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

Importance and Considerations of Antibody Engineering in Antibody-Drug Conjugates Development from a Clinical Pharmacologist's Perspective

Antibody-drug conjugates (ADCs) appear to be in a developmental boom, with five FDA approvals in the last two years and a projected market value of over $4 billion by 2024. Major advancements in the engineering of these novel cytotoxic drug carriers have provided a few early success stories. Although the use of these immunoconjugate agents are still in their infancy, valuable lessons in the engineering of these agents have been learned from both preclinical and clinical failures. It is essential to appreciate how the various mechanisms used to engineer changes in ADCs can alter the complex pharmacology of these agents and allow the ADCs to navigate the modern-day therapeutic challenges within oncology. This review provides a global overview of ADC characteristics which can be engineered to alter the interaction with the immune system, pharmacokinetic and pharmacodynamic profiles, and therapeutic index of ADCs. In addition, this review will highlight some of the engineering approaches being explored in the creation of the next generation of ADCs.

Poly-Gamma-Glutamic Acid (γ-PGA)-Based Encapsulation of Adenovirus to Evade Neutralizing Antibodies

In recent years, there has been an increasing interest in oncolytic adenoviral vectors as an alternative anticancer therapy. The induction of an immune response can be considered as a major limitation of this kind of application. Significant research efforts have been focused on the development of biodegradable polymer poly-gamma-glutamic acid (γ-PGA)-based nanoparticles used as a vector for effective and safe anticancer therapy, owing to their controlled and sustained-release properties, low toxicity, as well as biocompatibility with tissue and cells. This study aimed to introduce a specific destructive and antibody blind polymer-coated viral vector into cancer cells using γ-PGA and chitosan (CH). Adenovirus was successfully encapsulated into the biopolymer particles with an encapsulation efficiency of 92% and particle size of 485 nm using the ionic gelation method. Therapeutic agents or nanoparticles (NPs) that carry therapeutics can be directed specifically to cancerous cells by decorating their surfaces using targeting ligands. Moreover, in vitro neutralizing antibody response against viral capsid proteins can be somewhat reduced by encapsulating adenovirus into γ-PGA-CH NPs, as only 3.1% of the encapsulated adenovirus was detected by anti-adenovirus antibodies in the presented work compared to naked adenoviruses. The results obtained and the unique characteristics of the polymer established in this research could provide a reference for the coating and controlled release of viral vectors used in anticancer therapy.

Brentuximab vedotin in Hodgkin lymphoma and anaplastic large-cell lymphoma: an evidence-based review

Hodgkin lymphoma (HL) and anaplastic large-cell lymphoma (ALCL) account for ~10% and 2%-3% of all cases of lymphoid neoplasms, respectively. Up to 30% of patients with HL are refractory or relapse after first-line therapy, and elderly patients with HL represent a subgroup of patients with suboptimal responses to the currently available treatments. Five-year overall survival for ALCL patients is 50%-80% with conventional chemotherapy. Therefore, new therapeutic approaches are needed for these groups of patients. Brentuximab vedotin is a chimeric IgG1 anti-CD30 antibody-drug conjugate that has all the features that are necessary to make a substantive difference with the standard therapies in patients with HL and ALCL: a novel mechanism of action, single-agent activity, non-cross-resistance, and safety both in the relapsed-refractory and in the front-line setting. This review provides an update of the results of the most relevant clinical trials including brentuximab vedotin for patients with HL and ALCL conducted to date.

CD30 expression and survival in extranodal NK/T-cell lymphoma: a systematic review and meta-analysis

Background

The paradoxical reports about the prognostic value of the CD30 expression in extranodal NK/T-cell lymphoma (ENKTL) have restricted its further applications in clinical practice. To identify the common effects and the variation, we conducted this systematic review and meta-analysis.

Methods

PubMed, MEDLINE, Embase, and Web of Science were searched between January 1975 and 31 January 2017. The pooled hazard ratio was used to estimate the effect of the CD30 expression on overall survival. Bias was assessed by prespecified criteria referring to Reporting Recommendations for Tumor Marker Prognostic Studies and Newcastle-Ottawa Scale.

Results

Ten retrospective cohort studies with 310 patients are included. CD30 is associated with better overall survival significantly (HR 0.71, 95% CI 0.51 to 0.99, I² = 0%). A greater effect is observed among studies including participants predominant in regional involvement (HR 0.31, 95%CI 0.13 to 0.76, I² = 0%) compared with those in systemic involvement.

