Brentuximab vedotin: a review of its use in patients with hodgkin lymphoma and systemic anaplastic large cell lymphoma following previous treatment failure

An Auristatin nanoconjugate targeting CXCR4+ leukemic cells blocks acute myeloid leukemia dissemination

Background

Current acute myeloid leukemia (AML) therapy fails to eliminate quiescent leukemic blasts in the bone marrow, leading to about 50% of patient relapse by increasing AML burden in the bone marrow, blood, and extramedullar sites. We developed a protein-based nanoparticle conjugated to the potent antimitotic agent Auristatin E that selectively targets AML blasts because of their CXCR4 receptor overexpression (CXCR4+) as compared to normal cells. The therapeutic rationale is based on the involvement of CXCR4 overexpression in leukemic blast homing and quiescence in the bone marrow, and the association of these leukemic stem cells with minimal residual disease, dissemination, chemotherapy resistance, and lower patient survival.

Methods

Monomethyl Auristatin E (MMAE) was conjugated with the CXCR4 targeted protein nanoparticle T22-GFP-H6 produced in E. coli. Nanoconjugate internalization and in vitro cell viability assays were performed in CXCR4+ AML cell lines to analyze the specific antineoplastic activity through the CXCR4 receptor. In addition, a disseminated AML animal model was used to evaluate the anticancer effect of T22-GFP-H6-Auristatin in immunosuppressed NSG mice (n = 10/group). U of Mann-Whitney test was used to consider if differences were significant between groups.

Results

T22-GFP-H6-Auristatin was capable to internalize and exert antineoplastic effects through the CXCR4 receptor in THP-1 and SKM-1 CXCR4+ AML cell lines. In addition, repeated administration of the T22-GFP-H6-Auristatin nanoconjugate (9 doses daily) achieves a potent antineoplastic activity by internalizing specifically in the leukemic cells (luminescent THP-1) to selectively eliminate them. This leads to reduced involvement of leukemic cells in the bone marrow, peripheral blood, liver, and spleen, while avoiding toxicity in normal tissues in a luminescent disseminated AML mouse model.

Conclusions

A novel nanoconjugate for targeted drug delivery of Auristatin reduces significantly the acute myeloid leukemic cell burden in the bone marrow and blood and blocks its dissemination to extramedullar organs in a CXCR4+ AML model. This selective drug delivery approach validates CXCR4+ AML cells as a target for clinical therapy, not only promising to improve the control of leukemic dissemination but also dramatically reducing the severe toxicity of classical AML therapy.

Current Development of Monoclonal Antibodies in Cancer Therapy

Exploiting the unique specificity of monoclonal antibodies has revolutionized the treatment and diagnosis of haematological and solid organ malignancies; bringing benefit to millions of patients over the past decades. Recent achievements include conjugating antibodies with toxic payloads resulting in superior efficacy and/or reduced toxicity, development of molecular imaging techniques targeting specific antigens for use as predictive and prognostic biomarkers, the development of novel bi- and tri-specific antibodies to enhance therapeutic benefit and abrogate resistance and the success of immunotherapy agents. In this chapter, we review an overview of antibody structure and function relevant to cancer therapy and provide an overview of pivotal clinical trials which have led to regulatory approval of monoclonal antibodies in cancer treatment. We further discuss resistance mechanisms and the unique side effects of each class of antibody and provide an overview of emerging therapeutic agents.

Discovery of an SSTR2-Targeting Maytansinoid Conjugate (PEN-221) with Potent Activity in Vitro and in Vivo

Somatostatin receptor 2 (SSTR2) is frequently overexpressed on several types of solid tumors, including neuroendocrine tumors and small-cell lung cancer. Peptide agonists of SSTR2 are rapidly internalized upon binding to the receptor and linking a toxic payload to an SSTR2 agonist is a potential method to kill SSTR2-expressing tumor cells. Herein, we describe our efforts towards an efficacious SSTR2-targeting cytotoxic conjugate; examination of different SSTR2-targeting ligands, conjugation sites, and payloads led to the discovery of 22 (PEN-221), a conjugate consisting of microtubule-targeting agent DM1 linked to the C-terminal side chain of Tyr³-octreotate. PEN-221 demonstrates in vitro activity which is both potent (IC₅₀ = 10 nM) and receptor-dependent (IC₅₀ shifts 90-fold upon receptor blockade). PEN-221 targets high levels of DM1 to SSTR2-expressing xenograft tumors, which has led to tumor regressions in several SSTR2-expressing xenograft mouse models. The safety and efficacy of PEN-221 is currently under evaluation in human clinical trials.

