sub-Saharan African ancestry has been postulated, but it remains largely unknown to what extent breast cancer in Africa is reminiscent of breast cancer in U.S. African American (AA) women who experience disproportionately high mortality rates. We performed ATAC- and RNA-sequencing on 9 human triple-negative breast cancer cell lines of U.S. origin and discovered that African ancestry influences the chromatin landscape, leading to disparate transcription factor (TF) activity and downstream gene expression patterns indicative of an aggressive tumor biology. Here, we describe an ambitious study that employs single-nucleus (sn) ATAC- and RNA-sequencing (snMultiome) of frozen breast tumors to characterize chromatin accessibility and gene expression patterns with single-cell resolution in AA (n=33), Kenyan (n=25), and European American (EA, n=24) women in relation to genetic ancestry, risk factor exposures, clinical characteristics, and 5-year survival. To achieve this, we successfully isolated intact, high-quality single nuclei from archival frozen breast tumor tissue through an optimized combination of enzymatic digestion and automated tissue homogenization. We performed snMultiome sequencing of 82 tumors using the 10x Genomics platform. Following filtering, normalization (SCT for snRNA; LSI for snATAC), peak calling (MACS2), and integration (Harmony), our dataset includes a total of 296,557 nuclei. Cancerous (163,419 nuclei) and non-cancerous (133,138 nuclei) cells were distinguished based on DNA copy number (CopyKat). Within the microenvironment, 11 major immune, epithelial, and stromal cell types were successfully annotated, exhibiting distinct patterns by population group (e.g. AA tumors showed markedly increased abundance of myeloid and T-cells, while Kenyan tumors showed increased abundance of pericytes and fibroblasts, relative to EA). A large number of enriched TFs within each cell type varied significantly by population group, suggesting distinct chromatin accessibility patterns related to genetic ancestry. CD45+, EPCAM- cells were further extracted, clustered, and manually annotated for subpopulations based on known marker genes. We detected 26 distinct immune subpopulations across our samples, including 2 inflammatory macrophage, 6 immunosuppressive macrophage, 1 fibronectin+/thrombospondin+ monocyte, 6 T-cell, 1 natural killer cell, 2 B-cell, 1 mast cell, and 4 dendritic cell subpopulations. Differential gene expression analyses of each immune cell subpopulation, adjusted for age, BMI, and tumor subtype, revealed ancestry-specific gene expression patterns, which could provide novel insights into functional differences that may impact tumor immune response. Current efforts focus on in-depth molecular characterization of ancestry-related differences in the tumor immune environment and distinct signatures present in lethal disease. Citation Format: Alexandra R. Harris, Huaitian Liu, Brittany D. Jenkins, Tiffany H. Dorsey, Francis Makokha, Shahin Sayed, Gretchen Gierach, Stefan Ambs. Characterization of the breast tumor immune microenvironment in women of African descent using single-nucleus RNA- and ATAC-sequencing [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C089.

Safety and clinical activity of JNJ-78306358, a human leukocyte antigen-G (HLA-G) x CD3 bispecific antibody, for the treatment of advanced stage solid tumors

BackgroundJNJ-78306358 is a bispecific antibody that redirects T cells to kill human leukocyte antigen-G (HLA-G)-expressing tumor cells. This dose escalation study evaluated the safety, pharmacokinetics, pharmacodynamics, and preliminary antitumor activity of JNJ-78306358 in patients with advanced solid tumors.MethodsAdult patients with metastatic/unresectable solid tumors with high prevalence of HLA-G expression were enrolled. Dose escalation was initiated with once-weekly subcutaneous administration with step-up dosing to mitigate cytokine release syndrome (CRS).ResultsOverall, 39 heavily pretreated patients (colorectal cancer: n = 23, ovarian cancer: n = 10, and renal cell carcinoma: n = 6) were dosed in 7 cohorts. Most patients (94.9%) experienced ≥ 1 treatment-emergent adverse events (TEAEs); 87.2% had ≥ 1 related TEAEs. About half of the patients (48.7%) experienced CRS, which were grade 1/2. Nine patients (23.1%) received tocilizumab for CRS. No grade 3 CRS was observed. Dose-limiting toxicities (DLTs) of increased transaminases, pneumonitis and recurrent CRS requiring a dose reduction were reported in 4 patients, coinciding with CRS. No treatment-related deaths reported. No objective responses were noted, but 2 patients had stable disease > 40 weeks. JNJ-78306358 stimulated peripheral T cell activation and cytokine release. Anti-drug antibodies were observed in 45% of evaluable patients with impact on exposure. Approximately half of archival tumor samples (48%) had expression of HLA-G by immunohistochemistry.ConclusionJNJ-78306358 showed pharmacodynamic effects with induction of cytokines and T cell activation. JNJ-78306358 was associated with CRS-related toxicities including increased transaminases and pneumonitis which limited its dose escalation to potentially efficacious levels.Trial registration number ClinicalTrials.gov (No. NCT04991740).

Kinetic Profiling of RAS Mutations With Circulating Tumor DNA in the Canadian Cancer Trials Group CO.26 Trial Suggests the Loss of RAS Mutations in Neo-RAS-Wildtype Metastatic Colorectal Cancer Is Transient.

