Citations

Abstract Purpose: The addition of MEK inhibition (MEKi) to programmed cell death ligand 1 (PD-L1) blockade improves progression-free survival (PFS) in patients with advanced biliary tract cancer. Although MEK inhibitors may increase tumor cell immunogenicity, they can impair T-cell priming/effector function, limiting combination efficacy. We hypothesized that the addition of a CD27 agonist could restore T-cell function and enhance antitumor immunity in this combination. Patients and Methods: We conducted a randomized, phase II trial evaluating atezolizumab (840 mg, intravenously, days 1 and 15) in combination with the CD27 costimulatory monoclonal antibody [CDX-1127/varlilumab (3 mg/kg, intravenously, days 1 and 15)], with/without the addition of an MEK inhibitor [cobimetinib (60 mg, orally, daily, days 1–21, off days 22–28)] in unresectable biliary tract cancer following at least one metastatic therapy. Overall response rate (ORR) and PFS were coprimary endpoints. Treatment-related changes in CD8+ tumor-infiltrating lymphocytes (TIL) were the primary correlative outcomes. Results: The trial was closed early following interim preplanned ORR analysis. At closure, 57 patients had been enrolled [n = 29 in the cobimetinib + atezolizumab + varlilumab (CAV) arm; n = 28 in the atezolizumab + varlilumab (AV) arm]. A majority (67%) had intrahepatic cholangiocarcinoma, and 32% were immunotherapy experienced. Both regimens were well tolerated without new safety signals. Objective responses were rare [0% (CAV); 3.8% (AV)]. The median PFS (mPFS) was 2.40 (CAV) and 1.84 (AV) months [hazard ratio (HR), 0.67; 95% confidence interval (CI), 0.38–1.18]. Among immunotherapy-experienced patients, the mPFS was 3.62 (CAV) and 1.84 (AV) months (HR, 0.54; 95% CI, 0.18–1.62). Treatment with CAV increased intratumoral CD8+ T-cell density compared with treatment with AV. Conclusions: The combinations of atezolizumab and varlilumab with/without cobimetinib were safe, but neither meaningfully improved outcomes in biliary tract cancer treated in the later lines. Correlative tissue studies validated preclinical work that MEKi increases CD8+ TILs.

Background Cysteine–cysteine chemokine receptors 2 (CCR2) and 5 (CCR5) contribute to immune suppression in tumor microenvironments. CCR2 and CCR5 antagonists have demonstrated antitumor activity in pancreatic ductal adenocarcinoma (PDAC) and colorectal cancer (CRC), respectively. This phase 1b/2, open-label study evaluated BMS-813160, a CCR2/5 dual antagonist, in combination with chemotherapy±nivolumab in advanced PDAC or metastatic CRC. Methods Part 1 included patients with metastatic untreated (first-line (1L)) PDAC, 1L CRC, or previously treated (second or third line (2/3L)) microsatellite stable (MSS) CRC. Patients received 2 weeks of BMS-813160 monotherapy (300 mg two times a day, 600 mg once daily, 300 mg once daily, or 150 mg once daily) and then BMS-813160+chemotherapy (gemcitabine+nab-paclitaxel (gem/nabP; 1L PDAC), 5-fluorouracil+leucovorin+irinotecan (FOLFIRI; 1L CRC)), or nivolumab (2/3L MSS CRC). Part 2 included patients with metastatic 1L PDAC or 2L CRC. Patients received BMS-813160 300 mg two times a day+gem/nabP±nivolumab (1L PDAC), BMS-813160 300 mg two times a day or 150 mg once daily+FOLFIRI (2L CRC), or chemotherapy alone. Primary endpoints were safety and pharmacodynamics (Part 1) and efficacy (Part 2). Results In Part 1, 22 of 75 (29%) and 54 of 72 (72%) patients experienced a treatment-related adverse event during monotherapy lead-in and overall, respectively. Two dose-limiting toxicities (rash and pericardial effusion with pericarditis, both grade 3) occurred. In Part 2, patients with 1L PDAC who received BMS-813160 300 mg two times a day+gem/nabP+nivolumab achieved an overall response rate (ORR) of 37% (13/35); the median duration of response (DOR) was 45 weeks (95% CI 26.1 to not evaluable). ORRs with BMS-813160 300 mg two times a day+gem/nabP and gem/nabP alone were 26% (9/35) and 28% (9/32), respectively; median DORs were 121 and 31 weeks, respectively. Progression-free survival rates at 24 weeks were 56% (BMS-813160 300 mg two times a day+gem/nabP+nivolumab), 56% (BMS-813160 300 mg two times a day+gem/nabP), and 50% (gem/nabP). ORRs in 2L CRC were 19% (6/32; BMS-813160 300 mg two times a day+FOLFIRI), 13% (4/32; BMS-813160 150 mg once daily+FOLFIRI), and 27% (7/26; FOLFIRI). Conclusions In 1L PDAC, BMS-813160 300 two times a day+gem/nabP±nivolumab demonstrated durable antitumor response and was well tolerated. BMS-813160 combination regimens were tolerable in other cohorts, but clinical efficacy was not demonstrated. Trial registration number NCT03184870 .

