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PURPOSE Small-cell lung cancer (SCLC) is an aggressive malignancy with limited treatments. Delta-like ligand 3 (DLL3) is aberrantly expressed in most SCLC. Tarlatamab (AMG 757), a bispecific T-cell engager molecule, binds both DLL3 and CD3 leading to T-cellb–mediated tumor lysis. Herein, we report phase I results of tarlatamab in patients with SCLC. PATIENTS AND METHODS This study evaluated tarlatamab in patients with relapsed/refractory SCLC. The primary end point was safety. Secondary end points included antitumor activity by modified RECIST 1.1, overall survival, and pharmacokinetics. RESULTS By July 19, 2022, 107 patients received tarlatamab in dose exploration (0.003 to 100 mg; n = 73) and expansion (100 mg; n = 34) cohorts. Median prior lines of anticancer therapy were 2 (range, 1-6); 49.5% received antiprogrammed death-1/programmed death ligand-1 therapy. Any-grade treatment-related adverse events occurred in 97 patients (90.7%) and grade b % 3 in 33 patients (30.8%). One patient (1%) had grade 5 pneumonitis. Cytokine release syndrome was the most common treatment-related adverse event, occurring in 56 patients (52%) including grade 3 in one patient (1%). Maximum tolerated dose was not reached. Objective response rate was 23.4% (95% CI, 15.7 to 32.5) including two complete and 23 partial responses. The median duration of response was 12.3 months (95% CI, 6.6 to 14.9). The disease control rate was 51.4% (95% CI, 41.5 to 61.2). The median progression-free survival and overall survival were 3.7 months (95% CI, 2.1 to 5.4) and 13.2 months (95% CI, 10.5 to not reached), respectively. Exploratory analysis suggests that selecting for increased DLL3 expression can result in increased clinical benefit. CONCLUSION In patients with heavily pretreated SCLC, tarlatamab demonstrated manageable safety with encouraging response durability. Further evaluation of this promising molecule is ongoing.

The Supplementary Material includes the full inclusion and exclusion criteria and additional methods for the skin punch biopsy. Supplementary Table 1 lists AMG 820 pharmacokinetic parameters, Figure S1 shows AMG 820 trough concentrations, Figure S2 shows AMG 820 and CSF1 concentration profiles, Figure S3 shows time-profile plots for IL-34 and TRAP5b, and Figure S4 shows skin punch biopsy images with staining for CD68 and CD115.

Purpose: Binding of colony-stimulating factor 1 (CSF1) ligand to the CSF1 receptor (CSF1R) regulates survival of tumor-associated macrophages, which generally promote an immunosuppressive tumor microenvironment. AMG 820 is an investigational, fully human CSF1R antibody that inhibits binding of the ligands CSF1 and IL34 and subsequent ligand-mediated receptor activation. This first-in-human phase I study evaluated the safety, pharmacokinetics, pharmacodynamics, and antitumor activity of AMG 820.Experimental Design: Adult patients with relapsed or refractory advanced solid tumors received intravenous AMG 820 0.5 mg/kg once weekly or 1.5 to 20 mg/kg every 2 weeks until disease progression, adverse event (AE), or consent withdrawal.Results: Twenty-five patients received ≥1 dose of AMG 820. AMG 820 was tolerated up to 20 mg/kg; the MTD was not reached. One dose-limiting toxicity was observed (20 mg/kg; nonreversible grade 3 deafness). Most patients (76%) had treatment-related AEs; the most common were periorbital edema (44%), increased aspartate aminotransferase (AST; 28%), fatigue (24%), nausea (16%), increased blood alkaline phosphatase (12%), and blurred vision (12%). No patients had serious or fatal treatment-related AEs; 28% had grade ≥3 treatment-related AEs. Grade 3 AST elevations resolved when treatment was withheld. AMG 820 showed linear pharmacokinetics, with minimal accumulation (Conclusions: AMG 820 was tolerated with manageable toxicities up to 20 mg/kg every 2 weeks. Pharmacodynamic response was demonstrated, and limited antitumor activity was observed. Clin Cancer Res; 23(19); 5703–10. ©2017 AACR.

BackgroundTo determine the safety and efficacy of the anti-colony-stimulating factor 1 receptor (anti-CSF1R) monoclonal antibody AMG 820 in combination with pembrolizumab in patients with select solid tumors.Patients and methodsPatients had advanced, refractory mismatch repair-proficient colorectal cancer, pancreatic cancer, or non-small cell lung cancer (NSCLC) with low (ResultsOverall, 116 patients received ≥1 dose of AMG 820 plus pembrolizumab (18 at 1400 mg AMG 820; 98 at 1100 mg AMG 820). Most patients (64%) were male; the median age was 64 (range 30–86) years. Seven patients had DLTs (1 at 1400 mg AMG 820; 6 at 1100 mg AMG 820). Almost all patients (99.1%) had AEs, 87.9% with grade ≥3 AEs. The most common AEs were increased aspartate aminotransferase (59.5%), fatigue (48.3%), periorbital/face edema (48.3%), and rash/maculopapular rash (37.1%). The best response was immune-related partial response in 3 patients (3%; duration of response 9.2, 10.0, 12.5 months) and immune-related stable disease in 39 patients (34%). None of the completed phase II cohorts met the predefined threshold for efficacy. Post-treatment there was accumulation of serum colony-stimulating factor 1 (CSF1) and interleukin-34, reduction in CSF1-dependent CD16-expressing monocytes, and increased PD-L1 expression and CD4 and CD8 cell numbers in tumor biopsies.ConclusionsThe recommended combination dose of 1100 mg AMG 820 plus 200 mg pembrolizumab had an acceptable safety profile. Although pharmacodynamic effects were observed, antitumor activity was insufficient for further evaluation of this combination in selected patient populations.Trial registration numberNCT02713529

BACKGROUND Blinatumomab, a bispecific monoclonal antibody construct that enables CD3-positive T cells to recognize and eliminate CD19-positive acute lymphoblastic leukemia (ALL) blasts, was approved for use in patients with relapsed or refractory B-cell precursor ALL on the basis of single-group trials that showed efficacy and manageable toxic effects. METHODS In this multi-institutional phase 3 trial, we randomly assigned adults with heavily pre-treated B-cell precursor ALL, in a 2: 1 ratio, to receive either blinatumomab or standardof- care chemotherapy. The primary end point was overall survival. RESULTS Of the 405 patients who were randomly assigned to receive blinatumomab (271 patients) or chemotherapy (134 patients), 376 patients received at least one dose. Overall survival was significantly longer in the blinatumomab group than in the chemotherapy group. The median overall survival was 7.7 months in the blinatumomab group and 4.0 months in the chemotherapy group (hazard ratio for death with blinatumomab vs. chemotherapy, 0.71; 95% confidence interval [CI], 0.55 to 0.93; P = 0.01). Remission rates within 12 weeks after treatment initiation were significantly higher in the blinatumomab group than in the chemotherapy group, both with respect to complete remission with full hematologic recovery (34% vs. 16%, P

Recent advances in antibody technology to harness T cells for cancer immunotherapy, particularly in the difficult-to-treat setting of relapsed/refractory acute lymphoblastic leukemia (r/r ALL), have led to innovative methods for directing cytotoxic T cells to specific surface antigens on cancer cells. One approach involves administration of soluble bispecific (or dual-affinity) antibody-based constructs that temporarily bridge T cells and cancer cells. Another approach infuses ex vivo-engineered T cells that express a surface plasma membrane-inserted antibody construct called a chimeric antigen receptor (CAR). Both bispecific antibodies and CARs circumvent natural target cell recognition by creating a physical connection between cytotoxic T cells and target cancer cells to activate a cytolysis signaling pathway; this connection allows essentially all cytotoxic T cells in a patient to be engaged because typical tumor cell resistance mechanisms (such as T-cell receptor specificity, antigen processing and presentation, and major histocompatibility complex context) are bypassed. Both the bispecific T-cell engager (BiTE) antibody construct blinatumomab and CD19-CARs are immunotherapies that have yielded encouraging remission rates in CD19-positive r/r ALL, suggesting that they might serve as definitive treatments or bridging therapies to allogeneic hematopoietic cell transplantation. With the introduction of these immunotherapies, new challenges arise related to unique toxicities and distinctive pathways of resistance. An increasing body of knowledge is being accumulated on how to predict, prevent, and manage such toxicities, which will help to better stratify patient risk and tailor treatments to minimize severe adverse events. A deeper understanding of the precise mechanisms of action and immune resistance, interaction with other novel agents in potential combinations, and optimization in the manufacturing process will help to advance immunotherapy outcomes in the r/r ALL setting.

