Exploratory Biomarker Research Articles

Phase I/II study of ipilimumab plus nivolumab (IPI-NIVO) combined with sacituzumab govitecan in patients with metastatic cisplatin-ineligible urothelial carcinoma.

TPS713 Background: Treatment options are suboptimal and limited for cisplatin-ineligible metastatic urothelial carcinoma (mUC) patients. Sacituzumab govitecan (SG) is a Trop-2 directed antibody-drug conjugate (ADC) coupled with SN-38 through a hydrolysable linker. In the phase II TROPHY-U-01 study, SG demonstrated an objective response rate (ORR) of 27% and median overall survival (OS) of 10.5 months in mUC patients who progressed after platinum-based chemotherapy and immune checkpoint inhibitors (ICI), receiving accelerated approval by the US FDA. In CheckMate 032 study, nivolumab 1 mg/kg plus ipilimumab 3 mg/kg (N1+I3) every 3 weeks (Q3W) x 4 cycles followed by nivolumab monotherapy 3mg/kg Q2W showed promising activity post-platinum that led to the ongoing phase III trial in the first-line setting (NCT03036098). Given potential synergism between immunogenic cell death induced by ADC and ICI, we hypothesized that the combination of SG and IPI-NIVO would benefit patients with manageable toxicities. We designed this study to assess the safety and clinical activity of IPI-NIVO with SG as first-line therapy for cisplatin-ineligible mUC patients. Methods: This is an ongoing phase I/II, single arm, multicenter study for cisplatin-ineligible mUC. The Phase I portion enrolled 9 patients using a 3+3 design with safety and RP2D as primary endpoints. In this part, patients received fixed doses of IPI-NIVO (N1+I3) IV Q3Wx 4 cycles combined with SG (DL1 8 mg/kg or DL2 10mg/kg) IV on days 1, 8 Q3W x 4 cycles. This was followed by maintenance nivolumab 360 mg IV Q3W with SG on days 1, 8 Q3W. The RP2D of SG was determined as 8 mg/kg and combination was deemed safe and tolerable. ORR is the primary endpoint in the ongoing phase II portion of the study using Simon 2 stage design (n=34) with a futility interim analysis after 13 patients. The null hypothesis of ORR ≤ 38% will be tested with a desirable ORR of >60% under a statistical power of 80% and a one-sided type I error rate of 5%. Thirteen of the 34 patients have been enrolled and the study has passed the predefined interim analysis for futility. We aim to continue accrual. Exploratory biomarker analyses will be conducted using tumor and blood samples collected during screening and at progression. Clinical trial (NCT04863885). Clinical trial information: NCT04863885 .

Exploratory analyses of homologous recombination repair (HRR) gene subgroups and potential associations with secondary efficacy endpoints in the HRR-deficient population from TALAPRO-2.

178 Background: TALAPRO-2 demonstrated statistically significant improvement in radiographic PFS with 1L talazoparib (TALA) + enzalutamide (ENZA) in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC) with and without HRR gene alterations (HRRm). Tumors were prospectively determined to harbor HRRm. Pts were randomized 1:1 to TALA 0.5 mg (N=200) or placebo (PBO; N=199) + ENZA 160 mg QD. Exploratory biomarker analyses assessed HRR gene subgroups and potential associations with secondary efficacy endpoints in pts with HRRm tumors. Methods: Prospective testing used a 12-gene HRR panel (HRR12) of FoundationOne CDx/FoundationOne Liquid CDx.For single gene groups, only pts bearing alteration(s) in that gene and no other HRR12 genes were analyzed. Gene cluster alteration dominance hierarchy: any BRCA1/2 alteration ( BRCA cluster); any PALB2 ( PALB2 cluster); any CDK12 ( CDK12 cluster); any ATM ( ATM cluster); all other HRR12 genes (each pt counted once). Endpoints: ORR, time to progression or death on first subsequent antineoplastic therapy (PFS2), PSA response ≥50%, time to PSA progression (TTPP), and time to initiation of cytotoxic chemotherapy (TTCC). Results: TALA + ENZA demonstrated differential benefit for BRCA2 single gene group across endpoints: ORR, 78.9% vs 33.3% (odds ratio [OR], 0.13 [95% CI, 0.03–0.63]); PFS2, median not reached (NR) vs 26.1 mo (HR, 0.44 [0.20–0.97]); PSA response >50%, 87.0% vs 58.3%; TTPP, NR vs 9.2 mo (HR, 0.20 [0.10–0.41]); TTCC, NR vs 17.0 mo (HR, 0.27 [0.13–0.57]). Similar broad benefit was seen for BRCA cluster and BRCA1 single gene groups and to a lesser extent PALB2 single gene and cluster groups (allowing for small n in the latter 3 groupings). Broad differential benefit was evident for CDK12 single gene group : ORR 70.0% vs 28.6% (OR 0.17 [0.01–2.03]); PFS2, 36.4 vs 18.8 mo (HR, 0.29 [0.11–0.75]); PSA response ≥50%, 85.7% vs 53.3%; TTPP, 13.8 vs 11.1 mo (HR 0.61 [0.29–1.26]); the exception was TTCC, NR vs NR (HR 1.32 [0.43–4.06]). Similar benefit was seen for CDK12 cluster. For ATM single gene group, differential numerical benefit was seen for ORR, 81.8% vs 20.0% (OR 0.06 [0.00–1.17]); TTPP, 26.8 vs 15.9 mo (HR, 0.61 [0.25–1.47]); TTCC, NR vs NR (HR 0.60 [0.18–1.96]); no differential benefit was seen in other endpoints (similar for ATM cluster). The CHEK2 single gene group showed numerically differential benefit for PSA endpoints and TTCC. The other HRR12 gene cluster typically showed comparable efficacy between arms with potential exception of TTPP, 28.6 vs 14.0 mo (HR 0.65 [0.33–1.31]), and TTCC, NR vs NR (HR 0.65 [0.26–1.62]). Conclusions: Broad differential efficacy benefit was evident for TALA + ENZA vs PBO + ENZA across multiple molecular subgroups and was most pronounced for the BRCA1- PALB2- BRCA2 axis and CDK12. Additional analyses are warranted. Clinical trial information: NCT03395197 .

