Induced Tumor Lysis Research Articles

Abstract 1325: CD19 CAR-expressing iPSC-derived NK cells effectively enhance migration and cytotoxicity into glioblastoma by targeting to the pericytes in tumor microenvironment

Abstract In cancer immunotherapy, targeting specific antigens with chimeric antigen receptors (CARs) has emerged as a potent tool for cell-based therapy. After being accessed by CARs, the selective anticancer lysis by CAR-natural killer (NK) cells through ‘missing-self’ and ‘induced-self’ mechanisms can mitigate off-tumor toxicity, a contrast to CAR-T cells. This specificity can be advantageous in the heterogeneous milieu of solid tumors. In the tumor microenvironment of glioblastoma (GBM), pericytes not only support tumor growth but also contribute to immune evasion, underscoring their potential as therapeutic targets in GBM treatment. Indeed, we examined and observed the presence of CD19-positive pericytes derived from GBM in patient samples, particularly within the perivascular niche, highlighting CD19 as a possible therapeutic target. Given this context, our study aimed to target the GBM tumor microenvironment, with a special focus on pericytes expressing CD19, to evaluate the potential effectiveness of CD19 CAR-iNK cells against GBM. In this study, we generated induced pluripotent stem cell-derived NK (iNK) cells with CD19 CAR. To determine whether CD19 CAR targets the tumor microenvironment pericytes in GBM, we developed GBM-blood vessel assembloids (GBVA) by fusing GBM spheroids with blood vessel organoids. When co-cultured with GBVA, CD19 CAR-iNK cells migrated towards the pericytes surrounding the GBM, inducing tumor lysis through NKp44 upregulation. Using a microfluidic chip, we observed that post-infused CD19 CAR-iNK cells targeted pericytes in a perfusion-like setting, facilitating an examination of CD19 CAR-driven migration and their tumor-specific cytotoxicity on the GBM. Therefore, we conclude that CD19 CAR-iNK cells may effectively target the pericytes in the GBM tumor microenvironment, suggesting their potential therapeutic value for GBM treatment. Citation Format: Dasom Kong, Daekee Kwon, Bokyung Moon, Da-Hyun Kim, Kyung-Sun Kang. CD19 CAR-expressing iPSC-derived NK cells effectively enhance migration and cytotoxicity into glioblastoma by targeting to the pericytes in tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1325.

Abstract 6705: A novel tri-specific T cell engager targeting the intracellular oncoprotein WT1

Abstract Background: Wilms' tumor gene 1 (WT1) is considered an oncogenic factor, with high expression observed in several hematological malignancies and solid tumors. However, its expression is rarely found in normal adult tissue. WT1 can be degraded by the proteasome, processed and presented on the cell surface as major histocompatibility complex (MHC) I epitopes and recognized by T cell receptors (TCR). Here, we described the development of WT1-TOPAbody, a novel tri-specific T cell engager (TCE), that activated T cells by both CD3 and 4-1BB signaling upon recognition of WT1 in the context of HLA-A02, leading to superior anti-tumor efficacy. Materials and Methods: WT1-TOPAbody was evaluated for its antigen binding activity and target specificity by a series protein/peptide and cell-based assays. In vitro cytotoxicity and T cell activation mediated by WT1-TOPAbody was further assessed in a panel of WT1+ tumor cell lines in coculture with effector cells. Anti-tumor activity was investigated in a humanized syngeneic mice model bearing WT1/HLA-A02 expressing tumors. Safety assessment including cytokine release assay (CRA) and preliminary CMC developability was also performed. Results: WT1-TOPAbody exhibited superior binding affinity to the WT1/HLA-A02 complex while displaying lower binding to off-target peptides and CD34+ HSC from healthy donor than clinical benchmark WT1-CD3 bispecific antibody, RG-6007. WT1-TOPAbody effectively induced tumor lysis in multiple WT1+ tumors including leukemia, ovarian, breast, and colon cancer cells. Moreover, serial killing of tumor cells were observed in WT1-TOPAbody treated T cells, accompanied by lower exhaustion markers expressed, suggesting a prolonged anti-tumor inhibition effect of WT1-TOPAbody. In a humanized CD3e/4-1BB/HLA-A2.1 mouse model, WT1-TOPAbody significantly inhibited tumor growth in a dose-dependent manner and the efficacy was superior than that of the benchmark. Additionally, IL-6 release was minimal in PBMC upon treatment of the antibody, indicating a reduced risk of inducing cytokine release syndrome (CRS). Drug developability assessment indicated that the leading WT1-TOPAbody was a reasonably developable molecule to be taken forward. Conclusion: WT1-TOPAbody is a differentiated WT1/HLA-A02 targeted T cell engagers that displayed potent and durable anti-tumor activity. These results collectively support the potential of WT1-TOPAbody as a novel therapeutic agent against WT1/HLA-A02+ cancers and warrant its further development. Citation Format: Shan Gao, Liu Yang, Jun Du, Wenqing Jiang, Lei Fang. A novel tri-specific T cell engager targeting the intracellular oncoprotein WT1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6705.