In metastatic colorectal cancer (mCRC), RAS mutations drive resistance to anti-epidermal growth factor receptor antibodies. It is unclear whether RAS mutations ever become clonally undetectable. CO.26 was a phase II clinical trial that assessed durvalumab + tremelimumab in heavily pretreated mCRC. RAS mutation status was tracked over time using circulating tumor DNA (ctDNA) sequencing at baseline, week 8, and on progression. Among the 95 patients with KRAS/NRAS mutations in their archival tumor tissue, 6.3% (6/95) had undetectable RAS mutations in ctDNA collected at baseline or week 8 of the CO.26 study. Of these, 67% (4/6) of disappearances were transient, with the same mutation reappearing with progressive disease. In three cases, the simultaneous persistence of other preexisting CRC-associated truncal mutations could not be demonstrated, suggestive of low tumor shedding of ctDNA, leaving the incidence of true clonal reversion to RAS-wildtype (WT) possibly as low as 3.2% (3/95). Fewer patients in the neo-RAS-WT group (33%) had greater than four lesions at trial baseline compared with patients with persistent RAS mutations (75%), P = .046. The likelihood of synchronous metastases at cancer diagnosis (33% v 63%; P = .15) or liver metastases at trial baseline (50% v 68.5%; P = .17) was not significantly different between patients with disappearing versus persistent RAS mutations. Overall survival from stage IV diagnosis (hazard ratio, 0.77 [95% CI, 0.35 to 1.72]; P = .52) was not significantly different between those with disappearing versus persistent RAS mutations. The disappearance of RAS mutations was not associated with primary tumor sidedness (P = .41), archival BRAF/MEK/ERK-mutant status (P = .16/1.00/.09), nor baseline ctDNA HER2 amplifications (P = 1.00). We identified a 3.2%-6.3% prevalence of the neo-RAS-WT phenomenon in the CO.26 trial. However, 67% of apparent cases were transient with subsequent re-emergence.

Sacituzumab Govitecan Demonstrates Efficacy across Tumor Trop-2 Expression Levels in Patients with Advanced Urothelial Cancer.

Human trophoblast cell surface antigen 2 (Trop-2) is a protein highly expressed in urothelial cancer (UC). Sacituzumab govitecan (SG) is a Trop-2-directed antibody drug conjugate with a hydrolysable linker and a potent SN-38 payload. This study explored Trop-2 expression in tumors treated with SG in cohorts 1 to 3 (C1-3) from the TROPHY-U-01 study and evaluated whether efficacy was associated with Trop-2 expression. TROPHY-U-01 (NCT03547973) is an open-label phase II study that assessed the efficacy and safety of SG (alone or in combinations) in patients with unresectable locally advanced or metastatic UC (mUC). Archival tumor samples collected at enrollment for C1-3 were analyzed for Trop-2 membrane expression by considering histological scores (H-scores; scale 0-300) and the percentage of membrane positive tumor cells at low magnification (4×). The association of Trop-2 with clinical endpoints [objective response rate (ORR), progression-free survival (PFS), and overall survival (OS)] was evaluated. In C1-3, tissue was collected from 158 (82%) of 192 treated patients, and 146 (76%) had evaluable Trop-2 data. Trop-2 was highly expressed in tumor samples. The median [interquartile range (IQR)] Trop-2 H-score was 215 (180-246), and the median (IQR) percentage of membrane positive tumor cells was 91% (80-98). Trop-2 expression at any level was observed in 98% of patients. Furthermore, ORR, PFS, and OS benefits were observed across all Trop-2 expression levels. Trop-2 protein is highly expressed in UC, as confirmed by examining tumors from patients enrolled in the TROPHY-U-01 trial. The results indicate that SG demonstrates efficacy in mUC across Trop-2 expression levels.

Efficacy and Safety of Sacituzumab Govitecan in Patients With Advanced Solid Tumors (TROPiCS-03): Analysis in Patients With Advanced Endometrial Cancer.

Patients with advanced endometrial cancer (EC) who progress on or after platinum-based therapy and immunotherapy have poor prognosis. We report efficacy and safety of sacituzumab govitecan (SG), a trophoblast cell-surface antigen 2 (Trop-2)-directed antibody-drug conjugate, in patients with advanced EC. TROPiCS-03 (ClinicalTrials.gov identifier: NCT03964727) is a multicohort, open-label, phase II basket study in patients with metastatic solid tumors. Eligible patients in the EC cohort received SG 10 mg/kg once on days 1 and 8 every 3 weeks. Primary end point was objective response rate (ORR) by investigator's assessment per RECIST v1.1. Secondary end points included clinical benefit rate (CBR; complete and partial response, and stable disease ≥6 months), duration of response (DOR), and progression-free survival (PFS) per investigator assessment, overall survival, and safety. Trop-2 expression of archival or baseline tumor specimens was analyzed by immunohistochemistry. At data extraction date, 41 patients were enrolled. Median follow-up was 5.8 months (range, 0.7-19.3); median previous therapies was three (range, 1-6); and 85% of patients received previous chemotherapy and immunotherapy. ORR was 22% (95% CI, 11 to 38); CBR was 32% (95% CI, 18 to 48). Median DOR was 8.8 months (95% CI, 2.8 to not estimable); median PFS was 4.8 months (95% CI, 2.8 to 9.8). Trop-2 exploratory analysis was conducted retrospectively for 39 patients. Tumor Trop-2 protein was highly expressed in EC, showing limited correlation with efficacy. Grade ≥3 treatment-related adverse events (TRAEs) occurred in 73% of patients. Study drug discontinuation due to TRAEs was 5%. Two deaths occurred, deemed unrelated to SG. Findings from TROPiCS-03 showed encouraging efficacy of SG with a manageable toxicity profile in a heavily pretreated population with advanced EC. Safety findings were consistent with the known SG safety profile.

