Carneiro, Benedito A.

Abstract Purpose: The safety, pharmacokinetics, and efficacy of elraglusib, a glycogen synthase kinase-3β (GSK-3β) small-molecule inhibitor, as monotherapy or combined with chemotherapy, in patients with relapsed or refractory solid tumors or hematologic malignancies was studied. Patients and Methods: Elraglusib (intravenously twice weekly in 3-week cycles) monotherapy dose escalation was followed by dose escalation with eight chemotherapy regimens (gemcitabine, doxorubicin, lomustine, carboplatin, irinotecan, gemcitabine/nab-paclitaxel, paclitaxel/carboplatin, and pemetrexed/carboplatin) in patients previously exposed to the same chemotherapy. Results: Patients received monotherapy (n = 67) or combination therapy (n = 171) elraglusib doses 1 to 15 mg/kg twice weekly. The initial recommended phase II dose (RP2D) of elraglusib was 15 mg/kg twice weekly and was defined, without dose-limiting toxicity observation, due to fluid volumes necessary for drug administration. The RP2D was subsequently reduced to 9.3 mg/kg once weekly to reduce elraglusib-associated central/peripheral vascular access catheter blockages. Other common elraglusib-related adverse events (AE) included transient visual changes and fatigue. Grade ≥3 treatment-emergent AEs occurred in 55.2% and 71.3% of patients on monotherapy and combination therapy, respectively. Part 1 monotherapy (n = 62) and part 2 combination (n = 138) patients were evaluable for response. In part 1, a patient with melanoma had a complete response, and a patient with acute T-cell leukemia/lymphoma had a partial response (PR). In part 2, seven PRs were observed, and the median progression-free survival and overall survival were 2.1 [95% confidence interval (CI), 2–2.6] and 6.9 (95% CI, 5.7–8.4) months, respectively. Conclusions: Elraglusib had a favorable toxicity profile as monotherapy and combined with chemotherapy and was associated with clinical benefit supporting further clinical evaluation in combination with chemotherapy.

SPOP mutations drive opposing molecular and immune landscapes in prostate and endometrial cancers, suggesting tailored therapies

Abstract Elraglusib is a selective GSK-3 inhibitor that has activity on a broad array of neoplasms as well as their immune microenvironment. However the determinants of tumor response have not been elucidated. Here, we use genomic panels of cancer driver genes to predict patient response to elraglusib therapy as measured by RECIST criteria. Patient response in the Phase I 1801 trial (NCT03678883) was matched to genomic data from patient tumors, with 80 cases used to train Machine Learning models and 26 cases reserved as a test set for model evaluation. When predicting response from mutation status alone our models reached a modest accuracy of 65% in the test set, which we attributed to the sparsity of genomic data. To remedy this, we engineered pathway-based features to provide combinatorial information while ensuring feature stability. To select the optimal combination of features, we designed an iterative design process that first randomized feature combinations and then created refined models from the highest performing pathway features. This resulted in several final models with greater than 88% accuracy. We retained several models of similar accuracy to more comprehensively identify potential biomarkers and combinatorial relationships. These models were then interpreted using SHapley Additive exPlanations (SHAP) where we were able to identify highly predictive features for both the entire pan-cancer cohort and specific histologies. We found the feature constructed from the Reactome pathway “Chromatin Modifying Enzymes” frequently occurred in high performing models with a high-ranking SHAP value. This feature included genes such as SMARCA4, HDAC2, and KDM5A, and was negatively associated with patient response. Another frequently observed high-ranking pathway feature with a negative response association was based on the “Innate Immune System” Reactome pathway. Many of the features highlighted in our models were negatively associated with elraglusib response and thus could be general markers of poor prognosis. To address this, we altered our pipeline to test only positively associated features which substantially reduced our feature pool to only 285 features but still produced models with accuracies of up to 81%. Analysis of key features used by these models identified several positive markers of elraglusib including mutations in the POLE gene, which previously has been linked to DNA-damage response deficiency and anti-tumor immune response. In sum, we forecast elraglusib response for a variety of tumor histologies and simultaneously reveal potential mechanisms of elraglusib sensitivity and biological action. In future work we will investigate the utility of using POLE and other identified biomarker candidates to predict the likelihood of patient response to elraglusib, as well as whether our machine learning models will be an effective tool to guide patient stratification. Citation Format: Joseph McDermott, Taylor Weiskittel, Daniel Billadeau, Benedito Carneiro, Hu Li, Andrew Mazar. Elraglusib response prediction and mechanistic discovery using iterative machine learning. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5355.

