Double Haploidentical Hematopoietic Stem Cell Transplantation (HSCT) Enhances Anti-Tumor Activity After Transplant

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1897-1897
Author(s):  
Tulin Budak-Alpdogan ◽  
Cavan P Bailey ◽  
Michelle Panis ◽  
Christopher Sauter ◽  
Vikas Agrawal ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cell ◽  
Tumor Growth ◽  
Low Dose ◽  
Tumor Model ◽  
Tumor Escape ◽  
Tumor Bearing ◽  
Mhc Haplotype ◽  
Anti Tumor Activity

Abstract Abstract 1897 We have previously shown that haploidentical (HI) HSCT with low dose donor T-cell infusion provides a survival advantage in tumor bearing mice when compared to parent F1 or MHC-matched transplant models. We suggest that MHC difference in HI-HSCT generates early T-cell clonal activation against the unshared MHC haplotype, which eliminates residual tumor cells that express the unshared MHC haplotype. However, alteration in MHC antigen expression is a significant contributor to tumor escape from graft-versus-tumor (GVT) activity. Recent haploidentical transplant data revealed that uniparental disomy, the loss of the HLA haplotype, is a clinically relevant mechanism of tumor escape that leads to post-transplant leukemia relapse. Murine renal cell carcinoma, RENCA-TGL, cell line normally expresses only H2Kd as a MHC molecule. Therefore, in our haploidentical transplant model, T cell clonal activity is usually restricted against H2Kd molecule only. For circumventing the single haplotype expression of tumor model, we transfected this cell line with a H2Kb expressing vector, pAcGFP-NeoR-H2Kb, and generated stable clones with G418 selection. The clone that has more than 95% H2Kb expression used for in vivo experiments. Both tumor cell lines, i.e. parental and transfected clone, had similar in vivo tumor growth acceptance and growth rate. We then used two different haploidentical donors that were targeting different MHC haplotypes. Lethally irradiated B6D2F1 (H2Kb/d) mice were transplanted with T cell depleted bone marrow (TCD-BM) from either B6C3F1 (H-2Kb/k) (single haplo-1; SH1), or C3D2F1 (H2Kk/d) (single haplo 2; SH2) or both donor mice with low-dose (1×105) T-cells. In some experiments, animals were also injected either H2Kd or H2Kb/d expressing RENCA-TGL cells for the evaluation of GVT activity. Bone marrow (BM), spleens and thymi were harvested from recipients of single and double HI-HSCT at day 35 and showed similar cellularities. Interestingly, spleen and bone marrow had similar chimerism from both donors in DH-HSCT. There were no early transplant mortality, graft failure, weight loss and GVHD scoring difference among the double or single-haploidentical transplant recipients. In two other sets of experiments, we followed the tumor growth and the survival of tumor bearing mice after transplant. The recipients of DH-HSCT showed a better survival and GVT activity than the recipients of SH-HSCT in RENCA-TGL (H2Kb/d) bearing tumor model. These observations confirmed that MHC targeting plays a prominent role in tumor surveillance, and immune targeting the unshared MHC haplotype with haploidentical transplant induce remarkable survival advantage. Double HI-HSCT provides an unique anti-tumor activity that continues to exert GVT effect, even in case of MHC haplotype loss. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Platelet-derived thrombospondin-1 is a critical negative regulator and potential biomarker of angiogenesis

Blood ◽  
2010 ◽  
Vol 115 (22) ◽  
pp. 4605-4613 ◽  
Author(s):  
Alexander Zaslavsky ◽  
Kwan-Hyuck Baek ◽  
Ryan C. Lynch ◽  
Sarah Short ◽  
Jenny Grillo ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Tumor Growth ◽  
Tumor Angiogenesis ◽  
Angiogenesis Inhibitor ◽  
Negative Regulator ◽  
Mouse Tumor ◽  
Tumor Bearing ◽  
Potential Biomarker ◽  
Thrombospondin 1

Abstract The sequential events leading to tumor progression include a switch to the angiogenic phenotype, dependent on a shift in the balance between positive and negative angiogenic regulators produced by tumor and stromal cells. Although the biologic properties of many angiogenesis regulatory proteins have been studied in detail, the mechanisms of their transport and delivery in vivo during pathologic angiogenesis are not well understood. Here, we demonstrate that expression of one of the most potent angiogenesis inhibitors, thrombospondin-1, is up-regulated in the platelets of tumor-bearing mice. We establish that this up-regulation is a consequence of both increased levels of thrombospondin-1 mRNA in megakaryocytes, as well as increased numbers of megakaryocytes in the bone marrow of tumor-bearing mice. Through the use of mouse tumor models and bone marrow transplantations, we show that platelet-derived thrombospondin-1 is a critical negative regulator during the early stages of tumor angiogenesis. Collectively, our data suggest that the production and delivery of the endogenous angiogenesis inhibitor thrombospondin-1 by platelets may be a critical host response to suppress tumor growth through inhibiting tumor angiogenesis. Further, this work implicates the use of thrombospondin-1 levels in platelets as an indicator of tumor growth and regression.

