Trials For Solid Tumors Research Articles

Sitravatinib as a potent FLT3 inhibitor can overcome gilteritinib resistance in acute myeloid leukemia

BackgroundGilteritinib is the only drug approved as monotherapy for acute myeloid leukemia (AML) patients harboring FMS-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) mutation throughout the world. However, drug resistance inevitably develops in clinical. Sitravatinib is a multi-kinase inhibitor under evaluation in clinical trials of various solid tumors. In this study, we explored the antitumor activity of sitravatinib against FLT3-ITD and clinically-relevant drug resistance in FLT3 mutant AML.MethodsGrowth inhibitory assays were performed in AML cell lines and BaF3 cells expressing various FLT3 mutants to evaluate the antitumor activity of sitravatinib in vitro. Immunoblotting was used to examine the activity of FLT3 and its downstream pathways. Molecular docking was performed to predict the binding sites of FLT3 to sitravatinib. The survival benefit of sitravatinib in vivo was assessed in MOLM13 xenograft mouse models and mouse models of transformed BaF3 cells harboring different FLT3 mutants. Primary patient samples and a patient-derived xenograft (PDX) model were also used to determine the efficacy of sitravatinib.ResultsSitravatinib inhibited cell proliferation, induced cell cycle arrest and apoptosis in FLT3-ITD AML cell lines. In vivo studies showed that sitravatinib exhibited a better therapeutic effect than gilteritinib in MOLM13 xenograft model and BaF3-FLT3-ITD model. Unlike gilteritinib, the predicted binding sites of sitravatinib to FLT3 did not include F691 residue. Sitravatinib displayed a potent inhibitory effect on FLT3-ITD-F691L mutation which conferred resistance to gilteritinib and all other FLT3 inhibitors available, both in vitro and in vivo. Compared with gilteritinib, sitravatinib retained effective activity against FLT3 mutation in the presence of cytokines through the more potent and steady inhibition of p-ERK and p-AKT. Furthermore, patient blasts harboring FLT3-ITD were more sensitive to sitravatinib than to gilteritinib in vitro and in the PDX model.ConclusionsOur study reveals the potential therapeutic role of sitravatinib in FLT3 mutant AML and provides an alternative inhibitor for the treatment of AML patients who are resistant to current FLT3 inhibitors.

Order of patient entry and outcomes in phase II clinical trials: A meta-analysis of individual patient data

BackgroundPrior meta-analysis of stem-cell transplantation trials for renal-cell carcinoma observed that clinical outcomes vary by subjects' order of entry, specifically their quartile of accrual. We test this hypothesis using meta-analysis of individual patient data from diverse Phase II trials conducted by an oncology consortium. MethodsEligible were all Phase II trials in hematologic or solid tumors opened and closed by California Cancer Consortium during 2005–2020. Excluded were trials closed in first quartile or currently embargoed pending publication and subjects ineligible per protocol or untreated on study. The primary risk factor was entry by quartile of planned sample size. As a cross-protocol endpoint, primary outcome was time to discontinuation of intervention. One-stage meta-analysis used a shared frailty model with trial as random effect. As covariates, stepwise selection retained tumor type, obesity, their interaction, calendar year, entry at least 3 years post-diagnosis, and performance status but rejected age, sex, randomized design, and class of drug. ResultsTwenty trials (including 8 terminated early, 2 not published) included n = 923 subjects. Most (90.6%) subjects discontinued intervention, usually for disease progression or toxicity. Independently of covariates, risk of discontinuation increased (p < 0.0001) with each quartile of entry (Hazards Ratio 1.13, 95% CI 1.06–1.22), culminating at Quartile 4 (HR 1.46, 1.36–1.57). The 95% prediction interval for the Hazards Ratio in future trials was (1.04–1.24). Progression-free survival similarly worsened by quartile of entry. ConclusionIn Phase II trials, clinical outcome worsens with quartile of entry. This finding merits independent replication, and the cause of this phenomenon merits investigation.

The natural killer cell immunotherapy platform: An overview of the landscape of clinical trials in liquid and solid tumors

The translation of natural killer (NK) cells to the treatment of malignant disease has made significant progress in the last few decades. With a variety of available sources and improvements in both in vitro and in vivo NK cell expansion, the NK cell immunotherapy platform has come into its own. The enormous effort continues to further optimize this platform, including ways to enhance NK cell persistence, trafficking to the tumor microenvironment, and cytotoxicity. As this effort bears fruit, it is translated into a plethora of clinical trials in patients with advanced malignancies. The adoptive transfer of NK cells, either as a standalone therapy or in combination with other immunotherapies, has been applied for the treatment of both liquid and solid tumors, with numerous early-phase trials showing promising results. This review aims to summarize the key advantages of NK cell immunotherapy, highlight several of the current approaches being taken for its optimization, and give an overview of the landscape of clinical trials translating this platform into clinic.

