Molecular action of lenalidomide in lymphocytes and hematologic malignancies

Emerging immunotherapies in the Hodgkin lymphoma armamentarium

INTRODUCTION

Brentuximab vedotin and PD-1 inhibitors have improved outcomes for classic Hodgkin lymphoma (cHL), but better therapies are needed for patients who relapse after these agents. Based on an improved understanding of cHL biology, there is a robust pipeline of novel therapies in development. In this review, we highlight emerging immunotherapeutic agents and combinations for cHL.

AREAS COVERED

We review clinical trials of novel PD-1/PD-L1 inhibitors beyond FDA-approved agents, checkpoint inhibitors targeting CTLA-4, LAG-3, TIM-3, TIGIT, and CD47/SIRPα, PD-1 inhibitor combinations with immunomodulatory agents and epigenetic modifying therapies, antibody-drug conjugates, bispecific antibodies, and cellular therapies including anti-CD30 CAR-T and allogeneic NK cell therapy. We review the key safety and efficacy data from published phase 1-2 studies and highlight trials in progress, including the first phase 3 trial for PD-1 inhibitor-refractory cHL.

EXPERT OPINION

Many novel immunotherapies hold great promise in cHL. Rational combinations with existing agents and next-generation antibody and CAR-T constructs may improve response rates and durability. Identifying biomarkers of response to these immunotherapies and using more sensitive tools to assess response, such as circulating tumor DNA, may further inform treatment decisions and enable a precision medicine approach in the future.

Safety and activity of lenalidomide in combination with obinutuzumab in patients with relapsed indolent non-Hodgkin lymphoma: a single group, open-label, phase 1/2 trial

Background

Rituximab and lenalidomide is a preferred option for relapsed indolent B cell non-Hodgkin lymphoma. Obinutuzumab may be a superior combination partner with lenalidomide given enhanced antibody dependent cellular cytotoxicity and phagocytosis compared to rituximab. Our aim was to determine the recommended phase 2 dose, safety, and activity of lenalidomide in combination with fixed dose of obinutuzumab in relapsed and refractory indolent B cell non-Hodgkin lymphoma.

Methods

In this single-arm, open-label, phase 1/2 trial, we enrolled patients with relapsed or refractory WHO Grade 1-3A follicular lymphoma, marginal zone lymphoma and small lymphocytic lymphoma and adequate performance status (ECOG 0-2) at the MD Anderson Cancer Center. We excluded patients with evidence of ongoing transformation to aggressive lymphoma. During phase 1, 1000 mg intravenous obinutuzumab was administered with three predefined levels of oral lenalidomide in a 3 + 3 dose escalation design to establish lenalidomide 20 mg as the recommended phase 2 dose. During phase 2, patients received induction therapy with six 28-day cycles of lenalidomide 20 mg with intravenous obinutuzumab 1000 mg. In accordance with our prior experience with lenalidomide plus rituximab, patients who were responding to the combination could receive up to 6 additional cycles (up to 12 cycles in total) of combination therapy. Dosing of obinutuzumab was continued in all responding patients after cycle 6 every 2 months for a total of 30 months from the start of therapy. The decision of number of cycles of combination therapy beyond 6 was at discretion of the investigator and was included to allow individualisation of therapy to maximise response while minimising exposure. The co-primary objectives were to evaluate the safety and overall response, defined as the proportion of patients who achieved a complete or partial response in relapsed and refractory indolent non-Hodgkin lymphoma at the end of induction therapy, according to Cheson and colleagues (2007 criteria). The secondary endpoints were complete response after induction therapy and time to event endpoints including time to progression, progression free survival, and overall survival. Analyses were intent to treat in the efficacy cohort and per-treated in the safety population in all patients who received at least one dose of either investigational agent. This trial is registered with ClinicalTrials.gov, NCT01995669.

Findings

Between June 03, 2014, and 07 March 2019, we completed planned enrolment, and 66 patients started therapy including 9 patients in phase 1 and 57 patients in phase 2. All patients were evaluated for safety and the 60 patients treated at the recommended phase 2 dose of lenalidomide 20 mg were evaluable for activity. Grade 3-4 haematological toxicities included neutropenia 21% (14/66) and thrombocytopenia 11% (7/66) with no cases of febrile neutropenia. Grade 3-4 non-haematological toxicities included lung infection 8% (5/66), fatigue 8% (5/66) and rash 6% (4/66). By Cheson 2007 criteria, 90% (54/60, 95% CI: 79-96) achieved an overall response at the end of induction meeting the prespecified activity endpoint. Complete responses were seen in 33% (20/60, 95% CI: 22-47) at the end of induction. Median progression free survival, time to progression and overall survival have not been reached after median follow-up of 41.7 months. Estimated 4-year progression free survival rates were 55% (95% CI: 42-73), time to progression of 56% (95% CI: 43-74) and overall survival of 84% (95% CI: 74-95).

Interpretation

Our findings suggest that oral lenalidomide with obinutuzumab is safe and highly active in patients with relapsed and refractory indolent B cell non-Hodgkin lymphoma and is associated with prolonged remission duration. The study is limited by the lack of a control arm leading to cross-trial comparisons to evaluate activity. Future randomised trials comparing this regime to rituximab and lenalidomide are warranted.

Funding

Genentech and an MD Anderson Core grant.

Optimizing Treatment for Relapsed/Refractory Classic Hodgkin Lymphoma in the Era of Immunotherapy

Most patients with classic Hodgkin lymphoma (cHL) are cured with combination chemotherapy, but approximately 10-20% will relapse, and another 5-10% will have primary refractory disease. The treatment landscape of relapsed/refractory (R/R) cHL has evolved significantly over the past decade following the approval of brentuximab vedotin (BV), an anti-CD30 antibody-drug conjugate, and the PD-1 inhibitors nivolumab and pembrolizumab. These agents have significantly expanded options for salvage therapy prior to autologous hematopoietic cell transplantation (AHCT), post-transplant maintenance, and treatment of relapse after AHCT, which have led to improved survival in the modern era. In this review, we highlight our approach to the management of R/R cHL in 2023 with a focus on choosing first salvage therapy, post-transplant maintenance, and treatment of relapse after AHCT. We also discuss the management of older adults and transplant-ineligible patients, who require a separate approach. Finally, we review novel immunotherapy approaches in clinical trials, including combinations of PD-1 inhibitors with other immune-activating agents as well as novel antibody-drug conjugates, bispecific antibodies, and cellular immunotherapies. Ongoing studies assessing biomarkers of response to immunotherapy and dynamic biomarkers such as circulating tumor DNA may further inform treatment decisions and enable a more personalized approach in the future.