Objective: In this study, we evaluate the utility of ctDNA analysis in a large cohort of patients for whom ctDNA testing was ordered commercially with real-world application. Summary Background Data: Circulating tumor DNA (ctDNA) has emerged as a prognostic and predictive biomarker for assessing post-surgical molecular residual disease (MRD) and response to treatment. Methods: A real-world data analysis was performed using commercial ctDNA testing (SignateraTM) from patients (N=795, n=5,971 plasma samples) with stage I-III colon cancer treated at multiple US institutions. The association of ctDNA detection within the MRD window, during surveillance, and the impact of ACT was correlated with patient outcomes. Results: ctDNA-positive patients during the MRD window and surveillance showed significantly shorter DFS compared to ctDNA-negative patients (hazard ratio (HR): 9.85, P<0.0001; HR: 26.91, P<0.0001). Multivariate analysis of the MRD window revealed ctDNA-positivity as the most significant factor associated with inferior DFS (adjHR: 7.7, P<0.001). MRD-positive patients who received ACT showed improved DFS compared to patients observed post-surgery (adjHR: 6.1, FDR adj P=0.0007). No ACT benefit was observed in MRD-negative patients (adj HR: 1.20, FDR adj P=0.768). On evaluating ctDNA dynamics from MRD to surveillance, patients who remained ctDNA-positive or converted from negative to positive showed a significantly inferior DFS (HR: 34.40, P<0.0001; HR: 13.65, P<0.0001) compared to persistently ctDNA-negative patients. Conclusions: Postsurgical ctDNA detection is prognostic of relapse and potentially predictive of ACT benefit in patients with resectable colon cancer, which may enable personalized surveillance, intervention, and/or trial options, ultimately improving patient outcomes.

Background: Historically, the standard of care for advanced biliary tract cancers (aBTCs) was gemcitabine plus cisplatin (GemCis). Immunotherapy plus GemCis is now recommended as a first-line treatment for aBTCs. Whether patients can tolerate eight cycles of GemCis in clinical practice, as per the Advanced Biliary Cancer (ABC)-02 study, remains to be assessed. We performed a retrospective observational cohort study to assess real-world treatment patterns and overall survival (OS) in patients with de novo or recurrent aBTCs treated with first-line gemcitabine-based chemotherapy in the United States. Methods: This retrospective observational cohort study used Optum’s de-identified Market Clarity Data (Market Clarity). Adults diagnosed with de novo or recurrent aBTCs in the United States who began first-line gemcitabine-based chemotherapy from January 2016–March 2022 were identified and followed from index until death, the end of continuous enrolment, or the end of study period. Treatment patterns and OS were assessed. Results: Overall, 559 patients were included (de novo, n = 462; recurrent, n = 97). GemCis was the most common first-line therapy received (de novo: 73.8%; recurrent: 57.7%). Most patients received approximately five cycles of GemCis; median (95% CI) time to discontinuation was 4.6 (4.3–5.1) months. Most patients died over the follow-up period (de novo: 70.3%; recurrent: 62.9%). Median OS (95% CI) was 14.2 (12.1–16.1) months (de novo) and 18.5 (15.6–26.9) months (recurrent). Conclusions: GemCis was the most common first-line therapy received during the study period; most patients were unable to receive eight cycles of GemCis. Survival was limited over the follow-up period, highlighting the need for new treatments for aBTCs. Future studies are warranted to understand the real-world impact of first-line immunotherapy plus GemCis for patients with aBTCs.

