anti-OX40 Antibody Research Articles

An anti-OX40 antibody to treat moderate-to-severe atopic dermatitis: a multicentre, double-blind, placebo-controlled phase 2b study

OX40 is crucial for T-cell differentiation and memory induction. The anti-OX40 antibody, rocatinlimab inhibits the OX40 pathway. We evaluated the efficacy and safety of rocatinlimab in adults with moderate-to-severe atopic dermatitis. This multicentre, double-blind, placebo-controlled phase 2b study was done at 65 secondary and tertiary sites in the USA, Canada, Japan, and Germany. Eligible patients were adults (aged 18 years or older) with confirmed atopic dermatitis (American Academy of Dermatology Consensus Criteria or local diagnostic criteria) with moderate-to-severe disease activity, as defined by an Eczema Area and Severity Index (EASI) score of 16 or more, validated Investigator's Global Assessment for Atopic Dermatitis score of 3 (moderate) or 4 (severe), and affected body surface area 10% or higher at both screening and baseline, with documented history (within 1 year) of inadequate response to topical medications or if topical treatments were medically inadvisable. Patients were randomly assigned (1:1:1:1:1) to receive subcutaneous rocatinlimab every 4 weeks (150 mg or 600 mg) or every 2 weeks (300 mg or 600 mg) or subcutaneous placebo up to week 18, with an 18-week active-treatment extension and 20-week follow-up. Percentage change from baseline in EASI score was assessed as the primary endpoint at week 16 and during the active extension and follow-up in all randomly assigned patients exposed to study drug with a post-baseline EASI score at week 16 or earlier according to the group they were randomly assigned to. Safety was assessed in all randomly assigned patients exposed to study drug; patients were analysed according to the group they were randomly assigned to. The study is registered with ClinicalTrials.gov, NCT03703102. Between Oct 22, 2018, and Oct 21, 2019, 274 patients (114 [42%] women, 160 [58%] men; mean age 38·0 years [SD 14·5]) were randomly assigned to one of the rocatinlimab groups (217 [79%] patients) or to the placebo group (57 [21%] patients). Compared with placebo (-15·0 [95% CI -28·6 to -1·4]), significant least-squares mean percent reductions in EASI score at week 16 were observed in all rocatinlimab groups (rocatinlimab 150 mg every 4 weeks -48·3 [-62·2 to -34·0], p=0·0003; rocatinlimab 600 mg every 4 weeks -49·7 [-64·3 to -35·2], p=0·0002; rocatinlimab 300 mg every 2 weeks -61·1 [-75·2 to -47·0], p<0·0001; and rocatinlimab 600 mg every 2 weeks -57·4 [-71·3 to -43·4], p<0·0001). The most common adverse events during the double-blind period in patients receiving rocatinlimab (adverse events ≥5% of patients in the total rocatinlimab group and more common than the placebo group) were pyrexia (36 [17%] patients), nasopharyngitis (30 [14%] patients), chills (24 [11%] patients), headache (19 [9%] patients), aphthous ulcer (15 [7%] patients), and nausea (13 [6%] patients). There were no deaths. Patients treated with rocatinlimab had progressive improvements in atopic dermatitis, which was maintained in most patients after treatment discontinuation. Treatment was well tolerated. Kyowa Kirin.

OX40-OX40L Inhibition for the Treatment of Atopic Dermatitis-Focus on Rocatinlimab and Amlitelimab.

Despite the recent emergence of targeted therapeutic options, there are still unmet needs concerning moderate-to-severe atopic dermatitis treatment. This review aims to discuss the OX40-OX40L pathway as a therapeutic target for the treatment of atopic dermatitis. OX40 and OX40L are two checkpoint molecules that bind to potentiate pro-inflammatory T-cell responses that are pivotal to atopic dermatitis pathogenesis. Two OX40-OX40L inhibitors, rocatinlimab and amlitelimab, are being developed for the treatment of atopic dermatitis. Rocatinlimab, an anti-OX40 antibody, was evaluated in phase 2b, a randomized, placebo-controlled clinical trial. At week 16, rocatinlimab groups achieved a greater reduction in the EASI percentage change from the baseline (-48.3% to -61.1%) against the placebo (-15.0%; p &lt; 0.001), and clinical response was maintained 20 weeks after the treatment had ceased. Amlitelimab, an anti-OX40L antibody, was studied in a 12-week treatment phase 2a clinical trial, with a significant efficacy response observed within 2 weeks. At week 16, amlitelimab groups reached the EASI mean percentage change from the baseline of -69.9% and -80.1% versus the placebo (-49.4%; p = 0.072 and p = 0.009). Among the responders, 68% of amlitelimab patients were sustained 24 weeks following the last dose. Both treatments were shown to be safe and well tolerated. Current evidence points to OX40-OX40L inhibitors as future options for atopic dermatitis treatment with potential disease-modifying effects.

