Citations

TPS2673 Background: The main challenge for developing CAR T therapies for solid tumors is the lack of targets that distinguish tumor from normal cells, resulting in on-target, off-tumor toxicity. Tmod logic-gated CAR T therapy addresses this challenge by incorporating 2 CARs on the same T cell: an activator targeting a marker on both tumor and normal cells, and a blocker targeting HLA-A*02 that inhibits CAR T activity against normal cells while allowing activation against tumor cells (with HLA-A*02 LOH), improving tumor selectivity and decreasing toxicity. Early safety results from 3 ongoing phase 1/2 clinical trials of logic-gated, Tmod CAR T therapy (EVEREST-1, EVEREST-2, and DENALI-1) have demonstrated manageable safety and tolerability in patients with advanced solid tumors (Grierson et al, SITC , 2024; Ward et al, SITC 2025; Specht et al, SABCS , 2025). Early efficacy results include the first ever reported complete response in a patient with non-small cell lung cancer following treatment with a CAR T-cell therapy (A2B694). A2B543 is an autologous Tmod CAR T therapy that contains the same Tmod construct as A2B694 with an added membrane-tethered IL-12 (memIL12) booster. Specifically, A2B543 is comprised of autologous Tmod cells transduced with 2 lentiviral vectors: one expressing both the HLA-A*02-targeted blocker and the mesothelin-targeted CAR activator; and a second expressing the memIL12 booster. Interleukin 12 (IL-12) is a potent, pro-inflammatory cytokine that plays a crucial role in inducing antitumor immune responses; however, systemic IL-12 can be prohibitively toxic (Jia et al, Front Immunol , 2022). In A2B543, expression of the memIL12 cassette is under the control of an NFAT promoter and is induced during antigen engagement or T cell activation. This inducible memIL12 is designed to reduce the toxicity associated with systemic IL-12 while enhancing the long-term potency and persistence of Tmod (Zhang et al, J Immunother Cancer , 2025). Methods: EVEREST-2 (NCT06051695) is a phase 1/2, open-label, nonrandomized study evaluating the safety and efficacy of A2B543 in adults with recurrent/metastatic mesothelin-expressing cancers with tumor-associated HLA-A*02 LOH, including mesothelioma, colorectal, non-small cell lung, pancreatic, or ovarian cancer. Patients are enrolled through BASECAMP-1 (NCT04981119), a master prescreening study that identifies patients with HLA LOH via next-generation sequencing and cryopreserves leukapheresis product. Upon progression, A2B543 is manufactured and then administered after lymphodepletion. The phase 1 primary objective is to evaluate the safety and tolerability of A2B543 and identify a recommended phase 2 dose (RP2D). The phase 2 primary objective is to assess overall response rate. Clinical trial information: NCT06051695 .

TPS1679 Background: Cancer care in the United States remains highly centralized, imposing substantial time, caregiver, and financial burdens on patients, particularly those residing in rural and medically underserved regions. While international experience supports the feasibility of home-based cancer therapy delivery, prospective U.S. clinical trial data are limited. The Cancer CARE Beyond Walls (CCBW) program was developed to address these gaps through a decentralized cancer care model integrating virtual oversight, remote monitoring, mobile clinical services, and community-based nursing partners. The study evaluates the feasibility, safety, and patient-centered impact of delivering cancer-directed therapy in patients’ homes or near-home mobile units in the Florida Panhandle, a region characterized by long travel distances to tertiary centers and limited oncology infrastructure. Methods: This is a phase 2, single-arm clinical trial evaluating the delivery of standard-of-care cancer-directed therapy outside of traditional infusion centers. Eligible adult patients (ECOG 0–3) with histologically confirmed malignancies receiving guideline-supported or FDA-approved systemic cancer therapy must demonstrate tolerability of at least one prior in-clinic treatment cycle. Following registration, patients transition to home-based or near-home mobile unit administration for a minimum of 12 weeks, with an option to continue up to 24 weeks. Care delivery is coordinated through a virtual command center providing real-time virtual oversight, remote monitoring, and escalation pathways. Treatment administration is performed by trained local home health nurses, medication shipping, and digital interaction with the electronic health record. A fully equipped mobile unit extends access to rural areas not covered by home health agencies. The primary endpoint is patient preference for treatment location at week 12. Secondary endpoints include safety, avoidable acute care utilization, patient-reported function and global health/quality of life, patient-reported symptoms, and satisfaction with care. Exploratory endpoints assess travel burden, patient perceptions of caregiver experience, and patient perceptions of home versus mobile unit care. Enrollment of 27 patients will provide 80% power to reject a 50% null rate (2-sided exact test, α=0.10), assuming 75% prefer decentralized care or express no preference. This investigator-initiated trial is open to accrual and is supported by a grant from the Florida Cancer Innovation Fund. Clinical trial information: NCT07285044 .

