Brentuximab vedotin as consolidation therapy after autologous stem-cell transplantation in patients with Hodgkin's lymphoma at risk of relapse or progression (AETHERA): a randomised, double-blind, placebo-controlled, phase 3 trial

Mechanisms of leukemia resistance to antibody dependent cellular cytotoxicity

Specific immunotherapy for acute leukemia remains a great unmet need. Native unmodified monoclonal antibody therapies, while promising, are inadequately effective for these malignancies, and multiple mechanisms for failure have been described. Antibody-dependent cellular cytotoxicity or phagocytosis is the primary modality of mAb-mediated cell killing in vivo, but ultimately leads to relapse of the leukemias, in model systems and in humans. By use of a T-cell receptor mimic mAb ESKM, derived against a WT1 peptide expressed in complex with HLA-A*02:01, whose only mechanism of therapeutic action is ADCC, we evaluated the mechanisms of leukemic relapse from its potent therapeutic action in mouse xenograft models of human leukemia. Leukemia escape was not associated with loss of the antigenic target, downregulation of cell surface HLA, antibody pharmacokinetic or biodistribution issues, or development of leukemia cell-intrinsic resistance to ADCC. Interestingly, the rapidity of leukemic growth determined whether leukemia was able to evade cytotoxicity independent of the presence of sufficient effector cells. By engineering leukemia cells with upregulated p27^Kip1 and slower cell cycling times, we show that relapse was inversely correlated with growth rates resulting in the eventual inadequacy of effector to target ratio. Moreover, lack of migration of effector cells into lymphomatous pockets of ALL also allowed local escape. Successful leukemia therapy with mAb might therefore be improved in similar situations by combination with measures to reduce burden and slow leukemia cell growth.

Prevention and management of hepatitis B virus reactivation in patients with hematological malignancies treated with anticancer therapy

Hepatitis due to hepatitis B virus (HBV) reactivation can be severe and potentially fatal, but is preventable. HBV reactivation is most commonly reported in patients receiving cancer chemotherapy, especially rituximab-containing therapy for hematological malignancies and those receiving stem cell transplantation. All patients with hematological malignancies receiving anticancer therapy should be screened for active or resolved HBV infection by blood tests for hepatitis B surface antigen (HBsAg) and antibody to hepatitis B core antigen (anti-HBc). Patients found to be positive for HBsAg should be given prophylactic antiviral therapy to prevent HBV reactivation. For patients with resolved HBV infection, no standard strategy has yet been established to prevent HBV reactivation. There are usually two options. One is pre-emptive therapy guided by serial HBV DNA monitoring, whereby antiviral therapy is given as soon as HBV DNA becomes detectable. However, there is little evidence regarding the optimal interval and period of monitoring. An alternative approach is prophylactic antiviral therapy, especially for patients receiving high-risk therapy such as rituximab, newer generation of anti-CD20 monoclonal antibody, obinutuzumab or hematopoietic stem cell transplantation. This strategy may effectively prevent HBV reactivation and avoid the inconvenience of repeated HBV DNA monitoring. Entecavir or tenofovir are preferred over lamivudine as prophylactic therapy. Although there is no well-defined guideline on the optimal duration of prophylactic therapy, there is growing evidence to recommend continuing prophylactic antiviral therapy for at least 12 mo after cessation of chemotherapy, and even longer for those who receive rituximab or who had high serum HBV DNA levels before the start of immunosuppressive therapy. Many novel agents have recently become available for the treatment of hematological malignancies, and these agents may be associated with HBV reactivation. Although there is currently limited evidence to guide the optimal preventive measures, we recommend antiviral prophylaxis in HBsAg-positive patients receiving novel treatments, especially the Bruton tyrosine kinase inhibitors and the phosphatidylinositol 3-kinase inhibitors, which are B-cell receptor signaling modulators and reduce proliferation of malignant B-cells. Further studies are needed to clarify the risk of HBV reactivation with these agents and the best prophylactic strategy in the era of targeted therapy for hematological malignancies.

Chemotherapy remains an essential element of personalized care for persons with lung cancers

Molecularly targeted and immunotherapies have improved the care of patients with lung cancers. These successes have rallied calls to replace or avoid chemotherapy. Yet, even in this era of precision medicine and exciting advances, cytotoxic chemotherapies remain an essential component of lung cancer treatment. In the setting of locoregional disease, chemotherapy is the only systemic therapy thus far proven to enhance curability when combined with surgery or radiation. In the metastatic setting, chemotherapy can improve the length and quality of life in many patients. Chemotherapy remains the mainstay of care for individuals whose cancers with oncogenic drivers have acquired resistance to targeted agents. Chemotherapy also has the potential to modulate the immune system to enhance the effectiveness of immune checkpoint inhibitors. In this context, chemotherapy should be framed as a critical component of the armamentarium available for optimizing cancer care rather than an unfortunate anachronism. We examine the role of chemotherapy with precision medicine in the current care of patients with lung cancers, as well as opportunities for future integration in combinations with targeted agents, angiogenesis inhibitors, immunotherapies, and antibody drug conjugates.

Evaluation of the Risk of Relapse in Classical Hodgkin Lymphoma at Event-Free Survival Time Points and Survival Comparison With the General Population in British Columbia

Purpose

Studies in classical Hodgkin lymphoma (cHL) typically measure the time to events from diagnosis. We evaluated the risk of relapse at event-free survival time points in cHL and compared the risk of death to expected mortality rates in British Columbia (BC).

