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PDF file - 404K, iNGR does not bind to CD13+ monocytes

PDF file - 382K, Peptide description. ID and sequence in single letter amino acid code of each peptide is shown

PDF file - 166K, HUVECs express NGR and CendR motif receptors

Asparagine deamidation in peptides or in fibronectin fragments containing the asparagine-glycine-arginine sequence generates isoaspartate-glycine-arginine (isoDGR), a new αvβ3 integrin-binding motif. Because αvβ3 is expressed in angiogenic vessels, we hypothesized that isoDGR-containing peptides could be exploited as ligands for targeted delivery of drugs to tumor neovasculature. We found that a cyclic CisoDGRC peptide coupled to fluorescent nanoparticles (quantum dots) could bind αvβ3 integrin and colocalize with anti-CD31, anti-αvβ3, and anti-α5β1 antibodies in human renal cell carcinoma tissue sections, indicating that this peptide could efficiently recognize endothelial cells of angiogenic vessels. Using CisoDGRC fused to tumor necrosis factor α (TNF) we observed that ultralow doses (1–10 pg) of this product (called isoDGR-TNF), but not of TNF or CDGRC-TNF fusion protein, were sufficient to induce antitumor effects when administered alone or in combination with chemotherapy to tumor-bearing mice. The antitumor activity of isoDGR-TNF was efficiently inhibited by coadministration with an excess of free CisoDGRC, as expected for ligand-directed targeting mechanisms. These results suggest that isoDGR is a novel tumor vasculature–targeting motif. Peptides containing isoDGR could be exploited as ligands for targeted delivery of drugs, imaging agents, or other compounds to tumor vasculature. [Cancer Res 2008;68(17):7073–82]

Supplementary Figure 1 Legend from Isoaspartate-Glycine-Arginine: A New Tumor Vasculature–Targeting Motif

PDF file - 590K, iNGR penetrates into extravascular tumor tissue

PDF file - 898K, iNGR does not increase the penetration of co-administered Evans blue dye into normal organs

PDF file - 372K, iNGR enhances tumor penetration of Evans Blue dye

PDF file - 1MB, iNGR is cleaved upon entering the cells

PDF file - 517K, iNGR binding is not mediated by alphav integrins

Supplementary Figure 1 from Isoaspartate-Glycine-Arginine: A New Tumor Vasculature–Targeting Motif

Poor penetration of antitumor drugs into the extravascular tumor tissue is often a major factor limiting the efficacy of cancer treatments. Our group has recently described a strategy to enhance tumor penetration of chemotherapeutic drugs through use of iRGD peptide (CRGDK/RGPDC). This peptide comprises two sequence motifs: RGD, which binds to αvβ3/5 integrins on tumor endothelia and tumor cells, and a cryptic CendR motif (R/KXXR/K-OH). Once integrin binding has brought iRGD to the tumor, the peptide is proteolytically cleaved to expose the cryptic CendR motif. The truncated peptide loses affinity for its primary receptor and binds to neuropilin-1, activating a tissue penetration pathway that delivers the peptide along with attached or co-administered payload into the tumor mass. Here, we describe the design of a new tumor-penetrating peptide based on the current knowledge of homing sequences and internalizing receptors. The tumor-homing motif in the new peptide is the NGR sequence, which binds to endothelial CD13. The NGR sequence was placed in the context of a CendR motif (RNGR), and this sequence was embedded in the iRGD framework. The resulting peptide (CRNGRGPDC, iNGR) homed to tumor vessels and penetrated into tumor tissue more effectively than the standard NGR peptide. iNGR induced greater tumor penetration of coupled nanoparticles and co-administered compounds than NGR. Doxorubicin given together with iNGR was significantly more efficacious than the drug alone. These results show that a tumor-specific, tissue-penetrating peptide can be constructed from known sequence elements. This principle may be useful in designing tissue-penetrating peptides for other diseases. Cancer Res; 73(2); 804–12. ©2012 AACR.

Patients with primary central nervous system lymphoma (PCNSL) are treated with high-dose methotrexate-based chemotherapy, which requires hospitalization and extensive expertise to manage related toxicity. The use of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) could overcome these difficulties, but blood-brain barrier (BBB) penetration of related drugs is poor. Tumor necrosis factor-α coupled with NGR (NGR-hTNF), a peptide targeting CD13+ vessels, induces endothelial permeabilization and improves tumor access of cytostatics. We tested the hypothesis that NGR-hTNF can break the BBB, thereby improving penetration and activity of R-CHOP in patients with relapsed/refractory PCNSL (NCT03536039). Patients received six R-CHOP21 courses, alone at the first course and preceded by NGR-hTNF (0.8 μg/m2) afterward. This trial included 2 phases: an “explorative phase” addressing the effect of NGR-hTNF on drug pharmacokinetic parameters and on vessel permeability, assessed by dynamic contrast-enhanced magnetic resonance imaging and 99mTc-diethylene-triamine-pentacetic acid–single-photon emission computed tomography, and the expression of CD13 on tumor tissue; and an “expansion phase” with overall response rate as the primary end point, in which the 2-stage Simon Minimax design was used. At the first stage, if ≥4 responses were observed among 12 patients, the study accrual would have continued (sample size, 28). Herein, we report results of the explorative phase and the first-stage analysis (n = 12). CD13 was expressed in tumor vessels of all cases. NGR-hTNF selectively increased vascular permeability in tumoral/peritumoral areas, without interfering with drug plasma/cerebrospinal fluid concentrations. The NGR-hTNF/R-CHOP combination was well tolerated: there were only 2 serious adverse events, and grade 4 toxicity was almost exclusively hematological, which were resolved without dose reductions or interruptions. NGR-hTNF/R-CHOP was active, with 9 confirmed responses (75%; 95% confidence interval, 51-99), 8 of which were complete. In conclusion, NGR-hTNF/R-CHOP was safe in these heavily pretreated patients. NGR-hTNF enhanced vascular permeability specifically in tumoral/peritumoral areas, which resulted in fast and sustained responses.

Rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) is the standard treatment of diffuse large B-cell lymphoma (DLBCL). Primary DLBCL of the central nervous system (CNS) (primary central nervous system lymphoma [PCNSL]) is an exception because of the low CNS bioavailability of related drugs. NGR–human tumor necrosis factor (NGR-hTNF) targets CD13+ vessels, enhances vascular permeability and CNS access of anticancer drugs, and provides the rationale for the treatment of PCNSL with R-CHOP. Herein, we report activity and safety of R-CHOP preceded by NGR-hTNF in patients with PCNSL relapsed/refractory to high-dose methotrexate-based chemotherapy enrolled in a phase 2 trial. Overall response rate (ORR) was the primary endpoint. A sample size of 28 patients was considered necessary to demonstrate improvement from 30% to 50% ORR. NGR-hTNF/R-CHOP would be declared active if ≥12 responses were recorded. Treatment was well tolerated; there were no cases of unexpected toxicities, dose reductions or interruptions. NGR-hTNF/R-CHOP was active, with confirmed tumor response in 21 patients (75%; 95% confidence interval, 59%-91%), which was complete in 11. Seventeen of the 21 patients with response to treatment received consolidation (ASCT, WBRT, and/or lenalidomide maintenance). At a median follow-up of 21 (range, 14-31) months, 5 patients remained relapse-free and 6 were alive. The activity of NGR-hTNF/R-CHOP is in line with the expression of CD13 in both pericytes and endothelial cells of tumor vessels. High plasma levels of chromogranin A, an NGR-hTNF inhibitor, were associated with proton pump inhibitor use and a lower remission rate, suggesting that these drugs should be avoided during TNF-based therapy. Further research on this innovative approach to CNS lymphomas is warranted. The trial was registered as EudraCT: 2014-001532-11.

The main challenge of adoptive therapy with Chimeric Antigen Receptor modified T cells (CAR T) is the application to the field of solid tumors, where the identification of a proper antigen has emerged as one of the major drawbacks to CAR T cell treatment success. CD44 is a glycoprotein involved in cell-cell and cell-matrix interactions. The isoform containing the variant domain 6 of CD44 gene (CD44v6) has been implicated in tumorigenesis, tumor cell invasion and metastasis and represents an attractive target for CAR T cell therapies. Targeting CD44v6 antigen has been shown to control tumor growth in acute myeloid leukemia and multiple myeloma mouse models. While CAR T approach for the treatment of B cell malignancies has shown great success, response rates among patients with solid cancer are less favorable. The purpose of our study was to test the efficacy of CD44v6.CAR T cells, produced in compliance with Good Manufacturing Practice (GMP), in adenocarcinoma tumor models. We generated a bicistronic retroviral vector containing the CD44v6 CAR and the HSV-TK Mut2 suicide gene to enhance the safety of the proposed CAR T cell therapy. CD44v6 transduced CAR T cells were homogeneously positive for ΔLNGFR selection marker, were enriched in T central memory (TCM) and T memory stem cells (TSCM) and displayed a highly activated phenotype. In vitro assays revealed antigen-specific activation and cytotoxicity of human CD44v6.CAR T cells against CD44v6 expressing tumor cell lines. When infused in immunodeficient tumor bearing mice, human CD44v6.CAR T cells were able to reach, infiltrate and proliferate at tumor sites, finally resulting in tumor growth control. Next, we checked if cells produced in compliance with GMP grade standards retained the same antitumor activity of those produced with research grade materials and protocols. Noteworthy, no differences in the potency of the CAR T obtained with the two manufacturing processes were observed. In conclusion, our preclinical results suggest that CD44v6.CAR T based adoptive therapy could be a promising strategy in solid cancer treatment.

Lentiviral vectors (LVs) are a highly valuable tool for gene transfer currently exploited in basic, applied, and clinical studies. Their optimization is therefore very important for the field of vectorology and gene therapy. A key molecule for LV function is the envelope because it guides cell entry. The most commonly used in transiently produced LVs is the vesicular stomatitis virus glycoprotein (VSV-G) envelope, whose continuous expression is, however, toxic for stable LV producer cells. In contrast, the feline endogenous retroviral RD114-TR envelope is suitable for stable LV manufacturing, being well tolerated by producer cells under constitutive expression. We have previously reported successful, transient and stable production of LVs pseudotyped with RD114-TR for good transduction of T lymphocytes and CD34+ cells. To further improve RD114-TR-pseudotyped LV cell entry by increasing envelope expression, we codon-optimized the RD114-TR open reading frame (ORF). Here we show that, despite the RD114-TRco precursor being produced at a higher level than the wild-type counterpart, it is unexpectedly not duly glycosylated, exported to the cytosol, and processed. Correct cleavage of the precursor in the functional surface and transmembrane subunits is prevented in vivo, and, consequently, the unprocessed precursor is incorporated into LVs, making them inactive.

