Nicole A. Aqui

Restoration of immunity in lymphopenic individuals with cancer by vaccination and adoptive T-cell transfer

Immunodeficiency is a barrier to successful vaccination in individuals with cancer and chronic infection. We performed a randomized phase 1/2 study in lymphopenic individuals after high-dose chemotherapy and autologous hematopoietic stem cell transplantation for myeloma. Combination immunotherapy consisting of a single early post-transplant infusion of in vivo vaccine-primed and ex vivo costimulated autologous T cells followed by post-transplant booster immunizations improved the severe immunodeficiency associated with high-dose chemotherapy and led to the induction of clinically relevant immunity in adults within a month after transplantation. Immune assays showed accelerated restoration of CD4 T-cell numbers and function. Early T-cell infusions also resulted in significantly improved T-cell proliferation in response to antigens that were not contained in the vaccine, as assessed by responses to staphylococcal enterotoxin B and cytomegalovirus antigens (P < 0.05). In the setting of lymphopenia, combined vaccine therapy and adoptive T-cell transfer fosters the development of enhanced memory T-cell responses.

Treatment of PTLD with Rituximab or Chemotherapy

Information regarding treatment of post‐transplant lymphoproliferative disease (PTLD) beyond reduction in immunosuppression (RI) is limited. We retrospectively evaluated patients receiving rituximab and/or chemotherapy for PTLD for response, time to treatment failure (TTF) and overall survival (OS). Thirty‐five patients met inclusion criteria. Twenty‐two underwent rituximab treatment, with overall response rate (ORR) 68%. Median TTF was not reached at 19 months and estimated OS was 31 months. In univariable analysis, Epstein‐Barr virus (EBV) positivity predicted response and TTF. LDH elevation predicted shorter OS. No patient died of rituximab toxicity and all patients who progressed underwent further treatment with chemotherapy. Twenty‐three patients received chemotherapy. ORR was 74%, median TTF was 10.5 months and estimated OS was 42 months. Prognostic factors for response included stage, LDH and allograft involvement by tumor. These factors and lack of complete response (CR) predicted poor survival. Twenty‐six percent of the patients receiving chemotherapy died of toxicity. Rituximab and chemotherapy are effective in patients with PTLD who fail or do not tolerate RI. While rituximab is well tolerated, toxicity of chemotherapy is marked. PTLD patients requiring therapy beyond RI should be considered for rituximab, especially with EBV‐positive disease. Chemotherapy should be reserved for patients who fail rituximab, have EBV‐negative tumors or need a rapid response.

CD25 Blockade Depletes and Selectively Reprograms Regulatory T Cells in Concert with Immunotherapy in Cancer Patients

