Synergistic Antitumor Effects In Combination Research Articles

Design, Synthesis, and Evaluation of (R)-8-((Tetrahydrofuran-2-yl)methyl)pyrido[2,3-d]pyrimidin-7-ones as Novel Selective ACK1 Inhibitors to Combat Acquired Resistance to the Third-Generation EGFR Inhibitor.

Activated Cdc42-associated kinase 1 (ACK1) alterations have been considered to mediate bypass acquired resistance to the third-generation EGFR inhibitors (ASK120067 and osimertinib) in NSCLC. Despite many efforts to develop ACK1 small molecule inhibitors, no selective inhibitors have entered clinical trials. We used structure-based drug design to obtain a series of (R)-8-((tetrahydrofuran-2-yl)methyl)pyrido [2,3-d]pyrimidin-7-ones as novel selective ACK1 inhibitors. One of the representative compounds, 10zi, potently inhibited ACK1 kinase with an IC50 of 2.1 nM, while sparing SRC kinase (IC50 = 218.7 nM). Further, 10zi displayed good kinome selectivity in a profiling of 468 kinases. In the ASK120067-resistant lung cancer cell line (67R), 10zi dose-dependently inhibited the phosphorylation of ACK1 and downstream AKT pathway and showed a strong synergistic anti-tumor effect in combination with ASK120067 in vitro. Additionally, 10zi also exhibited reasonable PK profiles with an oral bioavailability of 19.8% at the dose of 10 mg/kg, which provided a promising lead for further development of new anticancer drugs.

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.

Abstract 1831: A long-acting and CD122-enhanced IL-2 analog, HM16390, synergizes with immune checkpoint inhibitor by remodeling an immune cell profile in tumor microenvironment

Abstract Immune checkpoint inhibitors (CPI) are widely used for cancer immunotherapy. However, the response to CPIs is dependent on phenotype of tumor microenvironment (TME). A cold tumor known as immune-excluded or -desert has shown poor response to CPIs due to an absence of effector T cells in TME. IL-2 analog, which is immune stimulator and able to recruit cancer-fighting cells into TME, may be promising therapeutic partner for overcoming a limitation of CPIs. Previously, HM16390, a long-acting CD-122-enhanced IL-2 analog, exerted dose-dependent anti-tumor activity in low immunogenic B16F10 melanoma mice. Here, we further investigated the immune cells composition in TME following HM16390 treatment and synergistic anti-tumor effect after combination with CPI. B16F10 mice were sacrificed at days 1, 3, and 8 following single subcutaneous administration of HM16390 or 5 consecutive daily administrations of aldesleukin. According to the result, HM16390 transiently increased peripheral cytokines (IFNγ and TNFα) more than aldesleukin. In line with this, we observed that the tumor-infiltrating NK/Treg ratio was significantly increased approximately 19 by treatment of HM16390 while showing 4.2 in aldesleukin treated group at Day 3. Furthermore, tumor-infiltrating CD8+/Treg ratio was also upregulated approximately 74 by treatment of HM16390 while only showing 6.1 in aldesleukin treated group at Day 8. Significantly increased pro-inflammatory molecules such as GrzB and IFNγ were also observed in HM16390 treated group compared to aldesleukin (p<0.01 and p<0.001, respectively). Next, we investigated synergistic anti-tumor effects in combination with CPI. B16F10 mice were repeatedly given HM16390 once a week or aldesleukin 5 consecutive days per week with or without mouse anti-PD1. After four weeks treatment, 25% of B16F10 mice showed complete response by treatment of HM16390, and significantly increased up to 88% by combination with anti-PD1. However, none of the mice showed complete response by treatment of aldesleukin/anti-PD1 combo. In conclusion, HM16390 effectively induced tumor growth inhibition through the activation and tumor infiltration of cytotoxic lymphocytes. This favorable immune alteration in tumor elicited a TME remodeling in which CPI could sufficiently respond. Citation Format: Jaehyuk Choi, Jinyoung Kim, Yu Yon Kim, Seongju Jeong, Sungmin Bae, Daejin Kim, In Young Choi. A long-acting and CD122-enhanced IL-2 analog, HM16390, synergizes with immune checkpoint inhibitor by remodeling an immune cell profile in tumor microenvironment [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 1831.

