Frank J. Hsu

Clinical Outcome of Lymphoma Patients After Idiotype Vaccination Is Correlated With Humoral Immune Response and Immunoglobulin G Fc Receptor Genotype

PURPOSE The unique immunoglobulin idiotype (Id) expressed by each B-cell lymphoma is a target for immunotherapy. Vaccination with Id induces humoral and/or cellular anti-Id immune responses. However, the clinical impact of these anti-Id immune responses is unknown. We and others have previously reported that immunoglobulin G Fc receptor (FcgammaR) polymorphisms predict the clinical response of lymphoma patients to passive anti-CD20 antibody infusions. In this study, we tested whether anti-Id immune responses or FcgammaR polymorphisms associate with clinical outcome of patients who received Id vaccination. PATIENTS AND METHODS We analyzed 136 patients with follicular lymphoma who had received Id vaccination. The anti-Id immune responses were measured and FcgammaRIIIa and FcgammaRIIa polymorphisms were determined and correlated with clinical outcome for these patients. RESULTS Patients who mounted humoral immune responses had a longer progression-free survival (PFS) than those who did not (8.21 v 3.38 years; P = .018). Patients with FcgammaRIIIa 158 valine/valine (V/V) genotype also had a longer PFS than those with valine/phenylalanine (V/F) or phenylalanine/phenylalanine (F/F) genotypes (V/V, 8.21 v V/F, 3.38 years; P = .004; v F/F, 4.47 years; P = .035). Multivariate analysis using the Cox proportional hazards model showed that V/V genotype and humoral immune responses were independent positive predictors for PFS. CONCLUSION This study is the first to identify the predictive value of FcgammaR polymorphism on clinical outcome in patients who received active immunotherapy with tumor antigen vaccines. Our results imply that the antibodies induced against a tumor antigen are beneficial and that FcgammaR-bearing cells mediate an antitumor effect by killing antibody-coated tumor cells.

The radioisotope contributes significantly to the activity of radioimmunotherapy

Purpose: A multicenter, randomized study was undertaken to estimate the single agent activity of Tositumomab and to determine the contribution of radioisotope-labeling with 131I to activity and toxicity by comparing treatment outcomes for Tositumomab and Iodine I 131 Tositumomab (BEXXAR) to an equivalent total dose of unlabeled Tositumomab. Experimental Design: Seventy-eight patients with refractory/relapsed non-Hodgkin’s lymphoma were randomized to either unlabeled Tositumomab or Iodine I 131 Tositumomab. Patients progressing after unlabeled Tositumomab could cross over to receive Iodine I 131 Tositumomab. The median follow-up at analysis was 42.6 months (range 1.9 to 71.5 months). Results: Responses in the Iodine I 131 Tositumomab versus unlabeled Tositumomab groups: overall response 55% versus 19% (P = 0.002); complete response 33% versus 8% (P = 0.012); median duration of overall response not reached versus 28.1 months (95% confidence interval: 7.6, not reached); median duration of complete response not reached in either arm; and median TTP 6.3 versus 5.5 months (P = 0.031), respectively. Of the patients who had a complete response after initial Iodine I 131 Tositumomab therapy, 71% (10 of 14) continued in complete response at 29.8 to 71.1 months. Two patients who achieved a complete response after unlabeled Tositumomab had ongoing responses at 48.1 to 56.9 months. Nineteen patients received Iodine I 131 Tositumomab crossover therapy. Responses after crossover versus prior response to unlabeled Tositumomab were as follows: complete response rates of 42% versus 0% (P = 0.008); overall response 68% versus 16% (P = 0.002); median durations of overall response 12.6 versus 7.6 months (P = 0.001); and median TTP 12.4 versus 5.5 months (P = 0.01), respectively. Hematologic toxicity was more severe and nonhematologic adverse events were more frequent after Iodine I 131 Tositumomab than after Tositumomab alone. Elevated thyrotropin occurred in 5% of patients. Seroconversion to human antimurine antibody after Iodine I 131 Tositumomab, unlabeled Tositumomab, and Iodine I 131 Tositumomab-crossover was 27%, 19%, and 0%, respectively. Conclusions: Unlabeled Tositumomab showed single agent activity, but in this direct comparison, all of the therapeutic outcome measures were significantly enhanced by the conjugation of 131I to Tositumomab.