Shifting paradigms &amp; advancing technology to find I–O biomarkers

Abigail Pinchbeck, Assistant Editor, BioInsights, speaks to Mustafa Khasraw, Deputy Director of the Center for Cancer Immunotherapy, Duke Cancer InstituteMustafa Khasraw MD, is a professor of medicine and neuro-oncology and Deputy Director of the Center for Cancer Immunotherapy at Duke University, USA. He is leading several clinical and translational programs with significant laboratory collaborations and is the principal investigator on first-in-human Phase I immunotherapy clinical trials in solid tumors with a special interest in CNS cancers.The discovery of relevant biomarkers in immuno-oncology is crucial to match the right patients to the right treatments. In this interview, Mustafa Khasraw, Deputy Director of the Center for Cancer Immunotherapy at the Duke Cancer Institute, highlights the current challenges in this space – and potential approaches to overcome them.

Chimeric Antigen Receptor-Natural Killer Cells: A New Breakthrough in the Treatment of Solid Tumours

Natural killer (NK) cells can quickly and directly eradicate tumour cells without recognising tumour-specific antigens. NK cells also participate in immune surveillance, which arouses great interest in the development of novel cancer therapies. The chimeric antigen receptor (CAR) family is composed of receptor proteins that give immune cells extra capabilities to target specific antigen proteins or enhance their killing effects. CAR-T cell therapy has achieved initial success in haematological tumours, but is prone to adverse reactions, especially with cytokine release syndrome in clinical applications. Currently, CAR-NK cell therapy has been shown to successfully kill haematological tumour cells with allogeneic NK cells in clinical trials without adverse reactions, proving its potential to become an off-the-shelf product with broad clinical application prospects. Meanwhile, clinical trials of CAR-NK cells for solid tumours are currently underway. Here we will focus on the latest advances in CAR-NK cells, including preclinical and clinical trials in solid tumours, the advantages and challenges of CAR-NK cell therapy and new strategies to improve the safety and efficacy of CAR-NK cell therapy.

Lyt-200, a Humanized Anti-Galectin-9 Antibody, Exhibits Preclinical Efficacy in Models of Hematological Malignancies

Patients with relapse and refractory (R/R) hematological malignancies typically have 5-year overall survival rates of less than 50% when receiving chimeric antigen receptor (CAR) T-cell therapy and less than 30% after receiving hematopoietic stem cell transplantation (HSCT). Human leukemia cells utilize a variety of biochemical mechanisms, which allow them to escape host immune surveillance. These molecular pathways cause impairment of the anti-cancer activities of immune cells, which could attack and kill leukemia cells. These dismal outcomes for patients with R/R disease highlight the need for novel treatment regimens when current therapeutic options are exhausted. Galectins are s-type lectins that promote diverse biological processes including adhesion, signaling, and immunosuppression. In acute myeloid leukemia (AML), galectin-9 (GAL-9) maintains the leukemia initiating cell (LIC) population and plays an important role in treatment resistance. We recently tested LYT-200, a fully humanized IgG4 αGAL-9 monoclonal antibody, developed by PureTech Health, which has so far been well tolerated with no dose limiting toxicities in a Phase I clinical trial for solid tumors (NCT04666688). We tested LYT-200 in vitro and in vivo across multiple hematological malignancies. Flow cytometry was used to assess the surface expression of GAL-9 on human B-ALL, AML, T-cell acute lymphoblastic leukemia (T-ALL), and diffuse large B-cell lymphoma (DLBCL) cell lines relative to receptor T-cell immunoglobulin and mucin domain-containing protein-3 (TIM-3) and Programmed cell death protein-1 (PD-1) expression. Compared to healthy human peripheral blood mononuclear cells (PBMCs), where GAL-9 surface expression was low or absent depending on the immune cell, GAL-9 was highly expressed on the surface of all human blood cancer cell lines tested (>100-fold increase). Notably, GAL-9 expression was comparable to PD-1 surface expression and higher than that of TIM-3 on AML, B-ALL, T-ALL, and DLBCL cells. Treating all cell lines with LYT-200 relative to control immunoglobulin resulted in extensive cell death, which occurred after 48 and 72 hours of treatment. Furthermore, a side-by-side comparison with αTIM-3 antibody treatment at equivalent concentrations, revealed that LYT-200 treatment was significantly more effective at killing blood cancer cells at low doses of 10-100 ng/mL in vitro. The in vitro efficacy of LYT-200 against multiple blood cancer subtypes extended to in vivo protection and survival benefit in murine models of T-ALL and AML, both in immunocompromised and immunocompetent mice. When immunocompromised mice were transplanted with human T-ALL cell lines or patient-derived samples, single-agent treatment with LYT-200 (1.5 mg/kg/weekly) was comparable to survival results obtained with methotrexate (0.75 mg/kg/weekly) administration. Notably, the combination of LYT-200 and methotrexate treatments led to the best survival outcomes in both contexts. Similar results were obtained in xenograft studies of AML, where single-agent LYT-200 (1.5 mg/kg/weekly) treatment was more effective at protecting mice than cytarabine (100 mg/kg/weekly). However, combining both treatments resulted in the best survival outcomes with greater than 80% of mice surviving over 2 months after disease appearance. In all, our results demonstrate that GAL-9 is an important driver of multiple blood cancer subtypes and that targeting GAL-9 with LYT-200 represents a potential novel treatment strategy which warrants additional pre-clinical and clinical testing.