PD-1/LAG-3 bispecific antibody potentiates T cell activation and increases antitumor efficacy.

Several clinical studies demonstrate that there exist other immune checkpoints overexpressed in some PD-1 inhibitor-resistant tumor patients. Among them, Lymphocyte-activation gene 3 (LAG-3) is one of the important immune checkpoint molecules and has been clinically demonstrated to have synergistic anti-tumor effects in combination with PD-1 antibody. In this study, we designed a novel 'knob-in-hole' PD-1/LAG-3 bispecific antibody (BsAb) YG-003D3. In conclusion, the BsAb maintained the similar affinity and thermal stability to the parental antibody, and the BsAb structure can be independent of each other in the process of double-target recognition, and the recognition activity will not be affected. Moreover, the BsAb can not only target PD-1 and LAG-3 on single cell simultaneously, but also bridge the two kinds of cells expressing PD-1 and LAG-3, so as to release the 'brake system of immune checkpoints' and activate immune cells to exert anti-tumor effects more effectively. Especially in the PBMCs activation assay, YG-003D3 induced stronger IFN-γ, IL-6, and TNF-α secretion compared to anti-PD-1 or anti-LAG-3 single drug group or even combined drug group. In the tumor killing experiment of PBMC in vitro, YG-003D3 has a better ability to activate PBMC to kill tumor cells than anti-PD-1 or anti-LAG-3 single drug group or even combined drug group, and the killing rate is as high as 20%. In a humanized PD-1/LAG-3 transgenic mouse subcutaneous tumor-bearing model, YG-003D3 showed good anti-tumor activity, even better than that of the combination group at the same molar concentration. Further studies have shown that YG-003D3 could significantly alter the proportion of immune cells in the tumor microenvironment. In particular, the proportion of CD45+, CD3+ T, CD8+ T cells in tumor tissue and the proportion of CD3+ T, CD8+ T, CD4+ T cells in peripheral blood were significantly increased. These results suggest that YG-003D3 exerts a potent antitumor effect by activating the body 's immune system. In summary, the BsAb YG-003D3 has good anti-tumor activity, which is expected to become a novel drug candidate for cancer immunotherapy.

Activation of Stimulation of Interferon Genes (STING) Signal and Cancer Immunotherapy.

Stimulator of interferon gene (STING), an intracellular receptor in the endoplasmic reticulum, could induce the production of cytokines such as type I interferon (IFN) by activating the cGAS-STING signal pathway. In recent years, activation of STING has shown great potential to enhance anti-tumor immunity and reshape the tumor microenvironment, which is expected to be used in tumor immunotherapy. A number of STING agonists have demonstrated promising biological activity and showed excellent synergistic anti-tumor effects in combination with other cancer therapies in preclinical studies and some clinical trials. The combination of STING agonists and ICI also showed a potent effect in improving anti-tumor immunity. In this review, we introduce the cGAS-STING signaling pathway and its effect in tumor immunity and discuss the recent strategies of activation of the STING signaling pathway and its research progress in tumor immunotherapy.

Natural killer cells have a synergistic anti-tumor effect in combination with chemoradiotherapy against head and neck cancer

BackgroundThe use of natural killer (NK) cells is a promising approach in the field of cancer immunotherapy; however, combination treatments are required to enhance the effects of NK cell immunotherapy. In this study, we assessed the potential of irradiation and cisplatin as a chemoradiotherapy (CRT) regimen to augment the effects of NK cell immunotherapy in head and neck squamous cell carcinoma (HNSCC). MethodsNK cells were expanded using our recently established K562-OX40 ligand and membrane-bound interleukin (IL)-18 and IL-21 feeder cells in the presence of IL-2/IL-15 from peripheral blood of healthy donors. ResultsThe results showed an increase in the purity of NK cells and expression of activation markers such as NKG2D and lymphocyte function–associated antigen 1 during the expansion process, which is positively correlated to the NK cell infiltration and overall survival in patients with HNSCC. CRT induced NK cell activation ligand (ULBP2) and adhesion molecules (ICAM-1, -2 and -3) on HNSCC, leading to enhanced cytotoxicity of NK cells against HNSCC. ConclusionsOur findings suggest that the NK cells have a potent anti-tumor effect in combination with CRT against HNSCC.

