Abatacept: a novel treatment for rheumatoid arthritis

Breaking the crosstalk of the cellular tumorigenic network: Hypothesis for addressing resistances to targeted therapies in advanced NSCLC

In the light of current treatment developments for non-small cell lung cancer (NSCLC), the idea of a plastic cellular tumorigenic network bound by key paracrine signaling pathways mediating resistances to targeted therapies is brought forward. Based on a review of available preclinical and clinical data in NSCLC combinational approaches to address drivers of this network with marketed drugs are discussed. Five criteria for selecting drug combination regimens aiming at its disruption and thereby overcoming resistances are postulated.

Lack of Impact of Cytotoxic T-Lymphocyte Antigen 4 Gene Exon 1 Polymorphism on Susceptibility to or Clinical Course of Egyptian Childhood Immune Thrombocytopenic Purpura

Dysfunctional T-lymphocyte immunity plays an important role in the pathophysiology of immune thrombocytopenic purpura (ITP). Cytotoxic T-lymphocyte antigen 4 ( CTLA-4)—a surface marker expressed on T regulatory cells and activated T lymphocytes—is a negative modulator of T-cell responses. Polymorphisms of the CTLA-4 may alter the level of antigen expression and hence may influence immune regulation. The study aimed to evaluate the possible contribution of CTLA-4 exon 1 49 A>G polymorphism to the pathogenesis of ITP and its relation to age of disease onset, clinical course, and response to therapy. Genotyping of CTLA-4 exon 1 49 A>G was performed in 100 pediatric patients with ITP and 259 healthy individuals by polymerase chain reaction–restricted fragment length polymorphism. No significant differences existed in genotype or allele distributions between patients and controls for the studied polymorphism. Comparable genotypes and allele frequencies were obtained between the 2 groups after their stratification by age of disease onset, clinical course, or response to therapy. In conclusion, CTLA-4 exon 1 49 A>G polymorphism is not associated with susceptibility to ITP in the Egyptian population; neither it affects the clinical picture of the disease.

Pharmacokinetics of recombinant bifunctional fusion proteins

INTRODUCTION

The development of biotechnology has enabled the creation of various recombinant fusion proteins as a new class of biotherapeutics. The uniqueness of fusion proteins lies in their ability to fuse two or more protein domains, providing vast opportunities to generate novel combinations of functions. Pharmacokinetic (PK) studies, which are critical components in preclinical and clinical drug development, have not been fully explored for fusion proteins. The lack of general PK models and study guidelines has become a bottleneck for translation of fusion proteins from basic research to the clinic.

AREAS COVERED

This article reviews the current status of PK studies for fusion proteins, covering the processes that affect PK. According to their PK properties, a classification of fusion proteins is suggested along with examples from the clinic or under development. Current limitations and future perspectives for PK of fusion proteins are also discussed.

EXPERT OPINION

A PK model for bifunctional fusion proteins is presented to highlight the importance of mechanistic studies for a thorough understanding of the PK properties of fusion proteins. The model suggests investigating the receptor binding and subsequent intracellular disposition of individual domains, which can have dramatic impact on the PK of fusion proteins.

Critical appraisal of efficacy and safety of abatacept in the treatment of refractory rheumatoid arthritis

Rheumatoid arthritis is a chronic, progressive, autoimmune disease that leads to significant disability and premature mortality. Various treatment options are available, but the foundation of treatment includes nonbiologic and biologic disease-modifying antirheumatic drugs. The incidence of patients with rheumatoid arthritis refractory to first-line agents is estimated to be at least 20%. Abatacept, a T cell costimulation modulator, is the first agent to interfere with full T cell activation by competing with CD28 for binding of CD80 and CD86, which results in decreased secretion of proinflammatory cytokines and autoantibody production. Current American College of Rheumatology treatment guidelines recommend abatacept for patients with at least moderate disease activity and a poor prognosis demonstrating an inadequate response to other agents. Several key Phase III trials have been conducted to evaluate the efficacy and safety of abatacept in patients with an inadequate response to methotrexate or anti-tumor necrosis factor alpha therapy. Response rates in all trials showed statistically significant improvements compared with placebo according to American College of Rheumatology criteria for disease improvement. The most common adverse event report in patients receiving abatacept was infection; however, the frequency of adverse events was similar to placebo. Abatacept is a safe and effective rheumatoid arthritis treatment for patients with an inadequate response to methotrexate or anti-tumor necrosis factor alpha therapy.