Glofitamab stimulates immune cell infiltration of CNS tumors and induces clinical responses in secondary CNS lymphoma.

Although CD20xCD3 bispecific antibodies are effective against systemic B-cell lymphomas, their efficacy in CNS lymphoma is unknown. Here, we report the CD20xCD3 bispecific, glofitamab, penetrates the blood-brain barrier, stimulates immune-cell infiltration of CNS tumors, and induces responses in CNS lymphoma.

Pembrolizumab plus vorinostat induces responses in patients with Hodgkin lymphoma refractory to prior PD-1 blockade.

This phase 1 study evaluated the addition of vorinostat to pembrolizumab in patients with relapsed/refractory (RR) classical Hodgkin lymphoma (cHL), diffuse large B-cell lymphoma, and follicular lymphoma. We report the results in cases of cHL. Adult patients with RR cHL who had received ≥1 prior lines of therapy and were ineligible for transplantation were treated in a dose-escalation cohort with 2 dose levels (DLs) and then on an expansion cohort at the recommended phase 2 dose (RP2D) in 21-day cycles. Vorinostat 100 mg twice a day (DL1) and 200 mg twice a day (DL2) was administered orally from days 1 to 5 and 8 to 12; all patients received pembrolizumab 200 mg IV every 3 weeks. The primary end point was safety and determination of RP2D. In total, 32 patients with cHL were enrolled, including 30 at DL2 (RP2D); 78% had received prior anti-programmed cell death 1 (anti-PD-1) therapy, and 56% were PD-1 refractory. Grade ≥3 adverse events (AEs) included hypertension (9%), neutropenia (9%), hypophosphatemia (9%), thrombocytopenia (6%), and lymphopenia (6%). Immune-related AEs included grade 1 or 2 thyroiditis (13%), grade 1 rash (6%), and grade 3 esophagitis/duodenitis (3%). The overall response rate (ORR) was 72% and complete response (CR) rate was 34%. Patients refractory to prior PD-1 blockade (n = 18) had ORR and CR rates of 56% and 11%, respectively. Pembrolizumab and vorinostat was well tolerated with a high ORR rate in RR cHL including in anti-PD-1-refractory disease. This trial was registered at www.clinicaltrials.gov as #NCT03150329.

CD5 Binds to Interleukin-6 and Induces a Feed-Forward Loop with the Transcription Factor STAT3 in B Cells to Promote Cancer.

The participation of a specific subset of B cells and how they are regulated in cancer is unclear. Here, we demonstrate that the proportion of CD5(+) relative to interleukin-6 receptor α (IL-6Rα)-expressing B cells was greatly increased in tumors. CD5(+) B cells responded to IL-6 in the absence of IL-6Rα. IL-6 directly bound to CD5, leading to activation of the transcription factor STAT3 via gp130 and its downstream kinase JAK2. STAT3 upregulated CD5 expression, thereby forming a feed-forward loop in the B cells. In mouse tumor models, CD5(+) but not CD5(-) B cells promoted tumor growth. CD5(+) B cells also showed activation of STAT3 in multiple types of human tumor tissues. Thus, our findings demonstrate a critical role of CD5(+) B cells in promoting cancer.

Cost-effectiveness of polatuzumab vedotin combined with chemoimmunotherapy in untreated diffuse large B-cell lymphoma.