First-in-human phase I/II, open-label study of the anti-OX40 agonist INCAGN01949 in patients with advanced solid tumors

BackgroundOX40 is a costimulatory receptor upregulated on antigen-activated T cells and constitutively expressed on regulatory T cells (Tregs). INCAGN01949, a fully human immunoglobulin G1κ anti-OX40 agonist monoclonal antibody, was designed...

Structural Basis of a Novel Agonistic Anti-OX40 Antibody.

Agonistic antibodies targeting co-stimulating receptor OX40 on T cells are considered as important as (or complementary to) the immune checkpoint blockers in cancer treatment. However, none of these agonistic antibodies have reached the late stage of clinical development partially due to the lack of intrinsic potency with the correlation between binding epitope and activity of the antibody not well understood. Here, we identified a novel anti-OX40 agonistic antibody DF004, which stimulated the proliferation of human CD4+ T cells in vitro and inhibited tumor growth in a mouse model. Our crystallography structural studies showed that DF004 binds to the CRD2 region of OX40 while RG7888, an OX40 agonist antibody developed by Roche, binds to CRD3 of OX40 to the diametrically opposite position of DF004. This suggests that the agonistic activities of the antibodies are not necessarily epitope dependent. As their agonistic activities critically depend on clustering or cross-linking, our structural modeling indicates that the agonistic activity requires the optimal positioning of three Fc receptor/antibody/OX40 complexes on the cell membrane to facilitate the formation of one intracellular hexameric TRAF complex for downstream signal transduction, which is relatively inefficient. This may explain the lack of sufficient potency of these OX40 antibodies in a therapeutic setting and sheds light on the development of cross-linking-independent agonistic antibodies.

Effects of the combination of a monoclonal agonistic mouse anti-OX40 antibody and toll-like receptor agonists: Unmethylated CpG and LPS on an MB49 bladder cancer cell line in a mouse model

PurposeThe basis of the antitumor immunotherapy, of which the purpose is the stimulation of the immune system. We have used two of the Pathogen Associated Molecular Patterns: unmethylated CpG oligonucleotide, a ligand of Toll-like receptor 9 (TLR9), and lipopolysaccharide (LPS) which is recognized by TLR4, combined with an agonistic OX40 receptor-specific monoclonal antibody (anti-OX40), which is expressed by activated regulatory T-cells (and by other activated T-cell populations as well). The objective of this study was to prove the effectiveness of the aforementioned compounds in an animal model, on a bladder cancer cell line.MethodsWe have instilled MB49 cells subcutaneously, to the left musculus biceps femoris. We have created three observation groups, each containing ten mice. After eleven days, all treated mice bearing the size of 5–8 mm (in diameter) tumor were administered CpG + anti-OX40 or LPS + anti-OX40 three times with a three-day lap between each treatment. Mice in the control group did not receive any treatment.ResultsAll the specimens from the control and LPS + anti-OX40 groups have died by the sixtieth day of the observation period, however, five mice from the CpG + anti-OX40 group were still alive. The experiment lasted until the last surviving mouse died, which occurred on the 357th day after tumor implantation.DiscussionThe treatment with LPS did not make anti-OX40 more potent and did not increase the survival times. However, CpG + anti-OX40 has shown increased antitumor activity compared to the other two groups.