Blockade of the CD47/SIRPα Checkpoint Potentiates the Anti-Tumor Efficacy of Tafasitamab

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 11-12
Author(s):  
Doris Mangelberger ◽  
Christian Augsberger ◽  
Karin Landgraf ◽  
Christina Heitmüller ◽  
Stefan Steidl
Keyword(s):  
Monoclonal Antibody ◽  
Tumor Growth ◽  
B Cell ◽  
Tumor Model ◽  
B Cell Lymphoma ◽  
Checkpoint Blockade ◽  
Subcutaneous Tumor ◽  
Anti Tumor Activity

Introduction Tafasitamab (MOR208) is an Fc-enhanced, humanized, monoclonal antibody that targets CD19 and has shown promising clinical activity in patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL). CD19 is homogeneously expressed among different B-cell malignancies, and the binding of tafasitamab to CD19 directly mediates cell death, induces antibody-dependent cellular cytotoxicity and antibody-dependent cellular phagocytosis. Aiming to potentiate the tafasitamab-mediated "eat me" signal, we tested a combination with a CD47-directed monoclonal antibody (mAb) to inhibit the CD47/SIRPα "don't eat me" signal and further enhance macrophage-mediated phagocytosis. Preclinical studies demonstrated that blocking the CD47/SIRPα checkpoint in combination with antibodies, such as rituximab, increased phagocytosis by macrophages, resulting in effective anti-tumor effects in non-Hodgkin lymphoma (NHL) (Chao, et al. 2010). Additionally, the combination of the anti-CD47, magrolimab, and the anti-CD20, rituximab, demonstrated beneficial outcomes for patients with refractory NHL (Advani, et al. 2019). Here, we present in vitro and in vivo data on the combinatory effect of tafasitamab and an anti-CD47 mAb in preclinical models of Burkitt's lymphoma (BL). Methods During in vitro studies, CD14+ monocytes were isolated from the whole blood of healthy volunteers and differentiated with 50 ng/mL M-CSF for 6 days. ADCP was analyzed by flow cytometry in co-culture experiments with Ramos cells (BL) after 3 hours of treatment with tafasitamab and anti-CD47 mAb (clone B6H12). In vivo, the combination of tafasitamab with an anti-CD47 mAb was tested in a Ramos disseminated survival and subcutaneous tumor model in SCID and NOD-SCID mice, respectively. In both models, tafasitamab was administered therapeutically twice a week either at 3 mg/kg (disseminated) or 10 mg/kg (subcutaneous) for max. 4 weeks. The anti-CD47 mAb was administered at 4 mg/kg three times per week. Main study readouts were to assess animal survival and any delays in tumor growth. Results The combination of tafasitamab + CD47/SIRPα checkpoint blockade enhanced ADCP activity of primary M2 macrophages on BL-derived Ramos cells, in comparison with the anti-CD47 mAb or tafasitamab monotherapies (Figure 1A). In vivo, a significant increase in anti-tumor activity was observed with the combination of tafasitamab + anti-CD47 mAb. In the Ramos disseminated survival model, the combination showed an increased life span (ILS) of >182% compared with tafasitamab monotherapy control, with an overall survival of all animals treated with the combination (15/15) until the end of the study (Day 99 post-cell injection). Additionally, pronounced anti-tumor efficacies were detected in the Ramos subcutaneous tumor model. Here, the combination resulted in a significant delay in tumor growth compared with the tafasitamab or anti-CD47 mAb monotherapies (ILS >175% tafasitamab and ILS >72% anti-CD47 mAb vs tafasitamab + B6H12) (Figure 1B). Conclusions The ADCP activity of primary macrophages was increased by combining tafasitamab with an anti-CD47 mAb in vitro, resulting in enhanced anti-tumor activity compared with tafasitamab or anti-CD47 mAb monotherapies in vivo. Overall, results indicate the combination of tafasitamab with a CD47/SIRPα checkpoint blockade may be a promising novel combination approach for lymphoma therapy. Disclosures Mangelberger: MorphoSys AG: Current Employment. Augsberger:MorphoSys AG: Current Employment. Landgraf:MorphoSys AG: Current Employment. Heitmüller:MorphoSys AG: Current Employment. Steidl:MorphoSys AG: Current Employment.