In patients with treatment-naive diffuse large B-cell lymphoma (DLBCL), the POLARIX study (A Study Comparing the Efficacy and Safety of Polatuzumab Vedotin With Rituximab-Cyclophosphamide, Doxorubicin, and Prednisone [R-CHP] Versus Rituximab-Cyclophosphamide, Doxorubicin, Vincristine, and Prednisone [R-CHOP] in Participants With Diffuse Large B-Cell Lymphoma) reported a 6.5% improvement in the 2-year progression-free survival (PFS), with no difference in overall survival (OS) or safety using polatuzumab vedotin, rituximab, cyclophosphamide, doxorubicin, and prednisone (pola-R-CHP) compared with standard rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). We evaluated the cost-effectiveness of pola-R-CHP for DLBCL. We modeled a hypothetical cohort of US adults (mean age, 65 years) with treatment-naive DLBCL by developing a Markov model (lifetime horizon) to model the cost-effectiveness of pola-R-CHP and R-CHOP using a range of plausible long-term outcomes. Progression rates and OS were estimated from POLARIX. Outcome measures were reported in incremental cost-effectiveness ratios, with a willingness-to-pay (WTP) threshold of $150 000 per quality-adjusted life-year (QALY). Assuming a 5-year PFS of 69.6% with pola-R-CHP and 62.7% with R-CHOP, pola-R-CHP was cost-effective at a WTP of $150 000 (incremental cost-effectiveness ratio, $84 308/QALY). pola-R-CHP was no longer cost-effective if its 5-year PFS was 66.1% or lower. One-way sensitivity analysis revealed that pola-R-CHP is cost-effective up to a cost of $276 312 at a WTP of $150 000. pola-R-CHP was the cost-effective strategy in 56.6% of the 10 000 Monte Carlo iterations at a WTP of $150 000. If the absolute benefit in PFS is maintained over time, pola-R-CHP is cost-effective compared with R-CHOP at a WTP of $150 000/QALY. However, its cost-effectiveness is highly dependent on its long-term outcomes and costs of chimeric antigen receptor T-cell therapy. Routine usage of pola-R-CHP would add significantly to health care expenditures. Price reductions or identification of subgroups that have maximal benefit would improve cost-effectiveness.

Response-adapted anti-PD-1-based salvage therapy for Hodgkin lymphoma with nivolumab alone or in combination with ICE.

This phase 2 trial evaluated PET-adapted nivolumab alone or in combination with ifosfamide, carboplatin, and etoposide (NICE) as first salvage therapy and bridge to autologous hematopoietic cell transplantation (AHCT) in relapsed/refractory (RR) classical Hodgkin lymphoma (cHL). Patients with RR cHL received 240 mg nivolumab every 2 weeks for up to 6 cycles (C). Patients in complete response (CR) after C6 proceeded to AHCT, whereas patients with progressive disease at any point or not in CR after C6 received NICE for 2 cycles. The primary endpoint was CR rate per the 2014 Lugano classification at completion of protocol therapy. Forty-three patients were evaluable for toxicity; 42 were evaluable for response. Thirty-four patients received nivolumab alone, and 9 patients received nivolumab+NICE. No unexpected toxicities were observed after nivolumab or NICE. After nivolumab, the overall response rate (ORR) was 81%, and the CR rate was 71%. Among 9 patients who received NICE, all responded, with 8 (89%) achieving CR. At the end of protocol therapy, the ORR and CR rates were 93% and 91%. Thirty-three patients were bridged directly to AHCT, including 26 after Nivo alone. The 2-year progression-free survival (PFS) and overall survival in all treated patients (n = 43) were 72% and 95%, respectively. Among 33 patients who bridged directly to AHCT, the 2-year PFS was 94% (95% CI: 78-98). PET-adapted sequential salvage therapy with nivolumab/nivolumab+NICE was well tolerated and effective, resulting in a high CR rate and bridging most patients to AHCT without chemotherapy. This trial was registered at www.clinicaltrials.gov #NCT03016871.

Cost-effectiveness of second-line axicabtagene ciloleucel in relapsed refractory diffuse large B-cell lymphoma.