Minimal residual disease (MRD), where leukemic cell levels are lower than the morphologic detection threshold, is the most important prognostic factor for acute lymphoblastic leukemia (ALL) relapse during first-line chemotherapy treatment and is standard of care in treatment monitoring and decision making. Limited data are available on the prognostic value of MRD response after relapse. We evaluated the relationship between MRD response and outcomes in blinatumomab-treated adults with relapsed/refractory (R/R) B-cell precursor ALL. Of 90 patients with complete remission (CR) or CR with partial hematologic recovery (CRh), 64 (71.1%) achieved a complete MRD response (no detectable individual rearrangements of immunoglobulin/T-cell receptor genes by polymerase chain reaction [PCR] at a minimum sensitivity level of 10(−4)). Eleven patients had MRD

Various approaches of T-cell-based cancer immunotherapy are currently under investigation, among these are BiTE® (bispecific T-cell engager) antibody constructs, which have a unique design and mechanism of action. They are constructed by genetically linking onto a single polypeptide chain the minimal binding domains of monoclonal antibodies for tumor-associated surface antigens and for the T-cell receptor-associated molecule CD3. Concurrent engagement of the target cell antigen and CD3 leads to activation of polyclonal cytotoxic T-cells, resulting in target cell lysis. Blinatumomab, a BiTE targeting CD19, is being investigated in a broad range of B-cell malignancies and has recently been approved in the USA by the US FDA for Philadelphia chromosome-negative relapsed/refractory B-acute lymphoblastic leukemia under the trade name BLINCYTO™. The BiTE platform is one of the clinically most advanced T-cell immunotherapy options.

Summary Background Adults with relapsed or refractory B-precursor acute lymphoblastic leukaemia have an unfavourable prognosis. Blinatumomab is a bispecific T-cell engager antibody construct targeting CD19, an antigen consistently expressed on B-lineage acute lymphoblastic leukaemia cells. We aimed to confirm the activity and safety profile of blinatumomab for acute lymphoblastic leukaemia. Methods In a multicentre, single-arm, open-label phase 2 study, we enrolled adult patients with Philadelphia-chromosome-negative, primary refractory or relapsed (first relapse within 12 months of first remission, relapse within 12 months after allogeneic haemopoietic stem-cell transplantation [HSCT], or no response to or relapse after first salvage therapy or beyond) leukaemia. Patients received blinatumomab (9 μg/day for the first 7 days and 28 μg/day thereafter) by continuous intravenous infusion over 4 weeks every 6 weeks (up to five cycles), per protocol. The primary endpoint was complete remission (CR) or CR with partial haematological recovery of peripheral blood counts (CRh) within the first two cycles. Analysis was by intention to treat. This trial is registered at ClinicalTrials.gov, number NCT01466179. Findings Between Jan 13, 2012, and Oct 10, 2013, 189 patients were enrolled and treated with blinatumomab. After two cycles, 81 (43%, 95% CI 36–50) patients had achieved a CR or CRh: 63 (33%) patients had a CR and 18 (10%) patients had a CRh. 32 (40%) of patients who achieved CR/CRh underwent subsequent allogeneic HSCT. The most frequent grade 3 or worse adverse events were febrile neutropenia (48 patients, 25%), neutropenia (30 patients, 16%), and anaemia (27 patients, 14%). Three (2%) patients had grade 3 cytokine release syndrome. Neurologic events of worst grade 3 or 4 occurred in 20 (11%) and four (2%) patients, respectively. Three deaths (due to sepsis, Escherichia coli sepsis, and Candida infection) were thought to be treatment-related by the investigators. Interpretation Single-agent blinatumomab showed antileukaemia activity in adult patients with relapsed or refractory B-precursor acute lymphoblastic leukaemia characterised by negative prognostic factors. Further assessment of blinatumomab treatment earlier in the course of the disease and in combination with other treatment approaches is warranted. Funding Amgen.

Approximately 30-50% of adults with acute lymphoblastic leukemia (ALL) in hematologic complete remission following multiagent therapy exhibit minimal residual disease (MRD) by reverse transcriptase-polymerase chain reaction or flow cytometry. MRD is the strongest predictor of relapse in ALL. In this open-label, single-arm study, adults with B-cell precursor ALL in hematologic complete remission with MRD (≥10-3) received blinatumomab 15 µg/m2/day by continuous intravenous infusion for up to four cycles. Patients could undergo allogeneic hematopoietic stem cell transplantation any time after cycle 1. The primary endpoint was complete MRD response status after one cycle of blinatumomab. One hundred sixteen patients received blinatumomab. Eighty-eight of 113 evaluable patients (78%) achieved a complete MRD response. In the subgroup of 110 patients with Philadelphia-chromosome negative ALL in hematologic remission, the Kaplan-Meier estimate of relapse-free survival (RFS) at 18 months was 53%. Median overall survival was 36.5 months. In a landmark analysis, complete MRD responders had longer relapse-free survival (23.6 vs 5.7 months; P=0.002) and overall survival (OS) (38.9 vs 12.5 months; P=0.002) compared with MRD nonresponders. Adverse events were consistent with previous studies of blinatumomab. Twelve (10%) patients and three (3%) patients had grade 3 or 4 neurologic events, respectively. Four (3%) patients had cytokine release syndrome (two grade 1 and two grade 3), all during cycle 1. Following treatment with blinatumomab in a population of patients with MRD-positive B-cell precursor ALL, the majority achieved a complete MRD response, which was associated with significantly longer RFS and OS compared with MRD nonresponders. The study is registered to https://clinicaltrials.gov as NCT01207388.

Purpose: Binding of colony-stimulating factor 1 (CSF1) ligand to the CSF1 receptor (CSF1R) regulates survival of tumor-associated macrophages, which generally promote an immunosuppressive tumor microenvironment. AMG 820 is an investigational, fully human CSF1R antibody that inhibits binding of the ligands CSF1 and IL34 and subsequent ligand-mediated receptor activation. This first-in-human phase I study evaluated the safety, pharmacokinetics, pharmacodynamics, and antitumor activity of AMG 820. Experimental Design: Adult patients with relapsed or refractory advanced solid tumors received intravenous AMG 820 0.5 mg/kg once weekly or 1.5 to 20 mg/kg every 2 weeks until disease progression, adverse event (AE), or consent withdrawal. Results: Twenty-five patients received ≥1 dose of AMG 820. AMG 820 was tolerated up to 20 mg/kg; the MTD was not reached. One dose-limiting toxicity was observed (20 mg/kg; nonreversible grade 3 deafness). Most patients (76%) had treatment-related AEs; the most common were periorbital edema (44%), increased aspartate aminotransferase (AST; 28%), fatigue (24%), nausea (16%), increased blood alkaline phosphatase (12%), and blurred vision (12%). No patients had serious or fatal treatment-related AEs; 28% had grade ≥3 treatment-related AEs. Grade 3 AST elevations resolved when treatment was withheld. AMG 820 showed linear pharmacokinetics, with minimal accumulation ( Conclusions: AMG 820 was tolerated with manageable toxicities up to 20 mg/kg every 2 weeks. Pharmacodynamic response was demonstrated, and limited antitumor activity was observed. Clin Cancer Res; 23(19); 5703–10. ©2017 AACR.

Multi-agent chemotherapy is the standard treatment for most B cell malignancies. Since chemotherapy can be associated with significant toxicity and since relapses resistant to chemotherapy often develop, new therapies are needed. Blinatumomab (AMG 103 or MT103) is a late-stage candidate in clinical development, which belongs to a novel class of antibody constructs termed bi-specific T cell engager antibodies. This antibody construct has dual specificity for CD19 and CD3 and can re-direct polyclonal cytotoxic T lymphocytes toward the tumor. This review focuses on the pre-clinical and clinical development of blinatumomab as a powerful new tool in the treatment of B cell malignancies.

For decades, chemotherapy has been the backbone for the treatment of patients with B cell malignancies. Depending on the individual disease, monoclonal antibodies, irradiation and/or hematopoietic stem cell transplantation are added. However, the current standard of care--particularly for patients with relapsed disease--is often not sufficient to achieve durable remissions. A highly promising new drug candidate in late-stage clinical development for treatment of B cell malignancies is blinatumomab (MT103 or AMG 103). This bispecific antibody construct has dual specificity for CD19 and CD3 and belongs to the class of bispecific T cell engager (BiTE®) antibodies, which can potentially engage all cytotoxic T cells of a patient for redirected lysis of tumor cells. Here, we review how blinatumomab has so far been pre-clinically and clinically developed for the treatment of patients with non-Hodgkin's lymphoma and acute lymphoblastic leukemia.