Abstract 6111: OBI-3424, an AKR1C3-activated prodrug, exhibits in vivo synergistic anti-tumor effect in combination with pembrolizumab by induction of immunogenic cell death

Abstract Immunogenic cell death (ICD) involves the activation of cytotoxic T lymphocyte-driven adaptive immunity with long-term immunological memory. OBI-3424 is a highly selective prodrug that is activated by AKR1C3 to release a potent bis-alkylating agent. This study aims to investigate whether OBI-3424 can induce ICD and create a tumor microenvironment that benefits the combination therapy of OBI-3424 with immune checkpoint inhibitors. OBI-3424 induced ICD was examined in vitro by incubation of the prodrug with AKR1C3 positive cells followed by the detection of damaging-associated molecular patterns (DAMPs). The ICD-related immunity was assessed in vivo using advanced severe immunodeficient mice that were engrafted with human peripheral blood mononuclear cells (PBMCs). Anti-tumor effect of OBI-3424 in combination with pembrolizumab was evaluated in a xenograft model using PBMC-humanized mice. Incubation of OBI-3424 with AKR1C3 positive cells H460 and HepG2 induced the release of DAMPs including calreticulin, HMGB1, and ATP, in dose- and time-dependent manners. The detection of the DAMPs indicated that OBI-3424 induced ICD in vitro. The OBI-3424-induced ICD and its related immunity were also assessed in vivo. PBMC-humanized mice were immunized with OBI-3424- or PBS-treated HepG2 cells and then challenged with live HepG2 cells. No tumor growth was noted in mice that were immunized with OBI-3424-treated cells, indicating that the dying HepG2 cells induced by OBI-3424 elicited an adaptive, tumor-specific immune response. Furthermore, OBI-3424 showed a synergistic anti-tumor effect in combination with pembrolizumab in HepG2 xenograft model using PBMC-humanized mice. OBI-3424 plus pembrolizumab exhibited significantly stronger inhibition on tumor growth (TGI 77.2%) when compared with the treatment of OBI-3424 (TGI 27.8%) or pembrolizumab (TGI -15.3%) alone. Analysis of tumor-infiltrating lymphocytes (TILs) showed that OBI-3424 treatment induced the populations of activated cytotoxic CD8 T-cells (CD45+/CD8+/CD69+ and CD45+/CD8+/Granzyme), activated helper CD4 T-cells (CD45+/CD4+/CD69+), and mature dendritic cells (CD11b+/CD86+). In addition, OBI-3424 treatment also increased PD-1 expression on CD8 and CD4 cells, which in turn potentiated the anti-tumor effect of pembrolizumab. We demonstrated that OBI-3424 was able to induce ICD as shown by the release of DAMPs in vitro and tumor-specific immunity in vivo. OBI-3424 also created a tumor microenvironment that enhances the function of pembrolizumab, supported by the synergistic effect in animals with the cotreatment of the two drugs. The results suggest that a combination therapy of OBI-3424 and anti-PD-1 in human clinical study is warranted. OBI-3424 is currently in Phase 1/2 clinical trials for solid tumor and acute lymphoblastic leukemia (NCT03592264 and NCT04315324). Citation Format: Chun-Chung Wang, Wan-Fen Li, Chih-Chan Lee, Lu-Tzu Chen, Jhih-Jie Yang, Jiann-Shiun Lai, Ming-Tain Lai. OBI-3424, an AKR1C3-activated prodrug, exhibits in vivo synergistic anti-tumor effect in combination with pembrolizumab by induction of immunogenic cell death [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 6111.