TPS2675 Background: Checkpoint inhibitor therapy is the standard first-line treatment for advanced/recurrent HCC, but there is a significant unmet therapeutic need for patients (pts) who progress after first-line treatment. Adoptive cellular immunotherapy may provide a novel treatment option. Glypican-3 (GPC3), a heparan sulfate proteoglycan, is overexpressed by tumor cells in HCC and virtually absent in healthy tissues, making it an ideal target for CAR-T therapy. AZD5851 is an autologous CAR-T product that expresses a CAR specific for GPC3 and a dominant negative (dn)TGFβRII as an armoring strategy. Expression of dnTGFβRII can block TGFβ signaling, protecting CAR T-cells from the immunosuppressive effects of this cytokine. Early clinical data with C-CAR031, a CAR-T product with the same GPC3-specific CAR and dnTGFβRII-armoring transgene as AZD5851, showed promising tolerability and antitumor activity in pts with HCC [1]. ATHENA (NCT06084884) is a first-in-human, single-arm, open-label, multicenter phase 1/2 study to evaluate the safety, tolerability, and antitumor activity of AZD5851 in pts with GPC3+ advanced/recurrent HCC, for whom ≥1 prior line of standard therapy failed or was not tolerable. Methods: Eligible pts are aged ≥18 years with histologically confirmed advanced/recurrent or metastatic and/or unresectable HCC, GPC3+ tumor sample as determined by immunohistochemistry, ≥1 prior line of standard systemic therapy, ≥1 measurable lesion per RECIST 1.1, Child-Pugh A, ECOG PS 0/1, and adequate organ and bone marrow function. Approximately 24 pts will be enrolled in Part A (Phase I, dose escalation) and 50 in Part B (Phase II dose expansion). Pts will undergo apheresis to collect peripheral blood mononuclear cells for AZD5851 production, after which they may receive approved bridging therapy for disease control. Upon successful generation of AZD5851 product, pts will undergo lymphodepletion before receiving a single dose of IV AZD5851. Subsequent follow-up is divided into 3 stages: Stage 1, active follow-up of all pts through 6 months post AZD5851 infusion; Stage 2, further evaluation of pts who have not progressed or started a new anticancer regimen during Stage 1; Stage 3, long-term follow-up for all pts who have received AZD5851. The primary endpoints are to assess the safety/tolerability of AZD5851 (both study parts), and to determine the recommended dose(s) of AZD5851 for expansion and phase 2 trials (Part A). Secondary endpoints include efficacy (objective response rate, best overall response, duration of response, disease control rate, durable response rate, time to response, progression-free survival, and overall survival) and pharmacokinetics. Exploratory endpoints include pharmacodynamic biomarkers and immunogenicity. Enrollment began Nov 2023. 1. Zhang et al. AACR 2023. Abstract CT097. Clinical trial information: NCT06084884 .

Y-90 Selective Internal Radiotherapy (SIRT) is an ablative therapy used for inoperable liver metastasis. The purpose of this investigation was to examine the impact of local control after SIRT on overall survival (OS) in oligometastatic patients. A retrospective, single-institution study identified oligometastatic patients with ≤5 non-intracranial metastases receiving unilateral or bilateral lobar Y-90 SIRT from 2009 to 2021. The primary endpoint was OS defined from Y-90 SIRT completion to the date of death or last follow-up. Local failure was classified as a progressive disease at the target lesion(s) by RECIST v1.1 criteria starting at 3 months after SIRT. With a median follow-up of 15.7 months, 33 patients were identified who had a total of 79 oligometastatic lesions treated with SIRT, with the majority histology of colorectal adenocarcinoma (n = 22). In total, 94% of patients completed the Y-90 lobectomy. Of the 79 individual lesions treated, 22 (27.8%) failed. Thirteen patients received salvage liver-directed therapy following intrahepatic failure; ten received repeat SIRT. Median OS (mOS) was 20.1 months, and 12-month OS was 68.2%. Intralesional failure was associated with worse 1 y OS (52.3% vs. 86.2%, p = 0.004). These results suggest that intralesional failure following Y-90 may be associated with inferior OS, emphasizing the importance of disease control in low-metastatic-burden patients.