The effects of dendritic cell-based vaccines in the tumor microenvironment: Impact on myeloid-derived suppressor cells

Dendritic cells (DCs) are a heterogenous population of professional antigen presenting cells whose main role is diminished in a variety of malignancies, including cancer, leading to ineffective immune responses. Those mechanisms are inhibited due to the immunosuppressive conditions found in the tumor microenvironment (TME), where myeloid-derived suppressor cells (MDSCs), a heterogeneous population of immature myeloid cells known to play a key role in tumor immunoevasion by inhibiting T-cell responses, are extremely accumulated. In addition, it has been demonstrated that MDSCs not only suppress DC functions, but also their maturation and development within the myeloid linage. Considering that an increased number of DCs as well as the improvement in their functions boost antitumor immunity, DC-based vaccines were developed two decades ago, and promising results have been obtained throughout these years. Therefore, the remodeling of the TME promoted by DC vaccination has also been explored. Here, we aim to review the effectiveness of different DCs-based vaccines in murine models and cancer patients, either alone or synergistically combined with other treatments, being especially focused on their effect on the MDSC population.

Reshaping the tumor microenvironment: The versatility of immunomodulatory drugs in B-cell neoplasms

Immunomodulatory drugs (IMiDs) such as thalidomide, lenalidomide and pomalidomide are antitumor compounds that have direct tumoricidal activity and indirect effects mediated by multiple types of immune cells in the tumor microenvironment (TME). IMiDs have shown remarkable therapeutic efficacy in a set of B-cell neoplasms including multiple myeloma, B-cell lymphomas and chronic lymphocytic leukemia. More recently, the advent of immunotherapy has revolutionized the treatment of these B-cell neoplasms. However, the success of immunotherapy is restrained by immunosuppressive signals and dysfunctional immune cells in the TME. Due to the pleiotropic immunobiological properties, IMiDs have shown to generate synergetic effects in preclinical models when combined with monoclonal antibodies, immune checkpoint inhibitors or CAR-T cell therapy, some of which were successfully translated to the clinic and lead to improved responses for both first-line and relapsed/refractory settings. Mechanistically, despite cereblon (CRBN), an E3 ubiquitin ligase, is considered as considered as the major molecular target responsible for the antineoplastic activities of IMiDs, the exact mechanisms of action for IMiDs-based TME re-education remain largely unknown. This review presents an overview of IMiDs in regulation of immune cell function and their utilization in potentiating efficacy of immunotherapies across multiple types of B-cell neoplasms.

Current options and future perspectives in the treatment of patients with relapsed/refractory diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) represents the most common subtype of aggressive lymphoma. Depending on individual risk factors, roughly 60–65% of patients can be cured by chemoimmunotherapy with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). However, patients with primary refractory disease or relapse (R/R) after an initial response are still characterized by poor outcome. Until now, transplant-eligible R/R DLBCL patients are treated with intensive salvage regimens followed by high-dose chemotherapy and autologous stem cell transplantation (ASCT) which, however, only cures a limited number of patients. It is most likely that in patients with early relapse after chemoimmunotherapy, chimeric antigen receptor (CAR) T-cells will replace high-dose chemotherapy and ASCT. So far, transplant-ineligible patients have mostly been treated in palliative intent. Recently, a plethora of novel agents comprising new monoclonal antibodies, antibody drug conjugates (ADC), bispecific antibodies, and CAR T-cells have emerged and have significantly improved outcome of patients with R/R DLBCL. In this review, we summarize our current knowledge on the usage of novel drugs and approaches for the treatment of patients with R/R DLBCL.

Concurrent lung adenocarcinoma and bladder diffuse large B-cell lymphoma: a case report and literature review

Lung adenocarcinoma is one of the most common solid tumors, and diffuse large B-cell lymphoma (DLBCL) is the most common histological subtype of adult non-Hodgkin’s lymphoma. Although extra-nodular lesions are frequently observed in patients with DLBCL, urinary bladder involvement is rare. We report the case of a 77-year-old woman with lung adenocarcinoma who was diagnosed with a second primary bladder DLBCL, 9 months after treatment with molecular targeted drugs. Simultaneous therapies for her lymphoma with lenalidomide and rituximab and a tyrosine kinase inhibitor therapy for her lung cancer were both effective. This result was consistent with previous reports suggesting that patients unable to tolerate intensive chemotherapy could benefit from targeted therapies. Current research into the use of lenalidomide for the treatment of lymphomas and solid tumors is promising in terms of exploring immunotherapy as an alternative option for patients with concurrent solid tumors and lymphomas who have poor tolerance to radiotherapy and chemotherapy.

T Cell Defects and Immunotherapy in Chronic Lymphocytic Leukemia

In the past few years, independent studies have highlighted the relevance of the tumor microenvironment (TME) in cancer, revealing a great variety of TME-related predictive markers, as well as identifying novel therapeutic targets in the TME. Cancer immunotherapy targets different components of the immune system and the TME at large in order to reinforce effector mechanisms or relieve inhibitory and suppressive signaling. Currently, it constitutes a clinically validated treatment for many cancers, including chronic lymphocytic leukemia (CLL), an incurable malignancy of mature B lymphocytes with great dependency on microenvironmental signals. Although immunotherapy represents a promising therapeutic option with encouraging results in CLL, the dysfunctional T cell compartment remains a major obstacle in such approaches. In the scope of this review, we outline the current immunotherapeutic treatment options in CLL in the light of recent immunogenetic and functional evidence of T cell impairment. We also highlight possible approaches for overcoming T cell defects and invigorating potent anti-tumor immune responses that would enhance the efficacy of immunotherapy.

