Phase 1/2 study of intratumoral G100 (TLR4 agonist) with or without pembrolizumab in follicular lymphoma.

Intratumoral injection of G100, a toll-like receptor 4 (TLR4) agonist, was shown pre-clinically to stimulate anti-tumor immune responses and tumor regression. This open-label, multicenter, phase 1/2 trial evaluated the safety, tolerability, and preliminary efficacy of intratumoral G100 injections following localized low-dose radiation in patients with follicular lymphoma (ClinicalTrials.gov #NCT02501473). The study was comprised of a G100 dose escalation (5 or 10 µg/dose, or 20 µg/dose for large tumors); a randomized component comparing G100 to G100 plus pembrolizumab; and G100 20 µg/dose expansion. Adverse events grade ≥3 were uncommon in patients treated with G100, and no unexpected toxicities were observed when combined with pembrolizumab. G100 20 µg (n = 18) resulted in an overall response rate of 33.3% and abscopal tumor regression in 72.2% of patients. This early-phase study provides a foundation for combining an intratumoral TLR4 agonist with agents to produce immune-mediated responses in follicular lymphoma with limited added toxicity.

Primary cutaneous Epstein-Barr virus-positive diffuse large B-cell lymphoma (DLBCL) in a patient taking fingolimod.

A 55-year-old man with relapsing-remitting multiple sclerosis on fingolimod presented to the dermatology clinic with skin lesions on the left temple and cheek. Histopathology showed a diffuse infiltrate of enlarged, atypical lymphocytes throughout the dermis with an overlying grenz zone and a subpopulation of scattered smaller lymphocytes and plasma cells. Epstein-Barr virus-encoded RNA in situ hybridization stain was positive. Based on the morphologic and immunophenotypic findings, a diagnosis of EBV-positive diffuse large B-cell lymphoma was made. This case aims to raise awareness for the dermatologist that patients on fingolimod may be at increased risk of lymphoproliferative disorders.

Cyclin-Dependent Kinase-9 Is a Therapeutic Target in MYC-Expressing Diffuse Large B-Cell Lymphoma.

Deregulation of the MYC transcription factor is a key driver in lymphomagenesis. MYC induces global changes in gene expression that contribute to cell growth, proliferation, and oncogenesis by stimulating the activity of RNA polymerases. A key feature in its ability to stimulate RNA Pol II activity is recruitment of pTEFb, an elongation factor whose catalytic core comprises CDK9/cyclin T complexes. Hence, MYC expression and function may be susceptible to CDK9 inhibition. We conducted a pre-clinical assessment of AZ5576, a selective CDK9 inhibitor, in diffuse large B-cell lymphoma (DLBCL). The in vitro and in vivo effects of AZ5576 on apoptosis, cell cycle, Mcl-1, and MYC expression were assessed by flow cytometry, immunoblotting, qPCR and RNA-Seq. We demonstrate that, in addition to depleting Mcl-1, targeting CDK9 disrupts MYC oncogenic function. Treatment with AZ5576 inhibited growth of DLBCL cell lines in vitro and in vivo, independent of cell-of-origin. CDK9 inhibition downregulated Mcl-1 and MYC mRNA transcript and protein in a dose-dependent manner. MYC-expressing cell lines demonstrated enhanced susceptibility to AZ5576. CDK9 inhibition promoted turnover of MYC protein, and decreased MYC phosphorylation at the stabilizing Ser62 residue and downregulated MYC transcriptional targets in DLBCL cells, a finding confirmed in a functional reporter assay, suggesting that CDK9 may govern MYC protein turnover, thus regulating its expression through multiple mechanisms. Our data suggest that targeting CDK9 is poised to disrupt MYC oncogenic activity in DLBCL and provide rationale for clinical development of selective CDK9 inhibitors.

Colorectal Lymphoma: A Review.

Non-Hodgkin lymphoma (NHL) that primarily involves the colon is rare and should be distinguished from the more common systemic nodal lymphoma. It has unique clinical expectations and management consideration. Different histologic subtypes of NHL involve the colon, which varies in the clinical behavior and likelihood of obtaining durable remissions with treatment. This article will review the current understanding of the different histologic subtypes of primary colorectal lymphoma and propose management algorithms.

Outcomes of DA-EPOCH-R induction plus autologous transplant consolidation for double hit lymphoma.

