A Novel Dimeric Inhibitor Targeting Beta2GPI in Beta2GPI/Antibody Complexes Implicated in Antiphospholipid Syndrome

Background: b2GPI is a major antigen for autoantibodies associated with antiphospholipid syndrome (APS), an autoimmune disease characterized by thrombosis and recurrent pregnancy loss. Only the dimeric form of b2GPI generated by anti-b2GPI antibodies is pathologically important, in contrast to monomeric b2GPI which is abundant in plasma. Principal Findings: We created a dimeric inhibitor, A1-A1, to selectively target b2GPI in b2GPI/antibody complexes. To make this inhibitor, we isolated the first ligand-binding module from ApoER2 (A1) and connected two A1 modules with a flexible linker. A1-A1 interferes with two pathologically important interactions in APS, the binding of b2GPI/antibody complexes with anionic phospholipids and ApoER2. We compared the efficiency of A1-A1 to monomeric A1 for inhibition of the binding of b2GPI/antibody complexes to anionic phospholipids. We tested the inhibition of b2GPI present in human serum, b2GPI purified from human plasma and the individual domain V of b2GPI. We demonstrated that when b2GPI/antibody complexes are formed, A1-A1 is much more effective than A1 in inhibition of the binding of b2GPI to cardiolipin, regardless of the source of b2GPI. Similarly, A1-A1 strongly inhibits the binding of dimerized domain V of b2GPI to cardiolipin compared to the monomeric A1 inhibitor. In the absence of anti-b2GPI antibodies, both A1-A1 and A1 only weakly inhibit the binding of pathologically inactive monomeric b2GPI to cardiolipin. Conclusions: Our results suggest that the approach of using a dimeric inhibitor to block b2GPI in the pathologica

A phase II single-arm study of irinotecan in combination with temozolomide (TEMIRI) in children with newly diagnosed high grade glioma: a joint ITCC and SIOPE-brain tumour study

A multicenter, two stage phase II study, investigated irinotecan plus temozolomide in children with newly diagnosed high grade glioma. The primary endpoint was tumor response during a two-cycle treatment window, confirmed by external review committee. Patients received oral temozolomide 100 mg/(m 2 day) (days 1-5) and intravenous irinotecan 10 mg/(m2 day) (days 1-5 and 8-12) for two 21-day cycles (three cycles for patients exhibiting objective tumor response). Standard treatment was then administered according to local investigator choice. In total 17 patients were enrolled and treated by local investigators. However, central pathology review found three patients did not have a diagnosis of high grade glioma and another four patients did not have evaluable disease according to independent central radiological review. The primary endpoint was based on the first ten evaluable patients as determined by the external review committee. Recruitment was stopped for futility after there were no complete or partial responses during the two-cycle treatment window in the first ten evaluable patients. Five patients had stable disease, and five progressed. Data for secondary endpoints including; time to tumor progression, time to treatment failure, and overall survival is reported. The safety profile of the treatment showed the combination was tolerable with two patients (11.8 %) having grade three nausea, and one (5.9 %) experiencing a grade four neutropenia, leading to permanent discontinuation from adjuvant treatment. Irinotecan plus temozolomide, although well tolerated did not improve outcome over historical controls in this setting. © 2013 Springer Science+Business Media New York