Alliance A022104/NRG-GI010: The Janus Rectal Cancer Trial: a randomized phase II/III trial testing the efficacy of triplet versus doublet chemotherapy regarding clinical complete response and disease-free survival in patients with locally advanced rectal cancer

BackgroundRecent data have demonstrated that in locally advanced rectal cancer (LARC), a total neoadjuvant therapy (TNT) approach improves compliance with chemotherapy and increases rates of tumor response compared to neoadjuvant chemoradiation (CRT) alone. They further indicate that the optimal sequencing of TNT involves consolidation (rather than induction) chemotherapy to optimize complete response rates. Data, largely from retrospective studies, have also shown that patients with clinical complete response (cCR) after TNT may be managed safely with the watch and wait approach (WW) instead of preemptive total mesorectal resection (TME). However, the optimal consolidation chemotherapy regimen to achieve cCR has not been established, and a randomized clinical trial has not robustly evaluated cCR as a primary endpoint. Collaborating with a multidisciplinary oncology team and patient groups, we designed this NCI-sponsored study of chemotherapy intensification to address these issues and to drive up cCR rates, to provide opportunity for organ preservation, improve quality of life for patients and improve survival outcomes.MethodsIn this NCI-sponsored multi-group randomized, seamless phase II/III trial (1:1), up to 760 patients with LARC, T4N0, any T with node positive disease (any T, N +) or T3N0 requiring abdominoperineal resection or coloanal anastomosis and distal margin within 12 cm of anal verge will be enrolled. Stratification factors include tumor stage (T4 vs T1-3), nodal stage (N + vs N0) and distance from anal verge (0–4; 4–8; 8–12 cm). Patients will be randomized to receive neoadjuvant long-course chemoradiation (LCRT) followed by consolidation doublet (mFOLFOX6 or CAPOX) or triplet chemotherapy (mFOLFIRINOX) for 3–4 months. LCRT in both arms involves 4500 cGy in 25 fractions over 5 weeks + 900 cGy boost in 5 fractions with a fluoropyrimidine (capecitabine preferred). Patients will undergo assessment 8–12 (± 4) weeks post-TNT completion. The primary endpoint for the phase II portion will compare cCR between treatment arms. A total number of 312 evaluable patients (156 per arm) will provide statistical power of 90.5% to detect a 17% increase in cCR rate, at a one-sided alpha = 0.048. The primary endpoint for the phase III portion will compare disease-free survival (DFS) between treatment arms. A total of 285 DFS events will provide 85% power to detect an effect size of hazard ratio 0.70 at a one-sided alpha of 0.025, requiring enrollment of 760 patients (380 per arm). Secondary objectives include time-to event outcomes (overall survival, organ preservation time and time to distant metastasis) and adverse event rates. Biospecimens including archival tumor tissue, plasma and buffy coat, and serial rectal MRIs will be collected for exploratory correlative research. This study, activated in late 2022, is open across the NCTN and had accrued 330 patients as of May 2024. Study support: U10CA180821, U10CA180882, U24 CA196171; https://acknowledgments.alliancefound.org.DiscussionBuilding on data from modern day rectal cancer trials and patient input from national advocacy groups, we have designed The Janus Rectal Cancer Trial studying chemotherapy intensification via a consolidation chemotherapy approach with the intent to enhance cCR and DFS rates, increase organ preservation rates, and improve quality of life for patients with rectal cancer.Trial registrationClinicaltrials.gov ID: NCT05610163; Support includes U10CA180868 (NRG) and U10CA180888 (SWOG).

Melanoma progression and prognostic models drawn from single-cell, spatial maps of benign and malignant tumors.

Melanoma clinical outcomes emerge from incompletely understood genetic mechanisms operating within the tumor and its microenvironment. Here, we used single-cell RNA-based spatial molecular imaging (RNA-SMI) in patient-derived archival tumors to reveal clinically relevant markers of malignancy progression and prognosis. We examined spatial gene expression of 203,472 cells inside benign and malignant melanocytic neoplasms, including melanocytic nevi and primary invasive and metastatic melanomas. Algorithmic cell clustering paired with intratumoral comparative two-dimensional analyses visualized synergistic, spatial gene signatures linking cellular proliferation, metabolism, and malignancy, validated by protein expression. Metastatic niches included up-regulation of CDK2 and FABP5, which independently predicted poor clinical outcome in 473 patients with melanoma via Cox regression analysis. More generally, our work demonstrates a framework for applying single-cell RNA-SMI technology toward identifying gene regulatory landscapes pertinent to cancer progression and patient survival.

A Phase II Trial of the WEE1 Inhibitor Adavosertib in SETD2-Altered Advanced Solid Tumor Malignancies (NCI 10170).

WEE1 inhibition with adavosertib monotherapy demonstrated limited clinical activity in patients with SETD2-altered solid tumors despite compelling preclinical data indicating a synthetic lethal effect, which did not translate into robust tumor regression. Loss of the H3K36me3 trimethylation mark caused by SETD2-deficiency was confirmed in the majority of evaluable tumors. A subset of patients derived clinical benefit as manifested by minor tumor regressions and prolonged SD.

