The adenosinergic pathway represents a critical immunometabolic checkpoint within the tumor microenvironment of non-small cell lung cancer (NSCLC), contributing to immune suppression and therapeutic resistance. PBF-1129, an oral, selective A2B adenosine receptor (A2BAR) antagonist, was evaluated in a phase 1, open-label, dose-escalation trial (NCT03274479) in patients with advanced/metastatic NSCLC who had progressed on standard therapies. All patients had previously received chemotherapy and immune checkpoint blockade. Twenty-one patients received escalating doses (40–320 mg once daily), with no dose-limiting toxicities observed. The most frequently reported treatment related adverse events of any grade were lymphocytopenia (n = 8, 38.1

Water plot of best response in lung NEN.

Evaluation of circulating CD8+ cell subsets. (A) Changes in levels of circulating CD8+ naïve (CD45RA+ CCR7+), central memory (CM; CD45RA- CCR7+), effector memory (EM; CD45RA- CCR7-), and terminal effector memory (TE; CD45RA+ CCR7-) subsets at screening and cycle 1, day 15 (C1D15) of nivolumab and temozolomide treatment in the entire study cohort. (B) Levels of co-inhibitory molecules PD-1, LAG3, TIM3, and KLRG1 on circulating CD8+ T cells on study treatment compared to screening. Each symbol represents one patient (n = 9). Line indicates mean, *p<0.05

Evaluation of circulating MDSC. (A) Changes in total MDSC and (B) monocytic (M-MDSC) and granulocytic (G-MDSC) subsets at cycle 1, day 15 (C1D15) compared to screening in the entire patient cohort. (C) Levels of circulating MDSC at screening by clinical response and changes during study treatment compared to screening in partial response (PR, orange) and stable disease (SD, green) patients. Each symbol represents one patient (n = 9). Line indicates mean.

Evaluation of circulating CD4+ T cell subsets. (A) Changes in regulatory T cells (Tregs) during treatment compared to screening in the entire patient cohort. (B) Changes in levels of circulating CD4+ naïve (CD45RA+ CCR7+), central memory (CM; CD45RA- CCR7+), effector memory (EM; CD45RA- CCR7-), and terminal effector memory (TE; CD45RA+ CCR7-) subsets at screening and cycle 1, day 15 (C1D15) of nivolumab and temozolomide treatment in the entire study cohort. (C) Levels of co-inhibitory molecules PD-1, LAG3, TIM3, and KLRG1 on circulating CD4+ T cells on study treatment compared to screening. Each symbol represents one patient (n = 9). Line indicates mean, *p<0.05.

Supplementary Table 1: Most common treatment related adverse events; Supplementary Table 2: Treatment related serious adverse events; Supplementary Table 3: Mass Cytometry (CyTOF) panel; Supplementary Table 4: Mass cytometry gating of immune cell populations; Supplementary Table 5. Representativeness of Study Participants.