PAX5 Epigenetically Orchestrates CD58 Transcription and Modulates Blinatumomab Response in Acute Lymphoblastic Leukemia

Blinatumomab is a bi-specific molecule that engages CD3+ T cells with CD19-expressing malignant B cells, thus inducing tumor lysis by T-cell immune response. While large frontline ALL trials of blinatumomab are lacking, existing data strongly indicate substantial inter-patient variability in response and toxicities. Complete remission rate ranges from 36 to 66%, depending on the regimen used and patient characteristics. Moreover, the duration of remission varies among trials, with a significant proportion of patients experiencing relapse or progressive disease following blinatumomab treatment, raising concerns about acquired drug resistance. In particular, mechanisms of resistance in CD19+ relapse remain largely unclear. Using genome-wide CRISPR screen in B-ALL cell line in vitro, we comprehensively identified leukemia intrinsic factors of blinatumomab sensitivity. In addition to CD19 deletion the loss of CD58 emerged as a top driver for resistance, plausibly compromising the CD2-CD58-mediated interaction between T cells and B-ALL. Genomic editing of the CD58 gene or blocking with anti-CD58 antibody completely abrogated blinatumomab sensitivity across different B-ALL cell lines. Screening 1,639 transcription factor genes, we then identified PAX5 as the key activator of CD58. Interestingly, primary ALL samples with PAX5 P80R mutation also showed complete loss of CD58 expression, based on RNA-seq of 1,988 B-ALL samples across 20 molecular subtypes. To further validate this, we developed isogenic clones of the B-ALL cell line 697, with different PAX5 diplotypes: wildtype/wildtype (WT/WT), wildtype/frameshift (WT/fs), and P80R/frameshift (P80R/fs). P80R/fs and WT/fs clones exhibited significantly lower CD58 expression as compared to the WT/WT clone, and both were markedly resistant to blinatumomab. PAX5 mutation did not influence CD19 expression in these B-ALL cells. By testing a panel of primary ALL samples in vitro, we found that blast harboring the PAX5 P80R mutation has the lowest CD58 expression and was the most resistant to blinatumomab, which was reversed by ectopic expression of CD58. To delineate the mechanism by which PAX5 mutation affects CD58 suppression in ALL, we comprehensively profiled epigenomic marks within the CD58 locus in 697 cells with WT/fs, P80R/fs, and WT/WT genotypes. Using ChIP-seq, we identified PAX5 binding sites within Intron 1 of the CD58 genes. By contrast, PAX5 binding at this locus was decreased in WT/fs cells and completely eliminated in the P80R/fs clones, suggesting a loss-of-function effect of the P80R mutation. This region was also characterized by H3K27ac and H3K4me3 marks, signifying its enhancer activity, which was also lost in P80R/fs cells. ATAC-seq profiling of these samples showed a similar pattern of PAX5-dependent open chromatin status. CRISPR interference showed that blocking the genomic sequence encompassing this enhancer resulted in significant downregulation of CD58 expression. PAX5 binding was also observed in the CD19 promoter region, but P80R mutation had only modest effects on histone modification and chromatin accessibility at this locus. Finally, we explored the effects of CD58 loss on T cell activation. T cell cocultured with CD58KO Nalm6 clone showed a substantial decrease in activation and proliferation, as compared to that cocultured with parental Nalm6. Defects of activation and proliferation were also observed in T cells cocultured with PAX5 P80R/fs 697 clone as compared to those with parental 697. Using RNA-seq, we identified 111 genes that were highly expressed in T cells cocultured with parental (relative to those with CD58KO Nalm6). Among these hits, there was significant enrichment of genes involved in oxygen metabolisms, immune response, and cytokine signaling pathways, indicating the loss of CD58 abolished blinatumomab-induced T cell activation. ATAC-seq of these samples further confirmed the findings of RNA-seq studies. In conclusion, our study identified the critical role of CD58-mediated interaction between B-ALL and T cells for blinatumomab sensitivity in this type of leukemia, pointing to potential strategies for genomics-guided blinatumomab treatment individualization.