Isolated hypoglossal nerve palsy as a presenting symptom of metastatic peripheral T-cell lymphoma - not otherwise specified (PTCL-NOS): a unique case & a review of the literature

Extensive and significant technological advancements have enhanced the sensitivity and accuracy of the pathologic classification, diagnosis, and therapeutics of lymphoma. These advances have prompted a more comprehensive understanding of neoplastic behavior and have led to improvements in both treatment and prognosis. This paper presents a comprehensive review of lymphoma and features a case report of a unique presentation of peripheral T-cell lymphoma - not otherwise specified that presented with isolated hypoglossal nerve dysfunction.

Antineoplastic Agents. 605. Isoquinstatins

In order to further explore quinoline-type structural modification of the powerful anticancer drug dolastatin 10, an Indian Ocean sea hare constituent and parent molecule of the very successful antibody drug conjugate (ADC) Adcetris, our recent quinstatin study has been extended by replacing the quinoline ring with an isoquinoline. The resulting isoquinstatins (4-6) were modified to N-terminal desmethylisoquinstatins (7-9) and, in turn, bonded to appropriate linker units to give linker-desmethylisoquinstatin conjugates 11-13 in preparation for eventual monoclonal antibody attachment. Comparison of the new isoquinstatins with their quinstatin counterparts against six human cancer cell lines indicated the isoquinstatins to have GI₅₀ values that were comparable to or somewhat higher than those of the isomeric quinstatins. However, desmethylisoquinstatin 5 (7) was significantly more potent than its desmethylquinstatin 5 analogue. When evaluated against quinstatin 8, its isoquinstatin 8 (6) counterpart was somewhat less potent. In general, the isoquinstatins evaluated proved to be quite strong cancer cell growth inhibitors.

Antineoplastic Agents. 604. The Path of Quinstatin Derivatives to Antibody Drug Conjugates

To further evaluate the exceptional cancer cell growth inhibition by the quinstatins, of which one of the series, quinstatin 8, approaches the exceptional cytotoxic activity of the parent dolastatin 10 (1), four of the quinstatins have been converted to desmethyl derivatives. Three of the four (4, 5, and 8 [7b-d]) were next bonded to the linker (8) employed in the synthesis of the very successful and structurally related anticancer drug Adcetris (3). Owing to these structural modifications, a next step could be taken by bonding to a monoclonal antibody, thereby producing an antibody drug conjugate (ADC) related to Adcetris structurally but with the possibility of a wider spectrum of activity and utility.

Interactions Between Therapeutic Proteins and Small Molecules: The Shared Role of Perpetrators and Victims

Therapeutic proteins (TPs) are becoming increasingly important as therapeutic agents. A consequence of expanding their clinical indications is coadministration with well-established small-molecule drugs (sMDs), which could lead to unpredictable effects. According to the existing regulatory guidance, the development of an sMD includes the evaluation of potential drug-drug interactions (DDIs). For TPs, only a few drug interaction studies have been published. Limited clinically relevant models, long half-lives, and complex elimination pathways are among the associated difficulties.

Sacituzumab govitecan: an antibody-drug conjugate

INTRODUCTION

Despite advances in the diagnosis and treatment of patients with cancer, patients with metastatic cancer have limited therapeutic options after initial lines of therapy. Understanding tumor biology has translated into the identification of actionable targets that resulted in therapeutics. Antibody-drug conjugates (ADC) are capitalizing on this explosion of scientific information. ADCs allow an antibody to a unique target to be conjugated via an innovative linker, to a highly toxic drug which is delivered to its target. Sacituzumab govitecan is an ADC that combines the active molecule in irinotecan, SN-38, to an antibody targeting trop2. Areas covered: In this review, the authors introduce the reader to the ADC sacituzumab govitecan providing the reader with details about its pharmacokinetics, pharmacodynamics, efficacy and safety. The authors also give their expert analysis about its potential future use. Expert opinion: Sacituzumab govitecan is a novel and well-tolerated therapeutic showing promising results in difficult to treat cancers. Further studies are underway to optimize the group of patients that would benefit from it. Given its excellent performance, we are cautiously optimistic it will be approved by the FDA.

