Münster, Pamela N.

TPS8598 Background: Peritoneal mesothelioma is a rare and poorly studied disease with few treatment options. For patients who are not surgical candidates, treatment recommendations for systemic therapy have been extrapolated from clinical trials for pleural mesothelioma that commonly exclude patients with peritoneal mesothelioma. Recently, the combination of the PD-1 inhibitor nivolumab and the CTLA-4 inhibitor ipilimumab received FDA-approval for the frontline treatment of non-resectable pleural mesothelioma. Additionally, a prospective, non-randomized phase 2 trial demonstrated activity with combined PD-L1 (atezolizumab) and VEGF (bevacizumab) blockade in peritoneal mesothelioma. In parallel, encouraging activity with combined chemo-immunotherapy has been reported in pleural mesothelioma. Given the benefits observed with immunotherapy, and the potential to improve upon those with chemotherapy and VEGF inhibition, we seek to determine whether the addition of the PD-L1 inhibitor atezolizumab improves outcomes with chemotherapy and bevacizumab in patients with newly diagnosed peritoneal mesothelioma. Methods: A092001 is a prospective, randomized phase 2 clinical trial. All patients with newly diagnosed peritoneal mesothelioma will be randomized 1:1 using a dynamic allocation Pocock-Simon procedure to receive carboplatin, pemetrexed, and bevacizumab, with or without atezolizumab, every 21 days for four cycles. Patients who are eligible to proceed with surgery after four cycles of therapy will then do so. Patients who are not eligible to proceed with surgery may receive maintenance bevacizumab and atezolizumab, or second-line atezolizumab with bevacizumab until progression of disease or toxicity. The primary objective is to determine whether frontline treatment with carboplatin, pemetrexed, bevacizumab and atezolizumab results in a superior best response rate (RR) to carboplatin, pemetrexed and bevacizumab as determined by RECIST. With 31 eligible patients per arm (62 eligible total), this randomized design has 80% power to detect an improvement in the RR from 20% to 45%, with a 1-sided significance level of 0.10 where an interim futility analysis will be conducted after 32 patients are enrolled. As stratification factors we have included eligibility for cytoreductive surgery at diagnosis, and histologic subtype. Secondary endpoints include assessment of progression-free survival, overall survival, and adverse events. As integrated biomarkers, we will determine if soluble mesothelin-related peptides and megakaryocyte potentiating factor correlate with responses. This trial was recently approved by the National Cancer Institute Central IRB and is activating at sites across the country. Support: U10CA180821, U10CA180882. Clinical trial information: NCT05001880.