Purpose Blinatumomab is a CD19/CD3 BiTE (bispecific T-cell engager) antibody construct for the treatment of Philadelphia chromosome–negative acute B-lymphoblastic leukemia. We evaluated blinatumomab in relapsed/refractory B-cell non-Hodgkin lymphoma (NHL). Patients and Methods This 3 + 3 design, phase I dose-escalation study determined adverse events and the maximum tolerated dose (MTD) of continuous intravenous infusion blinatumomab in patients with relapsed/refractory NHL. Blinatumomab was administered over 4 or 8 weeks at seven different dose levels (0.5 to 90 μg/m2/day). End points were incidence of adverse events, pharmacokinetics, pharmacodynamics, and overall response rate. Results Between 2004 and 2011, 76 heavily pretreated patients with relapsed/refractory NHL, who included 14 with diffuse large B-cell lymphoma, were enrolled; 42 received treatment in the formal dose-escalation phase. Neurologic events were dose limiting, and 60 μg/m2/day was established as the MTD. Thirty-four additional patients were recruited to evaluate antilymphoma activity and strategies for mitigating neurologic events at a prespecified MTD. Stepwise dosing (5 to 60 μg/m2/day) plus pentosan polysulfate SP54 (n = 3) resulted in no treatment discontinuations; single-step (n = 5) and double-step (n = 24) dosing entailed two and seven treatment discontinuations due to neurologic events, respectively. Grade 3 neurologic events occurred in 22% of patients (no grade 4/5). Among patients treated at 60 μg/m2/day (target dose; n = 35), the overall response rate was 69% across NHL subtypes and 55% for diffuse large B-cell lymphoma (n = 11); median response duration was 404 days (95% CI, 207 to 1,129 days). Conclusion In this phase I study of relapsed/refractory NHL, continuous infusion with CD19-targeted immunotherapy blinatumomab at various doses and schedules was feasible, with an MTD of 60 μg/m2/day. Single-agent blinatumomab showed antilymphoma activity.

T cell–engaging CD19/CD3-bispecific BiTE Ab blinatumomab has shown an 80% complete molecular response rate and prolonged leukemia-free survival in patients with minimal residual B-lineage acute lymphoblastic leukemia (MRD+ B-ALL). Here, we report that lymphocytes in all patients of a phase 2 study responded to continuous infusion of blinatumomab in a strikingly similar fashion. After start of infusion, B-cell counts dropped to < 1 B cell/μL within an average of 2 days and remained essentially undetectable for the entire treatment period. By contrast, T-cell counts in all patients declined to a nadir within < 1 day and recovered to baseline within a few days. T cells then expanded and on average more than doubled over baseline within 2-3 weeks under continued infusion of blinatumomab. A significant percentage of reappearing CD8+ and CD4+ T cells newly expressed activation marker CD69. Shortly after start of infusion, a transient release of cytokines dominated by IL-10, IL-6, and IFN-γ was observed, which no longer occurred on start of a second treatment cycle. The response of lymphocytes in leukemic patients to continuous infusion of blinatumomab helps to better understand the mode of action of this and other globally T cell–engaging Abs. The trial is registered with www.clinicaltrials.gov identifier NCT00560794.

Regulatory (FOXP3+) T cells (Tregs) comprise a subpopulation of CD4+ T cells that suppress autoreactive immune cells, thereby protecting organs and tissues from autoimmunity. Tregs have also been detected in human malignancies and their depletion or inactivation substantially improves cellular antitumor immunity in preclinical studies. Novel therapeutic strategies for cervical cancer and precancerous cervical intraepithelial neoplasia (CIN) focus on immune-modulatory and cancer vaccination approaches. In this context, the frequency of Tregs in cervical cancer and precancerous CIN could influence therapeutic strategies. We determined the frequency of infiltrating CD4+ and CD8+ T cells as well as FOXP3+ Tregs in high-grade CIN lesions (CIN III) and cervical carcinoma compared to colon carcinoma, skin melanoma, and bronchial carcinoma. We show that human papilloma virus-derived lesions have a significantly higher number of infiltrating lymphocytes and FOXP3+ Tregs compared to three other common tumor entities. In addition we explored the therapeutic effect of agonistic anti-glucocorticoid-induced tumor necrosis factor receptor family-related protein antibodies that, by single systemic application, inactivate Tregs and induce strong intratumoral invasion of CD8+ T cells and complete tumor eradication in 70% of treated animals. The large number of Tregs in human papilloma virus-derived lesions suggests a pivotal role of Tregs for counteracting the host immune response. We therefore regard CIN and cervical cancer as prime targets for new immune-based non-invasive therapies.

Hematologic malignancies are predominantly treated with chemotherapy or a combination of chemotherapy with monoclonal antibodies. Current treatment regimens often are not satisfactory due to severe side effects and a substantial proportion of relapsed patients. This has prompted the development of better tolerated and more efficacious immunotherapeutic strategies for the treatment of lymphoma and leukemia. With blinatumomab (MT103) a first antibody, which can potentially engage all cytotoxic T cells of a patient for tumor cell lysis, is now available for clinical evaluation. Blinatumomab is a single-chain bispecific antibody construct with specificity for CD19 and CD3 belonging to the class of bispecific T cell engager. Here, we review the current progress in development of blinatumomab for treatment of patients with CD19-expressing hematological malignancies.

Persistent polyclonal B-cell lymphocytosis (PPBL) is an extremely rare disorder, which occurs almost exclusively in smoking women and is characterized by a lymphocytosis with circulating binucleated lymphocytes. We analyzed 25 PPBL patients with respect to immunophenotype and by adaptive cluster analysis system (ACAS). Furthermore, HLA type, presence of Epstein-Barr virus (EBV) DNA in B cells, and clinical data were evaluated. Overall, the median percentages of B cells in PPBL patients with expression of CD5(dim), CD23(dim), CD25, CD27, and FMC7 were 21%, 38%, 16%, 74%, and 93%. Compared to normal controls, ACAS revealed a subset of nucleic-acid-rich lymphocytes located between the regular lymphocyte and regular monocyte region. Sixteen (64%) of 25 patients carried a HLA DR7 phenotype. Quantitative real-time polymerase chain reaction analysis did not detect relevant amounts of EBV DNA in circulating B cells of any patient. During a median follow-up of 5 years, a single patient developed lymphoplasmacytic lymphoma. The abnormal morphology and frequent, albeit dim, expression of CD5 and CD23 in PPBL may result in erratic diagnostic assignment of this benign disorder. However, incorporation of immunophenotyping and ACAS into the diagnostic algorithm allows recognition of PPBL in routine analysis and its differentiation from malignant B cell lymphoproliferative diseases. We found that an infection of a significant percentage of PPBL cells by EBV is unlikely. The observation of malignant lymphoma in a single patient implicates that evolution into a clonal malignant transformation may occasionally occur in PPBL.

Most cancer vaccination trials have been performed in human leukocyte antigen (HLA)-A2 positive populations. Some studies have used HLA-A2 negative patients as control group. However, HLA-type and HLA-expression can interact with tumor biology and possibly affect prognosis. HLA-A2 negative patients might constitute an inadequate control group.Patients with colorectal cancer were serologically analyzed for HLA-A2 expression. Patients were evaluated for tumor stage, grading, tumor location. Overall survival (OAS) of HLA-A2 positive and HLA-A2 negative patients was compared.One hundred forty-four patients were evaluable (50% HLA-A2+). Median age was 62 years. UICC stage III or IV: 45.8%. Gender, location, and UICC stage were equally distributed between HLA-A2 subgroups. HLA-A2 positive patients more frequently had grade 3 histology (27.8% vs 13.9%) and chemotherapy (62.9% vs 45.6%). At a median follow-up of 75.8 months, median OAS for the entire study population was 123.3 months, 5-year OAS was 77.5%. No statistically significant difference in OAS was observed between HLA-A2 positive and negative patients (116.5 vs 157 months, 5-year-OAS 74.1+/-11.6% vs 81+/-11.6%, p=0.46). Expectedly, patients with UICC stage I and II disease lived significantly longer than patients with stage III and IV (5-year OAS 94.3% vs 53.4%; p0.001). A significantly superior OAS was also found for women, independent of stage or HLA status.HLA-A2 positive patients exhibit poorer tumor differentiation. This might account for a non-significant difference in OAS. The use of HLA-A2 negative patients as control cohort in CRC vaccinations would rather underestimate potential treatment-related survival effects. Therefore, we suggest they constitute a valid auxiliary control group.

