Treatment Of Advanced Solid Tumors Research Articles

FLT3 agonists and secondary hematopoietic malignancies: a potential class effect.

Expansion of cDC cells via FLT3 agonism has promising therapeutic potential in the treatment of advanced solid tumors. Here, we discuss the results of a clinical trial using GS-3583, an FLT3 agonist, that was stopped after a patient in the study developed acute myeloid leukemia.

Abstract LB428: Discovery of KY-001:A Direct Inhibitor of TEAD-YAP Protein-Protein Interaction for the Treatment of Advanced Solid Tumors with Abnormal Hippo Signaling Pathway

Abstract Background:The Hippo signaling is an important pathway that plays a crucial role in the regulation of numerous biological processes. The binding of YAP/TAZ transcriptional coactivators to TEAD proteins is the core of Hippo signaling in regulating the expression of a variety of genes that mediate many cellular functions. Abnormalities of Hippo signaling including mutation deficiency, fusion and YAP/TAZ overexpression are often found in solid tumors associated with excessive proliferation, drug resistance, or tumor immune evasion. Blocking the Hippo transcription activation, particularly the TAP/TAZ and TEAD interaction, therefore is an attractive therapeutic strategy for the treatment of advanced solid tumors associated with Hippo dysregulation. Results:We have developed a small molecule inhibitor, KY-001, that can bind to TEAD protein and directly disrupt its interaction with YAP/TAZ, thereby blocking Hippo signaling pathway. KY-001 can bind to TEAD (1-4) proteins with strong YAP/TAZ competitive activities in biochemical assays and can inhibit TEAD-YAP mediated transcriptional signals in cell. KY-001 selectively and potently inhibits the proliferation of cancer cells harboring Hippo deficient mutations, such as mesothelioma, lung cancer and other cell lines. Importantly, KY-001 directly affects the expression of some target genes downstream of YAP/TAZ-TEAD transcription activation in cell. KY-001 can strongly inhibit tumor growth in a dose dependent manner against Hippo mutation mesothelioma cancers in two different xenograft mouse tumor models. In addition, KY-001 shows remarkable synergistic effects with EGFR or KRAS G12C inhibitors in mouse non-small lung cancer models, suggesting it may be a promise therapy for treating targeted therapy induced resistant tumors with Hippo dysregulation. Pre-clinical studies shows that KY-001 has good overall druggable profiles with good safety windows in several animal species. Collectively, KY-001 shows high potency and selectivity in vitro and strong anti-tumor activities against Hippo mutation deficient cancers in pre-clinical models. Conclusions:KY-001 is a small molecule drug candidate which directly inhibits the interactions between TEAD and YAP1/TAZ proteins, thereby blocking the transcriptional activation of downstream Hippo signaling. In various tumor models, KY-001 monotherapy shows good efficacy for Hippo mutation deficient tumors. KY-001 also synergizes with other targeted therapy such as EGFR or KRAS G12C inhibitors for treating non-small lung cancers. KY-001 is expected to enter clinical studies in H2, 2024 for the treatment of Hippo dysregulated solid tumors. Citation Format: Kehao Zhao, Yong Zhag, Yufang Shi, Jian Chen. Discovery of KY-001:A Direct Inhibitor of TEAD-YAP Protein-Protein Interaction for the Treatment of Advanced Solid Tumors with Abnormal Hippo Signaling Pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB428.

Abstract 2379: The bispecific antibody KA-3007 against B7H3 and CD28 enhances T cell activation in solid tumors

Abstract Immunotherapy, revolutionizing the treatment of advanced solid tumors by blocking PD1 signaling, faces challenges as most cancers remain unresponsive to anti-PD-1 therapy. CD28, a key immune co-stimulatory receptor on T cells, often lacks ligands expressed on tumor cells. B7H3 is highly expressed in various solid tumors. In this study, we developed a bispecific antibody (BsAb) named KA-3007, targeting B7H3 and human CD28 to activate T cells in the tumor microenvironment. KA-3007, featuring an identical light chain, was developed using our common light chain bispecific antibody discovery platform with knob-into-hole technology. This BsAb is in regular IgG1 format with mutations in the Fc domain to eliminate ADCC, ADCP, and CDC activity. Its two Fabs bind to B7H3 with high affinity and CD28 with relatively low affinity. Co-culturing T cells with tumor cells expressing B7H3 enhances T cell activation. In PBMC humanized immunodeficient mouse tumor models, KA-3007 effectively suppresses the growth of NCI-H292 tumors, with or without a PD1 antagonist antibody. Furthermore, this antibody exhibits a half-life of more than five days in the blood of Balb/c mice. Finally, we assessed the developability of KA-3007 with different treatments such as high concentration, low pH, repeated freezing and thawing, and high temperature, and it shows neither aggregation nor degradation. In conclusion, the BsAb KA-3007, developed with our common light chain antibody discovery platform, emerges as a promising pre-clinical candidate drug for the treatment of solid cancers. Citation Format: Guojin Wu, Zhengcheng Guo, Hao Peng, Feng Hao, Feng He, Jinying Ning. The bispecific antibody KA-3007 against B7H3 and CD28 enhances T cell activation in solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2379.

