Luo, Jingqin

Abstract Purpose: Standard care for high-grade gliomas (HGG) involves maximal surgical resection followed by radiation and temozolomide. Postoperative adjuvant therapy frequently causes lymphopenia, which is associated with poor prognosis. Interleukin 7 (IL7) is essential for lymphocyte development, homeostasis, and survival. NT-I7 (efineptakin alfa), a long-acting recombinant IL7, reverses lymphopenia and improves survival in murine glioma models. However, the safety, maximum tolerated dose (MTD), and impact of NT-I7 on immune cells in patients with HGG remain unknown. Patients and Methods: We conducted a phase I trial (NCT03687957) examining the MTD and effect of NT-I7 on lymphocytes in patients with newly diagnosed HGG. The primary endpoint was dose-limiting toxicity; secondary endpoints included absolute lymphocyte count (ALC) changes over time, overall response, progression-free survival, and overall survival. Exploratory endpoints included immune profiling at different time points using single-cell RNA sequencing (scRNA-seq) in a subset of patients. Results: NT-I7 was well tolerated with a MTD of 720 µg/kg. Moreover, NT-I7 significantly increased ALCs for more than 12 weeks in duration. Early elevations in CD4+, CD8+ T cells and NK cells further coincided with increased TNF and CXCL9 cytokine levels. Comprehensive immune profiling of peripheral blood T cells revealed selective clonotype expansion within CD8+, but not CD4+, T cells following NT-I7 administration. Finally, a subset of our patients with MGMT promoter–unmethylated glioblastoma, which are typically associated with a poorer prognosis, demonstrated promising clinical responses. Conclusions: NT-I7 has the potential to maintain and increase lymphocyte counts in patients with HGG and warrants further investigation, particularly in combination with immune-based therapies.

Glioblastoma (GBM) is an aggressive brain tumor that often progresses despite resection and treatment. Timely and continuous assessment of GBM progression is critical to expedite secondary surgery or enrollment in clinical trials. However, current progression detection requires costly and specialized MRI examinations, which, in the absence of new symptoms or signs, are usually scheduled every 2–3 months. Here, we hypothesized that changes in daily activity are associated with GBM growth and disease progression. We found that wheel-running activity in GBM-bearing mice declined as tumors grew and preceded weight loss and circadian breakdown by over a week. Temozolomide treatment in the morning, but not evening, significantly reduced tumor size and restored daily locomotion in mice. In a pilot study of 6 patients with GBM wearing an actigraphy watch, wrist movement provided a feasible and continuous longitudinal indicator of daily activity with 1-minute resolution. After tumor resection and radiation, daily activity declined in 2 patients 19 and 55 days before detection of progression by MRI but did not change for the 4 patients with stable disease. These results suggest that daily activity tracking using wearable devices may serve as a real-time indicator and potential monitoring tool for GBM progression and treatment efficacy.

