Phase I/II Study of an Anti-CD30 Monoclonal Antibody (MDX-060) in Hodgkin's Lymphoma and Anaplastic Large-Cell Lymphoma

Microtubule inhibitor-based antibody-drug conjugates for cancer therapy

The specificity of monoclonal antibodies represents a potential therapeutic advantage, but their use as single agents in oncology has proven limited to date. The development of antibody-drug conjugates (ADCs) takes advantage of the specificity of the monoclonal antibody and potent cytotoxic effect of chemotherapy, leading to enhanced cytotoxicity in target cells and limiting toxicity to normal tissue. Microtubules represent a validated oncologic target in a range of tumor types, with a number of anti-microtubule targeting cytotoxic drugs approved for cancer use. The systemic use of potent microtubule-binding agents is limited by their effects in normal cells, which leads to toxicity including myelosuppression and peripheral neuropathy. Linking these agents to monoclonal antibodies may limit toxicity to normal tissues and increase drug concentration in target tissues, also allowing the use of more potent agents which would be too toxic to administer in their unbound form. Two such ADCs have been approved for clinical use and many others are in development. Here we review the characteristics of each of the ADC components that have led to efficacious therapies and discuss some of the tubulin inhibitor-based ADCs in development for cancer therapy.

The development of immunoconjugates for targeted cancer therapy

Immunoconjugates are specific, highly effective, minimally toxic anticancer therapies that are beginning to show promise in the clinic. Immunoconjugates consist of three separate components: an antibody that binds to a cancer cell antigen with high specificity, an effector molecule that has a high capacity to kill the cancer cell, and a linker that will ensure the effector does not separate from the antibody during transit and will reliably release the effector to the cancer cell or tumour stroma. The high affinity antibody-antigen interaction allows specific and selective delivery of a range of effectors, including pharmacologic agents, radioisotopes, and toxins, to cancer cells. Some anticancer molecules are not well tolerated when administered systemically owing to unacceptable toxicity to the host. However, this limitation can be overcome through the linking of such cytotoxins to specific antibodies, which mask the toxic effects of the drug until it reaches its target. Conversely, many unconjugated antibodies are highly specific for a cancer target, but have low therapeutic potential and can be repurposed as delivery vehicles for highly potent effectors. In this Review, we summarize the successes and shortcomings of immunoconjugates, and discuss the future potential for the development of these therapies.

The development of potential antibody-based therapies for myeloma

With optimal target antigen selection antibody-based therapeutics can be very effective agents for hematologic malignancies, but none have yet been approved for myeloma. Rituximab and brentuximab vedotin are examples of success for the naked antibody and antibody-drug conjugate classes, respectively. Plasma cell myeloma is an attractive disease for antibody-based targeting due to target cell accessibility and the complementary mechanism of action with approved therapies. Initial antibodies tested in myeloma were disappointing. However, recent results from targeting well-characterized antigens have been more encouraging. In particular, the CD38 and CD138 targeted therapies are showing single-agent activity in early phase clinical trials. Here we will review the development pipeline for naked antibodies and antibody-drug conjugates for myeloma. There is clear clinical need for new treatments, as myeloma inevitably becomes refractory to standard agents. The full impact is yet to be established, but we are optimistic that the first FDA-approved antibody therapeutic(s) for this disease will emerge in the near future.

Therapeutic options in relapsed or refractory peripheral T-cell lymphoma

Peripheral T-cell lymphoma (PTCL) represents a relatively rare group of heterogeneous non-Hodgkin lymphomas with a very poor prognosis. Current therapies, based on historical regimens for aggressive B-cell lymphomas, have resulted in insufficient patient outcomes. The majority of patients relapse rapidly, and current 5-year overall survival rates are only 10-30%. It is evident that new approaches to treat patients with PTCL are required. In recent years, prospective studies in PTCL have been initiated, mainly in patients with relapsed/refractory disease. In some of these, selected histologic subtypes have been evaluated in detail. As a consequence, numerous new therapies have been developed and shown activity in PTCL, including: agents targeting the immune system (e.g. brentuximab vedotin, alemtuzumab, lenalidomide); histone deacetylase inhibitors (romidepsin, belinostat); antifolates (pralatrexate); fusion proteins (denileukin diftitox); nucleoside analogs (pentostatin, gemcitabine); and other agents (e.g. alisertib, plitidepsin, bendamustine, bortezomib). A variety of interesting novel combinations is also emerging. It is hoped that these innovative approaches, coupled with a greater understanding of the clinicopathologic features, pathogenesis, molecular biology, and natural history of PTCL will advance the field and improve outcomes in this challenging group of diseases. This review summarizes the currently available clinical evidence on the various approaches to treating relapsed/refractory PTCL, including the role of stem cell transplantation, with an emphasis on potential new drug therapies.

