Field Of Antibody-drug Conjugates Research Articles

Design and Evaluation of ZD06519, a Novel Camptothecin Payload for Antibody Drug Conjugates.

In recent years, the field of antibody drug conjugates (ADC) has seen a resurgence, largely driven by the clinical benefit observed in patients treated with ADCs incorporating camptothecin-based topoisomerase I inhibitor payloads. Herein, we present the development of a novel camptothecin ZD06519 (FD1), which has been specifically designed for its application as an ADC payload. A panel of camptothecin analogs with different substituents at the C-7 and C-10 positions of the camptothecin core was prepared and tested in vitro. Selected compounds spanning a range of potency and hydrophilicity were elaborated into drug-linkers, conjugated to trastuzumab, and evaluated in vitro and in vivo. ZD06519 was selected on the basis of its favorable properties as a free molecule and as an antibody conjugate, which include moderate free payload potency (∼1 nmol/L), low hydrophobicity, strong bystander activity, robust plasma stability, and high-monomeric ADC content. When conjugated to different antibodies using a clinically validated MC-GGFG-based linker, ZD06519 demonstrated impressive efficacy in multiple cell line-derived xenograft models and noteworthy tolerability in healthy mice, rats, and non-human primates.

Analyzing Tumor and Tissue Distribution of Target Antigen Specific Therapeutic Antibody.

Monoclonal antibodies are high affinity multifunctional drugs that work by variable independent mechanisms to eliminate cancer cells. Over the last few decades, the field of antibody-drug conjugates, bispecific antibodies, chimeric antigen receptors (CAR) and cancer immunotherapy has emerged as the most promising area of basic and therapeutic investigations. With numerous successful human trials targeting immune checkpoint receptors and CAR-T cells in leukemia and melanoma at a breakthrough pace, it is highly exciting times for oncologic therapeutics derived from variations of antibody engineering. Regrettably, a significantly large numbers of antibody and CAR based therapeutics have also proven disappointing in human trials of solid cancers because of the limited availability of immune effector cells in the tumor bed. Importantly, nonspecific distribution of therapeutic antibodies in tissues other than tumors also contribute to the lack of clinical efficacy, associated toxicity and clinical failure. As faithful translation of preclinical studies into human clinical trails are highly relied on mice tumor xenograft efficacy and safety studies, here we highlight a method to test the tumor and general tissue distribution of therapeutic antibodies. This is achieved by labeling the protein-A purified antibody with near Infrared fluorescent dye followed by live imaging of tumor bearing mice.

Systemic therapy for metastatic urothelial carcinoma - Current status and what comes after checkpoint inhibitors?

The increasing knowledge of the influence of the immune system on tumour development and progression has fundamentally changed our understanding of tumour biology in recent years. While the available treatment options for patients with metastatic urothelial carcinoma of the urinary bladder have hardly improved over decades, the advent of immune checkpoint inhibitors has caused major changes in the corresponding treatment landscape.Although cisplatin-based combination therapies remain the main element, additional effective treatment options now exist with the PD-(L)-1 inhibitors atezolizumab, pembrolizumab and nivolumab, which have been approved in Europe. A remarkable long-term response is balanced by the occurrence of occasionally severe immune-mediated side effects and an overall low response rate of approximately 25 %. A large number of current clinical trials therefore address possible combinatory approaches in order to make optimal use of possible synergisms and additive effects of the substances available to date, taking into account an acceptable side effect profile. In addition, many new therapeutic approaches are also being tested in clinical trials. In this context, developments in the field of antibody-drug conjugates and FGFR inhibitors with regards to the very recent FDA approvals are particularly noteworthy.The present review provides an overview of currently available treatment options in metastatic urothelial carcinoma of the bladder and especially focuses on future therapeutic approaches based on current clinical trials.

Dyne launches for antibody-oligo conjugates

The hundreds of individual muscles in the human body have long vexed drug developers trying to devise therapies that restore strength to people with genetic muscle diseases. Oligonucleotides designed to patch or block the broken genes that characterize these conditions don’t do a very good job of navigating to muscles on their own. That’s led drug companies to douse patients with high concentrations of oligonucleotide therapies, hoping that enough of the molecules will make their way into muscle. The results have been marginal. To solve that problem, a start-up called Dyne Therapeutics has raised $50 million in series A financing to develop antibody-oligo conjugates that shuttle oligo therapies into muscle cells. The idea takes a play from the antibody-drug conjugate field, where toxic anticancer drugs are attached to tumor-homing antibodies to ensure that the drugs exert their potent effects solely on cancer cells. “When you deliver a naked oligo, very

Safety and Tolerability of Antibody-Drug Conjugates in Cancer.