Addition of Metastasis-Directed Therapy to Intermittent Hormone Therapy for Oligometastatic Prostate Cancer (EXTEND): A Multicenter, Randomized Phase II Trial

<h3>Purpose/Objective(s)</h3> There has been increased utilization of metastasis directed therapy (MDT) for oligometastatic prostate cancer. Despite data demonstrating the benefit of upfront hormone therapy (HT) and synergy between radiation and HT, there exists no randomized trials testing their combination. As it is accepted by most clinicians and men with prostate cancer that time off HT holds intrinsic value, we evaluated whether the addition of metastasis directed therapy (MDT) to intermittent HT in men with oligometastatic prostate cancer facilities time off HT by improving PFS and eugonad PFS. <h3>Materials/Methods</h3> EXTEND (NCT03599765) is a phase II randomized basket trial for multiple solid tumors testing whether the addition of MDT improves PFS. The primary endpoint was pre-specified to be independently assessed and reported for the prostate intermittent HT basket at 41 events. Men with ≤5 metastases were randomized after ≥2 months of HT to continuing HT with or without MDT. HT consisted of a luteinizing hormone-releasing hormone agonist/antagonist with or without a 2^nd generation androgen-receptor targeting agent (SART). The primary endpoint was progression, defined as death or radiographic, clinical, or biochemical progression. A planned HT break occurred 6 months after enrollment, after which HT was withheld until progression. The study was designed to have 80% power to detect an improvement in median PFS from 18 to 36 months, with a type I error of 0.1. Exploratory analysis included flow cytometry and TCR sequencing from peripheral blood at baseline and 3 months follow up. <h3>Results</h3> Between Sept 2018 to Nov 2020, 87 men were randomized, 43 combined therapy and 44 to HT-only. Arms were well balanced. At a median follow-up of 22.1 months (range 13.0 to 39.3 months), 41 events were observed. PFS was improved by the receipt of MDT (median not reached vs 15.8 months for HT-only, P<0.001; HR=0.25 [95% CI, 0.12 to 0.55]). Among secondary endpoints, time from eugonad testosterone levels (>150 ng/dL) to progression was improved by MDT (median not reached vs 6.1 months, P=0.03), as was time to appearance of new lesions (2-year rate 33% vs 41%, P=0.04). Three grade 3 toxicities were observed in each arm. Subgroup analysis identified PFS improvement with MDT in patients who received (HR=0.24 [95% CI, 0.08 to 0.71]) or did not receive a SART (HR=0.36 [95% CI, 0.15 to 0.83]). Flow cytometry and TCR sequencing demonstrated increases in markers of T cell activation, proliferation, and clonal expansion limited to the combined therapy arm. <h3>Conclusion</h3> EXTEND represents the first randomized study to evaluate MDT with HT in oligometastatic prostate cancer and demonstrated improvement in PFS and eugonad PFS. Combination of MDT with intermittent HT may allow for both excellent disease control while facilitating prolonged eugonad testosterone intervals.

ERK Inhibitor Ulixertinib Inhibits High-Risk Neuroblastoma Growth In Vitro and In Vivo.

Neuroblastoma (NB) is a pediatric tumor of the peripheral nervous system. Approximately 80% of relapsed NB show RAS-MAPK pathway mutations that activate ERK, resulting in the promotion of cell proliferation and drug resistance. Ulixertinib, a first-in-class ERK-specific inhibitor, has shown promising antitumor activity in phase 1 clinical trials for advanced solid tumors. Here, we show that ulixertinib significantly and dose-dependently inhibits cell proliferation and colony formation in different NB cell lines, including PDX cells. Transcriptomic analysis revealed that ulixertinib extensively inhibits different oncogenic and neuronal developmental pathways, including EGFR, VEGF, WNT, MAPK, NGF, and NTRK1. The proteomic analysis further revealed that ulixertinib inhibits the cell cycle and promotes apoptosis in NB cells. Additionally, ulixertinib treatment significantly sensitized NB cells to the conventional chemotherapeutic agent doxorubicin. Furthermore, ulixertinib potently inhibited NB tumor growth and prolonged the overall survival of the treated mice in two different NB mice models. Our preclinical study demonstrates that ulixertinib, either as a single agent or in combination with current therapies, is a novel and practical therapeutic approach for NB.