4017 Background: Combined MEK inhibition (MEKi) and PD-L1 blockade significantly improved progression-free survival (PFS) versus PD-L1 monotherapy in patients with advanced biliary tract cancer (BTC) following first-line chemotherapy (NCT03201458). Further study has shown MEKi enhances tumor immunogenicity but impairs host T cell activation/priming. The addition of immune agonists, e.g. a CD27 agonist, can rescue T cell function in the setting of systemic MEKi in vivo and may be an effective strategy to optimize MEKi’s immunomodulatory potential when used in combination with checkpoint blockade. Methods: We conducted a randomized ph 2 trial (NCT04941287) evaluating Atezolizumab in combination with the CD27 immune agonist (CDX-1127 [Varlilumab]) with or without the addition of a MEKi (Cobimetinib) in patients with unresectable, previously treated, BTC. Adults with pathologically-confirmed BTC, s/p at least 1 prior line (no more than 2) of systemic therapy, measurable disease, and ECOG PS ≤1 were enrolled. Patients who had received previous PD-[L]1 were eligible. The study was planned for 64 evaluable subjects randomized in a 1:1 ratio, stratified by BTC site, to either AV (Atezolizumab [840mg IV days 1,15])+ Varlilumab [3mg/kg IV days 1, 15]) or CAV (Cobimetinib [60mg oral daily days 1-21, off 22-28] + Atezolizumab + Varlilumab). Overall response rate (ORR) and PFS were co-primary endpoints. The primary correlative outcome was treatment-related changes in CD8+ infiltrating T cells. Results: A preplanned interim analysis based on objective response rates did not meet the threshold for continuance in either treatment arm, so the trial was closed early for futility. In total, 57 patients were enrolled (n = 29 [CAV], n = 28 [AV], 67% had intrahepatic cholangiocarcinoma, and 33% had received previous PD-[L]1. Both CAV and AV regimens were well-tolerated without new safety signals. Adding CDX-1127 did not appear to meaningful increase immunotoxicity beyond established PD-L1 toxicity profiles. ORR was 0% (CAV) and 4% (AV). With a median follow up time of 6.2 months, median PFS was 2.2 (CAV) and 1.8 (AV) months (HR 0.71 [0.40,1.25]). In PD[L]1-experienced patients, median PFS was 3.6 (CAV) and 1.7 (AV) months (HR 0.44 [0.14,1.33]). Median OS was 10.2 (CAV) and 6.1 (AV) months (HR 0.76 [0.37,1.55]). In PD[L]1-experienced patients, median OS was 6.4 (CAV) and 4.4 (AV) months for CAV and AV (HR 0.68 [0.19,2.42]). Primary correlative endpoint and updated survival will be reported at time of meeting. Conclusions: The combination of Atezolizumab and Varlilumab with or without Cobimetinib was safe but did not improve clinical outcomes in advanced stage BTC patients treated in later lines. Though not statistically significant, treatment with CAV demonstrated numerically favorable PFS/OS compared AV among immunotherapy-experienced patients. Clinical trial information: NCT03201458 .