3079 Background: Elraglusib (9-ING-41), a novel inhibitor of GSK-3β, has been evaluated in >230 patients (pts) with advanced malignancies including metastatic melanoma in the 1801 phase 1/2 trial (NCT03678883). Pts with melanoma treated with single agent elraglusib demonstrated clinical benefit including a durable complete response despite multiple prior lines of therapy including checkpoint inhibitors (CPI). Methods: We collected data from numerous -omic modalities in the 1801 trial to characterize markers of elraglusib response with bioinformatics and machine learning (ML). Genomic panels were collected on 105 pts. The most frequent tumor types included colorectal cancer (n=35), pancreas (n=31), lung (n=15) and metastatic melanoma (n=12). Pts were treated with elraglusib as a single agent or in combination with chemotherapy. Pathway based features were generated by quantifying the percent of each Reactome pathway that was mutated. These pathway features were iteratively evaluated for their performance in shallow neural networks predicting patient RECIST with each model using 5-15 randomly selected features at a time. Publicly available genomic data from an anti-PD-1 trial in patients with metastatic melanoma (Hugo et al., 2017) was transformed into pathway-based features and input into the final model to predict elraglusib response in this population. Results: Our final pathway based genomic model for elraglusib response performed with a training accuracy of 93% and a test accuracy of 88% on the 1801 patients. We then tested the model on metastatic melanoma patients who were treated with anti-PD-1 therapy. We found that patients from Hugo et al. were predicted to respond to elraglusib (22/26). In addition, most patients with tumors resistant to anti-PD-1 therapy were also predicted to respond to elraglusib (10/12). Finally, we tested the model on metastatic melanoma patients treated with elraglusib in the 1801 study that had failed CPI and for whom -omic data was available. The model correctly identified 5/5 patients that demonstrated clinical benefit (1 CR, ongoing>1400 days; 4 prolonged OS of 107, 256, 357, and 556 days). Conclusions: We applied robust in-silico modeling developed using 1801 trial data to develop a rationale for the development of elraglusib in the treatment of metastatic melanoma including patients that failed or were refractory to anti-PD-1 treatment. This model correctly identified metastatic melanoma patients in 1801 with good clinical outcomes that had failed prior CPI treatment. Further, we present this in silico approach as a robust way to repurpose prior clinical study genomics and ML modeling for population enrichment during the clinical development of novel drugs. Clinical trial information: NCT03678883 .