The ZUMA-7 (Efficacy of Axicabtagene Ciloleucel Compared to Standard of Care Therapy in Subjects With Relapsed/Refractory Diffuse Large B Cell Lymphoma) study showed that axicabtagene ciloleucel (axi-cel) improved event-free survival (EFS) compared with standard of care (SOC) salvage chemoimmunotherapy followed by autologous stem cell transplant in primary refractory/early relapsed diffuse large B-cell lymphoma (DLBCL); this led to its recent US Food and Drug Administration approval in this setting. We modeled a hypothetical cohort of US adults (mean age, 65 years) with primary refractory/early relapsed DLBCL by developing a Markov model (lifetime horizon) to model the cost-effectiveness of second-line axi-cel compared with SOC using a range of plausible long-term outcomes. EFS and OS were estimated from ZUMA-7. Outcome measures were reported in incremental cost-effectiveness ratios, with a willingness-to-pay (WTP) threshold of $150 000 per quality-adjusted life-year (QALY). Assuming a 5-year EFS of 35% with second-line axi-cel and 10% with SOC, axi-cel was cost-effective at a WTP of $150 000 per QALY ($93 547 per QALY). axi-cel was no longer cost-effective if its 5-year EFS was ≤26.4% or if it cost more than $972 061 at a WTP of $150 000. Second-line axi-cel was the cost-effective strategy in 73% of the 10 000 Monte Carlo iterations at a WTP of $150 000. If the absolute benefit in EFS is maintained over time, second-line axi-cel for aggressive relapsed/refractory DLBCL is cost-effective compared with SOC at a WTP of $150 000 per QALY. However, its cost-effectiveness is highly dependent on long-term outcomes. Routine use of second-line chimeric antigen receptor T-cell therapy would add significantly to health care expenditures in the United States (more than $1 billion each year), even when used in a high-risk subpopulation. Further reductions in the cost of chimeric antigen receptor T-cell therapy are needed to be affordable in many regions of the world.

A randomized phase 2 trial of idiotype vaccination and adoptive autologous T-cell transfer in patients with multiple myeloma.

We hypothesized that combining adoptively transferred autologous T cells with a cancer vaccine strategy would enhance therapeutic efficacy by adding antimyeloma idiotype (Id)-keyhole limpet hemocyanin (KLH) vaccine to vaccine-specific costimulated T cells. In this randomized phase 2 trial, patients received either control (KLH only) or Id-KLH vaccine, autologous transplantation, vaccine-specific costimulated T cells expanded ex vivo, and 2 booster doses of assigned vaccine. In 36 patients (KLH, n = 20; Id-KLH, n = 16), no dose-limiting toxicity was seen. At last evaluation, 6 (30%) and 8 patients (50%) had achieved complete remission in KLH-only and Id-KLH arms, respectively (P = .22), and no difference in 3-year progression-free survival was observed (59% and 56%, respectively; P = .32). In a 594 Nanostring nCounter gene panel analyzed for immune reconstitution (IR), compared with patients receiving KLH only, there was a greater change in IR genes in T cells in those receiving Id-KLH relative to baseline. Specifically, upregulation of genes associated with activation, effector function induction, and memory CD8+ T-cell generation after Id-KLH but not after KLH control vaccination was observed. Similarly, in responding patients across both arms, upregulation of genes associated with T-cell activation was seen. At baseline, all patients had greater expression of CD8+ T-cell exhaustion markers. These changes were associated with functional Id-specific immune responses in a subset of patients receiving Id-KLH. In conclusion, in this combination immunotherapy approach, we observed significantly more robust IR in CD4+ and CD8+ T cells in the Id-KLH arm, supporting further investigation of vaccine and adoptive immunotherapy strategies. This trial was registered at www.clinicaltrials.gov as #NCT01426828.

Results from a phase I trial of pembrolizumab plus vorinostat in relapsed/refractory B-cell non-Hodgkin lymphoma.