Antibody-drug conjugates are monoclonal antibodies attached to biologically active drugs through chemical linkers that deliver and release cytotoxic agents at the tumor site, reducing the likelihood of systemic exposure and therefore toxicity. Currently, there are about 110 ongoing studies implementing antibody-drug conjugates in the treatment of multiple human malignancies. Antibody-drug conjugates carry a feature of the specificity of a monoclonal antibody and the anti-neoplastic potential of a cytotoxin. The first antibody-drug conjugate was approved in 2001, and the field of antibody-drug conjugates has expanded since then with three more antibody-drug conjugates being added to the market. The complex structure of the antibody-drug conjugate poses a challenge in designing a clinically adequate molecule. Antibody-drug conjugates are usually well tolerated with some predictable adverse reactions, as well as new medical issues, that need careful approach. This review provides an outline of the current status of the efficacy and safety of antibody-drug conjugates in malignant diseases.

Targeted Delivery of Auristatin-Modified Toxins to Pancreatic Cancer Using Aptamers.

Pancreatic cancer is one of the most lethal malignancies. Treatment with the first-line agent, gemcitabine, is often unsuccessful because it, like other traditional chemotherapeutic agents, is non-specific, resulting in off-target effects that necessitate administration of subcurative doses. Alternatively, monomethyl auristatin E (MMAE) and monomethyl auristatin F (MMAF) are highly toxic small molecules that require ligand-targeted delivery. MMAE has already received FDA approval as a component of an anti-CD30 antibody-drug conjugate, brentuximab vedotin. However, in contrast to antibodies, aptamers have distinct advantages. They are chemicals, which allows them to be produced synthetically and facilitates the rapid development of diagnostics and therapeutics with clinical applicability. In addition, their small size allows for enhanced tissue distribution and rapid systemic clearance. Here, we assayed the toxicity of MMAE and MMAF conjugated to an anti-transferrin receptor aptamer, Waz, and an anti-epidermal growth factor receptor aptamer, E07, on the pancreatic cancer cell lines Panc-1, MIA PaCa-2, and BxPC3. In vitro, our results indicate that these aptamers are a viable option for the targeted delivery of toxic payloads to pancreatic cancer cells.

Antibody Labeling with Fluorescent Dyes Using Magnetic Protein A and Protein G Beads.

Antibodies labeled with small molecules like fluorescent dyes, cytotoxic drugs, and radioactive tracers are essential tools in biomedical research, immunodiagnostics and more recently as therapeutic agents. Traditional methods for labeling antibodies with small molecules require purified antibodies at relatively high concentration, involve multiple dialysis steps and have limited throughput. However, several applications, including the field of Antibody Drug Conjugates (ADCs), will benefit from new methods that will allow labeling of antibodies directly from cell media. Such methods may allow antibodies to be screened in biologically relevant assays, for example, the receptor-mediated antibody internalization assay in the case of ADCs. Here, we describe a method (on-bead method) that enables labeling of small amounts of antibodies directly from cell media. This approach utilizes high capacity magnetic Protein A and Protein G affinity beads to capture antibodies from the cell media followed by labeling with small molecules using either amine or thiol chemistry and subsequent elution of the labeled antibodies. Taking fluorescent dyes as surrogates for small molecules, we demonstrate the on-bead labeling of three different mouse antibodies directly from cell media using both amine and thiol labeling chemistry. The high binding affinity of antibodies to Protein A and Protein G ensures high recoveries as well as high purity of the labeled antibodies. In addition, use of magnetic beads allows multiple samples to be handled manually, thereby significantly improving labeling throughput.

Design and Synthesis of Tesirine, a Clinical Antibody-Drug Conjugate Pyrrolobenzodiazepine Dimer Payload.