Conclusions

This study indicates that the CD30 expression is significantly associated with better prognosis in ENKTL, especially for patients with regional lymphoma involvement.

Breast Implant-Associated Anaplastic Large Cell Lymphoma: A Case Report and Review of the Literature

Breast implant–associated anaplastic large T-cell lymphoma has recently been recognized as an entity, with few reports describing the two common subtypes: in situ (indolent) and infiltrative. Recently, the infiltrative subtypes have been shown to be more aggressive requiring adjuvant chemotherapy. We report a rare case of breast implant–associated anaplastic large cell lymphoma (BIA-ALCL) in a 65-year-old Caucasian female following silicone breast implantation and multiple capsulectomies. We discuss the rare presentation of this disease, histopathologic features of the indolent and infiltrative subtypes of ALCL, and their clinical significance. We also review the literature for up-to-date information on the diagnosis and clinical management. Treatment modalities including targeted therapy are also discussed. Although BIA-ALCL is rare, it should always be considered as part of the differential diagnosis especially in women with breast implants. Given the increasing rate of breast reconstruction and cosmetic surgeries, we anticipate a continuous rise in incidence rates of this rare disease; thus, caution must be taken to avoid misdiagnosis.

Strategies and challenges for the next generation of antibody-drug conjugates

Antibody-drug conjugates (ADCs) are one of the fastest growing classes of oncology therapeutics. After half a century of research, the approvals of brentuximab vedotin (in 2011) and trastuzumab emtansine (in 2013) have paved the way for ongoing clinical trials that are evaluating more than 60 further ADC candidates. The limited success of first-generation ADCs (developed in the early 2000s) informed strategies to bring second-generation ADCs to the market, which have higher levels of cytotoxic drug conjugation, lower levels of naked antibodies and more-stable linkers between the drug and the antibody. Furthermore, lessons learned during the past decade are now being used in the development of third-generation ADCs. In this Review, we discuss strategies to select the best target antigens as well as suitable cytotoxic drugs; the design of optimized linkers; the discovery of bioorthogonal conjugation chemistries; and toxicity issues. The selection and engineering of antibodies for site-specific drug conjugation, which will result in higher homogeneity and increased stability, as well as the quest for new conjugation chemistries and mechanisms of action, are priorities in ADC research.

Anti-tubulin drugs conjugated to anti-ErbB antibodies selectively radiosensitize

Tumour resistance to radiotherapy remains a barrier to improving cancer patient outcomes. To overcome radioresistance, certain drugs have been found to sensitize cells to ionizing radiation (IR). In theory, more potent radiosensitizing drugs should increase tumour kill and improve patient outcomes. In practice, clinical utility of potent radiosensitizing drugs is curtailed by off-target side effects. Here we report potent anti-tubulin drugs conjugated to anti-ErbB antibodies selectively radiosensitize to tumours based on surface receptor expression. While two classes of potent anti-tubulins, auristatins and maytansinoids, indiscriminately radiosensitize tumour cells, conjugating these potent anti-tubulins to anti-ErbB antibodies restrict their radiosensitizing capacity. Of translational significance, we report that a clinically used maytansinoid ADC, ado-trastuzumab emtansine (T-DM1), with IR prolongs tumour control in target expressing HER2+ tumours but not target negative tumours. In contrast to ErbB signal inhibition, our findings establish an alternative therapeutic paradigm for ErbB-based radiosensitization using antibodies to restrict radiosensitizer delivery.

Drugs that sensitize tumour cells to ionizing radiation are prized because they can overcome resistance to radiotherapy. Here, the authors show that anti-tubulin drugs conjugated to cetuximab or trastuzumab can radiosensitize EGFR- or HER2-expressing tumors by increasing DNA damage and cell death due to ionizing radiation.