Pyrimidine biosynthesis, as a precursor of RNA and DNA, is essential for cell proliferation. Targeting pyrimidine metabolism with chemotherapy has been a treatment backbone for many cancers. Dihydroorotate dehydrogenase (DHODH) is an enzyme that is critical for de novo pyrimidine biosynthesis. Our team designed and synthesized an orally bioavailable small-molecule DHODH inhibitor, JBZ-001 (HOSU-53), as a candidate with good drug-like properties and oral bioavailability in mice and rats. In vivo testing of JBZ-001 established efficacy in multiple mouse xenograft models: small-cell lung cancer (NCI-H82 xenograft, tumor growth inhibition, TGI = 84%), colorectal cancer (HCT-15 xenograft, TGI = 91%), lymphoma (Z-138 xenograft, TGI = 102%), gastric cancer (SNU-16 xenograft, TGI = 88%), and melanoma (A375 xenograft, TGI = 64%) (Bennett C, ACS 2024). It showed superior preclinical efficacy when compared with other clinical candidates. It also showed a favorable toxicity profile with no observed adverse effects levels identified in the preclinical toxicity studies in rats and dogs. JBZ-001 has been moved to phase 1 testing in humans. The JBZ-001- phase 1 study will characterize the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary antitumor activity of JBZ-001 as a single agent in patients with advanced solid tumors and non-Hodgkin lymphoma (NHL). Dose escalation will identify the optimal biological dose (Part 1), and the dose expansion (Part 2). We will test preliminary activity in cohorts of up to 10 patients with the same tumor type. A Bayesian safety monitoring rule will be used to evaluate the rate of dose-limiting toxicities (DLTs). Eligible patients are adults ≥18 years of age with confirmed relapsed or refractory advanced solid tumors and NHL, for which no standard approved treatment is available; have measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1; and an ECOG performance status of 0-2. The primary endpoint is determination of the optimal dose by assessment of specific DLTs and adverse events per Common Terminology Criteria for Adverse Events (CTCAE) v.5. Secondary endpoints include PK and PD parameters, objective response rate per RECIST v1.1, and duration of response. Safety and antitumor activity endpoints will be summarized using descriptive statistics. Recruitment is ongoing for Part 1 at The Ohio State University Comprehensive Cancer Center (WCG IRB 20245148). Asrar Alahmadi, Chad Bennett, Sebastian Biglione, Zuzana, Jirakova, Carly JR Pilcher, Ridge Archer, Tamara Jovonovich, Dwight Owen, Christian Rolfo, Robert Wesolowski, Claire Verschraegen, David Carbone. An open-label phase 1 study to investigate JBZ001 in adults with advanced solid tumors and non-Hodjkin lymphoma (JBZ001, trial in progress) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_2):Abstract nr CT199.

Evaluation of co-inhibitory molecules by patient response. Total T cells at screening and C1D15 were identified as being CD4+ or CD8+ and patients were grouped by best clinical response as partial response (PR) or non-PR. The percentage of each T cell subset expressing (A) PD-1, (B) LAG3, (C) TIM3, and (D) KLRG3 at screening and C1D15 are shown. * p < 0.05.

TPS2090 Background: Patients with non-small cell lung cancer (NSCLC) with ALK rearrangements have a high frequency of brain metastases. Alectinib was shown to be superior to crizotinib in the first-line treatment of patients with ALK-positive NSCLC in the ALEX trial, and the intracranial response rate (CNS ORR) was 85.7% with alectinib versus 71.4% with crizotinib in patients who received prior radiotherapy and 78.6% versus 40.0%, respectively, in those who had not. Alectinib has also shown benefit in earlier stages of NSCLC. Given the high intracranial efficacy rate demonstrated by alectinib, as well as the known toxicities of cranial irradiation, the role of early irradiation of CNS disease vs delaying radiation in favor of treatment with alectinib needs to be defined to inform clinical practice. Methods: NCT05987644 is a multi-center, multi-cohort study consisting of a Phase 1b and Phase 2 portion. The Phase 1b portion of the study is a single-arm, open label study of alectinib in patients with CNS disease. Twelve subjects will be enrolled in the Phase 1b portion of the study and treated with alectinib alone; patients with PD will come off study treatment and move on to standard of care treatment per national guidelines. The phase 2 portion will be a randomized, non-blinded, open-label study. Forty-four subjects will be enrolled and randomized 1:1 to either alectinib upfront (Arm A) or alectinib + SRS (arm B). A group sequential design will be implemented with one interim analysis for futility and, and one final analysis using the composite outcome. The primary objective of phase 1b is to determine the safety and feasibility of delayed brain radiation in patients with ALK fusion positive NSCLC and CNS metastases. The primary objective of the phase 2 study is to determine whether treatment with alectinib results in preserved neurological status and control of CNS disease at 12 months compared to alectinib plus SRS. Secondary endpoint will be intracranial progression free survival at 12 months (icPFS12), response rate and icPFS, OS, and safety and tolerability. The study is open and accruing at 4 sites. Clinical trial information: NCT05987644 .

Few viable treatment options are available for relapsed extensive-stage small cell lung cancer (ES-SCLC). We previously presented clinical outcomes from a phase 2 trial evaluating the efficacy of nivolumab and temozolomide (TEM) in patients with ES-SCLC (NCT03728361). Here, we report pre-planned exploratory analyses exploring the association of circulating tumor DNA (ctDNA) changes with clinical outcomes.