CD25 monoclonal antibody therapy rapidly and durably depletes Tregs in cancer patients through a mechanism consistent with reprogramming. Rehabilitating Tregs In A Clockwork Orange, a young criminal undergoes a controversial rehabilitation therapy that reprograms him to become sick at even the thought of violence. Indeed, rehabilitation, although carried out with much less extreme measures, is a critical strategy for reforming many types of bad apples. Rech et al. now extend this concept to the delinquent regulatory T cells (Tregs) that suppress antitumor immune responses. Tregs perform a critical role in healthy individuals—they prevent immune cells from the attacks on their host that causes autoimmunity. However, in the tumor microenvironment, Tregs are insidious—inhibiting immune responses against the tumor itself. Rech et al. hypothesized that daclizumab, a Food and Drug Administration–approved antibody to CD25, which is expressed on Tregs, could deplete Tregs and restore the antitumor immune response. They found in vitro that Tregs treated with daclizumab lost their suppressive function and secreted interferon-γ, which is consistent with reprogramming to effector T cells. They then treated patients with daclizumab in conjunction with an experimental vaccine for metastatic breast cancer. These patients had fewer Tregs and increased levels of vaccine antigen-specific effector T cell responses. Despite the loss of Tregs, these patients did not develop autoimmunity. Although these are still early studies, they provide hope that daclizumab may help to restore antitumor immunity without inducing autoimmunity. Regulatory T cells (Tregs) are key mediators of immune tolerance and feature prominently in cancer. Depletion of CD25+ FoxP3+ Tregs in vivo may promote T cell cancer immunosurveillance, but no strategy to do so in humans while preserving immunity and preventing autoimmunity has been validated. We evaluated the Food and Drug Administration–approved CD25-blocking monoclonal antibody daclizumab with regard to human Treg survival and function. In vitro, daclizumab did not mediate antibody-dependent or complement-mediated cytotoxicity but rather resulted in the down-regulation of FoxP3 selectively among CD25high CD45RAneg Tregs. Moreover, daclizumab-treated CD45RAneg Tregs lost suppressive function and regained the ability to produce interferon-γ, consistent with reprogramming. To understand the impact of daclizumab on Tregs in vivo, we performed a clinical trial of daclizumab in combination with an experimental cancer vaccine in patients with metastatic breast cancer. Daclizumab administration led to a marked and prolonged decrease in Tregs in patients. Robust CD8 and CD4 T cell priming and boosting to all vaccine antigens were observed in the absence of autoimmunity. We conclude that CD25 blockade depletes and selectively reprograms Tregs in concert with active immune therapy in cancer patients. These results suggest a mechanism to target cancer-associated Tregs while avoiding autoimmunity.

CD28 Costimulation Is Essential for Human T Regulatory Expansion and Function

The costimulatory requirements required for peripheral blood T regulatory cells (Tregs) are unclear. Using cell-based artificial APCs we found that CD28 but not ICOS, OX40, 4-1BB, CD27, or CD40 ligand costimulation maintained high levels of Foxp3 expression and in vitro suppressive function. Only CD28 costimulation in the presence of rapamycin consistently generated Tregs that consistently suppressed xenogeneic graft-vs-host disease in immunodeficient mice. Restimulation of Tregs after 8–12 days of culture with CD28 costimulation in the presence of rapamycin resulted in >1000-fold expansion of Tregs in <3 wk. Next, we determined whether other costimulatory pathways could augment the replicative potential of CD28-costimulated Tregs. We observed that while OX40 costimulation augmented the proliferative capacity of CD28-costimulated Tregs, Foxp3 expression and suppressive function were diminished. These studies indicate that the costimulatory requirements for expanding Tregs differ from those for T effector cells and, furthermore, they extend findings from mouse Tregs to demonstrate that human postthymic Tregs require CD28 costimulation to expand and maintain potent suppressive function in vivo.

Combination immunotherapy using adoptive T-cell transfer and tumor antigen vaccination on the basis of hTERT and survivin after ASCT for myeloma

In a phase 1/2 two-arm trial, 54 patients with myeloma received autografts followed by ex vivo anti-CD3/anti-CD28 costimulated autologous T cells at day 2 after transplantation. Study patients positive for human leukocyte antigen A2 (arm A, n = 28) also received pneumococcal conjugate vaccine immunizations before and after transplantation and a multipeptide tumor antigen vaccine derived from the human telomerase reverse transcriptase and the antiapoptotic protein survivin. Patients negative for human leukocyte antigen A2 (arm B, n = 26) received the pneumococcal conjugate vaccine only. Patients exhibited robust T-cell recoveries by day 14 with supraphysiologic T-cell counts accompanied by a sustained reduction in regulatory T cells. The median event-free survival (EFS) for all patients is 20 months (95% confidence interval, 14.6-24.7 months); the projected 3-year overall survival is 83%. A subset of patients in arm A (36%) developed immune responses to the tumor antigen vaccine by tetramer assays, but this cohort did not exhibit better EFS. Higher posttransplantation CD4(+) T-cell counts and a lower percentage of FOXP3(+) T cells were associated with improved EFS. Patients exhibited accelerated polyclonal immunoglobulin recovery compared with patients without T-cell transfers. Adoptive transfer of tumor antigen vaccine-primed and costimulated T cells leads to augmented and accelerated cellular and humoral immune reconstitution, including antitumor immunity, after autologous stem cell transplantation for myeloma. This study was registered at www.clinicaltrials.gov as NCT00499577.

