Combination of the Human Anti-CD30 Antibody 5F11 with Cytostatic Drugs Enhances Its Antitumor Activity against Hodgkin and Anaplastic Large Cell Lymphoma Cell Lines

The PTP1B mutant PTP1B∆2-4 is a positive regulator of the JAK/STAT signalling pathway in Hodgkin lymphoma

The neoplastic Hodgkin/Reed-Sternberg (HRS) cells of classical Hodgkin lymphoma (cHL) depend on chronic activation of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signalling pathways to maintain survival and proliferation. Accumulating reports highlight the importance of the inactivation or reduced expression of negative JAK/STAT regulators such as the protein-tyrosine phosphatase 1B (PTP1B/PTPN1) in this process. Various PTPN1 mRNA variants as well as truncated PTP1B proteins were identified in cHL cell lines and primary cHL tumour samples. These PTPN1 mRNA variants lack either one or several exon sequences and therefore render these PTP1B variants catalytically inactive. Here, we show that one of these mutants, PTP1B∆2-4, is not only a catalytically inactive variant, but also augmented the IL-4-induced JAK/STAT activity similar to the recently reported PTP1B∆6 splice variant. Moreover, while PTP1B∆6 diminished the activity and protein levels of PTP1BWT, PTP1BWT remained unaffected by PTP1B∆2-4, arguing for different molecular mechanisms of JAK/STAT modulation by PTP1B∆6 and PTP1B∆2-4. Collectively, these data indicate that PTPN1 variants missing one or more exon sequences originated either from alternative splicing or from gene mutation, create PTP1B gain-of-function variants with oncogenic potential by augmenting JAK/STAT signalling in cHL.

Brentuximab vedotin with gemcitabine for paediatric and young adult patients with relapsed or refractory Hodgkin's lymphoma (AHOD1221): a Children's Oncology Group, multicentre single-arm, phase 1-2 trial

BACKGROUND

Patients with primary refractory Hodgkin's lymphoma or early relapse have a poor prognosis. Although many salvage regimens have been developed, there is no standard of care. Brentuximab vedotin and gemcitabine have been shown to be active in patients with relapsed or refractory Hodgkin's lymphoma when used as monotherapy, and each has been successfully used in combination with other agents. Preclinical data suggest that brentuximab vedotin can sensitise lymphoma cells to gemcitabine, supporting the use of the combination. We aimed to define the safety and efficacy of brentuximab vedotin with gemcitabine in children and young adults with primary refractory Hodgkin's lymphoma or early relapse.

METHODS

In this Children's Oncology Group, multicentre, single-arm, phase 1-2 trial, we recruited patients with Hodgkin's lymphoma from hospitals across the USA and Canada. Eligible patients were aged younger than 30 years, had no previous brentuximab vedotin exposure, and had primary refractory disease or relapse of less than 1 year from completion of initial treatment. Each 21-day cycle consisted of 1000 mg/m2 intravenous gemcitabine on days 1 and 8 and intravenous brentuximab vedotin on day 1 at 1·4 mg/kg or 1·8 mg/kg. The primary objectives were to establish the recommended phase 2 dose of brentuximab vedotin in this combination, the safety of the combination, and the proportion of patients who achieved a complete response among those treated at the recommended phase 2 level, within four cycles of treatment. This trial is registered with ClinicalTrials.gov, number NCT01780662.

FINDINGS

Between Feb 5, 2013, and Aug 19, 2016, 46 patients were enrolled, including one who was found to be ineligible, in the two phases of the study. The recommended phase 2 dose of brentuximab vedotin was 1·8 mg/kg in combination with gemcitabine 1000 mg/m2. 24 (57%) of 42 evaluable patients (95% CI 41-72) given this dose level had a complete response within the first four cycles of treatment. Four (31%) of 13 patients with a partial response or stable disease had all target lesions with Deauville scores of 3 or less after cycle 4. By modern response criteria, these were also complete responses (total number with complete response 28 [67%] of 42 [95% CI 51-80]). The most common grade 3-4 adverse events in all 42 participants treated at the recommended phase 2 dose were neutropenia (15 [36%]), rash (15 [36%]), transaminitis (9 [21%]), and pruritus (4 [10%]). There were no treatment-related deaths.

