Antibody drug conjugates: Progress, pitfalls, and promises

Smart Nanomaterials in Cancer Theranostics: Challenges and Opportunities

Cancer is ranked as the second leading cause of death globally. Traditional cancer therapies including chemotherapy are flawed, with off-target and on-target toxicities on the normal cells, requiring newer strategies to improve cell selective targeting. The application of nanomaterial has been extensively studied and explored as chemical biology tools in cancer theranostics. It shows greater applications toward stability, biocompatibility, and increased cell permeability, resulting in precise targeting, and mitigating the shortcomings of traditional cancer therapies. The nanoplatform offers an exciting opportunity to gain targeting strategies and multifunctionality. The advent of nanotechnology, in particular the development of smart nanomaterials, has transformed cancer diagnosis and treatment. The large surface area of nanoparticles is enough to encapsulate many molecules and the ability to functionalize with various biosubstrates such as DNA, RNA, aptamers, and antibodies, which helps in theranostic action. Comparatively, biologically derived nanomaterials perceive advantages over the nanomaterials produced by conventional methods in terms of economy, ease of production, and reduced toxicity. The present review summarizes various techniques in cancer theranostics and emphasizes the applications of smart nanomaterials (such as organic nanoparticles (NPs), inorganic NPs, and carbon-based NPs). We also critically discussed the advantages and challenges impeding their translation in cancer treatment and diagnostic applications. This review concludes that the use of smart nanomaterials could significantly improve cancer theranostics and will facilitate new dimensions for tumor detection and therapy.

Lung cancer immunotherapy: progress, pitfalls, and promises

Lung cancer is the primary cause of mortality in the United States and around the globe. Therapeutic options for lung cancer treatment include surgery, radiation therapy, chemotherapy, and targeted drug therapy. Medical management is often associated with the development of treatment resistance leading to relapse. Immunotherapy is profoundly altering the approach to cancer treatment owing to its tolerable safety profile, sustained therapeutic response due to immunological memory generation, and effectiveness across a broad patient population. Different tumor-specific vaccination strategies are gaining ground in the treatment of lung cancer. Recent advances in adoptive cell therapy (CAR T, TCR, TIL), the associated clinical trials on lung cancer, and associated hurdles are discussed in this review. Recent trials on lung cancer patients (without a targetable oncogenic driver alteration) reveal significant and sustained responses when treated with programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) checkpoint blockade immunotherapies. Accumulating evidence indicates that a loss of effective anti-tumor immunity is associated with lung tumor evolution. Therapeutic cancer vaccines combined with immune checkpoint inhibitors (ICI) can achieve better therapeutic effects. To this end, the present article encompasses a detailed overview of the recent developments in the immunotherapeutic landscape in targeting small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). Additionally, the review also explores the implication of nanomedicine in lung cancer immunotherapy as well as the combinatorial application of traditional therapy along with immunotherapy regimens. Finally, ongoing clinical trials, significant obstacles, and the future outlook of this treatment strategy are also highlighted to boost further research in the field.

Targeted Delivery of Chemotherapeutic Agents for Osteosarcoma Treatment

Since osteosarcoma (OS) is an aggressive bone cancer with unknown molecular pathways of etiology and pathophysiology, improving patient survival has long been a challenge. The conventional therapy is a complex multidisciplinary management that include radiotherapy, chemotherapy which followed by surgery and then post-operative adjuvant chemotherapy. However, they have severe side effects because the majority of the medicines used have just a minor selectivity for malignant tissue. As a result, treating tumor cells specifically without damaging healthy tissue is currently a primary goal in OS therapy. The coupling of chemotherapeutic drugs with targeting ligands is a unique therapy method for OS that, by active targeting, can overcome the aforementioned hurdles. This review focuses on advances in ligands and chemotherapeutic agents employed in targeted delivery to improve the capacity of active targeting and provide some insight into future therapeutic research for OS.

Factors influencing the choice of monoclonal antibodies for antibody-drug conjugates

In antibody-drug conjugates (ADCs), monoclonal antibodies (mAbs) act as carriers for a cytotoxic payload providing the therapy with targeted action against cells expressing a target cell surface antigen. An appropriate choice of mAb is crucial to developing a successful ADC for clinical development. However, problems such as immunogenicity, poor pharmacokinetic (PK) and pharmacodynamic (PD) profiles and variable drug-antibody ratios (DARs) plague ADCs. In this review, we detail recent mAb-based innovations and factors that should be considered to overcome these problems to achieve a new generation of more effective ADC therapeutics.