Outcomes after programmed death-1 (PD-1) blockade in B-cell lymphomas are disappointing with few durable responses. Histone deacetylase inhibitors exhibit favorable immunomodulatory effects and demonstrate synergistic anti-tumor immune responses with anti-PD-1 therapy in preclinical models. We, therefore, developed a phase I study to evaluate the safety and preliminary efficacy of pembrolizumab with vorinostat in relapsed/refractory B-cell lymphomas. Patients were treated in a dose-escalation cohort using a Rolling 6 design followed by an expansion cohort at the recommended phase II dose (R2PD). Fifty-two patients were enrolled (32 Hodgkin and 20 non-Hodgkin lymphoma [NHL]). Here, we report safety data from the dose escalation cohort, and the toxicity and efficacy within NHL patients. Vorinostat was administered twice daily on days 1-5 and 8-12 (dose-level [DL]1: 100 mg; DL2: 200 mg) and pembrolizumab (200 mg) was administered on day 1 of each 3-week cycle. Of six patients treated at DL1, one had a dose-limiting toxicity (DLT) (Stevens-Johnson syndrome [SJS]), and one of six had a DLT at DL2 (thromboembolism); therefore, DL2 was the RP2D. The patient developing SJS was treated with corticosteroids, infliximab, and cyclosporine but ultimately died of invasive fungal infection from the extensive immunosuppression used to treat the SJS. The most common adverse events were hypertension, diarrhea, and cytopenias. Of 20 NHL patients, nine had follicular lymphoma (FL) and 11 had diffuse large B-cell lymphoma (DLBCL). Five DLBCL patients had primary mediastinal B-cell lymphoma (PMBL). The complete and overall response rates (CR and ORR) were 11% and 22% for FL and 45% and 55% for all DLBCL. Amongst DLBCL, the CR and ORR was 80% and 80% for PMBL and 17% and 33% for non-PMBL. In conclusion, pembrolizumab with vorinostat was tolerable and produced responses in relapsed/refractory B-cell NHL, with particularly notable efficacy in PMBL (clinicaltrials gov. Identifier: NCT03150329).

Targeted In Vivo Delivery of NF-κB Decoy Inhibitor Augments Sensitivity of B Cell Lymphoma to Therapy.

Despite recent advances, non-Hodgkin's B cell lymphoma patients often relapse or remain refractory to therapy. Therapeutic resistance is often associated with survival signaling via nuclear factor κB (NF-κB) transcription factor, an attractive but undruggable molecular target. In this study, we describe a bipartite inhibitor comprising a NF-κB-specific decoy DNA tethered to a CpG oligodeoxynucleotide (ODN) targeting Toll-like receptor-9-expressing B cell lymphoma cells. The Bc-NFκBdODN showed efficient uptake by human diffuse large B cell (U2932, OCI-Ly3), Burkitt (RaJi), and mantle cell (Jeko1) lymphomas, respectively. We confirmed that Bc-NFκBdODN inhibited NF-κB nuclear translocation and DNA binding, resulting in CCND2 and MYC downregulation. Bc-NFκBdODN enhanced radiosensitivity of lymphoma cells in vitro. In xenotransplanted human lymphoma, local injections of Bc-NFκBdODN reduced NF-κB activity in whole tumors. When combined with a local 3-Gy dose of radiation, Bc-NFκBdODN effectively arrested OCI-Ly3 lymphoma progression. In immunocompetent mice, intratumoral injections of Bc-NFκBdODN suppressed growth of directly treated and distant A20 lymphomas, as a result of systemic CD8 T cell-dependent immune responses. Finally, systemic administration of Bc-NFκBdODN to mice bearing disseminated A20 lymphoma induced complete regression and extended survival of most of the treated mice. Our results underscore clinical relevance of this strategy as monotherapy and in support of radiation therapy to benefit patients with resistant or relapsed B cell lymphoma.

Regulation of SOX11 expression through CCND1 and STAT3 in mantle cell lymphoma.