Phase I Study of GC1008 (Fresolimumab): A Human Anti-Transforming Growth Factor-Beta (TGFβ) Monoclonal Antibody in Patients with Advanced Malignant Melanoma or Renal Cell Carcinoma

Background In advanced cancers, transforming growth factor-beta (TGFβ) promotes tumor growth and metastases and suppresses host antitumor immunity. GC1008 is a human anti-TGFβ monoclonal antibody that neutralizes all isoforms of TGFβ. Here, the safety and activity of GC1008 was evaluated in patients with advanced malignant melanoma and renal cell carcinoma. Methods In this multi-center phase I trial, cohorts of patients with previously treated malignant melanoma or renal cell carcinoma received intravenous GC1008 at 0.1, 0.3, 1, 3, 10, or 15 mg/kg on days 0, 28, 42, and 56. Patients achieving at least stable disease were eligible to receive Extended Treatment consisting of 4 doses of GC1008 every 2 weeks for up to 2 additional courses. Pharmacokinetic and exploratory biomarker assessments were performed. Results Twenty-nine patients, 28 with malignant melanoma and 1 with renal cell carcinoma, were enrolled and treated, 22 in the dose-escalation part and 7 in a safety cohort expansion. No dose-limiting toxicity was observed, and the maximum dose, 15 mg/kg, was determined to be safe. The development of reversible cutaneous keratoacanthomas/squamous-cell carcinomas (4 patients) and hyperkeratosis was the major adverse event observed. One malignant melanoma patient achieved a partial response, and six had stable disease with a median progression-free survival of 24 weeks for these 7 patients (range, 16.4–44.4 weeks). Conclusions GC1008 had no dose-limiting toxicity up to 15 mg/kg. In patients with advanced malignant melanoma and renal cell carcinoma, multiple doses of GC1008 demonstrated acceptable safety and preliminary evidence of antitumor activity, warranting further studies of single agent and combination treatments. Trial Registration Clinicaltrials.gov NCT00356460

Transplanted CD34+ Cell Dose Is Associated with Long-Term Platelet Count Recovery following Autologous Peripheral Blood Stem Cell Transplant in Patients with Non-Hodgkin Lymphoma or Multiple Myeloma

Autologous hematopoietic stem cell transplantation (ASCT) is an established treatment for patients with hematologic malignancies, yet the impact of transplanted CD34(+) cell dose on clinical outcomes is unresolved. We conducted post hoc analyses of transplanted CD34(+) cell dose and hematopoietic recovery following ASCT in 438 patients with non-Hodgkin lymphoma (NHL) or multiple myeloma (MM), using data from 2 multicenter phase 3 clinical studies that compared plerixafor plus granulocyte-colony stimulating factor (G-CSF) versus placebo plus G-CSF as stem cell mobilization regimens. Days to engraftment and the proportion of patients who reached predetermined blood count thresholds were compared across 3 CD34(+) cell dose levels: 2-4 × 10(6) cells/kg, 4-6 × 10(6) cells/kg, and >6 × 10(6) cells/kg, regardless of mobilization treatment. Short-term neutrophil and platelet engraftment times were similar regardless of cell dose. A significant linear trend was observed between transplanted CD34(+) cell dose and the proportion of patients with platelet count >150 × 10(9)/L at 100 days (P < .001), 6 months (P = .026), and 12 months (P = .020) in patients with NHL, and at 100 days in patients with MM (P = .004). A linear trend was also observed between transplanted cell dose and the proportion of patients with platelet count >100 × 10(9)/L at 100 days (P < .001) and 6 months (P = .023) in patients with NHL. A higher cell dose was associated with a lower percentage of NHL patients requiring red blood cell transfusions (P = .006). Our analyses confirm previous findings that transplanted CD34(+) cell dose may be associated with better long-term platelet recovery after ASCT.

CTLA4 blockade maximizes antitumor T-cell activation by dendritic cells presenting idiotype protein or opsonized anti-CD20 antibody-coated lymphoma cells

CTLA4 is a negative regulator of the costimulatory signals induced by the interaction of CD28 on T cells and B7 on dendritic cells (DCs). Antibodies (Abs) against CTLA4 can block its function and increase the activation of T cells primed to recognize antigens. The effect of CTLA4 blockade on the cross-presentation of tumor antigens by DCs to T cells was examined. Immune T cells and DC precursors were collected from patients receiving idiotype protein-pulsed DC vaccines, exposed to antigen, and examined for antitumor activity by measuring intracellular cytokine production by FACS. Idiotype-specific activation occurred in CD8+ and CD4+ T-cell populations and was up to 58 fold higher with CTLA4 blockade. These T cells could be expanded quickly and maintained tumor cytolytic activity. T-cell responses to whole tumor cell-pulsed DCs were then examined. DCs contain Fc receptors and efficiently phagocytose lymphoma cells when coated with opsonizing anti-CD20 Abs. Within a few hours, DCs ingested tumor cells and labeled proteins were observed in the cytoplasm. When anti-CD20 Ab-coated tumor-pulsed DCs were used in combination with CTLA4 blockade, up to 15 fold higher activation of Id-specific CD8+ and 3 fold higher CD4+ T cells resulted. Thus, CTLA4 blockade can enhance the measurement of Ag-specific T-cell responses and the expansion of T cells for clinical studies. In addition, the combination of CTLA4 blockade and Ab targeting of tumor to DCs is an effective method for the cross-presentation of tumor cell antigens.