An Antiangiogenic Agent Associated with Multi-Targets Exhibits Synergistic Antitumor Effects in Combination with Immunotherapeutics

An Antiangiogenic Agent Associated with Multi-Targets Exhibits Synergistic Antitumor Effects in Combination with Immunotherapeutics

Repurposing macitentan with nanoparticle modulates tumor microenvironment to potentiate immune checkpoint blockade

Immune checkpoint therapy (ICT), which reinvigorates cytotoxic T cells, provides clinical benefits as an alternative to conventional cancer therapies. However, its clinical response rate is too low to treat an immune-excluded tumor, owing to the presence of abundant stromal elements impeding the penetration of immune cells. Here, we report that macitentan, a dual endothelin receptor antagonist approved by the FDA to treat pulmonary arterial hypertension, can be repositioned to modulate the desmoplastic tumor microenvironment (TME). In the 4T1 orthotopic tumor model, the polymeric nanoparticles bearing macitentan (M-NPs) prevent fibrotic progression by regulating the function of cancer-associated fibroblasts, attenuate the biogenesis of cancer cell-derived exosomes, and modulate the T cell subsets and distribution in TME. These results demonstrate that the M-NPs effectively reorganize the immunosuppressive TME by targeting the endothelin-1 axis and consequently exhibit synergistic antitumor effects in combination with ICT.

Bladder preservation therapy in combination with atezolizumab and radiation therapy for invasive bladder cancer (BPT-ART) – A study protocol for an open-label, phase II, multicenter study

Radical cystectomy (RC) is recommended for muscle-invasive bladder cancer (MIBC) or highest-risk non-muscle-invasive bladder cancer (NMIBC). Trimodal therapy (TMT) is the most favorable strategy among bladder preservation therapies (BPT) for patients who are ineligible for or refuse RC. However, referrals for TMT, especially following chemotherapy, are limited by the patient's condition. Therefore, new BPT approaches are needed. Atezolizumab inhibits programmed death-ligand 1, is well-tolerated in patient populations heavily dominated by renal insufficiency, and is expected to have synergistic anti-tumor effects in combination with radiation therapy (RT). Therefore, we have conducted this open-label phase II multicenter study to evaluate the efficacy and safety of RT in combination with atezolizumab for T2-3 MIBC and highest-risk T1 NMIBC patients. This study was initiated in January 2019, and we aimed to enroll a total of 45 patients. The study is registered in the Japan Registry of Clinical Trials (Identifier: RCT2031180060).

Anlotinib optimizes anti-tumor innate immunity to potentiate the therapeutic effect of PD-1 blockade in lung cancer.

Many anti-angiogenic agents have the potential to modulate the tumor microenvironment and improve immunotherapy. Anlotinib has demonstrated anti-tumor efficacy in non-small cell lung cancer (NSCLC) in third-line clinical trials. However, its roles in immune regulation and potentially synergistic anti-tumor effect in combination with immune checkpoint inhibition remain unclear. Here, based on a syngeneic lung cancer mouse model, the intratumoral immunological changes post-anlotinib treatment in the model were assessed. Furthermore, it was tested whether anlotinib could enhance the anti-tumor effect of αPD-1 in vivo. This study shows that anlotinib increased infiltration of the innate immune cells, including natural killer (NK) cells, and antigen-presenting cells (APC), which include M1-like tumor-associated macrophages (TAM) and dendritic cells (DC), whereas the percentage of M2-like TAM was dramatically reduced. Subsequently, when combined with PD-1/PD-L1 (programmed cell death 1/PD-1 ligand 1) blockade, anlotinib conferred significantly synergistic therapeutic benefits. Overall, these findings describe a role for anlotinib in the innate immune cells in the tumor microenvironment and a potentially synergistic anti-tumor combination with immune checkpoint inhibition.

Immunomodulation by HDAC inhibition: Results from a phase I study with entinostat in combination with atezolizumab and bevacizumab in metastatic renal cell carcinoma patients.