High-grade B cell lymphoma with MYC and BCL2 rearrangements (double hit) has a poor prognosis with standard R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone). We report here a treatment algorithm of DA-EPOCH-R (dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, rituximab) followed by BEAM (carmustine, etoposide, cytarabine, melphalan) autologous transplant in 36 cases of previously untreated double hit lymphoma (DHL) from 2010 to 2015. A high risk International Prognostic Index (IPI) was present in 42% of cases. At median follow-up of 38 months, the 2-year progression free survival (PFS) and overall survival (OS) were 69% (95% CI 54-84%) and 71% (95% CI 56-86%). Eight cases were refractory to induction with 1-year OS 20%, and no factors were predictive for primary refractory disease. Of 28 responders, 17 proceeded to transplant while 11 were observed, primarily due to age and co-morbidities. By 24-week landmark analysis after diagnosis, the 2-year PFS and OS were both 94% (95% CI 83-100%) vs 79% (95% CI 52-100%) for transplant vs observation (p = .59 for both PFS and OS). There was no significant benefit to consolidative transplant in our series, and primary refractory DHL needs novel approaches.

Targeting the programmed cell death 1 pathway in Hodgkin lymphoma: the place of nivolumab.

Nivolumab is a humanized immunoglobulin gamma-4 kappa anti-programmed cell death 1 monoclonal antibody that is currently approved in the treatment of several solid tumors and recently gained accelerated approval in classical Hodgkin lymphoma (cHL) that has relapsed or progressed following autologous hematopoietic stem-cell transplantation and post-transplantation brentuximab vedotin. The purpose of this article is to review the immunophysiologic basis, clinical efficacy, and toxicity of nivolumab in the treatment of cHL. In addition, we will review ongoing clinical trials and potential future directions of checkpoint inhibition in the treatment of cHL.

Adjuvant IL-15 does not enhance the efficacy of tumor cell lysate-pulsed dendritic cell vaccines for active immunotherapy of T cell lymphoma.

There has been a recent interest in using IL-15 to enhance antitumor activity in several models because of its ability to stimulate CD8+ T cell expansion, inhibit apoptosis and promote memory T cell survival and maintenance. Previously, we reported that C6VL tumor lysate-pulsed dendritic cell vaccines significantly enhanced the survival of tumor-bearing mice by stimulating a potent tumor-specific CD8+ T cell response. In this study, we determined whether IL-15 used as immunologic adjuvant would augment vaccine-primed CD8+ T cell immunity against C6VL and further improve the survival of tumor-bearing mice. We report that IL-15 given after C6VL lysate-pulsed dendritic cell vaccines stimulated local and systemic expansion of NK, NKT and CD8+ CD44hi T cells. IL-15 did not, however, augment innate or cellular responses against the tumor. T cells from mice infused with IL-15 following vaccination did not secrete increased levels of tumor-specific TNF-alpha or IFN-gamma or have enhanced C6VL-specific CTL activity compared to T cells from recipients of the vaccine alone. Lastly, IL-15 did not enhance the survival of tumor-bearing vaccinated mice. Thus, while activated- and memory-phenotype CD8+ T cells were dramatically expanded by IL-15 infusion, vaccine-primed CD8+ T cell specific for C6VL were not significantly expanded. This is the first account of using IL-15 as an adjuvant in a therapeutic model of active immunotherapy where there was not a preexisting pool of tumor-specific CD8+ T cells. Our results contrast the recent studies where IL-15 was successfully used to augment tumor-reactivity of adoptively transferred transgenic CD8+ T cells. This suggests that the adjuvant potential of IL-15 may be greatest in settings where it can augment the number and activity of preexisting tumor-specific CD8+ T cells.

Galloping ophthalmoplegia and numb chin in Burkitt lymphoma.

A 57-year-old man developed complete bilateral ophthalmoplegia over a period of 10 days, together with bilateral facial pain and numbness of the chin. He had no other clinical manifestations. Findings on brain magnetic resonance imaging and spinal fluid formula from the first lumbar puncture were normal, but cerebrospinal fluid flow cytometry disclosed a kappa restriction monoclonal B-cell population, indicating malignant lymphoma. Computed tomography of the chest, abdomen, and pelvis then revealed multiple enlarged lymph nodes. Biopsy of an inguinal node showed findings consistent with Burkitt lymphoma. Within six weeks, intravenous and intrathecal chemotherapy resolved all neurologic findings except a partial right-side sixth nerve palsy and mild chin numbness. Eighteen months after disease onset, the patient remained in remission. Meningeal spread of Burkitt lymphoma is not commonly a presenting feature in immunocompetent adults. Chin numbness, a characteristic feature caused by infiltration of the mental nerve, should facilitate earlier recognition, which may be life saving.

TCR vaccines against a murine T cell lymphoma: a primary role for antibodies of the IgG2c class in tumor protection.