3077 Background: ATR protein kinase is activated by replication stress and recruited to stalled forks or single strand DNA defects in various cancers. The topoisomerase-I (Top1) inhibitor irinotecan induces DNA damage. The ATR inhibitor BAY1895344 (elimusertib) has demonstrated cytotoxic potential in SCLC and GI cancer xenografts when combined with Top1 inhibitors . Methods: This phase Ia trial assessed elimusertib in combination with irinotecan in adult patients with refractory advanced solid tumors for whom irinotecan can be considered standard care. Patients with previous irinotecan exposure were excluded. Two dosing schedules were used: 1) Biweekly - irinotecan IV (starting at 150 mg/m2) D1 + elimusertib (starting dose 20 mg PO BID) D1,D2 (cycle=14 days); 2) Weekly - irinotecan (starting at 50 mg/m2) IV on D1,8,15 with elimusertib (starting at 20 mg PO daily) on D2,D3,D9,D10 and D16,D17 (cycle=21 days). Dose escalation utilized a 3+3 design. Primary objectives were to assess safety and tolerability and estimate the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D). Secondary objectives included estimating pharmacokinetic (PK) profiles and assessing anti-tumor activity. Results: A total of 21 patients were enrolled in dose escalation (N=9 [Biweekly] and N=12 [Weekly], median age 58 and 2 lines of prior therapy. For the Biweekly cohort: 3/3 patients enrolled at dose level (DL) 1 experienced hematologic dose-limiting toxicity (DLT); 6 patients received DL-1 without any DLTs. The weekly regimen escalation comprised of 12 patients: 6 enrolled in DL1 with 2/6 having hematologic DLT and 5/6 unable to complete ≥75% of cycle 1 dosing; 6 enrolled in DL-1 with no DLTs observed. Notable grade 3+ treatment-related adverse events and summary best response are summarized (Table 1). The majority of evaluable patients in both schedules had initial disease control (56% [biweekly] and 67% [weekly]). One confirmed partial response was seen in the biweekly RP2D. Median progression-free survival was 2.1 mo [biweekly] and 2.5 mo [weekly]. PK results will be presented at time of meeting. Conclusions: Both RP2D and MTD of elimusertib in combination with irinotecan were reached for both dosing schedules: irinotecan 150 mg/m2 IV D1 + elimusertib 10 mg BID PO D1,D2 (biweekly) and irinotecan 25 mg/m2 IV on D1 + elimusertib (20 mg PO daily) on D2,D3 (weekly). Dose escalation was notably limited by myelotoxicity. Due to sponsor decision, the study was halted prior to planned expansion but the concept of ATR + topo I combination remains scientifically relevant. Clinical trial information: NCT04514497 . [Table: see text]

Abstract Background: Fibroblast growth factor receptor (FGFR) alterations occur across various malignancies and are potent oncogenic drivers in multiple tumor types. FGFR inhibitors have demonstrated efficacy in several cancers with FGFR alterations. Tinengotinib is a novel kinase inhibitor with high potency to a variety of FGFR 1/2/3 kinase domain mutations and has shown promising efficacy in several ongoing clinical studies. Here, we present pooled data of tinengotinib in previously treated solid tumor patients (pts) with actionable FGFR1-3 mutations from four trials (NCT03654547, NCT04742959, NCT04919642, NCT05253053). Methods: Eligible pts received tinengotinib orally once daily (daily dose ranging from 5-12mg) until disease progression. Analyses of best overall response (BOR) rate, disease control rate (DCR), median progression-free survival (mPFS), median duration of response (mDOR) and treatment-related adverse events (TRAEs) were performed. Results: As of 3-Aug-2023, 53 solid tumor pts with actionable FGFR1-3 mutations were enrolled between Dec-2019 to Aug-2023 in the US and China. The median follow-up time was 14.5 (range, 3.3-43.8) months. Median age was 58 years (range, 29-83). Most pts were female (62%), had ECOG of 1 (68%) and were heavily pretreated with 55% having ≥3 lines of prior antitumor therapy. The most frequent FGFR mutation enrolled was in FGFR2 (77%) followed by FGFR1 (19%) and FGFR3 (11%). 