Antibodies and antibody-drug conjugates in the treatment of Hodgkin lymphoma

Hodgkin lymphoma (HL) is a B cell-derived lymphoid malignancy most often affecting young adults. More than 80% of HL patients achieve long-term remission after appropriate first-line treatment consisting of multiagent chemotherapy and/or radiotherapy (RT). In addition, approximately 50% of patients with disease recurrence remain relapse-free after salvage therapy with high-dose chemotherapy followed by autologous stem cell transplantation (ASCT). However, patients with multiple relapses are mostly in a palliative situation, and novel drugs for this patient group are needed. Furthermore, novel less toxic but equally effective first-line and second-line approaches are required as therapy-related late sequelae represent a relevant cause of morbidity and mortality in HL survivors. Several antibodies and antibody-drug conjugates (ADC) targeting CD30 and CD20 have recently been evaluated in HL. Excellent response rates in heavily pretreated patients were observed with the ADC brentuximab vedotin directed against CD30. Thus, ongoing trials investigate brentuximab vedotin in different additional indications. One example is the first-line treatment of advanced HL where the drug is currently being evaluated in combination with variants of the first-line protocols ABVD (adriamycin, bleomycin, vinblastine, dacarbazine) and escalated BEACOPP (bleomycin, etoposide, adriamycin, cyclophosphamide, vincristine, procarbazine, prednisone). Anti-CD20 antibodies given either as single agent or in combination with conventional chemotherapy have also been investigated and still undergo investigation in prospective studies including HL patients. This article reviews the available data on treatment approaches including antibodies and ADC in HL patients.

An update on emerging drugs for Hodgkin lymphoma

INTRODUCTION

Most patients with Hodgkin lymphoma (HL) are cured with modern combined modality first-line treatments. Even ~ 50% of patients with relapsed/refractory HL can be cured with high-dose chemotherapy (HDCT) and autologous stem cell transplantation. However, chemotherapy and radiotherapy cause significant acute and long-term side effects and patients relapsing after HDCT have a dismal prognosis. New drugs are therefore needed to reduce the toxicity of first-line treatments and to increase the efficacy of relapse treatments. Moreover, new drugs are needed for the treatment of older patients with HL because results with current treatments are disappointing.

AREAS COVERED

This article discusses promising new drugs for the treatment of classical HL that have been evaluated in the last years. There is a focus on the antibody drug conjugate brentuximab vedotin and its potential for the future treatment of HL. Moreover, data on the histone deacetylase inhibitors panobinostat and mocetinostat, the mammalian target of rapamycin inhibitor everolimus, the Janus kinase 2 inhibitor SB1518 and the immunomodulatory agent lenalidomide are summarized.

EXPERT OPINION

Besides improving the prognosis of relapsed patients, new drugs should be used to replace the most toxic compounds in first-line therapy to reduce acute and long-term toxicities of the treatment.

CD30 in systemic mastocytosis

CD30 is a transmembrane receptor, normally not expressed by mast cells, which regulates proliferation/apoptosis and antibody responses. Aberrant expression of CD30 by mastocytosis mast cells and interaction with its ligand CD30L (CD153) appears to play an important role in the pathogenesis and clinical presentation of systemic mastocytosis. This article highlights the expression profile and role of CD30 and CD30L in physiologic and pathologic conditions, the applicability of CD30 as a marker for systemic mastocytosis, the consequences of mast cell-expressed CD30, and the possibility of future anti-CD30 based cytoreductive therapies.

Antibody-drug conjugates: an emerging concept in cancer therapy

Traditional cancer chemotherapy is often accompanied by systemic toxicity to the patient. Monoclonal antibodies against antigens on cancer cells offer an alternative tumor-selective treatment approach. However, most monoclonal antibodies are not sufficiently potent to be therapeutically active on their own. Antibody-drug conjugates (ADCs) use antibodies to deliver a potent cytotoxic compound selectively to tumor cells, thus improving the therapeutic index of chemotherapeutic agents. The recent approval of two ADCs, brentuximab vedotin and ado-trastuzumab emtansine, for cancer treatment has spurred tremendous research interest in this field. This Review touches upon the early efforts in the field, and describes how the lessons learned from the first-generation ADCs have led to improvements in every aspect of this technology, i.e., the antibody, the cytotoxic compound, and the linker connecting them, leading to the current successes. The design of ADCs currently in clinical development, and results from mechanistic studies and preclinical and clinical evaluation are discussed. Emerging technologies that seek to further advance this exciting area of research are also discussed.