Targeting a Radiosensitizing Antibody-Drug Conjugate to a Radiation-Inducible Antigen

PURPOSE

We recently discovered that anti-TIP1 antibody activates endocytosis in cancer cells, which facilitates retention of antibody and dissociation of a conjugated drug. To improve the pharmacokinetics and cancer specificity of radiosensitizing drugs, we utilized antibody-drug conjugates (ADCs) that bind specifically to radiation-inducible antigen, TIP1, on non-small cell lung cancer (NSCLC). This approach exploits the long circulation time of antibodies to deliver a radiosensitizing drug to cancer each day during radiotherapy.

EXPERIMENTAL DESIGN

Antibodies to TIP1 were prioritized based on affinity, cancer-specific binding, and internalization. The lead antibody, 7H5, was conjugated with a cytotoxic drug MMAE because of its ability to radiosensitize cancer. Cytotoxicity, colony formation, and tumor growth studies were performed with 7H5-VcMMAE in combination with radiation.

RESULTS

7H5 showed a high affinity to recombinant TIP1 protein and radiation-inducible TIP1 on the cancer cell surface. 7H5 undergoes endocytosis in NSCLC cells in vitro. We obtained an average drug-to-antibody ratio (DAR) of 4.25 for 7H5-VcMMAE. A 70% reduction in viable cells was observed following 7H5-VcMMAE treatment compared with 7H5 alone in both A549 and H1299 cells. 7H5-VcMMAE sensitized NSCLC cells to radiation, thereby significantly decreasing the surviving fraction. The ADC combined with radiation showed a prolonged delay in tumor growth and improved survival in A549 and H1299 tumor models.

CONCLUSIONS

Targeting radiation-inducible TIP1 with a radiosensitizing ADC is a promising strategy to enhance the therapeutic efficacy of NSCLC. This novel approach of targeting with ADCs to radiation-inducible antigens will lead to clinical trials in lung cancer patients treated with radiotherapy.

Anti-tumour drugs of marine origin currently at various stages of clinical trials (review)

Oncological diseases for a long time have remained one of the most significant health problems of modern society, which causes great losses in its labour and vital potential. Contemporary oncology still faces unsolved issues as insufficient efficacy of treatment of progressing and metastatic cancer, chemoresistance, and side-effects of the traditional therapy which lead to disabilities among or death of a high number of patients. Development of new anti-tumour preparations with a broad range of pharmaceutical properties and low toxicity is becoming increasingly relevant every year. The objective of the study was to provide a review of the recent data about anti-tumour preparations of marine origin currently being at various phases of clinical trials in order to present the biological value of marine organisms – producers of cytotoxic compounds, and the perspectives of their use in modern biomedical technologies. Unlike the synthetic oncological preparations, natural compounds are safer, have broader range of cytotoxic activity, can inhibit the processes of tumour development and metastasis, and at the same time have effects on several etiopathogenic links of carcinogenesis. Currently, practical oncology uses 12 anti-tumour preparations of marine origin (Fludarabine, Cytarabine, Midostaurin, Nelarabine, Eribulin mesylate, Brentuximab vedotin, Trabectedin, Plitidepsin, Enfortumab vedotin, Polatuzumab vedotin, Belantamab mafodotin, Lurbinectedin), 27 substances are at different stages of clinical trials. Contemporary approaches to the treatment of oncological diseases are based on targeted methods such as immune and genetic therapies, antibody-drug conjugates, nanoparticles of biopolymers, and metals. All those methods employ bioactive compounds of marine origin. Numerous literature data from recent years indicate heightened attention to the marine pharmacology and the high potential of marine organisms for the biomedicinal and pharmaceutic industries.

Antibody-drug conjugates for previously treated aggressive lymphomas: focus on polatuzumab vedotin

INTRODUCTION

Antibody-drug conjugates (ADCs) are immunoconjugates and comprise a monoclonal antibody that is chemically attached to a cytotoxic drug (or payload) via a stable chemical linker. Since the approval of the first ADC in 2000, there are now nine different approved agents and over 100 ADCs in the drug-development pipeline.

AREAS COVERED

This review briefly describes the ADCs approved for treatment of lymphoma and their distinguishing factors in terms of target, linker and payload. The clinical implications of the use of ADCs are also considered. Here, we focus on polatuzumab vedotin, an ADC targeted to CD79b, which is approved for the treatment of patients with relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL) who have received at least one (EU approval) or two (US approval) prior therapies and are not eligible for bone marrow transplantation. The characteristics of polatuzumab vedotin are discussed and clinical data are presented. The future of polatuzumab vedotin clinical development, and ADCs in general, are also considered.