Circulating myeloid-derived suppressor cells and regulatory T cells as immunological biomarkers in refractory/relapsed diffuse large B-cell lymphoma: translational results from the R2-GDP-GOTEL trial

Background

The search for immunological markers with ability of predicting clinical outcome is a priority in lymphomas, and in cancer in general. It is well known that some immunomodulatory cells, such as myeloid derived suppressor cells (MDSCs) or regulatory T cells (Tregs), are recruited by tumors, jeopardizing antitumor immunosurveillance. In this work, we have studied blood levels of these immunosuppressive cells in patients with relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL), prior to and along the course of the experimental rituximab, gemcitabine, dexamethasone, and cisplatin (R2-GDP) schedule, as a translational substudy of the R2-GDP-GOTEL trial (EudraCT Number: 2014-001620-29), which included lenalidomide as an immunomodulator.

Methods

Blood samples were taken before treatment, at cycle 3 and end of induction. Samples were analyzed by flow cytometry. Non-parametric tests were used. Mann-Whitney U test was used to compare basal cells distributions, and Wilcoxon test was considered to compare cells distribution at different times. Spearman test was performed to measure the degree of association between cell populations.

Results

In this study, MDSC and Treg circulating concentration was found increased in all patients compared with a healthy control group and decreased after treatment only in patients with longest overall survival (>24 months), reaching the levels of the healthy group. Likewise, the number of inhibited T lymphocytes expressing Programmed Death-1 (PD-1) were increased in peripheral blood from patients and decreased on the treatment, whereas activated T lymphocytes increased after therapy in those with better overall survival.

Conclusions

In conclusion, blood concentration of MDSCs and Treg cells may be good prognostic markers for overall survival after 2 years in R/R DLBCL. These results point to a possible role of these elements in the immunosuppression of these patients, as assessed by the circulating activated and inhibited T lymphocytes, and therefore, they may be considered as therapeutic targets in DLBCL.

Targeted Treatment of Follicular Lymphoma

Follicular lymphoma (FL) is the most common indolent B-cell lymphoma. Advanced stage disease is considered incurable and is characterized by a prolonged relapsing/remitting course. A significant minority have less favorable outcomes, particularly those with transformed or early progressive disease. Recent advances in our understanding of the unique genetic and immune biology of FL have led to increasingly potent and precise novel targeted agents, suggesting that a chemotherapy-future may one day be attainable. The current pipeline of new therapeutics is unprecedented. Particularly exciting is that many agents have non-overlapping modes of action, offering potential new combinatorial options and synergies. This review provides up-to-date clinical and mechanistic data on these new therapeutics. Ongoing dedicated attention to basic, translational and clinical research will provide further clarity as to when and how to best use these agents, to improve efficacy without eliciting unnecessary toxicity.

Immune-modulatory effects of lenalidomide inhibited the progression of lesions in a vitiligo mouse model

Vitiligo, an autoimmune disorder, is associated with altered cytokine levels and T lymphocytes. Lenalidomide modulates immune system components by altering cytokine production and regulating T-cell stimulation. In this study, effect of lenalidomide was checked on the development of vitiligo lesions, level of various cytokines, and T lymphocytes in the mouse model. The vitiligo mouse model was developed by immunizing C57BL/6 mouse with anti-mouse tyrosine-related protein 2. Lenalidomide was orally given to mice daily, and the effect was observed on the development of vitiligo lesions. The level of T lymphocytes in blood was checked by flow cytometry. Serum cytokine levels were checked by enzyme-linked immunosorbent assay. Vitiligo lesions were found significantly smaller in lenalidomide-treated mice models. It significantly decreased the serum levels of IFN-γ, TNF-α, IL-1β, and IL-6 but elevated the levels of IL-4 and IL-10. It non-significantly elevated CD4⁺ /CD8⁺ T-cell ratio. Lenalidomide had an inhibitory effect on the development of vitiligo lesions in mice models by suppressing the serum level of pro-inflammatory cytokines and increasing anti-inflammatory cytokine levels. It modulated the immune response in vitiligo mice models toward an anti-inflammatory profile suggesting its use in the management of vitiligo.

"Re-educating" Tumor Associated Macrophages as a Novel Immunotherapy Strategy for Neuroblastoma

Neuroblastoma is the most common extracranial pediatric tumor and often presents with metastatic disease, and patients with high-risk neuroblastoma have survival rates of ~50%. Neuroblastoma tumorigenesis is associated with the infiltration of various types of immune cells, including myeloid derived suppressor cells, tumor associated macrophages (TAMs), and regulatory T cells, which foster tumor growth and harbor immunosuppressive functions. In particular, TAMs predict poor clinical outcomes in neuroblastoma, and among these immune cells, TAMs with an M2 phenotype comprise an immune cell population that promotes tumor metastasis, contributes to immunosuppression, and leads to failure of radiation or checkpoint inhibitor therapy. This review article summarizes the role of macrophages in tumor angiogenesis, metastasis, and immunosuppression in neuroblastoma and discusses the recent advances in "macrophage-targeting strategies" in neuroblastoma with a focus on three aspects: (1) inhibition of macrophage recruitment, (2) targeting macrophage survival, and (3) reprogramming of macrophages into an immunostimulatory phenotype.

Natural killer cells: a review of biology, therapeutic potential and challenges in treatment of solid tumors

Natural killer (NK) cells lead immune surveillance against cancer and early elimination of small tumors. Owing to their ability to engage tumor targets without the need of specific antigen, the therapeutic potential of NK cells has been extensively explored in hematological malignancies. In solid tumors, however, their role in the clinical arena remains poorly exploited despite a broad accumulation of preclinical data. In this article, we review our current knowledge of NK cells’ biology, and highlight the challenges facing NK cell antitumor strategies in solid tumors. We further summarize the abundant preclinical attempts at overcoming these challenges, present past and ongoing clinical trial data and finally discuss the potential impact of novel insights on the development of NK cell-based therapies.