Targeted gene delivery with noncovalent electrostatic conjugates of sgc-8c aptamer and polyethylenimine

BACKGROUND

Several strategies have been shown to improve the transfection efficiency of polyethylenimine (PEI) as a nonviral gene delivery vector. In the present study, a nucleic acid aptamer specific for protein tyrosine kinase 7 (PTK7) surface marker, sgc-8c, was conjugated electrostatically to pre-formed 10-kDa PEI/plasmid DNA polyplexes, and the ability of the conjugate to transfer genetic material was evaluated in MOLT-4 human acute lymphoblastic leukemia T-cells, which express PTK7 on their surface.

METHODS

Polyplexes (plasmid DNA-vector conjugates), prepared using PEI-sgc-8c conjugate and pCMVLuc as a reporter gene, were characterized in terms of particle size, surface charge and the extent of DNA condensation. Polyplexes were also evaluated for cytotoxicity using the MTS colorimetric assay, as well as for transfection efficiency in MOLT-4 cells, and compared with the results obtained in U266 cells, which lack cell surface PTK7.

RESULTS

Relative to pDNA/PEI, the size of pDNA/PEI/sgc-8c aptamer polyplexes increased with decreasing zeta potential. In MOLT-4 cells, pDNA/PEI/sgc-8c aptamer polyplexes exhibited an almost six- to eight-fold increase in transfection efficiency compared to that of pDNA/PEI polyplex, indicating that conjugation of sgc-8c aptamer to pre-formed 10-kDa PEI/plasmid DNA polyplexes achieved effective targeting without covalent attachment, whereas receptor-mediated conducted transfection was confirmed by performing a competitive transfection experiment and a cellular uptake study.

CONCLUSIONS

The results of the present study provide an example of the usefulness of a nucleic acid aptamer in the form of noncovalent, electrostatic conjugates as an approach for enhancing the transfection efficiency of a polycation vector such as PEI without significant induced cytotoxicity.

Customized targeted therapy in Hodgkin lymphoma: hype or hope?

Although most patients with Hodgkin lymphoma (HL) are cured with primary therapy, patients with primary refractory disease or relapse after initial treatment have poor outcomes and represent an unmet medical need. Recent advances in unraveling the biology of HL have yielded a plethora of novel targeted therapies. This review provides an overview of the data behind the hype generated by these advances and addresses the question of whether or not clinically these targeted therapies offer hope for patients with HL.

Molecular genetics of peripheral T-cell lymphomas

Peripheral T-cell lymphomas (PTCL) are rare neoplasms that in most instances respond poorly to conventional chemotherapies. Four varieties--PTCL not otherwise specified (NOS), angioimmunoblastic T-cell lymphoma (AITL), ALK+ anaplastic T-cell lymphoma (ALCL), and ALK- ALCL--account for about 60 % of them. Their classification is difficult because of the wide spectrum of morphologic features and the lack of robust immunohistochemical markers. Thus, high-throughput technologies can importantly contribute to their better understanding. In particular, gene expression profiling has cleared the borders among PTCL/NOS, ALK- ALCL and AITL. In fact, gene signatures have been developed even from formalin-fixed paraffin-embedded tissue samples that definitely distinguish one tumor from the other(s). This has important practical implications: for instance on routine diagnostics PTCL/NOS expressing CD30 can be easily confused with ALK- ALCL, but has a much worse prognosis. Therefore, the clear-cut distinction between the two conditions is pivotal to understand the results of ongoing trials with Brentuximab Vedotin, targeting the CD30 molecule. Besides improving the diagnosis, molecular studies have provided the rationale for the usage of novel drugs in the setting of PTCLs, such as ALK inhibitors in ALK+ ALCL, anti-angiogenetic drugs in AITL, and tyrosine kinase inhibitors in PTCL/NOS and ALK+ and ALK- ALCLs.

Managing Hodgkin lymphoma relapsing after autologous hematopoietic cell transplantation: a not-so-good cancer after all!