25 pts (47%) had received prior therapy with FGFR inhibitor. A total of 45 pts were efficacy-evaluable, including cholangiocarcinoma (CCA, n=25), colon cancer (n=5), breast cancer (n=3), prostate cancer (n=3), head and neck cancer (n=3), urothelial cancer (n=3), pancreatic cancer (n=1), gastric cancer (n=1) and leiomyosarcoma (n=1). mPFS reached 6.83 (95% CI, 4.90-8.34) months. Partial responses were observed in 16/45 (35.6%) pts across 6 distinct tumor types, including CCA, breast, prostate, urothelium, colon and head and neck cancer. mDOR was 6.74 (95% CI, 3.52-9.46) months. For 44 pts with measurable target lesions per RECISTv1.1, the BOR rate and DCR were 36.4% and 86.4%, respectively. For 22 pts with prior FGFR inhibitor, mPFS was 5.98 (95% CI, 3.75-9.10) months and their BOR rate and DCR were 40.9% and 86.4%. TRAEs were reported in 46 (86.8%) pts, with 13 (24.5%) Grade (G) 1-2, 30 (56.6%) G3, 2 (3.8%) G4, and no G5. The most common TRAEs (≥20%) were hypertension, stomatitis, diarrhea, nausea, blood thyroid stimulating hormone increased, fatigue and anemia. Side effects were manageable and reversible with dose hold and/or dose reduction. Conclusions: We observed promising clinical benefit with tinengotinib in heavily pretreated solid tumor pts with FGFR1-3 mutations. The side effects profile was manageable and no new safety signals have been identified. Further research is planned to evaluate the safety and efficacy of tinengotinib in pts with FGFR1-3 mutations across a wider variety of tumor types. Citation Format: Sarina A. Piha-Paul, Chih-Yi "Andy" Liao, Lionel Fonkoua, Amit MahipaI, Sanjay Goel, Christos Fountzilas, Lin Shen, Daneng Li, Dustin Deming, Farshid Dayyani, Weiqing Han, Zuoxing Niu, Jean Fan, Peng Peng, Hui Wang, Peng Huang, Frank Wu, Milind Javle. Tinengotinib in patients with advanced solid tumors harboring actionable FGFR1-3 mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB162.

454 Background: Biliary tract cancers (BTC) are often diagnosed at advanced stages (aBTC) when prognosis is poor. In the Phase 3 TOPAZ-1 study (NCT03875235), durvalumab plus gemcitabine and cisplatin (GemCis) significantly improved overall survival versus placebo plus GemCis. To better understand the context of the TOPAZ-1 trial results in the US, we looked at first-line (1L) treatment patterns in participants with aBTC treated with GemCis and other gemcitabine (Gem)-based chemotherapy (CT) regimens. Methods: This retrospective observational cohort study used linked electronic health records and medical and pharmacy claims data from the Optum Market Clarity Database. Adults diagnosed with de novo or recurrent aBTC, who initiated 1L Gem-based CT between January 2016 and March 2022, were identified and followed from the index date (defined as the first administration of Gem-based CT on or after initial BTC diagnosis date) until death, end of continuous enrollment, or end of study period, whichever occurred first. Variables including patient demographics, clinical characteristics, and treatment patterns were described. Results: A total of 580 patients were included in the analysis with either de novo aBTC (n=481, 82.9%) or recurrent aBTC (n=99, 17.1%) with median follow-up time of 10.4 (interquartile range: 6.4, 17.5) and 12.0 (interquartile range: 6.3, 21.9) months, respectively. Mean (SD) age was 64.6 (11.2) and 66.8 (10.4) years, with 45.7% and 54.5% male in the de novo and recurrent aBTC groups, respectively. Most patients were white (77.6%). The most frequent site of primary tumor diagnosis was single-site intrahepatic (overall 62.8%, de novo 66.7%, recurrent 43.4%). In the 12 months prior to index date, 38.5% of patients had biliary obstruction, 30.2% had biliary stents, 29.3% had jaundice, and 17.1% had nonalcoholic fatty liver disease/nonalcoholic steatohepatitis. Common comorbidities included cardiovascular disease (50.9%), obesity (46.8%), and diabetes (35.2%). The most common 1L CT was GemCis followed by Gem for both the de novo (n=355, 73.8% and n=36, 7.5%) and recurrent groups (n=58, 58.6% and n=26, 26.3%), respectively. Approximately half of participants (50.9%) switched to a new line of treatment, 33.3% discontinued 1L CT, and 15.9% remained on 1L CT at last follow-up. Most frequent 2L treatments included fluorouracil/oxaliplatin (36.9%) and capecitabine (14.2%). Further analysis will characterize outcomes and regimen duration. Conclusions: Findings from this retrospective study showed that the most common 1L therapies were GemCis and Gem among both de novo and recurrent patients with aBTC. These results provide insight into aBTC treatment practices and may help inform treatment decisions.