Abstract LB220: The anticalin-antibody bispecific PRS-352/S095025 strongly stimulates human CD4+ T cells in a PD-L1-dependent manner

Abstract Background: OX40, a member of the tumor necrosis factor receptor superfamily, is a costimulatory molecule promoting survival and cytokine release by effector T cells and inhibiting human regulatory T-cell activity. OX40 activation has been explored as a potential treatment for solid malignancies, using mainly agonistic anti-OX40 antibodies. These antibodies rely on Fc gamma receptor (FcγR)-mediated crosslinking to activate the OX40 pathway and have shown so far only limited antitumoral efficacy in clinical settings. One underlying hypothesis is that FcγR crosslinking of these antibodies may not allow optimal activation of the OX40 pathway to fully exploit the potential of this target for immunotherapy of cancer. To overcome this limitation, we designed PRS-352/S095025, a strong PD-L1-dependent OX40 agonistic bispecific molecule, that allows combination of OX40 costimulation and PD-L1 blockade. Methods: We generated an Anticalin protein that binds with high affinity to human OX40. Anticalin® proteins are approximately 18-20 kDa protein therapeutics derived from human lipocalins that can be engineered to bind with high affinity and specificity to different targets. The PRS-352/S095025 bispecific fusion protein was obtained by genetic fusion of OX40-targeting Anticalin protein to a PD-L1-targeting monoclonal antibody with a modified IgG4 backbone, allowing an optimal activation of OX40 in the presence of PD-L1, but not FcγRs. Results: We showed that PRS-352/S095025 retains binding to PD-L1 like the anti PD-L1 antibody backbone alone and binds with high affinity to both human and cynomolgus OX40. We showed that PRS-352/S095025 inhibited the PD-1/PD-L1 pathway, as the parental PD-L1 targeting antibody and an approved anti PD-L1 antibody. In addition to its PD-L1 blocking properties, we showed that PRS-352/S095025 activates OX40, and that this activity is dependent on the expression of PD-L1 and not on FcγR, consistent with the desired mechanism of action. Furthermore, we demonstrated that PRS-352/S095025 activity is superior to both PD-L1 benchmark antibodies and to the combination of clinically relevant OX40 and PD-L1 benchmark antibodies. We could also show that PRS352/S095025 strongly stimulated human CD4 T cells. In vivo, we showed that PRS-352/S095025 has a PK profile similar to that of the PD-L1 antibody alone. Conclusions: We provide here the preclinical characterization of the fusion protein PRS-352/S095025, a bispecific molecule composed of a PD-L1 blocking moiety and an Anticalin protein agonizing OX40. In vitro, this molecule showed the desired MoA, PD-L1 blocking and potent OX40 agonism driven by binding to PD-L1, with superior activity to a clinical stage OX40 agonist. Citation Format: Lucia Pattarini, Marina Pavlidou, Aizea Kastresana Morales, Janet Peper-Gabriel, Matthieu Riviere, Didier Demarles, Alix Scholer-Dahirel, Veronique Blanc, Shane Olwill. The anticalin-antibody bispecific PRS-352/S095025 strongly stimulates human CD4+ T cells in a PD-L1-dependent manner [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 LB220.

In Situ Reprogramming of Tumors for Activating the OX40/OX40 Ligand Checkpoint Pathway and Boosting Antitumor Immunity.

OX40 (CD134, TNFRSF4) is a member of the tumor necrosis factor receptor superfamily that can be activated by its cognate ligand OX40L (CD252, TNFSF4) and functions as a pair of T cell costimulatory molecules. The interaction between OX40 and OX40L (OX40/OX40L) plays a critical role in regulating antitumor immunity, including promoting effector T cells expansion and survival, blocking natural regulatory T cells (Treg) activity, and antagonizing inducible Treg generation. However, current OX40 agonists including anti-OX40 monoclonal antibodies (aOX40) have serious side effects after systemic administration, which limits their clinical success and application. Herein, we propose a strategy to reprogram tumor cells into OX40L-expressing "artificial" antigen-presenting cells (APCs) by OX40L plasmid-loaded nanoparticles for boosting antitumor immunity in situ. A novel gene transfection carrier was prepared by a modular hierarchical assembly method, which could efficiently transfect various tumor cells and express OX40L proteins on their surface. These surface-decorated OX40L proteins were proved to stimulate T cell proliferation in vitro while stimulating strong antitumor immune responses in vivo. Importantly, this in situ reprogramming strategy did not induce any toxicity as observed in aOX40 treatment, thus providing a novel method for immune checkpoint stimulator application.