Immunological treatment of cancer has made some very promising advances during the last years. Anti-cancer vaccination using peptides or peptide-pulsed dendritic cells and adoptive transfer of in vitro generated, epitope-specific T cells depend on a well-fitting interaction of HLA molecule and epitope. Accurate HLA-typing is a key factor for successful anti-cancer vaccination. No comprehensive data and no suggestion exist on the HLA-typing in this setting. We performed a systematic review of PubMed analyzing HLA-typing data in cancer vaccination trials over the last 4 years (2004-2007). Then, using the SYFPEITHI database, we calculated the peptide binding prediction of the eight most often used HLA-A*0201 binding epitopes. Finally, high-resolution typing [by sequence-specific primers (SSP)] data of a HLA-A*02 or HLA-A*24 positive population in Berlin, Germany, were analyzed. Forty-five cancer vaccination trials with 764 patients were included. Eighteen studies were performed in the USA, 13 in Europe, 12 in Asia (mainly Japan), and two in Australia. Most common diseases targeted were melanoma, prostate cancer, colorectal cancer, renal cell cancer, and breast cancer. The trials tested protocols using peptide plus adjuvants without DC or protocols using peptide-pulsed DC. In 38 trials (84%) HLA-A2 positive patients were vaccinated, in 11 studies (24%) HLA-A24 positive patients were vaccinated. Nineteen studies with 291 patients (38%) presented the HLA type as four-digit code (high-resolution), 26 studies with 473 patients (62%) presented the HLA-type in a low-resolution code. The method of HLA determination was given in six out of 45 trials (13%). Using the SYFPEITHI database we calculated the peptide binding prediction of the eight most often used HLA-A*0201 binding tumor antigen-derived epitopes for binding to HLA-A*0203. While the epitopes had a binding score of 17-28 for HLA-A*0201, the score for binding to HLA-A*0203 was zero in seven out of eight tested peptides. Only for one peptide the score was eight. Finally, we analyzed high-resolution data of HLA-A*02 and HLA-A*24 positive patients in Berlin, Germany. We found the HLA-A*0201 allele and HLA-A*2402 allele in 95%, respectively. HLA-A*0201 and HLA-A*2402 are most commonly used for peptide based vaccine in cancer. Data on HLA-typing given in the included cancer vaccine manuscripts are fractional. Only 13% report the method of HLA typing and most HLA types are given as low-resolution code. Looking at the binding of specific peptides to both the alleles, it is important to perform high-resolution typing. Further suggestions for immunogenetic laboratories and clinical tumor immunologists regarding HLA-typing for cancer vaccine trials and adoptive T cell transfer approaches are discussed.

Few patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL) achieve prolonged disease-free survival. Blinatumomab, a bispecific T-cell engaging antibody construct, transiently links CD3-positive T cells to CD19-positive B cells. This phase 2 study evaluated stepwise (9-28-112 μg/d with weekly dose increases; n = 23) or flat (112 μg/d; n = 2) dosing of blinatumomab by continuous infusion, with dexamethasone prophylaxis, in patients with relapsed/refractory DLBCL. Patients received a median of 3 prior lines of therapy. Median time since last regimen was 1.5 months. Seventeen patients ended treatment in cycle 1 (induction), 7 in cycle 2 (consolidation), and 1 in retreatment. Among 21 evaluable patients, the overall response rate after 1 blinatumomab cycle was 43%, including complete responses (CRs) in 19%. Three patients had late CR in follow-up without other treatment. The most common adverse events with stepwise dosing were tremor (48%), pyrexia (44%), fatigue (26%), and edema (26%). Grade 3 neurologic events with stepwise dosing were encephalopathy and aphasia (each 9%) and tremor, speech disorder, dizziness, somnolence, and disorientation (each 4%). Of 5 (22%) patients who discontinued stepwise dosing because of adverse events, 4 (17%) had neurologic events. Most neurologic events resolved. The flat-dose cohort was stopped because of grade 3 neurologic events in both patients. Blinatumomab monotherapy appears effective in patients with relapsed/refractory DLBCL, a heavily pretreated patient population with a high unmet medical need. Further studies need to define the optimal approach to achieve the target dose without early dropout. The study was registered at www.clinicaltrials.gov as #NCT01741792.

Introduction. MRD in ALL is defined as detection of leukemic cells in bone marrow by polymerase chain reaction (PCR) or flow cytometry with hematologic complete remission (CR). Pts with persistent/recurrent MRD after first-line induction therapy have a higher risk of relapse than those with complete MRD response (no detectable MRD with minimum sensitivity 0.01%). Interventions, including hematopoietic stem cell transplantation (HSCT), are used to improve the outcome of these pts. Blinatumomab, a bispecific T cell engager (BiTE®) antibody construct, redirects CD3+ T cells to CD19+ target cells, resulting in serial lysis of CD19+ B cells. In a multicenter, international phase 2 study in MRD+ ALL (Goekbuget N et al. Blood 2014;124:379), blinatumomab resulted in complete MRD response in cycle 1 in 78% of pts including multiple subgroups such as pts in second-line treatment, those with high MRD burden, and older pts. No subgroups with higher MRD complete response rates were identified. This analysis evaluated long-term outcomes, including overall survival (OS), relapse-free survival (RFS), and duration of remission (DOR). Methods. Adults (≥18 years) with B-cell precursor ALL with hematologic CR ( Results. 116 pts enrolled and received blinatumomab. Median age was 45 years (range 18-76); 15 (13%) pts were age ≥65 years. 90 (78%) pts received HSCT after blinatumomab. 62 (53%) pts were still being followed. 35 pts relapsed and 26 pts died in CR (23 of them after subsequent HSCT). Median OS, with median follow-up of 29.5 mo, was 36.5 mo (95% CI, 19.1 mo to not reached [n.r.]): 40.4 vs 12.0 (P =.001) in pts with (n=88) or without (n=24) MRD complete response in cycle 1. 110 pts were evaluable (CR at study entry, Ph-) for RFS and DOR. Median RFS was 18.9 mo (95% CI, 12.3 to 35.2 mo): 24.6 vs 11.0 (P =0.005) in pts treated in first (n=75) vs later (n=35) remission; and 35.2 vs 7.1 (P =0.002) in pts alive and relapse-free after 45 days with (n=85) or without (n=15) MRD complete response in cycle 1 (Figure). Median DOR was n.r. (95% CI, 24.6 mo to n.r.): n.r. vs 15.0 mo (P =0.002) in pts treated in first vs later remission; and n.r. vs 15.0 mo (P =0.015) in pts with DOR ≥ 45 days with (n=85) or without (n=13) MRD complete response in cycle 1. In time-dependent Cox model analyses, HSCT vs no HSCT were not different for OS (hazard ratio [HR], 1.39; 95% CI, 0.68 to 2.82; P =0.368) or RFS (HR, 0.89; 95% CI, 0.47 to 1.69; P =0.730); DOR (treating death as a competing risk) was longer for HSCT vs no HSCT (HR, 0.36; 95% CI, 0.17 to 0.77; P =0.008). All pts experienced at least one AE. The most clinically relevant were neurologic events, including tremor (30%), aphasia (13%) dizziness (8%), ataxia and paraesthesia (6% each), and encephalopathy (5%). Rates decreased over time (cycles 1, 2, 3, and 4) for any neurologic event (47%, 24%, 15%, and 15%) and any grade ≥3 neurologic event (10%, 4%, 0%, and 0%). 12 (10%) pts interrupted treatment due to grade ≥3 neurologic events: 5 resumed without another interruption and 2 resumed then stopped treatment for another neurologic event. Investigators reported 4 deaths as fatal AEs during follow-up (brain injury, disease progression, gastrointestinal hemorrhage, and multiorgan failure); all 4 pts received HSCT after blinatumomab. Conclusion. In this long-term follow-up analysis of the first large prospective trial with an experimental compound in MRD+ ALL, MRD complete response induced by single-agent blinatumomab treatment was associated with longer OS, RFS, and DOR compared with not achieving an MRD complete response after blinatumomab treatment. This strengthens the current strategy of MRD-based treatment in ALL before occurrence of clinical relapse. Disclosures Gökbuget: Sanofi: Equity Ownership; Pfizer: Consultancy, Honoraria, Research Funding; GlaxoSmithKline: Honoraria, Research Funding; Erytech: Consultancy; Eusapharma/Jazz: Consultancy, Honoraria, Research Funding; Gilead Sciences: Consultancy; Kite: Consultancy; Medac: Consultancy, Honoraria, Research Funding; Mundipharma: Consultancy, Honoraria, Research Funding; Bayer: Equity Ownership; SigmaTau: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria. Off Label Use: Blinatumomab (BLINCYTO®) is approved for the treatment of Philadelphia chromosome-negative relapsed or refractory B-cell precursor acute lymphoblastic leukemia (ALL). It has not been approved for use in patients in hematologic remission, but with presence of minimal residual disease (MRD), from ALL.. Dombret:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Bonifacio:Amgen: Consultancy; Ariad Pharmaceuticals: Consultancy; Pfizer: Consultancy; Novartis Farma: Research Funding. Reichle:University Hospital Regensburg: Employment. Graux:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees. Faul:Amgen: Honoraria. Topp:Astra: Consultancy; Regeneron: Consultancy; Affimed: Consultancy, Research Funding; Roche: Consultancy, Other: Travel Support; Jazz: Consultancy; Pfizer: Consultancy; Amgen: Consultancy, Honoraria, Other: Travel Support. Brüggemann:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Honoraria. Horst:Pfizer: Research Funding; MSD: Research Funding; Gilead: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Boehringer Ingleheim: Research Funding. Stieglmaier:Amgen Research (Munich) GmbH: Employment; Amgen Inc: Equity Ownership. Wessels:Amgen: Employment. Haddad:Amgen Ltd.: Employment; Amgen Inc.: Equity Ownership. Zugmaier:Amgen Res. Munich: Employment. Nagorsen:Amgen: Employment, Equity Ownership, Patents & Royalties: Inventor on blinatumomab-related patent. Bargou:University of Wuerzburg, Germany: Employment; Novartis: Consultancy, Honoraria; GEMoaB GmbH: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Patents & Royalties: Patent for blinatumomab.