Methods

The BC Cancer Agency Lymphoid Cancer Database was screened to identify all patients age 16 to 69 years diagnosed with cHL between 1989 and 2012 treated with the chemotherapy regimen of doxorubicin, bleomycin, vinblastine, and dacarbazine (or equivalent). We compared the observed mortality to the general population using age-, sex-, and calendar period–generated expected mortality rates from BC life-tables. Relative survival was calculated using a conditional approach and expressed as a standardized mortality ratio of observed-to-expected deaths.

Results

One thousand four hundred two patients were identified; 749 patients were male (53%), the median age was 32 years, and 68% had advanced-stage disease. The median follow-up time was 8.4 years. Seventy-two percent of relapses occurred within the first 2 years of diagnosis. For all patients, the 5-year risk of relapse from diagnosis was 18.1% but diminished to 5.6% for patients remaining event free at 2 years. For advanced-stage patients who were event free at 2 years, the 5-year risk of relapse was only 7.6%, and for those who were event free at 3 years, it was comparable to that of limited-stage patients (4.1% v 2.5%, respectively; P = .07). Furthermore, international prognostic score ≥ 4 and bulky disease were no longer prognostic in patients who were event free at 1 year. Although the relative survival improved as patients remained in remission, it did not normalize compared with the general population.

Conclusion

Patients with cHL who are event free at 2 years have an excellent outcome regardless of baseline prognostic factors. All patients with cHL had an enduring increased risk of death compared with the general population.

Antibody-Drug Conjugates for Cancer Therapy

Antibody–drug conjugates (ADCs) take advantage of the specificity of a monoclonal antibody to deliver a linked cytotoxic agent directly into a tumour cell. The development of these compounds provides exciting opportunities for improvements in patient care. Here, we review the key issues impacting on the clinical success of ADCs in cancer therapy. Like many other developing therapeutic classes, there remain challenges in the design and optimisation of these compounds. As the clinical applications for ADCs continue to expand, key strategies to improve patient outcomes include better patient selection for treatment and the identification of mechanisms of therapy resistance.

Risk factors predicting outcomes for primary refractory hodgkin lymphoma patients treated with salvage chemotherapy and autologous stem cell transplantation

We aimed to identify risk factors that predict functional imaging (FI) response to salvage chemotherapy and evaluate outcomes following autologous stem cell transplant (ASCT) in primary refractory Hodgkin Lymphoma (HL). From 1 October 1994 to 10 July 2015, 192 primary refractory HL patients were treated on sequential second line protocols. Event-free survival (EFS) and overall survival (OS) were calculated from the date of histological confirmation of refractory disease. Covariates were analysed for relationship with FI response and EFS. By intent-to-treat, the median EFS was 8·9 years and OS 10·4 years with 41% having positive post-salvage FI. On multivariate analysis, the presence of B symptoms and bulk ≥5 cm predicted for positive FI, with odds ratios of 2·15 and 2·03, respectively. For the 167 (87%) transplanted patients, 60% had a negative pre-ASCT FI. Median EFS and OS were not reached with at a median follow-up of 3·6 years in surviving patients. Both stage IV refractory disease and persistent FI abnormality pre- ASCT were associated with worse outcomes: 3-year EFS was 84%, 54% and 28% for zero, 1 and 2 risk factors, respectively (P < 0·001). Further studies are needed to validate our prognostic model and to determine optimal therapy for patients with multiple risk factors.

Treatment of relapsed and refractory Hodgkin Lymphoma

Despite the high first-line cure rates in patients with Hodgkin Lymphoma (HL) still 10%-20% of patients suffer from relapsed or refractory disease. High-dose chemotherapy (HDCT) followed by autologous stem cell transplant (ASCT) is standard of care for suitable patients with relapsed or refractory HL and allows for cure in approximately 50%. Due to the poor prognosis of high-risk patients even with HDCT and ASCT, consolidation strategies have been evaluated to improve the cure rates. For patients with recurrence after HDCT and ASCT, treatment is palliative in most cases. The anti-CD30 antibody-drug conjugate brentuximab vedotin (BV) has been shown to induce high response rates in these patients; however, durable responses were reported in a small percentage of patients only. For carefully selected patients with multiple relapses, dose-reduced allogeneic transplant (RICallo) is a potentially curative option. The role of RICallo will have to be re-evaluated in the era of anti-programmed death-1 (PD1) antibodies.

Hodgkin lymphoma: 2016 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Hodgkin lymphoma (HL) is an uncommon B-cell lymphoid malignancy affecting 9,050 new patients annually and representing approximately 11.2% of all lymphomas in the United States.

DIAGNOSIS

HL is composed of two distinct disease entities; the more commonly diagnosed classical HL and the rare nodular lymphocyte predominant HL. Nodular sclerosis, mixed cellularity, lymphocyte depletion, and lymphocyte-rich HL are subgroups under the designation of classical HL.

RISK STRATIFICATION

An accurate assessment of the stage of disease in patients with HL is critical for the selection of the appropriate therapy. Prognostic models that identify patients at low or high risk for recurrence, as well as the response to therapy as determined by positron emission tomography (PET) scan, are used to optimize therapy.