Background The thymic stromal lymphopoietin (TSLP), a key cytokine for development of Th2 immunity, is produced by cancer associated fibroblasts (CAFs) in pancreatic cancer where predominant tumor infiltrating Th2 over Th1 cells correlates with reduced patients’ survival. Which cells and molecules are mostly relevant in driving TSLP secretion by CAFs in pancreatic cancer is not defined. Methods We performed in vitro, in vivo and ex-vivo analyses. For in vitro studies we used pancreatic cancer cell lines, primary CAFs cultures, and THP1 cells. TSLP secretion by CAFs was used as a read-out system to identify in vitro relevant tumor-derived inflammatory cytokines and molecules. For in vivo studies human pancreatic cancer cells and CAFs were orthotopically injected in immunodeficient mice. For ex-vivo studies immunohistochemistry was performed to detect ASC (apoptosis-associated speck-like protein containing a caspase recruitment domain) expression in surgical samples. Bioinformatics was applied to interrogate published data sets. Results We show in vitro that IL-1α and IL-1β released by pancreatic cancer cells and tumor cell-conditioned macrophages are crucial for TSLP secretion by CAFs. Treatment of immunodeficient mice orthotopically injected with human IL-1 positive pancreatic cancer cells plus CAFs using the IL-1R antagonist anakinra significantly reduced TSLP expression in the tumor. Importantly, we found that pancreatic cancer cells release alarmins, among which ASC, able to induce IL-1β secretion in macrophages. The relevance of ASC was confirmed ex-vivo by its expression in both tumor cells and tumor associated macrophages in pancreatic cancer surgical samples and survival data analyses showing statistically significant inverse correlation between ASC expression and survival in pancreatic cancer patients. Conclusions Our findings indicate that tumor released IL-1α and IL-1β and ASC are key regulators of TSLP secretion by CAFs and their targeting should ultimately dampen Th2 inflammation and improve overall survival in pancreatic cancer. Electronic supplementary material The online version of this article (10.1186/s40425-019-0521-4) contains supplementary material, which is available to authorized users.

Tumor-derived metabolites dampen tumor-infiltrating immune cells and antitumor immune responses. Among the various metabolites produced by tumors, we recently showed that cholesterol oxidized products, namely oxysterols, favor tumor growth through the inhibition of DC migration toward lymphoid organs and by promoting the recruitment of pro-tumor neutrophils within the tumor microenvironment. Here, we tested different drugs capable of blocking cholesterol/oxysterol formation. In particular, we tested efficacy and safety of different administration schedules, and of immunotherapy-based combination of a class of compounds, namely zaragozic acids, which inhibit cholesterol pathway downstream of mevalonate formation, thus leaving intact the formation of the isoprenoids, which are required for the maturation of proteins involved in the immune cell function. We show that zaragozic acids inhibit the in vivo growth of the RMA lymphoma and the Lewis lung carcinoma (LLC) without inducing side effects. Tumor growth inhibition requires an intact immune system, as immunodeficient tumor-bearing mice do not respond to zaragozic acid treatment. Of note, the effect of zaragozic acids is accompanied by a marked reduction in the LXR target genes Abcg1, Mertk, Scd1 and Srebp-1c in the tumor microenvironment. On the other hand, zoledronate, which blocks also isoprenoid formation, did not control the LLC tumor growth. Finally, we show that zaragozic acids potentiate the antitumor effects of active and adoptive immunotherapy, significantly prolonging the overall survival of tumor-bearing mice treated with the combo zaragozic acids and TAA-loaded DCs. This study identifies zaragozic acids as new antitumor compounds exploitable for the treatment of cancer patients.

In the clinic, chimeric antigen receptor-modified T (CAR T) cell therapy is frequently associated with life-threatening cytokine-release syndrome (CRS) and neurotoxicity. Understanding the nature of these pathologies and developing treatments for them are hampered by the lack of appropriate animal models. Herein, we describe a mouse model recapitulating key features of CRS and neurotoxicity. In humanized mice with high leukemia burden, CAR T cell-mediated clearance of cancer triggered high fever and elevated IL-6 levels, which are hallmarks of CRS. Human monocytes were the major source of IL-1 and IL-6 during CRS. Accordingly, the syndrome was prevented by monocyte depletion or by blocking IL-6 receptor with tocilizumab. Nonetheless, tocilizumab failed to protect mice from delayed lethal neurotoxicity, characterized by meningeal inflammation. Instead, the IL-1 receptor antagonist anakinra abolished both CRS and neurotoxicity, resulting in substantially extended leukemia-free survival. These findings offer a therapeutic strategy to tackle neurotoxicity and open new avenues to safer CAR T cell therapies.