The neural transcription factor SOX11 is usually highly expressed in typical mantle cell lymphoma (MCL), but it is absent in the more indolent form of MCL. Despite being an important diagnostic marker for this hard-to-treat malignancy, the mechanisms of aberrant SOX11 expression are largely unknown. Herein, we describe 2 modes of SOX11 regulation by the cell-cycle regulator cyclin D1 (CCND1) and the signal transducer and activator of transcription 3 (STAT3). We found that ectopic expression of CCND1 in multiple human MCL cell lines resulted in increased SOX11 transcription, which correlated with increased acetylated histones H3K9 and H3K14 (H3K9/14Ac). Increased H3K9/14Ac and SOX11 expression was also observed after histone deacetylase 1 (HDAC1) or HDAC2 was depleted by RNA interference or inhibited by the HDAC inhibitor vorinostat. Mechanistically, we showed that CCND1 interacted with and sequestered HDAC1 and HDAC2 from the SOX11 locus, leading to SOX11 upregulation. Interestingly, our data revealed a potential inverse relationship between phosphorylated Y705 STAT3 and SOX11 expression in MCL cell lines, primary tumors, and patient-derived xenografts. Functionally, inactivation of STAT3 by inhibiting the upstream Janus kinase (JAK) 1 or JAK2 or by STAT3 knockdown was found to increase SOX11 expression, whereas interleukin-21 (IL-21)-induced STAT3 activation or overexpression of the constitutively active form of STAT3 decreased SOX11 expression. In addition, targeting SOX11 directly by RNA interference or indirectly by IL-21 treatment induced toxicity in SOX11+ MCL cells. Collectively, we demonstrate the involvement of CCND1 and STAT3 in the regulation of SOX11 expression, providing new insights and therapeutic implications in MCL.

Antitumor efficacy of BAFF-R targeting CAR T cells manufactured under clinic-ready conditions.

B-cell malignancies can potentially be cured by CD19 chimeric antigen receptor (CAR) T-cell therapy. Although clinical response rates can be up to 93% in acute lymphoblastic leukemia, treatment-related antigen loss and lack of therapeutic persistence contribute to disease relapse. These shortcomings of current CAR T-cell therapy indicate the need for biologically relevant target selection and for improving the efficacy and persistence of the CAR T cells, which we have addressed by developing a novel B-cell activating factor receptor (BAFF-R) CAR T-cell therapy with improved therapeutic persistence. BAFF-R is a B-cell survival receptor and highly expressed in B-cell malignancies. We developed a prototype CAR T cell that efficiently and specifically eliminated BAFF-R expressing human B-cell tumors in several xenogeneic mouse models, including models of CD19 antigen loss. We proceeded with translational development and validation of BAFF-R CAR T cells produced under current good manufacturing practices (cGMP). cGMP-grade BAFF-R CAR T cells underwent in vitro and in vivo validation in established models to confirm that the potency and efficacy of our original research modeling was replicated. Food and Drug Administration required release testing was performed to ensure our BAFF-R CAR T cells meet specifications for new drug products. Completing and exceeding these requirements, the data fully support the initiation of a first-in-human Phase 1 trial for BAFF-R-positive relapsed/refractory (r/r) B-ALL.

Long-term overall- and progression-free survival after pentostatin, cyclophosphamide and rituximab therapy for indolent non-Hodgkin lymphoma.

In a prospective phase II trial, pentostatin combined with cyclophosphamide and rituximab (PCR) induced strong responses and was well-tolerated in previously untreated patients with advanced-stage, indolent non-Hodgkin lymphoma (iNHL). After a median patient follow-up of more than 108 months, we performed an intent-to-treat analysis of our 83 participants. Progression-free survival (PFS) rates at 108 months for follicular lymphoma (FL), marginal zone lymphoma (MZL) and small lymphocytic lymphoma (SLL) were 71%, 67% and 15%, respectively, and were affected by clinicopathological characteristics. Ten-year PFS rates for those with beta-2-microglobulin levels <2·2 and ≥2·2 mg/l prior to treatment were 71% and 21%, respectively. Patients without bone marrow involvement had 10-year PFS rates of 72% vs. 29% for those with involvement. At time of analysis, the median overall survival (OS) had not been reached. The OS rate was 64% at 10 years and differed significantly based on histology: 94% for FL, 66% for MZL and 39% for SLL. Long-term toxicities included 18 (21·7%) patients with second malignancies and 2 (2·4%) who developed myelodysplastic syndrome after receiving additional lines of chemotherapy. Our 10-year follow-up analysis confirms that PCR is an effective, robust and tolerable treatment regimen for patients with iNHL.