Abstract 3197: Addressing drug metabolism and pharmacokinetics (DMPK) challenges of small molecule-drug conjugates (SMDCs)

Abstract Background: SMDCs are gaining momentum with potential advantages over antibody-drug conjugates (ADCs), eg, better tumor penetration and lack of immunogenicity. We have developed a novel platform technology with tailored solutions for ADCs and SMDCs with intracellular and extracellular cleavage options. Key features of the SMDC technology comprise of a small molecule ligand such as an αvβ3 integrin binder showing efficient tumor homing and a linker extracellularly cleaved by neutrophil elastase (NE) in the tumor microenvironment allowing for seamless release of different payload classes.1 Our lead SMDC VIP2362 is currently in a Phase 1 clinical trial for the treatment of advanced solid tumors (NCT05712889). SMDCs often have a shorter half-life compared with ADCs, which may result in more frequent dosing schedules. Here we show significant reduction of clearance and drastic prolongation of half-life of SMDCs achieved by adding a second binding moiety. Methods: Payloads such as kinesin spindle protein inhibitors (KSPi), cyclin-dependent kinase 9 inhibitors (CDK9i), and monomethyl auristatin E (MMAE) have been linked via elastase-cleavable linkers to one or, via a branched linker, to two αvβ3 integrin binding moieties. Cytotoxicity of SMDCs was measured in cell lines with or without NE. Monovalent and bivalent SMDCs were investigated in DMPK studies in rats while monitoring the conjugate and the released payload. Results: Payloads were coupled to the NE-cleavable peptides via different linkages. MMAE was conjugated via sterically hindered ester bonds, CDK9i was conjugated via sulfoximide bonds, and KSPi payloads were coupled via amide bonds. Each of these SMDCs was highly stable in plasma and buffer. Without NE, in vitro cytotoxicity of SMDCs in each cell line was poor with IC50 in the micromolar range. In contrast, in the presence of NE, potency increased, and cytotoxicity (IC50) was in the low nanomolar to picomolar range depending on the cell line and payload. In each case, the SMDCs reached similar potency as the free payload indicating efficient cleavage of the SMDC by NE. In DMPK studies of SMDCs in rat, none or trace levels of free payload (<0.1% as compared to the respective conjugates) was measured. With each of the SMDCs and independent of the conjugated payloads, a remarkable impact on exposure was observed when attaching a second binding ligand. The SMDCs with two ligands showed a 37- to 81-fold reduced plasma clearance as compared with the respective monovalent SMDCs, which parallels a 12- to 57-fold increase in half-life (eg, 2.1 h and 28 h for mono and bivalent MMAE SMDCs respectively). Initial in vivo studies in a cell line-derived xenograft model showed efficacy of bivalent SMDCs with once weekly dosing. Conclusion: Our technology platform comprises NE-cleavable SMDCs with promising options to tune the DMPK profile for a longer half-life. 1. Lerchen et al, AACR (2023). 2. Lerchen et al, Cancers (2023). Citation Format: Anne-Sophie Rebstock, Hans-Georg Lerchen, Harvey Wong, Beatrix Stelte-Ludwig, Mareike Wiedmann, Amy J. Johnson, Raquel Izumi, Ahmed Hamdy. Addressing drug metabolism and pharmacokinetics (DMPK) challenges of small molecule-drug conjugates (SMDCs) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3197.

Abstract 2378: The triple-specific antibody KA-3003, targeting PSMA, CD28, and 4-1BB, is developed for the treatment of prostate cancer by enhancing T cell activity within the tumor

Abstract Immunotherapy, revolutionizing the treatment of advanced solid tumors by blocking PD1 signaling, has encountered a challenge in prostate cancer, exhibiting a low response ratio to anti-PD-1 therapy. Furthermore, cancer immunotherapy using 4-1BB agonists faces limited clinical development due to dose-limiting toxicity. Here, we developed a tri-specific antibody, KA-3003, targeting PSMA, CD28, and 4-1BB, with the goal of enhancing T cell activation in the tumor microenvironment. This antibody was created using our common light chain bispecific antibody discovery platform and nanobody antibody discovery platform with knob-into-hole technology. KA-3003, in IgG1 format, features mutations in the Fc domain to eliminate ADCC, ADCP, and CDC activity. It contains two identical nanobodies at the C-terminal against 4-1BB, while binding to PSMA and CD28 with two Fabs at the N-terminal, sharing an identical light chain. KA-3003 exhibits high affinity for PSMA and relatively lower affinity for CD28 and CD137. In the presence of a low concentration of CD3 antibody to stimulate T cell activation, co-culture of tumor cells expressing PSMA with primary T cells isolated from human PBMC enhances T cell activation and proliferation. In PBMC humanized immunodeficient mouse tumor models, KA-3003 effectively suppresses the growth of 22Rv1 tumors with or without a PD1 antagonist antibody. Additionally, KA-3003 has a half-life of more than five days in the blood of Balb/c mice. Finally, we assessed the developability of this antibody with different treatments such as high concentration, low pH, repeated freezing and thawing, and high temperature. KA-3003 shows neither aggregation nor degradation. In conclusion, the tri-specific antibody KA-3003, developed with our common light chain antibody discovery platform, stands out as a promising pre-clinical candidate drug for the treatment of prostate cancer. Citation Format: Guojin Wu, Zhengcheng Guo, Hao Peng, Feng Hao, Tongtong Liu, Jinying Ning. The triple-specific antibody KA-3003, targeting PSMA, CD28, and 4-1BB, is developed for the treatment of prostate cancer by enhancing T cell activity within the tumor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2378.

Abstract 2729: Discovery and characterization of LILRB2XPD-L1 bispecific antibody SPX-303

