Immunology and Biotherapies

Abstract

The concept of using immunotherapy to treat melanoma has existed for decades. The rationale comes from the knowledge that many patients with melanoma have endogenous immune responses against their tumor cells and clinically meaningful tumor regression can be achieved in a minority of patients using cytokines such as interleukin-2 and adoptive cellular therapy. In the last 5 years there has been a revolution in the clinical management of melanoma in large measure based on the development of antibodies that influence T cell regulatory pathways by overcoming checkpoint inhibition and providing co-stimulation, either of which results in significantly more effective immune-mediated tumor destruction. This review will describe the pre-clinical and clinical application of antagonistic antibodies targeting the T-cell checkpoints cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed death 1 (PD-1), and agonistic antibodies targeting the costimulatory pathways OX40 and 4-1BB. Recent progress and opportunities for future investigation of combination antibody therapy will be described.

Ektomun® is a member of the highly innovative, validated family of Triomab® antibodies. It combines the halves of two distinct full-size antibodies, a GD2-specific mouse antibody and a T -cell specific rat antibody, in one molecule.

 

GD2 is a clinically validated tumor target opening many potential applications for ektomun®. It is broadly present in tumors of neuroectodermal origin, including small cell lung cancer (SCLC), melanoma, neuroblastoma and glioblastoma. In healthy tissues, however, GD2 expression is strictly limited to very few, distinct cell types.

 

Due to its trifunctional design, ektomun® can simultaneously bind to GD2, expressed by  tumor cells, to a T-cell and, via its Fc-region, to an accessory cell of the innate immune system, as e.g. macrophages, dendritic or NK cells.

 

The resulting tri-cell-complex triggers multiple immune mechanisms at the same time.  Not only are tumor cells specifically and potently destroyed, but a long-lasting anti-tumor immunity is also induced – an effect that can otherwise only be achieved through vaccination.

Learn more about KB001-A study to prevent or treat a common opportunistic gram negative bacterium, Pseudomonas aeruginosa (Pa)

Highlights

 

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Engineering of smaller antibody scaffolds can overcome the limitations of full-size antibodies.

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This review focuses on engineered IgG1 Fc based antibody fragments and domains as novel scaffolds.

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The Fc based binders are promising candidate therapeutics with small size and long half-lives.

 

Abstract

Therapeutic monoclonal antibodies (mAbs) have been successful for the therapy of a number of diseases mostly cancer and immune disorders. However, the vast majority of mAbs approved for clinical use are full size, typically in IgG1 format. These mAbs may exhibit relatively poor tissue penetration and restricted epitope access due to their large size. A promising solution to this fundamental limitation is the engineering of smaller scaffolds based on the IgG1 Fc region. These scaffolds can be used for the generation of libraries of mutants from which high-affinity binders can be selected. Comprised of the CH2 and CH3 domains, the Fc region is important not only for the antibody effector function but also for its long half-life. This review focuses on engineered Fc based antibody fragments and domains including native (dimeric) Fc and monomeric Fc as well as CH2 and monomeric CH3, and their use as novel scaffolds and binders. The Fc based binders are promising candidate therapeutics with optimized half-life, enhanced tissue penetration and access to sterically restricted binding sites resulting in an increased therapeutic efficacy. This article is part of a Special Issue entitled: Recent advances in molecular engineering of antibody.

Interleukin-2 receptor α chain (CD25) is overexpressed in human T-cell leukemia virus 1 associated adult T-cell leukemia/lymphoma (ATL). Daclizumab a humanized monoclonal antibody blocks IL-2 binding by recognizing the interleukin-2 receptor α chain (CD25). We conducted a phase I/II trial of daclizumab in 34 patients with ATL. Saturation of surface CD25 on circulating ATL cells was achieved at all doses; however saturation on ATL cells in lymph nodes required 8mg/kg. Up to 8mg/kg of daclizumab administered every 3weeks was well tolerated. No responses were observed in 18 patients with acute or lymphoma ATL; however, 6 partial responses were observed in 16 chronic and smoldering ATL patients. The pharmacokinetics/pharmacodynamics of daclizumab suggest that high-dose daclizumab would be more effective than low-dose daclizumab in treatment of lymphoid malignancies and autoimmune diseases (e.g., multiple sclerosis) since high-dose daclizumab is required to saturate IL-2R alpha in extravascular sites.

Highlights

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Interleukin-2 receptor alpha chain (CD25) is overexpressed by ATL leukemia cells.

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Daclizumab a humanized monoclonal antibody blocks IL-2 binding to CD25.

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8 mg/kg of daclizumab is required to get ≥ 95% saturation of CD25 in lymph nodes.

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Partial responses were observed in patients with chronic and smoldering ATL.

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The study provides a rationale for high-dose treatment in lymphoid malignancies.

Affimed develops TandAbs and Trispecific Abs for substantially increasing the efficacy and extend the therapeutic window by three proprietary platforms

Abstract

Many proteins of interest in basic biology, translational research studies and for clinical targeting in diseases reside inside the cell and function by interacting with other macromolecules. Protein complexes control basic processes such as development and cell division but also abnormal cell growth when mutations occur such as found in cancer. Interfering with protein–protein interactions is an important aspiration in both basic and disease biology but small molecule inhibitors have been difficult and expensive to isolate. Recently, we have adapted molecular biology techniques to develop a simple set of protocols for isolation of high affinity antibody fragments (in the form of single VH domains) that function within the reducing environment of higher organism cells and can bind to their target molecules. The method called Intracellular Antibody Capture (IAC) has been used to develop inhibitory anti-RAS and anti-LMO2 single domains that have been used for target validation of these antigens in pre-clinical cancer models and illustrate the efficacy of the IAC approach to generation of drug surrogates. Future use of inhibitory VH antibody fragments as drugs in their own right (we term these macrodrugs to distinguish them from small molecule drugs) requires their delivery to target cells in vivo but they can also be templates for small molecule drug development that emulate the binding sites of the antibody fragments. This article is part of a Special Issue entitled: Recent advances in molecular engineering of antibody.