3084 Background: Homologous recombination (HR) is an essential, high-fidelity mechanism to repair DNA double strand breaks (DSBs) in cancer cells. CYT-0851 inhibits HR leading to an accumulation of unrepaired DSBs and tumor cell death. We are reporting the completed Phase 1 dose-escalation results and RP2D selection to support ongoing development of CYT-0851. Methods: Patients (pts) with advanced hematologic and solid tumors were treated with continuous 28-day cycles of increasing doses of CYT-0851 following a 3+3 design. The primary objective was determining the maximum tolerated dose. Secondary objectives included safety, pharmacokinetics, and anti-tumor activity. Results: As of a 15 Nov 2021 data cutoff (DCO), 73 pts with advanced cancers (NHL n = 18; Sarcoma n = 16; Pancreas n = 11; Breast n = 8; HNSCC n = 6; Ovarian n = 4; SCLC n = 4; Other n = 4; Myeloma n = 2) were treated in 12 cohorts (total daily doses: 30 mg to 1200 mg). One pt experienced a dose-limiting toxicity (DLT) of reversible metabolic acidosis at 1200 mg. Two of 3 pts at 800 mg experienced reversible DLT-like events in Cycle 2 of Gr3 dry skin and Gr3 myalgia and polyarthritis, respectively. Three of 10 pts treated at 600 mg experienced DLT-like events in Cycle 1: 1 pt experienced an SAE of Gr3 anorexia with Gr3 stomatitis, vomiting, and dehydration and 2 pts had Gr3 fatigue. No DLTs occurred at 400 mg daily which was selected as the RP2D. 42 pts (57.5%) experienced a CYT-0851-related adverse event (AE), including 12 (16.4%) with a Gr3/4 AE. There were no treatment-related deaths. AE leading to CYT-0851 withdrawal were reported in 2 pts (2.7%) treated with 600 and 800 mg. The most common CYT-0851-related AEs were primarily Gr1/2 and included fatigue (20.5%), hyperuricemia (11%), nausea (11%), alopecia (9.6%), constipation (8.2%) and headache (8.2%). CYT-0851 exposure was approximately dose-proportional across the evaluated doses with an effective half-life of ̃3 days. Exposure at 400 mg daily was consistent with efficacy in preclinical models. 46 pts were evaluable for response at the DCO. 12 pts with NHL were evaluable by Lugano and included 1 CR in FL and 1 PR in DLBCL treated for 393+ and 244 days respectively. 34 pts with solid tumors were evaluable by RECIST v1.1 with 1 PR in a pt with myxofibrosarcoma treated for 313 days and 16 pts with stable disease. Fifteen pts were treated for 100+ days and 5 for 180+ days. Conclusions: CYT-0851 has demonstrated promising and broad clinical activity in a Ph 1 population of pts with advanced cancers. The safety profile is favorable as characterized by events that were infrequent, primarily Gr1/2, and reversible. Six expansion cohorts (DLBCL, Follicular Lymphoma, Myeloma, Pancreatic, Ovarian and Sarcoma) are enrolling to characterize activity at the RP2D. Ph 1 evaluation of CYT-0851 in combination with 3 chemotherapy backbones is also ongoing. Clinical trial information: NCT03997968.

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 (>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 ( >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.

2051 Background: GSK-3β, a serine/threonine kinase, is a key regulator of metabolism and glycogen biosynthesis. GSK-3β aberrant overexpression promotes tumor progression and chemotherapy resistance through NF-κB and p53-mediated apoptotic pathways. GSK-3β inhibition impacts immunomodulation through downregulation of checkpoints, such as PD-L1 and LAG-3, and increasing NK and T-cell mediated killing of tumor cells. 9-ING-41 is a small-molecule potent selective GSK-3β inhibitor with preclinical antitumor activity against several tumor types. In chemoresistant PDX models of glioblastoma (GBM), 9-ING-41 enhanced the antitumor effect of CCNU and CPT-11. Methods: In the first-in-human study (NCT03678883), patients (pts) with refractory malignancies received 9-ING-41 monotherapy (n = 65) or in combination with one of 8 cytotoxic regimens after prior treatment with the same chemotherapy (n = 162). We report the subset of pts with recurrent gliomas treated with 9-ING-41 monotherapy IV twice a week in 21-day cycles at different dose levels (3.3, 5, 9.3, 15mg/kg), or in combination with lomustine 30 mg/m² orally once weekly in 84-day cycles. Primary objective was safety and tolerability. Results: An RP2D of 15mg/kg IV was confirmed across all 9 regimens, no accentuation of chemotherapy-related toxicity noted. Of 18 glioma patients enrolled, 13 were GBM, 2 anaplastic astrocytomas, 1 diffuse astrocytoma, and 1 anaplastic oligodendroglioma. Four patients received single agent 9-ING-41, 14 treated concurrently with lomustine. Demographics: 6 female, 12 male; median age 52 (30-69) years; median ECOG was 1 (0-2). All received first-line radiation and temozolomide (18/18), prior therapies for recurrences included nitrosoureas (15/18), bevacizumab (8/18), TTFields (6/18), immune checkpoint inhibitor (4/18). Median recurrences 3 (1-6). Genomic alterations from available NGS reports included: IDH WT (11), IDH mutation (3), MGMT promoter unmethylated (11), MGMT promoter methylated (1), 1p19q co-deletion (10), EGFR amplification (6), EGFR v3 mutation (3), TERT promoter mutation (6), PTEN loss (3), NF1 rearrangement (2), ATRX loss (2), TP53 mutated (4), CDKN2A deletion (2), RB1 loss (1), PALB-2 mutation (10). No SAEs or grade 3/4 AEs attributed to 9-ING-41 were noted; AEs included G1/2 transient vision changes (9/18, 50%), infusion reactions (4/18, 22%). Side effects from lomustine included: G3/4 thrombocytopenia (3/14, 21%), and G1/2 fatigue (4/14, 28%). Best overall response: 1 minimal response (-43%) after 2 cycles of 9-ING-41 and lomustine. Median days on therapy was 55 (4-305), 4/18 (22%) were stable for 20 weeks or longer. Conclusions: These results show 9-ING-41 alone or in combination is safe and warrants further study in glioma patients. Clinical trial information: NCT03678883.