Abstract The advent of immunotherapy has led to deep and sometimes durable remissions in certain cancers. However, the variable response rates and development of resistance mechanisms pose significant challenges to the current therapies. The immunosuppressive nature in the tumor microenvironment (TME) can drive many of these observations. Reversing this immunosuppression is a promising avenue for enhancing and broadening the applicability of IO therapies. Macrophages are critically modulated by LILRB2, a pivotal receptor in their maturation and polarization to the M2 immunosupressive phenotype. We report the discovery and development of a novel anti-LILRB2/PD-L1 bispecific antibody, SPX-303, designed using an anti-LILRB2 IgG4 derived from a mouse hybridoma screen and linked with an anti-PD-L1 epitope. SPX-303 demonstrates sub-nanomolar binding affinity to both LILRB2 and PD-L1 targets, effectively blocking the interaction between LILRB2 and its ligand, as well as inhibiting PD-1 binding to PD-L1. In in vitro functional assays, SPX-303 exhibits effects comparable to the parental monomeric anti-LILRB2 (SPX-104) in redirecting macrophage polarization from M2 to M1 stage, as observed in both cultured PBMC and human monocyte-derived macrophage (HMDM) models. Furthermore, SPX-303 demonstrates a synergistic effect in inducing T cell activation in the autologous mixed lymphocyte reaction assay (auto-MLR), surpassing the effects of the anti-LILRB2 epitope (SPX-104) and the anti-PDL1 fragment (single-domain anti-PDL1) alone or in combination. In vivo experiments reveal that SPX-303 significantly inhibits tumor growth. Collectively, these results support SPX-303 as a novel therapeutic antibody that effectively enhances anti-cancer immunity in the treatment of advanced solid tumors. The pre-clinical data as well as the clinical plan of SPX-303 will be presented. Citation Format: Anthony Haight, Qian Chen, Brandon William, Dinh-Duc Nguyen, Robert Cai, Jichun Ma, Michael White, Jindong Jin, Jadon Shen, Martin Siekierzycki, Victoria Hall, Hua Jin, Roland Meier, Justin Moser. Discovery and characterization of LILRB2XPD-L1 bispecific antibody SPX-303 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2729.

Abstract 6593: Rejuvenation of tumor-infiltrating lymphocytes (TIL): A novel strategy to revitalize TIL antitumor function for cell therapy

Abstract TIL therapy is a promising approach for the treatment of metastatic solid tumors, but its efficacy is limited by T-cell exhaustion and terminal differentiation. In addition, recent studies have underscored the adverse effects of aging on T cells. Reprogramming T cells into induced pluripotent stem cells (iPSC) and differentiating them back to the T-cell lineage has proven to be complex and time-consuming. In particular for TIL applications, de novo T cell production via iPSCs requires each TCR in the final product to be derived from an independently established iPSC clone. To overcome these barriers, we developed a novel technology called Rejuvenation, which bypasses the need for reprogramming of T cells into iPSCs. Rejuvenated TIL products retain their TCR diversity while offering several significant advantages, including reduced T-cell epigenetic age, improved expansion capacity, stem cell-like phenotype, and enhanced secretion of cytokines upon activation by target antigens. In this study, we used TIL derived from patients with melanoma and NSCLC. Rejuvenated TIL were generated by the transient expression of transcription factors in a process called ‘Partial Reprogramming’ and returned back to a T-cell lineage phenotype by a process called ‘Redirection’. Partially reprogrammed TIL showed an altered morphology resembling adherent stromal cells and down-regulated conventional T-cell markers including CD3, CD4, and CD8. Redirected T cells reacquired a conventional CD4/CD8 phenotype including morphology, surface markers and function, and demonstrated decreased epigenetic age (>7 years younger, N=3). We also observed a higher proliferative capacity, improved metabolic state, and increased expression of biomarkers associated with T-cell stemness, including CCR7 and CD62L, when compared with untreated TIL. Rejuvenated TIL demonstrated improved cytokine secretion, including IFNγ, TNFα and IL-2 in functional assays. Immune repertoire analysis revealed a significant polyclonal population of putative tumor-reactive TCRs. In vivo functionality was also evaluated using a xenograft model of engineered A375 melanoma cell line that agonizes T-cells in hIL2-NOG mice. Adoptive transfer of rejuvenated TIL resulted in significantly improved suppression of tumor growth and prolonged survival compared with TIL expanded by conventional methods. These results were also confirmed in other surrogate models, including rejuvenated PBMC, TCR and CAR T cells, demonstrating the broad applicability of Rejuvenation technology. Our results indicate TIL Rejuvenation enhances the functionality and antitumor characteristics of T cells, while preserving a broad TCR repertoire. This technology holds substantial promise and may pave the way for the development of the first rejuvenated autologous polyclonal TIL therapy for treatment of advanced solid tumors. Citation Format: Raul Vizcardo, Yin Huang, Jessica Fioravanti, Takuya Maeda, Naritaka Tamaoki, Yasuhiro Yamazaki, Burak Kutlu, Kriti Bahl, Biao Wang, Zheng Zhong, Shobha Potluri, Nicholas P. Restifo, Gary Lee. Rejuvenation of tumor-infiltrating lymphocytes (TIL): A novel strategy to revitalize TIL antitumor function for cell therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6593.

A Retrospective Study of Anlotinib Combined with Anti-PD-1 Inhibitors in the 2nd or Later-Line Treatment of Advanced Solid Tumors.

To investigate the clinical efficacy and safety of anlotinib combined with anti-PD-1 inhibitors in the 2nd or later-line treatment of advanced solid tumors. A total of 63 patients with advanced solid tumors who had failed or could not endure the adverse reactions after receiving first-line or more systematic treatment in the Second Affiliated Hospital of Harbin Medical University from March 2019 to April 2023 were treated with anlotinib Hydrochloride capsule combined with anti-PD-1 inhibitors. The efficacy and adverse reactions were evaluated according to RECIST1.1 and NCICTC4.0 standards. The percentage of overall response rate of 63 patients during the combination administration indicated that complete response was 1.6% (n=1), partial response was 23.8% (n=15), stable disease was 39.7% (n=25) and progressive disease was 34.9% (n=22), yielding objective response rate (ORR) of 25.4% and disease control rate (DCR) of 65.1%. Furthermore, the median PFS of 63 patients with advanced solid tumors was 7 months and the median OS was not reached, and the median follow-up time is 4.5 months. In subgroup analysis, there was no significant difference in PFS between first-line, second-line, third-line and above (p=0.631); there was no significant difference in PFS between PD-1 positive patients and PD-1 negative patients (p=0.094); there was no significant difference in PFS between patients who had previously used anti-PD-1 inhibitors and patients who had not used before (p=0.204). The most common adverse reactions were hypertension, hand-foot syndrome, and fatigue, with an incidence of 28.4% (18/63), 25.6% (14/63), and 25.6% (14/63), respectively. Most of the adverse reactions were grade 1-2, and there were no grade 4 adverse reactions. Anlotinib combined with anti-PD-1 inhibitors demonstrated promising efficacy and tolerable safety for patients with advanced solid tumors in the 2nd or later-line treatment.