Tumor-associated proteins can act as effective immunotherapeutic targets. Immunization with tumor TCR protein conjugated to the immunogenic protein keyhole limpet hemocyanin (KLH) protects mice from tumor challenge with the murine T cell lymphoma C6VL. The immune mechanisms responsible for this tumor protection are of interest for designing more effective vaccine strategies. Previous studies using depletion experiments had suggested a CD8-mediated component of protection induced by TCR-KLH vaccines. In this study we used CD8alpha knockout, micro MT, and FcgammaR knockout mice to investigate the relative roles of CD8+ T cells and Ab in protective immunity induced by TCR-KLH immunization. We found that CD8+ T cells are not required for tumor protection, although they may contribute to protection. Vaccine-induced Abs are sufficient to mediate protection against this murine T cell lymphoma through an FcR-dependent mechanism. This was confirmed with Ab transfers, which protect challenged mice. Additionally, recombinase-activating gene 1(-/-) splenocytes can mediate Ab-dependent cellular cytotoxicity against this tumor in the presence of bound anti-TCR Abs. IFN-gamma knockout mice demonstrated a requirement for IFN-gamma, probably via generation of IgG2c Abs, in vaccine-induced tumor protection. IFN-gamma knockout mice were not protected by immunization and had a severe impairment in IgG2c Ab production in response to immunization. Although mock-depleted anti-TCR Abs could transfer tumor protection, IgG2c-deficient anti-TCR Abs were unable to transfer tumor protection to wild-type mice. These results suggest that TCR-KLH vaccine-induced tumor protection in the C6VL system is primarily attributable to the induction of IgG2c Abs and humoral immunity.

Tumor cell lysate-pulsed dendritic cells are more effective than TCR Id protein vaccines for active immunotherapy of T cell lymphoma.

TCR Id protein conjugated to keyhole limpet hemocyanin (KLH) (TCR Id:KLH) and injected with a chemical adjuvant (QS-21) induces a protective, Id-specific immune response against the murine T cell lymphoma, C6VL. However, Id-based immunotherapy of C6VL has not demonstrated therapeutic efficacy in tumor-bearing mice. We report here that C6VL lysate-pulsed dendritic cells (C6VL-DC) vaccines display enhanced efficacy in both the prevention and the therapy of T cell lymphoma compared with TCR Id:KLH with QS-21 vaccines. C6VL-DC vaccines stimulated potent tumor-specific immunity that protected mice against lethal challenge with C6VL and significantly enhanced the survival of tumor-bearing mice. Tumor-specific proliferation and secretion of IFN-gamma indicative of a Th1-type immune response were observed upon ex vivo stimulation of vaccine-primed lymph node cells. Adoptive transfer of immune T cell-enriched lymphocytes was sufficient to protect naive recipients from lethal tumor challenge. Furthermore, CD8(+) T cells were absolutely required for tumor protection. Although C6VL-DC and control vaccines stimulated low levels of tumor-specific Ab production in mice, Ab levels did not correlate with the protective ability of the vaccine. Thus, tumor cell lysate-pulsed DC vaccines appear to be an effective approach to generate potent T cell-mediated immune responses against T cell malignancies without requiring identification of tumor-specific Ags or patient-specific Id protein expression.

Idiotype-pulsed dendritic cell vaccination for B-cell lymphoma: clinical and immune responses in 35 patients.

Tumor-specific clonal immunoglobulin expressed by B-cell lymphomas (idiotype [Id]) can serve as a target for active immunotherapy. We have previously described the vaccination of 4 patients with follicular lymphoma using dendritic cells (DCs) pulsed with tumor-derived Id protein and now report on 35 patients treated using this approach. Among 10 initial patients with measurable lymphoma, 8 mounted T-cell proliferative anti-Id responses, and 4 had clinical responses--2 complete responses (CRs) (progression-free [PF] for 44 and 57 months after vaccination), 1 partial response (PR) (PF for 12 months), and 1 molecular response (PF for 75+ months). Subsequently, 25 additional patients were vaccinated after first chemotherapy, and 15 of 23 (65%) who completed the vaccination schedule mounted T-cell or humoral anti-Id responses. Induction of high-titer immunoglobulin G anti-Id antibodies required coupling of Id to the immunogenic carrier protein keyhole limpet hemocyanin (Id-KLH). These antibodies could bind to and induce tyrosine phosphorylation in autologous tumor cells. Among 18 patients with residual tumor at the time of vaccination, 4 (22%) had tumor regression, and 16 of 23 patients (70%) remain without tumor progression at a median of 43 months after chemotherapy. Six patients with disease progression after primary DC vaccination received booster injections of Id-KLH protein, and tumor regression was observed in 3 of them (2 CRs and 1 PR). We conclude that Id-pulsed DC vaccination can induce T-cell and humoral anti-Id immune responses and durable tumor regression. Subsequent boosting with Id-KLH can lead to tumor regression despite apparent resistance to the primary DC vaccine.