Colorectal cancer is a common malignant disease, which, despite some progress, still requires improved therapeutic options. Several clinical studies have used active specific immunotherapy (i.e., vaccination) in colorectal cancer. However, the literature still lacks a comprehensive meta-analysis of this approach in advanced colorectal cancer. We did a systematic review with a meta-analysis of clinical studies to evaluate the objective clinical and immunologic response to active specific immunotherapy in patients with colorectal cancer. We conducted a search of Medline and the Web of Science, manually reviewed the literature, and consulted with experts. Criteria for including studies were colorectal cancer patients, active specific immunotherapy to induce a response directed against cancer or cancer antigens, an evaluable tumor burden (i.e., advanced or metastatic colorectal cancer), and precise classification of the patient, disease, and response. Response rates were assessed according to WHO criteria. Primary end points were the objective clinical response rate and the rate of immunologic responses. The secondary end point was the distribution of immune and clinical responses in relation to the route of vaccination and the type of vaccine. Thirty-two phase I/II studies reporting on 527 patients with advanced or metastatic colorectal cancer met all inclusion criteria. Pooled analysis showed an overall response rate (complete response + partial response) of 0.9% for advanced/metastatic colorectal cancer patients who underwent active specific immunization with a broad variety of substances (e.g., autologous tumor cells, peptide vaccine, dendritic cells, idiotypic antibody, and virus-based vaccine). Humoral immune responses were reported in 59%, and cellular ones were reported in 44% of the cases. Mixed or minor responses and disease stabilization are described in 1.9% and 8.3% of colorectal cancer patients, respectively. Pooled results of clinical trials reveal a very weak clinical response rate of

In a human melanoma model of tumor antigen (TA)–based immunization, we tested the functional status of TA-specific CD8+ cytotoxic T lymphocytes. A “quiescent” phenotype lacking direct ex vivo cytotoxic and proliferative potential was identified that was further characterized by comparing its transcriptional profile to that of TA-specific T cells sensitized in vitro by exposure to the same TA and the T-cell growth factor interleukin 2 (IL-2). Quiescent circulating tumor-specific CD8+ T cells were deficient in expression of genes associated with T-cell activation, proliferation, and effector function. This quiescent status may explain the observed lack of correlation between the presence of circulating immunization-induced lymphocytes and tumor regression. In addition, the activation of TA-specific T cells by in vitro antigen recall and IL-2 suggests that a complete effector phenotype might be reinstated in vivo to fulfill the potential of anticancer vaccine protocols.

The recent progress in tumor immunology is a striking example of the successful application of modern biotechnology to understand the complex phenomenon of immune-mediated cancer rejection. Tumor antigens were identified and successfully utilized in active immunization trials to induce tumor antigen-specific T cells. This achievement has left, however, clinicians and researchers perplexed by the paradoxical observation that immunization-induced T cells can recognize tumor cells in standard assays but cannot induce tumor regression. A closer look at T cell physiology and tumor biology suggests that this observation is not so surprising. Here, we argue that successful immunization is one of several steps required for tumor clearance while more needs to be understood about how T cells localize and are effective within a tumor microenvironment impervious to the execution of their effector function.

Recombinant expression vectors represent a powerful way to deliver whole antigens (Ags) for immunization. Sustained Ag expression in vector-infected dendritic cells (DC) combines Ag-specific stimulation with powerful costimulation and, simultaneously, through 'self-selection' of ad hoc epitopes broadens the scope of immunization beyond restrictions posed by individual patients' human leukocyte antigen (HLA) phenotype. In this study, therefore, we evaluated the efficiency of a recombinant vaccinia virus encoding the gp100/PMel17 melanoma Ag (rVV-gp100) to infect immature (iDC) or mature dendritic cells (mDC) derived from circulating mononuclear cells and the effect of infection on their status of maturation. In addition, we tested the ability of rVV-gp100-infected iDC and mDC to present the HLA-A*0201-associated gp100:209-217 epitope (g209). Irrespective of status of maturation, rVV-gp100 infection induced gp100 expression while only partially reversing the expression of some maturation markers. However, endogenous presentation of the wild-type g209 epitope was inefficient. The low efficiency was epitope-specific since infection of DC with rVV encoding a gp100 construct containing the modified gp100:209-217 (210M) (g209-2M) epitope characterized by high binding affinity for HLA-A*0201 restored efficient Ag presentation. Presentation of an HLA-class II-associated epitope and cytokine release by DC was not altered by rVV infection. Thus, Ag expression driven by rVV may be an efficient strategy for whole Ag delivery. However, since the effectiveness of Ag processing and presentation is subject to stringent HLA/epitope pairing, and for other yet undefined rules, the assumption that whole Ag delivery may circumvent HLA restriction is incorrect and recombinant expression vectors encoding well-characterized polyepitopic constructs may prove more effective.

There is increasing evidence that tumors elicit specific T-cell responses in a substantial proportion of patients. Recently, we have shown that in patients with colorectal cancer specific T cells against the tumor-associated antigens (TAA) Ep-CAM, her-2/neu or CEA can be detected in peripheral blood using IFNγ-ELISPOT assay. In our study, we have analyzed T-cell responses against HLA-A*0201-restricted epitopes of these TAA in peripheral blood of patients with breast cancer and colorectal cancer. Surprisingly, a complete absence of ex vivo T-cell responses against these TAA was found in 20 patients with breast cancer. In contrast, specific T cells were detectable in 12 of 49 patients with colorectal cancer against at least 1 of these TAA, confirming our previous results. T-cell responses against influenza-derived peptides were similar in both malignancies. The results of our study indicate a difference either of tumor immunogenicity or of the migratory pattern of tumor-specific T cells between breast cancer and colorectal cancer patients. The findings reported here have implications for the development of antigen-specific T-cell therapies. © 2003 Wiley-Liss, Inc.

Classification of cytokines as pro- versus anti-inflammatory might not apply to the pleiotropic effects of interleukin-10 (IL-10). Several reports suggest that IL-10 enhances the function of natural killer cells, which leads, through pathogen destruction, to increased antigen availability. In addition, by inhibiting the maturation of antigen-presenting cells (APCs), IL-10 preserves their ability for antigen uptake while simultaneously hampering their migration to draining lymph nodes. This review suggests that this ‘antigen-loading’ phase might constitute an important component of the innate immune reaction to a pathogen. Additional proinflammatory stimuli might subsequently lead to maturation of ‘loaded’ APCs that could migrate to draining lymph nodes or recruit and activate adaptive immune effectors locally.

Antigen-specific CD8-expressing T cells play a crucial role in the host's defense against viral disease and malignancy. Epitope-specific CD8 + T cell responses to malignant and viral disease can be accurately measured using tetramers (tHLA) of HLA class I molecules loaded with antigenic peptides. In addition, tHLA have been used to evaluate immune responses to antigen-specific immunization. tHLA bind specifically to complementary T-cell receptor (TCR) structures on the surface of T cells expressing the CD8 coreceptor. Surprisingly, however, CD8 - cells binding tHLA are often observed. This study uses four-color flow cytometry to show that HLA-A*0201-tHLA-stained CD8 - cells can be divided into two subsets: 87% represent B-lymphocytes (CD19 + , CD45RA + , HLA-DR + , and CD20 + ), and 13% represent T-helper cells (CD3 + , CD4 + , CD45RA + , and CD27 + ). This phenomenon is not HLA-restricted because it could be observed even in peripheral blood mononuclear cells (PBMC) from a non HLA-A*0201-expressing healthy donor. In addition, no T-cell receptor was detected on the B-lymphocytes. Retrospective enumeration of vaccine-induced CD8 - tHLA + cells in 243 PBMC samples from 36 patients with melanoma undergoing peptide vaccination revealed that tHLA staining is not dependent on immunization status or the presence of CD8 + tHLA + T cells. These findings, suggest that the nonspecific binding of tHLA to non-TCR-expressing T cells requires a careful interpretation of results and further steps in preparation of sample for tHLA-based sorting of epitope specific T cells.