Dipeptidyl Peptidase Inhibition Accelerates Dendritic Cell Cross Priming of Tumor-Reactive T Cells Resulting in Regression of Established Tumors

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2579-2579
Author(s):  
Meghaan Walsh ◽  
Aviva C Krauss ◽  
Jessica PE Davis ◽  
Su Young Kim ◽  
Martin Guimond ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Tumor Growth ◽  
Tumor Regression ◽  
High Dose ◽  
Complete Regression ◽  
Tumor Bearing ◽  
Dc Vaccine ◽  
Dipeptidyl Peptidases

Abstract BACKGROUND: PT-100 is an aminoboronic dipeptide that competitively inhibits dipeptidyl peptidases. While PT-100 has no direct effect on tumor cells in vitro, it exhibits potent antitumor effects in vivo. We have shown that female C57BL/6 (B6) mice with MB49 tumors, which naturally express the male minor histocompatibility antigen complex (HY), are primed to HY, but the immune response is insufficient to control tumor growth. In this study, we used the well-characterized HY antigen system to examine the immunomodulatory effects of PT-100 during treatment-induced tumor regression. METHODS: B6 female mice were inoculated subcutaneously with MB49 (106 cells) on day 0 and treated daily with PT-100 by gavage. For re-challenge experiments mice received high dose MB49 (3×106 cells) three weeks after complete regression of primary tumors. IFN-g ELISPOT was used to measure HY antigen specific T cell responses in the spleen and lymph nodes (LNs) during tumor growth. For adoptive transfer experiments, T cells were magnetic-bead purified from LNs and spleens of tumor-bearing PT-100 treated, tumor-bearing sham treated, or naïve mice and injected intravenously into Rag1−/− recipients (1.2×106 cells) which were then inoculated with high dose MB49. T cells were depleted with monoclonal antibodies to CD4 and CD8. Dendritic cells (DCs) were depleted with diphtheria toxin (DT) in bone marrow chimeras expressing the DT receptor under the CD11c promoter. DC activation examined by flow cytometry. For vaccine experiments, HY-expressing DCs were cultured from male B6 bone marrow and injected intraperitoneally (1×105 cells). RESULTS: PT-100 treatment resulted in complete regression of MB49, even when limited to the first week (days 3–7) during tumor progression. Treatment started later than week 1 was insufficient to establish consistent, complete tumor regression. High-dose re-challenge of PT-100 treated mice resulted in initial growth followed by regression without additional PT-100. IFN-gELISPOT revealed a robust response against HY in spleens of controls on day 17. Interestingly, PT-100 treated mice had quantitatively similar priming, but the response peaked earlier (day 10), just prior to tumor regression. Purified T cells from PT-100 treated donors collected on day 17 mediated markedly enhanced tumor protection compared to recipients of T cells from sham treated tumor-bearing mice despite significantly more HY-reactive cells in the spleen and LNs of sham treated-tumor bearing mice by that time. T cell or DC depletion independently abrogated the anti-tumor effect of PT-100 and treatment with PT-100 increased CD80 and CD86 expression on LN DC populations in vivo. Although HY DC vaccination does not affect tumor growth, supplementation of the DC vaccine with PT-100 mediated a therapeutic effect resulting in regression of well-established tumors. CONCLUSIONS: PT-100 establishes a consistent and potent antitumor effect against MB49 dependent on T cells and DCs. Treatment results in a memory response that is protective against high dose MB49 re-challenge. PT-100-induced tumor regression is associated with enhanced early tumor priming, associated with increases in activated DCs. T cells from PT-100 treated mice elicit superior protection upon adoptive transfer compared to shams, despite quantitatively less tumor-primed T cells, suggesting the PT-100 antitumor effect may involve a qualitative difference in T cell function. PT-100 given as an adjuvant to a DC vaccine results in increased potency and regression of established tumors. Inhibition of dipeptidyl peptidases modulate naturally occurring anti-tumor immune responses and contribute to the generation of a therapeutic anti-cancer vaccine.