5064 Background: Immunosuppressive regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs) limit the efficacy of immunotherapies. We have previously reported that the HDAC inhibitor entinostat has synergistic antitumor effect in combination with immunotherapies in preclinical models by inhibiting Tregs and MDSCs function. The combination of atezolizumab (PD-L1 inhibitor) and bevacizumab (VEGF inhibitor) is active in renal cell carcinoma (RCC). Thus, we have conducted a Phase I study with entinostat, atezolizumab and bevacizumab in patients (pts) with metastatic RCC. Methods: The primary objective was to evaluate safety and tolerability. The phase I portion included 3 dose levels of entinostat (1 mg, 3 mg or 5 mg, PO weekly) and fixed, standard doses of atezolizumab (1200 mg IV every 21 days) and bevacizumab (15 mg/Kg IV every 21 days). Pts with any histological type and prior therapies were included. Results: Dose levels were completed with up to 1 DLT/dose level. 5 mg was the Phase II recommended dose for entinostat. DLTs included hypertension, encephalopathy, hyponatremia and pruritus. The most common resolved grade 3/4 toxicities were hypophosphatemia (33%), hypertension (17%), and pneumonitis (11%). We have enrolled 18 pts (17 evaluable for ORR by RECIST). 5 pts continue on treatment. 3 pts discontinued treatment because of adverse events, 9 pts for disease progression, and one pt for physician decision. Good risk and intermediate risk pts were 61% and 39%, respectively. Overall ORR was 47.1% (95% CI 23.0-72.2) and median PFS was 7.6 months (95% CI 1.6-16.3). In pts with no prior therapies (12) the ORR was 58.3% (95% CI 27.7-84.8) and median PFS was 13.4 months (95% CI 1.5-28.9). One additional PR was observed by ir-RC but was not confirmed within the data cut-off date of 11/11/19. In pts with prior immune checkpoint inhibitors (ICIs) (5) ORR was 20% (95% CI 0.5-71.6) and median PFS was 7.6 months (95% CI 1.3-NR). Preliminary data show a statistically significant lower % of circulating monocytic MDSC (HLADR−1CD11b+CD33highCD14+CD15−) and exhausted T cells (CD45+CD3+CD8+TIM3+) following treatment in pts (4) with objective responses as compared to pts (4) with progressive disease. Conclusions: The results from this phase I suggest that the combination of entinostat, atezolizumab and bevacizumab is relatively well tolerated and is active in renal cell carcinoma patients, in both ICIs naïve and resistant disease. A phase II portion of this study is currently accruing patients. Clinical trial information: NCT03024437 .

Combination of cyclophosphamide and shengbai decoction has synergistic effect against melanoma

Shengbai decoction (SBD), a famous Chinese herbal prescription, has been used for treatment of leukopenia for decades in China. In this study, its synergistic antitumor effect in combination with cyclophosphamide (CTX) on melanoma-bearing mice wasinvestigated. A total of forty C57BL/6 male mice successfully modeled (6–8 weeks old, 18−22 g) were randomly divided into 4 groups (n = 10): 1) the model group, 2) the CTX group, 3) the low dose of SBD (10.66 g/kg/d, raw medicine) and CTX group, and 4) the high dose of SBD (31.98 g/kg/d, raw medicine) and CTX group. Melanoma mice models were established by injection of 0.1 mL of melanoma cell suspension under the midline of the back of each C57BL/6 mouse. Treatment started five days after modeling. The results showed that SBD significantly alleviated histopathological damage, and reduced tumor growth and the concentrations of IL-6, IFN-γ and TNF-α in serum. Furthermore, the combined therapy increased the positive expression of NF-κB and promoted apoptosis compared with CTX alone. These results indicated that SBD could improve the antitumor effect of CTX on melanoma in vivo. And this combination treatment may be an ideal therapy against melanoma.

Randomized phase II study of valproic acid in combination with bevacizumab and oxaliplatin/fluoropyrimidine regimens in patients with RAS-mutated metastatic colorectal cancer: the REVOLUTION study protocol.