Immune-checkpoint inhibitors (ICI) combined with chemotherapy is an FDA approved and standard approach for treating non-small cell lung cancer (NSCLC). Immune-related adverse events (irAEs) are a unique set of toxicities that occur with ICI and have been shown to be correlated with increased overall survival (OS). Most studies conducted to date have focused only on ICI without chemotherapy. In this study, 217 NSCLC patients treated first-line with either ICI alone or in combination with chemotherapy (ICI-Chemo) were evaluated to investigate differences in incidence, risk factors, effect on OS, or timing of irAEs between treatment groups.

AbstractPurpose:Treatment options are limited in patients with metastatic neuroendocrine neoplasms (NEN). We present the results for a phase II trial of combination nivolumab and temozolomide in patients with advanced NEN along with results of immune changes in peripheral blood.Patients and Methods:NCT03728361 is a nonrandomized, phase II study of nivolumab and temozolomide in patients with NEN. The primary endpoint was response rate using RECIST 1.1. Secondary endpoints included progression-free survival (PFS), overall survival (OS), and safety. Immune profiling was performed by mass cytometry to evaluate the effect on peripheral blood immune cell subsets.Results:Among all 28 patients with NEN, the confirmed response rate was 9/28 [32.1%, 95% confidence interval (CI): 15.9–52.4]. Of 11 patients with lung NEN, the response rate was 64% (n = 7); there was a significant difference in responses by primary tumor location (lung vs. others, P = 0.020). The median PFS was 8.8 months (95% CI: 3.9–11.1 months), and median OS was 32.3 months (95% CI: 20.7—not reached months). Exploratory blood immune cell profiling revealed an increase in circulating CD8+ T cells (27.9% ± 13.4% vs. 31.7% ± 14.6%, P = 0.03) and a decrease in CD4+ T cells (59.6% ± 13.1% vs. 56.5% ± 13.0%, P = 0.001) after 2 weeks of treatment. LAG-3–expressing total T cells were lower in patients experiencing a partial response (0.18% ± 0.24% vs. 0.83% ± 0.55%, P = 0.028). Myeloid-derived suppressor cell levels increased during the study and did not correlate with response.Conclusions:Combination nivolumab and temozolomide demonstrated promising activity in NEN.See related commentary by Velez and Garon, p. 691

4121 Background: Treatment options are limited in patients with metastatic NEN. Temozolomide (TEM) alone and in combination with capecitabine is active in NEN and has been shown to have immunomodulatory impact. Here we present the final results for the NEN cohort of a phase 2 trial of combination nivolumab and TEM in patients with advanced NEN along with observed peripheral immune changes. Methods: NCT03728361 is a non-randomized, two-cohort, open-label phase 2 trial of nivolumab and TEM in patients with metastatic NEN and small cell lung cancer. The NEN cohort enrolled patients with tumors of any WHO grade, location, and line of therapy; all patients had evidence of progression prior to study. Prior immunotherapy was not allowed. Treatment consisted of nivolumab 480 mg IV on day 1 and TEM 150 mg/m2 on days 1-5 of a 28-day cycle. The primary objective was efficacy measured as response rate (RR) by RECIST v1.1. Secondary objectives were progression free survival (PFS) and overall survival (OS), by the method of Kaplan–Meier. The translational objective was to analyze peripheral blood mononuclear cells (PBMCs) collected at screening (baseline) and on cycle 1, day 15 (C1D15) via mass cytometry. Results: The RR was 36% (n=10/28, 95% CI: 18.6%-55.9%), including 10 patients (36%) with PR, 16 (57%) with SD, and 2 (7%) with PD (Table). The disease control rate was 93%. Responses occurred across all WHO grades; 44% of patients with tumors with Ki-67 >20% had PR. There was a significant difference in ORR by primary tumor location (bronchial vs pancreas vs other, p=0.004). There was no significant difference in response by Ki-67% (p=0.872), or in patients treated as first line (31%) or beyond (40%, p=0.706). The median PFS was 8.9 months (95% CI: 3.9 – 11.1 months), and median OS was not reached (95% CI: 20.7 – NR months). Two immune related SAE’s occurred: myocarditis and diarrhea in one patient each; gr4 toxicities included neutropenia (10%) and thrombocytopenia (7%). Profiling of PBMCs revealed no correlation of baseline MDSC levels with clinical benefit, however significant changes within the T cell landscape, including a decrease in CD4+ T cells (59.6% ±13.08 vs. 56.5% ±13.01, p=0.001) and increase in CD8+ T cells (27.9% ±13.36 vs. 31.7% ±14.57, p=0.03) were observed. Conclusions: Combination nivolumab and TEM demonstrated promising efficacy in patients with NENs; median OS has not been reached. Clinical trial information: NCT03728361. [Table: see text]