Plerixafor Plus Granulocyte Colony-Stimulating Factor versus Placebo Plus Granulocyte Colony-Stimulating Factor for Mobilization of CD34+ Hematopoietic Stem Cells in Patients with Multiple Myeloma and Low Peripheral Blood CD34+ Cell Count: Results of a Subset Analysis of a Randomized Trial

Preapheresis peripheral blood (PB) CD34(+) cell count is a strong predictor of hematopoietic stem cell (HSC) mobilization and is routinely used to optimize the timing, cost, and success of HSC collection in patients with multiple myeloma. However, a uniform PB CD34(+) cell count that predicts mobilization failure has not been defined, resulting in the development of institute-specific algorithms for mobilization, particularly regarding the decision of when to use the novel stem cell mobilization agent plerixafor. In this post hoc analysis, we evaluated the mobilization efficacy of plerixafor plus granulocyte colony-stimulating factor (G-CSF) versus placebo plus G-CSF in patients with multiple myeloma, stratified by preapheresis PB CD34(+) cell count: <10, <15, <20, and ≥20 cells/μL. Regardless of the PB CD34(+) cell count, the total yield of CD34(+) cells from apheresis was significantly higher in the plerixafor group than in the placebo group, and significantly more patients in the plerixafor group collected the minimum (≥2 × 10(6) cells/kg) and optimum (≥6 × 10(6) cells/kg) stem cell yields on each day of apheresis. As a corollary, the greater stem cell collection in plerixafor-treated patients resulted in the need for significantly fewer days of apheresis to reach minimum and optimum cell doses across all cell count groups. For all CD34(+) cell count groups, the proportion of patients proceeding to transplantation and the median time to platelet and neutrophil engraftment were similar in the plerixafor and placebo groups. Our findings demonstrate that in patients with multiple myeloma who might be predicted to fail mobilization based on low PB CD34(+) cell count, the addition of plerixafor to G-CSF allows for collection of the minimal and optimal cell doses in a greater proportion of patients compared with G-CSF alone. In addition, plerixafor plus G-CSF significantly improves the likelihood of optimal HSC collection in patients with higher preapheresis PB CD34(+) cell counts (≥20 cells/μL) compared with placebo plus G-CSF. Collectively, this analysis of predicted poor mobilizers validates the superiority of plerixafor plus G-CSF compared with G-CSF alone, which had been demonstrated previously in the overall patient population.

TGF-β-Neutralizing Antibody 1D11 Enhances Cytarabine-Induced Apoptosis in AML Cells in the Bone Marrow Microenvironment.

Hypoxia and interactions with bone marrow (BM) stromal cells have emerged as essential components of the leukemic BM microenvironment in promoting leukemia cell survival and chemoresistance. High levels of transforming growth factor beta 1 (TGFβ1) produced by BM stromal cells in the BM niche regulate cell proliferation, survival, and apoptosis, depending on the cellular context. Exogenous TGFβ1 induced accumulation of acute myeloid leukemia (AML) cells in a quiescent G0 state, which was further facilitated by the co-culture with BM-derived mesenchymal stem cells (MSCs). In turn, TGFβ-neutralizing antibody 1D11 abrogated rhTGFβ1 induced cell cycle arrest. Blocking TGFβ with 1D11 further enhanced cytarabine (Ara-C)–induced apoptosis of AML cells in hypoxic and in normoxic conditions. Additional constituents of BM niche, the stroma-secreted chemokine CXCL12 and its receptor CXCR4 play crucial roles in cell migration and stroma/leukemia cell interactions. Treatment with 1D11 combined with CXCR4 antagonist plerixafor and Ara-C decreased leukemia burden and prolonged survival in an in vivo leukemia model. These results indicate that blockade of TGFβ by 1D11 and abrogation of CXCL12/CXCR4 signaling may enhance the efficacy of chemotherapy against AML cells in the hypoxic BM microenvironment.

Relevance and Clinical Implications of Tumor Cell Mobilization in the Autologous Transplant Setting

Autologous transplantation of peripheral blood (PB) hematopoietic stem cells (HSCs) is a widely used strategy for reconstitution of blood cells following high-dose chemotherapy for hematologic malignancies such as multiple myeloma (MM), non-Hodgkin lymphoma (NHL), and acute myeloid leukemia (AML), among others. Stem cells for transplantation are usually obtained from PB after treatment with chemotherapy with or without cytokine, usually granulocyte-colony stimulating factor (G-CSF), or after treatment with cytokine alone. The use of autologous peripheral blood stem cells (PBSCs) for transplantation is associated with the risk of contamination of the graft with tumor cells; whether this impacts response rates, progression-free survival (PFS), and overall survival (OS) is still debatable. This review summarizes the controversy surrounding tumor cell mobilization (TCM), the complexity of detection of minimal residual diseases, the available diagnostic tools, differences in TCM with available mobilization regimens, and the potential effect of TCM on clinical outcome. Collectively, these data suggest that new treatment paradigms to manage hematologic malignancies, such as MM, NHL, and AML, are needed and should focus on increasing the chemosensitivity of the tumor and eliminating residual disease.