Low absolute NK cell counts in peripheral blood are associated with inferior survival in patients with mantle cell lymphoma

BACKGROUND

Although risk stratification of mantle cell lymphoma (MCL) is most frequently performed using the simplified MCL International Prognostic Index (sMIPI), the identification of host-related factors and tumor microenvironment, including absolute monocyte counts (AMC) and peripheral blood T lymphocyte subsets, especially absolute natural killer cell counts (ANKC) has been suggested to be critical in the prediction of prognosis and the guidance of treatment.

OBJECTIVE

This study was aimed at investigating whether peripheral blood ANKC and AMC at diagnosis had an impact on MCL prognosis.

METHODS

A total of 92 newly diagnosed MCL patients was enrolled in this retrospective study. Flow cytometric analysis was conducted on fresh peripheral blood samples with a FACSCalibur flow cytometer (BD Biosciences, San Jose, CA, USA).

RESULTS

The median follow-up was 42 months (range, 2-144 months) and the median overall survival (OS) of all cases was 45 months. High AMC (> 0.6 × 109/L) was the parameter associated with inferior progression free survival (PFS) (P= 0.044) and poor OS (P= 0.028) while low ANKC (⩽ 0.1 × 109/L) was associated with unfavorable OS (P= 0.023) by univariable analysis. Multivariable analysis revealed that only low ANKC (⩽ 0.1 × 109/L) was statistically significant in worse OS (P= 0.009) independent of sMIPI.

CONCLUSIONS

Low ANKC (⩽ 0.1 × 109/L) proved to be a significant predictor of inferior OS in patients with MCL.

Impact of lenalidomide exposure on blood cell collection for autotransplants in persons with POEMS syndrome

INTRODUCTION

Lenalidomide is an effective therapy of POEMS syndrome. However, there is concern that exposure to lenalidomide may reduce the efficiency of blood cell collection in persons who may eventually receive an autotransplant. We studied the impact of lenalidomide therapy on subsequent blood cell mobilization and collection including frequency of blood CD34+ cells and CXCR4 expression before and after mobilization with cyclophosphamide and granulocyte-colony stimulating factor (G-CSF).

MATERIAL AND METHODS

Forty-three subjects with POEMS were assigned to receive lenalidomide and dexamethasone for 2-4 28 d cycles (n = 19) or no therapy (n = 24). All subjects then received cyclophosphamide and G-CSF. Neither cohort had substantial numbers of blood CD34+ cells before mobilization.

RESULTS

Mobilization increased blood CD34+ frequency in lenalidomide-treated subjects and controls similarly (0.25% (95% confidence interval (CI): 0.03-1.39% vs. 0.32%, 0.04-1.47%), p = 0.472). Increases in blood CD34+ numbers were also similar (10 × 10⁶/l) (5-77 × 10⁶/l) vs. 14 × 10⁶/l (6-101 × 10⁶/l), p = 0.312). Mean CXCR4 fluorescence intensity on bone marrow cells from controls decreased from 58 ±34 (mean ± SD) to 31 ±16 after mobilization (p = NS). In contrast, mean CXCR4 intensity on bone marrow cells in lenalidomide-treated subjects increased from 55 ±43 to 89 ±40 (p = 0.017, comparing the deviation between two groups). Median numbers of CD34+ cells collected in lenalidomide-treated subjects and controls were 2.3 × 10⁶/kg (0.6-6.8 × 10⁶/kg) and 2.810⁶/kg (1.0-8.9 × 10⁶/kg; p = 0.521).

CONCLUSIONS

Brief lenalidomide treatment for POEMS did not reduce numbers of CD34+ blood cells collected but increased CXCR4 expression on bone marrow CD34+ cells.

Allogeneic stem cell transplantation and subsequent treatments as a comprehensive strategy for long-term survival of multiple myeloma patients

We evaluated 71 patients treated with allogeneic hematopoietic cell transplantation (allo-HCT) for multiple myeloma (MM). Forty-three patients (61%) received allo-HCT after the first line of therapy. Fifty-eight patients (82%) had chemosensitive disease at the time of allo-HCT. A HLA-matched related or unrelated donor was available for 68 patients (96%). Non-myeloablative or reduced-intensity conditioning regimen and peripheral blood hematopoietic cells as a graft source were used in most patients. The cumulative incidence of grade II-IV acute GVHD at day +100 and chronic GVHD at 5 years was 13% (95% CI 7-23%) and 35% (95% CI 24-46), respectively. Non-relapse mortality and relapse/progression incidence at 5 years were 12% (95% CI 5-23) and 65% (95% CI 49-76), respectively. With a median follow-up in survivors of 100 months (range 16-186), the 5-year PFS and OS were 39% (95% CI 27-52) and 60% (95% CI 55-77), respectively. On multivariate analysis: age >55 years was associated with both a reduced PFS (RR 2.11, 95% CI 1.15-3.87) and OS (RR 5.53, 95% CI 2.22-13.76); chemorefractory disease at allo-HCT was associated with both reduced PFS (RR 3.09, 95% CI 1.37-7.00) and OS (RR 3.19, 95% CI 1.23-8.22). At relapse, 24 patients (56%) received bortezomib, 28 (65%) lenalidomide, 11 (26%) pomalidomide, 16 (37%) donor lymphocytes infusion as part of salvage therapy after allo-HCT relapse. Median PFS from time of salvage treatment was 7 months (range 0-113 months) for bortezomib-based therapy, 14 months (range 0-79 months) for lenalidomide and 10 months (range 1-28) for pomalidomide. Allo-HCT is a feasible and effective strategy in selected patients with MM and could be an effective platform for subsequent therapies.