e14555 Background: 9-ING-41 (elraglusib) is a novel inhibitor of GSK-3β that has shown early signs of clinical benefit in a phase 1/2 clinical trial (ACT1801; NCT03678883). Early data support a multi-modal mechanism of action for elraglusib that targets both the tumor and immune system. Thus, the discovery and validation of biomarkers of drug sensitivity to elraglusib is a high priority. Here, we take inspiration from the literature on checkpoint inhibitor therapy and explore the potential of cytokines to predict elraglusib clinical response. Methods: Peripheral plasma samples from 59 patients enrolled in the 1801 phase 1/2 trial of elraglusib were assayed for 40 circulating cytokine levels. Patients advanced solid tumors refractory to standard treatments and received either elraglusib (1.0-15.0 mg/kg) as a single agent or in combination with other chemotherapies. Samples were taken from time points prior to elraglusib administration (pre-dose), after cycle 1, or after cycle 2. Each cytokine time point combination was used to stratify patients into high and low categories using an optimal cut-point determined using maximally selected rank statistics. Kaplan Meier and Cox Proportional Hazards analysis was used to determine the efficacy of each cytokine as a biomarker. The change in cytokine values between pre-dose and cycle 1 or pre-dose and cycle 2 was evaluated in a similar manner. Results: A total of 142 samples spanning eight different tumor histologies were collected and analyzed. A total of 240 cytokine-timepoint combinations were evaluated, and 53 significantly stratified patients by overall survival (p-value < 0.05). Of those, 35 showed that higher levels of the given cytokine correlated with a survival benefit and 18 a survival decrease. Notable among the cytokines demonstrating survival benefits were Granzyme B at Cycle 1 Day 4 (HR: 9.54, p-value:0.015) and TGF β at Cycle 1 Day 4 (HR: 8.48, p-value:0.0063). Strong hazard ratios were also observed for cytokines that correlated with survival decreases including TRAIL-R2 at Cycle 1 Day 2 (HR: 9.56e-02, p-value:0.0001), and IL-10 at Cycle 1 Day 4 (HR: 8.77e-02, p-value:0.007). Delta between timepoints was also able to stratifying patients by overall survival. Conclusions: Plasma cytokine profiling is a promising approach for discovery and validation of biomarkers prognostic for elraglusib clinical benefit. Numerous cytokines measured pre-dose stratified patients into significant survival groups suggesting a potential strategy for patient enrichment in clinical trials of elraglusib. These initial findings are being expanded by 1) increasing the cohort to accommodate histology specific investigations; 2) examining which cytokines are elraglusib response-specific versus drug-agnostic; and 3) combining cytokines in multivariate and machine learning models for optimal predictive capacity. Clinical trial information: NCT03678883 .

2529 Background: Tumor expression of the antiphagocytic protein CD47 (integrin associated protein) may lead to immunotherapy resistance (IO-R). PF-07257876 is a novel, IgG1, Fc-active, bispecific antibody targeting CD47 and PD-L1 designed to reverse IO-R, decrease anemia risk, and eliminate a priming dose. We report a Phase 1 dose escalation study (NCT04881045) in patients (pts) with advanced solid tumors, both IO-refractory and IO-naïve. Methods: The study enrolled pts ≥18 yrs with advanced non–small-cell lung carcinoma (NSCLC) and squamous cell carcinoma of the head and neck (SCCHN) with PD-L1 expression >1% post anti-PD-1/PD-L1 therapy. Pts with other PD-L1+ tumors known to express CD47 were included (prior IO not required). Pts received PF-07257876 at escalating dose levels in 28-day cycles. Primary objectives were safety (dose-limiting toxicity [DLT] rate), tolerability, and determination of Recommended Phase 2 Dose (RP2D). Secondary and exploratory objectives included pharmacokinetics (PK), blood receptor occupancy (RO), CD47 levels by immunohistochemistry (IHC), tissue biopsy findings, and objective response rate (ORR) per RECIST v.1.1. Results: As of 20OCT2022, 18 pts were enrolled (NSCLC: n = 6; SCCHN: n = 4; other: n = 8). Median (range) age 68 (46–79) yrs. PF-07257876 was given at ascending doses, 150-2400 mg by subcutaneous (SC) injection or SC infusion every 2 weeks. 16 (89%) pts had treatment-related adverse events (TRAEs): Grades 1/2: n = 12 (67%); Grade 3: n = 1 (6%); Grade 4: n = 3 (17%); no Grade 5. Most common TRAEs: injection site reaction/erythema (n = 13, 72%), thrombocytopenia (n = 6, 33%), anemia (n = 5, 28%), and nausea (n = 4, 22%). DLTs occurred in 2 of 3 pts at the highest tested dose (Grade 4 neutropenia and thrombocytopenia, n = 1; Grade 4 thrombocytopenia, n = 1; both pts recovered). One pt with IO-R SCCHN had a confirmed partial response (duration of response 16 wks). ORR was 5.6% (1/18). Drug exposure increase after 1st dose was not dose proportional. Blood RO was > 95% for PD-L1 and > 70% for CD47 with drug exposure. All pts’ baseline CD47 IHC levels were moderate to high. Pharmacodynamics cytokine profiling showed notable dose-response increases of IFNg, TNFa, CXCL9/10, CCL3/4, without IL-6 increase. Conclusions: PF-07257876 was well tolerated with manageable toxicity. Incidence and grade of anemia or thrombocytopenia were manageable. Target engagement of CD47 and PD-L1 in peripheral blood was high. Innate and adaptive cytokine modulation was observed. Antitumor activity was modest. Expansion is ongoing at 1800 mg. Clinical trial information: NCT04881045 .