5069 Background: Ra-223 improves the overall survival in patients with mCRPC to the bone. We assessed the safety of standard-of-care Ra-223 in combination with peposertib, a DNA-dependent protein kinase inhibitor, with or without avelumab, an anti-PD-L1 antibody. Methods: Patients with mCRPC and two or more skeletal metastases identified by bone scintigraphy with or without lymph node metastases up to 3 cm in size, but no visceral metastases, were eligible. Progression after progression after at least one androgen receptor pathway inhibitor or taxane was required. Phase 1 consisted of a two-step sequential safety lead-in using a 3+3 design. Step 1 combined 6 standard cycles of Ra-223 (55 kBq/kg), with increasing doses of peposertib: 50, 100, and 200 mg PO bid on days 3-26 of each cycle. Step 2 combined Ra-223 with the maximum tolerated dose of peposertib and added standard avelumab 800 mg IV every 14 days, starting at cycle 2 of Ra-223. Results: A total of 9 patients participated in Step 1, where the maximum tolerated peposertib dose of 200 mg PO bid with Ra-223 was deemed tolerable. A total of 6 patients participated in Step 2 and the combination of Ra-223, peposertib at 200 mg PO bid, and standard avelumab was deemed tolerable. Of the 15 patients in Phase 1, none experienced grade 4 or higher treatment-related toxicities, while 7 experienced grade 3 toxicities, including neutropenia (1), anemia (1), cardiac chest pain (1), fall (1), maculopapular rash (2), and lymphopenia (2). The median (Q1, Q3) PSA velocity from the beginning to the end of treatment was lower for Step 2 versus Step 1: 2.1 (-0.1, 4.6) versus 23.5 (18.6, 77.1) ng/mL/month (p = 0.0067). OS and PFS were calculated with the limitation that the Phase 1 was non-randomized. Median OS was not reached for Step 2, as only 1 of 6 patients had died, versus 15.2 months for Step 1, where 8 out of 9 patients had died (p = 0.0537). The patient who died in Step 2 discontinued therapy prematurely after 3 cycles due to progression and survived 15.2 months (the 5 alive completed all 6 cycles). The median radiographic PFS was 7 months for Step 2 versus 12.7 months for Step 1 (p = 0.8910). Conclusions: The combination of Ra-223 and peposertib, with or without avelumab was well tolerated. The triplet combination showed the most promising results at this early evaluation. We continue to accrue in the randomized Phase II portion of the trial. Clinical trial information: NCT04071236 .

Abstract Lymphopenia following chemoradiation for high grade gliomas (HGG) is common and is associated with decreased survival. NT-I7 (efineptakin alfa) is a long-acting analog of the lymphocyte pro-survival cytokine, interleukin-7. Our Phase I dose-escalation study of 19 patients with HGG demonstrated early elevations in CD4+ and CD8+ T cells in the first 4 weeks after administration of NT-I7. In this study, we explored the diversity and potential functionality of the NT-I7-expanded T cell population. A subset of 4 subjects with glioblastoma multiforme (GBM) treated at 720 µg/kg of NT-I7 during adjuvant temozolomide in our study (NCT03687957) underwent Cellular Indexing of Transcriptomes and Epitopes by Sequencing (CITE-seq) of peripheral blood. CITE-seq with TCR clonotype sequencing (10x Genomics 5’) permitted simultaneous tracking of the T cell phenotype at the protein level, individual T cell clones, and gene expression dynamics between 4 timepoints: pre-treatment, and post-treatment weeks 1, 2, and 13. Here, we report the results of differential expression analyses between timepoints and patient-specific differences in T cell clonotype expansions. Both CD4+ and CD8+ T cells in our study patients had increased expression of T cell activation markers LTB, CISH, and CD74. CD8+ T cell subsets demonstrated additional elevations in genes important in cytotoxic function (granzymes (GZMA, GZMB) and perforin (PRF1)), MHC Class II expression (HLA-DRA, HLA-DRB1), and AP-1 transcription factor subunits (JUND, JUN, JUNB, FOS, FOSB). After excluding known viral antigen clonotypes, 2 of 4 patients demonstrated TCR clonotype expansion. Notably, nearly all the expanded TCR clonotypes were found within CD8+ T cells, but not CD4+ T cells. NT-I7 promotes activation, cytotoxic function, and selective clonotype expansion of CD8+ T cells in patients with HGG. This, combined with its role in increased CD4+ T cell counts, suggests NT-I7 may be a powerful tool to restore immune function after treatment-associated lymphopenia in HGG.