Prognostic relevance of lymphocytopenia, monocytopenia and lymphocyte-to-monocyte ratio in primary myelodysplastic syndromes: a single center experience in 889 patients

Current prognostic models for myelodysplastic syndromes (MDS), including the Revised International Prognostic Scoring System (IPSS-R), do not account for host immunity. We retrospectively examined the prognostic relevance of monocytopenia, lymphocytopenia and lymphocyte-to-monocyte ratio (LMR) in a cohort of 889 patients with primary MDS. After a median follow-up of 27 months, 712 (80%) deaths and 116 (13%) leukemic transformation were documented. In univariate analysis, subnormal absolute lymphocyte count (ALC) <0.9 × 10⁹/l; P=0.001), ALC<1.2 × 10⁹/l (P=0.0002), subnormal absolute monocyte count (AMC) <0.3 × 10⁹/l (P=0.0003), LMR (P⩽0.0001) and LMR⩾5 (P=0.03) were all associated with inferior overall survival. In multivariable analysis that included other risk factors, significance was retained for LMR (P=0.02) and became borderline for ALC <1.2 × 10⁹/l (P=0.06). Analysis in the context of IPSS-R resulted in P-values of 0.06 for ALC<1.2 × 10⁹/l, 0.7 for monocytopenia and 0.2 for LMR. Leukemia-free survival was not affected by ALC, AMC or LMR. The observations from the current study suggest a possible detrimental role for altered host immunity in primary MDS, which might partly explain the therapeutic benefit of immune-directed therapy, including the use of immune modulators; however, IPSS-R-independent prognostic value for either ALC or AMC was limited.

PD-1 mRNA expression in peripheral blood cells and its modulation characteristics in cancer patients

Immune checkpoint inhibitors that block the PD-1/PD-L1 signaling pathway have been used to treat a wide variety of cancers. Although results have been promising, significant inter-individual and inter-tumor variability has been observed. It is believed that better clinical outcome could be achieved if the treatment was individually designed based on the functional status of the PD-1/PD-L1 signaling and the cellular immunity. In this study, we analyzed the mRNA expression of PD-1 and other immunomodulatory genes in peripheral blood from cancer patients, and immunomodulatory gene expression during radiotherapy and immunomodulation therapy with cytokines. Our results show that the PD-1 mRNA expression is significantly increased in peripheral blood in cancer patients. Anti-cancer treatments can significantly modulate the PD-1 expression, but this is largely dependent on the initial immune status. Moreover, the PD-1 expression on peripheral lymphocytes can be immunoactivation-derived. These results suggest that the regulation and expression pattern of PD-1/PD-L1 signal is complicated which will influence the effect of blockade of the PD-1/PD-L1 signaling pathway for cancer treatment. Through combined analysis of PD-1, CTLA-4, and other immune markers in peripheral blood, we may accurately evaluate the functional status of PD-1/PD-L1 signaling and cellular immunity, thereby providing clues for guiding anti-PD-1 or anti-PD-L1 treatment.

A calcium- and calpain-dependent pathway determines the response to lenalidomide in myelodysplastic syndromes

Despite the high response rates of individuals with myelodysplastic syndrome (MDS) with deletion of chromosome 5q (del(5q)) to treatment with lenalidomide (LEN) and the recent identification of cereblon (CRBN) as the molecular target of LEN, the cellular mechanism by which LEN eliminates MDS clones remains elusive. Here we performed an RNA interference screen to delineate gene regulatory networks that mediate LEN responsiveness in an MDS cell line, MDSL. We identified GPR68, which encodes a G-protein-coupled receptor that has been implicated in calcium metabolism, as the top candidate gene for modulating sensitivity to LEN. LEN induced GPR68 expression via IKAROS family zinc finger 1 (IKZF1), resulting in increased cytosolic calcium levels and activation of a calcium-dependent calpain, CAPN1, which were requisite steps for induction of apoptosis in MDS cells and in acute myeloid leukemia (AML) cells. In contrast, deletion of GPR68 or inhibition of calcium and calpain activation suppressed LEN-induced cytotoxicity. Moreover, expression of calpastatin (CAST), an endogenous CAPN1 inhibitor that is encoded by a gene (CAST) deleted in del(5q) MDS, correlated with LEN responsiveness in patients with del(5q) MDS. Depletion of CAST restored responsiveness of LEN-resistant non-del(5q) MDS cells and AML cells, providing an explanation for the superior responses of patients with del(5q) MDS to LEN treatment. Our study describes a cellular mechanism by which LEN, acting through CRBN and IKZF1, has cytotoxic effects in MDS and AML that depend on a calcium- and calpain-dependent pathway.

Development of an Enhanced Phenotypic Screen of Cytotoxic T-Lymphocyte Lytic Granule Exocytosis Suitable for Use with Synthetic Compound and Natural Product Collections

We previously developed an assay of cytotoxic T-lymphocyte lytic granule exocytosis based on externalization of LAMP-1/CD107A using nonphysiological stimuli to generate maximal levels of exocytosis. Here, we used polystyrene beads coated with anti-CD3 antibodies to stimulate cells. Light scatter let us distinguish cells that contacted beads from cells that had not, allowing comparison of signaling events and exocytosis from stimulated and unstimulated cells in one sample. Bead stimulation resulted in submaximal exocytosis, making it possible to detect compounds that either augment or inhibit lytic granule exocytosis. Coupled with the assay's ability to distinguish responses in cells that have and have not contacted a stimulatory bead, it is possible to detect three kinds of compounds: inhibitors, stimulators, which cause exocytosis, and augmenters, which enhance receptor-stimulated exocytosis. To validate the assay, we screened a set of synthetic compounds identified using our previous assay and a library of 320 extracts prepared from tunicate-associated bacteria. One of the extracts augmented exocytosis threefold. Activity-guided fractionation and structure elucidation revealed that this compound is the known PKC activator teleocidin A-1. We conclude that our modified assay is suitable for screening synthetic compound plates and natural product collections, and will be useful for identifying immunologically active small molecules.