RISK-ADAPTED THERAPY

Initial therapy for HL patients is based on the histology of the disease, the anatomical stage and the presence of poor prognostic features. Patients with early stage disease are typically treated with combined modality strategies utilizing abbreviated courses of combination chemotherapy followed by involved-field radiation therapy, while those with advanced stage disease receive a longer course of chemotherapy often without radiation therapy. Management of relapsed/refractory disease: High-dose chemotherapy (HDCT) followed by an autologous stem cell transplant (ASCT) is the standard of care for most patients who relapse following initial therapy. For patients who fail HDCT with ASCT, brentuximab vedotin, PD-1 blockade, nonmyeloablative allogeneic transplant or participation in a clinical trial should be considered.

Current and future immunotherapeutic approaches in Hodgkin lymphoma

Hodgkin lymphoma (HL) has become a highly curable malignancy even in advanced stages when treated adequately. However, relapsed or refractory disease and treatment-related toxicity constitute a significant clinical challenge. Innovative approaches are thus needed to improve treatment of these mainly young patients. In HL lesions, very few malignant Hodgkin and Reed-Sternberg (HRS) cells are embedded in an immunosuppressive microenvironment of reactive cells. Novel approaches such as bispecific antibodies, antibody-drug conjugates, immune-checkpoint inhibitors or adoptive cellular therapies are currently being investigated with promising results in relapsed or refractory patients. Encouraging response rates and a favorable toxicity profile have recently been reported in early phase clinical trials with antibodies blocking the programed-death receptor 1 (PD1). This review will summarize the current clinical knowledge on mechanism, safety and efficacy of the different agents and discuss potential future strategies, which are partly already investigated within clinical trials.

Brentuximab vedotin in relapsed/refractory Hodgkin lymphoma: An updated review of published data from the named patient program

Brentuximab vedotin was available via named patient program (NPP) to patients with relapsed/refractory (R/R) Hodgkin lymphoma (HL) or systemic anaplastic large-cell lymphoma in ∼60 non-US/Canadian countries, before local approval. Published results were examined recently; through systematic literature review, we identified 12 new NPP publications. Most (10/12) publications included new NPP data describing 8 unique cohorts (N=480; all R/R HL) and new participating countries. Overall response rates were 58-80%, and complete remission rates were 10-40%. With median follow-up of 9.5-26 months, median progression-free survival was 5-10.5 months and median overall survival (OS) had not been reached in most cohorts; 1- and 2-year OS was 67-76% and 58-67%, respectively. Tolerability was as expected from previous reports. Despite intrinsic bias and heterogeneous cohorts, this update supports previous findings showing comparable efficacy and tolerability of brentuximab vedotin between real-world practice and phase 2 trial results in R/R HL.

A safety evaluation of brentuximab vedotin for the treatment of Hodgkin lymphoma

INTRODUCTION

Brentuximab vedotin is an anti-CD30 monoclonal antibody-drug conjugate approved for treating relapsed or refractory Hodgkin lymphoma. The pivotal trial demonstrated brentuximab vedotin's efficacy and manageable toxicity profile with peripheral neuropathy and neutropenia being the most common side effects. The phase I study of brentuximab vedotin combined with ABVD or AVD revealed its contraindication with bleomycin due to pulmonary toxicity. As trials continue to investigate the drug in frontline and relapsed settings, emerging safety data will further define brentuximab vedotin's role in managing Hodgkin lymphoma.

AREAS COVERED

This article reviews the current literature on brentuximab vedotin in Hodgkin lymphoma treatment, both as a single agent and in combination regimens. The review focuses on safety findings from clinical trials, expected adverse events, and rare serious toxicities.

EXPERT OPINION

Brentuximab vedotin is a breakthrough antibody-drug conjugate that may provide new options in earlier lines of therapy for Hodgkin lymphoma. Results from the ongoing phase III trial comparing ABVD to AVD + brentuximab vedotin will inform whether brentuximab vedotin adds benefit to frontline therapy over the current standard of care. The optimal duration of treatment and brentuximab vedotin's potential as an alternative to radiation in early stage disease still warrant investigation.

Autologous Stem Cell Mobilization in the Age of Plerixafor

BACKGROUND

Autologous stem cell transplantation remains important in the treatment of myeloma and relapsed lymphoma. Plerixafor has been shown to significantly enhance stem cell mobilization but is very expensive.

PATIENTS AND METHODS

We evaluated plerixafor use in the 3-year period after its approval in December 2008.

RESULTS

A total of 277 patients with myeloma and lymphoma had stem cell mobilization; 97.5% were successfully mobilized, including 41.5% who received plerixafor. Plerixafor was generally used for rescue after suboptimal granulocyte-colony stimulating factor (G-CSF) mobilization ("just in time") or for remobilization after an unsuccessful attempt with chemotherapy plus G-CSF. In addition, 10% of patients received planned G-CSF plus plerixafor because of high risk factors for inadequate collection. Rescue plerixafor was more effective in patients with myeloma than lymphoma as after 1 dose of plerixafor; 85% versus 55% collected a minimum number of stem cells (2 × 10E6 CD34 cells/kg) for 1 transplant and 51% versus 15% collected > 5 × 10E6 CD34 cells/kg. After transplantation, there were no significant differences in engraftment as a consequence of plerixafor use. Among all patients, there were less platelet transfusions in patients provided ≥ 3.5 × 10E6 CD34(+) cells/kg.

CONCLUSION

With the judicious use of plerixafor, nearly all patients can collect enough stem cells to proceed to transplantation. Further studies, including hematologic tolerance to posttransplantation therapy, are required to determine the cost-effectiveness of using plerixafor to convert adequate to more optimal mobilizers.