1626P Time trends (2012-2016 vs 2017-2021) in health-related quality of life (QoL) assessment and reporting in oncology: A systematic review of randomized phase III trials

In our previous systematic review (Marandino et al, Ann Oncol 2018) of phase III trials in solid tumors published between 2012 and 2016, we showed that QoL was not included among endpoints and QoL results were underreported in a relevant proportion of trials. To assess time trends in QoL inclusion among endpoints and reporting of QoL results in publications, we reviewed phase III oncology trials published in major journals in 2017-2021, compared to the previous 5 years.

762P Personalized immunotherapy with encapsulated cell technology: Feasibility, safety and efficacy results from the first-in-human clinical trial in advanced relapsing solid tumors

Preclinical data shows that sustained, local delivery of low doses of GM-CSF by irradiated, genetically engineered tumor cells at the immunization site leads to specific, long-lasting anti-tumor immunity in several tumor types. Providing sustained levels of GM-CSF SC in a clinical setting remains challenging. Encapsulated Cell Technology enables the sustained and controlled delivery of GM-CSF by allogeneic cells. MVX-ONCO is an active, personalized cancer immunotherapy combining irradiated autologous tumor cells and encapsulated, genetically engineered allogeneic cells producing GM-CSF.

An optimized bicistronic chimeric antigen receptor against GPC2 or CD276 overcomes heterogeneous expression in neuroblastoma.

Chimeric antigen receptor (CAR) T cell therapies targeting single antigens have performed poorly in clinical trials for solid tumors due to heterogenous expression of tumor-associated antigens (TAAs), limited T cell persistence, and T cell exhaustion. Here, we aimed to identify optimal CARs against glypican 2 (GPC2) or CD276 (B7-H3), which were highly but heterogeneously expressed in neuroblastoma (NB), a lethal extracranial solid tumor of childhood. First, we examined CAR T cell expansion in the presence of targets by digital droplet PCR. Next, using pooled competitive optimization of CAR by cellular indexing of transcriptomes and epitopes by sequencing (CITE-Seq), termed P-COCC, we simultaneously analyzed protein and transcriptome expression of CAR T cells to identify high-activity CARs. Finally, we performed cytotoxicity assays to identify the most effective CAR against each target and combined the CARs into a bicistronic “OR” CAR (BiCisCAR). BiCisCAR T cells effectively eliminated tumor cells expressing GPC2 or CD276. Furthermore, the BiCisCAR T cells demonstrated prolonged persistence and resistance to exhaustion when compared with CARs targeting a single antigen. This study illustrated that targeting multiple TAAs with BiCisCAR may overcome heterogenous expression of target antigens in solid tumors and identified a potent, clinically relevant CAR against NB. Moreover, our multimodal approach integrating competitive expansion, P-COCC, and cytotoxicity assays is an effective strategy to identify potent CARs among a pool of candidates.

Early drug development in solid tumours: analysis of National Cancer Institute-sponsored phase 1 trials

The low expectation of clinical benefit from phase 1 cancer therapeutics trials might negatively affect patient and physician participation, study reimbursement, and slow the progress of oncology research. Advances in cancer drug development, meanwhile, might have favourably improved treatment responses; however, little comprehensive data exist describing the response and toxicity associated with phase 1 trials across solid tumours. The aim of the study is to evaluate the trend of toxicity and response in phase 1 trials for solid tumours over time. We analysed patient-level data from the Cancer Therapy Evaluation Program of the National Cancer Institute-sponsored investigator-initiated phase 1 trials for solid tumours, from Jan 1, 2000, to May 31, 2019. We assessed risks of treatment-related death (grade 5 toxicity ratings possibly, probably, or definitely attributable to treatment), all on-treatment deaths (deaths during protocol treatment regardless of attribution), grade 3-4 toxicity, and proportion of overall response (complete response and partial response) and complete response rate in the study periods of 2000-05, 2006-12, and 2013-2019, and evaluated their trends over time. We also analysed cancer type-specific and investigational agent-specific response, and analysed the trend of response in each cancer type over time. Univariate associations of overall response rates with patients' baseline characteristics (age, sex, performance status, BMI, albumin concentration, and haemoglobin concentration), enrolment period, investigational agents, and trial design were assessed using risk ratio based on the modified Poisson regression model. We analysed 465 protocols that enrolled 13 847 patients using 261 agents. 144 (31%) trials used a monotherapy and 321 (69%) used combination therapies. The overall treatment-related death rate was 0·7% (95% CI 0·5-0·8) across all periods. Risks of treatment-related deaths did not change over time (p=0·52). All on-treatment death risk during the study period was 8·0% (95% CI 7·6-8·5). The most common grade 3-4 adverse events were haematological; grade 3-4 neutropenia occurred in 2336 (16·9%) of 13 847 patients, lymphopenia in 1230 (8·9%), anaemia in 894 (6·5%), and thrombocytopenia in 979 (7·1%). The overall response rate for all trials during the study period was 12·2% (95% CI 11·5-12·8; 1133 of 9325 patients) and complete response rate was 2·7% (2·4-3·0; 249 of 9325). Overall response increased from 9·6% (95% CI 8·7-10·6) in 2000-05 to 18·0% (15·7-20·5) in 2013-19, and complete response rates from 2·5% (2·0-3·0) to 4·3% (3·2-5·7). Overall response rates for combination therapy were substantially higher than for monotherapy (15·8% [15·0-16·8] vs 3·5% [2·8-4·2]). The overall response by class of agents differed across diseases. Anti-angiogenesis agents were associated with higher overall response rate for bladder, colon, kidney and ovarian cancer. DNA repair inhibitors were associated with higher overall response rate in ovarian and pancreatic cancer. The rates of overall response over time differed markedly by disease; there were notable improvements in bladder, breast, and kidney cancer and melanoma, but no change in the low response of pancreatic and colon cancer. During the past 20 years, the response rate in phase 1 trials nearly doubled without an increase in the treatment-related death rate. However, there is significant heterogeneity in overall response by various factors such as cancer type, investigational agent, and trial design. Therefore, informed decision making is crucial for patients before participating in phase 1 trials. This study provides updated encouraging outcomes of modern phase 1 trials in solid tumours. National Cancer Institute.