Pyrrolobenzodiazepine dimers are an emerging class of warhead in the field of antibody-drug conjugates (ADCs). Tesirine (SG3249) was designed to combine potent antitumor activity with desirable physicochemical properties such as favorable hydrophobicity and improved conjugation characteristics. One of the reactive imines was capped with a cathepsin B-cleavable valine-alanine linker. A robust synthetic route was developed to allow the production of tesirine on clinical scale, employing a flexible, convergent strategy. Tesirine was evaluated in vitro both in stochastic and engineered ADC constructs and was confirmed as a potent and versatile payload. The conjugation of tesirine to anti-DLL3 rovalpituzumab has resulted in rovalpituzumab-tesirine (Rova-T), currently under evaluation for the treatment of small cell lung cancer.

Abstract 822: Thienoindoles, a novel class of DNA minor groove alkylating agents highly suited for the generation of novel antibody drug conjugates (ADCs)

Abstract The rapidly growing field of Antibody-Drug Conjugates (ADCs) has recently spurred the study of novel drug payloads. In particular, much interest has been paid to the identification of novel cytotoxic agents, which differ in mechanism from anti-tubulin agents, currently the most commonly employed class of drug for ADC coupling. Novel drug payloads for ADC-based therapy should thus ideally possess highly potent cytotoxic activity with a diverse mechanism from tubulin agents, as well as physicochemical properties, which facilitate coupling to antibodies. Duocarmycins are a widely-described class of DNA minor groove binding alkylating agents, examples of which can exhibit picomolar activity against human tumor cell lines, as well as high activity in preclinical tumor models. The clinical development of duocarmycins as drugs in their own right has however been hampered by an extremely limited therapeutic window. Duocarmycins also typically exhibit poor physicochemical profiles, most importantly generally possessing limited aqueous solubility and a propensity to induce protein aggregation, which renders these molecules poorly tractable as optimal ADC payloads. Based on the premise that opportune modification of the duocarmycin scaffold could lead to the discovery of compounds better suited to antibody conjugation, we describe the identification and related proof of concept studies for a novel chemical series based on a proprietary thienoindole scaffold, characterized both by potent antitumor activity and by physicochemical properties that are highly compatible with deployment as antibody payloads. Extensive in vitro profiling within the thienoindole series led to selection of potent cytotoxic compounds suitable for test conjugation to humanized monoclonal antibodies, which were then submitted to in vitro/in vivo profiling. Typically, average drug/antibody ratios (DARs) of 4 could readily be achieved without induction of antibody aggregation/precipitation and without affecting natural antibody-ligand affinity. Efficacy and mechanism of action studies were carried out for thienoindole-ADCs prepared with trastuzumab and with rituximab showing target driven effects in Her2 positive vs. negative breast cancer cell lines and against CD20 positive vs. negative hematological cell lines. PK data indicated long, essentially unaffected plasma half life of our novel ADCs in the mouse. In vivo efficacy studies in the Her2-positive HCC1954 human breast cancer model showed complete tumor regression in mice treated with trastuzumab-ADC with no effects on body weight gain, while unarmed trastuzumab and armed control antibody had little and no effect, respectively. Citation Format: Barbara Valsasina, Fabio Gasparri, Italo Beria, Nicoletta Colombo, Paolo Orsini, Rita Perego, Simona Rizzi, Ulisse Cucchi, Clara Albanese, Aurelio Marsiglio, Ivan Fraietta, Marina Ciomei, Sabrina Cribioli, Carlo Visco, Eduard R. Felder, Antonella Isacchi, Enrico A. Pesenti, Arturo Galvani, Daniele Donati, Michele Caruso. Thienoindoles, a novel class of DNA minor groove alkylating agents highly suited for the generation of novel antibody drug conjugates (ADCs). [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 822. doi:10.1158/1538-7445.AM2014-822

Antibody–drug conjugates: targeted drug delivery for cancer

The antibody-drug conjugate field has made significant progress recently owing to careful optimization of several parameters, including mAb specificity, drug potency, linker technology, and the stoichiometry and placement of conjugated drugs. The underlying reason for this has been obtained in pre-clinical biodistribution and pharmacokinetics studies showing that targeted delivery leads to high intratumoral free drug concentrations, while non-target tissues are largely spared from chemotherapeutic exposure. Recent developments in the field have led to an increase in the number of ADCs being tested clinically, with 3 in late stage clinical trials: brentuximab vedotin (also referred to as SGN-35) for Hodgkin lymphoma; Trastuzumab-DM1 for breast cancer; and Inotuzumab ozogamicin for non-Hodgkin lymphoma. This review highlights the recent pre-clinical and clinical advances that have been made.