Uveal melanoma is a rare form of melanoma with particularly poor outcomes in the metastatic setting. In contrast with cutaneous melanoma, uveal melanoma lacks BRAF mutations and demonstrates very low response rates to immune-checkpoint blockade. Our objectives were to study the transcriptomics of metastatic uveal melanoma with the intent of assessing gene pathways and potential molecular characteristics that might be nominated for further exploration as therapeutic targets. We initially analyzed transcriptional data from The Cancer Genome Atlas suggesting PI3K/mTOR and glycolysis as well as IL6 associating with poor survival. From tumor samples collected in a prospective phase II trial (A091201), we performed a transcriptional analysis of human metastatic uveal melanoma observing a novel role for epithelial-mesenchymal transition associating with survival. Specifically, we nominate and describe initial functional validation of neuropillin-1 from uveal melanoma cells as associated with poor survival and as a mediator of proliferation and migration for uveal melanoma in vitro. These results immediately nominate potential next steps in clinical research for patients with metastatic uveal melanoma.

3507 Background: Overexpression of GSK-3β, a serine/threonine kinase, is associated with advanced stage malignancies, aggressive tumor growth, and chemotherapy resistance. 9-ING-41 is a GSK-3β inhibitor with significant broad spectrum pre-clinical antitumor activity, including chemotherapy-resistant models. This first-in-human study (NCT03678883) is evaluating the safety, pharmacokinetics (PK), and efficacy of 9-ING-41 monotherapy and in combination with chemotherapy in patients (pts) with refractory malignancies. Methods: 9-ING-41 is given intravenously (IV) twice-weekly as a single-agent (21-day cycle) or combined with gemcitabine, gemcitabine/nab-paclitaxel, carboplatin, carboplatin/paclitaxel, doxorubicin, lomustine or irinotecan in patients previously treated with the same chemotherapy. Results: As of Jan 2020, 101 pts were enrolled. Tumor types: 25 pancreatic (PDAC), 14 colorectal (CRC), 10 non-small cell lung cancer (NSCLC), 8 GBM and other gliomas, 7 melanoma, 5 appendiceal, 4 breast (BC), 30 others. Seven single agent dose levels (DL) completed (1, 2, 3.3, 5, 7, 9.3, 12.4 mg/kg) without any 9-ING-41-attributable SAEs. 9-ING-41 attributable AEs include: transient visual change (color perception; n = 29), starting at DL 3 (3.3mg/kg), all G1/2; infusion reactions (n = 14), all G1/2, starting at DL 5 (7mg/kg). 9-ING-41’s mean terminal half-life is 12-20 hrs. Cmax and AUC0-72, are dose proportional with no accumulation. One BRAFV600K-mutated melanoma with > 20 brain metastases, post checkpoint/BRAF/MEK failure has an ongoing CR starting at cycle 2 and sustained after 9 months on treatment. 32 (31%) pts had SD as best response (6 PDAC, 6 CRC, 3 appendiceal, 2 BC, 2 salivary gland, 2 melanoma, 1 Merkel cell, 2 GBM/glioma, 1 RCC, 1 HCC, 1 NSCLC, 1 esophageal, 1 parotid gland, 1 nasopharyngeal, 1 peritoneal, 1 T cell-ALL). 8 pts remained on study treatment > 5 months (1 melanoma, 3 PDAC, 1 appendiceal, 1 GBM, 1 peritoneal, 1 salivary gland) with median treatment duration of 198 days (range 163-261). 32 pts continue to receive 9-ING-41. Conclusions: 9-ING-41 has dose-proportional PK, is well tolerated with significant antitumor activity as monotherapy and in combination with chemotherapy in pts with refractory tumors. 1 ongoing CR was observed in a refractory BRAF-mutated melanoma. A biologically active dose has been reached, although MTD has not been determined. Enrollment is ongoing. Clinical trial information: NCT03678883 .