Predictive value of dynamic changes in ctDNA and baseline biomarkers with neoadjuvant atezolizumab in operable urothelial carcinoma in the ABACUS trial.

534 Background: Circulating tumour DNA (ctDNA) is being explored in the neoadjuvant setting in multiple prospective trials. Dynamic changes may be a surrogate marker of pathological complete response. ABACUS was a multi-centre, single-arm phase II trial investigating two cycles of atezolizumab before cystectomy in patients with muscle-invasive urothelial cancer who were ineligible for or refused neoadjuvant cisplatin-based chemotherapy (NCT02662309). Results of primary and secondary endpoints have been previously published. Here we perform exploratory biomarker analysis using different definitions of ctDNA response and assess correlation with tissue response at time of cystectomy in the ABACUS trial. We also assess how these definitions of response correlate with baseline biomarker expression. Methods: Patients with baseline PDL-1, CD8, TMB and sequential ctDNA measurements (baseline and at cystectomy) were included. ctDNA analysis was performed using the Signatera assay, PD-L1 positivity was defined as ≥5% of immune cell staining, TMB was assessed using the FoundationOne CDx assay and CD8 measurement was performed via immunohistochemistry analyses. Two definitions of ctDNA response were used—ctDNA clearance and a 50% reduction (or greater) in ctDNA variant allele frequency (VAF). Results were correlated with pathological complete response (pCR) rate at time of cystectomy and relapse-free survival. Results: The 2-yr DFS and OS rates in ABACUS were 68% and 77%, respectively (N=95). 40 patients had sequential DNA analysis. 43% (17/40) had pathological complete response and 20% (8/40) experienced relapse. 63% (25/40) patients were ctDNA+ at baseline, with 40% (10/25) having ctDNA response of 50% VAF reduction and 8% (3/40) achieving ctDNA clearance. 30% (3/10) of patients who had VAF reduction experienced relapse and 40% (4/10) achieved pCR. All patients with ctDNA clearance achieved pCR none relapsed. There was no association between VAF reduction of 50% and tissue response (pCR) (p=0.24). Additional analysis showed no association between a ctDNA reduction of 75% (rather than 50%) and pCR (p=0.24). Baseline PDL-1, TMB and not predictive of pathological complete response (p=0.18, p=0.77, p=0.10, respectively) or ctDNA response (p=0.54, p=0.77, p=0.74) to neoadjuvant atezolizumab. There was no difference in relapse rates between ctDNA/PD-L1+ve vs ctDNA+ve/PD-L1-ve patients (16% vs 16%, respectively). Conclusions: ctDNA clearance is rare but appears more accurate than 50% reduction in VAF to predict response/relapse. This is relevant for ongoing neoadjuvant trials planning to use this as an endpoint. Combining immune tissue based biomarkers with ctDNA does not appear to improve biomarker accuracy.

Abstract IA26: Exploring breast cancer vulnerabilities through apoptotic pathways

Abstract Combined CDK4/6 inhibitor and endocrine therapy has rapidly become standard therapy for patients with early line relapsed estrogen receptor (ER)-positive, HER2-negative breast cancer. Although this combination has been shown to significantly improve progression free and overall survival, relapse is virtually inevitable. This may in part be due to the profound cytostatic effect of CDK4/6 inhibitors on tumors, which is associated with reduced apoptotic cell death. It seems likely that growth arrested and/or senescent tumor cells acquire resistance to therapy, leading to relapse. BH3 mimetics are an emerging class of drug that target pro-survival proteins such as BCL2, BCL-xL and MCL1. Venetoclax, a BH3 mimetic that has potent and specific activity against BCL2, has shown considerable promise in hematopoietic tumors such as CLL, but has yet to be fully explored in solid tumors. We have previously demonstrated safety and efficacy of combining tamoxifen with venetoclax for patients with metastatic ER-positive BCL2-positive disease using pre-clinical PDX models and a dose-finding phase 1 study [mBEP study, ISRCTN98335443], where most patients were CDK4/6 inhibitor therapy-naïve. In the post-CDK4/6 inhibitor setting, however, venetoclax did not improve clinical benefit rate or progression free survival when added to fulvestrant in the phase 2 study VERONICA [NCT03584009]. In that study a minority of tumours exhibited strong BCL2 expression and exploratory biomarker analysis revealed a trend towards improved progression free survival for patients with tumors exhibiting high BCL2 expression (IHC 3+), a BCL2:BCL-xL Histoscore ratio ≥1, or with PIK3CA wild-type status. Using pre-clinical models including patient derived xenografts of ER-positive breast cancer, we have shown that the addition of venetoclax to dual therapy comprising fulvestrant and the CDK4/6 inhibitor palbociclib elicits a superior and more durable tumor response, accompanied by increased apoptosis. These findings have formed the basis of a phase 1 clinical trial of palbociclib, letrozole and venetoclax [PALVEN, NCT03900884] in patients with early line relapsed ER and BCL2-positive metastatic breast cancer. In parallel, pre-clinical studies are underway to determine the effect of dual targeting BCL-xL and MCL1, as well as dual targeting of AKT and with a BH3 mimetic in CDK4/6 inhibitor refractory breast cancer cells. Citation Format: James R Whittle, François Vaillant, Elliot Surgenor, Luuk Heitink, Christine Muttiah, Jane E Visvader, Geoffrey J Lindeman. Exploring breast cancer vulnerabilities through apoptotic pathways [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Breast Cancer Research; 2023 Oct 19-22; San Diego, California. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_1):Abstract nr IA26.

Efficacy and safety of the combination of cisplatin plus nab-paclitaxel and nivolumab with radiotherapy after maximal tumor resection in non-metastatic muscle invasive bladder cancer (CNN-BC trial).