B Cell Lymphoma Immunotherapy Using TLR9-Targeted Oligonucleotide STAT3 Inhibitors.

Growing evidence links the aggressiveness of non-Hodgkin's lymphoma, especially the activated B cell-like type diffuse large B cell lymphomas (ABC-DLBCLs) to Toll-like receptor 9 (TLR9)/MyD88 and STAT3 transcription factor signaling. Here, we describe a dual-function molecule consisting of a clinically relevant TLR9 agonist (CpG7909) and a STAT3 inhibitor in the form of a high-affinity decoy oligodeoxynucleotide (dODN). The CpG-STAT3dODN blocked STAT3 DNA binding and activity, thus reducing expression of downstream target genes, such as MYC and BCL2L1, in human and mouse lymphoma cells. We further demonstrated that injections (i.v.) of CpG-STAT3dODN inhibited growth of human OCI-Ly3 lymphoma in immunodeficient mice. Moreover, systemic CpG-STAT3dODN administration induced complete regression of the syngeneic A20 lymphoma, resulting in long-term survival of immunocompetent mice. Both TLR9 stimulation and concurrent STAT3 inhibition were critical for immune-mediated therapeutic effects, since neither CpG7909 alone nor CpG7909 co-injected with unconjugated STAT3dODN extended mouse survival. The CpG-STAT3dODN induced expression of genes critical to antigen-processing/presentation and Th1 cell activation while suppressing survival signaling. These effects resulted in the generation of lymphoma cell-specific CD8/CD4-dependent T cell immunity protecting mice from tumor rechallenge. Our results suggest that CpG-STAT3dODN as a systemic/local monotherapy or in combination with PD1 blockade can provide an opportunity for treating patients with B cell NHL.

Outcomes after Allogeneic Stem Cell Transplantation in Patients with Double-Hit and Double-Expressor Lymphoma.

Double-hit lymphomas (DHLs) and double-expressor lymphomas (DELs) are associated with resistance to frontline and salvage immunochemotherapy, as well as autologous stem cell transplantation (SCT). We hypothesized that allogeneic SCT (alloSCT) could overcome the chemoresistance associated with DEL/DHL. We retrospectively studied the impact of DEL/DHL status in a multicenter cohort of patients who underwent alloSCT for relapsed/refractory (rel/ref) aggressive B cell non-Hodgkin lymphoma (B-NHL). Seventy-eight patients transplanted at 3 centers in whom tumor tissue was available for immunohistochemistry and fluorescence in situ hybridization were enrolled; 47% had DEL and 13% had DHL. There were no significant differences in 4-year progression-free (PFS) or overall survival (OS) between patients with DEL compared with patients without DEL (PFS 30% versus 39%, P = .24; OS 31% versus 49%, P = .17) or between patients with DHL compared with patients without DHL (PFS 40% versus 34%, P = .62; OS 50% versus 38%, P = .46). The lack of association between DEL or DHL and outcome was confirmed in multivariable models, although inadequate sample size may have limited our ability to detect significant differences. In our cohort alloSCT produced durable remissions in patients with rel/ref aggressive B-NHL irrespective of DEL and DHL status, justifying its consideration in the treatment of patients with rel/ref DEL/DHL.

Phase 2 trial of bortezomib in combination with rituximab plus hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone alternating with bortezomib, rituximab, methotrexate, and cytarabine for untreated mantle cell lymphoma.