HiPSC-derived bone marrow milieu identifies a clinically actionable driver of niche-mediated treatment resistance in leukemia

SummaryLeukemia cells re-program their microenvironment to augment blast proliferation and enhance treatment resistance. Means of clinically targeting such niche-driven treatment resistance remain ambiguous. We develop human induced pluripotent stem cell (hiPSC)-engineered niches to reveal druggable cancer-niche dependencies. We reveal that mesenchymal (iMSC) and vascular niche-like (iANG) hiPSC-derived cells support ex vivo proliferation of patient-derived leukemia cells, affect dormancy, and mediate treatment resistance. iMSCs protect dormant and cycling blasts against dexamethasone, while iANGs protect only dormant blasts. Leukemia proliferation and protection from dexamethasone-induced apoptosis is dependent on cancer-niche interactions mediated by CDH2. Consequently, we test CDH2 antagonist ADH-1 (previously in Phase I/II trials for solid tumors) in a very aggressive patient-derived xenograft leukemia mouse model. ADH-1 shows high in vivo efficacy; ADH-1/dexamethasone combination is superior to dexamethasone alone, with no ADH-1-conferred additional toxicity. These findings provide a proof-of-concept starting point to develop improved, potentially safer therapeutics targeting niche-mediated cancer dependencies in blood cancers.

Tumor-treating fields in combination with sorafenib curtails the growth of colorectal carcinoma by inactivating AKT/STAT3 signaling.

BackgroundTumor-treating fields (TTFields) have been extensively used to treat various cancers as well as glioblastoma multiforme (GBM), owing to their antimitotic effects. Furthermore, sorafenib is also extensively used to treat hepatocellular carcinoma (HCC) and renal cell carcinoma (RCC) and is under phase II/III clinical trials for other solid tumors. Hence, this investigation aimed to assess the efficacy of combination therapy with TTFields and sorafenib for colorectal carcinoma (CRC).MethodsHuman CRC HCT116 and SW480 cells were subjected to cell viability assay, followed by the assessment of their cell death using fluorescence-activated cell sorting (FACS) analysis. Furthermore, the expression of proteins involved in AKT/STAT3 signaling and apoptosis was assessed via western blotting.ResultsCombination treatment inhibited cell proliferation and induced apoptosis via Reactive oxygen species (ROS) generation, evident from caspase-3 cleavage in CRC cells and suppressed the AKT/STAT3 signaling pathway, as evident from downregulation of BCL-2 after post-treatment. The present results indicate that combination treatment with TTFields and sorafenib inactivates AKT/STAT3 signaling pathway, thus altering the expression of BCL-2, thus inducing apoptosis and inhibiting the growth of CRC cells.ConclusionsThus, combination treatment with TTFields and sorafenib is clinically applicable for treating metastatic CRC, although safety examination in patients with CRC will required to be achieved before this protocol can be implemented clinically for TTFields-sensitizer.