NA A major hurdle to the field of allogeneic hematopoietic stem cell transplantation (HSCT) is the lack of validated biomarkers of protective immunity against opportunistic infections, including CMV reactivation syndromes. This issue is particularly relevant to alternative-donor settings, for example, HLA-haploidentical HSCT (haplo-HSCT) and cord blood transplantation, where aggressive GvHD prophylaxis results in a profound and long-lasting state of immune incompetence. Despite the introduction of routine post-transplant viral monitoring and preemptive antiviral therapy, CMV reactivation syndromes remain a major cause of transplant related mortality. Accordingly, serological evidence of prior CMV infection is still one of the main negative prognostic factors in HSCT. Different studies have demonstrated that a faster recovery of CMV-specific T-cell responses associates with a reduced CMV reactivation incidence in HSCT from HLA-identical sibling and matched unrelated donors. Given its clinical and biological peculiarities, it is currently unknown whether these observations are directly translatable to the haplo-HSCT setting. In this study, while aiming to follow the recovery of CMV-specific T-cell responses after haplo-HSCT, we unexpectedly found that protective levels of CMV immunity were associated with a reduced incidence of severe infections overall.

Genetically targeted T cells promise to solve the feasibility and efficacy hurdles of adoptive T-cell therapy for cancer. Selecting a target expressed in multiple-tumor types and that is required for tumor growth would widen disease indications and prevent immune escape caused by the emergence of antigen-loss variants. The adhesive receptor CD44 is broadly expressed in hematologic and epithelial tumors, where it contributes to the cancer stem/initiating phenotype. In this study, silencing of its isoform variant 6 (CD44v6) prevented engraftment of human acute myeloid leukemia (AML) and multiple myeloma (MM) cells in immunocompromised mice. Accordingly, T cells targeted to CD44v6 by means of a chimeric antigen receptor containing a CD28 signaling domain mediated potent antitumor effects against primary AML and MM while sparing normal hematopoietic stem cells and CD44v6-expressing keratinocytes. Importantly, in vitro activation with CD3/CD28 beads and interleukin (IL)-7/IL-15 was required for antitumor efficacy in vivo. Finally, coexpressing a suicide gene enabled fast and efficient pharmacologic ablation of CD44v6-targeted T cells and complete rescue from hyperacute xenogeneic graft-versus-host disease modeling early and generalized toxicity. These results warrant the clinical investigation of suicidal CD44v6-targeted T cells in AML and MM. ""Genetically targeted T cells promise to solve the feasibility and efficacy hurdles of adoptive T-cell therapy for cancer. Selecting a target expressed in multiple-tumor types and that is required for tumor growth would widen disease indications and prevent immune escape caused by the emergence of antigen-loss variants. The adhesive receptor CD44 is broadly expressed in hematologic and epithelial tumors, where it contributes to the cancer stem\\\/initiating phenotype. In this study, silencing of its isoform variant 6 (CD44v6) prevented engraftment of human acute myeloid leukemia (AML) and multiple myeloma (MM) cells in immunocompromised mice. Accordingly, T cells targeted to CD44v6 by means of a chimeric antigen receptor containing a CD28 signaling domain mediated potent antitumor effects against primary AML and MM while sparing normal hematopoietic stem cells and CD44v6-expressing keratinocytes. Importantly, in vitro activation with CD3\\\/CD28 beads and interleukin (IL)-7\\\/IL-15 was required for antitumor efficacy in vivo. Finally, coexpressing a suicide gene enabled fast and efficient pharmacologic ablation of CD44v6-targeted T cells and complete rescue from hyperacute xenogeneic graft-versus-host disease modeling early and generalized toxicity. These results warrant the clinical investigation of suicidal CD44v6-targeted T cells in AML and MM.""

Over the last two decades, several attempts to generate packaging cells for lentiviral vectors (LV) have been made. Despite different technologies, no packaging clone is currently employed in clinical trials. We developed a new strategy for LV stable production based on the HEK-293T progenitor cells; the sequential insertion of the viral genes by integrating vectors; the constitutive expression of the viral components; and the RD114-TR envelope pseudotyping. We generated the intermediate clone PK-7 expressing constitutively gag/pol and rev genes and, by adding tat and rd114-tr genes, the stable packaging cell line RD2-MolPack, which can produce LV carrying any transfer vector (TV). Finally, we obtained the RD2-MolPack-Chim3 producer clone by transducing RD2-MolPack cells with the TV expressing the anti-HIV transgene Chim3. Remarkably, RD114-TR pseudovirions have much higher potency when produced by stable compared with transient technology. Most importantly, comparable transduction efficiency in hematopoietic stem cells (HSC) is obtained with 2-logs less physical particles respect to VSV-G pseudovirions produced by transient transfection. Altogether, RD2-MolPack technology should be considered a valid option for large-scale production of LV to be used in gene therapy protocols employing HSC, resulting in the possibility of downsizing the manufacturing scale by about 10-fold in respect to transient technology.