Abstract Background: We have previously identified Glycogen Synthase Kinase-3 beta (GSK-3β) nuclear accumulation as a hallmark of pancreatic ductal adenocarcinoma (PDAC) and demonstrated the antitumor effects of GSK-3β tool compound inhibitors in vivo (Ougolkov, Clin Cancer Res 2006). 9-ING-41 (Actuate Therapeutics Inc), a first-in-class, small-molecule potent selective GSK-3β inhibitor, has significant preclinical antitumor activity in PDAC. 9-ING-41 is synergistic with gemcitabine (GEM) in significantly reducing PDAC cell proliferation via impairment of ATR/Chk1 DNA damage response (Ding, Clin Cancer Res 2019). These data provided the rationale for inclusion of patients with PDAC in the 1801 phase 1/2 study evaluating 9-ING-41 alone and in combination with chemotherapy, including GEM and GEM plus nab-paclitaxel. Methods: Parts 1 and 2 of the 1801 phase 1/2 study evaluate the safety and tolerability of 9-ING-41 in patients with refractory malignancies. Part 1 establishes the recommended phase 2 study dose (RP2D) for 9-ING-41 monotherapy, while Part 2 assesses 9-ING-41 in combination with chemotherapies. For Part 1, patients received twice-weekly IV infusions of 9-ING-41 (21-day cycle). Based on prior treatment, Part 2 for those with PDAC consists of 9-ING-41 plus GEM (1000 to 1250 mg/m2 days 1 and 8; 21-day cycle) or 9-ING-41 plus GEM and nab-paclitaxel (125 mg/m2). Part 3 (Simon 2-stage phase 2 at the RP2D) will assess clinical benefit in patients with refractory PDAC treated with 9-ING-41-based combinations at the RP2D established in Part 2. Response is defined by response evaluation criteria in solid tumors (RECIST) criteria in evaluable lesions. The study is opening in 25 sites globally and will accrue approximately 300 patients. Results: To date, the study has accrued 34 patients with advanced solid tumors (n=33) or hematologic malignancies (n=1). Four dose levels (1, 2, 3.3, and 5 mg/kg) have been completed without dose-limiting toxicities (DLT). Part 2 of the study evaluating combination of 9-ING-41 with chemotherapy agents has been activated. Six patients with advanced PDAC have enrolled. One patient has completed 5 cycles of treatment with 9-ING-41 (1mg/kg) with stable disease (SD) as the best response. Another patient with SD as the best response has completed 6 cycles and now is joining the arm combining 9-ING-41 with GEM after disease progression. Four additional patients are awaiting first response assessment with enrollment ongoing. 9-ING-41-attributable AE to date are Grade 1 transient visual changes (color perception). Conclusions: 9-ING-41 is well tolerated. Preclinical data support the inclusion of patients with advanced PDAC on clinical studies of 9-ING-41. Citation Format: Benedito A. Carneiro, Malika Dhawan, Brittany Borden, Ludimila Cavalcante, Howard Safran, Andrey Ugolkov, Andrew P. Mazar, Daniel D. Billadeau, Francis J. Giles, Pamela Munster. GSK-3β blockade with 9-ING-41 in pancreas cancer: The 1801 phase 1/2 study [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr B09.