OX40 Expression in Eosinophils Aggravates OVA-Induced Eosinophilic Gastroenteritis.

Background & AimsEosinophils are the main inflammatory effector cells that damage gastrointestinal tissue in eosinophilic gastrointestinal diseases (EGIDs). Activation of the OX40 pathway aggravates allergic diseases, such as asthma, but it is not clear whether OX40 is expressed in eosinophils to regulate inflammation in EGIDs. In this study, we assessed the expression and effect of OX40 on eosinophils in WT and Ox40-/- eosinophilic gastroenteritis (EGE) mice.MethodsEosinophil infiltration, ovalbumin (OVA)-specific Ig production, OX40 expression and inflammatory factor levels in the intestine and bone marrow (BM) were investigated to evaluate inflammation.ResultsWe confirmed that OVA-challenged mice produced high levels of Ox40, Mbp, Ccl11, Il5, Il4, Il13, and Il6 mRNA and a low level of Ifng mRNA in the intestine. Increased eosinophils were observed in intestinal and lymph tissues, accompanied by significantly upregulated OX40 and Type 2 cytokine production in eosinophils of EGE mice. Ox40 deficiency ameliorated OVA-induced inflammation, eosinophil infiltration, and cytokine production in the intestine. Consistently, Ox40-/ - eosinophils exhibited decreased proliferation and proinflammatory function. The stimulation of the agonistic anti-OX40 antibody, OX86, promoted the effect of OX40 on eosinophils. The present study also showed that Ox40 deficiency dampened the Traf2/6-related NF-κB signaling pathway in eosinophils.ConclusionsOX40 may play a critical role in the progress of OVA-induced EGE by promoting the maturation and function of eosinophils via the Traf2/6-related NF-κB signaling pathway.

OX40 enhances T cell immune response to PD-1 blockade therapy in non-small cell lung cancer

Immune-checkpoint blockade is widely studied for cancer therapy. Although the co-inhibitory receptor Programmed death-1(PD-1) blockade benefits some non-small cell lung cancer (NSCLC) patients, a large portion of NSCLC patients still fail to respond to this immunotherapy, and the underlying mechanism is unclear. Thus, a synergistic therapy to enhance the effect of PD-1 is urgently needed to improve the poor outcome of NSCLC patients. Here, we demonstrated that effector memory T cells were increased and T cell response became stronger in PD-1 immunotherapy responders (n = 20) but not in non-responders (n = 10). The expression of co-stimulatory receptor OX40 was upregulated on T cells following PD-1 immunotherapy and was positively associated with the percentage of PD-1+T cells and the responsiveness of T cells. Combination treatment of antagonistic anti-PD-1 and agonistic anti-OX40 antibodies (Abs) promoted the proliferation and cytokines production of T cells from PBMCs of non-responders ex vivo. Consistently, anti-PD-1 and anti-OX40 therapy synergistically augmented T cell response in an in vivo mouse lung cancer model. Our study confirmed the antitumor effects of anti-PD-1/OX40 combination in lung cancer patients as well as in the murine lung cancer model, and the results provide a rationale for clinical trials evaluating the therapeutic effect of this combination of antibodies for NSCLC immunotherapy.

Antibody-mediated delivery of a viral MHC-I epitope into the cytosol of target tumor cells repurposes virus-specific CD8+ T cells for cancer immunotherapy