Poor penetration of antitumor drugs into the extravascular tumor tissue is often a major factor limiting the efficacy of cancer treatments. Our group has recently described a strategy to enhance tumor penetration of chemotherapeutic drugs through use of iRGD peptide (CRGDK/RGPDC). This peptide comprises two sequence motifs: RGD, which binds to αvβ3/5 integrins on tumor endothelia and tumor cells, and a cryptic CendR motif (R/KXXR/K-OH). Once integrin binding has brought iRGD to the tumor, the peptide is proteolytically cleaved to expose the cryptic CendR motif. The truncated peptide loses affinity for its primary receptor and binds to neuropilin-1, activating a tissue penetration pathway that delivers the peptide along with attached or co-administered payload into the tumor mass. Here, we describe the design of a new tumor-penetrating peptide based on the current knowledge of homing sequences and internalizing receptors. The tumor-homing motif in the new peptide is the NGR sequence, which binds to endothelial CD13. The NGR sequence was placed in the context of a CendR motif (RNGR), and this sequence was embedded in the iRGD framework. The resulting peptide (CRNGRGPDC, iNGR) homed to tumor vessels and penetrated into tumor tissue more effectively than the standard NGR peptide. iNGR induced greater tumor penetration of coupled nanoparticles and co-administered compounds than NGR. Doxorubicin given together with iNGR was significantly more efficacious than the drug alone. These results show that a tumor-specific, tissue-penetrating peptide can be constructed from known sequence elements. This principle may be useful in designing tissue-penetrating peptides for other diseases. Cancer Res; 73(2); 804–12. ©2012 AACR.

Cells in the tumor microenvironment may be reprogrammed by tumor-derived metabolites. Cholesterol-oxidized products, namely oxysterols, have been shown to favor tumor growth directly by promoting tumor cell growth and indirectly by dampening antitumor immune responses. However, the cellular and molecular mechanisms governing oxysterol generation within tumor microenvironments remain elusive. We recently showed that tumorderived oxysterols recruit neutrophils endowed with protumoral activities, such as neoangiogenesis. Here, we show that hypoxia inducible factor-1a (HIF-1α) controls the overexpression of the enzyme Cyp46a1, which generates the oxysterol 24-hydroxycholesterol (24S-HC) in a pancreatic neuroendocrine tumor (pNET) model commonly used to study neoangiogenesis. The activation of the HIF-1α-24S-HC axis ultimately leads to the induction of the angiogenic switch through the positioning of proangiogenic neutrophils in proximity to Cyp46a1+islets. Pharmacologic blockade or genetic inactivation of oxysterols controls pNET tumorigenesis by dampening the 24S-HC-neutrophil axis. Finally, we show that in some human pNET samples Cyp46a1 transcripts are overexpressed, which correlate with the HIF-1α target VEGF and with tumor diameter. This study reveals a layer in the angiogenic switch of pNETs and identifies a therapeutic target for pNET patients.

Background: NGR–hTNF exploits the peptide asparagine–glycine–arginine (NGR) for selectively targeting tumour necrosis factor (TNF) to CD13-overexpressing tumour vessels. Maximum-tolerated dose (MTD) of NGR–hTNF was previously established at 45 μg m−2 as 1-h infusion, with dose-limiting toxicity being grade 3 infusion-related reactions. We explored further dose escalation by slowing infusion rate (2-h) and using premedication (paracetamol). Methods: Four patients entered each of 12 dose levels (n=48; 60–325 μg m−2). Pharmacokinetics, soluble TNF receptors (sTNF-R1/sTNF-R2), and volume transfer constant (Ktrans) by dynamic imaging (dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI)) were assessed pre- and post-treatment. Results: Common related toxicity included grade 1/2 chills (58%). Maximum-tolerated dose was not reached. Both Cmax (P

The genetic modification of T cells with a suicide gene grants a mechanism of control of adverse reactions, allowing safe infusion after partially incompatible hematopoietic stem cell transplantation (HSCT). In the TK007 clinical trial, 22 adults with hematologic malignancies experienced a rapid and sustained immune recovery after T cell-depleted HSCT and serial infusions of purified donor T cells expressing the HSV thymidine kinase suicide gene (TK+ cells). After a first wave of circulating TK+ cells, the majority of T cells supporting long-term immune reconstitution did not carry the suicide gene and displayed high numbers of naive lymphocytes, suggesting the thymus-dependent development of T cells, occurring only upon TK+-cell engraftment. Accordingly, after the infusions, we documented an increase in circulating TCR excision circles and CD31(+) recent thymic emigrants and a substantial expansion of the active thymic tissue as shown by chest tomography scans. Interestingly, a peak in the serum level of IL-7 was observed after each infusion of TK+ cells, anticipating the appearance of newly generated T cells. The results of the present study show that the infusion of genetically modified donor T cells after HSCT can drive the recovery of thymic activity in adults, leading to immune reconstitution. (Blood. 2012;120(9):1820-1830) The genetic modification of T cells with a suicide gene grants a mechanism of control of adverse reactions, allowing safe infusion after partially-incompatible Hematopoietic Stem Cell Transplantation (HSCT). In the TK007 clinical trial 22 adults with hematologic malignancies experienced a rapid and sustained immune recovery after T cell-depleted HSCT and serial infusions of purified donor T cells expressing the Herpes Simplex Virus Thymidine Kinase suicide gene (TK(pos) cells). After a first wave of circulating TK(pos) cells, the majority of T cells supporting long-term immune reconstitution did not carry the suicide gene and displayed high numbers of naïve lymphocytes, suggesting the thymus-dependent development of T cells, occurring only upon TK(pos) cell engraftment. Accordingly, after the infusions we documented an increase in circulating T cell Receptor Excision Circles and CD31+ recent thymic emigrants, and a substantial expansion of the active thymic tissue at chest tomography scans. Interestingly, a peak in the serum level of interleukin-7 was observed after each infusion of TK(pos) cells, anticipating the appearance of newly generated T cells. Taken together, our data show that the infusion of genetically modified donor T cells after transplantation can drive the recovery of thymic activity in adults, leading to immune reconstitution.