Exploitation of treatment induced tumor lysis to enhance the sensitivity of ctDNA analysis: A first-in-human pilot study

IntroductionBlood-based liquid biopsies examining circulating tumour DNA (ctDNA) have increasing applications in non-small cell lung cancer (NSCLC). Limitations in sensitivity remain a barrier to ctDNA replacing tissue-based testing. We hypothesized that testing immediately after starting treatment would yield an increased abundance of ctDNA in plasma because of tumor lysis, allowing for the detection of genetic alterations that were occult in baseline testing. MethodsThree prospective cohorts of patients with stage III/IV NSCLC were enrolled. Cohort 1 (C1) contained patients starting platinum doublet chemoradiation (n = 10) and cohort 2 (C2) initiating platinum doublet cytotoxic chemotherapy ± immunotherapy (n = 10). Cohort 3 (C3) contained patients receiving palliative radiation. Two baseline samples were collected. In C1 and C2, subsequent samples were collected 3, 6, 24 and 48 h post initiation of chemotherapy. Patients in C3 had samples collected immediately prior to the next three radiotherapy fractions. Samples were analyzed for ctDNA using the 36-gene amplicon-based NGS Inivata InVisionFirst®-Lung assay. ResultsA total of 40 patients were enrolled. Detectable ctDNA was present at baseline in 32 patients (80%), 4 additional patients (50%) had detectable ctDNA in post-treatment samples. Seven patients with detectable ctDNA at baseline (23%) had new genetic alterations detected in post-treatment samples. Mutant molecule numbers increased with treatment in 24 of 31 (77%) pts with detectable ctDNA. ctDNA levels peaked a median of 7 h (IQR:2–26 h) after the initiation of chemotherapy and a median of 2 days (IQR:1–3 days) after radiation was commenced. ConclusionctDNA levels increase in the hours to days after starting treatment. ctDNA testing in the acute post-treatment phase can yield results that were not evident in pre-treatment testing. Application of this principle could improve ctDNA utility as an alternate to tissue-based testing and improve sensitivity for the detection of treatment-resistant clones.(NCT03986463).

Assessment of Tumor Lysis Syndrome in Patients with Chronic Lymphocytic Leukemia Treated with Venetoclax in the Clinical Trial and Post-Marketing Settings

Assessment of Tumor Lysis Syndrome in Patients with Chronic Lymphocytic Leukemia Treated with Venetoclax in the Clinical Trial and Post-Marketing Settings

Abstract 770: Exploitation of treatment induced tumor lysis to enhance sensitivity of ctDNA analysis: a first-in-human pilot study

Abstract Background: Blood based liquid biopsies examining circulating tumour DNA (ctDNA) have increasing applications in non-small cell lung cancer (NSCLC). Limitations in sensitivity, especially in patients with limited disease burden, remains a barrier to ctDNA replacing tissue-based testing. There is a paucity of data regarding the optimal time to measure ctDNA, specifically the dynamics of ctDNA levels in the hours to days following a new and effective treatment. We hypothesize that chemotherapy or radiation will yield an increased abundance of ctDNA in plasma by inducing tumor lysis, allowing for the detection of genetic alterations that were occult in baseline testing. Methods: Two prospective cohorts of twenty patients (pts) with stage III/IV NSCLC were enrolled. Cohort 1 (C1) contained patients starting the first cycle of platinum doublet chemoradiation (C1a, n=10) or the first cycle of platinum doublet cytotoxic chemotherapy ± immunotherapy without concurrent radiation (C1b, n=10). Cohort 2 (C2) contained patients receiving palliative radiation. Consenting patients provided baseline samples, the first ≤ 14 days prior to starting treatment and one immediately prior to treatment. In C1, subsequent samples were collected (A) 2-3, (B) 4-6, (C) 18-72 and (D) 42-96 hours post initiation of chemotherapy. Pts in C2 had samples collected immediately prior to radiotherapy fractions 2, 3, and 4. Samples were analyzed for ctDNA using the 36-gene amplicon-based NGS Inivata InVisionFirst®-Lung assay. Results: Complete results were available for the first 28 of 40 enrolled pts, C1a - 8 pts, C1b - 8 pts, C2 - 12 pts. Detectable ctDNA was present at baseline in 21 pts (75%), 4 additional pts (14.3%) had detectable ctDNA in post treatment samples (C1a - 2pts, C1b - 1pt, C2 - 1pt). Three of the patients with detectable ctDNA at baseline (10.7%) had new genetic alterations detected in post treatment samples. A total of 7/28 pts (25%) had new genetic alterations detected in the post treatment samples. Mutant molecule numbers increased with treatment in 19 of 25 (76%) pts with detectable ctDNA, C1 - 11 of 15 pts (73.3%) and C2 - 8 of 10 pts (80%). ctDNA levels peaked a median of 2.2 hours (interquartile range (IQR): 1.5 - 2.9 hours) after the initiation of chemotherapy and a median of 1 day (IQR: 1-2 days) after radiation was commenced. The percentage increase in ctDNA levels was a median of 39.3% (IQR: -20.5 to +112.8%) in C1, with median increases of 22.0% and 39.3% in C1a and C1b, respectively. C2 had a median increase of 81.9% (IQR: 0 to +161.5%). Conclusion: ctDNA levels increase in the hours to days after starting a new treatment. ctDNA testing in the acute post treatment phase can yield results that were not evident in pretreatment testing. Application of this principle could improve ctDNA utility as an alternate to tissue-based testing and/or improve sensitivity for the detection of treatment-resistant clones. Citation Format: Daniel Breadner, Mark David Vincent, Rohann Correa, Morgan Black, Andrew Warner, Melody Qu, Diane Logan, Michael Sanatani, Jawaid Younus, Brian Yaremko, George Rodrigues, Phillip Blanchette, Joanna Laba, Edward Yu, David Goodale, Lori Lowes, Vasudeva Bhat, Albert Gratton, James Sinfield, Susan Archer, Clive Morris, Emma Green, Greg Jones, Alison Allan, David Palma, Jacques Raphael. Exploitation of treatment induced tumor lysis to enhance sensitivity of ctDNA analysis: a first-in-human pilot study [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 770.