Brentuximab Vedotin: A Review in CD30-Positive Hodgkin Lymphoma

Intravenous brentuximab vedotin (ADCETRIS®) is a targeted antibody-drug conjugate (ADC) active against CD30-positive cancer cells such as those associated with classical Hodgkin lymphoma (HL). In noncomparative, phase 2 trials and in the real-world setting, salvage therapy with brentuximab vedotin resulted in high objective response (complete plus partial remission) rates in patients with relapsed or refractory CD30-positive HL, including as retreatment in patients who had an objective response to previous brentuximab vedotin therapy and subsequently relapsed. These beneficial outcomes were durable during long-term follow-up. As consolidation therapy after autologous haematopoietic stem cell transplant (ASCT) in the multinational, phase 3 AETHERA trial, brentuximab vedotin prolonged progression-free-survival (PFS) compared with placebo at a median follow-up of 30 months (primary analysis), with a 43% reduction in the risk of disease progression or death. The beneficial effects of brentuximab vedotin consolidation therapy were maintained during long-term follow-up. In the clinical trial and real-world setting, brentuximab vedotin had an acceptable tolerability and safety profile, with most adverse events manageable with dose reductions and/or delays [including peripheral sensory neuropathy (PSN) and neutropenia]. With a paucity of treatments available for many patients with relapsed or refractory HL, brentuximab vedotin represents an important option for the management of patients who have failed high-dose chemotherapy/ASCT or at least two prior chemotherapy regimens and as post-ASCT consolidation therapy in patients who are at increased risk/high-risk of relapse or progression after ASCT.

Marine-Derived Pharmaceuticals - Challenges and Opportunities

Marine biosphere is the largest one of the earth and harbors an enormous number of different organisms. Living conditions differ fundamentally from those in terrestrial environment. The production of specific secondary metabolites is an important adaption mechanism of marine organisms to survive in the sea. These metabolites possess biological activities which make them interesting as possible drugs for human. The review presents sources, chemistry, production and pharmacology of FDA approved marine derived pharmaceuticals arranged according to their therapeutic indication. Four of the presently seven approved drugs are used for the treatment of cancer. Each another one is applicated for treatment of viral diseases, chronic pain and to lower triglyceride level in blood. Some other products are of interest in diagnostic and as experimental tools. Besides, this article describes challenges in drug development from marine sources, especially the supply problem.

Brentuximab Vedotin Therapy for Cutaneous Lesions in T-Prolymphocytic Leukemia: A Case Report

We present an 88-year-old male with simultaneous T-cell prolymphocytic leukemia and stable smoldering myeloma with excellent initial response to three months of alemtuzumab. The patient relapsed at twelve months with severe cutaneous disease. Biopsy of a representative plaque demonstrated CD30 positivity in rare malignant lymphocytes. The patient demonstrated no response to reintroduction with a full course of alemtuzumab. He was therefore treated with brentuximab vedotin, resulting in partial remission of skin involvement that persisted for three months.

Recent Advances in the Development of Antineoplastic Agents Derived from Natural Products

Through years of evolutionary selection pressures, organisms have developed potent toxins that coincidentally have marked antineoplastic activity. These natural products have been vital for the development of multiagent treatment regimens currently employed in cancer chemotherapy, and are used in the treatment of a variety of malignancies. Therefore, this review catalogs recent advances in natural product-based drug discovery via the examination of mechanisms of action and available clinical data to highlight the utility of these novel compounds in the burgeoning age of precision medicine. The review also highlights the recent development of antibody-drug conjugates and other immunotoxins, which are capable of delivering highly cytotoxic agents previously deemed too toxic to elicit therapeutic benefit preferentially to neoplastic cells. Finally, the review examines natural products not currently used in the clinic that have novel mechanisms of action, and may serve to supplement current chemotherapeutic protocols.

Emerging formats for next-generation antibody drug conjugates

INTRODUCTION

Antibody drug conjugates now make up a significant fraction of biopharma's oncology pipeline due to great advances in the understanding of the three key components and how they should be optimised together. With this clinical success comes innovation to produce new enabling technologies that can deliver more effective antibody-drug conjugates (ADCs) with a larger therapeutic index.

AREAS COVERED

There are many reviews that discuss the various strategies for ADCs design but the last 5 years or so have witnessed the emergence of a number of different antibody formats compete with the standard whole immunoglobulin. Using published research, patent applications and conference disclosures, the authors review the many antibody and antibody-like formats, discussing innovations in protein engineering and how these new formats impact on the conjugation strategy and ultimately the performance. The alternative chemistries that are now available offer new linkages, stability profiles, drug:antibody ratio, pharmacokinetics and efficacy. The different sizes being considered promise to address issues, such as tumour penetration, circulatory half-life and side-effects.

EXPERT OPINION

ADCs are at the beginning of the next stage in their evolution and as these newer formats are developed and examined in the clinic, we will discover if the predicted features have a clinical benefit. From the commercial activity, it is envisaged that smaller or fragment-based ADCs will expand oncological applications.

The epidemiology and targeted therapies for relapsed and refractory CD30+ lymphomas

BACKGROUND

Hodgkin lymphoma (HL) and systemic anaplastic large cell lymphoma (sALCL) both have consistent expression of CD30, a cytokine receptor that is expressed by activated T and B cells but is largely absent from normal tissue.