TPS723 Background: The therapeutic gold standard for muscle invasive bladder cancer (MIBC) is radical cystectomy (RC) preceded by neoadjuvant chemotherapy when appropriate. However, RC is a major surgery procedure with 13% rate of severe complication and a perioperative mortality rate of about 1.5 - 5 %. Trimodal therapy (TMT) is a “bladder sparing” option alternative to RC. TMT consists of complete transurethral bladder tumor resection (TURBT) followed by a combination of systemic chemotherapy and locoregional radiotherapy (RT), with the option of “salvage” cystectomy in case of local treatment failure. Immunotherapy with anti-PD1/PD-L1 monoclonal antibody significantly improves survival of metastatic BC patients, and it seems to potentiate the activity of RT without increased toxicity. Therefore, we investigate the role of a multimodal TMT strategy to increase the disease-free survival (DFS) and avoid or delay RC in non-metastatic MIBC pts. Methods: CNN-BC trial (NCT05203913) is a phase 2, open-label, mono-institutional study evaluating the activity and safety of TMT with cisplatin, nab-paclitaxel and nivolumab as systemic therapy in non-metastatic MIBC pts. Eligible pts should have undergone complete TURBT with diagnosis of T2-T3 N0M0 urothelial carcinoma, and no evidence of lymph nodes or metastatic disease at FDG-PET within 6 weeks from the start of treatments. TMT consists of nivolumab (480 mg IV every 4 weeks for a total of 13 doses), weekly nab-paclitaxel (60mg/m2) plus cisplatin (20mg/m2) administered concurrently with RT (60Gy in 25 fractions over 5 weeks on original bladder tumor, plus a concomitant boost of 50Gy in 25 fractions on whole bladder and pelvic nodes). The primary endpoint is the 1-year DFS rate, defined as the rate of survival free of recurrence in pelvic nodes or bladder, or appearance of distant metastases. Secondary endpoints include: the rate of pts who require salvage cystectomy, the rate of locoregional complete response (CR) and of locoregional DFS, median DFS, safety, and quality of life. Exploratory biomarkers analysis will be performed. The trial is actively recruiting. Clinical trial information: NCT05203913 .

UTILITY OF PR3-ANCA IN PATIENTS WITH INFLAMMATORY BOWEL DISEASE: A SYSTEMATIC REVIEW AND META-ANALYSIS

Abstract BACKGROUND/PURPOSE Anti-neutrophil cytoplasmic antibodies (ANCA) directed to proteinase 3 (PR3) represent a highly established marker for patients with ANCA-associated vasculitis (AAV). PR3-ANCA have also demonstrated utility in the management of inflammatory bowel disease (IBD) with certain immunoassays. More specifically, PR3-ANCA discriminated patients with ulcerative colitis (UC) from Crohn`s disease (CrD) patients and were associated with disease severity and activity. Lastly, evidence is mounting that PR3-ANCA helps to stratify patients according to treatment response. Here, we aimed to summarize the current data on the diagnostic utility of PR3-ANCA in IBD. METHODS A structured systematic literature review including three electronic databases (Pubmed, Scopes, and Web Of Science) was conducted on June 6th 2023 to identify studies assessing the diagnostic accuracy of the QUANTA Flash PR3 assay (RUO for IBD) in UC vs. CrD patients. Electronic searches were supplemented by hand searching. A hierarchical, bivariate, mixed-effect meta-analysis was conducted using metandi function in STATA MP v17.0, as per the Cochrane collaboration recommendations for a review of diagnostic test accuracy studies. Study quality was assessed using QUADAS-2 tool which considers the risk of bias and applicability. RESULTS Out of 111 citations retrieved for titles and abstracts screen, a total of 6 studies met the inclusion criteria and reported QUANTA Flash PR3 diagnostic accuracy in UC vs. CrD. Diagnostic test accuracy of individual studies is available in Table 1. The six studies included 667 UC patients and 682 individuals with CrD. Of these, 2 articles (Horn et al. and Laass et al) were case-control studies in children. Sensitivity point estimate for UC was 34.9% [95% confidence interval (CI): 26.2-44.6%]. Specificity point estimate for CrD was 95.9% (95% CI: 92.0-98.0%). This results in a Diagnostic Odds Ratio (DOR) of 12.6 (95% CI: 5.7-27.9%), a positive likelihood ratio of 8.5 (95% CI: 4.2-17.5), and a negative likelihood ratio of 0.68 (95% CI: 0.59-0.78) (Table 2). The risk of bias was low in the index test and reference standard domains. Four studies (67%) showed an unclear risk of bias in the patient selection and flow and timing domains. All studies had low concerns of applicability in all the domains. CONCLUSION In this meta-analysis QUANTA Flash PR3 assay has demonstrated to be able to discriminate between UC from CrD with a sensitivity of 34.9% and a specificity of 95.9%. Due to the limited number of studies published, clinical trials should consider the inclusion of PR3-ANCA as an exploratory biomarker for patient stratification. Table 1 Summary of diagnostic test accuracy of individual studies. Table 2 Meta-analysis of diagnostic test accuracy of QUANTA Flash PR3.

Analysis of tumor biomarkers in patients (pts) with advanced hepatocellular carcinoma (HCC) from a phase 1b study of E7386, a CREB-binding protein/β-catenin interaction inhibitor, in combination with lenvatinib.