Distinct Role of Antigen-Specific Tc1 and Tc17 Cells in Tumor Eradication In Vivo

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1910-1910
Author(s):  
Yu Yu ◽  
Hyun Il Cho ◽  
Dapeng Wang ◽  
Kane Kaosaard ◽  
Claudio Anasetti ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Tumor Growth ◽  
Tumor Immunity ◽  
Conflicts Of Interest ◽  
B16 Melanoma ◽  
Host Cells ◽  
Tumor Bearing ◽  
Tc17 Cells

Abstract Abstract 1910 Background: Adoptive cell transfer (ACT) of tumor-reactive T cells is one of the most promising approaches for the treatment of established melanoma. Recently, limited studies provide some evidence that Th/Tc17 cells may also have potent anti-tumor activities, but the conclusion is far from reach. Methods: Human gp10025-specific Tc1 or Tc17 cells were generated from pmel-1 transgeneic mice and used as cell source for ACT. Luciferase-transduced B16 melanoma was intravenously injected into C57BL/6 mice to establish lung-metastasis. After 7 days, tumor-bearing mice were lethally irradiated and transferred gp-10025 specific Tc1 or Tc17 cells in the combination of syngeneic bone marrow. Survival of those tumor-bearing mice was monitored daily, and tumor growth was monitored weekly using in vivo bioluminescent imaging (BLI). Donor T-cell expansion and cytokine secretion from the spleen and lung of tumor bearing mice were analyzed using flow cytometry and ELISPOT assays. To evaluate the role of IFNγ in anti-tumor immunity, we used a B16 melanoma cell line that was transduced with a plasmid encoding a dominant-negative IFNγ receptor (B16-IFNγRDN), and IFNγR knockout mice as tumor-bearers. Results: As expected, irradiation and transfer of syngeneic bone marrow had little or no effect on established melanoma. Adoptive transfer of tumor-specific Tc17 cells significantly suppressed the tumor growth, whereas Tc1 cells induced long-term regression of established melanoma. After ACT, Tc1 cells maintained their phenotype to produce IFNγ. However, Tc17 cells largely preserved their ability to produce IL-17, but a subset of them secreted IFNγ, indicating the plasticity of Tc17 cells in vivo. Mechanistically, Tc1 cells executed their anti-tumor immunity primarily through the direct effect of IFNγ on melanoma cells because Tc1 cells had essentially no effect on B16-IFNγRDN tumor. However, Tc1 cells had a similar therapeutic effect on IFNγR knockout as wild type mice, indicating that IFNγ signaling in host cells was not critical. In contrast, despite the fact that Tc17 cells also secreted IFNγ, Tc17-mediated anti-tumor immunity was independent of the effect through IFNγ. Ironically, IFNγ was inhibitory to Tc17-mediated anti-tumor activity. Conclusions: Taken together, these studies demonstrate that both Tc1 and Tc17 cells can mediate effective anti-tumor immunity, but Tc1 is superior to Tc17. These findings also demonstrated for the distinct effect mechanisms of antigen-specific Tc1 and Tc17 cells in anti-tumor response, and direct IFNγ signaling on tumor cells is a key effect to eradicate established tumors mediated by Tc1 cells. Disclosures: No relevant conflicts of interest to declare.

scholarly journals 107 Armoring NKG2D CAR T cells with IL-18 improves in vivo anti-tumor activity

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A118-A118
Author(s):  
Eytan Breman ◽  
Ann-Sophie Walravens ◽  
Isabelle Gennart ◽  
Amelie Velghe ◽  
Thuy Nguyen ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Car T Cells ◽  
Tumor Bearing ◽  
Car T Cell ◽  
Car T ◽  
High Doses ◽  
Anti Tumor Activity