BACKGROUND: Although the outcomes of patients with mantle cell lymphoma (MCL) have improved, there is still no cure. Bortezomib has a 33% response rate in relapsed/refractory MCL and has shown additive and/or synergistic effects in preclinical trials with known effective agents. METHODS: This is a report of a prospective phase 2 trial of bortezomib added to rituximab plus hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone (BzR-hyperCVAD)/rituximab, high-dose methotrexate, and high-dose cytarabine (BzR-MA) for 95 patients with newly diagnosed MCL. RESULTS: The overall and complete response rates were 100% and 82%, respectively. Hematologic toxicity was high but expected and did not lead to an increased incidence of neutropenic fever or dose reductions in comparison with a similar reported regimen without bortezomib. After a median follow-up of 44 months, the median overall survival had not been reached, and the time to treatment failure (TTF) was 55 months, which is not different from that of historical controls. CONCLUSIONS: BzR-hyperCVAD/BzR-MA at the dose and schedule studied produced high rates of response and a TTF similar to that of historical reports without bortezomib. Cancer 2018;124:2561-9. © 2018 American Cancer Society.

Targeting myeloid-derived suppressor cells for cancer immunotherapy.

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of immature myeloid cells with an immune suppressive phenotype. They represent a critical component of the immune suppressive niche described in cancer, where they support immune escape and tumor progression through direct effects on both the innate and adaptive immune responses, largely by contributing to maintenance of a high oxidative stress environment. The number of MDSCs positively correlates with protumoral activity, and often diminishes the effectiveness of immunotherapies, which is particularly problematic with the emergence of personalized medicine. Approaches targeting MDSCs showed promising results in preclinical studies and are under active investigation in clinical trials in combination with various immune checkpoint inhibitors. In this review, we discuss MDSC targets and therapeutic approaches targeting MDSC that have the aim of enhancing the existing tumor therapies.

Phase I study of an active immunotherapy for asymptomatic phase Lymphoplasmacytic lymphoma with DNA vaccines encoding antigen-chemokine fusion: study protocol.

BACKGROUND: There is now a renewed interest in cancer vaccines. Patients responding to immune checkpoint blockade usually bear tumors that are heavily infiltrated by T cells and express a high load of neoantigens, indicating that the immune system is involved in the therapeutic effect of these agents; this finding strongly supports the use of cancer vaccine strategies. Lymphoplasmacytic lymphoma (LPL) is a low grade, incurable disease featuring an abnormal proliferation of Immunoglobulin (Ig)-producing malignant cells. Asymptomatic patients are currently managed by a "watchful waiting" approach, as available therapies provide no survival advantage if started before symptoms develop. Idiotypic determinants of a lymphoma surface Ig, formed by the interaction of the variable regions of heavy and light chains, can be used as a tumor-specific marker and effective vaccination using idiotypes was demonstrated in a positive controlled phase III trial. METHODS: These variable region genes can be cloned and used as a DNA vaccine, a delivery system holding tremendous potential for streamlining vaccine production. To increase vaccination potency, we are targeting antigen-presenting cells (APCs) by fusing the antigen with a sequence encoding a chemokine (MIP-3α), which binds an endocytic surface receptor on APCs. Asymptomatic phase LPL is an excellent model to test our vaccine since patients have not received chemotherapeutics that interfere with innate immune function and have low tumor burden. We are evaluating the safety of this next-generation DNA vaccine in a first-in-human clinical trial currently enrolling asymptomatic LPL patients. To elucidate the mode of action of this vaccine, we will assess its ability to generate tumor-specific immune responses and examine changes in the immune profile of both the peripheral blood and bone marrow. DISCUSSION: This vaccine could shift the current paradigm of clinical management for patients with asymptomatic LPL and inform development of other personalized approaches. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT01209871; registered on September 24, 2010.