Exploitation of treatment induced tumor lysis to enhance sensitivity of ctDNA analysis: A first-in-human pilot study.

3530 Background: Blood based liquid biopsies examining circulating tumour DNA (ctDNA) have increasing applications in non-small cell lung cancer (NSCLC). Limitations in sensitivity remains a barrier to ctDNA replacing tissue-based testing. There is a paucity of data regarding the dynamics of ctDNA levels in the hours to days following a new treatment. We hypothesize that chemotherapy or radiation will yield an increased abundance of ctDNA in plasma by inducing tumor lysis, allowing for the detection of genetic alterations that were occult in baseline testing. Methods: Two prospective cohorts of 20 patients (pts) with stage III/IV NSCLC were enrolled. Cohort 1 (C1) contained pts starting the first cycle of platinum doublet chemoradiation (C1a, n=10) or the first cycle of platinum doublet cytotoxic chemotherapy ± immunotherapy without radiation (RT) (C1b, n=10). Cohort 2 (C2) contained pts receiving palliative RT alone. Two baseline samples were collected, the first ≤ 14 days prior to starting treatment and one immediately prior to treatment. In C1, subsequent samples were collected 3, 6, 24 and 48 hours post initiation of chemotherapy. Pts in C2 had samples collected immediately prior to RT fractions 2, 3, and 4. Samples were analyzed for ctDNA using the 36-gene amplicon-based NGS Inivata InVisionFirst-Lung assay. Results: Complete results were available for the first 35 of 40 enrolled pts, C1a – 10 pts, C1b – 9 pts, C2 – 16 pts. Detectable ctDNA was present at baseline in 27 pts (77%), 4 additional pts (11%) had detectable ctDNA in post treatment samples. Four of the patients with detectable ctDNA at baseline (15%) had new genetic alterations detected in post treatment samples. A total of 8/35 pts (23%) had new genetic alterations detected in the post treatment samples. Mutant molecule numbers increased with treatment in 23 of 31 (74%) pts with detectable ctDNA, C1 - 13 of 19 pts (68%) and C2 - 10 of 16 pts (63%). ctDNA levels peaked a median of 2.2 hours (IQR: 1.5 – 2.9 hours) after the initiation of chemotherapy and a median of 1 day (IQR: 1-2 days) after radiation was commenced. The percentage increase in ctDNA levels was a median of 29% (IQR: -18 to +112%) in C1. C2 had a median increase of 16% (IQR: 0 to +131%). Conclusions: ctDNA levels increase in the hours to days after starting treatment. ctDNA testing in the acute post treatment phase can yield results that were not evident in pretreatment testing. Application of this principle could improve ctDNA utility as an alternate to tissue-based testing and improve sensitivity for the detection of treatment-resistant clones.

Oncolytic Viruses Engineered to Enforce Leptin Expression Reprogram Tumor-Infiltrating T Cell Metabolism and Promote Tumor Clearance

Immunotherapy can reinvigorate dormant responses to cancer, but response rates remain low. Oncolytic viruses, which replicate in cancer cells, induce tumor lysis and immune priming, but their immune consequences are unclear. We profiled the infiltrate of aggressive melanomas induced by oncolytic Vaccinia virus using RNA sequencing and found substantial remodeling of the tumor microenvironment, dominated by effector Tcell influx. However, responses to oncolytic viruses were incomplete due to metabolic insufficiencies induced by the tumor microenvironment. We identified the adipokine leptin as a potent metabolic reprogramming agent that supported antitumor responses. Leptin metabolically reprogrammed Tcells invitro, and melanoma cells expressing leptin were immunologically controlled in mice. Engineering oncolytic viruses to express leptin in tumor cells induced complete responses in tumor-bearing mice and supported memory development in the tumor infiltrate. Thus, leptin can provide metabolic support to tumor immunity, and oncolytic viruses represent a platform to deliver metabolic therapy.