BackgroundWhilst delivering impressive clinical efficacy in certain hematological malignancies, Chimeric Antigen Receptor (CAR) T cell therapy has yet to deliver significant clinical impact across a broader array of cancer indications. Armoring CAR T through the co-expression of immune modifying cytokines is an approach that may aid anti-cancer activity but is currently at an embryonic stage of development. In this study, the potential benefit of expressing IL-18 alongside a NKG2D CAR was assessed.MethodsA series of retroviral vectors encoding the NKG2D CAR (a fusion of NKG2D with CD3z), a cell surface tag to facilitate cell selection and tracking (truncated CD19) either with or without full length IL-18 were compared. In certain vectors, a single shRNA targeting CD3z was included to generate allogeneic CAR T versions. All transgenes were delivered as a single vector expressed under the control of the retroviral promoter with individual 2A elements ensuring equimolar levels of protein expression. T cells transduced with the individual vectors were challenged in vitro and in vivo to determine the impact of IL-18 upon NKG2D CAR directed function.ResultsArmored NKG2D CAR T cells that included the IL-18 transgene showed high levels of IL-18 secretion in culture and increased levels of interferon gamma secretion upon antigen challenge as compared to non-armored NKG2D CAR T cells. Armored NKG2D CAR T cells also showed prolonged sequential target cell killing as compared to non-armored CAR T versions. Importantly, in an in vivo stress test where the dose of non-armored NKG2D T cells was reduced to a level where minimal anti-tumor activity and survival above control was seen using an established THP-1 model, armored CAR T cells showed enhanced anti-tumor activity (as determined by bioluminescence) and overall survival. Interestingly, at high doses of armored CAR T cells, toxicity was seen in some tumor bearing models. This toxicity was abrogated by systemic infusion of human IL-18 binding protein (IL-18BP).ConclusionsArmoring NKG2D CAR T cells with IL-18 resulting in increased in vitro and in vivo target-dependent anti-tumor activity. The transient toxicity observed with high doses of the armored CAR T in tumor bearing models was eliminated by IL-18BP. Together, these observations imply that armoring NKG2D CAR T cells with IL-18 is likely to drive improved anti-tumor activity of the CAR T cell in line with previous publications1 2 while the presence of systemic IL-18BP3 should negate possible toxicities arising from high level constitutive expression of the cytokine.ReferencesChmielewski M, Abken H. Cell Reports 2017;21(11): 3205–32192.Hu B, Ren J, Luo Y, Keith B, Young R, Scholler J, Zhao Y, June C. Cell Reports 2017; 20(13): 3025–30333.Dinarello C, Novick D, Kim S, Kaplamski G. Frontiers in Immunology 2013;4;289

Myeloid Suppressive Cells Mobilized by GM-CSF in Non-Tumor Bearing Mice Are Dependent On Interferon Gamma for Function

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 832-832
Author(s):  
Mark A. Schroeder ◽  
Julie Ritchey ◽  
John F. DiPersio
Keyword(s):  
Bone Marrow ◽  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
T Cell Proliferation ◽  
Suppressive Function ◽  
Gm Csf ◽  
Tumor Bearing

Abstract Abstract 832 Myeloid-derived-suppressor cells (MDSCs) are enriched in tumors, and exist to a lesser extent in the blood, spleen and bone marrow of tumor bearing mice. Monocytic MDSCs (monoMDSCs) suppress CD8+ T-cells via expression of Arginase 1 (ARG1) and inducible nitric oxide synthase (iNOS). Tumor derived factors are critical to the maintenance of MDSCs and preventing differentiation to mature macrophages and dendritic cells. GM-CSF is a hematopoietic cytokine that can be secreted by tumors and promotes MDSC generation. Cells phenotypically similar to MDSCs can be isolated from blood of normal individuals but lack suppressive function. Hematopoietic peripheral blood stem cell mobilization with G-CSF and GM-CSF enriches for cells phenotypically similar to MDSCs. There is limited data on the role and function of these cells isolated from non-tumor bearing, normal individuals. Recent evidence suggests that graft-versus-host disease (GvHD) can be abrogated in mice by ex vivo expanded, bone marrow derived, MDSCs generated in the presence of GM-CSF, G-CSF and IL-13 (Highfill et al. Blood 2010 116:5738). It remains to be shown whether phenotypic MDSCs identified in non-tumor bearing mice are capable of immune suppression; and, the mechanism by which an immature myeloid cell becomes a functional MDSC remains unknown. We have observed an increase (up to 8 fold) in a population of cells phenotypically resembling monoMDSCs (CD11b+/Ly6C+/Ly6G-) in the spleens and blood of mice mobilized with pegylated-murine-GM-CSF (peg-mGM-CSF). We hypothesized that this population of cells would have suppressive function similar to MDSCs in vitro and in vivo, and may have the potential to abrogate graft-versus-host disease (GvHD). To investigate the function of MDSCs found in spleens of C57/Bl6 (B6) mice treated with peg-mGM-CSF we performed CFSE based anti-CD3/CD28 antibody stimulated T-cell proliferation assays, mixed leukocyte reactions and transwell assays. We observed that CD11b+Ly6C+Ly6G- cells isolated from spleens of mice treated with peg-mGM-CSF have potent suppressive function in vitro that is contact dependent and abrogated by blocking ARG1 or iNOS. This suppressive effect was lost in APC stimulated MLRs using B6 T-cells and Balb/C stimulators (confirmed in two separate experiments). Furthermore, the in vivo potential of these putative MDSCs to abrogate murine GvHD was investigated using a B6 to Balb/C donor leukocyte infusion GvHD model. Adoptive transfer of purified splenic CD11b+Ly6C+Ly6G- cells from peg-mGM-CSF mobilized B6 donors along with an equivalent number of congenic T-cells failed to abrogate GvHD. We investigated timing of MDSC infusion in the B6 to Balb/C GvHD model and found no improvement in weight loss, GvHD score or survival in mice receiving 5×105 monoMDSCs IV on day 1, 6 or 10 after transplant compared to T-cells alone control (n = 5 – 10/group, Log rank, p= NS). To address in vivo function further in a bioluminescent imaging (BLI) tumor model. Balb/C recipients were injected SC with A20 cells mixed +/− monoMDSCs at a 1:10 ratio after lethal irradiation and T-cell deplete bone marrow on day 0. Donor T-cells were infused at day +11. The rate of tumor growth measured by photon flux was the same between subcutaneous tumors either with or without monoMDSCs. (two separate experiments, 5 mice/group). This in vivo data suggested that a critical factor present in vitro might be lacking or insufficient in vivo. To investigate the critical factor(s) present in vitro we performed T-cell proliferation assays in the presence of blocking antibodies against IFNy, TNFalpha, IL-10, GM-CSF and CD154. Only neutralization of IFNy resulted in negation of the suppressive effects of these cells. To investigate the source of IFNy production we used transgenic IFNy knockout mice as T-cell and MDSC donors. Proliferation of IFNy deficient T-cells was suppressed efficiently by wild-type (WT) MDSCs, and, neutralizing IFNy using a blocking antibody negated suppression. This suggested IFNy production by a cell within the putative MDSC sorted population might be critical for MDSC function. IFNy deficient peg-mGM-CSF mobilized CD11b+Ly6C+Ly6G- spleen cells failed to suppress WT or IFNy deficient T-cell proliferation. These results suggest a critical role for IFNy production by CD11b+Ly6C+Ly6G- myeloid cells in maintaining their suppressive phenotype in vitro and perhaps in vivo. Disclosures: No relevant conflicts of interest to declare.