Hodgkin lymphoma (HL) relapsing after an autologous hematopoietic cell transplant (HCT) poses a therapeutic challenge. In this setting, salvage chemotherapy (for example, gemcitabine-based, ifosfamide-containing and others) or immunotherapy (for example, brentuximab vedotin) is essential as a bridging-cytoreduction strategy to an allogeneic HCT. Myeloablative allogeneic hematopoietic cell transplantation in relapsed HL is associated with high rates of non-relapse mortality. In carefully selected patients with chemosensitive disease, allografting following lower-intensity conditioning regimens can provide durable disease control rates of about 25-35%. Promising early results with haploidentical and umbilical cord transplantation are noteworthy and are expanding this procedure to patients for whom HLA-matched related or unrelated donors are not available. Unfortunately, a significant number of HL patients relapsing after an autologous HCT are not candidates for allografting because of the presence of resistant disease, donor unavailability or comorbidities. Brentuximab vedotin is approved for HL relapsing after a prior autograft. Rituximab and bendamustine are also active in this setting, albeit with short durations of remission. Histone deacetylase inhibitors (for example, panobinostat, mocetinostat), mTOR inhibitors (for example, everolimus) and immunomodulatory agents (lenalidomide) have shown activity in phase II trials, but currently are not approved for this indication. Second autologous HCT are rarely performed but this approach should not be considered standard practice at this time. The need for effective agents for post autograft failures of HL largely remains unmet. Continuous efforts to ensure early referral of such patients for allogeneic HCT or investigational therapies are the key to improving outcomes of this not-so-good lymphoma.

Targeted therapy for Hodgkin lymphoma and systemic anaplastic large cell lymphoma: focus on brentuximab vedotin

Despite the relative success of chemotherapy for Hodgkin lymphoma (HL) and systemic anaplastic large cell lymphoma (ALCL), novel therapeutic agents are needed for refractory or relapsed patients. Targeted immunotherapy has emerged as a novel treatment option for these patients. Although unconjugated anti-cluster of differentiation (CD)30 antibodies showed minimal antitumor activity in early clinical trials, development of antibody–drug conjugates (ADCs) appears promising. Brentuximab vedotin is an ADC composed of an anti-CD30 antibody linked to a potent microtubule-disrupting agent monomethyl auristatin E (MMAE). It has the ability to target CD30-positive tumor cells and, once bound to CD30, brentuximab vedotin is internalized and MMAE is released to induce cell cycle arrest and apoptosis. In two Phase II trials, objective response was reported in 75% and 86% of patients with refractory or relapsed HL and systemic ALCL, respectively, with an acceptable toxicity profile. Based on these studies, the US Food and Drug Administration (FDA) granted accelerated approval of brentuximab vedotin in August 2011 for the treatment of refractory and relapsed HL and ALCL. We review the key characteristics of brentuximab vedotin, clinical data supporting its therapeutic efficacy, and current ongoing trials to explore its utility in other CD30-positive malignancies.

Evolution of clinical trial design in early drug development: systematic review of expansion cohort use in single-agent phase I cancer trials

PURPOSE

To evaluate the use and objectives of expansion cohorts in phase I cancer trials and to explore trial characteristics associated with their use.

METHODS

We performed a systematic review of MEDLINE and EMBASE, limiting studies to single-agent phase I trials recruiting adults and published after 2006. Eligibility assessment and data extraction were performed by two reviewers. Data were assessed descriptively, and associations were tested by univariable and multivariable logistic regression.

RESULTS

We identified 611 unique phase I cancer trials, of which 149 (24%) included an expansion cohort. The trials were significantly more likely to use an expansion cohort if they were published more recently, were multicenter, or evaluated a noncytotoxic agent. Objectives of the expansion cohort were reported in 74% of trials. In these trials, safety (80%), efficacy (45%), pharmacokinetics (28%), pharmacodynamics (23%), and patient enrichment (14%) were cited as objectives. Among expansion cohorts with safety objectives, the recommended phase II dose was modified in 13% and new toxicities were described in 54% of trials. Among trials aimed at assessing efficacy, only 11% demonstrated antitumor activity assessed by response criteria that was not previously observed during dose escalation.

CONCLUSION

The utilization of expansion cohorts has increased with time. Safety and efficacy are common objectives, but 26% fail to report explicit aims. Expansion cohorts may provide useful supplementary data for phase I trials, particularly with regard to toxicity and definition of recommended dose for phase II studies.

New drugs and targeted treatments in Hodgkin's lymphoma

New drugs are being developed in recent years that may change the handling of relapsed and refractory Hodgkin's lymphoma patients. Brentuximab vedotin treatment has already been approved by the FDA; and other drugs are promising, such as histone deacetylase inhibitors, bendamustine, lenalidomide and m-TOR inhibitors.