Carfilzomib Induced Tumor Lysis Syndrome and Other Adverse Events

In the area of multiple myeloma (MM) therapy, proteasome inhibitors (PI) have emerged with promising responses both in the first- and second-line setting. Carfilzomib (CFZ) is a second-generation, selective PI approved in 2012 for the treatment of relapsed/refractory multiple myeloma (RRMM) in patients who received 2 prior therapies or have evidence of disease progression within 60 days of completion of last therapy. Its safety profile reported adverse events (AEs) ranging from drug-related AEs (nausea and vomiting), hematologic AEs (neutropenia and thrombocytopenia), and nonhematologic AEs (electrolyte imbalances). As CFZ use is gaining popularity, various hematological, renal, cardiovascular, pulmonary, and neurological toxicities have been reported. We are presenting this case to describe a rare occurrence of tumor lysis syndrome (TLS) with the use of this novel targeted therapy.

CD20 Tcb (RG6026), a Novel "2:1" T Cell Bispecific Antibody for the Treatment of B Cell Malignancies

Despite the recent advancements in treatment options with the introduction of anti-CD20 monoclonal antibody therapy, approximately 50% of patients with non-Hodgkin's lymphomas (NHL) will not sustain a durable response to standard of care (SOC) treatment. Thus, there remains a continuous need for safer and more effective anti-cancer therapies in this indication. T-cell bispecific antibodies (TCBs) represent a new class of disease targeting agents shown to promote the activation of a patient's own T cells to attack and kill cancer cells. CD20 TCB is a new bispecific antibody with IgG-like pharmacokinetic properties whose unique "2:1" structure leads to increased tumor antigen avidity, T cell activation, and tumor cell killing, as compared to other T cell engaging bispecific antibody molecular formats. The molecule comprises two CD20 binding Fabs (derived from the Type II CD20 IgG1 obinutuzumab), one CD3e binding Fab (fused to one of the CD20 Fabs via a short flexible linker), and an engineered, heterodimeric Fc region with completely abolished binding to FcgRs and C1q.In vitro, CD20 TCB was shown to dose-dependently induce tumor lysis with EC50 values in the range of 0.05 - 3.1 pM. The "2:1"format of CD20 TCB was shown to confer superior potency (up to 10 - 1000x) when compared to CD20 TCBs having the conventional "1:1" IgG-based format (i.e., one binding domain for CD20 and one for CD3). CD20 TCB-mediated tumor lysis resulted in T-cell activation, proliferation and cytokine release with up-regulation of programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) axis upon tumor lysis.CD20 TCB also demonstrated potent ex vivo activity in whole bone marrow aspirate samples of NHL and CLL patients (n=17). Such primary tumor samples preserve the native tumor microenvironment and bear low effector to target cell ratios ranging in this study from 0.02 to 0.8 (average value 0.3). CD20 TCB activity was consistently superior to that of the "1:1" CD20 TCB and demonstrated faster, more profound and more potent B cell depletion with EC50 values ranging from 0.002 to 2.7 nM.In vivo, CD20 TCB displayed potent anti-tumor activity in xenograft models in stem cell humanized mice and induced regression of large, aggressive WSU-DLCL2 lymphoma tumors (0.5 mg/kg, weekly administration). In addition to tumor regression, CD20 TCB treatment led to fast and complete elimination of peripheral blood B cells within 24 h after the first administration (0.05, 0.15 and 0.5 mg/kg, weekly administration) and to a complete elimination of B cells in spleen, bone marrow and lymph nodes after two administrations. B cell depletion was paralleled by transient decrease of T-cell counts in the peripheral blood and by the peak of cytokine release 24 h after the first administration, followed by rapid recovery and return to baseline levels at 72 h post treatment. Tumor growth inhibition mediated by CD20 TCB was accompanied by increase in intra-tumor T-cell infiltration, up-regulation of PD-1 receptor on T cells and PD-L1 in the tumor. Combination studies of CD20 TCB with PD-L1 blocking antibody led to more profound and faster tumor growth inhibition.Taken together, the preclinical data show that CD20 TCB is a novel differentiated CD20-targeting T cell bispecific antibody with promising anti-tumor activity and the ability to modify the tumor microenvironment. CD20 TCB consistently demonstrated superior potency compared to other CD20 TCBs with a conventional "1:1" IgG format. This translated into superior efficacy in vitro, ex-vivo and in vivo, which could not be matched by increasing doses of the "1:1" TCBs. The molecule is now scheduled to start clinical trial by December 2016. DisclosuresBacac:Roche: Employment, Equity Ownership, Patents & Royalties. Umaña:Roche: Employment, Equity Ownership, Patents & Royalties. Herter:Roche: Employment, Patents & Royalties. Colombetti:Roche: Employment. Sam:Roche: Employment. Le Clech:Roche: Employment. Freimoser-Grundschober:Roche: Employment. Richard:Roche: Employment. Nicolini:Roche: Employment. Gerdes:Roche: Employment. Lariviere:Roche: Employment. Neumann:Roche: Employment. Klein:Roche: Employment, Patents & Royalties.