Autoimmune Syndromes Presenting as a Paraneoplastic Manifestation of Myelodysplastic Syndromes: Clinical Features, Course, Treatment and Outcome

Autoimmune manifestations (AIM) are reported in up to 10-30% of myelodysplastic syndromes (MDS) patients; this association is not well defined. We present herein a retrospective chart review of single center MDS patients for AIM, a case discussion and a literature review. Of 252 MDS patients examined, 11 (4.4%) had AIM around MDS diagnosis. International Prognostic Scoring System scores were: low or intermediate (int)-1 (n=7); int-2 or high (n=4). AIM were: culture negative sepsis (n=7); inflammatory arthritis (n=3); vasculitis (n=4); sweats; pericarditis; polymyalgia rheumatica (n=2 each); mouth ulcers; pulmonary infiltrates; suspicion for Behcet's; polychondritis and undifferentiated (n=1 each). AIM treatment and outcome were: prednisone +/- steroid sparing agents, n=8, ongoing symptoms in 5; azacitidine (n=3), 2 resolved; and observation, n=1, ongoing symptoms. At a median follow up of 13 months, seven patients are alive. In summary, 4.4% of MDS patients presented with concomitant AIM. MDS should remain on the differential diagnosis of patients with inflammatory symptoms.

Treatment of Cancer Pain by Targeting Cytokines

Inflammation is one of the most important causes of the majority of cancer symptoms, including pain, fatigue, cachexia, and anorexia. Cancer pain affects 17 million people worldwide and can be caused by different mediators which act in primary efferent neurons directly or indirectly. Cytokines can be aberrantly produced by cancer and immune system cells and are of particular relevance in pain. Currently, there are very few strategies to control the release of cytokines that seems to be related to cancer pain. Nevertheless, in some cases, targeted drugs are available and in use for other diseases. In this paper, we aim to review the importance of cytokines in cancer pain and targeted strategies that can have an impact on controlling this symptom.

Emerging immunotherapy and strategies directly targeting B cells for the treatment of diffuse large B-cell lymphoma

During the last decade, significant prolonged survival in diffusive large B-cell lymphoma (DLBCL) has been observed. The efficacy of initial treatment improved mostly due to addition of a chimeric anti-CD20 monoclonal antibody (rituximab) to standard chemotherapeutic regimens. Moreover, accurate understanding of DLBCL pathogenesis and remarkable progress in gene expression profiling have led to the development of a variety of tumor-specific regimens. Novel agents target directly the pathways involved in signal transduction, lead to apoptosis and cancer cells differentiation. In this article, we mainly focus on new treatment options, such as monoclonal antibodies, tyrosine kinase inhibitors and immunomodulatory drugs, currently investigated in aggressive B-cell lymphoma with particular attention to DLBCL type.

Mechanisms of Action of Lenalidomide in B-Cell Non-Hodgkin Lymphoma

Lenalidomide is an orally active immunomodulatory drug that has direct antineoplastic activity and indirect effects mediated through multiple types of immune cells found in the tumor microenvironment, including B, T, natural killer (NK), and dendritic cells. Recently, the E3 ubiquitin ligase cereblon was identified as a molecular target that may underlie the effects of lenalidomide on tumor cells, as well as on cells in the tumor microenvironment. Decreases in cereblon attenuate these effects and also confer resistance to lenalidomide. Tumoricidal effects of lenalidomide are associated with reduced interferon regulatory factor 4, a downstream target of cereblon. Lenalidomide stimulates proliferation and activation of NK cells, thereby enhancing NK cell-mediated cytotoxicity and antibody-dependent cellular cytotoxicity. These effects appear to be secondary to cytokine production from T cells. Lenalidomide has been shown to produce synergistic effects in experimental models when evaluated in combination with rituximab, dexamethasone, bortezomib, and B-cell receptor signaling inhibitors, consistent with mechanisms complementary to these agents. These experimental findings have translated to the clinic, where single-agent use displays durable responses in relapsed/refractory non-Hodgkin lymphoma, and combination with rituximab and other agents leads to improved responses at first line and in relapsed/refractory disease. The activity of lenalidomide is evident across multiple lymphoma subtypes, including indolent and aggressive forms. The interaction among cell types in the immune microenvironment is increasingly recognized as important to tumor cell recognition and destruction, as well as to protection of normal immune cells, as reflected by lenalidomide studies across multiple types of B-cell lymphomas.

Immunomodulation of Selective Naive T Cell Functions by p110δ Inactivation Improves the Outcome of Mismatched Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (HSCT) can treat certain hematologic malignancies due to the graft versus leukemia (GvL) effect but is complicated by graft versus host disease (GvHD). Expression of the p110δ catalytic subunit of the phosphoinositide 3-kinase pathway is restricted to leukocytes, where it regulates proliferation, migration, and cytokine production. Here, in a mouse model of fully mismatched hematopoietic cell transplantation (HCT), we show that genetic inactivation of p110δ in T cells leads to milder GvHD, whereas GvL is preserved. Inactivation of p110δ in human lymphocytes reduced T cell allorecognition. We demonstrate that both allostimulation and granzyme B expression were dependent on p110δ in naive T cells, which are the main mediators of GvHD, whereas memory T cells were unaffected. Strikingly, p110δ is not mandatory for either naive or memory T cells to mediate GvL. Therefore, immunomodulation of selective naive T cell functions by p110δ inactivation improves the outcome of allogeneic HSCT.

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Genetic p110δ inactivation in donor naive T cells mitigates GvHD in mice

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Pharmacological p110δ inactivation in human T cells reduces alloreactivity

High level of full-length cereblon mRNA in lower risk myelodysplastic syndrome with isolated 5q deletion is implicated in the efficacy of lenalidomide

Downregulation of cereblon (CRBN) gene expression is associated with resistance to the immunomodulatory drug lenalidomide and poor survival outcomes in multiple myeloma (MM) patients. However, the importance of CRBN gene expression in patients with myelodysplastic syndrome (MDS) and its impact on lenalidomide therapy are not clear. In this study, we evaluate cereblon expression in mononuclear cells isolated from bone marrow [23 lower risk MDS patients with isolated 5q deletion (5q-), 37 lower risk MDS patients with chromosome 5 without the deletion of long arms (non-5q-), and 24 healthy controls] and from peripheral blood (38 patients with 5q-, 52 non-5q- patients and 25 healthy controls) to gain insight into, firstly, the role of cereblon in lower risk MDS patients with or without 5q deletion and, secondly, into the mechanisms of lenalidomide action. Patients with 5q- lower risk MDS have the highest levels of CRBN mRNA in comparison with both lower risk MDS without the deletion of long arms of chromosome 5 and healthy controls. CRBN gene expression was measured using the quantitative TaqMan real-time PCR. High levels of CRBN mRNA were detected in all lenalidomide responders during the course of therapy. A significant decrease of the CRBN mRNA level during lenalidomide treatment is associated with loss of response to treatment and disease progression. These results suggest that, similar to the treatment of MM, high levels of full-length CRBN mRNA in lower risk 5q- patients are necessary for the efficacy of lenalidomide.