535 Background: E7386, a novel oral anticancer agent, inhibits β-catenin binding to its transcriptional co-activator CREB-binding protein, thus modulating Wnt/β-catenin signaling. Lenvatinib is a multikinase inhibitor that targets VEGFR 1–3, FGFR 1–4, PDGFRα, RET, and KIT. We previously reported the safety/tolerability, pharmacokinetics, biomarkers, and preliminary efficacy of E7386 plus lenvatinib in 25 pts with HCC in the dose escalation part of a phase 1b study1 (NCT04008797). Here, we present the results of exploratory tumor biomarker analyses from this study. Methods: Pts with HCC were treated with E7386 10–80 mg QD and 60–120 mg BID plus lenvatinib (bodyweight < 60 kg: 8 mg QD; ≥ 60 kg: 12 mg QD). Archival or fresh tumor samples were collected at baseline and post-treatment; tumor tissue was assessed for genetic alteration, immunohistochemistry (IHC), and gene expression. Gene signature scores of interest were calculated using obtained gene expression data. The preliminary association between biomarker status and efficacy was investigated. Results: Of the 25 pts enrolled, 22 had baseline tumor samples available for the gene mutation analysis. TERT (6 pts: 27%), CTNNB1 (5 pts: 23%), and TP53 (4 pts: 18%) mutations were detected. CTNNB1 mutation was confirmed in 3 of 7 responders and 2 of 13 non-responders. Nuclear β-catenin expression was confirmed by IHC analysis in 5 of 16 pts; it was expressed in 3 of 5 pts with CTNNB1 MUT and 2 of 11 pts with CTNNB1 WT. Pts with expression of nuclear β-catenin had 2 partial responses (PRs) among 5 pts; those without β-catenin expression had 2 PRs among 11 pts. Additionally, IHC analysis of tumor microvessel density (MVD; number of CD31+ vessels) at baseline suggested that greater maximum tumor shrinkage (MTS) tended to be observed in the MVD-high population compared to the MVD-low population. 7 Pts had evaluable baseline and post-baseline tumor samples and were included in the gene signature analysis. Despite the small sample size, preliminary results indicated that MTS may be associated with a decrease in Wnt signaling and angiogenesis gene signature scores (spearman r [r]=0.61 for both) and attenuation of hypoxic induction and glycolysis gene signature scores (r=0.79 and 0.68, respectively). Conclusions: These exploratory tumor biomarker analyses suggest that E7386 in combination with lenvatinib may affect the tumor microenvironment in HCC pts through effects on Wnt signaling, angiogenesis, hypoxic response, and glycolysis pathways. This concept is the basis for treatment with this combination. However, given the small sample size, further investigation is needed to confirm these effects on the tumor microenvironment. Enrollment of pts with HCC to the expansion part of Study 102 is ongoing. 1. Ikeda et al. ASCO 2023. Clinical trial information: NCT04008797 .

Neoadjuvant anti-programmed death 1 (PD-1) therapy in patients (pts) with resectable mismatch repair–deficient (dMMR) locally advanced rectal cancer (LARC): EPOC2201.

TPS226 Background: Neoadjuvant radiotherapy and chemotherapy followed by surgical resection is a standard treatment for LARC. As anti-PD-1 therapy for patients with dMMR colorectal cancer is responsive in the context of metastatic disease, several clinical trials which evaluate the efficacies of anti-PD-1 therapy in patients with dMMR LARC are on-going and suggested the outstanding responses (Cercek A. et al., N Engl J Med 2022). Methods: We initiated the EPOC 2201 VOLTAGE-2 study, which is an ongoing, non-randomized, single-arm phase II trial. The major eligibility criteria were as follows: treatment-naïve with rectal cancer located 12 cm from the anal verge; confirmed dMMR; clinical stage II/III in primary cohort (N=35) and stage I in exploratory cohort (N=20); age ≥ 18; Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1; and presence of sufficient organ function. The study treatments include 12 cycles of nivolumab (NIVO) monotherapy (240 mg every 2 weeks) followed by assessment using Memorial Sloan Kettering (MSKCC) Regression Schema (Smith J.J. et al., BMC Cancer 2015). If clinical complete response (cCR) or near complete response (nCR) are observed, non-operative management with additional 12 cycles of NIVO will be performed. If incomplete response (IR) is observed, standard chemoradiotherapy with 50.4Gy of radiation plus capecitabine followed by surgery will be performed. The primary endpoint is the 2-year cCR rate in primary cohort. Various survival endpoints including progression-free survival (PFS) and overall survival (OS) are assessed as secondary endpoints. Safety analyses are performed using the Common Terminology Criteria for Adverse Events (CTCAE) ver. 5.0, and the Clavien‒Dindo classification (ver. 2.0) is added for postoperative complications. Assuming null and alternative hypotheses, cCR rates of 23% and 45%, the planned sample size for primary cohort was set at 35, with a one-sided alpha of 5% and power of 80%. An exploratory biomarker study was also conducted using serially collected tumor and blood samples. Whole genome-based minimal residual disease (MRD) assay and whole exome/whole transcriptome-based tumor and immune microenvironment analyses are performed. As of August 2023, patient’s enrollment is ongoing. Clinical trial information: jRCT2031220484 .

Nivolumab (NIVO) plus (+) chemotherapy (chemo) or ipilimumab (IPI) vs chemo as 1L treatment for advanced esophageal squamous cell carcinoma (ESCC): First comprehensive biomarker analyses from CheckMate 648.

252 Background: NIVO + chemo and NIVO + IPI demonstrated superior overall survival (OS) vs chemo in previously untreated patients with advanced ESCC in CheckMate 648 (NCT03143153), resulting in approvals in many countries. We present first comprehensive exploratory biomarker analysis results from this trial. Methods: Whole exome sequencing (WES) of baseline tumor tissue and matching blood was performed to assess tumor mutational burden (TMB) and select gene alterations. TMB-high tumors were defined as ≥ 199 mutations/exome. RNA sequencing of baseline tumor tissue was used to assess gene expression signatures (GES). GES subgroups were defined by signature score tertiles. Results: In total, 60% (191/321) of patients receiving NIVO + chemo were both WES- and GES-evaluable; 62% (200/325) and 58% (188/325) of patients receiving NIVO + IPI and 59% (190/324) and 59% (192/324) receiving chemo were WES- and GES-evaluable, respectively. In the NIVO + chemo arm, patients with TMB-high tumors had numerically longer median OS (mOS) compared with TMB-low tumors, whereas mOS was similar between TMB subgroups treated with NIVO + IPI, although the number of patients with TMB-high tumors was small (Table). Higher inflammation and lower β-catenin GES scores were associated with improved OS benefit of NIVO + chemo or IPI vs chemo (Table). Lower fibroblast GES scores were associated with improved OS benefit of NIVO + IPI vs chemo (Table). Additional biomarker analyses, including select gene alterations and GES in tumor cell PD-L1 subgroups, will be presented. Conclusions: These results further support the clinical efficacy of NIVO + chemo and NIVO + IPI in 1L ESCC and suggest enhanced OS benefit in multiple biomarker subgroups. The clinical utility of these biomarkers should be validated in future trials. Clinical trial information: NCT03143153 . [Table: see text]

Alliance A022101: A pragmatic randomized phase III trial evaluating total ablative therapy for patients with limited metastatic colorectal cancer—Evaluating radiation, ablation, and surgery (ERASur).