Background: The NGR-hTNF (asparagine–glycine–arginine–human tumour necrosis factor) is able to promote antitumour immune responses and to improve the intratumoural doxorubicin uptake by selectively damaging tumour blood vessels. Methods: Patients progressing after ⩾1 platinum/taxane-based regimen received NGR-hTNF 0.8 μg m−2 and doxorubicin 60 mg m−2 every 3 weeks. Primary endpoint was a Response Evaluation Criteria in Solid Tumors-defined response rate with a target of more than 6 out of 37 responding patients. Results: A total of 37 patients with platinum-free interval lower than 6 months (PFI

The transfer of high-avidity T cell receptor (TCR) genes isolated from rare tumor-specific lymphocytes into polyclonal T cells is an attractive cancer immunotherapy strategy. However, TCR gene transfer results in competition for surface expression and inappropriate pairing between the exogenous and endogenous TCR chains, resulting in suboptimal activity and potentially harmful unpredicted antigen specificities of the resultant TCRs. We designed zinc-finger nucleases (ZFNs) that promoted the disruption of endogenous TCR beta- and alpha-chain genes. Lymphocytes treated with ZFNs lacked surface expression of CD3-TCR and expanded with the addition of interleukin-7 (IL-7) and IL-15. After lentiviral transfer of a TCR specific for the Wilms tumor 1 (WT1) antigen, these TCR-edited cells expressed the new TCR at high levels, were easily expanded to near purity and were superior at specific antigen recognition compared to donor-matched, unedited TCR-transferred cells. In contrast to unedited TCR-transferred cells, the TCR-edited lymphocytes did not mediate off-target reactivity while maintaining their anti-tumor activity in vivo, thus showing that complete editing of T cell specificity generates tumor-specific lymphocytes with improved biosafety profiles.

In allogeneic hematopoietic cell transplantation (HSCT), donor T lymphocytes mediate the graft-versus-leukemia (GVL) effect, but induce graft-versus-host disease (GVHD). Suicide gene therapy—that is, the genetic induction of a conditional suicide phenotype into donor T cells—allows dissociating the GVL effect from GVHD. Genetic modification with retroviral vectors after CD3 activation reduces T-cell alloreactivity. We recently found that alloreactivity is maintained when CD28 costimulation, IL-7, and IL-15 are added. Herein, we used the minor histocompatibility (mH) antigens HA-1 and H-Y as model alloantigens to directly explore the antileukemia efficacy of human T cells modified with the prototypic suicide gene herpes simplex virus thymidine kinase (tk) after activation with different stimuli. Only in the case of CD28 costimulation, IL-7, and IL-15, the repertoire of tk+ T cells contained HA-1– and H-Y–specific CD8+ cytotoxic T cells (CTL) precursors. Thymidine kinase–positive HA-1– and H-Y–specific CTLs were capable of self-renewal and differentiation into potent antileukemia effectors in vitro, and in vivo in a humanized mouse model. Self-renewal and differentiation coincided with IL-7 receptor expression. These results pave the way to the clinical investigation of T cells modified with a suicide gene after CD28 costimulation, IL-7, and IL-15 for a safe and effective GVL effect.

Purpose: NGR-hTNF exploits the tumor-homing peptide asparagine-glycine-arginine (NGR) for selectively targeting TNF-α to an aminopeptidase N overexpressed on cancer endothelial cells. Preclinical synergism with cisplatin was displayed even at low doses. This study primarily aimed to explore the safety of low-dose NGR-hTNF combined with cisplatin in resistant/refractory malignancies. Secondary aims included pharmacokinetics (PKs), pharmacodynamics, and activity. Experimental Design: NGR-hTNF was escalated using a doubling-dose scheme (0.2–0.4–0.8–1.6 μg/m2) in combination with fixed-dose of cisplatin (80 mg/m2), both given intravenously once every three weeks. PKs and circulating TNF-receptors (sTNF-Rs) were assessed over the first three cycles. Results: Globally, 22 patients (12 pretreated with platinum) received a range of one to ten cycles. Consistently with the low-dose range tested, maximum-tolerated dose was not reached. No dose-limiting toxicities (DLTs) were observed at 0.2 (n = 4) and 0.4 μg/m2 (n = 3). One DLT (grade 3 infusion-related reaction) was observed at 0.8 μg/m2. This dose cohort was expanded to six patients without further DLTs. No DLTs were noted also at 1.6 μg/m2 (n = 3). NGR-hTNF exposure increased dose-proportionally without apparent PK interactions with cisplatin. No shedding of sTNF-Rs was detected up to 0.8 μg/m2. At the dose level of 0.8 μg/m2, expanded to 12 patients for activity assessment, a platinum-pretreated lung cancer patient achieved a partial response lasting more than six months and five patients maintained stable disease for a median time of 5.9 months. Conclusions: The combination of NGR-hTNF 0.8 μg/m2 with cisplatin 80 mg/m2 showed favorable toxicity profile and promising antitumor activity. Clin Cancer Res; 17(7); 1964–72. ©2011 AACR.