Recent advances in the management of Hodgkin lymphoma

Hodgkin lymphoma (HL) is a rare cancer of the immune system that typically affects lymph nodes and sometimes other organs. Although the majority of patients can be potentially cured with the use of multi-agent chemotherapy and radiotherapy, a proportion of them will relapse or develop resistant disease for which treatment options are limited. In recent years, new agents have been developed and tested in HL with encouraging results. Two classes of drugs stand out as highly active in advanced HL based on recent study results: antibody-drug conjugates and programmed death 1 inhibitors. Clinical trials in HL with these agents have been completed in the past several years and the results have recently become available. In this review, we discuss the recent advances in the management of HL with a focus on strategies to decrease toxicity and a review of the two drug classes that have the potential to change the landscape of treatment of this disease.

Patients with classical Hodgkin lymphoma experiencing disease progression after treatment with brentuximab vedotin have poor outcomes

BACKGROUND

Brentuximab vedotin (BV) is a key therapeutic agent for patients with relapsed/refractory classical Hodgkin lymphoma (cHL). The outcomes of patients experiencing disease progression after BV are poorly described.

PATIENTS AND METHODS

We reviewed our institutional database to identify patients with cHL treated with BV who were either refractory to treatment or experienced disease relapse. We collected clinicopathologic features, treatment details at progression and outcome.

RESULTS

One hundred patients met inclusion criteria, with a median age of 32 years (range 18-84) at progression after BV. The median number of treatments before BV was 3 (range 0-9); 71 had prior autologous stem cell transplant. The overall response rate (ORR) to BV was 57%, and the median duration of BV therapy was 3 months (range 1-25). After disease progression post-BV, the most common treatment strategies were investigational agents (n = 30), gemcitabine (n = 15) and bendamustine (n = 12). The cumulative ORR to therapy was 33% (complete response 15%). After a median follow-up of 25 months (range 1-74), the median progression-free (PFS) and overall survival (OS) were 3.5 and 25.2 months, respectively. In multivariate analysis, no factors analyzed were predictive of PFS; age at progression >45 years and serum albumin <40 g/l at disease progression were associated with increased risk of death. Among patients who achieved response to therapy, allogeneic stem cell transplantation was associated with a non-significant trend toward superior OS (P = 0.11).

CONCLUSIONS

Patients with BV-resistant cHL have poor outcomes. These data serve as a reference for newer agents active in BV-resistant disease.

Severe Acute Pulmonary Toxicity Associated with Brentuximab in a Patient with Refractory Hodgkin's Lymphoma

Acute pulmonary toxicity associated with brentuximab appears to be a rare but serious adverse effect that can be potentially fatal. We report the case of a twenty-nine-year-old female with Hodgkin's lymphoma who was treated with brentuximab and later presented with severe acute pulmonary toxicity; she improved after the discontinuation of brentuximab and administration of antibiotics and glucocorticoid therapy. Currently there is very little data in the literature in regard to the clinical manifestations and characteristics of patients taking brentuximab and the potential development of acute severe pulmonary toxicity, as well as the appropriate therapeutic approach, making this particular case of successful treatment and resolution unique.

Impact of Pretransplantation (18)F-Fluorodeoxyglucose-Positron Emission Tomography on Survival Outcomes after T Cell-Depleted Allogeneic Transplantation for Hodgkin Lymphoma

Pretransplant (18)F-fluorodeoxyglucose (FDG) positron emission tomography status is an important prognostic factor for outcomes after autologous stem cell transplantation (SCT) in Hodgkin lymphoma (HL), but its impact on outcomes after allogeneic SCT remains unclear. We retrospectively evaluated outcomes after T cell-depleted allogeneic SCT of 116 patients with nonprogressive HL according to pretransplant Deauville scores. Endpoints were overall survival (OS), progression-free survival (PFS), relapse rate (RR), and nonrelapse-related mortality (NRM). OS, PFS, and RR did not differ significantly between the Deauville 1 to 2 and Deauville 3 to 5 cohorts (OS: 77.5% versus 67.3%, P = .49; PFS: 59.4% versus 55.7%, P = .43; RR: 20.9% versus 22.6%, P = .28 at 4 years). Differences in PFS remained statistically nonsignificant when comparisons were made between Deauville 1 to 3 and Deauville 4 to 5 cohorts (60.9% versus 51.4%, P = .10), and RR remained very similar (21.5% versus 23.8%, P = .42). Multivariate analyses demonstrated trends toward significance for an effect of Deauville score on PFS (hazard ratio 1.82 for Deauville 4 to 5, P = .06) and for number of lines of prior therapy on OS (hazard ratio 2.34 for >5 lines, P = .10). The latter effect appeared to be driven by higher NRM rather than increased RR. Our findings suggest that Deauville score before allogeneic SCT in patients with nonprogressive HL has a relatively modest impact on survival outcomes in comparison with the impact in autologous SCT and that predictive values for the individual patient remain low, indicating that residual FDG-avid disease should not preclude allogeneic SCT. Furthermore, our findings bring into question the importance of attainment of metabolic complete response in this setting if it is at the expense of increasing NRM risk.

Emerging drugs for graft-versus-host disease

INTRODUCTION

Graft-versus-host disease (GVHD) leads to significant morbidity and mortality after allogeneic stem cell transplantation. While corticosteroids alone are adequate in some cases, they are often insufficient, leading to poor quality of life associated with the symptoms of disease, or mortality from infection and GVHD. Moreover, corticosteroids have significant side effects and often do not lead to durable responses. New therapies are needed to improve the development and progression of acute and chronic GVHD.

