Anti-CTLA-4 antibody self-presented dendritic cell nanovesicles boost the immunotherapy of hepatocellular carcinoma after microwave ablation.

Microwave ablation (MWA) is a frequently adopted regional therapy for treating hepatocellular carcinoma (HCC) in clinic. However, incomplete microwave ablation (IMWA) is often inevitable due to the restraint of ablating large tumors or tumors in special locations, resulting in a high recurrence rate of HCC. Moreover, the most promising immune checkpoint blockade (ICB)-based immunotherapy is raising hindered by the toxicity and insufficient immune response. To overcome these barriers, we conjugate small nanovesicle (smDV)-derived from matured dendritic cells (mDCs) with anti-CTLA-4 antibody (smDV-aCTLA-4) using a metabolic tagging technology, which could trigger the infiltration of cytotoxic T cells (CTLs) and adopted tumor-infiltrating lymphocytes (TILs) in residual HCC after IMWA. In HCC microenvironment, the administration of smDV-aCTLA-4 could promote antigen presentation and immune checkpoint suppression to activate CTLs and improve the safety of anti-CTLA-4 antibody. Moreover, the anti-tumor efficacy of CTLs elicited by smDV-aCTLA-4 could also be further enhanced by anti-programmed death 1 (aPD-1) antibody. In addition, compared to the adoptive TILs therapy, the treatment using smDV-aCTLA-4-bonded TILs (smDV-aCTLA-4@TILs) could promote the proliferation and infiltration of cytotoxic TILs in residual HCC after IMWA. Our results clearly evidences the potency of a new type of engineered DC nanovesicles in reducing HCC recurrence after IMWA.

A combination of lymphatic drug delivery of anti-CTLA-4 antibody and local radiotherapy for solid-tumor treatment.

The combination of radiotherapy and immunotherapy is a promising approach that has been shown in clinical trials to improve significantly survival and response rates compared with monotherapy against solid tumor. Since anti-CTLA-4 antibodies block immunosuppressive signals mainly in the lymph nodes (LNs), efficient drug delivery to the lymphatic system is desirable. However, the immune checkpoint inhibitors, especially anti-CTLA-4 are currently administered intravenously (i.v.), resulting in limited efficacy in controlling solid tumor and inhibiting metastases, and the method of administration has not been optimized. Here, we show that a combination of local radiotherapy and administration of anti-CTLA-4 antibodies using a lymphatic drug delivery system (LDDS) suppresses solid tumor and metastases. We compared the efficacy of LDDS-based immunotherapy or radioimmunotherapy with i.v. administration in a solid-tumor model created by subcutaneous inoculation into LN-swollen mice with osteosarcoma cells. Tumor-bearing mice were divided into various groups (no treatment, immunotherapy [i.v. or LDDS], radiotherapy, and radioimmunotherapy [i.v. or LDDS]) and were observed for 28 days. Immunotherapy was administered with a cumulative dose of 10 mg/kg of anti-CTLA-4 monoclonal antibody, and radiotherapy was administered with a cumulative 8 Gy of fractionated X-ray irradiation. For immunotherapy alone, LDDS provided slight tumor growth inhibition but did not inhibit distant metastasis. For radioimmunotherapy, however, tumor growth was delayed and distant metastasis was suppressed compared with radiotherapy alone. In particular, the LDDS group achieved a high tumor-suppressive effect with T cell-mediated immune activity, indicating the efficacy of LDDS in radioimmunotherapy.

CD103+ cDC1 Dendritic Cell Vaccine Therapy for Osteosarcoma Lung Metastases.