Long-Term Results of High-Dose Therapy and Autologous Stem Cell Transplantation for Mantle Cell Lymphoma: Effectiveness of Maintenance Rituximab.

High-dose therapy followed by autologous stem cell transplantation (ASCT) can improve outcomes for mantle cell lymphoma (MCL) but is associated with a high incidence of relapse. A retrospective study of 191 MCL patients who underwent ASCT at City of Hope was performed to examine prognostic factors for outcomes after ASCT. For all patients the 5-year overall survival (OS) was 71% (95% confidence interval [CI], 63% to 77%) and progression-free survival (PFS) was 53% (95% CI, 45% to 60%). The 5-year cumulative incidence of relapse was 41% (95% CI, 34% to 48%) with a continuous pattern of relapse events occurring at a median of 2.1 years (range, .2 to 13.4) after ASCT. In multivariate analysis, post-transplant maintenance rituximab was the factor most significantly associated with both OS (relative risk [RR], .17; 95% CI, .07 to .38) and PFS (RR, .25; 95% CI, .14 to .44). For the subset of patients who had positron emission tomography (PET) data available and were in a PET-negative first complete remission at ASCT (n = 105), maintenance rituximab was significantly associated with superior OS (RR, .17; 95% CI, .05 to .59) and PFS (RR, .20; 95% CI, .09 to .43). These results support a benefit with maintenance rituximab for all MCL patients treated with ASCT.

Rituximab plus hyper-CVAD alternating with MTX/Ara-C in patients with newly diagnosed mantle cell lymphoma: 15-year follow-up of a phase II study from the MD Anderson Cancer Center.

Intensive chemotherapy regimens containing cytarabine have substantially improved remission durability and overall survival in younger adults with mantle cell lymphoma (MCL). However, there have been no long-term follow-up results for patients treated with these regimens. We present long-term survival outcomes from a pivotal phase II trial of rituximab, hyper-fractionated cyclophosphamide, vincristine, doxorubicin and dexamethasone alternating with methotrexate and cytarabine (R-HCVAD/MA). At 15 years of follow-up (median: 13·4 years), the median failure-free survival (FFS) and overall survival (OS) for all patients was 4·8 years and 10·7 years, respectively. The FFS seems to have plateaued after 10 years, with an estimated 15-year FFS of 30% in younger patients (≤65 years). Patients who achieved complete response (CR) after 2 cycles had a favourable median FFS of 8·8 years. Six patients developed myelodysplastic syndrome/acute myeloid leukaemia (MDS/AML) whilst in first CR. The 10-year cumulative incidence of MDS/AML of patients in first remission was 6·2% (95% confidence interval: 2·5-12·2%). In patients with newly diagnosed MCL, R-HCVAD/MA showed sustained efficacy, with a median OS exceeding 10 years in all patients and freedom from disease recurrence of nearly 15 years in almost one-third of the younger patients (≤65 years).

Osteoblastic niche supports the growth of quiescent multiple myeloma cells.

The heterogeneity of multiple myeloma (MM) contributes to variable responses to therapy. In this study, we aim to correlate the heterogeneity of MM to the presence of quiescent cells using the PKH26 dye. We tracked the rare quiescent cells in different niches of the bone marrow by allowing the cells to cycle in vivo. Surprisingly, quiescent PKH(+) MM cells prefer to reside within the osteoblastic niches of the bone marrow (PKH(+)/OS) rather than the vascular (VS) niches or the spleen. These cells (PKH(+)/OS) displayed enhanced stemlike properties by forming colonies in semisolid medium. PKH(+) cells were highly tumorigenic compared with PKH(-) cells and were resistant to a variety of drugs. However, the levels of drug resistance were somewhat similar regardless of where the PKH(+) cells were isolated. Our data indicate that osteoblastic niches support the growth of quiescent PKH(+) cells and allow them to have stemlike functions.