Augmented efficacy of brentuximab vedotin combined with ruxolitinib and/or Navitoclax in a murine model of human Hodgkin's lymphoma

Despite relative success of therapy for Hodgkin's lymphoma (HL), novel therapeutic agents are needed for patients with refractory or relapsed disease. Recently, anti-PD1 immunotherapy or treatment with the anti-CD30 toxin conjugate brentuximab vedotin (BV) have been associated with remissions; however, the median responses of complete responses (CRs) with the latter were only 6.7 mo. To obtain curative therapy, other effective agents, based on HL biology, would have to be given in combination with BV. Hodgkin's Reed-Sternberg (HRS) cells secrete cytokines including IL-6 and -13, leading to constitutive activation of JAK/STAT signaling. In the present study the JAK1/2 inhibitor ruxolitinib reduced phosphorylation of STAT3 and STAT6 and expression of c-Myc in the HL cell line HDLM-2. These changes were enhanced when, on the basis of a matrix screen of drug combinations, ruxolitinib was combined with the Bcl-2/Bcl-xL inhibitor Navitoclax. The combination augmented expression of Bik, Puma, and Bax, and attenuated Bcl-xL expression and the phosphorylation of Bad. The use of the two-agent combination of either ruxolitinib or Navitoclax with BV or the three-agent combination strongly activated Bax and increased activities of cytochrome c and caspase-9 and -3 that, in turn, led to cleavage of poly(ADP ribose) polymerase and Mcl-1. Either ruxolitinib combined with Navitoclax or BV alone prolonged survival but did not cure HDLM-2 tumor-bearing mice, whereas BV combined with ruxolitinib and/or with Navitoclax resulted in a sustained, complete elimination of the HDLM-2 HL. These studies provide scientific support for a clinical trial to evaluate BV combined with ruxolitinib in select patients with HL.

Combination therapy with brentuximab vedotin and cisplatin/cytarabine in a patient with primarily refractory anaplastic lymphoma kinase positive anaplastic large cell lymphoma

Anaplastic large cell lymphoma (ALCL) is a common subtype of the heterogeneous group of peripheral T-cell lymphomas, which is characterized by large pleomorphic cells with strong expression of CD30. Translocations involving ALK, the anaplastic lymphoma kinase gene, are associated with a favorable clinical outcome. Such ALK-positive ALCLs are usually responsive to a multidrug chemotherapy with CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone). However, there is no general consensus on the optimal therapy for relapsed or refractory ALCL. We report the case of a 24-year-old male suffering from ALK-positive ALCL with an uncommon manifestation of only extranodal disease in the gastric cardia region that showed primary refractoriness to standard CHOP chemotherapy. A combination therapy consisting of the anti-CD30 drug conjugate, brentuximab vedotin, and classical lymphoma salvage regimen DHAP (cisplatin, high-dose cytarabine and dexamethasone) was administered. Following two treatment cycles in 21-day intervals, the lymphoma showed considerable regression based on imaging diagnostics and no evidence of vital lymphoma in a subsequent biopsy. We did not observe any increase in toxicity; in particular, polyneuropathy and febrile neutropenia were not observed. In summary, we report that the antibody-drug conjugate brentuximab vedotin and a classical regimen used for aggressive lymphoma, DHAP, could be combined as salvage therapy in a case of refractory ALK-positive ALCL. Phase I/II studies will be required for safety and efficacy analysis.

ALK-negative anaplastic large cell lymphoma is a genetically heterogeneous disease with widely disparate clinical outcomes

Anaplastic lymphoma kinase (ALK)-negative anaplastic large cell lymphoma (ALCL) is a CD30-positive T-cell non-Hodgkin lymphoma that morphologically resembles ALK-positive ALCL but lacks chromosomal rearrangements of the ALK gene. The genetic and clinical heterogeneity of ALK-negative ALCL has not been delineated. We performed immunohistochemistry and fluorescence in situ hybridization on 73 ALK-negative ALCLs and 32 ALK-positive ALCLs and evaluated the associations among pathology, genetics, and clinical outcome. Chromosomal rearrangements of DUSP22 and TP63 were identified in 30% and 8% of ALK-negative ALCLs, respectively. These rearrangements were mutually exclusive and were absent in ALK-positive ALCLs. Five-year overall survival rates were 85% for ALK-positive ALCLs, 90% for DUSP22-rearranged ALCLs, 17% for TP63-rearranged ALCLs, and 42% for cases lacking all 3 genetic markers (P < .0001). Hazard ratios for death in these 4 groups after adjusting for International Prognostic Index and age were 1.0 (reference group), 0.58, 8.63, and 4.16, respectively (P = 7.10 × 10(-5)). These results were similar when restricted to patients receiving anthracycline-based chemotherapy, as well as to patients not receiving stem cell transplantation. Thus, ALK-negative ALCL is a genetically heterogeneous disease with widely disparate outcomes following standard therapy. DUSP22 and TP63 rearrangements may serve as predictive biomarkers to help guide patient management.