BACKGROUND: We generated a CD103+DC vaccine using K7M3 OS cell lysates (cDCV) and investigated its ability to induce regression of primary tumors, established lung metastases, and a systemic immune response. METHODS: A bilateral tumor model was used to assess cDCV therapy efficacy and systemic immunity induction. K7M3 cells were injected into mice bilaterally. Right-sided tumors received PBS (control) or cDCV. Left-sided tumors were untreated. Tumor growth was compared between the vaccine-treated and untreated tumor on the contralateral side and compared to the control group. The immune cell profiles of the tumors, and tumor-draining lymph nodes (TdLNs) and spleen were evaluated. To determine the efficacy of systemic cDCV therapy against established lung metastases, K7M3 cells were injected intratibially. Leg amputation was performed 5 weeks later. Mice were treated intravenously with PBS or cDCV and euthanized 6 weeks later. Lungs, TdLNs and spleen were collected. The number and size of the lung nodules were quantified. The immune cell profile of tumor, and lymph nodes and spleen were also evaluated. Using this same model, we evaluated the effect of cDCV + anti-CTLA-4. RESULTS: cDCV therapy inhibited the treated and untreated tumors and increased the number of T-cells in these tumors and the lymph nodes compared to control-treated mice. Systemic cDCV therapy administered following amputation decreased the size and number of lung metastases, and increased T-cell numbers in the tumor and lymph nodes. Combining anti-CTLA-4 with cDCV therapy increased cDCV efficacy against lung metastases. CONCLUSIONS: Intratumor cDCV generated a systemic immune response inhibiting the growth of both the treated and untreated tumors, with increased T-cells in the tumor and lymph nodes. Systemic cDCV was effective against established lung metastases. Efficacy was increased by anti-CTLA4. cDCVs may provide a novel therapeutic approach for relapsed/metastatic OS patients.

Effectiveness of immune checkpoint inhibitors and other treatment modalities in patients with advanced mucosal melanomas: a systematic review and individual patient data meta-analysis.

Background: Mucosal melanomas (MM) are an aggressive subtype of melanoma. Given the rarity of this disease, the conduct of clinical trials is challenging and has been limited. Current treatment options have been extrapolated from the more common cutaneous melanoma even though MM is distinct in pathogenesis, etiology and prognosis. This is the first meta-analysis to comprehensively assess the efficacy of immune checkpoint inhibitors (anti-PD1 and anti-CTLA4) and other treatment modalities (targeted therapy such as KIT inhibitors and VEGF inhibitors, as well as radiotherapy) on survival outcomes in MM to develop clinical guidelines for evidence-based management. Methods: The protocol was prospectively registered on PROSPERO (PROSPERO ID: CRD42023411195). PubMed, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science and Google Scholar were searched from inception until 25 July 2024, for all cohort and observational studies. Eligible studies included those with five or more participants with locally advanced or metastatic MM treated with anti-PD1, anti-CTLA4, VEGF inhibitors and/or KIT inhibitors. Titles and abstracts of potential articles were screened and full texts of all potentially eligible studies were retrieved and reviewed by two independent reviewers. Individual patient data (IPD) from published Kaplan-Meier curves were reconstructed using a graphical reconstruction method and pooled as a one-stage meta-analysis. A sensitivity analysis using a two-stage meta-analysis approach was conducted. Extracted outcomes included overall survival (OS) and progression-free survival (PFS). For each treatment arm, median survival time and 12-month survival proportion were estimated. Data from double-arm trials was pooled to estimate hazard ratios (HRs), ratios of restricted mean time lost (RMTL) and restricted mean survival time (RMST). Findings: From a total of 7402 studies, 35 eligible studies comprising a total of 2833 participants were included. Combined anti-PD1 and anti-CTLA4 therapy had the highest 12-month OS and 12-month PFS at 71.8% (95% CI: 67.6%, 76.2%, n = 476) and 35.1% (95% CI: 30.5%, 40.4%, n = 401) respectively, followed by anti-PD1 therapy alone (OS: 64.0% (95% CI: 61.4%, 66.7%, n = 1399); PFS: was 28.3% (95% CI: 25.8%, 31.2%, n = 1142), anti-PD1 and VEGF inhibitor combination therapy (OS: 57.1% (95% CI: 51.0%, 63.9%)), KIT inhibitors (OS: 48.2% (95% CI: 37.6%, 61.8%); PFS: 8.3% (95% CI: 3.7%, 18.7%)) and anti-CTLA4 therapy alone (OS: 33.3% (95% CI: 28.4%, 39.1%); PFS: 9.8% (95% CI: 5.9%, 16.5%)). In the double-arm studies, combination therapy with anti-PD1 and anti-CTLA4 had similar OS and PFS with anti-PD1 alone (OS: HR 0.856 (95% CI: 0.704, 1.04); RMTL ratio 0.932 (95% CI: 0.832, 1.044, P = 0.225); RMST ratio 1.102 (95% CI: 0.948, 1.281, P = 0.204); PFS: HR 0.919 (95% CI: 0.788, 1.07); RMTL ratio 0.936 (95% CI: 0.866, 1.013, P = 0.100); RMST ratio 1.21 (95% CI: 0.979, 1.496, P = 0.078)), however, anti-PD1 therapy alone had significantly better PFS than anti-CTLA4 alone (HR 0.548 (95% CI: 0.376, 0.799); RMTL ratio 0.715 (95% CI: 0.606, 0.844, P < 0.001); RMST ratio 1.659 (95% CI: 1.316, 2.092, P < 0.001)). Anti-PD1 therapy with radiotherapy versus anti-PD1 alone showed no significant difference (OS: HR 0.854 (95% CI: 0.567, 1.29); RMTL ratio 0.855 (95% CI: 0.675, 1.083, P = 0.193); RMST ratio 1.194 (95% CI: 0.928, 1.536, P = 0.168; PFS: HR 0.994 (95% CI: 0.710, 1.39); RMTL ratio 1.006 (95% CI: 0.87, 1.162, P = 0.939); RMST ratio 0.984 (95% CI: 0.658, 1.472, P = 0.939)). Interpretation: For the systemic treatment of MM, anti-PD1 is the best monotherapy. While combining anti-PD1 with other treatment options such as anti-CTLA4, VEGF inhibitors or radiotherapy might achieve better outcomes, these improvements did not reach statistical significance when evaluated by HR, RMTL and RMST ratios. Funding: This work was supported by the National Medical Research Council Transition Award (TA20nov-0020), SingHealth Duke-NUS Oncology Academic Clinical Programme (08/FY2020/EX/67-A143 and 08/FY2021/EX/17-A47), the Khoo Pilot Collaborative Award (Duke-NUS-KP(Coll)/2022/0020A), the National Medical Research Council Clinician Scientist-Individual Research Grant-New Investigator Grant (CNIGnov-0025), the Terry Fox Grant (I1056) and the Khoo Bridge Funding Award (Duke-NUS-KBrFA/2024/0083I).