Developments in the immunophenotypic analysis of haematological malignancies

Immunophenotyping is the method by which antibodies are used to detect cellular antigens in clinical samples. Although the major role is in the diagnosis and classification of haematological malignancies, applications have expanded over the past decade. Immunophenotyping is now used extensively for disease staging and monitoring, to detect surrogate markers of genetic aberrations, to identify potential immuno-therapeutic targets and to aid prognostic prediction. This expansion in applications has resulted from developments in antibodies, methodology, automation and data handling. In this review we describe recent advances in both the technology and applications for the analysis of haematological malignancies. We highlight the importance of the expanding repertoire of testing capability for diagnostic, prognostic and therapeutic applications. The impact and significance of immunophenotyping in the assessment of haematological neoplasms are evident.

The anti-CD80 primatized monoclonal antibody, galiximab, is well-tolerated but has limited activity in relapsed Hodgkin lymphoma: Cancer and Leukemia Group B 50602 (Alliance)

Relapsed Hodgkin lymphoma remains a clinical challenge, with few non-cytotoxic treatment options. CD80 is a surface antigen that normally functions as a co-stimulatory molecule but is aberrantly and uniformly expressed on Reed-Sternberg cells. Galiximab is a primatized monoclonal antibody against CD80, with a favorable toxicity profile demonstrated in other lymphomas. Cancer and Leukemia Group B (CALGB) 50602 (Alliance) tested single-agent galiximab in a highly refractory group of patients with Hodgkin lymphoma (median 3 prior regimens, 83% failing after prior stem cell transplant) to determine the efficacy. The overall response rate was 10.3% and the median progression-free survival was 1.6 months. Galiximab was well-tolerated, with minimal grade 3 or 4 toxicities. Despite this preclinical rationale, single-agent galiximab had limited activity in heavily pretreated Hodgkin lymphoma.

Treatment strategies for peripheral T-cell lymphomas

Peripheral T-cell lymphomas (PTCL) are a heterogeneous group of clinically aggressive diseases historically associated with inferior outcomes using conventional lymphoma therapies. Aggressive first line therapy and consolidation with autologous stem cell transplantation has led to improved survival, but the majority of patients either fails to respond to therapy or are not transplant candidates. Novel approaches have included new classes of drug and biological agents, including antifolates, immunoconjugates, histone deacetylase (HDAC) inhibitors, monoclonal antibodies, and signal transduction inhibitors. Molecular profiling has led to identification of relevant pathways for future novel approaches.

New strategies in Hodgkin lymphoma: better risk profiling and novel treatments

Recent advances in Hodgkin lymphoma research are expected to prelude a promising new treatment era for patients and their treating physicians. Scientific investigations over the last few years have provided new insights into risk stratification, and, simultaneously, a plethora of novel targeted therapies are emerging for patients with relapsed and refractory disease. These novel therapies will be tested primarily in high-risk patients because 75% of the patients are cured with conventional therapies. The challenges, as Hodgkin lymphoma therapy moves forward, will be using these biologic insights to identify the patients who may benefit earlier in treatment from these novel agents, and tailoring the therapy to the tumor biology of the patient. These dual aims are intertwined; as our therapeutic arsenal increases, these biologic determinants of risk may themselves inform the design of therapies and the choice of treatments for high-risk patients.

Recent new drug approvals, part 2: drugs undergoing active clinical studies in children

The objective of this 2-part review is to provide information about drugs that have been recently approved by the US Food and Drug Administration. Part 1 reviewed recently approved drugs with pediatric indications. Part 2 reviews drugs recently approved only in adults and have published or ongoing studies in children.

Brentuximab vedotin and crizotinib in anaplastic large-cell lymphoma

Systemic anaplastic large-cell lymphoma (ALCL) is a rare, mature T-cell non-Hodgkin lymphoma. Anaplastic large-cell lymphoma cells express the surface antigen CD30, and more than half express the anaplastic lymphoma kinase (ALK) protein. These 2 proteins provide unique therapeutic targets in ALCL. Remission rates in ALCL with combination chemotherapy are approximately 80%, but relapse after first-line therapy is common. Brentuximab vedotin is a US Food and Drug Administration-approved, antibody-drug conjugate that combines an anti-CD30 antibody with monomethylauristatin E, a potent antimicrotubule agent. Response rates to brentuximab vedotin in patients with relapsed/refractory ALK and ALK ALCL have exceeded 80% with frequent complete responses and a median duration of response greater than 1 year. Brentuximab vedotin in combination with chemotherapy is being explored as a first-line therapy in ALCL. Crizotinib is an inhibitor of ALK tyrosine kinase that has been approved for the treatment of ALK non-small cell lung cancer. Successful treatment of ALK ALCL with crizotinib has been reported in pediatric patients and small case series leading to ongoing trials in relapsed/refractory ALCL. Brentuximab vedotin and crizotinib represent major advances in the treatment of ALK and ALK ALCL and will likely result in marked improvement in prognosis for this subset of aggressive lymphomas.