An evaluation of risk factors for major adverse #cardiovascular events during #tocilizumab therapy http://t.co/EymLTiXiv1 #rheum

Abstract

Objective. To explore associations of baseline and on-treatment lipid levels, inflammation, and rheumatoid arthritis (RA) disease activity with risk for major adverse cardiovascular events (MACE) in tocilizumab-treated RA patients.

Methods. In retrospective post hoc analyses, data were pooled from 3986 adults with moderate to severe RA administered ≥1 dose of tocilizumab 4 or 8 mg/kg intravenously every 4 weeks in randomized controlled trials and extension studies. Cox proportional hazards modeling was used to evaluate associations among baseline characteristics and posttreatment initiation variables (week 24) and change from baseline to week 24 disease activity and laboratory values, with risk for future MACE during extended follow-up.

Results. There were 50 independently adjudicated cases of MACE during 14,683 patient-years (PY) of follow-up (0.34 MACE/100 PY). At baseline, age, history of cardiac disorders, disease activity score using 28 joints (DAS28), and total cholesterol/high-density lipoprotein ratio were independently (P<0.05 for all) associated with MACE in multivariable models. On treatment, higher DAS28 scores and swollen and tender joint counts at week 24 were associated with future MACE. In separate models, greater reductions in DAS28 score and joint counts from baseline to week 24 were inversely associated with future MACE; changes in lipid parameters were not statistically significantly associated with risk for MACE.

Conclusion. As in the general population, an association was observed between baseline total cholesterol/high-density lipoprotein ratio and increased risk for MACE. Risk for on-treatment MACE, however, was found to be associated with control of disease activity but not lipid changes. Larger studies are needed to confirm these findings. © 2014 American College of Rheumatology.

Amgen, Inc. (NASDAQ:AMGN) has filed a Biologics License Application with the FDA for a new class of cholesterol-fighting drugs. It is competing with Sanofi SA (ADR) (NYSE:SNY) to be the first to tap into the $10 billion market.

Engineered T cell CAR therapy

A revolution is taking place in the field of adoptive immunotherapy, where T cells armed with a Chimeric Antigen Receptor (CAR) are being used to fight cancerous cells. Genome engineering is at the heart of this revolution. This groundbreaking technology relies mainly on the use of engineered nucleases and makes it possible to modify the genome of the T cell to give it new properties. Specifically, the engineered T cell can be transformed into an allogeneic product, or it can resist existing cancer treatments or even overcome checkpoint inhibition. Genome engineering is regarded as one of the most important breakthroughs of recent years, and is about to revolutionize immunotherapy. 

Decades of research have shown that it is possible to improve the ability of T cells to fight diseases by genome engineering. For example, T cells can be engineered by adding a new gene (called a chimeric antigen receptor or CAR) that will boost their ability to recognize and destroy cancer cells. Another possibility for T cells is to inactivate an existing gene that damages the immune response.

The possibilities provided by T cell genome engineering are endless. Very sophisticated strategies can be designed at will to open the door for a new era of treatments in indications such as infectious diseases, autoimmune diseases, and cancer.

Chimeric Antigen Receptors (CARs) are artificial molecules that, when present at the surface of immune effector cells, will enable them to recognize a desired protein (antigen) and trigger the killing of cells harboring this antigen at their surface (target cells).

These receptors are becoming one of the most promising approaches to fight cancer, through the development of adoptive cell transfer therapies. Indeed, immune cells (most usually T-lymphocytes) can be engineered to express a CAR able to recognize proteins present at the surface of cancer cells. Upon cell-to-cell contact between effector and targeted cells, antigen recognition will activate the effectors, giving them the signal to attack their targets, and leading ultimately to the killing of cancer cells.

CARs are constructed by assembling domains from different proteins, each of which enables the chimeric molecule to carry out specific functions. The most common CAR architecture comprises an extracellular domain containing a region that recognizes the targeted antigen and a spacer region that links it to the transmembrane domain (the part of the protein that spans the cellular membrane). This is then followed by an intracellular domain, responsible for transmitting an activation signal to the cell upon antigen recognition, causing the CAR-engineered cell to attack the tumor cell.

The target-binding moiety is usually derived from an antibody, while the intracellular portion can include, besides the domain leading to cell activation and cytotoxic response, one or more domains from co-stimulatory receptor proteins that could enhance the proliferative capacity and survival of the “therapeutic” cells.

Cellectis is currently developing a collection of CARs targeting antigens present on cells from various types of cancer, as well as a proprietary multi-chain architecture of these artificial receptors, aiming to further increase the efficacy of adoptive cell therapies in the future.

CELLECTIS’ UCART19 RECEIVES ADVANCED-THERAPY MEDICINAL PRODUCT CLASSIFICATION FROM EMAJune 23, 2014

READ MORE READ THE PRESS RELEASEPFIZER AND CELLECTIS ENTER INTO GLOBAL STRATEGIC CANCER IMMUNOTHERAPY COLLABORATIONJune 18, 2014