Comparing neoantigen cancer vaccines and immune checkpoint therapy unveils an effective vaccine and anti-TREM2 macrophage-targeting dual therapy.

The goal of therapeutic cancer vaccines and immune checkpoint therapy (ICT) is to promote T cells with anti-tumor capabilities. Here, we compared mutant neoantigen (neoAg) peptide-based vaccines with ICT in preclinical models. NeoAg vaccines induce the most robust expansion of proliferating and stem-like PD-1+TCF-1+ neoAg-specific CD8 T cells in tumors. Anti-CTLA-4 and/or anti-PD-1 ICT promotes intratumoral TCF-1- neoAg-specific CD8 T cells, although their phenotype depends in part on the specific ICT used. Anti-CTLA-4 also prompts substantial changes to CD4 T cells, including induction of ICOS+Bhlhe40+ T helper 1 (Th1)-like cells. Although neoAg vaccines or ICTs expand iNOS+ macrophages, neoAg vaccines maintain CX3CR1+CD206+ macrophages expressing the TREM2 receptor, unlike ICT, which suppresses them. TREM2 blockade enhances neoAg vaccine efficacy and is associated with fewer CX3CR1+CD206+ macrophages and induction of neoAg-specific CD8 T cells. Our findings highlight different mechanisms underlying neoAg vaccines and different forms of ICT and identify combinatorial therapies to enhance neoAg vaccine efficacy.

Immunotherapy after progression to double immunotherapy: pembrolizumab and lenvatinib versus conventional chemotherapy for patients with metastatic melanoma after failure of PD-1/CTLA-4 inhibition.