NSGO-OV-UMB1/ENGOT-OV30: A phase II study of durvalumab in combination with the anti-CD73 monoclonal antibody Oleclumab in patients with relapsed ovarian cancer

ObjectivesIn patients with epithelial ovarian cancer (EOC), the clinical efficacy of monotherapy with immune checkpoint inhibitors (ICIs) against PD-1/PD-L1 is modest. To enhance response rates to these immunotherapeutic agents and broaden the indications for their use, new approaches involving combinational therapy are needed. The immune regulator CD73 is a potential target, as it promotes tumor escape by producing immunosuppressive extracellular adenosine in the tumor microenvironment. Here, we present the results from the NSGO-OV-UMB1/ENGOT-OV-30 trial evaluating the activity of combining the anti-CD73 antibody oleclumab with the anti-PD-L1 checkpoint inhibitor durvalumab in patients with recurrent EOC. MethodsIn this phase II open-label non-randomized study, patients with CD73-positive relapsed EOC were intravenously administered oleclumab (3000 mg, Q2W) and durvalumab (1500 mg, Q4W). The primary endpoint was disease control rate (DCR) at 16 weeks. The expression of PD-L1 and CD8 was assessed by immunohistochemistry of archival tumors. ResultsThis trial included 25 patients with a median age of 66 years (47–77 years). Twenty-two patients were evaluable for treatment activity analysis. The DCR was 27%, the median progression-free survival was 2.7 months (95% CI: 2.2–4.2) and the median overall survival was 8.4 months (95% CI: 5.0–13.4). Infiltration of CD8+ cells and PD-L1 expression on tumor cells were observed in partially overlapping sets of 74% of the tumor samples. Neither CD8- nor PD-L1-positivity were significantly associated with better DCR. ConclusionsCombined treatment with oleclumab and durvalumab was safe and demonstrated limited anti-tumor activity in patients with recurrent EOC.

Abstract PO-010: Trial in Progress: Phase 1 Study of ARV-393, a PROTAC BCL6 Degrader, in Advanced Non-Hodgkin Lymphoma

Abstract Background: Non-Hodgkin lymphoma (NHL) represents a biologically and clinically diverse group of hematologic malignancies originating from B cells, T cells, and/or natural killer cells, with those of B-cell origin constituting ∼80–85% of all NHL cases. The BCL6 transcription factor is a key oncogenic driver of B-cell lymphomagenesis, and deregulated BCL6 expression is a common feature of diffuse large B-cell lymphoma (DLBCL), the most common type of NHL. BCL6 translocations have been observed in follicular lymphomas, the second most prevalent NHL, with studies suggesting that these translocations may portend a higher risk of transformation into aggressive lymphoma. BCL6 is also a lineage-defining transcription factor of T follicular helper cells, the cell of origin for angioimmunoblastic T-cell lymphoma (AITL). Moreover, BCL6 expression has been identified in biopsies of patients with AITL, and its continued expression was required for tumor growth in a mouse model of AITL, supporting BCL6 as a cancer driver in this type of NHL as well. ARV-393, an orally administered PROteolysis TArgeting Chimera (PROTAC) BCL6 degrader, is a bifunctional small molecule consisting of a BCL6-binding domain attached by a linker to a cereblon E3 ubiquitin ligase–binding domain. ARV-393 induces ubiquitination and subsequent degradation of BCL6 by the proteasome. In preclinical studies, ARV-393 induced rapid and robust degradation (>90%) of BCL6 in NHL cell lines and demonstrated dose-responsive tumor growth inhibition leading to tumor stasis or regression in xenograft models, supporting further investigation in patients with NHL. This multicenter, first-in-human, phase 1 study will evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics, and preliminary antitumor activity of ARV-393 in patients with advanced B-cell NHL or AITL. Methods: Eligible patients (aged ≥18 years) have relapsed/refractory mature B-cell NHL and ≥2 prior systemic therapies, or histologically confirmed AITL that has recurred or progressed following institutional standard-of-care therapy. Patients must also have ≥1 measurable lesion at study entry, Eastern Cooperative Oncology Group performance status of 0 or 1, freshly biopsied or archival tumor tissue available, adequate organ function, no active central nervous system involvement, and no prior allogeneic stem cell transplant or solid organ transplantation. Autologous stem cell transplant must not have occurred ≤100 days and previous CAR T-cell therapy ≤60 days prior to cycle 1 day 1 of ARV-393 treatment. ARV-393 will be administered orally in 28-day cycles with dose escalation according to a Bayesian optimal interval design. The primary objectives are to evaluate the safety and tolerability of ARV-393, determine maximum tolerated dose if necessary, and identify the recommended phase 2 dose(s) and dosing schedule. Secondary objectives are to characterize the pharmacokinetic profile of ARV-393 and evaluate its preliminary anti-tumor activity. Enrollment for this study will open in 2024. Citation Format: Paolo Caimi, Scott Huntington, Sean Landrette, Sheryl M Gough, Vivian Dai, Bryan Jackson, Juan Chavez, Sarah Tannenbaum-Dvir, Matthew Matasar. Trial in Progress: Phase 1 Study of ARV-393, a PROTAC BCL6 Degrader, in Advanced Non-Hodgkin Lymphoma [abstract]. In: Proceedings of the Fourth AACR International Meeting on Advances in Malignant Lymphoma: Maximizing the Basic-Translational Interface for Clinical Application; 2024 Jun 19-22; Philadelphia, PA. Philadelphia (PA): AACR; Blood Cancer Discov 2024;5(3_Suppl):Abstract nr PO-010.