Treatment options are limited for patients with extensive stage small cell lung cancer (ES-SCLC) after progression on first line chemo-immunotherapy (CIT). Temozolomide (TEM) is active in ES-SCLC and has been shown to have an immunomodulatory effect for patients with advanced cancers. Immune checkpoint inhibitor (ICI) therapy combined with TEM has demonstrated promising activity among patients in 2nd and 3rd line after CIT (NCT03728361, reported at this meeting). Two different dosing regimens of TEM monotherapy have been explored in ES-SCLC but the objective response rate among patients treated after first line CIT remains unknown.

4123 Background: LAG-3 is an immune checkpoint present on NK cells, activated T cells and myeloid cells that inhibit T cell responses. Recent evidence demonstrating the safety and efficacy of LAG-3 inhibition has increased interest in this pathway for the treatment of multiple malignancies but the role in NEN is unclear. We present results from correlative peripheral blood mass cytometry (CyTOF) performed in a phase 2 trial (NCT03728361) of the combination of NIVO and TMZ in pts with advanced NEN. Methods: Patients (pts) with progressive NEN of any grade or primary location and any line of therapy were eligible. Small cell lung cancer was excluded. Clinical results from NCT03728361 will be presented in a separate abstract. Study treatment consisted of NIVO 480 mg IV every 4 weeks and TMZ 150 mg/m2 for 5 consecutive days out of a 28-day cycle. Peripheral blood mononuclear cells (PBMCs) were available from 16 out of 28 patients at screening (baseline) and cycle 1, day 15 (C1D15) and analyzed via CyTOF. Antibody labelling was performed using a 37 marker Maxpar Direct Immune Profiling Assay (Fluidigm). Immune cell populations were compared using two sample t-tests between pts with partial response (PR) and non-partial response (non-PR). Results: At screening, no differences were observed in PD-1, TIM3, or KLRG1 positive T-cell populations between pts with PR or non-PR. Patients with a PR had a significantly lower % of LAG-3 expressing T cells (p=0.029). There was a trend towards a lower % CD8+LAG-3+ T cells in pts with PR (p=0.086). At C1D15: The % of CD8+ LAG-3+ T cells were significantly higher in PRs vs. non-PR (p = 0.015). In matched samples comparing T cell populations at screening to C1D15, LAG-3+ CD8+ T cells increased significantly in PRs when compared to non-PRs (p=0.021). Conclusions: The % of LAG-3+ T cell population at baseline associates with non-response to TMZ/NIVO in NENs. Among responders, there was a significant increase in CD8+ LAG-3+ T cells by Day 15 compared to baseline indicating a potential mechanism of immune escape and eventual resistance. Clinical trial information: NCT03728361. [Table: see text]

Treatment options are limited in patients with extensive stage small cell lung cancer (ES-SCLC) after progression on first line chemo-immunotherapy (CIT). Temozolomide (TEM) is active in ES-SCLC and has been shown to have immunomodulatory impact in patients with advanced cancers, however data are unavailable in patients after CIT. We present the final analysis of a phase 2 trial of combination nivolumab and TEM in patients with ES-SCLC as 2nd or 3rd line after progression on CIT.

•Platinum-resistant small-cell lung cancer (SCLC) is characterized by low response rates and short survival. •This case demonstrates sustained response to nivolumab and temozolomide as part of a clinical trial in platinum-resistant SCLC. •Clinical response was accompanied by a decrease in immunosuppressive myeloid-derived suppressor cells, which may be an early biomarker of response to treatment.