AREAS COVERED

We discuss the spectrum of emerging drugs for GVHD prevention and therapy. Cellular therapies will be briefly discussed. The available pre-clinical and clinical data regarding monoclonal antibodies, interleukin-2, alpha-1 antitrypsin, histone deacetylase inhibitors, tyrosine kinase inhibitors, and proteasome inhibitors will be reviewed.

EXPERT OPINION

Although therapies emerging for GVHD remain promising, most of these drugs are still in early phase clinical trials and require randomized comparisons before formal conclusions can be drawn. It is likely that in the near future some of these agents will show improvements in response when compared with corticosteroids alone. Although it is difficult to predict which of these agents will be most promising, alpha-1 antitrypsin, ruxolitinib and interleukin-2 have demonstrated encouraging results.

Autologous stem cell transplantation for patients aged 60 years or older with refractory or relapsed classical Hodgkin's lymphoma: a retrospective analysis from the French Society of Bone Marrow Transplantation and Cell Therapies (SFGM-TC)

This report retrospectively analyzed the outcome of 91 patients aged 60 years or older with refractory/relapsed (R/R) classical Hodgkin's lymphoma (cHL) who underwent autologous stem cell transplantation (ASCT) between 1992 and 2013 and were reported to the French Society of Bone Marrow Transplantation and Cell Therapies registry. The median age at transplant was 63 years. The majority of patients exhibited disease chemosensitivity to salvage treatment (57 complete responses, 30 partial responses, 1 progressive disease and 3 unknown). The most frequent conditioning regimen consisted of BCNU, cytarabine, etoposide, melphalan (BEAM) chemotherapy (93%). With a median follow-up of 54 months, 5-year estimates of overall survival (OS) and progression free survival (PFS) for the entire group were 67 and 54%, respectively. Despite the missing data, in univariate analysis, the number of salvage chemotherapy lines (1-2 versus ⩾3) significantly influenced the OS, unlike the other prognostic factors (stage III-IV at relapse, disease status before ASCT and negative positron emission tomography (PET) scan) encountered in younger patients. In spite of its limitations, this retrospective study with a long-term follow-up suggests that ASCT is a valid treatment option for chemosensitive R/R cHL in selected elderly patients, with an acceptable rate of toxicity.

Role of Maintenance Therapy after High-Dose Chemotherapy and Autologous Hematopoietic Cell Transplantation in Aggressive Lymphomas: A Systematic Review

Significant uncertainty exists in regard to the efficacy of maintenance therapy after high-dose chemotherapy (HDC) as well as autologous stem cell transplantation (ASCT) for the treatment of patients with aggressive lymphoma. A systematic review was performed to evaluate the effectiveness of post-ASCT maintenance therapy in patients with relapsed/refractory lymphoma. A comprehensive literature search yielded 4476 studies and a total of 42 studies (11 randomized controlled trials [RCT], 9 retrospective comparative studies, and 22 single-arm studies) were included in the systematic review. There was significant heterogeneity in study design, chemotherapeutic regimens, post-ASCT maintenance strategies, patient enrollment criteria, and study endpoints. Our findings suggest that post-ASCT maintenance immune-targeting strategies, including PD-1/PD-L1 blocking antibodies, rituximab, and brentuximab, may improve progression-free survival but not overall survival. Collectively, the results indicate a need for testing new strategies with well-designed and adequately powered RCTs to better address the role of post-ASCT maintenance in relapsed/refractory lymphomas.

Cyanobacterial Metabolite Calothrixins: Recent Advances in Synthesis and Biological Evaluation

The marine environment is host to unparalleled biological and chemical diversity, making it an attractive resource for the discovery of new therapeutics for a plethora of diseases. Compounds that are extracted from cyanobacteria are of special interest due to their unique structural scaffolds and capacity to produce potent pharmaceutical and biotechnological traits. Calothrixins A and B are two cyanobacterial metabolites with a structural assembly of quinoline, quinone, and indole pharmacophores. This review surveys recent advances in the synthesis and evaluation of the biological activities of calothrixins. Due to the low isolation yields from the marine source and the promise this scaffold holds for anticancer and antimicrobial drugs, organic and medicinal chemists around the world have embarked on developing efficient synthetic routes to produce calothrixins. Since the first review appeared in 2009, 11 novel syntheses of calothrixins have been published in the efforts to develop methods that contain fewer steps and higher-yielding reactions. Calothrixins have shown their potential as topoisomerase I poisons for their cytotoxicity in cancer. They have also been observed to target various aspects of RNA synthesis in bacteria. Further investigation into the exact mechanism for their bioactivity is still required for many of its analogs.

Targeting CD30 Using Brentuximab Vedotin in the Treatment of Hodgkin Lymphoma

The expression of CD30 receptors is one of the defining characteristics of the malignant Reed-Sternberg cells of Hodgkin lymphoma (HL). CD30 is rarely expressed by normal cells and is rapidly internalized, making it an ideal therapeutic target for monoclonal antibodies and for antibody-drug conjugates. Brentuximab vedotin is the first antibody-drug conjugate to be approved by regulatory agencies for the treatment of patients with relapsed HL, with a single-agent response rate of 75%. In this review article, we discuss the current and ongoing development of brentuximab vedotin in patients with relapsed and newly diagnosed HL.