EXPERT OPINION

ADCs represent a significant advance in the treatment of lymphoma. Polatuzumab vedotin has shown clinical efficacy and a tolerable safety profile in both first-line and R/R DLBCL; future studies are planned to further investigate this ADC.

Recent advances of antibody drug conjugates for clinical applications

Antibody drug conjugates (ADCs) normally compose of a humanized antibody and small molecular drug via a chemical linker. After decades of preclinical and clinical studies, a series of ADCs have been widely used for treating specific tumor types in the clinic such as brentuximab vedotin (Adcetris®) for relapsed Hodgkin's lymphoma and systemic anaplastic large cell lymphoma, gemtuzumab ozogamicin (Mylotarg®) for acute myeloid leukemia, ado-trastuzumab emtansine (Kadcyla®) for HER2-positive metastatic breast cancer, inotuzumab ozogamicin (Besponsa®) and most recently polatuzumab vedotin-piiq (Polivy®) for B cell malignancies. More than eighty ADCs have been investigated in different clinical stages from approximately six hundred clinical trials to date. This review summarizes the key elements of ADCs and highlights recent advances of ADCs, as well as important lessons learned from clinical data, and future directions.

Pharmacokinetics of polatuzumab vedotin in combination with R/G-CHP in patients with B-cell non-Hodgkin lymphoma

Purpose

The phase Ib/II open-label study (NCT01992653) evaluated the antibody-drug conjugate polatuzumab vedotin (pola) plus rituximab/obinutuzumab, cyclophosphamide, doxorubicin, and prednisone (R/G-CHP) as first-line therapy for B-cell non-Hodgkin lymphoma (B-NHL). We report the pharmacokinetics (PK) and drug–drug interaction (DDI) for pola.

Methods

Six or eight cycles of pola 1.0–1.8 mg/kg were administered intravenously every 3 weeks (q3w) with R/G-CHP. Exposures of pola [including antibody-conjugated monomethyl auristatin E (acMMAE) and unconjugated MMAE] and R/G-CHP were assessed by non-compartmental analysis and/or descriptive statistics with cross-cycle comparisons to cycle 1 and/or after multiple cycles. Pola was evaluated as a potential victim and perpetrator of a PK drug–drug interaction with R/G-CHP. Population PK (popPK) analysis assessed the impact of prior treatment status (naïve vs. relapsed/refractory) on pola PK.

Results

Pola PK was similar between treatment arms and independent of line of therapy. Pola PK was dose proportional from 1.0 to 1.8 mg/kg with R/G-CHP. Geometric mean volume of distribution and clearance of acMMAE ranged from 57.3 to 95.6 mL/kg and 12.7 to 18.2 mL/kg/day, respectively. acMMAE exhibited multi-exponential decay (elimination half-life ~ 1 week). Unconjugated MMAE exhibited formation rate-limited kinetics. Exposures of pola with R/G-CHP were similar to those in the absence of CHP; exposures of R/G-CHP in the presence of pola were comparable to those in the absence of pola.

Conclusions

Pola PK was well characterized with no clinically meaningful DDIs with R/G-CHP. Findings are consistent with previous studies of pola + R/G, and support pola + R/G-CHP use in previously untreated diffuse large B-cell lymphoma.

Electronic supplementary material

The online version of this article (10.1007/s00280-020-04054-8) contains supplementary material, which is available to authorized users.

Antibody Conjugates-Recent Advances and Future Innovations

Monoclonal antibodies have evolved from research tools to powerful therapeutics in the past 30 years. Clinical success rates of antibodies have exceeded expectations, resulting in heavy investment in biologics discovery and development in addition to traditional small molecules across the industry. However, protein therapeutics cannot drug targets intracellularly and are limited to soluble and cell-surface antigens. Tremendous strides have been made in antibody discovery, protein engineering, formulation, and delivery devices. These advances continue to push the boundaries of biologics to enable antibody conjugates to take advantage of the target specificity and long half-life from an antibody, while delivering highly potent small molecule drugs. While the "magic bullet" concept produced the first wave of antibody conjugates, these entities were met with limited clinical success. This review summarizes the advances and challenges in the field to date with emphasis on antibody conjugation, linker-payload chemistry, novel payload classes, absorption, distribution, metabolism, and excretion (ADME), and product developability. We discuss lessons learned in the development of oncology antibody conjugates and look towards future innovations enabling other therapeutic indications.