Circulating tumor cells enumeration and characterization in patients with lung cancer treated with immunotherapy.

e15030 Background: Programmed death-ligand 1 (PD-L1) is a predictive biomarker for immunotherapy in the treatment of non-small cell lung cancer (NSCLC). Assessing PD-L1 expression from the tumor specimen can be challenging because of tissue accessibility, heterogeneity, and dynamic changes in PD-L1 expression that may impact the status of PD-L1 during disease evolution and treatment. Hence, assessing PD-L1 status from archival tumor might not reflect its actual state on the tumor and having a real-time assessment of its expression with the use of non-invasive techniques such circulating tumor cells (CTCs) is useful. Methods: We conducted a single centre prospective study to detect CTCs in the blood of patients with stage III-IV NSCLC treated with immunotherapy using the standard CellSearch technology for CTC enumeration and the Epic Sciences technology for CTCs enumeration and assessment of PD-L1 protein expression on CTCs. CTCs were detected at baseline before treatment initiation and after 2 cycles of treatment. Study endpoints included CTCs detection and concordance between the 2 technologies, PD-L1 expression assessment on CTCs with the Epic Sciences technology, and concordance with tissue-based expression. Comparisons were made using Pearson correlation coefficient (PCC) and intraclass correlation coefficient (ICC) for count data and percentage of perfect agreement. Results: Between 2019 and 2022, 48 patients treated with immunotherapy were enrolled in the study. The mean ± standard deviation (SD) age was 66.8 ± 10.3 years, 63% were females, 42% received combination chemotherapy and immunotherapy, and 44% had adenocarcinoma histology. The tissue PD-L1 expression was high (≥50%), intermediate (1-49%), and low (<1%) in 36%, 31% and 33% of patients respectively. The mean ± SD baseline CTCs count per 7.5ml was 1.97 ± 4 with CellSearch and 1.38 ± 2.72 per ml with Epic Sciences. After 2 treatment cycles, 22% and 41% of patients had an increase in their CTCs count with CellSearch and Epic Sciences, respectively and 30% and 29% had a decrease in their CTCs. The PCC and ICC for baseline CTCs detected by CellSearch and Epic Sciences were 0.72 and 0.61, respectively and for CTCs detected after 2 cycles of treatment by the 2 technologies were -0.16 and 0.45 respectively. One patient had PD-L1 expression on their CTCs with the Epic Sciences technology and there was no association between the PD-L1 expression on CTCs and on matched tissue samples. Conclusions: This study showed a moderate to strong correlation between the 2 technologies for baseline CTCs detection and moderate to poor correlation for CTCs detection after 2 cycles of therapy. No association was found between CTCs and tissue PD-L1 expression. Future work needs to further investigate the role of PD-L1 expression on CTCs.

Comprehensive whole genome and transcriptome analysis of patients with advanced solid tumor treated with immune checkpoint inhibitor therapy in the pan-cancer cohorts from the Marathon of Hope Cancer Centres Network Study (MOHCCN).

2645 Background: Immune checkpoint inhibitors (ICI) improve survival in multiple advanced solid tumors but many patients do not benefit. We conducted a comprehensive whole genome transcriptome sequencing (WGTS) analysis to identify predictors of immune sensitivity. Methods: Clinical and molecular data from archival or pre-treatment FFPE tumor tissue were available for analysis from The Marathon of Hope Cancer Centres Network Study (MOHCCN). It includes patients (Pts) with advanced solid tumors and ECOG PS 0 or 1 treated with ICIs targeting PD-1, PD-L1, or CTLA-4 in the INSPIRE (NCT02644369) and OCTANE (NCT02906943) cohorts. Response (R) to ICI was defined as radiological and clinical response without PFS event at 6 months; versus non-response (NR) as radiological or clinical progression within 6 months. Responders without evidence of progression for >12 months were categorized as durable responders (DR). Nucleic acids were sequenced using Illumina NovaSeq 6000 system targeting minimum coverage of 80X and 30X for tumour and normal WGS, respectively and 80M reads for tumour RNA-seq. WGTS data were integrated with clinical data to identify associations with response to ICIs. Also, an analysis of immune cell types was conducted using multiplexed IHC and RNA-Seq deconvolution (CIBERSORT). Results: 59 Pts were included in this analysis: 28 (R) and 31 (NR). The most common tumor types were head and neck (n = 19) and melanoma (n = 7). Median age was 62 years (range 24-81); male 58% and median follow-up was 58 months (range 11-280). The most frequent ICI was pembrolizumab 76%, with 90% of all pts receiving ICI monotherapy and 10% combination. 75% of pts received chemotherapy prior to ICI. Higher tumor mutation burden (TMB) was observed in R vs NR (median 13 vs 5 coding mut/Mb, p=0.001), with the highest TMB in patients with DR (median 14 mut/Mb ). Differential RNA gene expression analysis showed NR had increased expression of several oncogenic pathway signatures, including MYC targets, G2M checkpoint, and E2F targets. Differential abundance analysis of immune cell types did not yield any differences of immune cell populations amongst R versus NR after correction for multiple comparisons. Responders had significant enrichment in mutations in WNT/β-catenin pathway genes in both coding (APC, AMER1, LZTR1, TCF7L2) and promoter regions (CTNNB1). Notably, the 6 Pts with CTNNB1 promoter mutations had significantly increased CTNNB1 gene expression (p = 0.005). Conclusions: ICI responders showed enrichment in coding mutations of several negative regulators of the Wnt/β-catenin pathway and non-coding promoter mutations in CTNNB1 compared with non-responders. Further investigation is ongoing to biologically validate how these mutations in the Wnt/β-catenin pathway may lead to improved response to ICI.

Phase 3 study of disitamab vedotin with pembrolizumab vs chemotherapy in patients with previously untreated locally advanced or metastatic urothelial carcinoma that expresses HER2 (DV-001).