Background:Despite effective treatments, metastatic colorectal cancer (mCRC) prognosis is still poor, mostly in RAS-mutated tumors, thus suggesting the need for novel combinatorial therapies. Epigenetic alterations play an important role in initiation and progression of cancers, including CRC. Histone-deacetylase inhibitors (HDACi) have shown activity in combination with chemotherapy in the treatment of solid tumors. Owing to its HDACi activity and its safe use for epileptic disorders, valproic acid (VPA) is a good candidate for anticancer therapy that we have largely explored preclinically translating our findings in currently ongoing clinical studies. We have shown in CRC models that HDACi, including VPA, induces synergistic antitumor effects in combination with fluoropyrimidines. Furthermore, unpublished results from our group demonstrated that VPA induces differentiation and sensitization of CRC stem cells to oxaliplatin. Moreover, preclinical and clinical data suggest that HDACi may prevent/reverse anti-angiogenic resistance.Methods/Design:A randomized, open-label, two-arm, multicenter phase-II study will be performed to explore whether the addition of VPA to first line bevacizumab/oxaliplatin/fluoropyrimidine regimens (mFOLFOX-6/mOXXEL) might improve progression-free survival (PFS) in RAS-mutated mCRC patients. A sample size of 200 patients was calculated under the hypothesis that the addition of VPA to chemotherapy/bevacizumab can improve PFS from 9 to 12 months, with one-sided alpha of 0.20 and a power of 0.80. Secondary endpoints are overall survival, objective response rate, metastases resection rate, toxicity, and quality of life. Moreover, the study will explore several prognostic and predictive biomarkers on blood samples, primary tumors, and on resected metastases.Discussion:The “Revolution” study aims to improve the treatment efficacy of RAS-mutated mCRC through an attractive strategy evaluating the combination of VPA with standard cancer treatment. Correlative studies could identify novel biomarkers and could add new insight in the mechanism of interaction between VPA, fluoropyrimidine, oxaliplatin, and bevacizumab.Trial Registration:EudraCT: 2018-001414-15; ClinicalTrials.gov identifier: NCT04310176

Oral Administration of Poly-Gamma-Glutamic Acid Significantly Enhances the Antitumor Effect of HPV16 E7-Expressing Lactobacillus casei in a TC-1 Mouse Model.

The conventional prophylactic vaccines for human papillomavirus (HPV) efficiently prevent infection with high-risk HPV types, but they do not promote therapeutic effects against cervical cancer. Previously, we developed HPV16 E7-expressing Lactobacillus casei (L. casei-E7) as a therapeutic vaccine candidate for cervical cancer, which induces antitumor therapeutic effects in a TC-1 murine cancer model. To improve the therapeutic effect of L. casei-E7, we performed co-treatment with poly-gamma-glutamic acid (γ-PGA), a safe and edible biomaterial naturally secreted by Bacillus subtilis. We investigated their synergistic effect to improve antitumor efficacy in a murine cancer model. The treatment with γ-PGA did not show in vitro cytotoxicity against TC-1 tumor cells; however, an enhanced innate immune response including activation of dendritic cells was observed. Mice co-administered with γ-PGA and L. casei-E7 showed significantly suppressed growth of TC-1 tumor cells and an increased survival rate in TC-1 mouse models compared to those of mice vaccinated with L. casei-E7 alone. The administration of γ-PGA markedly enhanced the activation of natural killer (NK) cells but did not increase the E7-specific cytolytic activity of CD8+ T lymphocytes in mice vaccinated with L. casei-E7. Overall, our results suggest that oral administration of γ-PGA induces a synergistic antitumor effect in combination with L. casei-E7.

Immunomodulation by HDAC inhibition: Results from a phase Ib study with vorinostat and pembrolizumab in metastatic urothelial, renal, and prostate carcinoma patients.