Safety and activity of lenalidomide and rituximab in untreated indolent lymphoma: an open-label, phase 2 trial

BACKGROUND

Standard treatments for indolent non-Hodgkin lymphomas are often toxic, and most patients ultimately relapse. Lenalidomide, an immunomodulatory agent, is effective as monotherapy for relapsed indolent non-Hodgkin lymphoma. We assessed the efficacy and safety of lenalidomide plus rituximab in patients with untreated, advanced stage indolent non-Hodgkin lymphoma.

METHODS

In this phase 2 trial, undertaken at one instution, patients with follicular lymphoma and marginal zone lymphoma were given lenalidomide, orally, at 20 mg/day on days 1-21 of each 28-day cycle. For patients with small lymphocytic lymphoma, dosing began at 10 mg/day to avoid tumour flare, with an escalation of 5 mg/month to 20 mg/day. Rituximab was given at 375 mg/m(2) as an intravenous infusion on day 1 of each cycle. Patients responding after six cycles could continue therapy for up to 12 cycles. The primary endpoint was overall response, defined as the proportion of patients who achieved a partial or complete response; patients were assessed for response if they had any post-baseline tumour assessment. This trial is registered with ClinicalTrials.gov, number NCT00695786.

FINDINGS

110 patients with follicular lymphoma (n=50), marginal zone lymphoma (n=30), and small lymphocytic lymphoma (n=30) were enrolled from June 30, 2008, until Aug 12, 2011. 93 of 103 evaluable patients had an overall response (90%, 95% CI 83-95). Complete responses occurred in 65 (63%, 95% CI 53-72) and partial responses in 28 patients (27%, 19-37). Of 46 evaluable patients with follicular lymphoma, 40 (87%) patients had a complete response and five (11%) had a partial response. Of 27 evaluable patients with marginal zone lymphoma, 18 (67%) had a complete response and six (22%) had a partial response. Of 30 evaluable patients with small lymphocytic lymphoma, seven (23%) had a complete response and 17 (57%) had a partial response. The most common grade 3 or 4 adverse events were neutropenia (38 [35%] of 110 patients), muscle pain (ten [9%]), rash (eight [7%]), cough, dyspnoea, or other pulmonary symptoms (five [5%]), fatigue (five [5%]), thrombosis (five [5%]), and thrombocytopenia (four [4%]).

INTERPRETATION

Lenalidomide plus rituximab is well tolerated and highly active as initial treatment for indolent non-Hodgkin lymphoma. An international phase 3 study (NCT01476787) to compare this regimen with chemotherapy in patients with untreated follicular lymphoma is in progress.

FUNDING

Celgene Corporation and Richard Spencer Lewis Memorial Foundation and Cancer Center Support Grant.

Lenalidomide-based maintenance therapy reduces TNF receptor 2 on CD4 T cells and enhances immune effector function in acute myeloid leukemia patients

A major limitation to improved outcomes in acute myelogenous leukemia (AML) is relapse resulting from leukemic cells that persist at clinical remission. Regulatory T cells (Tregs), which are increased in AML patients, can contribute to immune evasion by residual leukemic cells. Tumor necrosis factor (TNF), a pro-inflammatory cytokine present at high levels within patients, can induce TNF receptor-2 (TNFR2) expression on Tregs. We hypothesized that since TNFR2 is required for Treg stabilization and TNFR2+ Tregs are potent suppressors, targeting TNFR2+ Tregs may restore the effectiveness of immune-surveillance mechanisms. In this pilot study, we report AML patients in clinical remission have substantially increased levels of TNFR2+ T cells, including TNFR2+ Tregs and impaired effector CD4 T cell function with reduced IL-2 and IFNγ production. The immunomodulatory drug, lenalidomide, and the demethylating agent, azacitidine have been moderately successful in treating AML patients, but their combined effects on TNFR2+ T cells, including Tregs are currently unknown. Our data indicates that although treatment with lenalidomide and azacitidine increased cytokine production by effector T cells in all patients, durable clinical remissions may be observed in patients with a concomitant reduction in TNFR2+ T cells and TNFR2+ Tregs. In vitro studies further demonstrated that lenalidomide can reduce TNFR2 expression and can augment effector cytokine production by T cells, which can be further enhanced by azacitidine. These results indicate that reduction of TNFR2+ T cells in AML postremission phase may result from combined azacitidine/lenalidomide therapy and may contribute to an improved clinical outcome.

Transfection of chimeric anti-CD138 gene enhances natural killer cell activation and killing of multiple myeloma cells

Reprogramming of NK cells with a chimeric antigen receptor (CAR) proved an effective strategy to increase NK cell reactivity and recognition specificity toward tumor cells. To enhance the cytotoxicity of NK cells against CD138-positive multiple myeloma (MM) cells, we generated genetically modified NK-92MI cells carrying a CAR that consists of an anti-CD138 single-chain variable fragment (scFv) fused to the CD3ζ chain as a signaling moiety. The genetic modification through a lentiviral vector did not affect the intrinsic cytolytic activity of NK-92MI toward human erythroleukemic cell line K562 cells or CD138-negative targets. However, these retargeted NK-92MI (NK-92MI-scFv) displayed markedly enhanced cytotoxicity against CD138-positive human MM cell lines (RPMI8226, U266 and NCI-H929) and primary MM cells at various effector-to-target ratios (E:T) as compared to the empty vector-transfected NK-92MI (NK-92MI-mock). In line with the enhanced cytotoxicity of NK-92MI-scFv, significant elevations in the secretion of granzyme B, interferon-γ and proportion of CD107a expression were also found in NK-92MI-scFv in response to CD138-positive targets compared with NK-92MI-mock. Most importantly, the enhancement in the cytotoxicity of NK-92MI-scFv did not attenuate with 10Gy-irradiation that sufficiently blocked cell proliferation. Moreover, the irradiated NK-92MI-scFv exerted definitely intensified anti-tumor activity toward CD138-positive MM cells than NK-92MI-mock in the xenograft NOD-SCID mouse model. This study provides the rationale and feasibility for adoptive immunotherapy with CD138-specific CAR-modified NK cells in CD138-positive plasmacytic malignancies, which potentially further improves remission quality and prolongs the remission duration of patients with MM after upfront chemotherapy.