Single or tandem autologous stem-cell transplantation for first-relapsed or refractory Hodgkin lymphoma: 10-year follow-up of the prospective H96 trial by the LYSA/SFGM-TC study group

We assessed the long-term results of autologous stem-cell transplantation for patients with first-relapsed or refractory Hodgkin lymphoma included in the prospective Lymphoma Study Association/Société Française de Greffe de Moelle H96 trial. This large multicenter phase II trial evaluated a risk-adapted strategy with single or tandem autologous stem-cell transplantation for 245 Hodgkin lymphoma patients. Poor-risk patients (n=150) had primary refractory Hodgkin lymphoma (n=77) or ≥2 risk factors at first relapse (n=73) and were eligible for tandem autologous stem-cell transplantation. Intermediate-risk patients (n=95) had one risk factor at first relapse and were eligible for single autologous stem-cell transplantation. With a median follow-up of 10.3 years, 10-year freedom from second failure and overall survival rates were, respectively: 64% (95% CI, 54% to 74%) and 70% (95% CI, 61% to 80%) for the intermediate-risk group, and 41% (95% CI, 33% to 49%) and 47% (95% CI, 39% to 55%) for the poor-risk group. Considering only patients who did not relapse after completing autologous stem-cell transplantation, the 15-year cumulative incidences of second primary malignancies were 24% for the 70 intermediate-risk patients and 2% for the 75 poor-risk ones. With long-term follow-up, the risk-adapted strategy remains appropriate. Tandem autologous stem-cell transplantation can still be considered an option for poor-risk patients, but integration of positron-emission tomography findings and new drugs may help to refine the need for a second autologous stem-cell transplant and possibly improve outcomes of patients with first-relapsed or refractory Hodgkin lymphoma.

Antibody-mediated delivery of therapeutics for cancer therapy

INTRODUCTION

Antibody-conjugated therapies (ACTs) combine the specificity of monoclonal antibodies to target cancer cells directly with highly potent payloads, often resulting in superior efficacy and/or reduced toxicity. This represents a new approach to the treatment of cancer. There have been highly promising clinical trial results using this approach with improvements in linker and payload technology. The breadth of current trials examining ACTs in haematological malignancies and solid tumours indicate the potential for clinical impact.

AREAS COVERED

This review will provide an overview of ACTs currently in clinical development as well as the principles of antibody delivery and types of payloads used, including cytotoxic drugs, radiolabelled isotopes, nanoparticle-based siRNA particles and immunotoxins.

EXPERT OPINION

The focus of much of the clinical activity in ACTs has, understandably, been on their use as a monotherapy or in combination with standard of care drugs. This will continue, as will the search for better targets, linkers and payloads. Increasingly, as these drugs enter routine clinical care, important questions will arise regarding how to optimise ACT treatment approaches, including investigation of resistance mechanisms, biomarker and patient selection strategies, understanding of the unique toxicities of these drugs, and combinatorial approaches with standard therapies as well as emerging therapeutic agents like immunotherapy.

Clinical Options in Relapsed or Refractory Hodgkin Lymphoma: An Updated Review

Hodgkin lymphoma (HL) is a potentially curable lymphoma, and modern therapy is expected to successfully cure more than 80% of the patients. Second-line salvage high-dose chemotherapy and autologous stem cell transplantation (auto-SCT) have an established role in the management of refractory and relapsed HL, leading to long-lasting responses in approximately 50% of relapsed patients and a minority of refractory patients. Patients progressing after intensive treatments, such as auto-SCT, have a very poor outcome. Allogeneic SCT represents the only strategy with a curative potential for these patients; however, its role is controversial. Based on recent knowledge of HL pathology, biology, and immunology, antibody-drug conjugates targeting CD30, small molecule inhibitors of cell signaling, and antibodies that inhibit immune checkpoints are currently explored. This review will discuss the clinical results regarding auto-SCT and allo-SCT as well as the current role of emerging new treatment strategies.

Salvage treatment for relapsed/refractory Hodgkin lymphoma: role of allografting, brentuximab vedotin and newer agents

INTRODUCTION

Second-line, salvage chemotherapy followed by high-dose chemotherapy and autologous stem cell transplantation (AUTO-SCT) is the standard of care for patients with relapsed/refractory (R/R) Hodgkin lymphoma (HL). Approximately 50% of patients relapse after AUTO-SCT and their prognosis is generally poor. Brentuximab Vedotin (BV) has demonstrated efficacy in this setting and allogeneic (ALLO)-SCT represents an option with curative potential in this subgroup of patients.

AREAS COVERED

A systematic review has been conducted to explore the actual knowledge on ALLO-SCT, BV and newer agents in R/R HL.

EXPERT OPINION

The introduction of BV in clinical practice has significantly improved the management of post-AUTO-SCT relapses and the drug can induce durable remissions in a subset of R/R HL. Allografting select patients has been used to improve clinical outcomes and recent case series have begun to explore BV as a potential 'bridge' to allo-SCT, even though the optimal timing of ALLO-SCT after BV response remains undetermined. However, reduced tumor burden at the time of ALLO-SCT is a key factor to decrease relapse risk. Based on the unique composition of the tumor, more recently new agents such as PD-1 inhibitors have been developed. The potential role of PD-1 inhibitors with ALLO-SCT remains to be explored.