INTERPRETATION

Brentuximab vedotin with gemcitabine is a safe combination treatment with a tolerable toxicity profile for patients with primary refractory Hodgkin's lymphoma or high-risk relapse. The preliminary activity of this combination shown in this trial warrants further investigation in randomised controlled trials.

FUNDING

National Institutes of Health and the St. Baldrick's Foundation.

A novel PTPN1 splice variant upregulates JAK/STAT activity in classical Hodgkin lymphoma cells

Chronic activation of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathways is a hallmark of a variety of B-cell lymphomas, including classical Hodgkin lymphoma (cHL). Constitutive JAK/STAT signaling is crucial for survival and proliferation of Hodgkin/Reed-Sternberg (HRS) cells, the malignant cells of cHL. Although the molecular basis of this constitutive JAK/STAT signaling in cHL has not been completely understood, accumulating reports highlight the role of an inactivation or reduced expression of negative JAK/STAT regulators such as silencer of cell signaling 1 (SOCS1) or protein-tyrosine phosphatase 1B (PTP1B) in this process. Here, we report the expression of truncated PTP1B mRNA variants identified in cHL cell lines and primary cHL tumor samples lacking either 1 or several exon sequences. One of these novel PTP1B variants, a splice variant lacking exon 6 (PTP1BΔ6), was found expressed at low levels in cHL cell lines. However, serum stimulation of cHL augmented the expression of PTP1BΔ6 significantly. Functional characterization of PTP1BΔ6 revealed a positive effect on interferon-γ- and interleukin-4-induced JAK/STAT activity in HEK293 or HEK293-STAT6 cells, and on the basal STAT activity in stably transfected L-428 and U-HO1 cHL cell lines. Furthermore, PTP1BΔ6 expression increased the proliferation of L-428 and U-HO1 cells and reduced cytotoxic effects of the chemotherapeutical agents gemcitabine and etoposide distinctively. Collectively, these data indicate that PTP1BΔ6 is a positive regulator of JAK/STAT signaling in cHL.

Multimodality Technologies in the Assessment of Hematolymphoid Neoplasms

Accurate assessment of tissues for hematolymphoid neoplasms requires an integrated multiparameter approach. Although morphologic examination by light microscopy remains the mainstay of initial assessment for hematolymphoid neoplasms, immunophenotypic analysis by immunohistochemistry and/or flow cytometry is essential to determine the pattern of differentiation and to detect minimal disease when morphology is inconclusive. In some cases, immunophenotypic analysis provides additional information for targeted immunotherapy and prognostication. Genotypic studies, including cytogenetics, fluorescence in situ hybridization, DNA microarray, polymerase chain reaction, and/or next-generation sequencing, are also imperative for subclassification of the genetically defined disease entities in the current World Health Organization classification of hematolymphoid neoplasms. Moreover, genotypic studies can establish clonality, stratify patients to determine appropriate treatment, and monitor patients for treatment response.

Speed bumps on the road to a chemotherapy-free world for lymphoma patients

With the increasing number of targeted agents for the treatment of patients with lymphoid malignancies comes the promise of safe and effective chemotherapy-free treatment strategies. A number of single agents, such as ibrutinib and idelalisib, have demonstrated impressive efficacy with a favorable toxicity profile. The observations that most responses are, however, partial and treatment duration is indefinite have stimulated interest in combinations of these agents with chemotherapy as well as with each other. Despite the promise of this approach, several recent trials of combinations of agents have been terminated as the result of life-threatening and fatal complications. Such outcomes have generated a cautionary note of the potential for unforeseen adverse effects that challenge drug development and mitigate against the empiric combination of such drugs outside of a clinical trial setting.

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.

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.