Expression of PD-L1, PD-L2, PD-1 and CTLA4 in myelodysplastic syndromes is enhanced by treatment with hypomethylating agents

Blockade of immune checkpoints is emerging as a new form of anticancer therapy. We studied the expression of programmed death ligand 1 (PD-L1), PD-L2, programmed death 1 (PD-1) and cytotoxic T lymphocyte-associated antigen 4 (CTLA4) mRNA in CD34+ cells from myelodysplastic syndrome (MDS), chronic myelomonocytic leukemia (CMML) and acute myeloid leukemia (AML) patients (N=124). Aberrant upregulation (⩾2-fold) was observed in 34, 14, 15 and 8% of the patients. Increased expression of these four genes was also observed in peripheral blood mononuclear cells (PBMNCs) (N=61). The relative expression of PD-L1 from PBMNC was significantly higher in MDS (P=0.018) and CMML (P=0.0128) compared with AML. By immunohistochemical analysis, PD-L1 protein expression was observed in MDS CD34+ cells, whereas stroma/non-blast cellular compartment was positive for PD-1. In a cohort of patients treated with epigenetic therapy, PD-L1, PD-L2, PD-1 and CTLA4 expression was upregulated. Patients resistant to therapy had relative higher increments in gene expression compared with patients who achieved response. Treatment of leukemia cells with decitabine resulted in a dose-dependent upregulation of above genes. Exposure to decitabine resulted in partial demethylation of PD-1 in leukemia cell lines and human samples. This study suggests that PD-1 signaling may be involved in MDS pathogenesis and resistance mechanisms to hypomethylating agents. Blockade of this pathway can be a potential therapy in MDS and AML.

Trial Watch: Lenalidomide-based immunochemotherapy

Lenalidomide is a synthetic derivative of thalidomide currently approved by the US Food and Drug Administration for use in patients affected by multiple myeloma (in combination with dexamethasone) and low or intermediate-1 risk myelodysplastic syndromes that harbor 5q cytogenetic abnormalities. For illustrative purposes, the mechanism of action of lenalidomide can be subdivided into a cancer cell-intrinsic, a stromal, and an immunological component. Indeed, lenalidomide not only exerts direct cell cycle-arresting and pro-apoptotic effects on malignant cells, but also interferes with their physical and functional interaction with the tumor microenvironment and mediates a robust, pleiotropic immunostimulatory activity. In particular, lenalidomide has been shown to stimulate the cytotoxic functions of T lymphocytes and natural killer cells, to limit the immunosuppressive impact of regulatory T cells, and to modulate the secretion of a wide range of cytokines, including tumor necrosis factor α, interferon γ as well as interleukin (IL)-6, IL-10, and IL-12. Throughout the last decade, the antineoplastic and immunostimulatory potential of lenalidomide has been investigated in patients affected by a wide variety of hematological and solid malignancies. Here, we discuss the results of these studies and review the status of clinical trials currently assessing the safety and efficacy of this potent immunomodulatory drug in oncological indications.

Natural killer cell biology: an update and future directions

Natural killer (NK) cells constitute a minor subset of normal lymphocytes that initiate innate immune responses toward tumor and virus-infected cells. They can mediate spontaneous cytotoxicity toward these abnormal cells and rapidly secrete numerous cytokines and chemokines to promote subsequent adaptive immune responses. Significant progress has been made in the past 2 decades to improve our understanding of NK cell biology. Here we review recent discoveries, including a better comprehension of the "education" of NK cells to achieve functional competence during their maturation and the discovery of "memory" responses by NK cells, suggesting that they might also contribute to adaptive immunity. The improved understanding of NK cell biology has forged greater awareness that these cells play integral early roles in immune responses. In addition, several promising clinical therapies have been used to exploit NK cell functions in treating patients with cancer. As our molecular understanding improves, these and future immunotherapies should continue to provide promising strategies to exploit the unique functions of NK cells to treat cancer, infections, and other pathologic conditions.

Very long-lasting remission of refractory T-large granular lymphocytes leukemia and myeloma by lenalidomide treatment

BACKGROUND

Large granular lymphocyte leukemias (LGLLs) represent a spectrum of biologically distinct lymphoproliferative diseases originating from either mature T cells (CD3+) or natural killer (NK) cells (CD3-). Both T-cell and NK-cell LGL leukemia can manifest as indolent or aggressive neoplasia. These rare lymphoproliferative disorders are often associated with autoimmune diseases and impaired hematopoiesis. Symptomatic patients are treated with immunosuppressive drugs. The co-association of T-LGLL with clonal B-cell disorders is reported in more than 10% of patients.

CASE PRESENTATION

We describe the case of a 57-yr-old white male patient with no history of autoimmune disorders, with refractory T-LGLL and myeloma who was treated with bortezomib and subsequently with lenalidomide. After 30 months of on-going lenalidomide therapy, the patient is in partial remission from myeloma and in continuous complete hematological remission from T-LGLL.

CONCLUSIONS

As far as we know, this is the first report of a patient with refractory T-LGLL treated with bortezomib and lenalidomide. As refractory T-LGLL is a challenging condition, we think that lenalidomide and bortezomib deserve further investigation.