BackgroundRedirecting pre-existing virus-specific cytotoxic CD8+ T lymphocytes (CTLs) to tumors by simulating a viral infection of the tumor cells has great potential for cancer immunotherapy. However, this strategy is limited by lack of amenable method for viral antigen delivery into the cytosol of target tumors. Here, we addressed the limit by developing a CD8+T cell epitope-delivering antibody, termed a TEDbody, which was engineered to deliver a viral MHC-I epitope peptide into the cytosol of target tumor cells by fusion with a tumor-specific cytosol-penetrating antibody.MethodsTo direct human cytomegalovirus (CMV)-specific CTLs against tumors, we designed a series of TEDbodies carrying various CMV pp65 antigen-derived peptides. CMV-specific CTLs from blood of CMV-seropositive healthy donors were expanded for use in in vitro and in vivo experiments. Comprehensive cellular assays were performed to determine the presentation mechanism of TEDbody-mediated CMV peptide-MHC-I complex (CMV-pMHCI) on the surface of target tumor cells and the recognition and lysis by CMV-specific CTLs. In vivo CMV-pMHCI presentation and antitumor efficacy of TEDbody were evaluated in immunodeficient mice bearing human tumors.ResultsTEDbody delivered the fused epitope peptides into target tumor cells to be intracellularly processed and surface displayed in the form of CMV-pMHCI, leading to disguise target tumor cells as virally infected cells for recognition and lysis by CMV-specific CTLs. When systemically injected into tumor-bearing immunodeficient mice, TEDbody efficiently marked tumor cells with CMV-pMHCI to augment the proliferation and cytotoxic property of tumor-infiltrated CMV-specific CTLs, resulting in significant inhibition of the in vivo tumor growth by redirecting adoptively transferred CMV-specific CTLs. Further, combination of TEDbody with anti-OX40 agonistic antibody substantially enhanced the in vivo antitumor activity.ConclusionOur study offers an effective technology for MHC-I antigen cytosolic delivery. TEDbody may thus have utility as a therapeutic cancer vaccine to redirect pre-existing anti-viral CTLs arising from previously exposed viral infections to attack tumors.

Neoadjuvant Intratumoral Immunotherapy with TLR9 Activation and Anti-OX40 Antibody Eradicates Metastatic Cancer.

This work demonstrates the ability of neoadjuvant intratumoral immunotherapy to target local and distant metastatic disease and consequently improve survival.

Inactivated Cowpea Mosaic Virus in Combination with OX40 Agonist Primes Potent Antitumor Immunity in a Bilateral Melanoma Mouse Model.

Viral immunotherapies are being recognized in cancer treatment, with several currently approved or undergoing clinical testing. While contemporary approaches have focused on oncolytic viral therapies, our efforts center on the development of plant virus-based cancer immunotherapies. In a previous work, we demonstrated the potent efficacy of the cowpea mosaic virus (CPMV), a plant virus that does not replicate in animals, applied as an in situ vaccine. CPMV is an immunostimulatory drug candidate, and intratumoral administration remodels the tumor microenvironment leading to activation of local and systemic antitumor immunity. Efficacy has been demonstrated in multiple tumor mouse models and canine cancer patients. As wild-type CPMV is infectious toward various legumes and because shedding of infectious virus from patients may be an agricultural concern, we developed UV-inactivated CPMV (termed inCPMV) which is not infectious toward plants. We report that as a monotherapy, wild-type CPMV outperforms inCPMV in mouse models of dermal melanoma or disseminated colon cancer. Efficacy of inCPMV is less than that of CPMV and similar to that of RNA-free CPMV. Immunological investigation using knockout mice shows that inCPMV does not signal through TLR7 (toll-like receptor); structure-function studies indicate that the RNA is highly cross-linked and therefore unable to activate TLR7. Wild-type CPMV signals through TLR2, -4, and -7, whereas inCPMV more closely resembles RNA-free CPMV which signals through TLR2 and -4 only. The structural features of inCPMV explain the increased potency of wild-type CPMV through the triple pronged TLR activation. Strikingly, when inCPMV is used in combination with an anti-OX40 agonist antibody (administered systemically), exceptional efficacy was demonstrated in a bilateral B16F10 dermal melanoma model. Combination therapy, with in situ vaccination applied only into the primary tumor, controlled the progression of the secondary, untreated tumors, with 10 out of 14 animals surviving for at least 100 days post tumor challenge without development of recurrence or metastatic disease. This study highlights the potential of inCPMV as an in situ vaccine candidate and demonstrates the power of combined immunotherapy approaches. Strategic immunocombination therapies are the formula for success, and the combination of in situ vaccination strategies along with therapeutic antibodies targeting the cancer immunity cycle is a particularly powerful approach.