Safety and antitumour activity of cadonilimab, an anti-PD-1/CTLA-4 bispecific antibody, for patients with advanced solid tumours (COMPASSION-03): a multicentre, open-label, phase 1b/2 trial

Immune checkpoint inhibitors targeting PD-1 or CTLA-4 individually have shown substantial clinical benefits in the treatment of malignancies. We aimed to assess the safety and antitumour activity of cadonilimab monotherapy, a bispecific PD-1/CTLA-4 antibody, in patients with advanced solid tumours. This multicentre, open-label, phase 1b/2 trial was conducted across 30 hospitals in China. Patients aged 18 years or older with histologically or cytologically confirmed, unresectable advanced solid tumours, unsuccessful completion of at least one previous systemic therapy, and an Eastern Cooperative Oncology Group performance status of 0 or 1 were eligible for inclusion. Patients who had previously received anti-PD-1, anti-PD-L1, or anti-CTLA-4 treatment were not eligible for inclusion. In the dose escalation phase of phase 1b, patients received intravenous cadonilimab at 6 mg/kg and 10 mg/kg every 2 weeks. In the dose expansion phase of phase 1b, cadonilimab at 6 mg/kg and a fixed dose of 450 mg were given intravenously every 2 weeks. In phase 2, cadonilimab at 6 mg/kg was administered intravenously every 2 weeks in three cohorts: patients with cervical cancer, oesophageal squamous cell carcinoma, and hepatocellular carcinoma. The primary endpoints were the safety of cadonilimab in phase 1b and objective response rate in phase 2, based on the Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1. The safety analysis was done in all patients who received at least one dose of cadonilimab. Antitumour activity was assessed in the full analysis set for the cervical cancer cohort, and in all patients with measurable disease at baseline and who received at least one dose of cadonilimab in the oesophageal squamous cell carcinoma and hepatocellular carcinoma cohorts. The study is registered on ClinicalTrial.gov, NCT03852251, and closed to new participants; follow-up has been completed. Between Jan 18, 2019, and Jan 8, 2021, 240 patients (83 [43 male and 40 female] in phase 1b and 157 in phase 2) were enrolled. Phase 2 enrolled 111 female patients with cervical cancer, 22 patients with oesophageal squamous cell carcinoma (15 male and seven female), and 24 patients with hepatocellular carcinoma (17 male and seven female). During dose escalation, no dose-limiting toxicities occurred. Grade 3-4 treatment-related adverse events occurred in 67 (28%) of 240 patients; the most frequent grade 3 or worse treatment-related adverse events were anaemia (seven [3%]), increased lipase (four [2%]), decreased bodyweight (three [1%]), decreased appetite (four [2%]), decreased neutrophil count (three [1%]), and infusion-related reaction (two [1%]). 17 (7%) patients discontinued treatment due to treatment-related adverse events. 54 (23%) of 240 patients reported serious treatment-related adverse events, including five patients who died (one due to myocardial infarction; cause unknown for four). In phase 2, in the cervical cancer cohort, with a median follow-up of 14·6 months (IQR 13·1-17·5), the objective response rate was 32·3% (32 of 99; 95% CI 23·3-42·5). In the oesophageal squamous cell carcinoma cohort, with a median follow-up of 17·9 months (IQR 4·0-15·1), the objective response rate was 18·2% (four of 22; 95% CI 5·2-40·3). In the hepatocellular carcinoma cohort, with a median follow-up of 19·6 months (IQR 8·7-19·8), the objective response rate was 16·7% (four of 24; 95% CI 4·7-37·4). Cadonilimab showed an encouraging tumour response rate, with a manageable safety profile, suggesting the potential of cadonilimab for the treatment of advanced solid tumours. Akeso Biopharma. For the Chinese translation of the abstract see Supplementary Materials section.

The First Cold Atmospheric Plasma Phase I Clinical Trial for the Treatment of Advanced Solid Tumors: A Novel Treatment Arm for Cancer.

Local regional recurrence (LRR) remains the primary cause of treatment failure in solid tumors despite advancements in cancer therapies. Canady Helios Cold Plasma (CHCP) is a novel Cold Atmospheric Plasma device that generates an Electromagnetic Field and Reactive Oxygen and Nitrogen Species to induce cancer cell death. In the first FDA-approved Phase I trial (March 2020-April 2021), 20 patients with stage IV or recurrent solid tumors underwent surgical resection combined with intra-operative CHCP treatment. Safety was the primary endpoint; secondary endpoints were non-LRR, survival, cancer cell death, and the preservation of surrounding healthy tissue. CHCP did not impact intraoperative physiological data (p > 0.05) or cause any related adverse events. Overall response rates at 26 months for R0 and R0 with microscopic positive margin (R0-MPM) patients were 69% (95% CI, 19-40%) and 100% (95% CI, 100-100.0%), respectively. Survival rates for R0 (n = 7), R0-MPM (n = 5), R1 (n = 6), and R2 (n = 2) patients at 28 months were 86%, 40%, 67%, and 0%, respectively. The cumulative overall survival rate was 24% at 31 months (n = 20, 95% CI, 5.3-100.0). CHCP treatment combined with surgery is safe, selective towards cancer, and demonstrates exceptional LRR control in R0 and R0-MPM patients. (Clinical Trials identifier: NCT04267575).