TPS236 Background: For patients with oligometastatic colorectal cancer (CRC), aggressive local therapy of isolated metastases, particularly in the liver, has been associated with long-term progression-free survival and overall survival (OS) primarily based on retrospective evidence. However, in patients with limited metastatic CRC that is deemed inoperable or those with additional disease outside of the liver or lungs, the role of local ablative therapies, including microwave ablation (MWA) and stereotactic body radiation therapy (SBRT), to render patients disease free is less clear. Further, despite the long history of treating oligometastatic CRC with local therapy, which is provider biased and not evidence based, questions remain regarding the benefit of extending the paradigm of metastatic directed therapy to patients with more extensive disease. This trial seeks to use a pragmatic multimodality approach that mirrors the current clinical dilemma. This study is designed to evaluate the safety and efficacy of adding total ablative therapy (TAT) of all sites of disease to standard of care systemic treatment in those with limited metastatic CRC. Methods: A022101 is a National Clinical Trials Network randomized phase III study planned to enroll 364 patients with newly diagnosed metastatic CRC (BRAF wild-type, microsatellite stable) with ≤4 sites of metastatic disease on baseline imaging. Liver-only metastatic disease is not permitted, and lesions must be amenable to any combination of surgical resection, MWA, and/or SBRT with SBRT required for at least one lesion. Patients receive first-line systemic therapy for 4-6 months and are then randomized 1:1, stratified by number of metastatic organ sites (1-2 vs. 3-4), timing of metastatic disease diagnosis (de novo vs. secondary), and presence of metastatic disease outside the liver and lungs in at least one site. Patients in Arm 1 will receive TAT which consists of treatment of all metastatic sites with SBRT ± MWA ± surgical resection followed by standard of care systemic therapy. Patients in Arm 2 will continue with standard of care systemic therapy alone. The primary endpoint is OS. Secondary endpoints include event-free survival, treatment-related toxicities, and local recurrence with exploratory biomarker analyses. The study needs 346 evaluable patients combined in the 2 arms to demonstrate an improvement in OS with a hazard ratio of 0.7 to provide 80% power with a one-sided alpha of 5%. The trial utilizes a group sequential design with two interim analyses (25% and 50% of events) for futility. The trial activated in January 2023 and recruitment is ongoing. Support: U10CA180821, U10CA180882; https://acknowledgments.alliancefound.org. U10CA180820 (ECOG-ACRIN); U10CA180868 (NRG); U10CA180888 (SWOG). Clinical trial information: NCT05673148 .

Comprehensive molecular characteristics of clinical responses to PD-1 inhibitors plus anti-angiogenic agents (PA) in metastatic HER2-negative gastric adenocarcinoma.

279 Background: Anti-angiogensis agents were reported to enhance the efficacy of PD-1 inhibitor by inhibiting the infiltration of suppressive immune cell populations. Clinical studies indicated the synergistic anti-tumor effect of the combination of PD-1 inhibitors and anti-angiogenesis agents (PA). We aim to assess the efficacy of PA versus chemo-PA regiment in mGC, as well as the potential predictive biomarkers. Methods: A total of 55 GC tumors were analyzed using the next-generation sequencing (NGS), immunohistochemistry (IHC), and the tumor immune microenvironment (TIME) by multiplex immunofluorescence (mIHC). Clinical outcomes [Disease Control Rate (DCR), Progression-free survival (PFS) and overall survival (OS)] were compared between patients receiving PA treatment (n=32) and chemo-PA (n=23) treatment. Exploratory biomarker analyses were conducted for the prediction for the efficacy of PA/chemo-PA treatment. Results: Patients receiving PA regiment had comparable DCR (69% vs 50%, P =0.25) and PFS (median PFS: 6.53 vs 4.73 months, HR=0.70, 95%CI: 0.27-1.78, P =0.52), compared with those treated with combination of chemo-PA regiment as second or later-line treatment in mGC. Patients with HMCN1 wild-type showed significant improvements in DCR (77% vs 0%, P =0.023) and PFS (median PFS: 6.53 vs 1.17 months, P =0.0017), versus those with HMCN1 mutations in PA treatment cohort. HMCN1 mutations are associated with lower infiltration of endothelial cells and lower score of VEGF ligand-receptor interaction, according to the EPIC and pathway enrichment analysis ( P < 0.05). In addition, analysis of TIME by mIHC revealed that the fraction of CD68+ tumor-associated macrophages in the tumor center was higher in responders than non-responders before treatment (median: 17.59% vs 2.45%, P=0.016). Conclusions: PA regiment and chemo-PA regiment had similar efficacy in second or later line treatment of mGC. HMCN1 mutations maybe a predictive marker for PA regiment in HER2-negative mGC, which should be further validated in a large cohort.

Real-world analysis of patients with advanced gastrointestinal (GI) cancers harboring inactivating TSC1 and TSC2 alterations using the Foundation Medicine genomic database.