Imatinib Induced Tumor Lysis Syndrome in a Patient with Gastrointestinal Stromal Tumor

Tumor Lysis syndrome (TLS) is a well-known oncological emergency. It is most commonly associated with bulky and highly proliferative tumors such as leukemias and lymphomas where destruction of cells, usually from chemotherapy, leads to hyperuricemia, hyperkalemia, hyperphosphatemia and hypocalcemia. Such metabolic derangements can lead to renal failure and potentially fatal cardiac arrhythmias. New biologically directed therapies such as imatinib mesylate, a selective tyrosine kinase inhibitor against the proto-oncogene c-kit, may make TLS more common. We present a case of a patient with progressive metastatic gastrointestinal stromal tumor who, during treatment with imatinib mesylate, developed severe TLS ultimately leading to death. This case outlines the importance of clinicians to ensure appropriate monitoring of patient’s metabolic status during treatment with cytotoxic chemotherapy and biologically directed therapies, including oral agents such as imatinib, and to consider rasburicase or allopurinol and hydration as prophylaxis in high-risk populations.

Giving Oncolytic Vaccinia Virus More BiTE

Two of the most exciting new areas of cancer therapy are the use of oncolytic viruses and immune-stimulating monoclonal antibodies. Each approach has shown great promise in animal models and some successes in early clinical trials, but there remain significant barriers to highly effective therapy. To date, the two technologies have been developed independently of each other, for the most part. However, in this issue of Molecular Therapy, Yu et al.1 describe experiments that combine the strengths of both approaches by creating an oncolytic vaccinia virus (VV) that has the ability to home to tumors where it can replicate and induce tumor lysis but also has the ability to secrete a bispecific T-cell engager (BiTE) that can bind T cells to tumor cells and additionally induce immune-mediated tumor cell destruction (Figure 1).

Bortezomib Induced Tumor Lysis Syndrome in Multiple Myeloma

The tumor lysis syndrome (TLS) commonly occurs in the lymphoproliferative disorder, either spontaneously or in response to therapy. TLS is uncommon in multiple myeloma. However, with the use of bortezomib in the treatment of multiple myeloma, cases of TLS have been reported. We report here threepatients who presented with TLS after the administration of bortezomib. Two of them presented mild symptoms and recovered with hydration only. However, death of the other patient was associated with TLS. We should monitor patients who had high tumor burden, especially in early phase of bortezomib therapy and appropriate prophylaxis for high risk patient is also needed.

Trastuzumab Mediated T-Cell Response against HER-2/Neu Overexpressing Esophageal Adenocarcinoma Depends on Intact Antigen Processing Machinery

BackgroundEsophageal adenocarcinoma (EAC) is a highly aggressive disease with poor prognosis, which frequently exhibits HER-2 gene amplification. Trastuzumab, the humanized antibody against HER-2, has potent growth inhibitory effects on HER-2 overexpressing cancers. One effect of trastuzumab is that it causes HER-2 receptor internalization and degradation, enhancing presentation of HER-2 epitopes on MHC-Class I molecules. This enhances the ability of HER-2 specific cytotoxic T lymphocytes (CTLs) to recognize and kill cancer cells. Novel strategies targeting the HER-2 receptor either directly by trastuzumab and/or indirectly by inducing a CTL response against HER-2 epitopes with, for instance, DC immunotherapy and consequently combining these strategies might prove to be very effective.Methodology/Principal FindingsIn this study we report that trastuzumab has potent growth inhibitory effects on two HER-2 overexpressing EAC cell lines OE33 and OE19. However, we found that trastuzumab and HER-2 specific CTLs act synergistically in inducing tumor lysis in OE33 but not in OE19. We discovered that in OE19 this deficient response is due to a down-regulation of the Transporter Associated with Antigen Processing-2 (TAP-2). TAP-2 is an important member of the Antigen Processing Machinery (APM), and is one of the essential elements for loading antigens on MHC class I molecules. Importantly, we demonstrated that by inducing re-expression of TAP-2 in OE19 with INF-γ treatment or by incubating the cells with INF-γ producing CTLs, the specific anti HER-2 CTL tumor lysis response and synergistic effect with trastuzumab can be restored.ConclusionAn inefficient response of HER-2 overexpressing EAC to trastuzumab and/or DC immunotherapy can be due to a down-regulated TAP-2 expression and thus a deficient APM. Future studies combining trastuzumab with IFN-γ and/or immune-therapies inducing potent anti HER-2 CTL responses could lead to an effective combinatorial strategy for successful treatment of HER-2 overexpressing but APM defective cancers.