First-in-Human Treatment With a Dendritic Cell-targeting Lentiviral Vector-expressing NY-ESO-1, LV305, Induces Deep, Durable Response in Refractory Metastatic Synovial Sarcoma Patient

Effective induction of antitumor T cells is a pivotal goal of cancer immunotherapy. To this end, lentiviral vectors (LV) are uniquely poised to directly prime CD8 T-cell responses via transduction of dendritic cells in vivo and have shown promise as active cancer therapeutics in preclinical tumor models. However, until now, significant barriers related to production and regulation have prevented their widespread use in the clinic. We developed LV305, a dendritic cell-targeting, integration-deficient, replication incompetent LV from the ZVex platform, encoding the full-length cancer-testis antigen NY-ESO-1. LV305 is currently being evaluated in phase 1 and 2 trials in metastatic recurrent cancer patients with NY-ESO-1 positive solid tumors as a single agent and in combination with anti-PD-L1. Here we report on the first patient treated with LV305, a young woman with metastatic, recurrent, therapy-refractive NY-ESO-1+ synovial sarcoma. The patient developed a robust NY-ESO-1-specific CD4+ and CD8+ T-cell response after 3 intradermal injections with LV305, and subsequently over 85% disease regression that is continuing for >2.5 years posttherapy. No adverse events >grade 2 occurred. This case demonstrates that LV305 can be safely administered and has the potential to induce a significant clinical benefit and immunologic response in a patient with advanced stage cancer.Effective induction of antitumor T cells is a pivotal goal of cancer immunotherapy. To this end, lentiviral vectors (LV) are uniquely poised to directly prime CD8 T-cell responses via transduction of dendritic cells in vivo and have shown promise as active cancer therapeutics in preclinical tumor models. However, until now, significant barriers related to production and regulation have prevented their widespread use in the clinic. We developed LV305, a dendritic cell-targeting, integration-deficient, replication incompetent LV from the ZVex platform, encoding the full-length cancer-testis antigen NY-ESO-1. LV305 is currently being evaluated in phase 1 and 2 trials in metastatic recurrent cancer patients with NY-ESO-1 positive solid tumors as a single agent and in combination with anti-PD-L1. Here we report on the first patient treated with LV305, a young woman with metastatic, recurrent, therapy-refractive NY-ESO-1 synovial sarcoma. The patient developed a robust NY-ESO-1-specific CD4 and CD8 T-cell response after 3 intradermal injections with LV305, and subsequently over 85% disease regression that is continuing for >2.5 years posttherapy. No adverse events >grade 2 occurred. This case demonstrates that LV305 can be safely administered and has the potential to induce a significant clinical benefit and immunologic response in a patient with advanced stage cancer.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. http://creativecommons.org/licenses/by-nc-nd/4.0/.

Prolonged disease-free survival and overall survival with CVP alternating with fludarabine in advanced follicular lymphoma†

Cyclophosphamide and fludarabine are highly active in treating follicular lymphoma (FL). However, many cyclophosphamide and fludarabine combination regimens, although highly effective, exhibited severe infectious toxicities including toxic death [1-7]. We designed a novel sequential regimen consisting of CVP (cyclophosphamide 400 mg/m 2 PO d1-5, vincristine 2 mg d1, prednisone 100 mg/m 2 d1-5) alternating with fludarabine (25 mg/m 2 IV d1-5) as induction chemotherapy for idiotype vaccination, with a goal of obtaining a higher quality of tumor debulking before vaccination. Herein, we report the safety and efficacy of this regimen. Thirty-four consecutive untreated patients with FL received this regimen. Toxicities were modest with no severe infections or toxic deaths. Complete response/unconfirmed complete response (CR/CRu) was achieved in 18 patients (53%) and PR in 38%. At a median follow-up of 12 years, overall survival (OS), event-free survival (EFS), time to progression (TTP), and disease free survival (DFS) were 85, 37, 38, and 70%, respectively. Among a cohort of historical controls with similar characteristics receiving CVP, the CR rate was 34%, 12-year OS, EFS, TTP, and DFS were 64, 20, 21, and 37%, respectively. Thus, CVP/F exhibited favorable safety profile while maintaining the excellent efficacy of combining cyclophosphamide and fludarabine and warrants further evaluation in combination with rituximab.