Background: The hyaluronate receptor CD44 is a class I membrane glycoprotein overexpressed in hematologic and solid tumors. It plays a role in the bone marrow homing of initiating leukemia cells and in their interactions with the microenvironment. CD44 inhibition drives leukemia cells into differentiation and apoptosis by dislodging them from osteogenic niches (Singh et al, 2013).While CD44 is ubiquitously expressed, the expression pattern of its alternatively spliced isoforms is relatively tumor-restricted. In particular, the isoform variant 6 (CD44v6) has recently emerged as a promising tumor associated antigen. Indeed, it is absent on normal hematopoietic stem cells (HSC) and progenitors, but is expressed on AML and MM, where it correlates with a poor prognosis (Legras et al, 1998; Liebisch et al, 2005). It has been demonstrated that CD44v6 CAR-T cells are able to efficiently kill leukemia and myeloma cells while sparing HSC and keratinocytes, which express low levels of CD44v6 (Casucci et al, 2013; 2018; Norelli et al, 2018). MLM-CAR44.1 is a medicinal product defined as frozen T lymphocytes genetically modified by retroviral transduction to express the CD44v6ΔNL CAR and the herpes simplex virus (HSV)-TK Mut2 suicide gene. This suicide gene was inserted in order to minimize risks of severe toxicities by MLM-CAR44.1. These include predicted monocytopenia and potential cutaneous toxicity, which although not observed in ad hoc mouse model, should be kept under consideration due to CD44v6 expression by keratinocytes. Here we present the first in man phase I-IIa MLM-CAR44.1 clinical protocol we designed to test safety and efficacy of MLM-CAR44.1. This clinical study protocol is Working Package 4 of grant N. 733297 awarded by the European Commission for the action entitled 'EURopean Endeavour for Chimeric Antigen Receptor Therapies - EURE-CART. Methods: The study is a seamless Phase I/IIa, open-label, multicenter clinical trial which combines Phase I dose escalation based on toxicity with Phase IIa dose expansion based on antitumor activity. Target population are patients with relapse/refractory MM or AML who are fit but not candidate to further treatments with a curative intent. Primary objectives of the study are the MLM CAR44.1 maximum tolerated dose (MTD) and safety (phase I) and efficacy (phase IIa). An adaptative Bayesian Optimal Interval (BOIN) design with cohorts of 3 patients for each indication (AML and MM) was chosen to identify the MTD, based on a target toxicity rate of 30% and an interval of 25% - 35%. This schema was preferred to minimize the decision errors of dose assignment and to safeguard patient ethics and safety by allowing decisions to be made at any time during the study. Results: Patients will be enrolled if they have relapsed/refractory AML unlikely to benefit of further cytotoxic therapy and not candidate to allogeneic bone marrow transplantation (allo) or MM after at least 4 different prior treatments in 3 treatment lines, or 4 treatments in 2 treatment lines in case of early relapsing patients (relapse in less than 1.5 years) and an adequate organ function. Previous allo is an exclusion criteria. MLM-CAR44.1 will be infused after lymphodepleting chemotherapy. Primary endpoints of safety will be evaluated 30 days after MLM-CAR44.1 infusion. Up to 15 MM and 15 AML patients are expected for completing phase I. Primary endpoint of efficacy will be evaluated at 2 and 3 months for AML and MM, respectively. Pediatric population will start to be included into the trial only after a successful phase I in adults. Conclusion: Study is expected to open in the 4th quarter 2018 with first patient MLM-CAR44.1 infusion by the end of 2018. An update on study and enrollment status will be provided during the meeting. Disclosures Hajek: Takeda: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding. Locatelli:Bellicum: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Miltenyi: Honoraria; bluebird bio: Consultancy. Bordignon:MolMed: Employment. Traversari:Molecular Medicine spa: Employment.

Background NGR-hTNF consists of human tumour necrosis factor (hTNF) fused with the tumour-homing peptide Asp-Gly-Arg (NGR), which is able to selectively bind an aminopeptidase N overexpressed on tumour blood vessels. Preclinical antitumour activity was observed even at low doses. We evaluated the activity and safety of low-dose NGR-hTNF in colorectal cancer (CRC) patients failing standard therapies. Patients and methods Thirty-three patients with progressive disease at study entry received NGR-hTNF 0.8μg/m 2 given intravenously every 3weeks. The median number of prior treatment regimens was three (range, 2–5). One-quarter of patients had previously received four or more regimens and two-thirds targeted agents. Progression-free survival (PFS) was the primary study objective. Results NGR-hTNF was well tolerated. No treatment-related grade 3 to 4 toxicities were detected, most common grade 1 to 2 adverse events being short-lived, infusion-time related chills (50.0%). One partial response and 12 stable diseases were observed, yielding a disease control rate of 39.4% (95% CI, 22.9–57.8%). Median PFS and overall survival were 2.5months (95% CI, 2.1–2.8) and 13.1months (95% CI, 8.9–17.3), respectively; whereas in patients who achieved disease control the median PFS and overall survival were 3.8 and 15.4months, respectively. In an additional cohort of 13 patients treated at same dose with a weekly schedule, there was no increased toxicity and 2 patients experienced PFS longer than 10months. Conclusion Based on tolerability and preliminary evidence of disease control in heavily pretreated CRC patients, NGR-hTNF deserves further evaluation in combination with standard chemotherapy.