CVX-045: A novel thrombospondin-1 (TSP-1) mimetic CovX-Body that potentiates chemotherapy in preclinical colon cancer models

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 14011-14011 ◽  
Author(s):  
N. J. Levin ◽  
T. A. Leedom ◽  
V. R. Doppalapudi ◽  
L. Li ◽  
J. Lai ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Microvessel Density ◽  
Tumor Model ◽  
Vascular Activity ◽  
Cancer Models ◽  
Tumor Load ◽  
Anti Tumor Activity ◽  
Ht 29

14011 Background: TSP-1 reduces angiogenesis and tumor growth in vivo, and induces endothelial cell apoptosis in vitro. CVX-045 was produced by fusing a peptide derived from TSP-1, known to have anti-vascular activity, to a proprietary monoclonal antibody. CVX-045 possesses the potency and specificity of the TSP-1 mimetic peptide, along with the advantageous PK of an antibody. Methods: Anti-tumor activity of CVX-045 was evaluated in A549, A431, and HT-29 human adenocarcinoma xenograft models. Cells were implanted SC in female nu/nu mice, and tumors were staged to 300–400 mm3 prior to initiation of weekly treatments: CVX-045 IV 10–30 mg/kg; 5-FU or CPT-11 IP 100 mg/kg. Results: CVX-045 (10 mg/kg) significantly reduced A549 and A431 tumor growth 73% (day 49) and 51% (day 22), respectively, but was not effective in the HT-29 xenograft (10 or 30 mg/kg). CVX-045 demonstrated significant anti-vascular activity, reducing tumor microvessel density 51% in A549, 49% in A431, and 36% in HT-29 xenografts. CVX-045 (30 mg/kg) plus 5- FU significantly decreased HT-29 tumor growth 70% and microvessel density 61.2% on day 30 (both P<0.01), effects significantly greater than either agent alone. Co-treatment with CVX-045 (30 mg/kg) plus CPT-11 decreased HT-29 tumor volume 91% on day 28 (P<0.001), also significantly greater than either agent alone. As a surrogate measurement of survival, mice remained on treatment until tumors reached 2000 mm3. CPT-11 alone extended the time to reach tumor load from day 28 to day 39, while the combination of CPT-11 with CVX-045 extended this further to day 60. Conclusions: CVX-045 exhibits significant anti-angiogenic activity in several tumor models and enhances anti-tumor activity in combination with standard chemotherapies in a highly aggressive colon tumor model. No significant financial relationships to disclose.