558 Background: Genomic profiling of GI tumors can identify potentially actionable genetic alterations, ultimately leading to better outcomes in patients who currently have few treatment options. In exploratory biomarker analyses of patients with perivascular epithelioid cell tumors treated with the mTOR inhibitor nab-sirolimus (AMPECT, NCT02494570), those with inactivating alterations in the tumor suppressor genes TSC1 or TSC2 (critical negative regulators of mTOR activity) had confirmed responses (8/9 patients with inactivating TSC2 alterations and 1/5 patients with inactivating TSC1 alterations). PRECISION 1, a currently enrolling tumor-agnostic study, will evaluate nab-sirolimus in patients with TSC1 or TSC2 alterations. To enumerate the frequency of these alterations in GI cancers, we analyzed data from a real-world genomic database. Methods: Next-generation sequencing (NGS) data from Foundation Medicine’s genomic database of patients with advanced cancer were analyzed using the FoundationInsights web-based platform to identify patients with GI cancers who had inactivating TSC1 or TSC2 alterations (short variants [base substitutions, insertions and deletions], rearrangements, and copy number deletions). Tumor mutational burden (TMB), microsatellite instability status and other mutations were also characterized in this group of patients. Results: As of 29 March 2022, tumor tissue NGS data were available for 5816 patients with GI cancers bearing alterations in TSC1 or TSC2. Of these, 1642 patients had at least one inactivating alteration. The GI tumor types that most frequently expressed inactivating alterations in TSC1 or TSC2 were hepatocellular carcinoma (alterations in 6.5%); colorectal adenocarcinoma (1.7%); gastrointestinal stromal tumors (1.7%); and cholangiocarcinoma (1.6%). Of all 1642 patients, 688 were female, and most (74%) were 51–80 years of age when the sample was obtained. Of patients with inactivating TSC1 and TSC2 alterations, 37.6% were in TSC1 and 62.9% were in TSC2 and included short variants (31.3% and 48.4%), rearrangements (2.7% and 6.6%), and copy number deletions (3.5% and 7.4%), respectively. TMB was low (<6 mutations/megabase) in 58% of patients, and most patients had microsatellite stable (MSS; 71.3%) tumors. Other commonly mutated genes in this cohort were TP53 (62.7%), APC (38.5%) and KRAS (30.4%). Conclusions: TSC1 and/or TSC2 alterations were commonly observed in GI cancers. These cancers were frequently microsatellite stable and of low TMB suggesting that these are actionable alterations that may be candidates for targeted therapy. This hypothesis is being tested in the PRECISION 1 (NCT05103358) trial which is open for enrollment or just-in-time clinical trial sites and available to patients with GI cancers harboring TSC1 or TSC2 alterations.

Efficacy and Safety of the Natural Killer T Cell-Stimulatory Glycolipid OCH-NCNP1 for Patients With Relapsing Multiple Sclerosis: Protocol for a Randomized Placebo-Controlled Clinical Trial.

Multiple sclerosis (MS) is an autoimmune inflammatory disease of the central nervous system that causes myelin sheath damage and axonal degeneration. The glycolipid (2S, 3S, 4R)-1-O-(α-d-galactosyl)-2-tetracosanoylamino-1,3,4-nonaetriol (OCH-NCNP1 or OCH) exerts an immunoregulatory action that suppresses T helper (Th)1 cell-mediated immune responses through natural killer T cell activation, selective interleukin-4 production, and Th2 bias induction in human CD4-positive natural killer T cells. This trial aims to investigate the efficacy and safety of the immunomodulator OCH in patients with relapsing MS through 24-week repeated administration. This protocol describes a double-blind, multicenter, placebo-controlled, randomized phase II clinical trial that was initiated in September 2019. The participants were randomly assigned to either a placebo control group or an OCH-NCNP1 group and the investigational drug (3.0 mg) was orally administered once weekly for the 24-week duration. Major inclusion criteria are as follows: patients had been diagnosed with relapsing MS (relapsing-remitting and/or secondary progressive MS) based on the revised McDonald criteria or were diagnosed with MS by an attending physician as noted in their medical records; patients with at least two medically confirmed clinical exacerbations within 24 months prior to consent or one exacerbation within 12 months prior to consent; patients with at least one lesion suspected to be MS on screening magnetic resonance imaging (MRI); and patients with 7 points or less in the Expanded Disability Status Scale during screening. Major exclusion criteria are as follows: diagnosis of neuromyelitis optica and one of optic neuritis, acute myelitis, and satisfying at least two of the following three items: (1) spinal cord MRI lesion extending across at least three vertebral bodies, (2) no brain MRI lesions during onset (at least four cerebral white matter lesions or three lesions, one of which is around the lateral ventricle), and (3) neuromyelitis optica-immunoglobulin G or antiaquaporin-4 antibody-positive. Outcome measures include the primary outcome of MRI changes (the percentage of subjects with new or newly expanded lesions at 24 weeks on T2-weighted MRI) and the secondary outcomes annual relapse rate (number of recurrences per year), relapse-free period (time to recurrence), sustained reduction in disability (SRD) occurrence rate, period until SRD (time to SRD occurrence), no evidence of disease activity, and exploratory biomarkers from phase I trials (such as gene expression, cell frequency, and intestinal and oral microbiome). We plan to enroll 30 patients in the full analysis set. Enrollment was closed in June 2021 and the study analysis was completed in March 2023. This randomized controlled trial will determine whether OCH-NCNP1 is effective and safe in patients with MS as well as provide evidence for the potential of OCH-NCNP1 as a therapeutic agent for MS. ClinicalTrials.gov NCT04211740; https://clinicaltrials.gov/study/NCT04211740. DERR1-10.2196/46709.

The atorvastatin metabolite pattern in muscle tissue and blood plasma is associated with statin muscle side effects in patients with coronary heart disease; An exploratory case-control study

Background and aimsStatin-associated muscle symptoms (SAMS) is a prevalent cause of statin discontinuation. It is challenging and time-consuming for clinicians to assess whether symptoms are caused by the statin or not, and diagnostic biomarkers are requested. Atorvastatin metabolites have been associated with SAMS. We aimed to compare atorvastatin pharmacokinetics between coronary heart disease (CHD) patients with and without clinically statin intolerance and statin-dependent histopathological alterations in muscle tissue. Secondarily we aimed to assess genetic variants relevant for the observed pharmacokinetic variables. MethodsTwenty-eight patients with CHD and subjective SAMS were included in the exploratory MUSE biomarker study in 2020. Participants received atorvastatin 40 mg/day for seven weeks followed by no statins for eight weeks. Muscle biopsies and blood were collected at the end of each period. Four patients were categorized as clinically intolerant to ≥3 statins prior to study start whereas four patients had signs of muscle cell damage during treatment. ResultsWe found significantly lower levels of atorvastatin acids, and higher lactone/acid ratios in the statin intolerant, both in muscle and plasma. With optimal cut-off, the combination of 2-OH-atorvastatin acid and the 2-OH-atorvastatin lactone/acid ratio provided sensitivity, specificity, and predictive values of 100 %. Patients with variants in UGT1A1 and UGT1A3 had higher lactone metabolite levels than those with wild type, both in muscle and plasma. ConclusionAtorvastatin metabolites appear promising as biomarkers for the identification of clinical statin intolerance in patients with self-perceived SAMS, but the findings have to be confirmed in larger studies.