Background: Programmed cell death 1 receptor (PD-1) inhibition as monotherapy followed by Cytotoxic T-lymphocyte associated protein 4 (CTLA-4) inhibition in case of progression or as upfront double co-inhibition has drastically improved the survival outcomes of metastatic melanoma. Still, many patients develop primary or acquired resistance to both agents, relapse soon, and survive less. For these patients, the therapeutic options are very limited, and for many years, conventional chemotherapy (CC) was the standard of care. Recently, the phase II LEAP-004 trial supported that pembrolizumab/lenvatinib could potentially overcome anti-PD-1/anti-CTLA-4 immunotherapy refractoriness. Materials and methods: In the absence of any prospective comparative study and to evaluate in a real-world context the clinical benefit of re-administering a PD-1 inhibitor (pembrolizumab 200 mg i.v. every 3 weeks, Q3W) with a multi-kinase inhibitor (lenvatinib, but at a reduced dose 10 mg p.o. daily due to its known toxicity) in this frail population of unmet need, we conducted here a retrospective comparison of LEAP-004-proposed combination with CC (carboplatin 4 AUC and dacarbazine 850 mg/m2 i.v. Q3W) in melanoma patients who relapsed to both checkpoint inhibitors, either in combinatorial or in sequential setting, between July 2022 and January 2024. Baseline demographics, disease characteristics, and treatment outcomes (objective response rate (ORR), progression-free survival (PFS), and overall survival (OS)) were recorded. Survival analyses were performed using the Kaplan-Meier method. All patients were also considered for safety analysis. Results: A total of 84 patients were included in the effectiveness and safety analysis (pembrolizumab/lenvatinib, n=39 and CC, n=45). The median age was 67 (45-87) years and 64 (34-87) years, and men were 33.3% and 46.7%, respectively. The distribution of their metastatic sites was comparable, including 12.8% and 20% with brain involvement. Most patients had a good PS<2 (69.9% and 56.5%), increased lactate dehydrogenase (LDH) (71.8% and 84.4%), BRAF-wild status (82.1% and 84.8%), and received ≥2 previous systemic therapies (61.5% and 53.3%). The median follow-up was 18 months. The ORR was 23.1% and 11.1% (p<0.0001), the median PFS was 4.8 months and 3.8 months [HR (95%CI), 0.57 (0.36-0.92); p=0.017], and the median OS was 14.2 months and 7.8 months [HR (95%CI), 0.39 (0.22-0.69), p=0.0009] in pembrolizumab/lenvatinib and CC arms, respectively. Grade 3-5 treatment-related adverse events were documented in 48.7% (pembrolizumab/lenvatinib) and 75.6% (CC) of patients (p=0.034), which led to treatment discontinuation in 10.3% and 17.8% of cases, respectively. Conclusions: This is the first comparative study in patients with metastatic melanoma refractory to PD-1/CTLA-4 inhibition and showed significantly longer outcomes in cases treated with pembrolizumab/lenvatinib versus CC.

Inhibition of CTLA-4 accelerates atherosclerosis in hyperlipidemic mice by modulating the Th1/Th2 balance via the NF-κB signaling pathway.

Objective: Though an increased risk of atherosclerosis is associated with anti-CTLA-4 antibody therapy, the underlying mechanisms remain unclear. Methods: C57BL/6 mice were treated with anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) antibody twice a week for 4 weeks, after being injected with AAV8-PCSK9 and fed a Paigen diet (PD). The proportion of aortic plaque and lipid accumulation were assessed using Oil Red O staining, while the morphology of atherosclerotic lesions was analyzed with hematoxylin and eosin staining. Collagen content was evaluated through Picrosirius Red (PSR) staining, while inflammatory cell infiltration was examined with immunofluorescence staining. CD4+ T cells secreting IFN-γ and IL-4, which represent Th1 and Th2 cells respectively, were detected by flow cytometry and real-time PCR. Protein levels of p-IκBα, IκBα, p-p65, and p65 were determined by Western blot. Results: Inhibiting CTLA-4 exacerbated PD-induced plaque progression and promoted CD4+ T cell infiltration in the aortic root. The anti-CTLA-4 antibody promoted CD4+ T cell differentiation toward the Th1 type, as indicated by an increase in the Th1/Th2 ratio. Compared to the anti-IgG group, treatment with anti-CTLA-4 antibody significantly elevated the protein levels of p-IκBα and p-p65, as well as the mRNA levels of TNF-α, IL-6, ICAM-1, and VCAM-1. Inhibiting the NF-κB signaling pathway attenuated the overall pathological phenotype induced by the anti-CTLA-4 antibody treatment. Conclusion: Anti-CTLA-4 treatment promotes the progression of atherosclerosis by activating NF-κB signaling and modulating the Th1/Th2 balance. Our results provide a rationale for preventing and/or treating atherosclerosis accelerated by anti-CTLA-4 antibody therapy in cancer patients.