Rapid Immune Recovery and Graft-versus-Host Disease ^ like Engraftment Syndrome following Adoptive Transfer of Costimulated Autologous T Cells

Purpose: Previously, we showed that adoptive transfer of in vivo vaccine-primed and ex vivo (anti-CD3/anti-CD28) costimulated autologous T cells (ex-T) at day +12 after transplant increased CD4 and CD8 T-cell counts at day +42 and augmented vaccine-specific immune responses in patients with myeloma. Here, we investigated the safety and kinetics of T-cell recovery after infusing ex-T at day +2 after transplant. Experimental Design: In this phase I/II two-arm clinical trial, 50 patients with myeloma received autografts after high-dose melphalan followed by infusions of ex-T at day +2 after transplant. Patients also received pretransplant and posttransplant immunizations using a pneumococcal conjugate vaccine only (arm B; n = 24) or the pneumococcal conjugate vaccine plus an HLA-A2–restricted multipeptide vaccine for HLA-A2+ patients (arm A; n = 26). Results: The mean number of T cells infused was 4.26 × 1010 (range, 1.59-5.0). At day 14 after transplant, the median CD3, CD4, and CD8 counts were 4,198, 1,545, and 2,858 cells/μL, respectively. Interleukin (IL)-6 and IL-15 levels increased early after transplant and IL-15 levels correlated significantly to day 14 T-cell counts. Robust vaccine-specific B- and T-cell responses were generated. T-cell infusions were well tolerated with no effect on hematopoietic recovery. Eight patients (16%) developed a T-cell “engraftment syndrome” characterized by diarrhea and fever that was clinically and histopathologically indistinguishable from grade 1 to 3 acute graft-versus-host disease (GVHD) of the gastrointestinal tract (seven patients) and/or grade 1 to 2 cutaneous GVHD (four patients). Conclusions: Adoptive T-cell transfers achieve robust T-cell recovery early after transplant and induce moderate-to-severe autologous GVHD in a subset of patients.

Combination Immunotherapy after ASCT for Multiple Myeloma Using MAGE-A3/Poly-ICLC Immunizations Followed by Adoptive Transfer of Vaccine-Primed and Costimulated Autologous T Cells

Purpose: Myeloma-directed cellular immune responses after autologous stem cell transplantation (ASCT) may reduce relapse rates. We studied whether coinjecting the TLR-3 agonist and vaccine adjuvant Poly-ICLC with a MAGE-A3 peptide vaccine was safe and would elicit a high frequency of vaccine-directed immune responses when combined with vaccine-primed and costimulated autologous T cells. Experimental Design: In a phase II clinical trial (NCT01245673), we evaluated the safety and activity of ex vivo expanded autologous T cells primed in vivo using a MAGE-A3 multipeptide vaccine (compound GL-0817) combined with Poly-ICLC (Hiltonol), granulocyte macrophage colony-stimulating factor (GM-CSF) ± montanide. Twenty-seven patients with active and/or high-risk myeloma received autografts followed by anti-CD3/anti-CD28–costimulated autologous T cells, accompanied by MAGE-A3 peptide immunizations before T-cell collection and five times after ASCT. Immune responses to the vaccine were evaluated by cytokine production (all patients), dextramer binding to CD8+ T cells, and ELISA performed serially after transplant. Results: T-cell infusions were well tolerated, whereas vaccine injection site reactions occurred in >90% of patients. Two of nine patients who received montanide developed sterile abscesses; however, this did not occur in the 18 patients who did not receive montanide. Dextramer staining demonstrated MAGE-A3–specific CD8 T cells in 7 of 8 evaluable HLA-A2+ patients (88%), whereas vaccine-specific cytokine-producing T cells were generated in 19 of 25 patients (76%). Antibody responses developed in 7 of 9 patients (78%) who received montanide and only weakly in 2 of 18 patients (11%) who did not. The 2-year overall survival was 74% [95% confidence interval (CI), 54%–100%] and 2-year event-free survival was 56% (95% CI, 37%–85%). Conclusions: A high frequency of vaccine-specific T-cell responses were generated after transplant by combining costimulated autologous T cells with a Poly-ICLC/GM-CSF–primed MAGE-A3 vaccine. Clin Cancer Res; 20(5); 1355–65. ©2013 AACR.