An exploratory trial of a novel R-ISV-RO technique in the treatment of advanced solid tumors.

e14666 Background: The immunotherapy of bone and soft tissue sarcomas remains a challenge. Our pre-clinical trial confirmed that the combination of Toll-like receptor 7 (TLR7) agonist imiquimod (R837) and OX-40 agonist had prominent synergistic effects. Immunoradiotherapy, especially Stereotactic Body Radiotherapy (SBRT) could further activate specific immune response. We hypothesized that intratumoral injection of “RO” (R837+αOX40) combined with SBRT will realize tumor control and reduce adverse reactions. Meanwhile, the synergetic application of PD-1 mAb systematically will improve the effectiveness of immunotherapy. Methods: This is a single-arm, single-center, open-label, exploratory trial that explore intratumoral injection of an emulsion of “RO” in combination with SBRT as “in situ vaccination” for advanced solid tumor (Ethics number: 2021-133-02). The inclusion criteria included: 1) advanced solid tumors which progress after standard therapies, 2) presence of one or more injectable lesions. SBRT to injected lesions was at a dose of 5-8Gy per fraction at a total dose of 20-32Gy. Imiquimod (0.75mg/ml) and αOX40 (2.5mg/ml) were prepared as emulsion and intratumoral injected into the target lesion for 4 times. Patients were also systematically administrated with PD-1 mAb (serplulimab). The primary endpoint was objective response rate (ORR) of target lesions. The secondary endpoint mainly included disease control rate (DCR) of target lesions, progression free survival (PFS), overall survival (OS), and clinical benefit rate (CBR), etc. Results: From May 2021 to October 2022, 30 patients were eligible for this trial (60% were sarcomas). 46.7% and 33.3% had received radiotherapy or PD-1/PD-L1 mAb respectively before. The ORR, DCR and CBR of target lesions were 29.2%, 91.7% and 41.7%, while these of systemic efficacy were 21.7%, 82.6% and 17.4%, respectively. In sarcomas, the ORR, DCR and CBR of target lesions were 25.0%, 93.8% and 50.0%, while these of systemic efficacy were 20.0%, 93.3% and 26.7%, respectively. Systemic median PFS were 3.67 months. The median event-free survival (EFS) of target lesions and median OS were not reached. Among the evaluable target lesions, 6-month EFS was 85.7% in sarcomas (6/7) and 76.9% in all patients (10/13). The most common TRAEs were leukopenia (50%), hypoproteinemia (30%) and anemia (20%), demonstrating that treatment is tolerable. Grade≥3 treatment-related adverse events (TRAE) occurred in 3 patients, including myocarditis (6.7%) and thyroiditis (3.3%). Conclusions: In situ vaccination with “RO” emulsion, along with SBRT was tolerable and induced anti-tumor immunity, which would also trigger systemic response when synergized with PD-1 mAb. This in situ vaccination has been proved to be a promising option for advanced solid tumors especially for sarcomas. Clinical trial information: ChiCTR2100053870 .

The first cold atmospheric plasma phase I clinical trial for the treatment of advanced solid tumors: A novel 4th treatment arm for cancer.

e14596 Background: Local recurrence contributes to the poor prognosis for patients with Stage IV metastatic or recurrent solid tumors, despite advances in standard care. We report the clinical outcome of intra-operative Cold Atmospheric Plasma (CAP) combined with standard surgical procedures. Methods: The trial was a Phase I, multi-center, open-label, prospective, controlled study. Eligible patients undergoing surgery for advanced Stage IV metastatic or recurrent solid tumors were enrolled and preoperative treatments (neoadjuvant chemotherapy, immunotherapy, radiation, and primary surgery) were permitted. Participants were recruited from Rush University Medical Center in Chicago, Illinois and Sheba Medical Center in Tel HaShomer, Israel. Twenty patients (age 26-85 years) between March 2020 to April 2021 received intra-operative CAP treatment following surgical macroscopic tumor removal. The primary endpoint was safety, and the secondary endpoint was ablation of the local microscopic tumor bed without damaging the surrounding normal tissue. Results: Physiological data (blood pressure, pulse, body temperature, End Tidal CO2, and oxygen saturation) was recorded continuously throughout surgery. There were no significant changes (p > 0.05) during intra-operative CAP treatment. One adverse event grade 3 or higher was reported but no adverse events were related to CAP. As of February 13, 2023, 10 patients died of their disease between 3-32 months. Kaplan-Meier overall survival curves show the interim 31-month rate is 24% (95% confidence interval [CI], 5.0 – 100.0%). Median survival is 23 months. For R0 patients, the Kaplan Meier local non-recurrence probability showed that the interim 28-month rate is 75% (n=8; 95% CI, 50.3 – 100.0%) as of February 13, 2023. Histological staining, TUNEL assay, and confocal imaging of the surgical margins revealed cancer cell death and no damage to the surrounding normal tissue. Primary culture of the tumor confirmed total cessation of cancer cell survival. Conclusions: CAP treatment in combination with surgery for high-risk stage IV solid tumors is safe and induces cancer cell death at the surgical bed without damaging non-cancerous tissue. The survival rate in R0-resected CAP-treated patients was significantly improved compared to R1 and R2 patients and local non-recurrence rate for R0 patients was noteworthy. Clinical trial information: NCT04267575 . [Table: see text]

A phase 1 study to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics and immunogenicity of LB4330, a peptide fused to CLDN18.2 antibody targeting the tumor antigen associated CD8+t CELLS in patients with advanced solid tumors.