TPS4616 Background: Platinum-based chemotherapy (chemo) has been the standard first-line (1L) therapy for locally advanced or metastatic urothelial carcinoma (la/mUC). Recently, enfortumab vedotin, a nectin-4-directed antibody-drug conjugate (ADC) with a monomethyl auristatin E (MMAE) payload, plus pembrolizumab (pembro) showed improved survival over chemo. Human epidermal growth factor receptor 2 (HER2) expression (immunohistochemistry [IHC] 1+-3+) has been reported in approximately half of all patients (pts) across tumor types, including UC, and is a biomarker that may be associated with poor outcomes. Disitamab vedotin (DV; RC48-ADC) is an investigational ADC comprising a fully humanized HER2-directed monoclonal antibody, disitamab, conjugated to MMAE via a protease-cleavable mc-vc linker. DV elicits antitumor activity through multimodal mechanisms of action, including MMAE-mediated direct cytotoxicity, bystander effect, and immunogenic cell death. DV has shown encouraging activity with a manageable safety profile in pts with la/mUC—as a single agent in a HER2-expressing post-platinum setting (IHC 3+/2+; ORR, 50.5%; median [m]PFS, 5.9 months; mOS, 14.2 months) and in combination with a programmed cell death protein 1 (PD-1) inhibitor in all comers (ORR, 76.0% in treatment-naive pts; 83.3%, 64.3%, and 33.3% in HER2 IHC 3+/2+, IHC 1+, and IHC 0 subgroups, respectively). Improved outcomes observed with an MMAE payload plus PD-1 inhibition across the ADC landscape, along with DV data, provide a robust rationale for this phase 3 trial of DV with pembro in the 1L setting for HER2-expressing la/mUC. Methods: DV-001 (NCT05911295) is an open-label, randomized, multicenter, controlled phase 3 trial evaluating DV with pembro vs chemo in pts with previously untreated HER2-expressing la/mUC. Pts will be randomized 1:1 to Arm A or B. Pts in Arm A will receive DV IV every 2 weeks and pembro IV every 6 weeks. Treatment will continue until disease progression or intolerable toxicity; pembro will be administered for a maximum of 18 6-weekly infusions (approximately 2 years). Pts in Arm B will receive platinum-based chemo with gemcitabine IV on Days 1 and 8 of every 3-week cycle, and either cisplatin or carboplatin on Day 1 of every 3-week cycle for 4-6 cycles. Maintenance therapy with avelumab after completion of chemo may be given to eligible pts where approved and available. Pts must have previously untreated la/mUC, measurable disease per RECIST v1.1, ECOG PS of 0-2 and must be eligible for platinum-based chemo. HER2 expression must be determined using the VENTANA 4B5 HER2 IHC Assay centrally and using the most recent archival or fresh tumor sample. Primary endpoints include PFS per blinded independent central review and OS. Enrollment is ongoing in the US, Canada, and Australia and is planned globally. Clinical trial information: NCT05911295 .

Genomic alterations in DNA damage response (DDR) genes in HR+/HER2- metastatic breast cancer (mBC) and impact on clinical efficacy with sacituzumab govitecan (SG): Biomarker results from TROPICS-02 study.

1075 Background: In the phase 3 TROPiCS-02 study, SG, a Trop-2–directed antibody-drug conjugate coupled to SN-38 as the payload, demonstrated clinically meaningful improvement in survival outcomes over chemotherapy in patients (pts) with pretreated HR+/HER2- mBC. SN-38 leads to double-stranded DNA damage, therefore we hypothesized that in tumors with defective DDR machinery, SG may provoke synthetic lethality. We report on comprehensive genomic analysis of DDR gene variants and the impact on SG clinical efficacy in this patient population. Methods: Pts with HR+/HER2– mBC who received prior taxane, endocrine therapy (ET), CDK4/6 inhibitor, and 2-4 prior lines of chemotherapy were randomized to receive SG (10 mg/kg IV days 1 and 8, every 21 days) or treatment of physician’s choice (TPC) until disease progression or unacceptable toxicity. DDR gene deleterious variants were identified using whole exome sequencing (WES) on archival or screening tumor tissues based on 142 DDR pathway genes annotated in the Kyoto Encyclopedia Genes and Genomes (KEGG) database and Human DNA Repair Gene database; association between these variants and clinical outcomes was evaluated using Cox regression model as Hazard Ratio (HR) with 95% Confidence Intervals (CI). Results: Of 543 patients included in the intent-to-treat (ITT) population, WES data was available for 195 (36%) – clinicopathological features were similar between ITT and WES dataset (median age = 57 vs 58 for SG and 55 vs 55 for TPC; prior lines of chemotherapy >2 lines = 59% vs 57% for SG and 58% vs 55% for TPC). Estrogen Receptor (ER)>10% and prior lines of chemotherapy were comparable between WT and MUT in SG arm and in TPC arm. Overall, 114 (58%) of tumor samples had ≥1 deleterious alteration with BRCA2, PRKDC, ATM being the most common alterations. The primary results are included (Table). Although all patients demonstrated improved efficacy with SG vs TPC, patients with DDR mutant MBC had numerically greater benefit in PFS vs WT (MUT HR= 0.61; WT HR= 0.76) and OS (MUT HR = 0.68; WT HR= 0.82). Conclusions: While SG benefit over TPC was observed in both DDR WT and DDR MUT HR+/HER2– mBC, numerically greater benefit was observed for patients with DDR deficient tumors, suggesting possible synergy between the DDR pathway and SG’s anti-tumor effect. Further study of the synergistic effects of SG in combination with agents targeting DDR pathway are warranted. Clinical trial information: NCT03901339 . [Table: see text]

TTCC-2022-01: Niraparib and dostarlimab in locally-advanced head and neck squamous cell carcinoma treated with (chemo) radiotherapy (RADIAN).