Brentuximab Vedotin in CD30+ Lymphomas

Monoclonal antibodies (mAb) have become an effective treatment strategy for hematologic malignancies. CD30 is a rational target for therapy due to its limited expression on normal tissues and the strong and uniform expression on malignant cells in classical Hodgkin’s lymphoma (cHL) and anaplastic large-cell lymphoma (ALCL). Brentuximab vedotin, an anti-CD30 antibody-drug conjugate, utilizes the targeting properties of mAb to deliver a cytotoxic agent inside the malignant cell. Brentuximab vedotin has significant clinical activity in patients with relapsed or refractory cHL and relapsed or refractory ALCL, and has the potential to represent a significant advance in modern oncology.

Antibody-drug conjugates in hematologic malignancies

Antibody-drug conjugates (ADCs) are agents composed of a monoclonal antibody linked to cytotoxic molecules. By specifically delivering cytotoxic agents to cells expressing surface antigens of interest, ADC technology allows for the targeted use of highly toxic agents resulting in increased efficacy against malignant cells and decreased damage to normal tissue. Effector agents can be small molecules, radioisotopes, proteins, or bacterially derived toxins. Over the past several decades, ADCs have been evaluated in a variety of preclinical models of hematologic malignancies, as well as early-phase clinical trials with limited success. More recently, advancements in linkage technology, improvements in cytotoxin selection, and use of smaller conjugates containing partial rather than complete antibodies have drastically improved the potential clinical value of ADCs. In the future, ADC technology may be used to restore tumor suppressor activity, target the microenvironment, or replace nonfunctional enzymes. In this review we will discuss select ADCs in various stages of development for use in hematologic malignancies including lymphoma, multiple myeloma, and leukemia.

New molecular insights into peripheral T cell lymphomas

Peripheral T cell lymphomas (PTCLs) are heterogeneous neoplasms and represent about 12% of all lymphoid malignancies. They are often regarded as "orphan diseases," a designation that does not reflect their real incidence but rather signifies the difficulties encountered in their classification, diagnosis, and treatment. Here we revise the current understanding of the pathobiological characteristics of the most common nodal PTCLs by focusing on the contribution given by high-throughput technologies and the identification of potential therapeutic targets proposed by translational studies.

Brentuximab vedotin in Hodgkin's lymphoma

INTRODUCTION

Monoclonal antibodies (mAbs) directed against antigens expressed by tumor cells have become an effective therapeutic option in hematologic malignancies. Antibody-drug conjugates (ADC) utilize the targeting properties of mAbs to deliver cytotoxic agents inside the malignant cell. Brentuximab vedotin is a CD30-specific ADC with significant clinical activity in Hodgkin's lymphoma (HL).

AREAS COVERED

CD30 is an ideal target for therapy due to its limited expression on normal tissues and the strong and uniform expression on malignant cells in classical Hodgkin's lymphoma (cHL). Early studies using unconjugated CD30 mAbs have demonstrated lack of objective responses in patients with recurrent cHL. Brentuximab vedotin is an ADC with significant clinical activity in patients with HL. Here, the authors review the biology of brentuximab vedotin, summarize available clinical data and discuss future treatment strategies.

EXPERT OPINION

Brentuximab vedotin is a well-tolerated and highly active drug in patients with relapsed cHL. This novel agent has the potential to be incorporated in the standard management of the disease with significant therapeutic impact.

Safety and efficacy of brentuximab vedotin in patients with Hodgkin lymphoma or systemic anaplastic large cell lymphoma