THE ROLE OF miR-92a, PI3K/Akt/mTOR SIGNALING PATHWAY, TFFs, AND NAG-1 IN GASTRIC MUCOSA INJURY

The prevalence of stomach diseases is tremendously high, which has a significant impact on human health. Damaged gastric mucosa is more susceptible to injury, leading to bleeding and perforation,eventually exacerbating the underlying disease. Gastric ulcer (GU) is a common disease of the digestive system and is mainly caused by an imbalance between protective and aggressive factors of the gastric mucosa. Gastric cancer (GC) is one of the most common gastrointestinal cancer worldwide and has a high recurrence rate and mortality rate. Therefore, it is very important to protect the gastric mucosa. However, conventional medications that protect the gastric mucosa can cause mild side effects. In recent years, scholars at home and abroad have shown that miRNAs, PI3K/AKt/mTOR, TFFs and NAG-1 are involved in the process of gastric mucosa lesion, but the relationship between these are not clear. MicroRNAs (miRNAs) play an important role in the development of GCs. A recent study showed a significant increase in miR-92a expression in several cancers, including GC. Targeted therapies are needed for a more effective treatment of oncological diseases. PI3K/AKT/Mtor signaling pathway inhibitors include single and dual inhibitors. Many PI3K inhibitors have performed well in preclinical studies, and have entered clinically trials for hematological malignancies and solid tumors. As multiple inhibitors are developed, further studies on predictive biomarkers are needed to measure the specificity of any therapeutic intervention. Here, we briefly review recent knowledge about the PI3K/Akt/mTOR pathway and the roles of miR-92a and PI3K/Akt/mTOR pathway inhibitors in gastric cancer. We also discuss recent efforts on the mechanisms of chemical factors that regulate the gastric mucosa, such as, TFFS; NAG-1, and future perspectives on gastric mucosa protection are discussed.

Abstract 2764: Safety and efficacy of CAR T and TCR therapies in solid tumors: A systematic review and meta-analysis, including a comparison with five phase II trials in hematologic malignancies used for the first FDA approvals of these agents

Abstract Background: Adoptive cellular therapies (ACT) have met with significant success in hematologic malignancies. The number of ACT trials in solid tumors has been increasing, however data are limited on the overall safety and efficacy of ACT in this population. We aimed to conduct a systematic review and meta-analysis looking specifically at TCR and CAR-T in solid tumors and rates of cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) relative to the current approved agents in hematologic malignancies. Methods: We conducted a systematic review of published studies/abstracts from January 2015 up to and including July 2021, selecting those that included ≥ 5 patients. Endpoints included rates and differences in CRS and ICANS. Response rates were evaluated. Statistical tests in the pooled data included χ2 and multivariable logistic regression. Results: This meta-analysis included a total of 1,250 patients [566 patients with solid tumors who had received ACT in phase I, II or I/II clinical trials; a comparison was made with five phase 2 clinical trials in hematologic malignancies used for the first FDA approvals of these agents (JULIET, ZUMA-1, ZUMA-2, TRANSCEND and KARMMA), encompassing 684 heme malignant patients]. Rates of CRS of any grade, CRS ≥ grade 3, ICANS of any grade, and ICANS ≥ grade 3 in solid tumors were 33.0%, 3.8%, 2.3% and 2.1%, respectively. Fever, hypotension, and hypoxia were experienced by 37.4%, 18.5%, and 8.5% of solid tumor patients, respectively. CRS, ICANS, fever and hypoxia in solid tumor patients did not differ by whether the ACT received was TCR or CAR T. Objective response (ORR = CR + PR) in patients with solid tumors was higher with TCR compared with CAR-T [odds ratio (OR) = 3.1, P=0.001] and with NY-ESO-1 than other targets (OR=2.0, P=0.031). Compared to hematologic patients treated with ACT, solid tumor patients treated with adoptive cellular therapies were significantly less likely to experience CRS of any grade (62.4% vs. 33.0%, P&amp;lt;0.001), CRS ≥ grade 3 (7.3% vs. 3.8%, P=0.043), fever (50.3% vs. 37.4%, P=0.001), hypoxia (34.1% vs. 8.5%, P&amp;lt;0.001) or hypotension (29.5% vs. 18.5%, P=0.006), ICANS of any grade (29.7% vs. 2.3%, P&amp;lt;0.001), or ICANS ≥ grade 3 (13.9% vs. 2.1%, P&amp;lt;0.001). However, objective response (20.1% vs. 75.4%, P&amp;lt;0.001) and clinical benefit (CBR = CR + PR + SD) (62.6% vs. 90.9%, P&amp;lt;0.001) rates for ACT were lower in patients with solid tumors than in patients with hematologic malignancies. Conclusions: CRS and ICANs were less prevalent in solid tumor cellular therapies. Based on this analysis, T-cell therapies in solid tumors are relatively safe, but further studies with larger populations and longer follow up are needed to address the role of these treatments in cancer. Citation Format: Mirella Nardo, Ji Y. Son, Goldy G. George, David S. Hong. Safety and efficacy of CAR T and TCR therapies in solid tumors: A systematic review and meta-analysis, including a comparison with five phase II trials in hematologic malignancies used for the first FDA approvals of these agents [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2764.