Abstract BACKGROUND Lymphopenia, a common finding in patients with high-grade gliomas (HGGs), is associated with poor outcomes including worse survival, fatigue, and in some cases, increased opportunistic infections. Interleukin-7 (IL-7) is a cytokine crucial for lymphocyte survival and proliferation. We previously demonstrated long-acting IL-7 (rhIL-7-hyFc, efineptakin alfa, NT-I7) increases absolute lymphocyte counts (ALCs) and extends survival in preclinical murine models of HGG. Here, we report results using rhIL-7-hyFc to effectively reduce lymphopenia in patients with HGG. METHODS We performed a phase II randomized, placebo-controlled, double-blind study of rhIL-7-hyFc in patients with newly diagnosed HGGs (82% IDH-wildtype glioblastoma in both groups). Patients received rhIL-7-hyFc (720mcg/kg) or placebo one-week post-radiation and temozolomide, with subsequent doses at weeks 13, 25, and 37. The primary endpoint was ALC four weeks post-initial administration; exploratory endpoints included CD4 count, progression-free survival (PFS), and overall survival (OS). RESULTS We enrolled 22 patients (median age 59.5 years, range 33-74; 40.9% female) with HGG. Both groups exhibited comparable demographics, including MGMT methylation status, and received a median of 2 doses of rhIL-7-hyFc or placebo. At 4 weeks, the pre-specified primary endpoint, ALC significantly increased relative to baseline in the treatment group, compared to placebo (median percent change=148% vs. 16.7%, p=0.007), as did CD4 count (121% vs. 10.5%, p=0.011). There were no treatment-related grade 4/5 adverse events. Exploratory endpoints of PFS and OS will be reported at time of conference. CONCLUSIONS rhIL-7-hyFc is safe and effective in improving ALC and CD4 count in patients with newly diagnosed HGG undergoing temozolomide and concurrent radiation therapy. This study was powered to meet the primary endpoint; larger trials will likely be required to demonstrate clinical efficacy. Nevertheless, these data support the continued exploration of rhIL-7-hyFc as an adjunct to standard therapy to mitigate lymphopenia and potentially extend survival for patients with HGG.

Abstract INTRODUCTION Immunotherapy has not improved survival in recurrent GBM (rGBM). Indoleamine 2,3 dioxygenase 1 (IDO1), highly expressed in ~90% of patients with malignant glioma, is a rate-limiting enzyme that catabolizes tryptophan (Trp) into kynurenine (Kyn) and enables immune escape. METHODS We hypothesized combining therapies targeting immunosuppressive pathways with cytotoxic and antiangiogenic therapies would overcome tumor-related immunosuppression. This was an open-label Phase II study of two regimens: Arm A consisted of retifanlimab (anti-PD1, 500mg IV Q4W) + bevacizumab (10mg/kg IV Q2W) + HFRT (3.5Gy/day x 10) in patients with IDH1/2-WT rGBM. Regimen B added the IDO inhibitor, epacadostat (400mg po BID), initiated prior to HFRT. Key inclusion criteria included dexamethasone ≤ 4 mg/day. The primary endpoint was overall survival (OS) at 9 months (OS-9). 24 evaluable patients were required to detect an OS-9 of 60% with 80% power, compared to 38% in historical controls (bevacizumab alone) by 1-sided 1-sample log rank test at alpha=0.1. RESULTS We previously reported Arm A. Here, we present results from Arm B. 25 of the 27 patients enrolled to regimen B were evaluable: median age 58years (23-71); 28% female; 23% MGMT promotor methylated; median KPS 90 (70 - 100); a median of 6 cycles of epacadostat as of May 2024 (1 - 13). 18 of 25 died with a median follow up 9.23 months. Median PFS was 7.52 months (95%CI: 5.52-9.43). Median OS was 9.5 months (95%CI 8.08-11.96). Regimen B met its primary endpoint with OS-9 of 61.07% (95%CI: 38.23-77.65%). There were 5 possible immune-related grade 3+ toxicities to date (2 ALT/AST increase; 3 rash). CONCLUSIONS Retifanlimab, epacadostat, HFRT, and bevacizumab in rGBM is well-tolerated, with encouraging OS and PFS at the time of submission. Arm B met its primary endpoint. Further studies are warranted to identify biomarkers to predict long-term responders.