scholarly journals 848 Novel small molecule HPK1 inhibitor PCC-1 induces strong anti-tumor activity

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A889-A889
Author(s):  
Sanjib Das ◽  
Sravan Mandadi ◽  
Jagmohan Saini ◽  
Sachin Chaudhari ◽  
Ameya Deshpande ◽  
...  
Keyword(s):  
T Cell ◽  
Tumor Growth ◽  
Growth Inhibition ◽  
Small Molecule ◽  
Tumor Model ◽  
Tumor Growth Inhibition ◽  
Target Engagement ◽  
Ct26 Tumor ◽  
Syngeneic Model

BackgroundHematopoietic progenitor kinase 1 (HPK1, MAP4K1), is a negative regulator of T and B cell receptor signaling.1 2 3 A strong anti-tumor immunogenic response and tumor rejection was observed in mice with HPK1 gene knocked out.3 Treatment of HPK1 kinase dead mice with immune check-point blockers (ICBs) demonstrated enhanced tumor growth inhibition.3 Hence, HPK1 is an attractive therapeutic strategy for immuno-oncology based treatment in cancers. In comparison to our previous HPK1 small molecule inhibitor, PCC,4 we present here a differentiated novel HPK1 inhibitor, PCC-1 with good anti-T cell kinases selectivity and stronger anti-tumor efficacy in CT26 tumor model. In addition, using the syngeneic model of MC38 expressing human PD-L1, we present for the first time, the combination efficacy of a HPK1 inhibitor with the clinical ICB, Atezolizumab.MethodsIntuitive medicinal chemistry complemented by structure-based drug design was used to identify & develop potent inhibitors of HPK1 with optimal kinase selectivity, PK and in vivo efficacy profile. The SAR efforts were guided by biochemical assays, functional read-outs and primary human in vitro T-cell activation assays. In vivo target engagement and pharmacodynamic data was generated using CT26 and MC38-hPD-L1 tumor models.ResultsPCC-1 has sub-nanomolar HPK1 inhibition potency and strong target engagement resulting in pSLP76 inhibition, enhanced anti-tumor cytokine production of IL-2 and/or IFNgamma in Jurkat cells, human PBMCs and human whole blood. PCC-1 also demonstrated nanomolar potency in inducing a complete reversal of PGE2 or adenosine mediated immunosuppression. Oral dosing of PCC-1 as a single agent, induced strong tumor growth inhibition (TGI) in the syngeneic model of CT26 and MC38-hPD-L1 tumor models. Combination of PCC-1 with anti-CTLA4 in CT26 tumor model induced significantly greater TGI than anti-CTLA4 alone. Moreover, as a first, the combination of PCC-1 with clinical ICB, Atezolizumab in MC38-hPD-L1 induced enhanced rejection of tumors. These results strongly suggest PCC-1 as a promising candidate for HPK1 inhibition and as a combination partner with ICBs in clinic.ConclusionsPCC-1 is a novel, orally active HPK1 inhibitor that demonstrates excellent stand-alone efficacy and enhances current immunotherapy efficacy. Further evaluation of PCC-1 is ongoing to advance towards clinic.AcknowledgementsWe thank Dnyaneshwar Dahale, Sanjay Patale, Sandip Patil, Vidya Kattige, Jiju Mani, Namrata Singh, Ekta Kashyap, Sandeep Thorat, Pankaj Jain and Pramod Sagar for their contributions to the projectTrial RegistrationN/AReferencesKiefer F, et al. The EMBO Journal 1996.Hu, et al. Genes and Development 1996.Sawasdikosol, Burakoff. eLife 2020;9:e55122.Sachin S Chaudhari, et al. Poster#1709, AACR Annual Meeting April-May 2021.Ethics ApprovalThe studies involving animals have obtained ethics approval from Institutional Animal Ethics Committee (IAEC), The Committee for the Purpose of Control and Supervision of Experiments on Animals (CPCSEA), New Delhi, India, GRC/IAEC/472/2020-1. Participants of the studies have given informed consent before taking part.