TPS6125 Background: The prognosis of locally-advanced head and neck squamous cell carcinoma (LA-HNSCC) remains poor, with a 60% 5-year overall survival (OS) rate despite curative-intent therapies. Treatment intensification strategies with antiPD-(L)1 agents given concurrently to (chemo)radiotherapy (CRT) have failed to improve survival. New radiosensitizing agents such as PARP inhibitors have shown encouraging results in early studies, and are of special interest in cisplatin-unfit patients (pts) (Moutafi et al. 2021). Beyond radiation sensitization, PARP inhibition is predicted to trigger immune responses via STING pathway activation, and synergize with anti-PD-(L)1 agents (Sen T et al., 2019). We hypothesize that niraparib will enhance antitumor immune responses when combined with dostarlimab before and after definitive CRT and will boost RT response ultimately leading to higher disease-free survival (DFS). Methods: Trial design: RADIAN is an investigator-initiated, multi-center, non-randomized two-cohort phase 1b study of niraparib and dostarlimab in LA-HNSCC pts candidates for CRT (cohort A) or RT alone (cohort B – cisplatin unfit). Dostarlimab 500mg is given intravenously 3 weeks(w) before RT and then q/3w starting w4 post-RT for up to 14 cycles. Niraparib 200 or 300mg is given orally once daily 1w after dostarlimab until start of CRT (cohort A) or continuously until last dose of RT (Cohort B) and then continuously in 3w cycles from w4 post-RT for up to a year (14 cycles). Intensity-modulated RT (70 Grays:2Gray/fraction) and high-dose cisplatin are given as per standard-of-care. Study procedures include collection of baseline archival or fresh tumor sample for molecular profiling, PD-L1 expression and immunophenotyping; serial blood samples for circulating tumor (ct) DNA and clinical/endoscopic photographs of the tumor (baseline, pre-niraparib, pre-RT, 12w post-RT, end-of treatment, and at progression). Imaging and follow-up procedures are conducted as per standard-of-care. Key eligibility criteria: untreated, stage III to IVB laryngeal, hypopharyngeal, HPV-negative oropharyngeal SCC (stage III only if HPV-positive), and stage IVB oral cavity SCC as per TNM 8th edition;adequate organ function; no autoimmune disorders; no immunosuppressive therapy. Study objectives: primary objective is to evaluate 1-year disease free survival. Secondary objectives: safety/tolerability including RT delay/completion; locoregional and distant control, event-free survival, OS and ctDNA dynamics correlation with efficacy endpoints. Sample size: 32 evaluable pts for correlative studies are planned for enrollment (16/cohort). It is expected that experimental treatment will provide an increase of efficacy of 0.64 in terms of HR (1-year DFS of 75.9 % in cohort A and 68.2% in cohort B). Study activation: Nov 11th 2023, with 2 pts enrolled as of Feb 6th 2024. Clinical trial information: NCT05784012 .

Tislelizumab plus concurrent chemoradiotherapy versus concurrent chemoradiotherapy for elderly patients with inoperable locally advanced esophageal squamous cell carcinoma: A multicenter, randomized, parallel-controlled, phase II clinical trial.

TPS4183 Background: There is few high-level prospective randomized studies and international consensus guideline on treatment in elderly patients with inoperable locally advanced esophageal squamous cell carcinoma (LAESCC). Double-agent intravenous chemotherapy concurrent with radiotherapy is the standard of care for LAESCC. However, it’s based on clinical trials that only enrolled patients ≤ 75 years old and infeasible in elderly patients. Oral S-1 plus concurrent radiotherapy for elderly ESCC showed tolerable toxicity and survival benefit compared with radiotherapy alone. While, the 3-year overall survival (OS) rate is limited about 40%. Therefore, it urgently needs find new treatment strategies to further improve the efficacy in elderly ESCC patients. Tislelizumab, the antii-PD-1 antibody, has recently been proved in the first- and second-line standard treatment for advanced ESCC. It shows mild toxicities and might be well-tolerated in the elderly. Here, we conducted the first clinical trial to assess the efficacy and safety of tislelizumab plus concurrent chemotherapy (CCRT) versus CCRT for elderly patients with inoperable LAESCC. Methods: The study is an open label, multicenter, parallel-controlled, investigator-initiated phase II clinical trial in elderly patients with inoperable LAESCC. We plan to enroll 136 elderly patients with LAESCC who will be randomly divided into two groups: tislelizumab combined with CCRT group (tislelizumab + radiotherapy + S-1) and CCRT group (radiotherapy + S-1). Tislelizumab is given intravenously on the first day of CCRT at the dose of 200 mg once every 3 weeks (Q3W). Radiotherapy is delivered at 50.4 Gy/1.8 Gy/28 fraction (5 times per week). S-1 is orally given at the dose of 40-60 mg from day1 to day14 and day 22 to 35. We will evaluate the efficacy and safety during the treatment and follow-up period until disease progression, death or the end of the trial. Considering the median progression free survival (PFS) is 16 months in elder receiving CCRT in history studies, we expect the median PFS would be 28 months at the hazard ratio of 0.57. The final sample size consists in 136 patients by 1:1 randomized in the two groups with 80% power and one-sided alpha and calculating for a 10% dropout rate. The primary endpoint is PFS. Secondary endpoints include OS, objective response rate, duration of objective response and severity of adverse events. Fresh or archival tumor tissues and peripheral blood samples will be used in the exploratory studies. This trial started on October 10, 2023 and has enrolled 19 patients till February 1, 2024. Clinical trial information: NCT06061146 .