Unraveling Th subsets: insights into their role in immune checkpoint inhibitor therapy.

T helper (Th) cell subsets play pivotal roles in regulating immune responses within the tumor microenvironment, influencing both tumor progression and anti-tumor immunity. Among these subsets, Th1 cells promote cytotoxic responses through the production of IFN-γ, while Th2 cells and regulatory T cells (Tregs) exert immunosuppressive effects that support tumor growth. Th9 and Th17 cells have context-dependent roles, contributing to both pro-inflammatory and regulatory processes in tumor immunity. Tumor antigen-specific T cells within the tumor microenvironment often exhibit a dysfunctional phenotype due to increased expression of inhibitory receptors such as CTLA-4 and PD-1, leading to reduced antitumor activity. Monoclonal antibodies that block these inhibitory signals-collectively known as immune checkpoint inhibitors (ICIs)-can reactivate these T cells, enhancing their ability to target and destroy cancer cells. Recent advancements have highlighted the critical role of T helper subsets in modulating responses to ICIs, with their interactions remaining a focus of ongoing research. Both positive and negative effects of ICIs have been reported in relation to Th cell subsets, with some effects depending on the type of tumor microenvironment. This review summarizes the crucial roles of different T helper cell subsets in tumor immunity and their complex relationship with immune checkpoint inhibitor therapy.

Immunotherapeutic Innovations in Clear Cell Renal Cell Carcinoma: Current Strategies and Future Directions.

Approximatively 80% of kidney cancers globally are clear cell kidney cancers (ccRCCs), with 80% of these malignancies featuring an inactivating mutation of the Von Hippel-Lindau gene. This genetic alteration leads to the stabilization of hypoxia inducible factors 1 and 2 alpha (HIF 1 and 2α), resulting in the over-expression of target genes such as vascular endothelial growth factor (VEGF), which is crucial for angiogenesis. As a result, ccRCCs are highly vascularized and serve as models for anti-angiogenic treatments (AAT). Current AAT therapies comprise antibodies targeting VEGFs, tyrosine kinase inhibitors (TKi) (Sunitinib) that target neo-angiogenesis receptors, and competitive inhibitor receptors (Aflibercept) that trap VEGFA and PlGF. The over-expression of VEGF and related members such as VEGFC significantly influences angiogenesis, lymph-angiogenesis, and immune tolerance. This has resulted in the approval of various immune checkpoint inhibitors (known as anti-PD-1, anti-PD-L1, and anti-CTLA-4) as viable treatment options for kidney cancer. Despite these advances, ccRCC remains challenging to treat adequately. Thus, future research is imperative to better understand the biology and pathophysiology of RCC, the tumor microenvironment, and mechanisms of resistance, with the aim of developing new therapies.

Lymphocyte T Subsets and Outcome of Immune Checkpoint Inhibitors in Melanoma Patients: An Oncologist's Perspective on Current Knowledge.

Melanoma is the most aggressive and deadly form of skin cancer, and its incidence has been steadily increasing over the past few decades, particularly in the Caucasian population. Immune checkpoint inhibitors (ICI), anti-PD-1 monotherapy or in combination with anti-CTLA-4, and more recently, anti-PD-1 plus anti-LAG-3 have changed the clinical evolution of this disease. However, a significant percentage of patients do not benefit from these therapies. Therefore, to improve patient selection, it is imperative to look for novel biomarkers. Immune subsets, particularly the quantification of lymphocyte T populations, could contribute to the identification of ICI responders. The main purpose of this review is to thoroughly examine significant published data on the potential role of lymphocyte T subset distribution in peripheral blood (PB) or intratumorally as prognostic and predictive of response biomarkers in advanced melanoma patients treated with ICI regardless of BRAFV600 mutational status.

Immune checkpoint inhibitor-induced diarrhea and colitis: an overview.