Durable response after tisagenlecleucel in adults with relapsed/refractory follicular lymphoma: ELARA trial update

AbstractTisagenlecleucel is approved for adults with relapsed/refractory (r/r) follicular lymphoma (FL) in the third- or later-line setting. The primary analysis (median follow-up, 17 months) of the phase 2 ELARA trial reported high response rates and excellent safety profile in patients with extensively pretreated r/r FL. Here, we report longer-term efficacy, safety, pharmacokinetic, and exploratory biomarker analyses after median follow-up of 29 months (interquartile range, 22.2-37.7). As of 29 March 2022, 97 patients with r/r FL (grades 1-3A) received tisagenlecleucel infusion (0.6 × 108-6 × 108 chimeric antigen receptor–positive viable T cells). Bridging chemotherapy was allowed. Baseline clinical factors, tumor microenvironment, blood soluble factors, and circulating blood cells were correlated with clinical response. Cellular kinetics were assessed by quantitative polymerase chain reaction. Median progression-free survival (PFS), duration of response (DOR), and overall survival (OS) were not reached. Estimated 24-month PFS, DOR, and OS rates in all patients were 57.4% (95% confidence interval [CI], 46.2-67), 66.4% (95% CI, 54.3-76), and 87.7% (95% CI, 78.3-93.2), respectively. Complete response rate and overall response rate were 68.1% (95% CI, 57.7-77.3) and 86.2% (95% CI, 77.5-92.4), respectively. No new safety signals or treatment-related deaths were reported. Low levels of tumor-infiltrating LAG3+CD3+ exhausted T cells and higher baseline levels of naïve CD8+ T cells were associated with improved outcomes. Tisagenlecleucel continued to demonstrate highly durable efficacy and a favorable safety profile in this extended follow-up of 29 months in patients with r/r FL enrolled in ELARA. This trial was registered at www.clinicaltrials.gov as #NCT03568461.

Vitreous Biomarkers for Proliferative Vitreoretinopathy Prognostication in Patients Undergoing Primary Retinal Detachment Repair.

To compare baseline levels of exploratory biomarkers in the vitreous fluid of patients with primary retinal detachment who subsequently develop proliferative vitreoretinopathy (PVR) versus those who do not. In this exploratory case-control study, we evaluated the baseline protein biomarker levels from a biobank containing the vitreous fluid of patients who had undergone primary pars plana vitrectomy (PPV) for rhegmatogenous retinal detachment. Undiluted samples were collected at the time of PPV and stored at -80°C. Samples from 13 patients who developed PVR within 6months (PVR group) and 13 age- and gender-matched controls who did not develop PVR (control group) were included. Protein abundance levels were evaluated using a proximity extension assay, and a confirmatory enzyme-linked immunosorbent assay (ELISA) was used to measure the concentration of vimentin. Baseline vimentin (Normalized Protein eXpression [NPX], 8.6 vs. 6.4, P < 0.0001) and heme oxygenase 1 (NPX 8.9 vs. 7.0, P < 0.001) levels were found to be elevated in vitreous fluid of patients who subsequently developed PVR compared to those who did not. Confirmatory analysis using ELISA demonstrated mean vimentin concentrations of 7254 vs. 2727 ng/mL in the PVR versus control groups (P = 0.0152). The odds ratio for developing PVR was 14 (confidence interval, 1.4-168; P = 0.03), assuming a baseline vimentin threshold of 7500 ng/mL. Vimentin is an intermediate filament protein expressed by retinal glial cells, and our data combined with prior evidence suggest that it may serve as an early vitreous biomarker for subsequent PVR formation and reactive gliosis. Furthermore, we found, for the first time, elevated baseline levels of heme oxygenase 1, a measurable indicator of oxidative stress. Our positive findings could impact clinical care for retinal detachment patients by facilitating risk stratification for targeted interventions or closer monitoring in those at the highest risk of developing PVR.

Short-course neoadjuvant radiotherapy combined with chemotherapy and toripalimab for locally advanced esophageal squamous cell carcinoma (SCALE-1): a single-arm phase Ib clinical trial

BackgroundThe optimal dosages, timing, and treatment sequencing for standard-of-care neoadjuvant chemoradiotherapy necessitate re-evaluation when used in conjunction with immune checkpoint inhibitors for patients with resectable, locally advanced esophageal squamous cell...

Pharmacokinetics and coagulation biomarkers in children and adults with hemophilia A receiving emicizumab prophylaxis every 1, 2, or 4 weeks

BackgroundEmicizumab is a bispecific antibody that bridges activated factor (F)IX and FX, mimicking the function of missing activated FVIII and thus improving hemostasis in people with hemophilia A. The efficacy and safety of emicizumab were demonstrated in 4 phase III clinical trials (HAVEN 1-4). ObjectivesHere, we describe pharmacokinetics (PKs), pharmacodynamics (PDs), and exploratory safety biomarkers in HAVEN 1 to 4. MethodsParticipants received emicizumab at a loading dose of 3 mg/kg weekly for 4 weeks, followed by maintenance doses of 1.5 mg/kg weekly, 3 mg/kg every 2 weeks, or 6 mg/kg every 4 weeks. PKs, PDs, and safety biomarkers were assessed in samples collected at regular intervals during the trials. ResultsEmicizumab plasma trough concentrations increased during the loading dose period, reaching a mean of 52.9 μg/mL (SD, 13.6 μg/mL) at week 5, and were sustained at 42.1 to 52.3 μg/mL thereafter with maintenance dosing. Activated partial thromboplastin time shortened following the first emicizumab dose. Mean FVIII-like activity and thrombin generation peak height increased to 25.2 IU/dL (SD, 6.9 IU/dL) and 115.2 nM (SD, 42.5 nM) at week 5, with levels sustained at 17 to 23 IU/dL and >116 nM thereafter, respectively. Emicizumab did not notably affect FIX or FX plasma antigen levels, prothrombin time, or concentrations of exploratory safety markers of coagulation activation (D-dimer, prothrombin fragment 1 + 2, and fibrinogen). ConclusionIn HAVEN 1 to 4, emicizumab demonstrated sustained PKs and PDs and improved coagulation parameters without affecting safety biomarkers.