e18026 Background: Immune checkpoint inhibitor (ICI) therapy is part of standard of care first-line therapy for recurrent or metastatic (R/M) HNSCC. However, less than 20% of patients (CPS ≥1) have an objective response to ICI monotherapy, and most tumors progress within ~3 months. We sought to improve the proportion of patients who benefit from a chemotherapy-free regimen by combining intratumoral (IT) VV1 oncolytic virus (VSV-IFNβ-NIS) injections with the anti-PD-1 antibody, cemiplimab. We report a pre-planned analysis of Simon's stage 1 results. Methods: We activated a phase 2 study testing the efficacy of first line IT VV1 plus cemiplimab in 1 st line patients with R/M HNSCC. A Simon's two-stage design was employed whereby 10 patients would be accrued in stage 1, and if 3 or more responses were observed, 12 additional patients would be accrued for stage 2. The primary endpoint was objective response rate (ORR) per investigator (RECIST 1.1). Eligible patients had untreated R/M HNSCC from primary oropharynx, oral cavity, hypopharynx, or larynx sites with CPS ≥1. Patients had to have at least one measurable lesion amenable to IT injection. Treatment comprised of IT injections to 1-5 lesions of oncolytic VV-1 virus and IV cemiplimab 350 mg on day 1, repeated every 21 days. Each lesion could be injected 3 times; a 4th injection was allowed if a partial response (PR) was achieved after 3 injections. Cemiplimab could be continued for up to 2 years until progression or unacceptable toxicity. Results: Patient and tumor characteristics, as well as efficacy and toxicity are summarized in the table below. Ten patients were treated at the time of Stage 1 analysis, with 3 showing a confirmed PR for ORR of 30%. Responder CPS scores were 45, 12 and 20%. Two of the responders subsequently showed progression after 6.2 and 9.9 months, the third has maintained PR at 7.7 months to date. Eight of 10 patients showed decrease in the sum of target lesion size (mean decrease of 16%; range -57 to 77%). One grade 2 event of ICI nephritis resolved with corticosteroid treatment. Conclusions: Three patients showed confirmed PR by RECIST 1.1 in Simon's stage 1, meeting criteria to proceed to Simon's stage 2. A total of 22 patients in the HNSCC will be enrolled. VV1 plus cemiplimab shows promise in first line R/M HNSCC based on these initial results. Clinical trial information: NCT04291105 . Patient demographics. N (treated) 10 Sex 20% female Median age (y) 60 (54 – 76) Oropharynx 7 HPV+ 7 Oral cavity 3 PD-L1 CPS median (range) 7.5 (1-45%) Locoregional injection 3 Distant injection 6 Local and distant injection 1 Best response (RECIST 1.1) PR 3 SD 5 PD 2 Adverse Events #pts any VV1/cemiplimab-related G3 AE 4 Lymphopenia 3 Elevated ALK 1

e16246 Background: First line systemic therapy for advanced hepatocellular carcinoma (HCC) includes immune checkpoint inhibitor (ICI) combination therapy, with tyrosine kinase inhibitors (TKIs), lenvatinib or cabozantinib, commonly used as second line therapy. However, there is limited data comparing efficacy of TKIs following first line ICI therapy. In the present study, we compared survival and risk of hospitalization in a propensity score matched analysis of patients who received lenvatinib or cabozantinib following progression on first line ICI therapy in patients with advanced HCC. Methods: We performed a retrospective cohort study using data from TriNetX, a healthcare database of over 150 million patients in the United States. We identified adult patients with a history of HCC who received atezolizumab plus bevacizumab (A+B) or durvalumab plus tremelimumab (D+T) as first line treatment. We then stratified patients by use of lenvatinib or cabozantinib in the subsequent line setting. Propensity score matching (PSM) was conducted between those who received lenvatinib and those who received cabozantinib, matching for demographic factors (age, sex, race), clinical characteristics (history of alcohol use, ascites, esophageal varices, or viral hepatitis), and laboratory parameters [platelets, albumin, bilirubin, INR and alpha-1-fetoprotein (AFP)]. Results: We identified 416 patients who were initially treated with either A+B or D+T, with 327 patients receiving A+B and 89 patients receiving D+T. Of these, 336 patients (80.8%) subsequently received