Abstract 1057: Significant efficacy demonstrated with the combination of ulixertinib (ERK1/2 inhibitor) and CDK4/6 inhibitors in MAPK altered models

Abstract Ulixertinib (BVD-523) is a first-in-class small molecule inhibitor of ERK1/2 currently being investigated in several oncology clinical trials, both as a single agent and in combination with other anti-cancer therapeutics. Palbociclib and ribociclib are FDA approved orally active, potent, and highly selective reversible inhibitors of the CDK4 and CDK6 kinases. As it is well established that ERK activation increases cyclin D levels and entry into the cell cycle, we hypothesized that the combination of ERK1/2 and CDK4/6 inhibition would have synergistic antitumor activity and cause tumor regression in vivo. Initial in vitro work combined ulixertinib with CDK4/6 inhibitors across a small panel of lung cancer cell lines. Cell lines carrying a KRAS mutation were more sensitive to ulixertinib relative to KRAS wild type cell lines based on single agent IC50 values. The single agent IC50 values for the CDK4/6 inhibitors were dependent on whether a metabolic or non-metabolic readout for cell viability was used. The combination interactions across a dose matrix of concentrations were determined by the Loewe Additivity and Bliss Independence models. The results of combining ulixertinib and CDK4/6 inhibitors ranged from additive to potentially synergistic. The combination of ulixertinib and palbociclib was then assessed against four xenograft models representing colorectal, melanoma, and pancreatic tumor types, each harboring an alteration within a component of the MAPK pathway. Palbociclib monotherapy across all models showed limited tumor growth inhibition (TGI) while ulixertinib monotherapy demonstrated modest TGI across all models. The combination groups demonstrated significant responses ranging from 75% - 90% TGIs. All treatment regimens were well tolerated across all models. Downstream assays were completed including reverse phase protein arrays (RPPA). Using RPPA, treatment effects on protein signaling was evaluated in the MAPK family, cell cycle regulation, and other associated feedback and compensatory pathways. Notably, suppression of protein targets downstream of ERK1/2 were seen with both ulixertinib monotherapy and combination therapy. Similarly, the combination therapy group reduced protein levels involved in cell cycle progression, which was not seen in either monotherapy group alone. The efficacy demonstrated with this preclinical work has proven to be translatable to the clinic as the combination of ulixertinib and palbociclib recently achieved MTD in a Phase I trial in advanced solid tumors including pancreatic cancer (NCT 03454035). Citation Format: Caroline M. Emery, Brian Corgiat, Justin Davis, David Sorrell, Mitch Johnson, Brent Kreider, Deborah Knoerzer. Significant efficacy demonstrated with the combination of ulixertinib (ERK1/2 inhibitor) and CDK4/6 inhibitors in MAPK altered models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1057.

Abstract 3272: Attenuation of HER3-EGFR signaling augments antitumor activity of panobinostat in triple negative breast cancer

Abstract Introduction: Histone deacetylases (HDACs) are dysregulated in human cancers, making them a valuable therapeutic target. The pan-HDAC inhibitor (HDACi) panobinostat is an approved anticancer drug for patients with multiple myeloma. It has been shown that triple negative breast cancer (TNBC), as compared to other breast cancer (BC) subtypes, is more sensitive to panobinostat. Despite the positive data observed in experimental models, to date this HDACi (panobinostat) has not yielded promising results in clinical trials for most solid tumors, including BC. Thus, a better understanding of the molecular mechanisms underlying the action of panobinostat is required to design effective therapeutic strategies against TNBC. Methods: Cell growth MTS assays and LIVE/DEAD cell viability assays were used to determine cell viability. Co-immunoprecipitation (Co-IP) and Western blot were performed to assess the expression, interaction and activation of proteins. Quantitative real-time PCR (qRT-PCR) assays were carried out to measure the expression levels of mRNAs. Lentiviral vectors containing cDNA or specific shRNAs were used to overexpress or knockdown gene expression. Tumor xenograft models via subcutaneous inoculation of MDA-MB-231 cells into nude mice were established to test the in vivo antitumor activity of panobinostat alone or its combination with the EGFR inhibitor gefitinib. Results: Elevated expression of HDAC1/2/3 was observed in BC and significantly associated with poor prognosis in BC patients. In general, all TNBC cells were sensitive to panobinostat-induced growth inhibition and apoptosis. However, in the TNBC cells with HER3-low/undetectable expression, treatment with panobinostat induced upregulation of HER3, and increased the levels of phosphorylated HER3 (p-HER3) and Akt (p-Akt). Specific knockdown of HER3 via shRNAs or inhibition of HER3 by our monoclonal antibody (4A7) sensitized TNBC cells to panobinostat-induced growth inhibition and apoptosis. Further studies revealed an enhanced interaction between HER3 and EGFR due to panobinostat-induced upregulation of HER3. Combinations of panobinostat and the EGFR inhibitor gefitinib exhibited a synergistic effect inhibiting cell growth and promoting apoptosis in TNBC cells. Moreover, in the tumor xenograft models established with MDA-MB-231 cells, panobinostat in combination with gefitinib significantly inhibited tumor growth and induced apoptosis in vivo. Conclusion: While panobinostat exhibits potent anti-proliferative/anti-survival activity in TNBC cells, upregulating HER3 may be an adaptive response compromising the therapeutic potential of panobinostat. Simultaneous targeting of HER3 and its oncogenic dimerization partner, such as EGFR holds promise to combat the compensatory signaling-initiated by HER3. This new therapeutic strategy potentially improves the outcomes of TNBC patients. Citation Format: Hui Lyu, Sanbao Ruan, Congcong Tan, Bolin Liu. Attenuation of HER3-EGFR signaling augments antitumor activity of panobinostat in triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3272.