Immune checkpoint inhibitors (ICIs) have emerged as an integral component of the management of various cancers and have contributed to significant improvements in overall survival. Most available ICIs target anti-cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA4), and anti-programmed cell death 1/programmed cell death ligand 1 (anti-PD1/PDL1). Gastrointestinal immune-related adverse events remain a common complication of ICIs. The predominant manifestations include diarrhea and colitis, which often manifest concurrently as immune-mediated diarrhea and colitis (IMDC). Risk factors for developing these side effects include baseline gut microbiota, preexisting autoimmune disorders, such as inflammatory bowel disease, and type of neoplasm. The hallmark symptom of colitis is diarrhea which may be accompanied by mucus or blood in stools. Patients may also experience abdominal pain, fever, vomiting, and nausea. If not treated rapidly, ICI-induced colitis can lead to serious life-threatening complications. Current management is based on corticosteroids as first-line, and immunosuppressants like infliximab or vedolizumab for refractory cases. Microbiota transplantation and specific cytokines and lymphocyte replication inhibitors are being investigated. Optimal patient care requires maintaining a balance between treatment toxicity and efficacy, hence the aim of this review is to enhance readers' comprehension of the gastrointestinal adverse events associated with ICIs, particularly IMDC. In addition to identifying the risk factors, we discuss the incidence, clinical presentation, workup, and management options of IMDC.

Potentiating Salvage Radiotherapy in Radiorecurrent Prostate Cancer Through Anti-CTLA4 Therapy: Implications from a Syngeneic Model.

High-risk prostate cancer (PCa) is a leading cause in cancer death and can elicit significant morbidity and mortality. Currently, the salvage of local disease recurrence after radiation therapy (RT) is a major clinical problem. Immune checkpoint inhibitors (ICIs), which enhance immune activation, have demonstrated clinical therapeutic promise in combination with ionizing radiation (IR) in certain advanced cancers. We generated the TRAMP-C2 HF radiorecurrent syngeneic mouse model to evaluate the therapeutic efficacy of ICIs in combination with RT. The administration of anti-PDL1 and/or anti-CTLA4 did not achieve a significant tumor growth delay compared to the control. The combination of IR and anti-PDL1 did not yield additional a growth delay compared to IR and the isotype control. Strikingly, a significant tumor growth delay and complete cure in one-third of the mice were seen with the combination of IR and anti-CTLA4. Immune cells in tumor-draining lymph nodes and tumor-infiltrating lymphocytes from mice treated with IR and anti-CTLA4 demonstrated an upregulation of genes in T-cell functions and enrichment in both CD4+ and CD8+ T-cell populations compared to mice given IR and the isotype control. Taken together, these results indicate enhancement of T-cell response in radiorecurrent PCa by IR and anti-CTLA4.

To switch or to swap? Evidence from a meta-analysis for the best treatment approach in childhood chronic uveitis resistant to the I anti-TNF.

Objective: Since adalimumab approval in childhood chronic non-infectious uveitis (cNIU), the prognosis has been dramatically changed, but the 25 % failed to achieve inactivity. There is not accordance if it is better to switch to another anti-TNF or to swap to another category of biologic. Thus, we aim to summarize evidence regarding the best treatment of cNIU refractory to the first anti-TNF. Methods: A systematic literature review and meta-analysis, according to PRISMA Guidelines, was performed(Jan2000-Aug2023). Studies investigating the efficacy of treatment in cNIU refractory to the first anti-TNF were considered for inclusion. The primary outcome was the improvement of intraocular inflammation according to SUN. A combined estimation of the proportion of children responding to switch or swap and for each drug was performed. Results: 23 articles were eligible, reporting 150 children of whom 109 switched anti-TNF (45 adalimumab, 49 infliximab, 9 golimumab) and 41 swapped to another biologics (31 abatacept, 8 tocilizumab and 1 rituximab). The proportion of responding children was 46 %(95 % CI 23-70) for switch and 38 %(95 % CI 8-73) for swap (χ20.02, p = 0.86). Instead analysing for each drug, the proportion of responding children was the 24 %(95 % CI 2-55) for adalimumab, 43 %(95 % CI 2-80) for abatacept, 79 %(95 % CI 61-93) for infliximab, 56 %(95 % CI 14-95) for golimumab and 96 %(95 % CI 58-100) for tocilizumab. We evaluated a superiority of tocilizumab and infliximab compared to the other drugs(χ2 27.5 p < 0.0001). Conclusion: Although non-conclusive, this meta-analysis suggests that, after the first anti-TNF failure, tocilizumab and infliximab are the best available treatment for the management of cNIU.