Background: asparagine-glycine-arginine-human tumour necrosis factor (NGR-hTNF), an agent selectively damaging the tumour vasculature, showed a biphasic dose–response curve in preclinical models. Previous phase I trials of NGR-hTNF indicated 0.8 and 45 μg/m2 as optimal biological and maximum-tolerated dose, respectively. Patients and methods: Two sequential cohorts of 12 colorectal cancer (CRC) patients who had failed standard therapies received NGR-hTNF 0.8 or 45 μg/m2 in combination with capecitabine–oxaliplatin (XELOX). Results: Median number of prior treatment lines was 3 in the low-dose and 2 in the high-dose cohort. Overall, 21 patients had been pretreated with oxaliplatin-based regimens. No grade 3–4 NGR-hTNF-related toxicities were observed. Grade 1–2 chills were reported in 43% and 40% of cycles in the low-dose and high-dose cohorts, respectively. In the low-dose cohort, one patient achieved a partial response and five had stable disease for a median of 4.6 months. In the high-dose cohort, six patients had stable disease for a median of 3.6 months. Three-month progression-free survival (PFS) rates were 50% and 33% in the low-dose and high-dose cohort, respectively. Three patients in low-dose cohort experienced PFS longer than PFS on last prior therapy. Conclusions: Both NGR-hTNF doses were safely combined with XELOX in pretreated CRC patients. Hint of activity was apparent only with low-dose NGR-hTNF.

7575Background: PCNSL pts are treated with HDMTX-based chemo, which requires hospitalization and extensive expertise to manage toxicity. R-CHOP could overcome these troubles, but CNS access of rela...

Purpose NGR-hTNF consists of human tumor necrosis factor α (hTNF-α) fused to the tumor-homing peptide asparagine-glycine-arginine (NGR) able to selectively bind an aminopeptidase N isoform overexpressed on tumor blood vessels. Hypervascularity is a prominent and poor-prognosis feature of malignant pleural mesothelioma (MPM). Currently, there are no standard options for patients with MPM who are failing a front-line pemetrexed-based regimen. We explored safety and efficacy of NGR-hTNF in this setting. Patients and Methods Eligible patients had radiologically documented tumor progression and performance status ≤ 2. Primary study aim was progression-free survival (PFS). NGR-hTNF 0.8 μg/m2 was given intravenously every 3 weeks. A subsequent cohort of patients received 0.8 μg/m2 on a weekly basis. Results In the triweekly cohort (n = 43), only one grade 3 drug-related toxicity was noted, and the most common grades 1 to 2 were short-lived chills (71%). The median PFS was 2.8 months (95% CI, 2.3 to 3.3 months). Nineteen patients (44%) had disease control (one had partial response, and 18 had stable diseases) and experienced a median progression-free time of 4.4 months. In the weekly cohort (n = 14), there was no higher toxicity, and median PFS was 3.0 months (95% CI, 1.9 to 4.1 months). Seven patients (50%) had disease control (all stable diseases) and had a median progression-free interval of 9.1 months. In the overall study population (N = 57), median PFS was 2.8 months. Median progression-free time was 4.7 months in twenty-six patients (46%) who achieved disease control. Median survival was 12.1 months. Conclusion The tolerability and disease control of NGR-hTNF 0.8 μg/m2 weekly warrant additional evaluation in patients with advanced MPM.

Recent advances in cancer therapy include the design ofmolecules that interfer with tumor angiogenesis and moietiesthat recognize specific receptors expressed onto the tumorendothelium and/or onto tumor cells, thus allowing theligand-directed targeted delivery of various drugs and par-ticles to tumors. In this context, integrin avb3 and themembrane-spanning surface protein aminopeptidase N(CD13) play a pivotal role in tumor growth and metastaticspread, as they are important membrane-bound receptorshighly expressed during angiogenesis.

Objectives: To describe the first in-depth analysis of both the T-cell responses against human herpesvirus-8 (HHV-8) and the HHV-8 viral load in 1 patient who developed iatrogenic HHV-8-associated-Kaposi's sarcoma (KS) following immunosuppressive treatment for undifferentiated arthritis and to review the literature on iatrogenic KS (IKS). Methods: T-cell responses against HHV-8 lytic and latent antigens were analyzed by ex vivo enzyme-linked immunospot (Elispot) and HHV-8 viral load was assessed by quantitative polymerase chain reaction, in sequential peripheral blood samples from a 55-year-old woman who developed skin/mucosal and visceral KS, while receiving treatment with cyclosporine, methotrexate, and methylprednisolone for undifferentiated arthritis. Results: KS may result from HHV-8 infection in patients undergoing immunosuppressive treatment for rheumatic diseases and this is the first case of IKS occurring in undifferentiated arthritis. A role for immune surveillance in the pathogenesis of IKS is supported by the observation of disease regression following discontinuation of immunosuppressive therapy. In a 4-year follow-up, we showed that variations of the virus-specific immune responses but not of the viral load correlated well with the disease course, characterized by 2 remission and subsequent relapse phases, following changes of immunosuppressive therapy. Conclusions: We have provided evidence of a clear-cut correlation between changes in immunologic markers of HHV-8 infection and the disease course of this viral associated tumor, concomitant with variations of immunosuppressive treatment. Thus, ex vivo enzyme-linked immunospot for HHV-8-specific T-cell responses represents a new tool for the clinical management of rheumatic patients with IKS. (C) 2009 Elsevier Inc. All rights reserved. Semin Arthritis Rheum 39:170-175 RI Rossi, Giulio/C-5576-2011