Biomimetic nanoparticles deliver mRNAs encoding costimulatory receptors and enhance T cell mediated cancer immunotherapy

Antibodies targeting costimulatory receptors of T cells have been developed for the activation of T cell immunity in cancer immunotherapy. However, costimulatory molecule expression is often lacking in tumor-infiltrating immune cells, which can impede antibody-mediated immunotherapy. Here, we hypothesize that delivery of costimulatory receptor mRNA to tumor-infiltrating T cells will enhance the antitumor effects of antibodies. We first design a library of biomimetic nanoparticles and find that phospholipid nanoparticles (PL1) effectively deliver costimulatory receptor mRNA (CD137 or OX40) to T cells. Then, we demonstrate that the combination of PL1-OX40 mRNA and anti-OX40 antibody exhibits significantly improved antitumor activity compared to anti-OX40 antibody alone in multiple tumor models. This treatment regimen results in a 60% complete response rate in the A20 tumor model, with these mice being resistant to rechallenge by A20 tumor cells. Additionally, the combination of PL1-OX40 mRNA and anti-OX40 antibody significantly boosts the antitumor immune response to anti-PD-1 + anti-CTLA-4 antibodies in the B16F10 tumor model. This study supports the concept of delivering mRNA encoding costimulatory receptors in combination with the corresponding agonistic antibody as a strategy to enhance cancer immunotherapy.

Roles of OX40 and OX40 Ligand in Mycosis Fungoides and Sézary Syndrome.

Mycosis fungoides (MF) and Sézary syndrome (SS), the most common types of cutaneous T-cell lymphoma (CTCL), are characterized by proliferation of mature CD4+ T-helper cells. Patients with advanced-stage MF and SS have poor prognosis, with 5-year survival rates of 52%. Although a variety of systemic therapies are currently available, there are no curative options for such patients except for stem cell transplantation, and thus the treatment of advanced MF and SS still remains challenging. Therefore, elucidation of the pathophysiology of MF/SS and development of medical treatments are desired. In this study, we focused on a molecule called OX40. We examined OX40 and OX40L expression and function using clinical samples of MF and SS and CTCL cell lines. OX40 and OX40L were co-expressed on tumor cells of MF and SS. OX40 and OX40L expression was increased and correlated with disease severity markers in MF/SS patients. Anti-OX40 antibody and anti-OX40L antibody suppressed the proliferation of CTCL cell lines both in vitro and in vivo. These results suggest that OX40–OX40L interactions could contribute to the proliferation of MF/SS tumor cells and that the disruption of OX40–OX40L interactions could become a new therapeutic strategy for the treatment of MF/SS.

Radiation Augments the Local Anti-Tumor Effect of In Situ Vaccine With CpG-Oligodeoxynucleotides and Anti-OX40 in Immunologically Cold Tumor Models.

IntroductionCombining CpG oligodeoxynucleotides with anti-OX40 agonist antibody (CpG+OX40) is able to generate an effective in situ vaccine in some tumor models, including the A20 lymphoma model. Immunologically “cold” tumors, which are typically less responsive to immunotherapy, are characterized by few tumor infiltrating lymphocytes (TILs), low mutation burden, and limited neoantigen expression. Radiation therapy (RT) can change the tumor microenvironment (TME) of an immunologically “cold” tumor. This study investigated the effect of combining RT with the in situ vaccine CpG+OX40 in immunologically “cold” tumor models.MethodsMice bearing flank tumors (A20 lymphoma, B78 melanoma or 4T1 breast cancer) were treated with combinations of local RT, CpG, and/or OX40, and response to treatment was monitored. Flow cytometry and quantitative polymerase chain reaction (qPCR) experiments were conducted to study differences in the TME, secondary lymphoid organs, and immune activation after treatment.ResultsAn in situ vaccine regimen of CpG+OX40, which was effective in the A20 model, did not significantly improve tumor response or survival in the “cold” B78 and 4T1 models, as tested here. In both models, treatment with RT prior to CpG+OX40 enabled a local response to this in situ vaccine, significantly improving the anti-tumor response and survival compared to RT alone or CpG+OX40 alone. RT increased OX40 expression on tumor infiltrating CD4+ non-regulatory T cells. RT+CpG+OX40 increased the ratio of tumor-infiltrating effector T cells to T regulatory cells and significantly increased CD4+ and CD8+ T cell activation in the tumor draining lymph node (TDLN) and spleen.ConclusionRT significantly improves the local anti-tumor effect of the in situ vaccine CpG+OX40 in immunologically “cold”, solid, murine tumor models where RT or CpG+OX40 alone fail to stimulate tumor regression.