Current treatment of chronic lymphocytic leukemia (CLL) patients often results in life-threatening immunosuppression. Furthermore, CLL is still an incurable disease due to the persistence of residual leukemic cells. These patients may therefore benefit from immunotherapy approaches aimed at immunoreconstitution and/or the elimination of residual disease following chemotherapy. For these purposes, we designed a simple GMP-compliant protocol for ex vivo expansion of normal T cells from CLL patients’ peripheral blood for adoptive therapy, using bispecific Ab blinatumomab (CD3 × CD19), acting both as T cell stimulator and CLL depletion agent, and human rIL-2. Starting from only 10 ml CLL peripheral blood, a mean 515 × 106 CD3+ T cells were expanded in 3 wk. The resulting blinatumomab-expanded T cells (BET) were polyclonal CD4+ and CD8+ and mostly effector and central memory cells. The Th1 subset was slightly prevalent over Th2, whereas Th17 and T regulatory cells were

T-cell-based cancer immunotherapies are at the forefront of a new era in cancer treatment. Engaging T cells through BiTE® (bispecific T-cell engager) antibody constructs is one of the most advanced immunotherapeutic approaches. BiTE® antibody constructs have a unique design and mechanism of action. They are constructed by genetically linking the minimal binding domains of monoclonal antibodies for a tumor-associated surface antigen and for the T-cell receptor-associated molecule CD3 onto a single polypeptide chain. Concurrent engagement of the target cell antigen and CD3 leads to activation of polyclonal cytotoxic T-cells, resulting in target cell lysis. The first BiTE®, blinatumomab, targeting CD19 and CD3, is being investigated in a broad range of B-cell malignancies and has recently received an accelerated approval by the US FDA for Philadelphia chromosome-negative relapsed/refractory B-acute lymphoblastic leukemia under the trade name BLINCYTO®. In addition, several BiTE® antibody constructs targeting other tumor antigens have entered the clinical stage of development. Most recent updates about the BiTE® platform will be presented. Citation Format: Dirk Nagorsen. Engaging T cells against cancer: BLINCYTO® and beyond – the BiTE® platform. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr IA14.

Background: T-cell activity is regulated by immune checkpoints to maintain the sensitive balance of co-stimulatory and inhibitory immune signals. Therapeutic blockade of checkpoint molecules on tumor or T cells such as CTLA-4 or PD-L1 has shown clinical success in several tumor types including Hodgkin´s disease. Furthermore, Blinatumomab, a bispecific T-cell engager (BiTE antibody construct) directing cytotoxic T cells to CD19 positive leukemic cells has been approved for treatment of acute lymphoblastic leukemia. The CD33 specific BiTE antibody construct AMG 330 has been developed for the therapy of acute myeloid leukemia (AML) and will be evaluated in phase I studies shortly. In our current study, we investigated the therapeutic utility of blockade of the novel checkpoint proteins PVR (poliovirus receptor) and PVRL2 (poliovirus receptor-related 2) alone and in combination with AMG 330 in AML. Methods and results: Samples from 140 treatment naive patients with newly diagnosed AML (AMLSG 07-04, NCT00151242) were analyzed by RT-qPCR for expression of the immune checkpoint molecules PVR, PVRL2 and Galectin-9 (Gal-9). Expression was correlated with patient demographics (age, karyotype, FLT3 mutation status) and clinical survival data by multivariate cox regression. The majority of patients showed mRNA expression of PVR (94%), PVRL2 (95%) and Gal-9 (92%). In a multivariate stepwise cox regression for overall survival, an unfavorable karyotype, high PVR and high Gal-9 expression were identified as independent prognostic markers (p In a second, independent patient cohort containing microarray-based gene expression and clinical data of 291 AML patients (Verhaak et.al., Haematologica 2009;94) a high PVR and PVRL2 expression in contrast to expression of CD80, CD86 or PD-L1 was associated with poor overall survival (log-rank test p=0.003 and p=0.032, respectively). In in vitro killing assays the therapeutic effect of PVR and PVRL2 blockade was studied by FACS using 7-AAD staining. AML cell lines MV4-11, Kasumi-1 and Molm-13 were preincubated with blocking antibodies against PVR, PVRL2 or both and co-cultured for 24h with peripheral blood mononuclear cells (PBMCs) of healthy donors in the presence or absence of AMG 330. In the absence of AMG 330, the cell kill of MV4-11 increased from 12.6±4.7% (control) to 33.0±8.8% (PVR), to 40.4±10.4% (PVRL2) and to 56.0±12.0% (both PVR + PVRL2). In the presence of suboptimal concentration of AMG 330 (0.1 ng/ml) MV4-11 cell lysis was 29.4±9.0% (AMG 330 alone), 49.7±12.6% (AMG 330 + PVR), 57.9±11.3% (AMG 330 + PVRL2) and 70.0±9.8% (AMG 330 + PVR + PVRL2; n=4, p Conclusion: The expression of immune checkpoint ligands PVR and PVRL2 confers a negative prognosis to AML patients possibly due to immune evasion. We could further show that the killing of AML cells by PBMCs could be augmented by blockade of these novel checkpoint inhibitors. Furthermore, addition of PVR and/or PVRL2 blocking antibodies to AMG 330 could enhance cytotoxicity. Therefore, blockade of PVR and PVRL2 represents a promising target for the treatment of AML. Disclosures Kischel: Amgen Research (Munich) GmbH: Employment. Stienen:Amgen Research (Munich) GmbH: Employment. Friedrich:Amgen Research (Munich) GmbH: Employment. Lutteropp:Amgen Research (Munich) GmbH: Employment. Nagorsen:Amgen: Employment, Equity Ownership, Patents & Royalties: Inventor on blinatumomab-related patent.

Purpose Blinatumomab, a bispecific single-chain antibody targeting the CD19 antigen, is a member of a novel class of antibodies that redirect T cells for selective lysis of tumor cells. In acute lymphoblastic leukemia (ALL), persistence or relapse of minimal residual disease (MRD) after chemotherapy indicates resistance to chemotherapy and results in hematologic relapse. A phase II clinical study was conducted to determine the efficacy of blinatumomab in MRD-positive B-lineage ALL. Patients and Methods Patients with MRD persistence or relapse after induction and consolidation therapy were included. MRD was assessed by quantitative reverse transcriptase polymerase chain reaction for either rearrangements of immunoglobulin or T-cell receptor genes, or specific genetic aberrations. Blinatumomab was administered as a 4-week continuous intravenous infusion at a dose of 15 μg/m2/24 hours. Results Twenty-one patients were treated, of whom 16 patients became MRD negative. One patient was not evaluable due to a grade 3 adverse event leading to treatment discontinuation. Among the 16 responders, 12 patients had been molecularly refractory to previous chemotherapy. Probability for relapse-free survival is 78% at a median follow-up of 405 days. The most frequent grade 3 and 4 adverse event was lymphopenia, which was completely reversible like most other adverse events. Conclusion Blinatumomab is an efficacious and well-tolerated treatment in patients with MRD-positive B-lineage ALL after intensive chemotherapy. T cells engaged by blinatumomab seem capable of eradicating chemotherapy-resistant tumor cells that otherwise cause clinical relapse.

Diastolic heart failure is a rising problem with a high incidence and similar mortality and morbidity compared to patients with systolic heart failure. Nevertheless, the underlying pathophysiology is still debated.We investigated the effect of pharmacological enhancement of endothelial nitric oxide synthase (eNOS) on experimental diastolic heart failure (DHF).DHF was induced in 60 DAHL salt-sensitive rats by salt diet in 8-week-old animals. 30 were treated with the eNOS enhancer AVE3085 (DHFeNOS) and 30 with placebo (DHF). Rats with normal salt intake served as controls.Diastolic dysfunction with increased diastolic stiffness constant and increased left ventricular (LV) pressure was analyzed by invasive pressure-volume loop measurements in the DHF group compared to controls. Cardiac hypertrophy as indicated by LV mass measurements by echocardiography, and increased cardiac collagen content as measured by immunohistochemistry were associated with an increased activation state of calcineurin, AKT, ERK(1/2), but not JNK and p38 kinases. Titin isoforms were not altered in this model of DHF. Treatment with AVE3085 significantly increased eNOS mRNA and protein levels in the cardiac tissue and decreases NAD(P)H oxidase subunits p22phox and gp91phox. Diastolic dysfunction was attenuated and cardiac hypertrophy and fibrosis were improved in comparison with untreated DHF animals. This was associated with a normalized activation state of calcineurin, AKT and ERK(1/2). Therefore, we suggest that targeting the NO system might yield a future therapeutic aim for the treatment of DHF.