TPS4196 Background: PD-1/PD-L1-targeted immunotherapies have become critical roles in the treatment for many tumors. However, there is limited progress in pancreatic ductal adenocarcinoma (PDAC). PDAC is low immunogenicity. PDAC microenvironment is immunosuppressive. More than 70% PDACs have few or no CD8+ T cells around the tumor cell or in the tumor microenvironment (TME). Therefore, immunotherapy like PD-1/PD-L1 antibody alone is rarely effective for PDACs. Some cytokine or analogs may activate CD8+ T cells. An analog specifically activating tumor antigen associated (TAA) CD8+ T cells was designed and fused to anti-CLDN18.2 antibody. This specific bi-functional molecule LB4330 has high affinity to human anti-CLDN18.2 (14pM) and CD8+T cells. LB4330, as a novel, first-in-class molecule, may activate TAA CD8+ T cells in TME and has potential in alone or in combination with PD-1/PD-L1 mAb, for the treatment of advanced solid tumors, especially for Claudin 18.2 positive PDAC. Methods: This is a FIH, phase 1 study to evaluate the safety, tolerability, pharmacokinetics and immunogenicity of LB4330 in patients with advanced solid tumors (MEETCD8-001). The planned sample size is approximately 66 patients in two parts: part 1 dose escalation, will evaluate safety, tolerability, pharmacokinetics (PK), pharmacodynamics, and determine the maximum tolerated dose (MTD) and/or the recommended phase 2 dose (RP2D). Part 2 dose expansion will further characterize the safety profile and preliminary tumor response in advanced gastric and gastroesophageal junction adenocarcinoma and PDAC with Claudin 18.2 expression. In dose escalation stage, patients will be recruited with advanced solid tumors who have failed standard treatment, or for whom standard treatment is not available or applicable at this stage. Exclusion criteria include a greater risk for gastric bleeding, irritable bowel syndrome with symptoms, active virus infections. The primary endpoints are incidence of dose limiting toxicities and adverse events, MTD, and recommended phase 2 dose. Secondary objectives will evaluate PK parameters, preliminary antitumor activity, and immunogenicity of LB4330. Tumor response will be assessed per RECIST and iRECIST every 2 cycles. The Phase I study in advanced solid tumors is ongoing. Enrollment in cohort 1 began in Nov 2022. Clinical trial information: NCT05707676 .

Efficacy and safety of surufatinib in the treatment of advanced solid tumors: a systematic evaluation and meta‑analysis.

Previous retrospective studies have suggested that surufatinib is effective for treating advanced solid tumors; however, the efficacy and safety of this drug needs to be investigated further via high-quality evidence or randomized controlled trials. In the present study, a meta-analysis was carried out to evaluate the safety and effectiveness of surufatinib for patients with advanced solid tumors. Systematic, electronic literature searches were conducted using PubMed, EMBASE, Cochrane Library and ClinicalTrials.gov. The disease control rate (DCR) of surufatinib in solid tumors was 86% [effect size (ES), 0.86; 95% confidence interval (CI), 0.82-0.90; I2=34%; P=0.208] and the objective response rate was 16% (ES, 0.16; 95% CI, 0.12-0.21; I2=48%; P=0.103), while the progressive disease rate was only 9% (ES, 0.09; 95% CI, 0.05-0.15; I2=68%, P=0.014). Surufatinib showed different degrees of adverse reactions during the treatment of solid tumors. Among these adverse events, the incidence of increased levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were 24% (ES, 0.24; 95% CI, 0.18-0.30; I2=45.1%; P=0.141) and 33% (ES, 0.33; 95%CI, 0.28-0.38; I2=63.9%; P=0.040), respectively. In the placebo-controlled trial, the relative risks (RRs) of elevated AST and ALT were 1.04 (95% CI, 0.54-2.02; I2=73.3%; P=0.053) and 0.84 (95% CI, 0.57-1.23; I2=0%; P=0.886), respectively. Overall, surufatinib was characterized by a high DCR and a low disease progression rate, thus indicating that it could exert a good therapeutic effect on solid tumors. Additionally, surufatinib showed a lower RR for adverse effects compared with other treatment modalities.

Intact regulation of G1/S transition renders esophageal squamous cell carcinoma sensitive to PI3Kα inhibitors

Phosphatidylinositol 3-kinase alpha (PI3Kα) inhibitors are currently evaluated for the therapy of esophageal squamous cell carcinoma (ESCC). It is of great importance to identify potential biomarkers to predict or monitor the efficacy of PI3Kα inhibitors in an aim to improve the clinical responsive rate in ESCC. Here, ESCC PDXs with CCND1 amplification were found to be more sensitive to CYH33, a novel PI3Kα-selective inhibitor currently in clinical trials for the treatment of advanced solid tumors including ESCC. Elevated level of cyclin D1, p21 and Rb was found in CYH33-sensitive ESCC cells compared to those in resistant cells. CYH33 significantly arrested sensitive cells but not resistant cells at G1 phase, which was associated with accumulation of p21 and suppression of Rb phosphorylation by CDK4/6 and CDK2. Hypo-phosphorylation of Rb attenuated the transcriptional activation of SKP2 by E2F1, which in turn hindered SKP2-mediated degradation of p21 and reinforced accumulation of p21. Moreover, CDK4/6 inhibitors sensitized resistant ESCC cells and PDXs to CYH33. These findings provided mechanistic rationale to evaluate PI3Kα inhibitors in ESCC patients harboring amplified CCND1 and the combined regimen with CDK4/6 inhibitors in ESCC with proficient Rb.