Combined lenalidomide, low‐dose dexamethasone, and rituximab achieves durable responses in rituximab‐resistant indolent and mantle cell lymphomas

Lenalidomide is an immunomodulatory drug with effects on the immune system that may enhance antibody‐dependent cell‐mediated cytotoxicity and reverse tumor‐induced immune suppression. Furthermore, single‐agent lenalidomide has therapeutic activity in relapsed/refractory B‐cell lymphomas. These immunologic effects potentially may enhance the action of rituximab.

Posttransplant lymphoproliferative disorder in adult liver transplant recipients: A report of seventeen cases

Posttransplant lymphoproliferative disorder (PTLD) is a major complication of liver transplantation, but previous descriptions have been limited to case reports and small case series. We report a retrospective analysis of 17 consecutive cases of PTLD associated with liver transplantation. The median age at PTLD diagnosis was 47 years (range 19 – 63) with a median time of 25 months from liver transplantation to PTLD diagnosis (range 3 – 75). PTLD location was frequently extranodal (71%) and involved the transplanted liver (41%). PTLD histology consisted of nine (53%) monomorphic and eight (47%) polymorphic disease. EBV was present by in situ hybridization in 11 (79%) of 14 cases evaluated. Initial therapy included reduction in immunosuppression (RI) alone in 13 (76%) of 17 patients, resulting in 6 (46%) complete responses (CR) and 7 (54%) progressive disease (PD). Monoclonal CD20 antibody (rituximab) and CHOP chemotherapy were used as initial therapy or as second line after RI failure. Currently, five patients (29%) are alive in CR. Although detection and treatment of PTLD in liver transplant recipients remains problematic and upfront mortality is still high, long-term survival is possible. Further studies are necessary to better define treatment strategies.

Transfer of influenza vaccine–primed costimulated autologous T cells after stem cell transplantation for multiple myeloma leads to reconstitution of influenza immunity: results of a randomized clinical trial

Severe immune deficiency follows autologous stem cell transplantation for multiple myeloma and is associated with significant infectious morbidity. This study was designed to evaluate the utility of a pretransplantation vaccine and infusion of a primed autologous T-cell product in stimulating specific immunity to influenza. Twenty-one patients with multiple myeloma were enrolled from 2007 to 2009. Patients were randomly assigned to receive an influenza-primed autologous T-cell product or a nonspecifically primed autologous T-cell product. The study endpoint was the development of hemagglutination inhibition titers to the strain-specific serotypes in the influenza vaccine. Enzyme-linked immunospot assays were performed to confirm the development of influenza-specific B-cell and T-cell immunity. Patients who received the influenza-primed autologous T-cell product were significantly more likely to seroconvert in response to the influenza vaccine (P = .001). Seroconversion was accompanied by a significant B-cell response. No differences were observed in the global quantitative recovery of T-cell and B-cell subsets or in global T-cell and B-cell function. The provision of a primed autologous T-cell product significantly improved subsequent influenza vaccine responses. This trial was registered at www.clinicaltrials.gov as #NCT00499577.