Sunitinib inducing tumor lysis syndrome in a patient treated for renal carcinoma

Sunitinib is an oral antityrosine kinase inhibitor that has antiangiogenic and antitumor activities. It has been approved for the treatment of advanced RCC and for imatinib-refractory gastrointestinal stromal tumors (GIST). Tumor lysis syndrom can occur in solid tumors. We report a case of patient with metastatic RCC treated with sunitinib with a diagnosis of tumor lysis syndrome.

Phase II Clinical Trial of Flavopiridol (FL) Followed by ara-c and Mitoxantrone (AM) for Adults with Relapsed and Refractory Acute Leukemias.

The cell cycle inhibitor FL targets cyclin-dependent kinases, induces checkpoint arrest and interrupts transcriptional elongation. We demonstrated in an in vitro model that F causes apoptosis in leukemic blasts and increases A cytotoxicity in remaining blasts (Clin Cancer Res 9: 307–315, 2003). Based on these observations, we have conducted a Phase II trial of timed sequential therapy (TST) with FL 50 mg/m2 daily x 3 days followed by A 2 gm/m2/72 hr infusion beginning day 6 and M 40 mg/m2 day 9 (FLAM). A total of 42 adults (median age 50, range 23–75) received FLAM for acute myelogenous leukemia (AML, 37 pts) or acute lymphoblastic leukemia (ALL, 5 pts). Four pts had new AML (myelodysplasia- or treatment-related), 19 were in relapse after first complete remission (CR; median duration 8 mos, range 1.5 – 20), and 19 had refractory leukemia (9 primary). Four pts had prior allo- or auto-stem cell transplants, 13 (31%) had secondary AML and 25 (60%) had adverse cytogenetics, including 2 with Ph+ ALL. FLAM was well-tolerated with death occurring in only 3/42 (7%, fungemia, respiratory distress, multi-organ failure). Grade ≥ 3 non-hematologic toxicities consisted of oral mucositis (2/42, 5%), diarrhea (1/42, 2%), cardiac arrhythmia or decreased ejection fraction (3/42, 7%). F induced tumor lysis in 14 (33%) within 24 hrs of first F dose and a ≥ 50% fall in WBC after 2 F doses in 18 (43%). Median time to neutrophils ≥ 500/mm3 was day 30 day (range 24–46) and platelets ≥50,000/mm3 was day 35 (range 24 – 55). CR was achieved after 1 course of FLAM in 15/37 (41%) AML: 3/4 new patients (including complex cytogenetics), 11/19 relapse and 1/9 primary refractory. CR was achieved in 1/5 (20%) ALL in a patient with relapsed Ph+ ALL. Two of 4 with prior transplant achieved CR, while no patient who was refractory to multiple chemotherapies achieved CR. Of the 15 achieving CR, 13 received additional therapy. Eight pts (7 CR, 1 partial response; median age 45, range 26–62; 1 new diagnosis, 6 relapse, 1 primary refractory) went on to receive allo-transplant in second CR, with CR 2 durations 4.5–12+ mos. An additional 2 pts (ages 45, 46) who had relapsed after allo-transplant in CR1 were able to receive donor lymphocyte infusions (DLI) after FLAM and remain in CR2 of 8+ mos duration. Three pts over age 65 received a second cycle of FLAM in CR, with CR durations of 8.5+, 10, and 10.5 mos. Induction chemotherapy with FLAM yields a significant CR rate in pts with newly diagnosed poor-risk AML or in pts with short CR1, and allows eligible pts to proceed to allo-transplant in CR2.