Background Quantification of T-cell receptor (TCR) chain families can be utilized for detection of clonal T-cell populations. Besides southern blotting and antibody-based approaches, quantitative real time PCR (qRT PCR) has been more widely applied in this context during the last years. Here, the heterogeneity of sequences within single families is the most challenging problem for exact quantification. Method Vβ-families were quantified using a universal reverse primer and family-specific forward primers with TaqMan technology on a light cycler instrument. Relative concentrations were calculated considering slopes and crossing points of each PCR reaction. Total expression of α/β TCR was assessed by quantification of the constant α-chain as a further control. Results The method was tested by serial dilutions of clonal T-cells in mononuclear cells from healthy volunteers. Calculated percentages were in good correspondence with qRT PCR results demonstrating high reliability. Duplicates showed excellent technical reproducibility. We analyzed blood samples of 20 healthy volunteers for determination of mean and standard deviation for each family. The method was applied both to tissue and blood samples from patients with carcinomas and hematological disorders. Conclusion We introduce a versatile method for the relative quantification of Vβ-families by real time PCR. The experimental strategy described allows the identification of alterations in the Vβ-family repertoire.

Colorectal tumourigenesis is in the majority of cases regarded as a multistep process resulting in chromosomal instability.1 High-frequency microsatellite instability (MSI-H) can be detected in ∼15–20% of all sporadic colorectal cancers (CRCs) and represents the hallmark of the hereditary non-polyposis colorectal cancer (HNPCC) syndrome. CRCs with MSI-H are caused by inactivation of DNA mismatch repair (MMR) genes leading to hundreds of insertion or deletion mutations in short segments of repeated nucleotide sequences, but no chromosomal instability. It has been speculated that abnormal peptides are generated as a consequence of these frameshift mutations, and one would expect a stimulation of the antitumour response by these tumour-associated antigens (TAAs).2 3 In fact, CRCs with MSI-H are associated with a markedly increased number of tumour-infiltrating lymphocytes (TILs) as compared with microsatellite-stable (MSS) tumours, and the favourable prognosis of patients with MSI-H cancer has been attributed to the high content of cytotoxic T cells.4 Over the past few years, CD4+CD25+ regulatory T cells (Treg cells) expressing the transcription factor forkhead box P3 (Foxp3) have been demonstrated to suppress T cell-mediated immunity to TAAs in various human tumours—for example, ovarian cancer.5 In mouse models, depletion of Treg cells using treatment with CD25-, GITR- or CTLA4-specific antibodies has resulted in improved antitumour immunity.6 In human CRC tissue samples, increased numbers of Treg cells as compared with normal mucosa have also been described, with a Treg cell infiltration rate slightly higher in patients without a systemic TAA-specific immune reaction.7 Despite successful induction of an immunological response, current protocols of immunotherapy and vaccination in CRC are not satisfactory.8 The poor response rate in patients with CRC may in part be due to the fact that immunosuppressive mechanisms conferred by Treg cells outweigh the beneficial effects of …

Understanding tumor/host immune interactions may help to fight cancer. Growing knowledge about T cell responses and increasing success of immunotherapeutic approaches have created the need for methods to characterize tumor-directed cellular immune responses. The spectrum of methods reaches from protein-based methods, including tetramers or intracellular flow cytometry, to genetic assays, such as TCR analysis or microarray techniques, further on to functional assays analysing proliferation and microtoxicity. Here, we describe these and further methods and explain their respective application in human tumor immunology.

The application of highly specific mAbs with minimal side effects in cancer therapy was, for a long time, a major goal for many clinical oncologists. Since their arrival in the clinical setting, mAbs have come to represent a standard therapy for some tumors, and have proven to be an important extension to the treatment of a broad spectrum of malignancies. The future development of mAbs for targeting alone (ie, for labeling of tumors) is insufficient for obtaining a suitable clinical response, and adequate clinical success can only be achieved by arming mAbs and targeting them to functionally significant tumor antigens such as tumor growth-related receptors. This review provides an overview of the functional characteristics of mAbs, together with some important examples of their clinical application. While mAbs may not be the 'magic bullets' that many researchers had hoped for, they are nevertheless becoming an indispensable pillar of tumor therapy.

Introduction Although systemic T-cell responses against tumor antigens and tumor infiltration by T cells have been investigated in colorectal cancer (CRC), the initiation of spontaneous immune responses in situ is not well understood. Macrophages and dendritic cells (DC) play an important role as a link between innate and adaptive immune response. The aim of the present study was to analyze macrophage and DC infiltration in CRC and to investigate whether there is a correlation to systemic T-cell response, regulatory T cell (Treg) infiltration, and survival. Methods Immunohistological staining was performed with nine markers for macrophages and DC (CD68, CD163, S100, CD11c, CD208, CD209, CD123, CD1a, Langerin) in 40 colorectal cancer samples from patients, in whom the state of systemic T-cell responses against tumor-associated antigens (TAA) and Treg infiltration had previously been determined. Results All specimens contained cells positive for CD68, CD163, S100 and CD1a in epithelial tumor tissue and tumor stroma. Only a very few (less than median 3/HPF) CD123+, CD1a+, CD11c+, CD 208+, CD209+, or Langerin+ cells were detected in the specimens. Overall, we found a trend towards increased infiltration by S100-positive DC and a significantly increased number of stromal S100-positive DC in patients without T-cell response. There was an increase of stromal S100 DC and CD163 macrophages in limited disease (S100: 11.1/HPF vs. 7.3/HPF, p = 0.046; CD163: 11.0/HPF vs. 8.1/HPF, p = 0.06). We found a significant, positive correlation between S100-positive DC and FOXP3-positive Tregs. Survival in patients with high DC infiltration was significantly better than that in those with low DC infiltration (p < 0.05). Furthermore, we found a trend towards better survival for increased infiltration with CD163-positive macrophages (p = 0.07). Conclusion The present in situ study adds new data to the discussion on the interaction between the innate and adoptive immune system. Our data strongly support the hypothesis that tumor-infiltrating DC are a key factor at the interface between innate and adaptive immune response in malignant disease. Tumor infiltrating S100-positive DC show an inverse relationship with the systemic antigen-specific T-cell response, a positive correlation with regulatory T cells, and a positive association with survival in CRC. These data put tumor-infiltrating DC at the center of the relevant immune response in CRC.

7057 Background: Blinatumomab, a bispecific T-cell engager (BiTE) antibody construct, showed efficacy in r/r ALL in a large phase 2 study (Topp et al. Lancet Oncol 2015;16:57). We evaluated associa...

Metastatic uveal melanoma has a poor prognosis and limited therapeutic options. Proteoglycans are involved in tumor cell invasion and metastatic behavior. The mAbB5 stains a chondroitin sulphate proteoglycan (CSPG) on cutaneous melanoma cells. Here, we compare the B5-staining of CSPG in primaries and metastases of uveal melanoma.Immunohistopathological staining was performed in 15 cutaneous and 39 uveal melanoma samples. A score for intracellular and surface staining was established. B5 staining was compared in primaries and metastases of uveal melanoma using Student's t-test.Eight of 11 (73%) uveal melanoma metastases were positive for B5-staining whereas only 5 of 28 (18%) primary uveal melanoma samples were B5-positive (P0.001). Nine of 15 cutaneous melanoma samples (60%) were B5-positive without significant difference between primary and metastatic lesions. Surface staining was found both on uveal melanoma metastases and cutaneous melanomas.CSPG was expressed significantly more often in metastases than in primaries of uveal melanoma. It potentially may be one factor associated with metastatic spread. Further studies are needed to determine its use as prognostic factor. The mAbB5 may also be a promising tool for immunotherapy due to its strong staining of CSPG on the surface of cutaneous and metastatic uveal melanoma cells.

T-cell trafficking is determined by expression patterns of chemokine receptors. The chemokine receptor CXCR3 is expressed on a subpopulation of type 1 T cells and plays an important role for migration of T cells into inflamed and tumor tissues. Here, we studied the chemokine receptor expression on specific T cells generated against the neoantigen keyhole limpet hemocyanin (KLH) in patients who had been immunized in the context of a tumor peptide vaccination trial with or without the adjuvant granulocyte-macrophage colony-stimulating factor (GM-CSF). In patients immunized in the presence of GM-CSF the fraction of CXCR3(+) KLH-specific T cells was significantly higher than in patients immunized in the absence of GM-CSF (median 45 vs. 20%, P = 0.001). In contrast, the chemokine receptor CCR4, associated with migration to the skin was found in both cohorts on less than 10% of KLH-specific T cells. These results show that CXCR3 expression on vaccine-induced T cells can be modulated by modifying the local vaccine milieu.