Hodgkin lymphoma in children and adolescents: improving the therapeutic index

Hodgkin lymphoma (HL) is a highly curable form of childhood cancer, with estimated 5 year survival rates exceeding 98%. However, the establishment of a “standard of care” approach to its management is complicated by the recognition that long-term overall survival declines in part from delayed effects of therapy and that there continue to be subgroups of patients at risk for relapse for which prognostic criteria cannot adequately define. This challenge has resulted in the development of various strategies aimed at identifying the optimal balance between maintaining overall survival and avoidance of long-term morbidity of therapy, often representing strategies quite different from those used for adults with HL. More precise risk stratification and methods for assessing the chemosensitivity of HL through imaging studies and biomarkers are in evolution. Recent advances in the understanding of the biology of HL have led to the introduction of targeted therapies in both the frontline and relapsed settings. However, significant barriers exist in the development of new combination therapies, necessitating collaborative studies across pediatric HL research consortia and in conjunction with adult groups for the adolescent and young adult (AYA) population with HL.

Brentuximab: a major advance in treatment of CD30-positive malignancies

Antibody-directed therapies allow greater selectivity in targeting of tumor associated antigens and spare normal cells. Brentuximab vedotin is an anti-CD30 antibody–drug conjugate. It has demonstrated impressive activity in the treatment of refractory and or relapsed Hodgkin's lymphoma, anaplastic large cell lymphoma and other CD30+ lymphoid malignancies. Several ongoing trials are testing the potential use of brentuximab vedotin for treatment of various CD30+ and CD30- malignancies in the setting of high-risk untreated disease. It is being tested in combination with chemotherapy, and testing in combination with immune therapy is also planned. CD30 plays a pivotal role in immune regulation and is also an attractive new target for intervention in the setting of select auto-immune diseases, as well as graft versus host disease.

Hodgkin lymphoma in children and adolescents: improving the therapeutic index

Hodgkin lymphoma (HL) is a highly curable form of childhood cancer, with estimated 5 year survival rates exceeding 98%. However, the establishment of a “standard of care” approach to its management is complicated by the recognition that long-term overall survival declines in part from delayed effects of therapy and that there continue to be subgroups of patients at risk for relapse for which prognostic criteria cannot adequately define. This challenge has resulted in the development of various strategies aimed at identifying the optimal balance between maintaining overall survival and avoidance of long-term morbidity of therapy, often representing strategies quite different from those used for adults with HL. More precise risk stratification and methods for assessing the chemosensitivity of HL through imaging studies and biomarkers are in evolution. Recent advances in the understanding of the biology of HL have led to the introduction of targeted therapies in both the frontline and relapsed settings. However, significant barriers exist in the development of new combination therapies, necessitating collaborative studies across pediatric HL research consortia and in conjunction with adult groups for the adolescent and young adult (AYA) population with HL.

How I treat relapsed classical Hodgkin lymphoma after autologous stem cell transplant

Despite the success of standard front-line chemotherapy for classical Hodgkin lymphoma (cHL), a subset of these patients, particularly those with poor prognostic factors at diagnosis (including the presence of B symptoms, bulky disease, advanced stage, or extranodal disease), relapse. For those patients who relapse following autologous stem cell transplant (SCT), multiple treatment options are available, including single-agent chemotherapy, combination chemotherapy strategies, radiotherapy, the immunoconjugate brentuximab, checkpoint inhibitors nivolumab and pembrolizumab, lenalidomide, everolimus, or observation in selected patients. In patients with an available donor, allogeneic SCT may also be considered. With numerous treatment options available, we advocate for a tailored therapeutic approach for patients with relapsed cHL guided by patient-specific characteristics including age, comorbidities, sites of disease (nodal or organ), previous chemosensitivity, and goals of treatment (long-term disease control vs allogeneic SCT).

Strategies and Advancement in Antibody-Drug Conjugate Optimization for Targeted Cancer Therapeutics

Antibody-drug conjugates utilize the antibody as a delivery vehicle for highly potent cytotoxic molecules with specificity for tumor-associated antigens for cancer therapy. Critical parameters that govern successful antibody-drug conjugate development for clinical use include the selection of the tumor target antigen, the antibody against the target, the cytotoxic molecule, the linker bridging the cytotoxic molecule and the antibody, and the conjugation chemistry used for the attachment of the cytotoxic molecule to the antibody. Advancements in these core antibody-drug conjugate technology are reflected by recent approval of Adectris(®) (anti-CD30-drug conjugate) and Kadcyla(®) (anti-HER2 drug conjugate). The potential approval of an anti-CD22 conjugate and promising new clinical data for anti-CD19 and anti-CD33 conjugates are additional advancements. Enrichment of antibody-drug conjugates with newly developed potent cytotoxic molecules and linkers are also in the pipeline for various tumor targets. However, the complexity of antibody-drug conjugate components, conjugation methods, and off-target toxicities still pose challenges for the strategic design of antibody-drug conjugates to achieve their fullest therapeutic potential. This review will discuss the emergence of clinical antibody-drug conjugates, current trends in optimization strategies, and recent study results for antibody-drug conjugates that have incorporated the latest optimization strategies. Future challenges and perspectives toward making antibody-drug conjugates more amendable for broader disease indications are also discussed.

Immuno-PET Imaging of CD30-Positive Lymphoma Using 89Zr-Desferrioxamine-Labeled CD30-Specific AC-10 Antibody

The CD30-specific antibody-drug conjugate, brentuximab vedotin, is approved for the treatment of relapsed, refractory Hodgkin lymphomas and systemic anaplastic large T-cell lymphomas. Multiple ongoing clinical trials are investigating brentuximab vedotin efficacy in other CD30-positive hematologic malignancies. Because CD30 expression varies among different types of lymphoma and can also change during the course of treatment, companion diagnostic imaging of CD30 could be a valuable tool in optimizing patient-specific brentuximab vedotin treatment regimens.