Fc-enhanced anti-CTLA-4, anti-PD-1, doxorubicin, and ultrasound-mediated BBB opening: A novel combinatorial immunotherapy regimen for gliomas.

BACKGROUND: Glioblastoma is a highly aggressive brain cancer that is resistant to conventional immunotherapy strategies. Botensilimab, an Fc-enhanced anti-CTLA-4 antibody (FcE-aCTLA-4), has shown durable activity in "cold" and immunotherapy-refractory cancers. METHOD: We evaluated the efficacy and immune microenvironment phenotype of a mouse analogue of FcE-aCTLA-4 in treatment-refractory preclinical models of glioblastoma, both as a monotherapy and in combination with doxorubicin delivered via low-intensity pulsed ultrasound and microbubbles (LIPU/MB). Additionally, we studied 4 glioblastoma patients treated with doxorubicin, anti-PD-1 with concomitant LIPU/MB to investigate the novel effect of doxorubicin modulating FcγR expressions in tumor associated macrophages/microglia (TAMs). RESULTS: FcE-aCTLA-4 demonstrated high-affinity binding to FcγRIV, the mouse ortholog of human FcγRIIIA, which was highly expressed in TAMs in human glioblastoma, most robustly at diagnosis. Notably, FcE-aCTLA-4 mediated selective depletion of intra-tumoral regulatory T cells (Tregs) via TAM-mediated phagocytosis, while sparing peripheral Tregs. Doxorubicin, a chemotherapeutic drug with immunomodulatory functions, was found to upregulate FcγRIIIA on TAMs in glioblastoma patients who received doxorubicin and anti-PD-1 with concomitant LIPU/MB. In murine models of immunotherapy-resistant gliomas, a combinatorial regimen of FcE-aCTLA-4, anti-PD-1, and doxorubicin with LIPU/MB, achieved a 90% cure rate, that was associated robust infiltration of activated CD8+ T cells and establishment of immunological memory as evidenced by rejection upon tumor rechallenge. CONCLUSION: Our findings demonstrate that FcE-aCTLA-4 promotes robust immunomodulatory and anti-tumor effects in murine gliomas and is significantly enhanced when combined with anti-PD-1, doxorubicin, and LIPU/MB. We are currently investigating this combinatory strategy in a clinical trial (clinicaltrials.gov NCT05864534).

Immunotherapy-induced colitis in metastatic colorectal cancer: a systematic review and meta-analysis.

Colorectal cancer (CRC) presents significant mortality risks, underscoring the urgency of timely diagnosis and intervention. Advanced stages of CRC are managed through chemotherapy, targeted therapy, immunotherapy, radiotherapy, and surgery. Immunotherapy, while effective in bolstering the immune system against cancer cells, often carries toxic side effects, including colitis. This study aimed to evaluate the incidence of colitis in patients with metastatic CRC (mCRC) undergoing various immunotherapy treatments. Through a systematic search of Google Scholar and PubMed databases from inception until November 2023, nine relevant studies were identified. Subgroup analyses revealed a higher incidence of colitis, particularly in patients treated with anti-cytotoxic T-lymphocyte-associated molecule-4 (anti-CTLA-4) and combination therapies compared to monotherapy with programmed cell death receptor-1 (PD-1) or programmed cell death ligand receptor-1 (PDL-1) inhibitors. Notably, naive-treated metastatic CRC patients exhibited elevated colitis incidences compared to those previously treated. In conclusion, anti-CTLA-4 and combination therapies, such as nivolumab plus ipilimumab, were associated with increased colitis occurrences in metastatic CRC patients, highlighting the need for vigilant monitoring and management strategies, especially in immunotherapy-naive individuals.

Post-immunotherapy CTLA-4 Ig treatment improves antitumor efficacy.