CD30 as a therapeutic target for lymphoma

Hodgkin's lymphoma (HL) and ALK(+) anaplastic large-cell lymphoma (ALCL) have become highly curable due to the success of modern regimens of chemotherapy and radiotherapy. However, up to one-third of the patients experience relapse or do not respond to first-line therapy, and half of them relapse again after secondary therapy with limited options for further treatment. In the last 15 years, monoclonal antibodies (mAbs) directed to surface receptors became a new and valuable therapeutic option in many hematologic malignancies. Due to its restricted expression on normal activated lymphocytes and its high expression on malignant cells, CD30 represents an attractive target molecule for HL and ALCL therapy. However, unconjugated CD30 mAbs have demonstrated a lack of objective clinical responses in patients with recurrent HL. CD30 exhibits complex signaling pathways, and binding of its natural ligand or anti-CD30 mAbs can induce apoptosis but may also promote proliferation and activation depending on the cellular context. Moreover, CD30 rapidly internalizes after crosslinking, which counteracts efficient recruitment of immunologic effectors but also provides the opportunity to transfer cytotoxic payloads coupled to CD30-specific mAbs into the tumor cells. Several tumor targeting approaches have been studied, including radio-immunoconjugates, immunotoxins, immunoRNases, immunokinases, and antibody drug conjugates (ADCs). In 2011, the ADC brentuximab-vedotin, consisting of the CD30-specific chimeric mAb cAC10 and the potent tubulin toxin monomethyl auristatin E, gained regulatory approval as a well tolerated and highly active drug in patients with refractory and relapsed HL and ALCL. SGN-35 is on the way to being incorporated in the standard management of CD30(+) lymphoma with significant therapeutic impact. This review gives a critical overview about anti-CD30 therapies with unconjugated, engineered, and conjugated mAbs and the therapeutic challenges of treatment of CD30(+) lymphoma.

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.

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.

Peripheral T-cell lymphoma

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of clinically aggressive diseases associated with poor outcome. Studies that focus specifically on PTCL are emerging, with the ultimate goal of improved understanding of disease biology and the development of more effective therapies. However, one of the difficulties in classifying and studying treatment options in clinical trials is the rarity of these subtypes. Various groups have developed lymphoma classifications over the years, including the World Health Organization, which updated its classification in 2008. This article briefly reviews the major lymphoma classification schema, highlights contributions made by the collaborative International PTCL Project, discusses prognostic issues and gene expression profiling, and outlines therapeutic approaches to PTCL. These include the standard chemotherapeutic regimens and other modalities incorporating antifolates, conjugates, histone deacetylase inhibitors, monoclonal antibodies, nucleoside analogs, proteasome inhibitors, and signaling inhibitors. As this review emphasizes, the problem has now evolved into an abundance of drugs and too few patients available to test them. Collaborative groups will aid in future efforts to find the best treatment strategies to improve the outcome for patients with PTCL.

Novel antibodies against follicular non-Hodgkin's lymphoma

The anti-CD20 monoclonal antibody rituximab has revolutionized the treatment of patients with follicular B-cell lymphoma. With the combination of chemotherapy and rituximab the overall survival rate has increased with approximately 30%. Unfortunately, there is resistance to rituximab with relapse of the disease in about 60% of the patients during the first five years of treatment and eventually in all patients. To this end, there is a need to develop improved anti-CD20 monoclonal antibodies and antibodies that target other attractive molecules expressed on the follicular lymphoma cell. This review describes the development and clinical achievements so far of next generation anti-CD20 and other antibodies in the treatment of follicular B-cell lymphoma.

Serious pulmonary toxicity in patients with Hodgkin's lymphoma with SGN-30, gemcitabine, vinorelbine, and liposomal doxorubicin is associated with an FcγRIIIa-158 V/F polymorphism

BACKGROUND

Based on in vitro synergistic cytotoxicity when anti-CD30 antibodies are combined with gemcitabine, the Cancer and Leukemia Group B conducted a double-blind, randomized, phase II trial of SGN-30 with gemcitabine, vinorelbine, and pegylated liposomal doxorubicin (GVD) in patients with relapsed Hodgkin's lymphoma.

PATIENTS AND METHODS

In part 1 of the trial, 16 patients received SGN-30 with GVD to assess the safety of the combination. In part 2, patients were randomly allocated to SGN-30 (n = 7) or placebo (n = 7) with GVD to determine overall response rate (ORR).