Abstract INTRODUCTION Immunotherapies targeting PD-1 in recurrent glioblastoma (rGBM) have shown limited activity. We hypothesize combining therapies targeting immunosuppressive pathways with cytotoxic and antiangiogenic therapies will improve survival. This nonrandomized, noncomparative Phase II study examines safety and efficacy of an anti-PD-1 monoclonal antibody (retifanlimab), hypofractionated radiotherapy (HFRT), and bevacizumab, with or without an IDO1 inhibitor (epacadostat), in patients with rGBM. METHODS This is an open-label Phase II study of two regimens. Regimen A examines retifanlimab (500mg IV Q4W) + bevacizumab (10mg/kg IV Q2W) + HFRT (3.5Gy/day x 10) in patients with IDH1/2-WT rGBM. Regimen B adds epacadostat. Key inclusions include dexamethasone ≤ 4 mg/day and reirradiation candidacy. The primary endpoint is overall survival (OS) probability at 9 months (OS-9). An increase of OS-9 from 38% (bevacizumab alone) to 60% was considered clinically relevant and required 24 efficacy evaluable patients. RESULTS Regimen A accrual is complete; interim results are as follows: 26 rGBM enrolled, with 24 evaluable [median age 64.2 years (42.1-81.8); 29% female; 29% MGMT promotor methylated; 33.3% with multi-focal disease; median KPS 90 (70-100); median baseline dexamethasone 0 mg (0-4) and ALC 1,000 cells/µl (300-3,700)]. Patients received a median of 6 cycles as of May 2022 (2-24). Median follow-up is 16.0 months. Interim median PFS is 7.0 months (95%CI: 4.5~11.1) and median OS is 12.2 months (95%CI 7.1~18.0). Regimen A met primary endpoint with OS-9 of 67% (95%CI: 44~82%). Overall response rate is currently 58% (95%CI: 36.94~77.2%). There were five possible immune-related grade 3+ toxicities to date (n = 1 each colitis, vomiting, and seizure; n = 2 diarrhea). Regimen B is enrolling. CONCLUSIONS Interim analysis suggests combination retifanlimab, HFRT, and bevacizumab in rGBM is generally well-tolerated, with encouraging OS and PFS at the time of submission. Correlative analysis is ongoing and will be presented at the meeting.

AbstractThe temporal evolutions and relative orderings of Alzheimer disease biomarkers, including CSF amyloid-β42 (Aβ42), Aβ40, total tau (Tau) and phosphorylated tau181 (pTau181), standardized uptake value ratio (SUVR) from the molecular imaging of cerebral fibrillar amyloid-β with PET using the 11C-Pittsburgh Compound-B (PiB), MRI-based hippocampal volume and cortical thickness and cognition have been hypothesized but not yet fully tested with longitudinal data for all major biomarker modalities among cognitively normal individuals across the adult lifespan starting from 18 years. By leveraging a large harmonized database from 8 biomarker studies with longitudinal data from 2609 participants in cognition, 873 in MRI biomarkers, 519 in PET PiB imaging and 475 in CSF biomarkers for a median follow-up of 5–6 years, we estimated the longitudinal trajectories of all major Alzheimer disease biomarkers as functions of baseline age that spanned from 18 to 103 years, located the baseline age window at which the longitudinal rates of change accelerated and further examined possible modifying effects of apolipoprotein E (APOE) genotype. We observed that participants 18–45 years at baseline exhibited learning effects on cognition and unexpected directions of change on CSF and PiB biomarkers. The earliest acceleration of longitudinal change occurred for CSF Aβ42 and Aβ42/Aβ40 ratio (with an increase) and for Tau, and pTau181 (with a decrease) at the next baseline age interval of 45–50 years, followed by an accelerated increase for PiB SUVR at the baseline age of 50–55 years and an accelerated decrease for hippocampal volume at the baseline age of 55–60 years and finally by an accelerated decline for cortical thickness and cognition at the baseline age of 65–70 years. Another acceleration in the rate of change occurred at the baseline age of 65–70 years for Aβ42/Aβ40 ratio, Tau, pTau181, PiB SUVR and hippocampal volume. Accelerated declines in hippocampal volume and cognition continued after 70 years. For participants 18–45 years at baseline, significant increases in Aβ42 and Aβ42/Aβ40 ratio and decreases in PiB SUVR occurred in APOE ɛ4 non-carriers but not carriers. After age 45 years, APOE ɛ4 carriers had greater magnitudes than non-carriers in the rates of change for all CSF biomarkers, PiB SUVR and cognition. Our results characterize the temporal evolutions and relative orderings of Alzheimer disease biomarkers across the adult lifespan and the modification effect of APOE ɛ4. These findings may better inform the design of prevention trials on Alzheimer disease.