Antibody-based immunotherapy has become an integral part of cancer therapeutics. However, monoclonal antibodies have their limitations as identifying an antigen selectively expressed on malignant cells and developing a high-affinity antibody may not by itself alter tumor growth. This is illustrated in the case of CD30; CD30 epitomizes many properties of an ideal pharmacologic target such as high expression on malignant cells and limited expression on normal tissues. However, until the advent of brentuximab vedotin, CD30 remained an elusive target as antibody-based anti-CD30 immunotherapy had been largely clinically unsuccessful. Brentuximab vedotin (cAC10-vcMMAE, SGN-35) is an antibody-drug conjugate consisting of a chimeric anti-CD30 monoclonal antibody whereupon the potent microtubule inhibitor monomethyl auristatin E (MMAE) is attached via a valine-citrulline linker. Once bound to CD30, brentuximab vedotin is internalized and MMAE is released with the action of lysosomal enzymes on the linker. In phase I studies in relapsed or refractory Hodgkin lymphoma and anaplastic large cell lymphoma, brentuximab vedotin induced unprecedented responses with manageable toxicity. In phase II studies, brentuximab vedotin induced overall response rates of 75% and 86% in relapsed or refractory Hodgkin lymphoma and anaplastic large cell lymphoma, respectively. The results of these trials led to the accelerated approval of the drug by the US Food and Drug Administration in a patient population with few other alternative options. Brentuximab vedotin has overall manageable toxicity profile; however, cumulative peripheral neuropathy constitutes an important clinical consideration as it may limit prolonged administration of the drug. The mechanism by which brentuximab vedotin exerts its antitumor activity is not entirely clear. Diffusion of MMAE in the tumor microenvironment and cytotoxicity on bystander cells may in part explain its activity, especially in Hodgkin lymphoma. Herein, we review the biology of CD30 and brentuximab vedotin, and the clinical data that has accumulated thus far with SGN-35.

Anaplastic large cell lymphoma, ALK-negative

Anaplastic large cell lymphoma (ALCL), anaplastic lymphoma kinase (ALK)-negative (ALCL-ALK-) is a provisional entity in the WHO 2008 Classification that represents 2-3% of NHL and 12% of T-cell NHL. No particular risk factor has been clearly identified for ALCL, but a recent study showed an odds ratio of 18 for ALCL associated with breast implants. Usually, the architecture of involved organs is eroded by solid, cohesive sheets of neoplastic cells, with peripheral T-cell lymphoma-not otherwise specified (PTCL-NOS) and classical Hodgkin lymphoma being the main differential diagnoses. In this regard, staining for PAX5 and CD30 is useful. Translocations involving ALK are absent, TCR genes are clonally rearranged. CGH and GEP studies suggest a tendency of ALCL-ALK- to differ both from PTCL-NOS and from ALCL-ALK+. Patients with ALCL-ALK- are usually adults with a median age of 54-61 years, and a male-to-female ratio of 0.9. At presentation, ALCL-ALK- is often in III-IV stage, with B symptoms, high International Prognostic Index score, high lactate dehydrogenase serum levels, and an aggressive course. ALCL-ALK- presents with lymph node involvement in ∼50% of cases; extranodal spread (20%) is less common. Staging work-up for ALCL-ALK- is similar to that routinely used for nodal NHL. Overall prognosis is poor, with a 5-year OS of 30-49%, which is significantly worse when compared to OS reported in patients with ALCL-ALK+ (5-year: 70-86%). Patients with systemic ALCL exhibit a significantly better survival compared with patients with PTCL-NOS, with a 5-year OS of 51% and 32%, respectively. Age, PIT scoring system, β2-microglobulin, and bone marrow infiltration are the main prognostic factors. The expression of proteins involved in the regulation of apoptosis (caspase 3, Bcl-2, PI9) and of CD56 is related to clinical outcome. ALCL-ALK- is generally responsive to doxorubicin-containing chemotherapy, but relapses are frequent. CHOP is the most commonly used regimen to treat systemic ALCL with complete remission rates of 56%, and a 10-year DFS of 28%. Encouraging results have been reported with more intensive chemotherapy regimens. The addition of etoposide improved outcome. Alemtuxumab-CHOP regimen was associated with excellent remission rate but increased toxicity. The role of high-dose chemotherapy supported by ASCT has not been investigated in a trial of exclusively ALCL patients. When used in first remission, it was associated with a 5-year PFS of 64%. High-dose chemotherapy with ASCT is the standard therapeutic option for patients with relapsed or refractory disease. The role of allogeneic transplantation in patients with relapsed/refractory ALCL remains to be defined but there are data to support the contention that a graft-versus-lymphoma effect does exist. Myeloablative conditioning has been associated with 5-year PFS and OS of 40% and 41%, respectively, but a 5-year TRM of 33% was reported. Allo-SCT can be an option for relapsed/refractory ALCL in younger patients, preferably in the setting of a clinical trial. Pralatrexate, anti-CD30 monoclonal antibodies, brentuximab vedotin (SGN-35) in particular, (131)I-anti-CD45 radioantibody, yttrium-anti-CD25 radioimmunoconjugates, histone deacetylase inhibitors, bortezomib, gemcitabine, vorinostat, lenalidomide, and their combinations represent the most appealing chemotherapy and/or targeted agents to be investigated in future trials.