Theoretical premises of a "three in one" therapeutic approach to treat immunogenic and nonimmunogenic cancers: a narrative review.

ObjectiveWe describe experimental and theoretical premises of a powerful cancer therapy based on the combination of three approaches. These include (I) in situ vaccination (intratumoral injections of CpG oligonucleotides and anti-OX40 antibody); (II) chronometric or metronomic low-dose cyclophosphamide (CMLD CP)-based chemotherapy; (III) cancer stem cell-eradicating therapy referred to as Karanahan (from the Sanskrit kāraṇa [“source”] + han [“to kill”]).BackgroundIn murine models, the first two approaches are particularly potent in targeting immunogenic tumors for destruction. In situ vaccination activates a fully fledged anticancer immune response via an intricate network of ligand–receptor–cytokine interactions. CMLD CP-based chemotherapy primarily targets the suppressive tumor microenvironment and activates tumor-infiltrating effectors. In contrast, Karanahan technology, being aimed at replicative machinery of tumor cells (both stem-like and committed), does not depend on tumor immunogenicity. With this technology, mice engrafted with ascites and/or solid tumors can be successfully cured. There is a significant degree of mechanistic and therapeutic overlap between these three approaches. For instance, the similarities shared between in situ vaccination and Karanahan technology include the therapeutic procedure, the cell target [antigen-presenting cells (APC) and dendritic cells (DC)], and the use of DNA-based preparations (CpG and DNAmix). Features shared between CMLD CP-based chemotherapy and Karanahan technology are the timing and the dose of the cytostatic drug administration, which lead to tumor regression.MethodsThe following keywords were used to search PubMed for the latest research reporting successful eradication of transplantable cancers in animal models that relied on approaches distinct from those used in the Karanahan technology: eradication of malignancy, cure cancer, complete tumor regression, permanently eradicating advanced mouse tumor, metronomic chemotherapy, in situ vaccination, immunotherapy, and others.ConclusionWe hypothesize, therefore, that very potent anticancer activity can be achieved once these three therapeutic modalities are combined into a single approach. This multimodal approach is theoretically curative for any type of cancer that depends on the presence of tumor-inducing cancer stem cells, provided that the active therapeutic components are efficiently delivered into the tumor and the specific biological features of a given patient’s tumor are properly addressed. We expect this multimodal approach to be primarily applicable to late-stage or terminal cancer patients who have exhausted all treatment options as well as patients with inoperable tumors.

Anti-tumour effect of in situ vaccines combined with VEGFR inhibitors in the treatment of metastatic cervical cancer

Cervical cancer is the fourth most common malignant tumor in the world, for advanced cervical cancer, more than 30% of patients continue to have tumor and relapse or metastasis after the traditional treatment (concurrent chemoradiotherapy), and the response rate of immune checkpoint inhibitor (PD-1) is less 15%, so additional approaches are required. In situ vaccine is a very promising immunotherapy strategy. In the preclinical study, the combination of CPG and anti-Ox40 antibody can completely resolve injection site tumours and distant tumours and leads to the recovery of most mice with lymphoma. However, our early exploration process found that the effect of CpG + OX40 in the treatment of advanced cervical cancer is not ideal. Hence, we explored the anti-tumor effect of CpG + OX40 combined with anti-angiogenic therapy for the first time. The results showed that the combination significantly inhibited the proliferation of primary and secondary tumor volume and prolonged the survival time of mice, compared with the control group, CD3+, CD4 + and CD8 + T cells in the combined group showed an increasing trend. In addition, in terms of metabolism, the anti-vascular effect of anlotinib can significantly reduce the blood supply and metabolic level of tumor, the expression of Ki67 and CD31 in the control group was significantly higher than that in each administration group. In conclusion, our preclinical research results showed that the combination of in situ vaccine and anti-angiogenic therapy has a good anti-tumor effect, and may potentially offer an effective treatment option for patients with advanced cervical cancer.

Photothermal-Chemotherapy Enhancing Tumor Immunotherapy by Multifunctional Metal-Organic Framework Based Drug Delivery System.