Abstract 9-ING-41 (elraglusib) is a potent and selective GSK-3 inhibitor that has shown anti-tumor activity in patient-derived xenograft models and phase1/2 clinical studies in patients (pts) with advanced solid tumors. Preclinical studies have demonstrated that elraglusib downregulates PD-1, TIGIT and LAG-3, upregulates expression of MHC class I proteins in tumor cells from “cold tumors”, and shows synergy when combined with PD-1 blockade in mouse xenografts. Clinical activity has been observed both as a single agent and in combination with standard of care chemotherapies in several advanced cancer histologies. Here we present initial ‘omics data from our phase 1/2 study (NCT03678883; ACT1801) spanning &gt;100 pts with advanced cancer evaluating both single agent and chemotherapy combinations. The patients (pts) included in this study received elraglusib as a ≥3rd line therapy for advanced disease. Most pts with melanoma treated with elraglusib monotherapy (8/9; 89%) stayed on study for &gt;2 cycles. One patient with melanoma refractory to checkpoint inhibitors achieved a confirmed and durable CR. Clinical benefit was also observed among pts with colorectal cancer with 4/12 (33.3%) pts treated with monotherapy and 12/15 (80%) that received elraglusib plus irinotecan rechallenge stayed on study &gt;2 cycles reaching median overall survival of 106 and 211 days, respectively. Based on emerging in vivo and in vitro results demonstrating that elraglusib activates T and NK cells promoting anti-tumor immune responses, we hypothesize immunomodulation by elraglusib may be contributing to anti-tumor immune response in the 1801 trial. We have acquired TCRseq and RNAseq profiles of PBMC samples from seven patients in 1801 during the first two weeks of treatment with elraglusib monotherapy. In these pts, reduced TCR clonality was observed and specific TCR clonotypes expanded after treatment, indicating T cell activation and expansion. These pts also showed changes in PBMC populations during elraglusib therapy as measured by immune deconvolution of PBMC RNAseq. Taken together, these data support a novel, previously unrecognized immunomodulatory mechanism of action for elraglusib and could provide rationale for future clinical development of elraglusib in pts with advanced malignancies. Additional analysis from TCRseq, immune profiling and cytokine analysis from expanded cohort of pts is ongoing. Citation Format: Taylor Weiskittel, Joseph McDermott, Daniel Billadeau, Hu Li, Anwaar Saeed, Devalingam Mahalingam, Solmaz Sahebjam, Pamela Munster, Ludimila Cavalcante, Frank J. Giles, Andrew Mazar, Benedito Carneiro. Multimodal mechanism of action of the GSK-3 inhibitor 9-ING-41 (elraglusib) includes an immunomodulatory component: preliminary results from the 1801 phase 1/2 trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT222.