The discovery and development of brentuximab vedotin for use in relapsed Hodgkin lymphoma and systemic anaplastic large cell lymphoma

Progress has been made recently in developing antibody-drug conjugates (ADCs) that can selectively deliver cancer drugs to tumor cells. In principle, the idea is simple: by attaching drugs to tumor-seeking antibodies, target cells will be killed and nontarget cells will be spared. In practice, many parameters needed to be addressed to develop safe and effective ADCs, including the expression profiles of tumor versus normal tissues, the potency of the drug, the linker attaching the drug and placement of the drug on the antibody, and the pharmacokinetic and stability profiles of the resulting ADC. All these issues had been taken into account in developing brentuximab vedotin (Adcetris), an ADC that recently received accelerated approval by the US Food and Drug Administration for the treatment of relapsed Hodgkin lymphoma and systemic anaplastic large cell lymphoma (ALCL). Research is under way to extend the applications of brentuximab vedotin and to advance the field by developing other ADCs with new linker and conjugation strategies.

Brentuximab vedotin

Brentuximab vedotin (SGN-35; Adcetris®) is an anti-CD30 antibody conjugated via a protease-cleavable linker to the potent anti-microtubule agent monomethyl auristatin E (MMAE). Following binding to CD30, brentuximab vedotin is rapidly internalized and transported to lysosomes where MMAE is released and binds to tubulin, leading to cell cycle arrest and apoptosis. Several trials have shown durable antitumor activity with a manageable safety profile in patients with relapsed/refractory Hodgkin lymphoma, systemic anaplastic large cell lymphoma, or primary cutaneous CD30-positive lymphoproliferative disorders. Peripheral sensory neuropathy is a significant adverse event associated with brentuximab vedotin administration. Neuropathy symptoms are cumulative and dose-related. Multiple ongoing trials are currently evaluating brentuximab vedotin alone or in combination with other agents in relapsed/refractory patients, as well as patients with newly diagnosed disease.

7th cancer scientific forum of theCancéropôle Lyon Auvergne Rhône-Alpes: March 20-21, 2012, Lyon, France

The Innovative Approaches in Anti-Cancer Monoclonal Antibodies meeting, held on March 20, 2012 in Lyon, was organized by Cancéropôle Lyon Auvergne-Rhône-Alps in partnership with the French competitiveness cluster Lyonbiopôle. CLARA is one of the seven cancer research clusters within France in charge of facilitating Translational Oncology Research by taking into account the objectives of the French National Cancer Plans I and II and, in coordination with the French National Cancer Institute and local authorities (mainly Grand Lyon, Rhône County and Rhône-Alpes Region), to perform economic development of research findings. The contribution of lectures by outstanding speakers as described in this report, the organization of two-round tables: "Antibody treatment in cancer: Unmet needs in solid tumors and hematological malignancies," and "From chimeric to more than human antibodies," together with face-to-face meetings, was shared by over 230 participants. The lectures provided an overview of the commercial pipeline of monoclonal antibody (mAb) therapeutics for cancer; discussion of the distinction between biosimilar, biobetter and next generation therapeutic antibodies for cancer; updates on obinutuzumab and the use of mAbs in lymphoma; and discussion of antibody-drug conjugates.

Novel therapeutic agents for cutaneous T-Cell lymphoma

Mycosis fungoides (MF) and Sezary Syndrome (SS) represent the most common subtypes of primary Cutaneous T-cell lymphoma (CTCL). Patients with advanced MF and SS have a poor prognosis leading to an interest in the development of new therapies with targeted mechanisms of action and acceptable safety profiles. In this review we focus on such novel strategies that have changed the treatment paradigm of this rare malignancy.

ALK Signaling and Target Therapy in Anaplastic Large Cell Lymphoma

The discovery by Morris et al. (1994) of the genes contributing to the t(2;5)(p23;q35) translocation has laid the foundation for a molecular based recognition of anaplastic large cell lymphoma and highlighted the need for a further stratification of T-cell neoplasia. Likewise the detection of anaplastic lymphoma kinase (ALK) genetic lesions among many human cancers has defined unique subsets of cancer patients, providing new opportunities for innovative therapeutic interventions. The objective of this review is to appraise the molecular mechanisms driving ALK-mediated transformation, and to maintain the neoplastic phenotype. The understanding of these events will allow the design and implementation of novel tailored strategies for a well-defined subset of cancer patients.