Abstract 685: Engineering semi-allogeneic whole cancer vaccines with enhanced immunogenicity for the treatment of advanced solid tumors

Abstract Background: Therapeutic cancer vaccines are designed to program a patient’s own immune system to recognize and eliminate tumor cells. We sought to harness gene-modified tumor cells as a vaccine platform and developed cancer vaccines composed of breast cancer cells expressing GM-CSF (SV-BR-1-GM). We have recently reported favorable clinical outcomes in patient populations that match SV-BR-1-GM at one or more HLA alleles. Mechanistically, SV-BR-1-GM cells can directly activate CD4+ T-cells in an antigen-specific HLA-restricted manner, as demonstrated by an in vitro antigen presentation assay (1). All these observations led us to hypothesize that semi-allogeneic cell-based cancer vaccines (partially matching host HLA genotype) would mount an enhanced immune response by forcing the host immune response to recognize tumor-associated antigens in the context of allogeneic HLA-I or II molecules or in proximity of strong non-self-antigens. Therefore, steps were taken to generate semi-allogeneic cancer cell lines expressing an extended repertoire of stimulatory molecules to induce optimal immune activation (Bria-OTS). Methods: SV-BR-1 (Breast cancer), PC-3 (prostate cancer), SK-MEL-24 (Melanoma), and NCI-H2228 (Lung cancer) were selected for vaccine development. To generate semi-allogeneic cell lines matching >99% of the population at least at 1 HLA allele, four cell lines (for each parental tumor cell line) were developed, each carrying two (2) HLA-A and two (2) HLA-DRB3/4/5 alleles, for a total of eight HLA-A and seven HLA-DRB3/4/5 alleles. We transduced selected co-stimulatory molecules and immune-modulatory cytokines. Next, the unique combinations of HLA-A and HLA-DRB3/4/5 alleles were transduced into the cells using lentiviral based vectors. Finally, functionality of the engineered cells was validated by using molecular and cellular based assays. Preliminary data: Four cell lines (for each tumor type) that secreted GM-CSF, IFNα, IL12, IL7 and expressed CD80, CD86, 4-1BBL, and different combinations of both Class I and Class II HLA alleles were selected. Using cell-based assays - including mixed lymphocyte reaction assays -, we demonstrated that the generated cells stimulate naïve T-cells. Evaluation of the cells ability to present antigens in an HLA-restricted antigen-specific manner is also planned. Discussion and conclusions: Different types of cancer vaccines have been developed with moderate success, often hampered by lack of strong immunogenicity and complex manufacturing. BriaCell’s Bria OTS provides a solution by increasing vaccine immunogenicity and decreasing manufacturing costs while personalizing the therapy based on matching the patient’s HLA type.1.Lacher MD et al, Front Immunol. 2018 May 15;9:776 Citation Format: Miguel A. Lopez-Lago, Vikas Bhardwaj, Xiaoyi Zheng, Sagarika pachhal, Renee Cortez, Charles Wiseman, William Williams. Engineering semi-allogeneic whole cancer vaccines with enhanced immunogenicity for the treatment of advanced solid tumors [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 685.

Abstract 1664: Discovery of a novel and potent TACC3 protein-protein interaction inhibitor targeting highly aggressive cancers

Abstract TACC3 is one of the most oncogenic members of the Transforming Acidic Coiled-Coil Containing (TACC) protein family highly overexpressed in multiple different cancers leading to worse prognosis. TACC3 is a key player in microtubule and centrosomal processes and is considered to have an important role in causing chromosomal instability leading to aggressive cancers. TACC3 also plays important role in DNA damage response mechanisms, hematopoiesis, epigenetics and immune functions by interacting with different protein partners. Inhibition of TACC3 by genomic approaches has shown significant reduction in growth of cancer cells in vitro and in vivo. Given its multiple roles in cancer, TACC3 is an ideal therapeutic target for highly aggressive cancers. Here, using phenotypic screening and rational drug design, we developed AO-252, a novel small molecule TACC3 protein-protein interaction (PPI) inhibitor. Binding assays and kinome screening suggested the specificity of AO-252 to TACC3. AO-252 targets the interactions of TACC3 with its known protein partners e.g., Clathrin/KIFC1, BARD1 and MBD2/HAT complexes regulating mitosis, DNA damage response and epigenetic functions. Gene expression profiling in multiple cell lines further confirmed the various TACC3 pathways affected by AO-252. AO-252 showed low nanomolar potency in >200 cell line panel covering various cancer indications and spared the normal cells. AO-252 showed excellent oral pharmacokinetics and demonstrated strong tumor growth inhibition or regression in multiple xenograft models without any safety concerns. Currently, AO-252 is prepared for IND submission for Q1 2023 and will enter clinic in the first half of 2023 for the treatment of advanced solid tumors including triple-negative breast cancer (TNBC), high-grade serous ovarian carcinoma (HGSOC), and endometrial cancer. Citation Format: Ozgur Sahin, Erden Banoglu, Chaemin Lim, Burcu Caliskan, Emmanuel Cruz, Sotirios Stergiopoulos, Sridhar Vempati. Discovery of a novel and potent TACC3 protein-protein interaction inhibitor targeting highly aggressive cancers [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 1664.

Abstract 5946: OBI-999, an anti-Globo H antibody drug conjugate, exhibits synergistic anti-tumor effect in combination with pembrolizumab