8522 Background: CC-223 is an ATP-competitive inhibitor of the mTOR kinase, including both TORC1 and TORC2 complexes. CC-223 was selected to address resistance of rapamycin analogues mediated by TORC2 activation. Methods: Following establishment of the MTD (reported at ASCO 2012), subjects with advanced DLBCL, MM and select solid tumors were enrolled in parallel expansion cohorts of up to 20 evaluable subjects. CC-223 was dosed at 45 mg once daily in 28 day cycles until disease progression. Results: As of 09 January, 2013, 35 subjects were enrolled including DLBCL (21) and MM (14). Results in solid tumor cohorts are reported separately. The most common (> 20%) related adverse events (all grades) were fatigue, hyperglycemia, rash, anorexia, nausea, vomiting and diarrhea. In addition, related serious adverse events included infection (2), pneumonitis (1), renal insufficiency (2), pancreatitis (1) and thrombocytopenia (1). CC-223 dose reduction was required in 9 subjects (27%), usually during cycle 1 or 2, and 4 additional subjects with DLBCL dropped out during cycle 1 due to toxicity. Systemic exposure was similar between the two tumor cohorts and was associated with inhibition of TORC1 (p4EBP1) and TORC2 (pAKT) biomarkers in blood cells. Reduction in glucose uptake (32 – 98% decrease) on PET imaging at day 15 was observed in 7/7 DLBCL subjects with results currently available. Three of 17 evaluable subjects with DLBCL had partial responses (PR) after 2 cycles; two with rapid and near complete regression (> 90%) of target lesions by CT and PET with PR confirmed and treatment ongoing at 6 and 8 cycles. Both had failed multiple prior treatment regimens (5 and 3, respectively), including autologous stem cell transplant (ASCT). No responses were observed in 10/14 evaluable subjects with MM although 2 subjects have prolonged stable disease (SD) with treatment ongoing at 12 and 14 cycles. Conclusions: Encouraging signals of biomarker and clinical activity were observed in DLBCL, including two near complete responses, which are ongoing. Due to dose reductions and interruptions, a starting dose of 30 mg QD is recommended for future studies. Clinical trial information: NCT01177397.

827 Background: 9-ING-41 is a selective GSK-3β inhibitor with significant pre-clinical antitumor activity in a broad spectrum of malignancies as a single agent and in combination with cytotoxic agents. GSK-3β is a serine/threonine kinase whose overexpression is associated with advanced stage, aggressive tumor growth, and chemotherapy resistance. We report the preliminary results of patients (pts) with gastrointestinal (GI) malignancies. Methods: Phase 1b/2 study evaluating safety and efficacy of 9-ING-41 as monotherapy and combination therapy in pts with refractory cancers. 9-ING-41 is administered intravenously twice-weekly as a single agent (21-day-cycle) or combined with chemotherapy agents, including gemcitabine (GEM), nab-paclitaxel + GEM, carboplatin, or paclitaxel. Study parts 1 and 2 evaluate the safety, describe dose-limiting toxicities (DLTs), determine the maximum tolerated dose and the recommended phase 2 study dose (RP2D) for 9-ING-41 as monotherapy (Part 1) and as combination therapy (Part 2). Part 3 (Simon 2-Stage Phase 2) assess clinical benefit in pts treated with 9-ING-41-based combinations at the RP2D established in Part 2. Response is assessed by RECIST 1.1 criteria in the evaluable lesions. Results: To date, the study accrued 63 pts. Five dose levels (1, 2, 3.3, 5 and 7 mg/kg) have been completed without DLTs. Part 2 of the study evaluating 9-ING-41-based chemotherapy combinations is ongoing. Five out of nine pts with pancreas cancer (PCa) enrolled had stable disease (SD) as the best response; 2 out of 9 pts had a 40-45% decline of CA 19-9. One pt completed 6 cycles with 9-ING-41, two pts completed 4 cycles with 9-ING-41/GEM. Two active pts are receiving 9-ING-41/GEM with SD after 3 and 4 cycles. Three out of four pts with adenocarcinoma of the appendix enrolled had SD as the best response; two pts in active treatment are receiving cycles 5 and 6. One out of 13 pts with colorectal cancer had SD. 9-ING-41-attributable AE to date are reversible grade 1 transient visual changes (color perception). Conclusions: 9-ING-41 is well-tolerated with encouraging SD among heavily pretreated pts with carcinoma of the pancreas and appendix. Clinical trial information: NCT03678883.