Abstract Introduction: ATRi and PARPi combinations kill tumor cells via synergistic modulation of complementary DDR pathways but clinical utility is limited by overlapping toxicities. A genome-wide CRISPR-Cas9 screen identified DDR alterations that sensitize tumors to the ATRi camonsertib (cam) plus PARPi. Based on preclinical models, tolerability and efficacy of cam plus PARPi given intermittently at low doses in pts with solid tumors with DDR alterations, including BRCA-mutated PARPi-resistant cancers, was evaluated. Methods: Pts (≥ 18 yrs) with relapsed/refractory (r/r) solid tumors with DDR alterations were treated with cam plus talazoparib (tala), niraparib (nira), or olaparib (ola) in 2 phase I trials (NCT04497116, NCT04972110). An adaptive BOIN design was used to optimize dose/schedule. Endpoints were safety, recommended phase II dose (RP2D), pharmacokinetics (PK), response (RECIST v1.1 [confirmed/unconfirmed], CA 125, or PSA), clinical benefit rate (CBR; RECIST/tumor marker response or treatment duration ≥ 16 wk), and ctDNA molecular response rate (MRR; best reduction in mean variant allele frequency [mVAF] ≥ 50%). Results: As of Nov 2022, 99 pts were enrolled (61 with ≥ 3 prior lines of therapy, 36 PARPi-pretreated); 43, 27, 29 pts in tala, nira, and ola combinations, respectively. Tumors included ovarian (n=20), prostate (n=13), breast (n=17), bile duct (n=3); most common genotypes were ATM (n=26), BRCA1 (n=19), and BRCA2 (n=33). Grade 3+ toxicities included reversible myelosuppression (neutropenia, anemia, and thrombocytopenia in 35%, 28%, and 14% of pts overall; 33%, 16%, and 11% at preliminary RP2Ds), fatigue (3%), and alkaline phosphatase increase (2%). Two pts discontinued treatment due to drug-related toxicity. Forty pts remain on therapy, up to 63 wks. Preliminary RP2Ds: cam 80 mg QD (d 5-7) + tala 0.25 mg QD, 1 wk on/1 wk off; cam 80 mg QD + nira 100 mg QD, 2 d on/5 d off; cam 50 mg QD + ola 100 mg BID, 3 d on/4 d off. As of abstract submission, response rate was 13% in 85 evaluable pts; CBR was 49%. Responders included pts with ovarian (n=6), bile duct (n=2), and breast, pancreatic, and carcinoma of unknown primary (n=1 each) cancers harboring alterations in BRCA1/2 (n=9), IDH1 (n=1), and ATM (n=1). Of 30 evaluable PARPi-pretreated pts, response rate was 23% and CBR was 52%. MRR was 64% (14/22 evaluable); change in mVAF correlated with a change in target lesion size (r=0.63, P=0.001). PK of each drug in the combination was consistent with respective monotherapy PK. Conclusion: Combination of cam plus PARPi at low doses on intermittent schedules was generally well-tolerated with clinical activity in DDR-aberrant tumors, including those pretreated with PARPi. RP2D optimization and translational correlative studies are ongoing. Citation Format: Timothy A. Yap, Siddhartha Yadav, Benjamin Herzberg, Benedito A. Carneiro, Elisa Fontana, Martin Højgaard, Michael J. Pishvaian, Ruth Plummer, Theresa L. Werner, Vaibhav Sahai, Stephanie Lheureux, Elizabeth K. Lee, Niharika B. Mettu, Gregory M. Cote, Joseph D. Schonhoft, Victoria Rimkunas, Ian M. Silverman, Marisa Wainszelbaum, Gerson Peltz, Adrian J. Fretland, Kezhen Fei, Danielle Ulanet, Insil Kim, Maria Koehler, Ezra Rosen, Michael Cecchini. Safety and efficacy of three PARP inhibitors (PARPi) combined with the ataxia telangiectasia- and Rad3-related kinase inhibitor (ATRi) camonsertib in patients (pts) with solid tumors harboring DNA damage response (DDR) alterations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT018.