METHODS

The mouse antihuman CD30 antibody AC-10 was radiolabeled with the positron-emitting radionuclide (89)Zr. The stability and specificity of (89)Zr-desferrioxamine (DFO)-labeled CD30-specific AC-10 antibody ((89)Zr-DFO-AC-10) was evaluated in vitro. The pharmacokinetics of (89)Zr-DFO-AC-10 was studied in BALB/c nude mice bearing subcutaneous human Karpas 299 tumors (CD30-positive model) or A-431 tumors (CD30-negative model) using PET/CT imaging, biodistribution studies, and autoradiography.

RESULTS

AC-10 was conjugated with a DFO B chelator and radiolabeled with (89)Zr to give formulated (89)Zr-DFO-AC-10 with a radiochemical yield of 80%, radiochemical purity greater than 99%, and specific activity of 111-148 MBq/mg. (89)Zr-DFO-AC-10 was stable in mouse and human sera and preserved the immunoreactivity toward CD30. Biodistribution data showed the highest tissue accumulation of (89)Zr-DFO-AC-10 in CD30-positive tumors, with 37.9% ± 8.2% injected activity per gram of tissue at 72 h after injection, whereas uptake in CD30-negative tumors was 11.0% ± 0.4%. The specificity of (89)Zr-DFO-AC-10 binding to CD30 in vivo was confirmed by blocking studies. Time-activity curves showed that between 24 and 144 h after injection, tumor-to-muscle ratios increased from 18.9 to 51.8 in the CD30-positive model and from 4.8 to 8.7 in the CD30-negative model. Tumor-to-blood ratios also increased, from 3.2 to 13.6 and from 1 to 2 in the CD30-positive and -negative models, respectively.

CONCLUSION

Our results demonstrate that for measuring CD30 expression, (89)Zr-DFO-AC-10 is a sensitive PET agent with high tumor-to-normal-tissue contrast. (89)Zr-DFO-AC-10 is a promising CD30-imaging radiotracer for clinical translation in patients with various lymphomas and other diseases.

CAR-T Cell Therapy for Lymphoma

Lymphomas arise from clonal expansions of B, T, or NK cells at different stages of differentiation. Because they occur in the immunocyte-rich lymphoid tissues, they are easily accessible to antibodies and cell-based immunotherapy. Expressing chimeric antigen receptors (CARs) on T cells is a means of combining the antigen-binding site of a monoclonal antibody with the activating machinery of a T cell, enabling antigen recognition independent of major histocompatibility complex restriction, while retaining the desirable antitumor properties of a T cell. Here, we discuss the basic design of CARs and their potential advantages and disadvantages over other immune therapies for lymphomas. We review current clinical trials in the field and consider strategies to improve the in vivo function and safety of immune cells expressing CARs. The ultimate driver of CAR development and implementation for lymphoma will be the demonstration of their ability to safely and cost-effectively cure these malignancies.

A review of monoclonal antibody therapies in lymphoma

Monoclonal antibodies (moAb) represent a novel way of delivering therapy through specific target antigens expressed on lymphoma cells and minimizes the collateral damage that is common with conventional chemotherapy. The paradigm of this approach is the targeting of CD20 by rituximab. Since its FDA approval in 1997, rituximab has become the standard of care in almost every line of therapy in most B-cell lymphomas. This review will briefly highlight some of the key rituximab trials while looking more closely at the evidence that is bringing other antibodies, including next generation anti-CD20 moAbs, and anti-CD30 moAbs, among others to the forefront of lymphoma therapy.

Recent advances in antibody-based therapies for Hodgkin Lymphoma

Although a poster child for the development and refinement of multi-modal multi-agent therapeutic strategies, Hodgkin Lymphoma has, until recently, lagged behind other lymphomas in terms of the use of therapeutic monoclonal antibodies. This situation has now changed dramatically, with the rapid emergence both of a toxin-conjugated tumour-selective anti-CD30 antibody, and of antibodies targeting immunological checkpoints, most notably PD-1 (also termed PDCD1). The former provides an efficient targeting vehicle for delivery of a potent synthetic anti-mitotic drug, with ultimate efficacy independent of immunological activity. The latter are members of a class of drugs representing a new paradigm in immune-oncological therapies that are designed to enhance pre-existent anti-tumour T cell activities. The role of both in the overall treatment pathway will continue to evolve over coming years. Hodgkin Lymphoma has once again become emblematic of the major trend shifts in cancer therapy.

Role of cytotoxic therapy with hematopoietic cell transplantation in the treatment of Hodgkin lymphoma: guidelines from the American Society for Blood and Marrow Transplantation

The role of hematopoietic cell transplantation (HCT) in the therapy of Hodgkin lymphoma (HL) in pediatric and adult patients is reviewed and critically evaluated in this systematic evidence-based review. Specific criteria were used for searching the published literature and for grading the quality and strength of the evidence and the strength of the treatment recommendations. Treatment recommendations based on the evidence are included and were reached unanimously by a panel of HL experts. Both autologous and allogeneic HCT offer a survival benefit in selected patients with advanced or relapsed HL and are currently part of standard clinical care. Relapse remains a significant cause of failure after both transplant approaches, and strategies to decrease the risk of relapse remain an important area of investigation.