lenvatinib and 80 patients (19.2%) received cabozantinib. Baseline characteristics of demographic factors, clinical characteristics, and laboratory parameters were comparable between patients in the lenvatinib arm and cabozantinib arm with all standardized mean differences (SMD) < 0.10. After PSM, 76 patients were included in the analyses, with all variables adequately balanced. There was no significant difference in the risk of hospitalization between those receiving lenvatinib or cabozantinib at 3 months [31.6% vs 34%, odds ratio (OR) 1.13, 95% confidence interval (CI) 0.57-2.2]. There was also no significant difference in mOS between those receiving lenvatinib and cabozantinib [9.5 vs 9.0 months, hazard ratio (HR) 1.03, 95% CI 0.62-1.7]. Conclusions: In patients with HCC who received lenvatinib or cabozantinib as second-line therapy following first-line ICI combination therapy, we found no significant differences in rate of hospitalization or survival. These findings suggest that either option may be appropriate, and decisions may be based in side effect profile and patient preferences. Prospective studies will be important to further assess differences in patient outcomes.

ABSTRACT Introduction Hairy cell leukemia (HCL) is an uncommon hematopoietic stem cell disease known to have an underlying somatic BRAF V600E driver mutation. Currently, the most accepted treatment is five or seven consecutive days of outpatient infusion of cladribine (e.g., continuous infusion), despite frequent antibiotic use and hospitalization with this regimen. As a result, a few investigators have adopted weekly infusion of cladribine with similar or improved results and fewer side effects. Methods We conducted a retrospective, single‐institution cohort study of 36 treatment‐naïve patients with HCL treated at the University of Colorado Hospital. Eighteen patients received intermittent weekly cladribine (intermittent cladribine [IC]) for 5–7 doses and 18 received standard daily cladribine (continuous cladribine [CC]) over 5–7 days. We report clinical cohort characteristics, response rates, progression‐free survival, overall survival, toxicity, hospitalization rates, and measurable residual disease monitoring in select patients using peripheral blood quantitative BRAF V600E PCR. Results We report here our experience with 18 patients with newly diagnosed BRAF ‐mutated HCL treated with weekly cladribine at a single institution compared to 18 HCL patients who received continuous infusions. Baseline hematologic parameters and overall survival were comparable between groups ( p = 0.1135), but there was a higher rate of complete remission for patients treated with IC (94.4% vs. 61.1%) with significantly improved progression‐free survival ( p < 0.0001). We observed comparable rates of neutropenia, neutropenic fever, antibiotic use, and G‐CSF administration. There were fewer hospitalizations for patients treated with IC (4/18) compared to patients treated with CC (6/18). Rituximab exposure differed between groups, with 72% of patients in the IC cohort receiving rituximab compared with 27.2% in the CC cohort (although treatment status was documented for only 66.7% of patients in the CC cohort). Peripheral blood BRAF V600E allele burden significantly declined and correlated with clinical remission, but this was only performed in select patients who were treated in recent years. Conclusions In this retrospective analysis, IC dosed weekly was associated with improved progression‐free survival and higher rates of complete remission compared to CC with comparable toxicity and fewer hospitalizations. These findings suggest a potential clinical benefit from this regimen. However, interpretation of these findings is limited by the non‐randomized design and differences in rituximab exposure between groups, which may have contributed to the observed outcomes and limited definitive conclusions. Trial Registration: The authors have confirmed clinical trial registration is not needed for this submission