TR1801-ADC: a highly potent cMet antibody-drug conjugate with high activity in patient-derived xenograft models of solid tumors

cMet is a well‐characterized oncogene that is the target of many drugs including small molecule and biologic pathway inhibitors, and, more recently, antibody–drug conjugates (ADCs). However, the clinical benefit from cMet‐targeted therapy has been limited. We developed a novel cMet‐targeted ‘third‐generation’ ADC, TR1801‐ADC, that was optimized at different levels including specificity, stability, toxin–linker, conjugation site, and in vivo efficacy. Our nonagonistic cMet antibody was site‐specifically conjugated to the pyrrolobenzodiazepine (PBD) toxin–linker tesirine and has picomolar activity in cancer cell lines derived from different solid tumors including lung, colorectal, and gastric cancers. The potency of our cMet ADC is independent of MET gene copy number, and its antitumor activity was high not only in high cMet‐expressing cell lines but also in medium‐to‐low cMet cell lines (40 000–90 000 cMet/cell) in which a cMet ADC with tubulin inhibitor payload was considerably less potent. In vivo xenografts with low–medium cMet expression were also very responsive to TR1801‐ADC at a single dose, while a cMet ADC using a tubulin inhibitor showed a substantially reduced efficacy. Furthermore, TR1801‐ADC had excellent efficacy with significant antitumor activity in 90% of tested patient‐derived xenograft models of gastric, colorectal, and head and neck cancers: 7 of 10 gastric models, 4 of 10 colorectal cancer models, and 3 of 10 head and neck cancer models showed complete tumor regression after a single‐dose administration. Altogether, TR1801‐ADC is a new generation cMet ADC with best‐in‐class preclinical efficacy and good tolerability in rats.

Recent Trends of the Bio-Inspired Nanoparticles in Cancer Theranostics

In recent years, various nanomaterials have emerged as an exciting tool in cancer theranostic applications due to their multifunctional property and intrinsic molecular property aiding effective diagnosis, imaging, and successful therapy. However, chemically synthesized nanoparticles have several issues related to the cost, toxicity and effectiveness. In this context, bio-inspired nanoparticles (NPs) held edges over conventionally synthesized nanoparticles due to their low cost, easy synthesis and low toxicity. In this present review article, a detailed overview of the cancer theranostics applications of various bio-inspired has been provided. This includes the recent examples of liposomes, lipid nanoparticles, protein nanoparticles, inorganic nanoparticles, and viral nanoparticles. Finally, challenges and the future scopes of these NPs in cancer therapy and diagnostics applications are highlighted.

Recent Progress in the Theranostics Application of Nanomedicine in Lung Cancer

Lung cancer is one of the leading causes of cancer-related death worldwide. Non-small cell lung cancer (NSCLC) causes around 80% to 90% of deaths. The lack of an early diagnosis and inefficiency in conventional therapies causes poor prognosis and overall survival of lung cancer patients. Recent progress in nanomedicine has encouraged the development of an alternative theranostics strategy using nanotechnology. The interesting physico-chemical properties in the nanoscale have generated immense advantages for nanoparticulate systems for the early detection and active delivery of drugs for a better theranostics strategy for lung cancer. This present review provides a detailed overview of the recent progress in the theranostics application of nanoparticles including liposomes, polymeric, metal and bio-nanoparticles. Further, we summarize the advantages and disadvantages of each approach considering the improvement for the lung cancer theranostics.

Protein-driven nanomedicines in oncotherapy

Proteins are organic macromolecules essential in life but exploited, mainly in recombinant versions, as drugs or vaccine components, among other uses in industry or biomedicine. In oncology, individual proteins or supramolecular complexes have been tailored as small molecular weight drug carriers for passive or active tumor cell-targeted delivery, through the de novo design of appropriate drug stabilizing vehicles, or by generating constructs with different extents of mimesis of natural cell-targeted entities, such as viruses. In most of these approaches, a convenient nanoscale size is achieved through the oligomeric organization of the protein component in the drug conjugate. Among the different taken strategies, highly cytotoxic proteins such as microbial or plant toxins have been conveniently engineered to self-assemble as self-delivered virus-like, nanometric structures, chemically homogeneous that target metastatic cancer stem cells for the destruction of metastasis in absence of any partner vehicle.