Primary Malignant Lymphoma of the Duodenum in a Patient with AIDS

Introduction: Biliary tract obstruction in patients with AIDS is most often related to infectious or idiopathic AIDS cholangiopathy. Extensive review of the literature reveals only one report of primary Non Hodgkins Lymphoma (NHL) of duodenum manifesting as obstructive jaundice. Case Report: A 49-year-old homosexual white male was admitted to the hospital for jaundice and right-sided abdominal pain. He also had pruritus, early satiety and 20 lb weight loss. Physical examination revealed jaundice, but there was no peripheral lymphadenopathy or hepatosplenomegaly. Bilirubin was 6.4 mg/dl, AST 341 IU/L, ALT 561 IU/L, alkaline phosphatase 913 IU/L. LDH, amylase, lipase, WBC, hemoglobin were normal. CD4 count was 267 /μL. Ultrasound of the biliary tree visualized dilation of the common bile duct and pancreatic duct. Abdominal CT scan demonstrated common bile duct dilation and circumferential thickening of the third part of the duodenum. EGD revealed a mass in the second part of the duodenum, which was biopsied. Pathology demonstrated malignant large cell lymphoma. Bone marrow biopsy revealed marrow involvement with lymphoma. He received chemotherapy with Rituximab, Cyclophosphamide, Doxorubicin and Prednisone and went into remission. Discussion: The most common biliary cause of jaundice in AIDS is AIDS cholangiopathy which is usually seen in patients with a CD4 count below 100/mm3. NHL is an infrequent cause of jaundice. NHL is primarily encountered in patients with more advanced HIV infection (CD4 below 100/μL). The gastrointestinal tract is one of the most frequent extranodal sites of presentation. The major presenting features of these tumors are pain and weight loss; life-threatening complications such as bleeding, perforation and obstruction occur in about 40% of these patients. Patients with gastrointestinal tract lymphoma may be more likely to respond to aggressive therapy and survive longer than those with the predominant bulk of the tumor in other organs. Chemotherapy induced tumor lysis can be associated with perforation in large transmural lesions. Fortunately, our patient did not experience perforation despite the large size of the primary tumor. However our report does highlight the importance of considering periampullary lymphoma as an opportunistic cause of biliary obstruction in patients with AIDS and also highlights the importance of prompt diagnosis and aggressive treatment as it improves quality of life and survival given the good response to chemotherapy.

Purification of Dolabellanin-C an antineoplastic glycoprotein in the body fluid of a sea hare, Dolabella auricularia

An antineoplastic factor, dolabellanin C, inducing tumor lysis was purified to apparent homogeneity from the body fluid of the sea hare Dollabella auricularia. Purified dolabellanin C is a glyco-protein of 215 K daltons containing 3 subunits of 70 K daltons. The amino acid sequence of the amino terminal region was also determined. This factor was active even at 0.38 ng protein/ml, but did not lyse normal white or red blood cells.

Biopolymers from marine invertebrates. XI. Characterization of an antineoplastic glycoprotein, dolabellanin A, from the albumen gland of a sea hare, Dolabella auricularia.

An anti-neoplastic factor, dolabellanin A, inducing tumor lysis was purified from the albumen gland of a sea hare, Dolabella auricularia. Purified dolabellanin A was found to be a glycoprotein of 250 kilodaltons containing 4 subunits. This factor was half-maximally active towards a variety of tumor cells at 1-18 ng protein/ml and lysed tumor necrosis factor (TNF)-resistant tumor cells. Dolabellanin A was labile on heating, at low and high pH, and on treatment with urea, guanidine, sodium lauryl sulfate or trypsin, but not with 2-mercaptoethanol or periodate. Dolabellanin A completely inhibited the syntheses of deoxyribonucleic acid and ribonucleic acid by tumor cells within 1 h and caused their complete cytolysis within 18 h. Tumor lysis by dolabellanin A was not inhibited by anti-TNF antibody but was inhibited by certain sugars, suggesting that recognition of a sugar moiety is a key step in its induction of cytolysis. Dolabellanin A also prolonged the survival of mice bearing syngeneic MM46 ascitic tumors (p less than 0.001). These results suggest that dolabellanin A, found in an invertebrate, the sea hare, is a new antitumor factor.

Respiratory tract fistulae in recurrent aerodigestive cancers after chemotherapy.

Bronchoesophageal fistulae, a form of respiratory tract fistula, occurred in four patients with squamous cell carcinoma arising in the esophagus or left bronchus after cytoreductive chemotherapy. All four had locoregional cancer, recurrent after high-dose external radiation therapy. Esophageal cancer was treated with sequential intravenous cisplatin 100 mg/m2 (day 1) and 5-fluorouracil (5-FU) 40 mg/m2/hour X 120 (days 2-7). Lung cancer was treated with sequential intravenous cisplatin 100 mg/m2 (day 1), 5-FU 40 mg/m2/hour X 72 (days 2-5), and etoposide 80 mg/m2/day X 3 (days 2, 3, and 4). All patients had symptomatic relief and tumor regression after oncolytic chemotherapy, which was well tolerated with no hematologic toxicity. After the second or third cycle of chemotherapy, bronchoesophageal fistula occurred in all four patients with manifestations of pneumonia, which proved fatal in two patients. The other two patients were effectively palliated for 14 and 36+ weeks after celestin tube placement. Bronchoesophageal fistula should be managed by antibiotics and respiratory support followed by elective placement of celestin tube in most patients and by esophageal exclusion or esophageal bypass in a few select patients. In aerodigestive cancers, respiratory tract fistula may be a rare and potentially fatal complication of chemotherapy induced tumor lysis.