RESULTS

ORR in all 30 patients was 63% (65% with SGN-30 plus GVD, n = 23, and 57% with placebo plus GVD, n = 7). Median event-free survival was 9.0 months, with no difference between the two arms. Grades 3-5 pneumonitis occurred in five patients receiving SGN-30 and GVD, leading to premature closure of the trial. All five patients with pulmonary toxicity had a V/F polymorphism in the FcγRIIIa gene (P = 0.008).

CONCLUSIONS

Together with historical data demonstrating a 2% incidence of pulmonary events with GVD, these results indicate that SGN-30 cannot safely be administered concurrently. The risk of pneumonitis with SGN-30 and GVD is greatest in patients with an FcγRIIIa V/F polymorphism.

Using an RNA aptamer probe for flow cytometry detection of CD30-expressing lymphoma cells

Aptamers are small molecular ligands composed of short oligonucleotides that bind targets with high affinity. In contrast to antibodies, as synthetic oligonucleotides, aptamers have lower production costs and elicit no antigenic reactions. Therefore, aptamers are potential agents for disease diagnosis and treatment. In this study, we validate a fluorescently labeled RNA aptamer, which has been reported to bind specifically to mouse CD30 proteins in solution, for human CD30 protein recognition on intact cells. The aptamer probe was tested with cultured anaplastic large cell lymphoma and Hodgkin's lymphoma cells that express high levels of CD30. Flow cytometry and fluorescence microscopy showed specific and sensitive binding of the aptamer probe to CD30-expressing lymphoma cells at low concentrations (0.3 nM). Studies performed on multiple cell lines and nuclear cells from healthy donors confirmed that the CD30 aptamer and anti-CD30 antibody, the standard clinical probe, recognized the same set of cells. The potential application of multicolor flow cytometry analysis using the CD30 aptamer probe and antibodies was also shown. In conclusion, the developed CD30 aptamer probe could act as a replacement and/or a supplement for antibodies in the diagnosis of the CD30-expressing lymphomas.

Heat shock protein 90 inhibitor BIIB021 (CNF2024) depletes NF-kappaB and sensitizes Hodgkin's lymphoma cells for natural killer cell-mediated cytotoxicity

PURPOSE

In Hodgkin's lymphoma, constitutive activation of NF-kappaB promotes tumor cell survival and proliferation. The molecular chaperone heat shock protein 90 (HSP90) has immune regulatory activity and supports the activation of NF-kappaB in Hodgkin's lymphoma cells.

EXPERIMENTAL DESIGN

We analyzed the effect of HSP90 inhibition on viability and NF-kappaB activity in Hodgkin's lymphoma cells and the consequences for their recognition and killing through natural killer (NK) cells.

RESULTS

The novel orally administrable HSP90 inhibitor BIIB021 (CNF2024) inhibited Hodgkin's lymphoma cell viability at low nanomolar concentrations in synergy with doxorubicin and gemcitabine. Annexin V/7-aminoactinomycin D binding assay revealed that BIIB021 selectively induced cell death in Hodgkin's lymphoma cells but not in lymphocytes from healthy individuals. We observed that BIIB021 inhibited the constitutive activity of NF-kappaB and this was independent of IkappaB mutations. Furthermore, we analyzed the effect of HSP90 inhibition on NK cell-mediated cytotoxicity. BIIB021 induced the expression of ligands for the activating NK cell receptor NKG2D on Hodgkin's lymphoma cells resulting in an increased susceptibility to NK cell-mediated killing. In a xenograft model of Hodgkin's lymphoma, HSP90 inhibition significantly delayed tumor growth.

CONCLUSIONS

HSP90 inhibition has direct antitumor activity in Hodgkin's lymphoma in vitro and in vivo. Moreover, HSP90 inhibition may sensitize Hodgkin's lymphoma cells for NK cell-mediated killing via up-regulation of ligands engaging activating NK cell receptors.

Immunotherapies for Hodgkin's lymphoma

Multiple immune evasion strategies characterize the pathobiology of Hodgkin's lymphoma. These must be considered when developing and testing immunotherapeutic approaches for this disease. The clinical experience with adoptive immunotherapy of Epstein-Barr virus positive tumors, and with monoclonal antibodies directed against CD30, CD20, and other antigens, is herein reviewed.