Immunotherapy holds great promise for patients undergoing tumor treatment. However, the clinical effect of immunotherapy is limited because of tumor immunogenicity and its immunosuppressive microenvironment. Herein, the metal-organic framework (MIL-100) loaded with chemotherapeutic agent mitoxantrone (MTO) was combined with photothermal-chemotherapy for enhancing immunogenic cell death. MIL-100 loaded with MTO and hyaluronic acid as nanoparticles (MMH NPs) yielded an NP with two therapeutic properties (photothermal and chemotherapy) with dual imaging modes (photoacoustic and thermal). When MMH NPs were coinjected with an anti-OX40 antibody in colorectal cancer, the highest antitumor efficacy and a robust immune effect were achieved. This work provides a novel combined therapeutic strategy, which will hold great promise in future tumor therapy.

In-Situ-Sprayed Dual-Functional Immunotherapeutic Gel for Colorectal Cancer Postsurgical Treatment.

Surgery remains the most preferred treatment options for colorectal cancer (CRC). Paradoxically, local recurrence and distant metastasis are usually accelerated postsurgery as a consequence of local and systemic immunosuppression caused by surgery. Therefore, modulating tumor postoperative immune microenvironment and activating systemic antitumor immunity are necessary supplementaries for CRC therapy. Here, an in-situ-sprayed immunotherapeutic gel loaded with anti-OX40 antibody (iSGels@aOX40) is reported for CRC postsurgical treatment. The iSGel is formed instantly after spraying with strong adhesion ability via crosslinking between tannic acid (TA) and poly(l-glutamic acid)-g-methoxy poly(ethylene glycol)/phenyl boronic acid (PLG-g-mPEG/PBA). TA not only serves as one component of the iSGel but also relieves the postsurgical immunosuppressive microenvironment by inhibiting the activity of cyclo-oxygenase-2 (COX-2). The aOX40 serves as an immune agonistic antibody and is released from the iSGel in a constant manner lasting for over 20 days. In a subcutaneous murine CRC model, the iSGels@aOX40 results in complete inhibition on tumor recurrence. In addition, the cured mice show resistance to tumor re-challenge, suggesting that immune memory effects are established after the iSGels@aOX40 treatment. In an orthotopic CRC peritoneal metastatic model, the iSGels@aOX40 also remarkably inhibits the growth of the abdominal metastatic tumors, suggesting great potential for clinical CRC therapy.

Abstract 1718: Tumor eradicated by an effective in situ vaccine based on a TLR agonist and an agonistic anti-OX40 antibody

Abstract As cancers are antigenic, numerous efforts have been devoted to harnessing the exquisite specificity of the immune system to destruct tumors over the past two decades. In this study, we have employed a practical approach called in situ vaccination without the need to previously identify and isolate antigen targets. Intratumoral injection of a TLR7 ligand R837 and an agonistic anti-OX40 antibody showed impressive synergistic anti-tumor effects. R837 upregulated the expression of OX40 on CD4+ T cells in the treated tumor. Then, anti-OX40 antibody triggered systemic tumor-specific T cell responses, with one-fold increase of effector memory T cells properties and stronger toxicity of lymphocytes in spleen. Remarkably, both the injected tumor and the noninjected tumor in the distant lesion of the mice were eliminated after vaccination. IL-1α is a pro-inflammatory cytokine, however IL-10 is an important anti-inflammatory cytokine that plays a central role as a negative immune regulator. In the tumor microenvironment, we found that the level of IL-1α increased and IL-10 decreased after vaccination. From RNA-seq analysis, many immune-related pathways in the tumor microenvironment were activated after vaccination, such as TNF signaling pathway, NOD-like receptor signaling pathway, C-type lectin receptor signaling pathway, Toll-like receptor signaling pathway and so on. This in situ vaccine based on two low doses of immunoomdulators caused little harm to normal organs and provided long-term protection against the same syngeneic tumor rechallenge. It could be applied to various types of late stage solid tumors and worthy of further clinical research. Citation Format: Yanhong Chu, Qin Liu, Baorui Liu. Tumor eradicated by an effective in situ vaccine based on a TLR agonist and an agonistic anti-OX40 antibody [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1718.