Abstract Background: Globo H (GH) is highly expressed in a variety of epithelial tumors with a limited expression in normal tissues rendering it a novel therapeutic target. OBI-999 is an antibody drug conjugate (ADC) consisting of a GH-specific monoclonal antibody conjugated with monomethyl auristatin E (MMAE) through a cathepsin B cleavable linker. MMAE is known to induce immunogenic cell death (ICD) which involves in the activation of cytotoxic T lymphocyte-driven adaptive immunity with long-term immunological memory. Aim: The aim of this study was to evaluate the synergistic effects of OBI-999 + pembrolizumab on tumor growth suppression in several xenograft tumor models. Methods: OBI-999-induced ICD was examined in vitro by the detection of damaging-associated molecular patterns (DAMPs) such as calreticulin (CRT), HMGB1, and ATP in incubated Globo H expressing cells. The synergistic effects with the combination of OBI-999 and pembrolizumab as well as the ICD-related immunity were assessed in vivo using advanced severe immunodeficient mice that were reconstituted with human peripheral blood mononuclear cells (PBMCs). Results: Incubation of OBI-999 with high GH expression cancer cell lines (HCC-1428, NCI-N87 and NCI-H526) and mid GH expression cancer cell line (SW-480) induced the release of DAMPs including CRT, HMGB1, and ATP, in a dose- and time-dependent manner, indicating that OBI-999 is capable of inducing ICD in vitro. In the high GH expression human breast cancer cell line HCC-1428 xenograft model, OBI-999+pembrolizumab exhibited significantly stronger inhibition of tumor growth compared to either OBI-999 or pembrolizumab alone. Similar synergistic effects were observed in other xenograft tumor models including gastric (NCI-N87), small cell lung (NCI-H526), and colorectal (SW-480) cancers. Analysis of tumor-infiltrating lymphocytes (TILs) in HCC-1428 humanized mice showed that OBI-999 + pembrolizumab induced populations of activated cytotoxic CD8 T-cells and mature dendritic cells. Pembrolizumab decreased PD-1 expression on CD8 and CD4 cells, and OBI-999 decreased PD-L1 expression on tumor cells, which reversed the exhausted status of immune cells and alleviated immunosuppression in the tumor microenvironment. Conclusion: We demonstrated significant synergistic effects of OBI-999 and pembrolizumab in several animal models. These synergistic effects may be attributed to the ability of OBI-999 to induce ICD, as demonstrated by the release of DAMPs in vitro and tumor-specific immunity in vivo, suggesting that OBI-999 can create a tumor microenvironment that enhances the function of pembrolizumab. The results suggest that combination therapy with OBI-999 and immune checkpoint inhibitors is warranted in human clinical studies. OBI-999 is currently in Phase 1/2 clinical trials for the treatment of advanced solid tumors with high GH expression (NCT04084366). Citation Format: Chun-Chung Wang, Chi-Huan Lu, Jhih-Jie Yang, Wan-Fen Li, Ming-Tain Lai. OBI-999, an anti-Globo H antibody drug conjugate, exhibits synergistic anti-tumor effect in combination with pembrolizumab [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 5946.

Population pharmacokinetic analysis of TQ-B3203 following intravenous administration of TQ-B3203 liposome injection in Chinese patients with advanced solid tumors.

Background: TQ-B3203 is a novel topoisomerase I inhibitor currently in development for the treatment of advanced solid tumors. Great differences in pharmacokinetic characteristics were found among individuals according to the phase I clinical trial following intravenous administration of TQ-B3203 liposome injection (TLI) in Chinese patients with advanced solid tumors. Thus, it is significant to establish a population pharmacokinetic model to find the key factors and recognize their effect on pharmacokinetic parameters in order to guide individualized administration. Methods: Non-linear mixed effect models were developed using the plasma concentrations obtained from the phase I clinical trial by implementing the Phoenix NLME program. Covariates that may be related to pharmacokinetics were screened using stepwise methods. The final model was validated by goodness-of-fit plots, visual predictive check, non-parametric bootstrap and a test of normalized prediction distribution errors. Results: A three-compartment model with first-order elimination was selected as the best structural model to describe TQ-B3203 disposition adequately. Direct bilirubin (DBIL) and body mass index (BMI) were the two most influential factors on clearance, while lean body weight (LBW) was considered to affect the apparent distribution volume of the central compartment. The population estimations of clearance and central volume were typical at 3.97L/h and 4.81 L, respectively. Model-based simulations indicated that LBW had a great impact on Cmax, BMI exerted a considerable influence on AUC0-t, and the significance of DBIL on both AUC0-t and Cmax was similarly excellent. Conclusion: The first robust population pharmacokinetic model of TQ-B3203 was successfully generated following intravenous administration of TLI in Chinese patients with advanced solid tumors. BMI, LBW and DBIL were significant covariates that affected the pharmacokinetics of TQ-B3203. This model could provide references for the dose regimen in the future study of TLI.

Oral formulation of bendamustine hydrochloride for patients with advanced solid tumors; a phase 1 study

SummaryTo determine the maximum tolerated dose (MTD) and recommended dose (RD) of orally-administered bendamustine in Japanese patients with advanced solid tumors. The optimal dosing schedule, safety, pharmacokinetics, and preliminary antitumor effects were also evaluated. A multicenter, open-label trial with a standard 3 + 3 design and dose escalation by dose-limiting toxicity (DLT) was conducted. The treatment schedules were once daily for 7, 14, and 21 days every 3 weeks as one cycle. The total dose per cycle was increased from 175 to 840 mg/m2. Eighteen patients were enrolled in this study. DLT occurred in one of six patients at 75 mg/m2/day × 7 days, and one of three patients at 37.5 mg/m2/day × 14 days and 25 mg/m2/day × 21 days. However, the delayed recovery from a decrease in neutrophil or platelet count hampered the start of subsequent treatment cycles, and the trend was more prominent at 37.5 mg/m2/day × 14 days and 25 mg/m2/day × 21 days than in 75 mg/m2/day × 7 days. MTD was determined as 75 mg/m2/day × 7 days to allow acceptable hematologic recovery. The pharmacokinetics of orally-administered bendamustine were generally dose-dependent; however, the inter-individual variability is relatively large. The major adverse events were hematologic toxicities; gastrointestinal disorders were generally mild. Adverse drug reactions did not lead to the discontinuation of the drug. A partial response was observed in two of six patients (prostatic small cell carcinoma and thymic carcinoma) at 75 mg/m2/day × 7 days. The RD and optimal dosing schedule of orally-administered bendamustine was 75 mg/m2 once daily for 7 days every 3 weeks for the treatment of advanced solid tumors. (Trial registration number ClinicalTrials.gov NCT03604679. Registration date July 27, 2018).