Colon adjuvant chemotherapy based on evaluation of residual disease (CIRCULATE-NORTH AMERICA): NRG-GI008.

TPS3641 Background: Currently, there are no biomarkers validated prospectively in randomized studies for resected colon cancer (CC) to determine need for adjuvant chemotherapy (AC). However, circulating tumor DNA (ctDNA) represents a highly specific and sensitive approach (especially with serial monitoring) for identifying minimal/molecular residual disease (MRD) post-surgery in CC patients (pts), and may outperform traditional clinical and pathological features in prognosticating risk for recurrence. CC pts who do not have detectable ctDNA (ctDNA-) are at a much lower risk of recurrence and may be spared the toxicities associated with AC. Furthermore, for CC pts with detectable ctDNA (ctDNA+) who are at a very high risk of recurrence, the optimal AC regimen has not been established. We hypothesize that for pts whose CC has been resected, ctDNA status may be used to risk-stratify for making decisions about AC. Methods: In this prospective phase II/III trial, up to 1,912 pts with resected stage IIB, IIC, and III CC will be enrolled. Based on the post-operative ctDNA status using personalized and tumor-informed assay (Signatera, bespoke assay), those who are ctDNA- (Cohort A) will be randomized to immediate AC with fluoropyrimidine (FP)+oxaliplatin (Ox) for 3-6 mos per established guidelines vserial ctDNA monitoring. Patients who are ctDNA+ post-operatively, or with serial monitoring (Cohort B), will be randomized to FP+Ox v more intensive AC with addition of irinotecan (I) for 6 mos. One cycle of chemotherapy is allowed while awaiting ctDNA testing results for cohort assignment. The primary endpoints for Cohort A are time to ctDNA+ status (phase II) and disease-free survival (DFS) (phase III) in the immediate v delayed AC arms. The primary endpoint for Cohort B is DFS in the FP+Ox v FP+Ox+I arms for both phase II and phase III portions of the trial. Secondary endpoints include prevalence of detectable ctDNA post-operatively, time-to-event outcomes (overall survival and time to recurrence) by ctDNA status, and the assessment of compliance to adjuvant therapy. Biospecimens including archival tumor tissue, as well as post-operative plus serial matched/normal blood samples, will be collected for exploratory correlative research. Active enrollment across the NCTN started in June 2022 with CCTG sites joining in August 2023. Current accrual (as of 02-02-2024) is 240/1,912. NCT05174169. Support: U10-CA-180868, -180822; UG1CA-189867; Natera, Inc. Clinical trial information: NCT05174169 .

Phase I clinical trial of peposertib plus radiation in adults with newly diagnosed MGMT-unmethylated glioblastoma.

2076 Background: DNA-dependent protein kinase (DNA-PK) is a pivotal component of DNA damage repair (DDR) pathways and is an attractive target in glioblastoma because its expression renders tumors less vulnerable to radiotherapy. Peposertib is a small molecule DNA-PK inhibitor that has been pre-clinically shown to potentiate radiotherapy and regress glioblastoma tumors. We conducted a two-stage phase I trial of peposertib plus radiation in patients with newly-diagnosed MGMT-unmethylated glioblastoma (NCT04555577). Methods: In stage 1, patients received concurrent peposertib plus standard-of-care radiotherapy to determine the maximum-tolerated dose (MTD) based on the Bayesian Optimal Interval design (maximum n=24). Stage 2 is a window-of-opportunity expansion cohort and will include 5 surgical patients to evaluate intratumoral drug concentration. Both groups receive 6 cycles of adjuvant temozolomide. Results: Eighteen patients completed the 10-week dose-limiting toxicity (DLT) period; 3@50mg, 3@100mg, 3@200mg, 9@300mg. One DLT (G3 radiation necrosis [RN] at 300mg) was observed. Enrollment of the last three patients into the 300mg dose level began in December 2023 and will complete stage 1. To date, most notable toxicity was transient G3 dermatitis of the scalp (2@200mg, 1@300mg; not a DLT per protocol). Therefore, radiation dose constraints to the skin were incorporated and subsequent patients did not experience this toxicity. After a median follow up of 14.3 months (9.3-18.4), the median OS was 22.9 months [95% CI (16-NR)] and median PFS was 12.7 months [95% CI (9-NR)]. Next-generation sequencing (NGS) was available for 16 archival tumor tissue specimens from patients treated on this trial. Two patients had pathology-proven RN (one within and one outside of the DLT period). Both tumors had baseline mutations in DDR genes (i.e. ATRX, DICER1). Recurrent tissue was available for 4 patients after treatment with peposertib, 2 of which demonstrated gain of DDR gene mutations (2 ATM mutations in one patient and gain of MAD2L2 mutation in another patient). Conclusions: The initial safety data of peposertib plus radiation in patients with newly-diagnosed MGMT unmethylated glioblastoma is favorable. The cases with RN in tumors with DDR mutations, the gain of DDR mutations in recurrent tumors, and the cases of scalp dermatitis suggest peposertib activity may correlate with DDR function, and possibly potentiates the effect of radiation. Stage I is an independent stage of the protocol that will enable MTD determination. Complete safety and survival data and correlations with genomics and spatial transcriptomics for Stage I patients will be presented at the meeting. The study was supported by EMD Serono (CrossRef Funder ID: 10.13039/100004755). Clinical trial information: NCT04555577 .