2572 Background: Immunosuppressive factors such as regulatory T cells (Tregs) and myeloid-derived suppressive cells (MDSCs) limit the efficacy of immunotherapies. Histone deacetylase (HDAC) inhibitors have been shown to have immunomodulatory effects. We have previously reported that HDAC inhibitors have synergistic antitumor effects in combination with PD-1 inhibition in tumor models by inhibiting the function of Tregs and MDSCs. Thus, we conducted a Phase Ib clinical study with the HDAC inhibitor vorinostat and the PD-1 inhibitor pembrolizumab in patients (pts) with metastatic urothelial, renal and prostate carcinoma. Methods: The primary objective was to evaluate the safety and tolerability of this combination strategy. The phase I portion consisted of two dose levels of vorinostat (100 and 200 mg, PO daily 2 weeks ON and one week OFF) and a fixed, standard dose of pembrolizumab (200 mg IV every 21 days). Patients were assigned to three cohorts: Cohort A (previously treated, anti-PD1/PD-L1 naïve urothelial and renal cancer pts = 15), Cohort B (previously treated, anti-PD1/PD-L1 resistant urothelial and renal cancer pts = 14), and Cohort C (prostate cancer pts = 14). Results: Dose levels 1 (4 enrolled, 3 evaluable) and 2 (4 enrolled, 3 evaluable) were completed without DLTs and 200 mg was the Phase II recommended dose for vorinostat. The most common resolved grade 3/4 toxicities were acute kidney injury (n = 1), anemia (n = 1), diarrhea (n = 1), and hypothyroidism (n = 1) in the dose expansion cohorts. We have enrolled 43 pts (37 evaluable) in the dose expansion cohorts. For Cohort A, B, and C the median PFS were 2.8 months, 5.2 months, and 3.5 months. Two PR were observed including the dose escalation phase. Two PCA pts have achieved undetectable PSA. We have performed several correlative studies including flow cytometry and gene expression analysis on peripheral blood mononuclear cells, PDL-1 staining and PSMA PET scans in a subset of pts. Conclusions: The results from this phase Ib suggest that the combination of vorinostat and pembrolizumab is relatively well tolerated and may be active in a subset of immune checkpoint resistant UC/RCC pts and immune checkpoint naïve PCA pts. Clinical trial information: NCT02619253.

CD47-signal regulatory protein α signaling system and its application to cancer immunotherapy.

Tumor cells evade immune surveillance through direct or indirect interactions with various types of immune cell, with much recent attention being focused on modifying immune cell responses as the basis for the development of new cancer treatments. Signal regulatory protein α (SIRPα) and CD47 are both transmembrane proteins that interact with each other and constitute a cell‐cell communication system. SIRPα is particularly abundant in myeloid cells such as macrophages and dendritic cells, whereas CD47 is expressed ubiquitously and its expression level is elevated in cancer cells. Recent studies have shown that blockade of CD47‐SIRPα interaction enhances the phagocytic activity of phagocytes such as macrophages toward tumor cells in vitro as well as resulting in the efficient eradication of tumor cells in a variety of xenograft or syngeneic mouse models of cancer. Moreover, CD47 blockade has been shown to promote the stimulation of tumor‐specific cytotoxic T cells by macrophages or dendritic cells. Biological agents, such as Abs and recombinant proteins, that target human CD47 or SIRPα have been developed and are being tested in preclinical models of human cancer or in clinical trials with cancer patients. Preclinical studies have also suggested that CD47 or SIRPα blockade may have a synergistic antitumor effect in combination with immune checkpoint inhibitors that target the adaptive immune system. Targeting of the CD47‐SIRPα signaling system is thus a promising strategy for cancer treatment based on modulation of both innate and acquired immune responses to tumor cells.

[Mechanism and Prospect of Radiotherapy Combined with Apotatinib
in the Treatment of Non-small Cell Lung Cancer].

非小细胞肺癌是危害人类生命健康的最常见的恶性肿瘤之一。大多数患者确诊时为晚期，不符合手术适应症，主要的治疗方法是放化疗联合。近年来，随着抗血管生成治疗恶性肿瘤理论的提出，阿帕替尼作为一种新型的抗肿瘤药物，与放疗联合具有协同作用。可能的机制包括使血管正常化，改善肿瘤内乏氧情况，调节促血管生成因子水平等。将阿帕替尼与放疗联合有望成为一种新的治疗策略应用于非小细胞肺癌的治疗中，提高肺癌的治疗效果。

Abstract CT015: Results from a phase I/II study with the HDAC inhibitor entinostat in combination with high-dose interleukin-2 in renal cell carcinoma patients (CTEP#7870)