Immune checkpoint therapies (ICT) improve overall survival of patients with cancer but may cause immune-related adverse events (irAEs) such as myocarditis. Cytotoxic T lymphocyte-associated antigen 4 immunoglobulin fusion protein (CTLA-4 Ig), an inhibitor of T cell costimulation through CD28, reverses irAEs in animal models. However, concerns exist about potentially compromising antitumor response of ICT. In mouse tumor models, we administered CTLA-4 Ig 1) concomitantly with ICT or 2) after ICT completion. Concomitant treatment reduced antitumor efficacy, while post-ICT administration improved efficacy without affecting frequency and function of CD8 T cells. The improved response was independent of the ICT used, whether CTLA-4 or PD-1 blockade. The frequency of Tregs was significantly decreased with CTLA-4 Ig. The resulting increased CD8/Treg ratio potentially underlies the enhanced efficacy of ICT followed by CTLA-4 Ig. This paradoxical mechanism shows that a CTLA-4 Ig regimen shown to reduce irAE severity does not compromise antitumor efficacy.

Anti-PD-1 alone or in combination with anti-CTLA-4 for advanced melanoma patients with liver metastases.

BACKGROUND: The combination of anti-PD-1 and anti-CTLA-4 has been associated with improvement in response and survival over anti-PD-1 monotherapy in unselected patients with advanced melanoma. Whether patients with liver metastases also benefit from the combination of anti-PD-1 and anti-CTLA-4 over anti-PD-1, is unclear. In this study, we sought to assess whether the combination of anti-PD-1 and anti-CTLA-4 leads to better response, progression-free survival and overall survival, compared with anti-PD-1 monotherapy for patients with liver metastases. METHODS: We have conducted an international multicentre retrospective study. Patients with advanced melanoma with liver metastases treated with 1st line anti-PD1 monotherapy or with anti-CTLA-4 were included. The endpoints of this study were: objective response rate, progression-free survival and overall survival. RESULTS: With a median follow-up from commencement of anti-PD-1 monotherapy or in combination with anti-CTLA-4 of 47 months (95% CI, 42-51), objective response rate was higher with combination therapy (47%) versus anti-PD-1 monotherapy (35%) (p = 0.0027), while progression-free survival and overall survival were not statistically different between both treatment groups. However, on multivariable analysis with multiple imputation for missing values and adjusting for predefined variables, combination of anti-PD1 and anti-CTLA-4 was associated with higher objective response (OR 2.21, 1.46 - 3.36; p < 0.001), progression-free survival (HR 0.73, 0.57 - 0.92; p = 0.009) and overall survival (HR 0.71, 0.54 - 0.94; p = 0.018) compared to anti-PD1 monotherapy. CONCLUSIONS: Findings from this study will help guide treatment selection for patients who present with liver metastases, suggesting that combination therapy should be considered for this group of patients.

Evaluation of a Combinatorial Immunotherapy Regimen That Can Cure Mice Bearing MYCN-Driven High-Risk Neuroblastoma That Resists Current Clinical Therapy.

Background: Incorporating GD2-targeting monoclonal antibody into post-consolidation maintenance therapy has improved survival for children with high-risk neuroblastoma. However, ~50% of patients do not respond to, or relapse following, initial treatment. Here, we evaluated additional anti-GD2-based immunotherapy to better treat high-risk neuroblastoma in mice to develop a regimen for patients with therapy-resistant neuroblastoma. Methods: We determined the components of a combined regimen needed to cure mice of established MYCN-amplified, GD2-expressing, murine 9464D-GD2 neuroblastomas. Results: First, we demonstrate that 9464D-GD2 is nonresponsive to a preferred salvage regimen: anti-GD2 with temozolomide and irinotecan. Second, we have previously shown that adding agonist anti-CD40 mAb and CpG to a regimen of radiotherapy, anti-GD2/IL2 immunocytokine and anti-CTLA-4, cured a substantial fraction of mice bearing small 9464D-GD2 tumors; here, we further characterize this regimen by showing that radiotherapy and hu14.18-IL2 are necessary components, while anti-CTLA-4, anti-CD40, or CpG can individually be removed, and CpG and anti-CTLA-4 can be removed together, while maintaining efficacy. Conclusions: We have developed and characterized a regimen that can cure mice of a high-risk neuroblastoma that is refractory to the current clinical regimen for relapsed/refractory disease. Ongoing preclinical work is directed towards ways to potentially translate these findings to a regimen appropriate for clinical testing.