Abstract Background GSK3β serine/threonine kinase regulates metabolism and glycogen biosynthesis. GSK3β overexpression promotes progression and resistance through NF-κB and p53 apoptotic pathways. GSK3β inhibits immunomodulation by downregulating PD-L1 and LAG-3 checkpoints and increasing NK and T-cell tumor killing. 9-ING-41, a small-molecule, selective GSK3β inhibitor, showed preclinical activity in chemo-resistant PDX glioblastoma models, including enhanced lomustine antitumor effect. Methods Refractory malignancies (n = 162) were treated with 9-ING-41 monotherapy (n = 65) or combined with 8 cytotoxic regimens after prior exposure (NCT03678883). Recurrent gliomas (n = 18) were treated with 9-ING-41 IV TIW q21day cycles at 3.3, 5, 9.3, 15 mg/kg, as monotherapy or combined with lomustine 30 mg/m² PO weekly q84day cycles. Primary objective was safety. Results RP2D of 15 mg/kg IV TIW was confirmed across all 9 regimens, no accentuated chemotherapy toxicity noted. Glioma subtypes included: 13 glioblastoma, 2 anaplastic astrocytomas, 1 anaplastic oligodendroglioma, 1 astrocytoma. Median age 52 (30–69) years; 6 female, 12 male; median ECOG 1 (0–2); median recurrences 3 (1–6). All received upfront radiation/temozolomide (18/18), plus salvage nitrosoureas (15/18), bevacizumab (8/18), TTFields (6/18), or immunotherapy (4/18). IDH/mutation(3/18); 1p19q/codeletion(1/18); MGMT/methylated(1/18). Four received 9-ING-41 monotherapy, 14 concurrent with lomustine. No severe toxicities were attributed to 9-ING-41, only mild vision changes (9/18, 50%), or infusion reactions (4/18, 22%). Lomustine-related toxicities: G3/4 thrombocytopenia (3/14, 21%), G1/2 fatigue (4/14, 28%). Median days on therapy was 55 (4–305); 1 partial response (&gt;50%) was noted. Median OS was 5.5 (95% CI: 2.8–11.4) months and PFS-6 was 16.7%. Conclusion 9-ING-41 plus/minus lomustine is safe and warrants further study in glioma patients.

Abstract BACKGROUND GSK3β serine/threonine kinase regulates metabolism and glycogen biosynthesis. GSK3β overexpression promotes tumor progression and resistance through NF-κB and p53 apoptotic pathways. GSK3β inhibits immunomodulation by downregulating checkpoints, e.g. PD-L1 and LAG-3, and increasing NK and T-cell mediated tumor killing. 9-ING-41 is a small-molecule, potent, selective GSK3β inhibitor with preclinical activity. In chemoresistant PDX glioblastoma models, 9-ING-41 enhanced lomustine antitumor effect. METHODS Patients with refractory malignancies were treated with 9-ING-41 monotherapy (n=65) or combined with 8 cytotoxic regimens after prior exposure (n=162) in the first-in-human study (NCT03678883). The recurrent gliomas subset was treated with 9-ING-41 monotherapy IV TIW q21day cycles at 3.3, 5, 9.3, 15mg/kg, or combined with lomustine 30 mg/m² PO weekly q84day cycles. Primary objective was safety and tolerability. RESULTS An RP2D of 15mg/kg IV TIW was confirmed across all 9 regimens, no accentuation of chemotherapy toxicity noted. Of 18 glioma patients enrolled, 13 were glioblastoma, 2 anaplastic astrocytomas, 1 anaplastic oligodendroglioma, and 1 diffuse astrocytoma; 6 female, 12 male; median age 52 (30-69) years; median ECOG was 1 (0-2). All received initial radiation and temozolomide (18/18), prior salvage therapies included nitrosoureas (15/18), bevacizumab (8/18), TTFields (6/18), checkpoint inhibitor (4/18). Median recurrences 3 (1-6). NGS alterations included: IDH/wildtype (11), IDH/mutation(3); 1p19q/codeletion(10); MGMT/unmethylated(11), MGMT/methylated(1); EGFR/amplification(6), EGFR/v3mutation(3), TERT/mutation(6), PTEN/loss(3), NF1/rearrangement(2), ATRX/loss (2), TP53/mutation(4), CDKN2A/deletion(2), RB1/loss(1), PALB2/mutation(10). Four patients received 9-ING-41 monotherapy, 14 concurrently treated with lomustine. No SAEs or grade 3/4 AEs attributed to 9-ING-41 noted, only G1/2 vision changes (9/18, 50%), infusion reactions (4/18, 22%). Lomustine-related toxicities included G3/4 thrombocytopenia (3/14, 21%), and G1/2 fatigue (4/14, 28%). Median therapy duration was 55 (4-305); 1 partial response ( &gt;50%) noted with 9-ING-41/lomustine. Median PFS and OS were 1.9 (0.3-11.1) and 6.0 (1.6-16.6) months, respectively. CONCLUSIONS 9-ING-41 plus/minus lomustine is safe and warrants further study in glioma patients.