Abstract Glial fibrillary acidic protein (GFAP) is a promising candidate blood-based biomarker for Alzheimer’s disease (AD) diagnosis and prognostication. The timing of its disease-associated changes, its clinical correlates, and biofluid-type dependency will influence its clinical utility. We evaluated plasma, serum, and CSF GFAP in families with autosomal dominant AD (ADAD), leveraging the predictable age at symptom onset to determine changes by stage of disease. Plasma GFAP elevations appear a decade before expected symptom onset, after β-amyloid accumulation and prior to neurodegeneration and cognitive decline. Plasma GFAP distinguished β-amyloid-positive from β-amyloid-negative ADAD participants and showed a stronger relationship with β-amyloid load in asymptomatic than symptomatic ADAD. Higher plasma GFAP was associated with the degree and rate of neurodegeneration and cognitive impairment. Serum GFAP showed similar relationships, but these were less pronounced for CSF GFAP. Our findings support a role for plasma GFAP as a clinical biomarker for β-amyloid-associated cognitive deterioration in AD.

2058 Background: Immunotherapies targeting the programmed cell death-1 (PD-1) pathway in recurrent glioblastoma (rGBM) have failed. We hypothesize that combining therapies targeting multiple immunosuppressive pathways with cytotoxic and antiangiogenic therapies will improve survival. Here, we evaluate the safety and efficacy of an anti-PD-1 monoclonal antibody (retifanlimab), hypofractionated radiotherapy (HFRT), and bevacizumab, with or without an oral IDO1 inhibitor (epacadostat), in patients with rGBM in a nonrandomized, noncomparative sequential two-arm Phase II study. Methods: This is an open-label Phase II study of 2 sequential cohorts (Table). Cohort A first examines retifanlimab + bevacizumab + HFRT in patients with IDH1/2-WT rGBM. After a toxicity monitoring period, Cohort B, which adds epacadostat, starts enrolling. Key inclusion criteria includes dexamethasone ≤ 4 mg/day at registration and candidacy for reirradiation. Previous bevacizumab use for radiation necrosis is permitted. The primary endpoint is OS probability at 9 months (OS-9). Secondary endpoints include PFS, OS, and toxicity. Exploratory endpoints include immunological phenotyping of blood and tissue. An increase of OS-9 from 38% (bevacizumab alone) to 60% is considered clinically relevant. Results: From 6/2020 to 12/2021, we have completed accrual for cohort A and the interim analysis results are presented here: 25 patients with rGBM enrolled, with 23 evaluable. Median age is 64.3 years (42.1-81.8), 30.4% female, 30.4% MGMT promotor methylated, median KPS 90 (range 70-100), baseline dexamethasone 0 mg (range 0-4) with 52.2% of patients on dexamethasone during the first 3 cycles, median baseline ALC 1,000 cells/µl (range 300-3,700). Patients received a median of 6 cycles to date (range 2-20). Median follow-up is 11.97 months per the reverse Kaplan-Meier method. Interim analysis shows a median PFS of 9.9 months (95%CI: 5.5 to not reached (NR)) and median OS of 12.2 months (95%CI 7.3-NR). Notably, Cohort A met the primary endpoint with an OS-9 of 71.4% (95%CI: 46.7% -86.1%). No dose limiting toxicities have been yet observed. Two treatment-related grade 3 toxicities have occurred (myositis, hypertension). Cohort B enrollment is ongoing, and correlative studies pending. Conclusions: Interim analysis suggests retifanlimab combined with HFRT and bevacizumab in patients with rGBM is well-tolerated and had encouraging OS and PFS at the time of data cutoff. Cohort B, which adds epacadostat, is currently enrolling. Clinical trial information: NCT03532295. [Table: see text]