Abstract Background: Immunosuppressive factors such as regulatory T cells (Tregs) and myeloid-derived suppressive cells (MDSCs) limit the efficacy of immunotherapies. Histone deacetylase (HDAC) inhibitors have been shown to have immunomodulatory effects. We have previously reported that the class I selective HDAC inhibitor entinostat has synergistic antitumor effects in combination with high dose interleukin-2 (IL-2) in a renal cell carcinoma model by down-regulating Foxp3 expression and function of Tregs. Thus, we have conducted a phase I/II clinical study with entinostat and high dose IL-2 in patients (pts) with metastatic clear cell renal cell carcinoma. Methods: The primary objectives were to evaluate the safety, tolerability and efficacy of this combination strategy. The main eligibility criteria were clear cell histology, no prior treatments, and being fit to receive high dose IL-2. The phase I portion consisted of two dose levels of entinostat (3 and 5 mg, PO every14 days) and a fixed standard dose of IL-2 (600,000 units/kg IV every 8 hrs, up to 14 doses). Each cycle was 85 days. To test our hypothesis, the fixed sample size for the phase II was 36 with a type I/II error of 10%. If 11 or more of the pts have a response, the hypothesis that the response rate is ? 20% is rejected. Results: Dose levels 1 and 2 were completed without DLTs and 5 mg was the recommended phase II dose for entinostat. The most common transient grade 3/4 toxicities were hypophosphatemia (16%), lymphopenia (15%), and hypocalcemia (7%). We have enrolled a total of 47 pts (44 at dose level 2), and 37 have completed one cycle (84 days) treatment. Four pts were not evaluable and were replaced. To date, the objective response is 35% (10 PR, 3 CR), the median progression-free survival is 16.1 months (6.2,27.8) and the median overall survival is 65.3 months (52.6,65.3). Decreased Tregs have been observed following treatment and lower numbers were associated with response. Analysis of monocityc MDSCs and activated antigen presenting cells will be also reported. Conclusions: The results from this clinical trial suggest that entinostat may increase the therapeutic effect of high dose IL-2 by modulating immunosuppressive cells, and represent the first example of how epigenetic agents may be rationally combined with immunotherapies. (R21CA137649; U01CA70095) Citation Format: Roberto Pili, David I. Quinn, Hans J. Hammers, J. Paul Monk, Saby George, Tanya B. Dorff, Thomas Olencki, Li Shen, Dominick Lamonica, Alan Hutson, Adrienne Groman, Susan M. Perkins, Richard Piekarz, Michael Carducci. Results from a phase I/II study with the HDAC inhibitor entinostat in combination with high-dose interleukin-2 in renal cell carcinoma patients (CTEP#7870). [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr CT015.

Synergistic antitumor effects of combination PI3K/mTOR and MEK inhibition (SAR245409 and pimasertib) in mucinous ovarian carcinoma cells by fluorescence resonance energy transfer imaging.

The aim of this study was to clarify the synergistic effects of dual inhibition of the PI3K/mTOR and MAPK pathways in ovarian mucinous carcinoma (OMC) cells, using fluorescence resonance energy transfer (FRET) imaging. We exposed 6 OMC cell lines to a PI3K/mTOR inhibitor (voxtalisib, SAR245409) and/or a MEK inhibitor (pimasertib), and evaluated synergistic effects using the Chou–Talalay method. Then, S6K (PI3K pathway) and ERK (MAPK pathway) kinase activities, and their individual proliferative or cytotoxic effects were calculated by time-lapse FRET imaging. In combination with SAR245409, pimasertib (30 nM) synergistically inhibited cell growth (combination indexes: 0.03–0.5) and induced apoptosis in all 6 OMC cell lines. FRET-imaging results demonstrated that ERK inhibition induced both anti-proliferation and apoptosis in a dose-dependent manner in both MCAS and OAW42 cells. However, S6K inhibition suppressed proliferation in a threshold manner in both cell lines, although apoptosis was only induced in OAW42 cells. These results demonstrated that combined PI3K/mTOR and MEK inhibition exhibited synergistic antitumor effects in OMC cells and that FRET imaging is useful for analyzing kinase activities in live cells and elucidating their cytostatic and cytotoxic effects.