Abstract 2602: Combined inhibition of AXL and ATR enhances cell death and immune response in small cell lung cancer

Abstract Small cell lung cancer (SCLC) is an aggressive lung tumor of neuroendocrine origin with a dismal 5-year survival rate. Despite high response rates to initial therapy, rapid development of therapeutic resistance limits overall survival. There are also limited treatment options, particularly in the relapsed setting. Our group and others have shown that AXL, a TAM family receptor tyrosine kinase that is highly expressed in mesenchymal tumors, mediates resistance to chemotherapy, radiation and targeted therapies in SCLC, non-small cell lung cancer and other cancers, through its roles in driving epithelial to mesenchymal transition and DNA damage repair. AXL has also been implicated in immune escape. Based on these findings, we hypothesize that AXL targeting may be a potential therapeutic approach in SCLC. We screened BGB324 (bemcentinib), a selective small-molecule AXL inhibitor in clinical trials for various advanced solid tumors, in a panel of 60 human SCLC cell lines using cell viability assays. The SCLC cell lines showed a range of sensitivities, with IC50 values ranging from 41 nM to 10 µM (median IC50 3.1 µM) with NeuroD1-driven SCLC cell lines being highly sensitive to BGB324 (ANOVA p&amp;lt;0.05). BGB324 also showed potent inhibition of tumor growth in an in vivo SCLC model. BGB324 further combined synergistically with an ATR inhibitor (AZD3738) and induces significant DNA damage. In a syngeneic model of SCLC, the combination of BGB324, AZD6738 and an anti-PDL1 antibody combination also induced significant tumor regression. Together, these promising findings show that AXL inhibition may be effective in SCLC and support further investigation of AXL and ATR inhibitor combinations with immune checkpoint blockade. Citation Format: Kavya Ramkumar, Azusa Tanimoto, C. Allison Stewart, Qi Wang, Li Shen, Robert J. Cardnell, B. Leticia Rodriguez, Don L. Gibbons, Jing Wang, Carl M. Gay, Lauren A. Byers. Combined inhibition of AXL and ATR enhances cell death and immune response in small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2602.

Abstract 5425: Quantitative determination of fibroblast growth factor receptor inhibitor-AZD4547 using HPLC analysis in a mouse model of ultraviolet B (UVB)-induced skin carcinogenesis

Abstract Cutaneous squamous cell carcinoma (cSCC) is the second most common form of skin cancer affecting more than two million Americans annually. Cumulative sun exposure plays a leading role in the pathogenesis of cSCC. In our previous studies, topical application of Fibroblast growth factor receptor (FGFR) inhibitor AZD4547 was associated with a significant reduction in Ultraviolet B-induced (UVB)-induced acute skin changes such as epidermal hyperplasia and hyperproliferation. Further, chronic, topical application of AZD4547 was associated with significant inhibition in UVB-induced tumor incidence and multiplicity. Unfortunately, oral administration of FGFR inhibitors in clinical trials for solid tumors is associated with notable side effects such as hyperphosphatemia, diarrhea, decreased appetite, fatigue, and liver dysfunction. Therefore, our objective was to investigate whether topical administration of AZD4547 could potentially circumvent systemic absorption, leading to a low toxicity profile. Accordingly, mice were topically administered AZD4547 (400ug/200ul acetone) followed by exposure to UVB three times a week for two weeks. Blood was collected at the end of the study. AZD4547 was extracted using methanol extraction and concentrated using a Savant SpeedVac system. Samples were reconstituted in 25% acetone/75% water solution and analyzed using Reverse-phase HPLC (Shimadzu) with a Zorbax Eclipse C18 3.5-µm 4.6x100mm analytical column operated at ambient temperature and gradient elution using trifluoroacetic acid (TFA) (Mobile A) and 0.1% TFA in Acetonitrile. Data from HPLC analysis demonstrated non-appreciable absorption of AZD4547 (blood levels only from 108-358nM) suggesting that the topical application of AZD4547 was not systemically absorbed and the effect of treatment was restricted to the local skin tissue. Based on the efficacy and low systemic absorption profile, AZD4547 could potentially be utilized as a topical agent to both prevent and treat UVB-induced cSCC. Citation Format: Rema Anisha Kandula, Katherine Claire Babin, Brian Latimer, Kenneth Mc Martin, Lauren Linquest, Tara Moore-Medlin, Megha A. Thakur, Alok R. Khandelwal, John DiGiovanni, Cherie-Ann O. Nathan. Quantitative determination of fibroblast growth factor receptor inhibitor-AZD4547 using HPLC analysis in a mouse model of ultraviolet B (UVB)-induced skin carcinogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5425.