A phase 1 multidose study of SGN-30 immunotherapy in patients with refractory or recurrent CD30+ hematologic malignancies

Phase 1 testing of SGN-30, a chimeric monoclonal antibody for the treatment of CD30+ malignancies, was conducted in a multicenter study. To explore the safety profile and establish the maximum tolerated dose (MTD), 24 patients with refractory or relapsed Hodgkin lymphoma or CD30+ non-Hodgkin lymphoma received 6 weekly doses of intravenous SGN-30 at 4 dose levels (2, 4, 8, or 12 mg/kg). Serum concentrations of SGN-30 rose rapidly and were dose dependent. Adverse events were mild, with nausea, fatigue, and fever attributed to study treatment. One episode of hypersensitivity rash was reported. The MTD was not reached. Serious adverse events included herpes zoster (n = 2), influenza, and pneumonia. One patient with cutaneous anaplastic large cell lymphoma (8 mg/kg) achieved a complete response. Six patients, of whom 4 had Hodgkin lymphoma, achieved stable disease with durations ranging from 6 to 16 months. The pharmacokinetic profile of SGN-30 showed a biphasic disposition, and estimated half-lives ranging between 1 to 3 weeks. The 6 weekly infusions of SGN-30 resulted in approximately 2- to 3-fold accumulation in serum exposures consistently across the dose range. These results demonstrate that weekly administration of SGN-30 is safe and has modest clinical activity in patients with CD30+ tumors. This trial is registered at http://www.ClinicalTrials.gov as no. NCT00051597.

Human monoclonal antibodies from transgenic mice

Since the 1986 regulatory approval of muromonomab-CD3, a mouse monoclonal antibody (MAb) directed against the T cell CD3epsilon antigen, MAbs have become an increasingly important class of therapeutic compounds in a variety of disease areas ranging from cancer and autoimmune indications to infectious and cardiac diseases. However, the pathway to the present acceptance of therapeutic MAbs within the pharmaceutical industry has not been smooth. A major hurdle for antibody therapeutics has been the inherent immunogenicity of the most readily available MAbs, those derived from rodents. A variety of technologies have been successfully employed to engineer MAbs with reduced immunogenicity. Implementation of these antibody engineering technologies involves in vitro optimization of lead molecules to generate a clinical candidate. An alternative technology, involving the engineering of strains of mice to produce human instead of mouse antibodies, has been emerging and evolving for the past two decades. Now, with the 2006 US regulatory approval of panitumumab, a fully human antibody directed against the epidermal growth factor receptor, transgenic mice expressing human antibody repertoires join chimerization, CDR grafting, and phage display technologies, as a commercially validated antibody drug discovery platform. With dozens of additional transgenic mouse-derived human MAbs now in clinical development, this new drug discovery platform appears to be firmly established within the pharmaceutical industry.

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

Purpose

MDX-060 is a human anti-CD30 immunoglobulin (Ig) G1κ monoclonal antibody that inhibits growth of CD30-expressing tumor cells in preclinical models. To determine the safety, maximum-tolerated dose (MTD), and efficacy of MDX-060 in patients with relapsed or refractory CD30+ lymphomas, sequential phase I and II studies were performed.

Patients and Methods

In the phase I portion, MDX-060 was administered intravenously at doses of 0.1, 1, 5, or 10 mg/kg weekly for 4 weeks to cohorts of three to six patients. Twenty-one patients—16 with Hodgkin's lymphoma (HL), three with anaplastic large-cell lymphoma (ALCL), and two with CD30+ T-cell lymphoma—were enrolled. Because of the lack of a defined MTD or dose-response correlation, the phase II portion was amended to include several dose levels. In the phase II portion, an additional 51 patients, 47 with HL and four with ALCL, were treated at doses of 1, 5, 10, and 15 mg/kg.

Results

MDX-060 was well tolerated, and an MTD has not been identified. Only 7% of patients experienced grade 3 or 4 treatment-related adverse events. Among the 72 patients treated, clinical responses were observed in six. Twenty-five patients had stable disease, including five who remained free from progression 1 year after treatment.

Conclusion

MDX-060 was well tolerated at doses up to 15 mg/kg. MDX-060 has limited activity as a single agent, but the minimal toxicity observed and the significant proportion of patients with stable disease suggests that further study of MDX-060 in combination with other therapies is warranted.

