iGlarLixi, a titratable once-daily fixed-ratio combination of basal insulin and lixisenatide for intensifying type 2 diabetes management for patients inadequately controlled on basal insulin with or without oral agents.

BACKGROUND: Achieving and maintaining glycemic control is important for people with type 2 diabetes (T2D), to reduce disease-related complications and mortality; however, about half of US patients fail to meet glycemic targets. iGlarLixi, a titratable fixed-ratio combination of insulin glargine 100 U/mL (iGlar) and lixisenatide for once-daily administration, was recently approved by the US Food and Drug Administration for use in adults with T2D inadequately controlled on basal insulin (<60 U daily) or lixisenatide. iGlar and lixisenatide have complementary mechanisms of action, primarily targeting fasting plasma glucose and postprandial plasma glucose, respectively. In the US, iGlarLixi is available in a 3:1 ratio of iGlar and lixisenatide, respectively, across the dosage range of 15-60 U of iGlar and 5-20 µg of lixisenatide. METHODS: This study identified phase 3 trials which assessed the efficacy and safety of iGlarLixi. Relevant trials were LixiLan-O, which compared iGlarLixi with iGlar or lixisenatide alone in insulin-naïve patients, and LixiLan-L, which compared iGlarLixi with iGlar alone in insulin-experienced patients. RESULTS: Patients on iGlarLixi experienced greater A1C reduction and were more likely to achieve A1C <7.0% than its comparators. iGlarLixi mitigated the weight gain associated with iGlar without increasing hypoglycemia risk, and resulted in a lower frequency of gastrointestinal adverse events compared with lixisenatide. CONCLUSIONS: iGlarLixi provides a new approach to therapy intensification in patients with T2D. iGlarLixi showed greater A1C efficacy compared with either iGlar or lixisenatide, mitigating iGlar-associated weight gain, without increasing hypoglycemia risk, and reducing the gastrointestinal side-effects seen with lixisenatide.

Ezrin and moesin function together to promote T cell activation.

The highly homologous proteins ezrin, radixin, and moesin link proteins to the actin cytoskeleton. The two family members expressed in T cells, ezrin and moesin, are implicated in promoting T cell activation and polarity. To elucidate the contributions of ezrin and moesin, we conducted a systematic analysis of their function during T cell activation. In response to TCR engagement, ezrin and moesin were phosphorylated in parallel at the regulatory threonine, and both proteins ultimately localized to the distal pole complex (DPC). However, ezrin exhibited unique behaviors, including tyrosine phosphorylation and transient localization to the immunological synapse before movement to the DPC. To ask whether these differences reflect unique requirements for ezrin vs moesin in T cell signaling, we generated mice with conditional deletion of ezrin in mature T cells. Ezrin-/- T cells exhibited normal immunological synapse organization based upon localization of protein kinase C-theta, talin, and phospho-ZAP70. DPC localization of CD43 and RhoGDP dissociation inhibitor, as well as the novel DPC protein Src homology region 2 domain-containing phosphatase-1, was also unaffected. However, recruitment of three novel DPC proteins, ezrin binding protein of 50 kDa, Csk binding protein, and the p85 subunit of PI3K was partially perturbed. Biochemical analysis of ezrin-/- T cells or T cells suppressed for moesin using small interfering RNA showed intact early TCR signaling, but diminished levels of IL-2. The defects in IL-2 production were more pronounced in T cells deficient for both ezrin and moesin. These cells also exhibited diminished phospholipase C-gamma1 phosphorylation and calcium flux. We conclude that despite their unique movement and phosphorylation patterns, ezrin and moesin function together to promote T cell activation.

The c-Abl tyrosine kinase regulates actin remodeling at the immune synapse.

Actin dynamics during T-cell activation are controlled by the coordinate action of multiple actin regulatory proteins, functioning downstream of a complex network of kinases and other signaling molecules. The c-Abl nonreceptor tyrosine kinase regulates actin responses in nonhematopoietic cells, but its function in T cells is poorly understood. Using kinase inhibitors, RNAi, and conditional knockout mice, we investigated the role of c-Abl in controlling the T-cell actin response. We find that c-Abl is required for normal actin polymerization and lamellipodial spreading at the immune synapse, and for downstream events leading to efficient interleukin-2 production. c-Abl also plays a key role in signaling chemokine-induced T-cell migration. c-Abl is required for the appropriate function of 2 proteins known to be important for controlling actin responses to T-cell receptor (TCR) engagement, the actin-stabilizing adapter protein HS1, and the Rac1-dependent actin polymerizing protein WAVE2. c-Abl binds to phospho-HS1 via its SH2 domains and is required for full tyrosine phosphorylation of HS1 during T-cell activation. In addition, c-Abl is required for normal localization of WAVE2 to the immune synapse (IS). These studies identify c-Abl as a key player in the signaling cascade, leading to actin reorganization during T-cell activation.