ABSTRACT Introduction Community health workers (CHWs) help patients navigate community resources. CHW programs can improve health outcomes and reduce healthcare utilization, but identifying eligible patients is challenging. We developed an electronic health record (EHR)‐based algorithm trained to predict referrals to a CHW program. Our objective was to evaluate whether an algorithm trained on historical referrals identifies a subgroup of patients that differs from the subgroup identified through questionnaire‐based health‐related social needs (HRSN) screening alone. Methods This analysis used data from Mayo Clinic primary care patients in Southeast Minnesota. We developed a gradient boosted time‐to‐event model that incorporated demographics, diagnoses, HRSN questionnaire responses, and HRSNs derived from clinical notes using natural language processing. We compared the characteristics of algorithm‐identified patients with those identified through questionnaires and assessed the variable importance of model features. Results The algorithm had AUC: 0.87 in the training and 0.92 in the hold out set. Patients flagged by the algorithm tended to use interpreter services more commonly (12.6% vs. 1.3%), have a non‐English preferred language (14.1% vs. 2.3%), and have more instances of health literacy documented (5.36 vs. 1.29) compared to patients identified by the HRSN questionnaire. Only 47.0% of patients flagged by the algorithm had responded to the HRSN questionnaire within 2 years. Variable importance was highest for health literacy and financial strain from unstructured notes. Conclusions The algorithm is a chart‐review prioritization tool for referral to the CHW program for patients that may overcome challenges to identifying patients with HRSNs, especially when questionnaire data is incomplete.

e12601 Background: Mammography remains the standard modality for breast cancer (BC) screening but has several limitations. There is a critical need for minimally invasive markers that can aid in distinguishing benign, non-invasive lesions from those likely to progress to invasive BC. Platelets are nature’s transport mechanism for delivery of growth factors and inhibitors. Assaying the platelet proteome, Hessian Labs developed HeLP (Hessian Labs Personalized) test designed to identify early malignancy, as well as its grade, and invasiveness. The test is based on a discovery that platelets sequester oncogenic regulators against a concentration gradient in plasma early in tumor development. Hence, it has the potential to differentiate benign from invasive BC at various stages, stratifying the need for intervention. Methods: Platelet samples from 120 women with BC were analyzed using a discovery data-independent acquisition mass spectrometry (DIA-MS). The identified differentially expressed platelet-associated proteins, were prioritized using ClariaIQ , a proprietary computational platform that ranks proteins based on their relevance to stage-specific oncogenic pathways and established Cancer Hallmarks, to identify stage- and grade-associated proteomic signatures and create the HeLP panel. Results: DIA-MS identified multiple platelet sequestered proteins that were differentially expressed between indolent disease and invasive BC. ClariaIQ prioritization resulted in the selection of 13 proteins for inclusion in the HeLP breast cancer assay. We present two examples: SAA1 and SERPIN proteins demonstrated differential expression between healthy, benign breast lesions and malignant invasive disease (Table 1). SAA1 peaks in early BC and SERPIN in advanced stages. With SAA1, in HER negative BC the levels rise to an average of 285,000 RE units when compared to HER2 positive BC. Conclusions: Platelet sequestered protein signatures provide clinically relevant information regarding breast cancer status, grade, and invasiveness. The findings support the robustness of the signal, and a more patient-specific signature than traditional plasma or serum biomarkers. It suggests a role for HeLP as a minimally invasive adjunct to mammography to improve diagnostic stratification and therapeutic decision-making. Disease Group SAA1 Mean (RE) SAA1 SD (RE) SERPIN A3 Mean (RE) SERPIN A3 SD (RE) Healthy Controls 119,592 206,349 490,231 279,017 Benign Breast Lesions 622,187 50,855 341,102 153,144 Stage I Breast Cancer 1,223,865 1,878,654 742,409 466,468 Stage II Breast Cancer 663,369 1,970,265 922,381 844,512 Stage III Breast Cancer 437,853 662,211 705,994 597,399 Stage IV Breast Cancer 225,265 384,826 1,068,874 1,415,934 RE=Relative Expression units. N=20 subjects included in each group.