Detectable ctDNA at the time of treatment cessation of ipilimumab and nivolumab for toxicity predicts disease progression in advanced melanoma patients.

Immune checkpoint inhibition (ICI) has led to unprecedented outcomes for melanoma patients but is associated with toxicity. ICI resumption after high grade irAEs poses a significant challenge in the clinical management of melanoma patients and there are no biomarkers that can help identify patients that might benefit from resuming treatment. This study aims to determine if circulating tumor DNA (ctDNA) levels at the time of treatment-limiting irAE could guide treatment decisions in this clinical context. This is a retrospective exploratory biomarker study from 34 patients treated with combination ICI for stage IV melanoma. Patients had a treatment-limiting toxicity and a baseline plasma collection prior to commencing ICI and within 6 weeks of stopping therapy. Blood samples were tested for ctDNA at baseline and cessation therapy. Median progression free survival (PFS) and overall survival (OS) have not been reached (24-month PFS rate 54% and OS rate 72.3%). PD occurred in 47% (16/34) of patients. Median PFS with detectable ctDNA from plasma collected at the time of toxicity was 6.5 months while not reached (NR) with undetectable levels (HR: 4.0, 95% CI 0.95-17.5, p=0.0023). Median OS with detectable ctDNA at cessation for toxicity was 19.4 months and NR for undetectable ctDNA (HR: 3.9, 95%CI 20.8-18.6, p=0.024). Positive ctDNA at the time of cessation was highly specific (specificity 0.94, 95% CI 0.74-0.99, PPV 0.88, 95% CI 0.53-0.99). However, ctDNA negativity has low sensitivity as a predictor of ongoing disease control (sensitivity 0.437, 95% CI 0.23-0.67). Notably, 4/9 (44%) ctDNA negative patients who had disease progression had brain only disease progression. Undetectable ctDNA and CR on imaging after stopping immunotherapy for toxicity results in high rates of long-term durable control. For patients with immunotherapy related toxicity, who have persistent ctDNA at 8 - 12 weeks, the risk of disease progression is significant.

Abstract C008: Phase I biomarker analysis of farletuzumab ecteribulin (FZEC), formerly MORAb-202, effects on cancer responses in patients with platinum resistant ovarian cancer

Abstract Background: FZEC (formerly MORAb-202) is an antibody-drug conjugate consisting of farletuzumab and eribulin. FZEC is cytotoxic to FRα+ cancer cells (via direct binding) and to adjacent tumor cells (via bystander effects); it also exerts noncytotoxic bystander effects in the tumor microenvironment (Zhang et al, EORTC 2022). Study 101 is a first-in-human dose escalation followed by dose expansion study in Japanese patients (pts) with selected solid tumors to determine safety and preliminary efficacy of FZEC; antitumor activity across several doses was demonstrated in pts with platinum-resistant ovarian cancer (PROC) and FRα+ tumors (Nishio ASCO 2022). This exploratory biomarker study evaluated association of FZEC-induced pharmacological effects and clinical responses in pts with PROC to examine the mechanism of action (MoA) of FZEC. Methods: Serum samples from up to 58 pts with PROC from a FZEC 0.9 mg/kg cohort (equivalent to 33 mg/m2) or from a combined dose cohort (FZEC 0.3, 0.45, 0.68, 0.9, 1.2 mg/kg) were collected predose on day 1 of treatment cycles 1–6 and analyzed using 139 exploratory Luminex, Simoa, or OLINK protein assays. While these doses are no longer being evaluated, as a result of a change to body-surface-area-based dosing, the biomarkers observed to be preliminarily associated with response in this analysis should be further explored in ongoing studies. Markers with &amp;gt;30% unevaluable data points were excluded. The 1-sample Wilcoxon signed-rank test and 2-sample Wilcoxon rank-sum test were used to assess changes from baseline and differences between 2 best overall response groups (responders [CR/PR] and nonresponders [SD/PD]) at each visit. Fisher’s method was used to summarize statistical difference across visits (meta P&amp;lt;0.05) between the 2 groups. Results: Changes from baseline to at least 1 visit postdose (P&amp;lt;0.05) in either the responder or nonresponder groups, and differences between responders and nonresponders (meta P&amp;lt;0.05), were seen in 29 markers in the combined-dose cohort, and in 14 markers in the 0.9 mg/kg cohort. There was an overlap of 11 markers in both the FZEC 0.9 mg/kg and combined-dose cohorts that showed a significant change from baseline and significant differences in changes between responders and nonresponders. Among these 11 markers, SP-D and IGFBP-2 showed persistent changes (≥3 visits) in responders. Decreases in markers with reported protumor functions (eg, ANG-2, KLK-5, KLK-7, MCP-1, FRTN, and MMP-12), and increases in SP-D, were persistent (≥4 of 5 visits) in responders. Some biomarkers (eg, IGFBP-1, FLT3LG, and VEGF-D) showed significant increases in nonresponders. Conclusions: The persistent responder-associated biomarker changes suggest that FZEC may modulate functions associated with these markers (eg, immune regulation, vascular remodeling, extracellular matrix protease activities, iron metabolism) and this may contribute to the antitumor effect of FZEC. In the limited number of pts analyzed, preliminary pharmacodynamic effects trended with the antitumor effects observed with FZEC 0.9 mg/kg. Citation Format: Yan Zhang, Bob Zimmermann, Shuyu Li, Toshimitsu Uenaka, Keiji Furuuchi, Kan Yonemori, Toshio Shimizu, Shin Nishio, Mayu Yunokawa, Koji Matsumoto, Kazuhiro Takehara, Kosei Hasegawa, Yasuyuki Hirashima, Hidenori Kato, Yohei Otake, Takuma Miura, Junji Matsui, Meijuan Li. Phase I biomarker analysis of farletuzumab ecteribulin (FZEC), formerly MORAb-202, effects on cancer responses in patients with platinum resistant ovarian cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C008.