Anaplastic Large‐Cell Lymphoma, T‐/Null‐Cell Type

Anaplastic large-cell lymphoma, T-/null-cell type (ALCL), is a rare disease that has only been well characterized for two decades. Despite this, the biology of ALCL is better understood than that of many other more common variants of lymphoma. This review focuses on the pathophysiology, clinical presentation, and therapy of ALCL, including stem cell transplantation. In particular, the text emphasizes how novel prognostic features and the evolving understanding of the biology of this disease will influence treatment selection and drug development.

Human antibodies from transgenic animals

Laboratory mice provide a ready source of diverse, high-affinity and high-specificity monoclonal antibodies (mAbs). However, development of rodent antibodies as therapeutic agents has been impaired by the inherent immunogenicity of these molecules. One technology that has been explored to generate low immunogenicity mAbs for in vivo therapy involves the use of transgenic mice expressing repertoires of human antibody gene sequences. This technology has now been exploited by over a dozen different pharmaceutical and biotechnology companies toward developing new therapeutic mAbs, and currently at least 33 different drugs in clinical testing--including several in pivotal trials--contain variable regions encoded by human sequences from transgenic mice. The emerging data from these trials provide an early glimpse of the safety and efficacy issues for these molecules. Nevertheless, actual product approval, the biggest challenge so far, is required to fully validate this technology as a drug discovery tool. In the future, it may be possible to extend this technology beyond rodents and use transgenic farm animals to directly generate and produce human sequence polyclonal sera.

The fully human anti-CD30 antibody 5F11 activates NF-κB and sensitizes lymphoma cells to bortezomib-induced apoptosis

5F11, a fully human monoclonal antibody directed against CD30, effectively induces killing of CD30-expressing lymphoma cell lines in vitro and in animal models. A recently conducted phase 1/2 study shows that 5F11 is well tolerated in heavily pretreated patients with relapsed and refractory CD30+ lymphoma and has some clinical activity. In the present study, we demonstrate that 5F11 activates nuclear factor κB (NF-κB) and the anti-apoptotic protein cellular FLICE (Fas-associating protein with death domain-like interleukin-1β-converting enzyme) inhibitory protein (c-flip) in Hodgkin lymphoma (HD)-derived cell lines, which might cause apoptosis resistance, thus limiting the clinical use of 5F11. To overcome this resistance, we combined 5F11 with the proteasome inhibitor bortezomib, which has been shown to suppress NF-κB activity. This combination revealed a synergistic cytotoxic effect in vitro and in a human HD xenograft model provided that 5F11 precedes bortezomib treatment. We conclude that initial 5F11-mediated NF-κB signaling sensitizes the tumor cells to bortezomib-induced cell death. These data suggest a therapeutic value of this combination for HD patients. (Blood. 2005;106:1839-1842)

Signaling via the anti-CD30 mAb SGN-30 sensitizes Hodgkin's disease cells to conventional chemotherapeutics

SGN-30, a monoclonal antibody with activity against CD30+ malignancies, is currently in phase II clinical evaluation for treatment of Hodgkin's disease (HD) and anaplastic large cell lymphoma. The mechanisms underlying SGN-30's antitumor activity were investigated using cDNA array of L540 cells. SGN-30 treatment activated NF-kappaB and modulation of several messages including the growth regulator p21WAF1/CIP1 (p21) and cellular adhesion marker ICAM-1. p21 protein levels increased coincident with growth arrest and Annexin V/PI staining in treated HD cells. To determine if SGN-30-induced growth arrest would sensitize tumor cells to chemotherapeutics used against HD, L540cy and L428 cells were exposed to SGN-30 in combination with a panel of cytotoxic agents and resultant interactions quantified by the Combination Effects Method. Interactions between SGN-30 and all cytotoxic agents examined were additive or better. These in vitro data translated to increased efficacy of SGN-30 and bleomycin against L540cy tumor xenografts. In addition to direct cell killing, SGN-30 affects growth arrest and drug sensitization through growth regulating and proapoptotic machinery. Importantly, these data suggest that SGN-30 can enhance the efficacy of standard chemotherapies used to treat patients with CD30+ malignancies.