Introduction: Treatment of relapsed or refractory DLBCL can be challenging and little progress has been made in recent years. Blinatumomab, a bispecific T-cell engager (BiTE®) antibody construct, engages CD3+ cytotoxic T cells, resulting in T-cell expansion and lysis of CD19+ B cells. In a prior phase 1 study, blinatumomab treatment resulted in an overall response rate (ORR) of 55% in a subset of patients with diffuse large B-cell lymphoma (DLBCL). In the present phase 2 study, we compared stepwise versus flat dosing of blinatumomab, and evaluated its efficacy in patients with relapsed/refractory (r/r) DLBCL. Methods: Eligible patients were ≥18 years of age, had an Eastern Cooperative Oncology Group performance status ≤2 and had DLBCL; patients were refractory to treatment, had relapsed following autologous HSCT, or had relapsed and were ineligible for autologous hematopoietic stem cell transplantation (HSCT). Blinatumomab was administered over 8 weeks by continuous intravenous infusion. In stage 1, stepwise dosing (cohort I: 9, 28, and 112 μg/day after weeks 1, 2, respectively) was compared to constant dosing of 112 μg/day (cohort II). Based on the benefit/risk assessment from stage 1, stepwise dosing (9, 28, and 112 μg/day) was chosen for cohort III in stage 2. Patients achieving response after 8 weeks of treatment could receive a 4-week consolidation cycle after a 4-week treatment-free period. All patients received prophylactic dexamethasone (2 × 20 mg before infusion start and at infusion start; 3 × 8 mg/day for the first 2 days after infusion start and at dose step). The primary endpoint was ORR by Cheson revised response criteria for malignant lymphomas. Response was evaluated by independent radiologic assessment. Results: As of the primary analysis, 25 patients have been enrolled and treated: 9, 2, and 14 in cohorts I, II, and III, respectively. Fifty-six percent of patients were men, and the median age was 66 years (range, 34–85). Seven (28%) patients had received prior autologous HSCT. Blinatumomab was received as a fourth-line systemic therapy following a median (range) of 3 (1-7) prior treatments. Median (interquartile range) duration of exposure for stepwise dosing (cohorts I and III) was 46.8 (22.1−76.9) days. Twenty-one patients were evaluable for response (cohort I, n=7; cohort II, n=1; cohort III, n=13). Four patients were not evaluable for ORR per protocol definition due to early treatment discontinuation (1 patient were disorientation, encephalopathy, aphasia, and epilepsy [n=2 each]). There were no grade 4 or 5 neurologic events. Conclusions: In this phase 2 study, a stepwise dosing regimen (9, 28, and 112 μg/day) was established as the preferred dosing for blinatumomab in DLBCL. Treatment with blinatumomab showed an acceptable safety profile and resulted in objective and durable responses in heavily pretreated patients with r/r DLBCL. Disclosures Viardot: Amgen Inc.: Membership on an entity's Board of Directors or advisory committees, Travel support Other; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Travel support, Travel support Other; Janssen: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Travel support Other. Off Label Use: This presentation will discuss the off-label use of blinatumomab, as this agent is not approved for use by the FDA, EMA or any other regulatory authorities.. Libicher:Amgen Inc.: Consultancy. Degenhard:Amgen Inc.: Equity Ownership; Amgen Research (Munich) GmbH: Employment. Stieglmaier:Amgen Inc.: Equity Ownership; Amgen Research (Munich) GmbH: Employment. Zhang:Amgen Inc.: Employment. Nagorsen:Amgen Inc.: Blinatumomab-related Patents & Royalties, Employment, Equity Ownership. Bargou:Amgen Inc.: Consultancy, Honoraria.

Introduction: In ALL, minimal residual disease (MRD) is defined as the detection of leukemic cells in bone marrow by PCR or flow cytometry in the presence of hematological complete remission (CR). Patients with persistent/recurrent MRD after induction therapy have a higher risk of relapse than those with no detectable MRD. Effective treatment of patients with MRD aims to avoid hematologic relapse, reduce MRD load, and provide a bridge to subsequent HSCT. Blinatumomab, an investigational BiTE® antibody construct, redirects CD3+ T cells to CD19+ target cells, resulting in serial lysis of CD19+ B cells. In a phase 2 study of blinatumomab in 21 patients with MRD+ ALL in first-line treatment, 80% of evaluable patients achieved a complete MRD response. BLAST, a confirmatory single-arm, phase 2 study evaluated efficacy, safety, and tolerability of blinatumomab in patients with MRD+ ALL in a larger population. Methods: Adults (≥18 years) with B-precursor ALL in hematologic CR ( Results: 116 patients enrolled and received blinatumomab. Median (range) age was 45 (18–76) years; 15 (13%) patients were ≥65 years of age. 35% of the patients were treated in second or later remission (Table). As of February 2014, 106 patients had ended treatment: 74 had completed treatment (4 cycles or 1 cycle followed by HSCT) and 32 had discontinued treatment due to AEs, disease relapse, or investigators' decision; 79 patients were still alive and being followed. Three patients were excluded from the efficacy analysis: one had no central lab assay and two had assays with a sensitivity of 5×10-4. Eighty-eight patients (78% [95% CI, 69%–85%]) had a complete MRD response after 1 cycle of treatment. The lower CI bound exceeded 44% (the null hypothesis response rate), confirming that the study met its primary objective. Two additional patients had a complete MRD response after >1 cycle of blinatumomab; across all cycles the complete MRD response rate was 80%. The rate of complete MRD response did not differ significantly across baseline age, sex, line of treatment, and MRD burden categories (Table). All patients experienced ≥1 AE. AEs occurring in ≥20% of patients included pyrexia (88%), headache (38%), tremor (29%), chills (25%), fatigue (24%), nausea (22%) and vomiting (22%). Serious AEs (SAEs) occurred in 60% of patients; 59% and 27% of patients had grade ≥3 and grade ≥4 AEs, respectively. SAEs occurring in ≥5% of patients were pyrexia (15%), tremor (7%), aphasia (5%), encephalopathy (5%) and overdose (5%). Two fatal AEs occurred on treatment: subdural hemorrhage and atypical pneumonia (the latter was deemed treatment-related). Conclusion: This is the largest prospective trial with an experimental compound in MRD+ ALL.Blinatumomab treatment resulted in complete MRD response across multiple patient demographics including patients in second-line treatment and those with high MRD burden. With a complete MRD response rate of 78%, the study met its primary objective. Among patients with a complete MRD response, 98% had a response within the first treatment cycle. In patients with MRD+ ALL following intensive therapy, rapid MRD response induced by blinatumomab has the potential to improve patient outcomes. Figure 1 Figure 1. Disclosures Goekbuget: Amgen Inc.: Consultancy, Honoraria, Research Funding. Off Label Use: This presentation will discuss the off-label use of blinatumomab, as this agent is not approved for use by the FDA, EMA or any other regulatory authorities.. Dombret:Amgen Inc.: Honoraria, Research Funding. Bonifacio:Amgen Inc.: Consultancy. Graux:Amgen Inc.: Honoraria, Membership on an entity's Board of Directors or advisory committees. Buss:Amgen Inc.: Reimbursement for participation in clinical studies, Reimbursement for participation in clinical studies Other; BMS: Travel support, Travel support Other; Novartis: Travel support Other; Pfizer: Reimbursements for participation in clinical studies, Reimbursements for participation in clinical studies Other. Bruggemann:Amgen Inc.: Consultancy, Research Funding. Stieglmaier:Amgen Inc.: Equity Ownership; Amgen Research (Munich) GmbH: Employment. Wessels:Amgen Inc.: Equity Ownership; Amgen Research (Munich) GmbH: Employment. Haddad:Amgen Ltd.: Employment. Zugmaier:Amgen Research (Munich) GmbH: Employment; Amgen Inc.: Equity Ownership. Nagorsen:Amgen Inc.: Employment, Equity Ownership, Related to blinatumomab Patents & Royalties. Bargou:Amgen Inc.: Consultancy, Honoraria.

Tumor immunology has made rapid progress since the discovery of tumor-associated antigens. Antigen-specific T cell responses can now be reliably induced by vaccination. Some preliminary studies suggest that induction of a specific T cell response correlates with the clinical response. Several methods have been successfully utilized for monitoring TAA-specific T cells in tumor patients. The ELISPOT assay, cytokine flow cytometry, and tetramers have emerged as standard first-line T cell assays. Further assays complement the analysis for specific scientific questions. T cell analysis is not yet a defined surrogate marker for clinical efficacy. However, it indicates the immunological potency of a vaccine. A detailed T cell analysis can shed light on the T cell phenotype and function and may thus promote the development of clinically more effective vaccines.