7094 Background: Waldenström Macroglobulinemia (WM) remains incurable with current available therapeutic options. Treatment options for relapsed/refractory pts are limited and often continuous, underscoring the need for new agents with novel mechanisms of action and pt-centered, fixed duration therapy. Iopofosine I 131 is a novel radiopharmaceutical compound composed of a lipid raft-targeting phospholipid ether covalently bound to 131 I, a beta emitting radioisotope. Here, we report preliminary sub-group results of the CLOVER-WaM study [NCT02952508] in WM pts treated with a Bruton’s Tyrosine Kinase inhibitor (BTKi) immediately prior to iopofosine. Methods: Eligible WM pts had received >2 prior therapies and had symptomatic disease requiring therapy according to consensus recommendations for WM. Treatment consisted of 2 cycles of iopofosine I 131 administered at 15 mCi/m 2 on days 1 and 15 of each 57-day cycle. The primary efficacy endpoint was major response rate (MRR; partial response or better, as determined by the modified IWWM-VI). Secondary and exploratory endpoints included overall response rate (ORR), treatment-free survival (TFS), progression free survival (PFS), duration of response (DOR), and clinical benefit rate (CBR; stable disease or better). Herein, efficacy endpoints were assessed in the modified intent-to-treat (mITT) population (all pts who received ≥60 mCi total administered dose of iopofosine I 131), and whose treatment regimen prior to iopofosine included a BTKi. Safety was evaluated using CTCAE v4.03 in pts who received ≥1 dose of iopofosine. Data cut off for this analysis was Jan. 16, 2026. Results: As previously reported, 65 pts were dosed and 55 are included in the mITT population. Of those, 22 (40%) had received a BTKi containing regimen immediately prior to iopofosine; and 11 who previously received at least 2 regimens utilizing BTKis and 12 who were refractory to rituximab. In this subgroup, median age was 70.5 (range 55-88), 17 (77%) were male, and 5 (23%) were female. The median number of prior therapies was 3 (range 2-7), 15/22 (68%) were MYD88 mutated and 18/22 (82%) were TP53 wildtype. The MRR was 15/22 (68.2%), ORR was 19/22 (86.4%) and CBR was 100%, median PFS was 12 months (range 1.6 to 28.0) and median TFS was 19.1 months (range 2.5-34.4). Grade ≥ 3, related treatment emergent adverse events (TEAE) occurring in > 10% of pts included anemia (41%), leukopenia (41%), neutropenia (58%), and thrombocytopenia (86%). Conclusions: Iopofosine I 131 demonstrated significant efficacy; 100% CBR, 86.4% ORR and 68.2% MRR with a median PFS of 12 months (range: 1.6 – 28.0 months) in a pt population with no current standard of care therapy. The treatment was well-tolerated with a manageable toxicity profile with cytopenias as the only Grade 3 or greater TEAE. Based on the results of this pivotal trial, iopofosine I 131 could be a promising novel treatment for WM pts after BTKi therapy. Clinical trial information: NCT02952508 .

4178 Background: In the CABINET trial, CABO significantly prolonged progression-free survival (PFS) compared to placebo (PB) in patients (pts) with advanced, previously treated extrapancreatic NET (epNET) or pancreatic NET (pNET) (Chan et al., NEJM, 2025). Here we report outcomes according to functional status based on NET hormone secretion. Methods: Pts with locally advanced or metastatic epNET or pNET were randomized 2:1 in separate cohorts to receive CABO 60 mg daily vs PB. Eligibility included progression by RECIST within 12 months (mo) before registration, ≥ 1 prior systemic therapy not including somatostatin analogs (SSA). Pts with functional NET due to hormone secretion and non-functional NET were included. In this post hoc subgroup analysis, we analyzed PFS by blinded independent central review and adverse events for pts receiving CABO vs PB based on functional status. Cox regression models were used with stratification on primary tumor site (epNET vs pNET). Subset analyses to evaluate treatment arm differences were conducted in pts with functional and non-functional tumors. Due to small numbers, separate results for those with unknown functional status are not included. Results: Of the total 298 pts enrolled in both cohorts, 74 had a functional NET (CABO, n = 47; PB, n = 27); 179 had a non-functional NET (CABO, n = 123; PB, n = 56); 45 had unknown functional status (CABO, n = 28; PB, n = 