Inhibition of B-NHL Tumor Xenografts Following Treatment with Galiximab (Anti-CD80 mAb) and Potentiation When Combined with Chemotherapy

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4873-4873
Author(s):  
Mario I Vega ◽  
Hari Hariharan ◽  
Peter Chu ◽  
Tracey Murphy ◽  
Dana Clanton ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Phase I ◽  
Overall Response Rate ◽  
Response Rate ◽  
Tumor Model ◽  
Chemotherapeutic Drugs ◽  
Overall Response ◽  
Anti Tumor Activity

Abstract Abstract 4873 The non-Hodgkin's lymphomas (NHLs) are a group of lymphoproliferative malignancies with divergent clinical courses. Although the NHLs have historically been treated with radiation therapy and/or chemotherapy, the standard of care has evolved to incorporate the use of rituximab, a mAb that is directed against the CD20 antigen expressed on the surface of transformed B-lymphocytes. However, there are subsets of patients who do not initially respond or become refractory to further treatments. Hence, there is a need for new therapeutic strategies for these patients. CD80 is constitutively expressed on the surface of many B-cell lymphomas. When cell-surface CD80 is cross-linked with anti-CD80 antibodies, cell proliferation is inhibited, proapoptotic molecules are upregulated and antibody-dependent cell cytotoxicity (ADCC) is induced. These findings provide the rationale for using an anti-CD80 mAb to treat lymphoma. Galiximab is a primatized monoclonal antibody that targets CD80 expressed on malignant B cells and is being studied in the clinic as a potential treatment for follicular NHL. Galiximab is a primatized anti-CD80 mAb that has been tested as monotherapy in phase I/II clinical trials involving patients with relapsed/refractory follicular lymphoma (FL), producing an overall response rate of 11% and tumor reductions in 46% of patients. In a recent phase I/II clinical trial involving patients with relapsed or refractory FL, combined therapy with galiximab and rituximab yielded an overall response rate of 66% and a median progression-free survival of 12.1 months at the recommended phase II dose of galiximab (500 mg/m2). We have recently reported that galiximab signals B-NHL cells in vitro and inhibits cell growth and sensitizes resistance tumor cells to apoptosis by chemotherapeutic drugs. The present finding was designed to validate the in vitro findings in in vivo in mice. Thus, we examined in vivo the anti-tumor activity of galiximab used alone and in combination with chemotherapeutic agents in SCID mice bearing human lymphoma xenografts. The in vivo anti-tumor effects of galiximab used alone and in combination with fludarabine or doxorubicin were determined in solid and disseminated human B-lymphoma tumors grown in SCID mice. Galiximab monotherapy in vivo demonstrated significant anti-tumor activity in a Raji lymphoma solid tumor model and in an SKW disseminated lymphoma tumor model. There was significant inhibition in tumor growth and prolongation of survival in both models. In vitro, galiximab sensitized Raji cells to apoptosis by both fludarabine and doxorubicin. Tumor growth inhibition was significantly enhanced when the mice were treated with the combination of galiximab and fludarabine. These findings support the potential clinical application of galiximab in combination with chemotherapeutic drugs for the treatment of CD80-expressing hematologic malignancies. Disclosures: No relevant conflicts of interest to declare.

scholarly journals PAX8 lineage-driven T cell engaging antibody for the treatment of high-grade serous ovarian cancer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Emily Lee ◽  
Sarah Szvetecz ◽  
Ryan Polli ◽  
Angelo Grauel ◽  
Jayson Chen ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Standard Of Care ◽  
Tumor Growth Inhibition ◽  
High Grade ◽  
Ovarian Cancers ◽  
Late Stage Diagnosis ◽  
Anti Tumor Activity

AbstractHigh-grade serous ovarian cancers (HGSOC) represent the most common subtype of ovarian malignancies. Due to the frequency of late-stage diagnosis and high rates of recurrence following standard of care treatments, novel therapies are needed to promote durable responses. We investigated the anti-tumor activity of CD3 T cell engaging bispecific antibodies (TCBs) directed against the PAX8 lineage-driven HGSOC tumor antigen LYPD1 and demonstrated that anti-LYPD1 TCBs induce T cell activation and promote in vivo tumor growth inhibition in LYPD1-expressing HGSOC. To selectively target LYPD1-expressing tumor cells with high expression while sparing cells with low expression, we coupled bivalent low-affinity anti-LYPD1 antigen-binding fragments (Fabs) with the anti-CD3 scFv. In contrast to the monovalent anti-LYPD1 high-affinity TCB (VHP354), the bivalent low-affinity anti-LYPD1 TCB (QZC131) demonstrated antigen density-dependent selectivity and showed tolerability in cynomolgus monkeys at the maximum dose tested of 3 mg/kg. Collectively, these data demonstrate that bivalent TCBs directed against LYPD1 have compelling efficacy and safety profiles to support its use as a treatment for high-grade serous ovarian cancers.

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