METHODS

A literature search was conducted via PubMed, Google Scholar, and UpToDate to identify relevant peer-reviewed original research or review articles on HL, sALCL, and CD30 targeted therapies.

RESULTS

These lymphomas are both more common among males, young adults and the elderly. Although many patients with HL and sALCL can achieve long-term remission after standard first-line therapy, up to a third of these patients are refractory to or relapse after initial therapy. Among these relapsed/refractory patients, many experience disease progression and/or death despite subsequent treatment, and treatment-related adverse events and mortality are not uncommon. To address the need for safer and more effective therapies for these relapsed/refractory patients, researchers have developed therapies that specifically target CD30-expressing cells. Brentuximab vedotin, an antibody-drug conjugate that selectively delivers a toxic microtubule-disrupting agent to malignant cells with CD30 expression, is the first such therapy to be approved in the US and Europe. In clinical trials, brentuximab vedotin has demonstrated efficacy and safety in patients with HL after failure of autologous stem cell transplantation (ASCT), or after failure of at least two prior multi-agent chemotherapy regimens in patients who are not ASCT candidates, and in patients with sALCL after failure of at least one prior multi-agent chemotherapy regimen.

CONCLUSION

HL and sALCL are both CD30+ lymphomas, and therapies like brentuximab vedotin that target cells expressing CD30 hold promise for the treatment of these diseases.

Using the Lessons Learned From the Clinic to Improve the Preclinical Development of Antibody Drug Conjugates

The treatment options for cancer patients include surgery, chemotherapeutics, radiation therapy, antibody therapy and various combinations of these therapies. The challenge with each therapy is finding the balance between maximizing the anti-tumor efficacy while minimizing the dose limiting toxicities. Antibodies, unlike small molecule chemotherapeutics, selectively bind to cell surface tumor antigens and can be used to deliver radionucleotides or small molecule chemotherapeutic drugs directly to the tumor. Advances in antibody engineering, linker chemistry and the identification of potent cytotoxic drugs led to the recent approval of two antibody drug conjugates to treat breast cancer and lymphoma patients. We will discuss how the observations from the clinical development of antibody drug conjugates can guide the preclinical development of the next generation of antibody drug conjugates.

Antibody-drug conjugates—a new wave of cancer drugs

Antibody-drug conjugates (ADCs) consist of cytotoxic drugs covalently linked to monoclonal antibodies directed to antigens differentially overexpressed in tumor cells. These loaded antibodies are expected to selectively deliver lethal cargoes to tumor cells and provide sustained clinical benefit to pre-selected cancer patients while, at the same time, minimizing systemic toxicity. Although on-target adverse events are not completely avoided and the true efficacy of these innovative agents still requires further clarification, proof-of-concept has already been achieved in clinical settings with immunoconjugates containing calicheamicin, auristatin or maytansine-based cytotoxic payloads. In this present article we review the characteristics of the preceding cytotoxic platforms and their chemical conjugation approaches.

Immunologic pathomechanism of Hodgkin's lymphoma

Hodgkin's lymphoma is a lymphoid malignancy of the immune system. The pathognomonic Hodgkin and Reed-Sternberg cells (HRS) are derived mainly from monoclonal, preapoptotic B cells, and they carry rearranged, somatically mutated immunoglobulin heavy chains. In an appropriate microenvironment, HRS cells escape from apoptosis by several mechanisms, including single mutations, aberrant signaling pathways. Eventually, weakened immune surveillance leads to uncontrolled, disproportional B cell proliferation. This review summarizes the latest findings on the pathogenesis of Hodgkin lymphoma, with a special emphasis on immunologic processes, and depicts current and future immunotherapeutic regimens, which improve treatment outcomes and reduce late toxicities.

Treatment challenges in the management of relapsed or refractory non-Hodgkin's lymphoma - novel and emerging therapies

Over the last few decades, advances in immunochemotherapy have led to dramatic improvement in the prognosis of non-Hodgkin's lymphoma (NHL). Despite these advances, relapsed and refractory disease represents a major treatment challenge. For both aggressive and indolent subtypes of NHL, there is no standard of care for salvage regimens, with prognosis after relapse remaining relatively poor. Nevertheless, there are multiple emerging classes of targeted therapies for relapsed/refractory disease, including monoclonal antibodies, antibody- drug conjugates, radioimmunotherapy, small-molecule inhibitors of cell-growth pathways, and novel chemotherapy agents. This review will discuss treatment challenges of NHL, current available salvage regimens for relapsed/refractory NHL, and the safety and efficacy of novel emerging therapies.