17). For functional NET, primary tumor sites were GI tract (n = 50; 68%), pancreas (n = 15; 20%), unknown (n = 4; 5%), lung (n = 3; 4%), and thymus (n = 2; 3%). Secreted hormones that were reported included serotonin (55%), somatostatin (18%), gastrin (16%), glucagon (4%), insulin (4%), ACTH (1%), and vasoactive intestinal peptide (1%). For non-functional NET, primary tumor sites were pancreas (n = 75; 42%), GI tract (n = 42; 23%), lung (n = 30; 17%), unknown (n = 17; 9%), thymus (n = 8; 4%), and other (n = 7; 4%). Concurrent SSA was received by 91% and 53% of pts with functional and non-functional NET, respectively. In both subgroups, CABO was associated with improved PFS compared to PB (for functional NET: stratified hazard ratio [sHR], 0.40; 95% confidence interval [CI]: 0.20-0.82, P = 0.012; for non-functional NET: sHR, 0.26; 95% CI: 0.17-0.41, P < 0.001). The most frequent grade 3/4 adverse events (AEs) attributed to CABO vs PB in pts with functional NET included hypertension (21% vs 11%), diarrhea (9% vs 11%), and fatigue (2% vs 15%); in pts with non-functional NET, grade 3/4 AEs included hypertension (21% vs 4%) and fatigue (18% vs 4%). Conclusions: Subset analyses of the CABINET trial suggest that CABO is an effective treatment option for pts with functional and non-functional epNET or pNET. Efficacy and safety results for pts with functional or non-functional NET treated with CABO are consistent with results for the entire trial. Clinical trial information: NCT03375320 .

4163 Background: Standard first-line systemic therapy for hepatocellular carcinoma involves immune checkpoint inhibitors, including A+B and the STRIDE regimen consisting of D+T. However, there is limited data comparing outcomes of patients receiving these two regimens. We aimed to compare the survival and safety profiles of patients receiving A+B versus D+T as first-line systemic therapy for advanced HCC in a propensity score matched analysis. Methods: We performed a retrospective cohort study using data from TriNetX, a healthcare database of over 150 million patients in the United States. We identified adult patients with a history of HCC and included those who received A+B or D+T as first line treatment. Propensity score matching (PSM) was conducted, matching for patient demographics (age, sex, race), clinical history (alcohol use, ascites, esophageal varices, viral hepatitis), and laboratory parameters [platelets, albumin, bilirubin, INR, alpha-1-fetoprotein (AFP)]. Median overall survival (mOS) and relevant patient safety events were compared between those who received A+B or D+T. Results: We identified 2,762 patients who had HCC who were treated with A+B or D+T, of which 2,030 patients received A+B and 723 patients received D+T. Compared to patients in the A+B cohort, those who received D+T were more often older (68.5 vs 66.9 years, standardized mean difference (SMD) = 0.17), had lower platelet counts (186.4 vs 198.6, SMD = 0.11), had higher prevalence of ascites (33.1% vs 20.3%, SMD = 0.29), and alcohol use (23.8% vs 18.8%, SMD = 0.12). After PSM, 723 patients were included in survival analyses, with all variables adequately balanced except for albumin, which was higher in the A+B group (3.6 vs 3.5, SMD = 0.19). At 90 days after starting therapy, D+T was associated with higher incidence of immune-mediated colitis [5.3% vs 2.6%, odds ratio (OR) 2.1; 95% confidence interval (CI), 1.2-3.7], and a higher risk of hospitalization [35.4% vs 27.9%, OR 1.4; 95% CI, 1.1-1.8]. At 6 months, the risk of hypertension and proteinuria was higher in the A+B cohort [21.9% vs 13.7%, OR 0.57; 95% CI, 0.34-0.95], which persisted at 1 year [28.1% vs 16.5%, OR 0.51; 95% CI, 0.32-0.81]. There was no significant difference in mOS between those receiving A+B or D+T [18.3 months vs 22.8 months, hazard ratio (HR) 0.94; 95% CI, 0.79-1.1]. Conclusions: In patients with advanced HCC who received A+B or D+T as first-line systemic therapy, we found that A+B was associated with higher risk of hypertension and proteinuria, while D+T was associated with a higher risk of immune-mediated colitis and hospitalization. No significant difference in mOS was observed between the cohorts. These findings suggest that safety profiles, rather than survival differences, may be used to guide optimal first-line treatment regimens. Prospective studies are warranted to further assess differences in patient outcomes.