Specific and potent caspase inhibitors are indispensable for the dissection of the intricate pathways leading to apoptosis. We selected a designed ankyrin repeat protein (DARPin) from a combinatorial library that inhibits caspase-2 in vitro with a subnanomolar inhibition constant and, in contrast to the peptidic caspase inhibitors, with very high specificity for this particular caspase. The crystal structure of this inhibitor (AR_F8) in complex with caspase-2 reveals the molecular basis for the specificity and, together with kinetic analyses, the allosteric mechanism of inhibition. The structure also shows a conformation of the active site that can be exploited for the design of inhibitory compounds. AR_F8 is a specific inhibitor of an initiator caspase and has the potential to help identify the function of caspase-2 in the complex biological apoptotic signaling network.
Introduction: Mutations in erb-b2 receptor tyrosine kinase 2 (HER2) oncogene are observed in approximately 3% of lung adenocarcinomas or mixed tumors with adenocarcinoma component. Activity of various biologically distinct HER2 inhibitors, including the pan-HER inhibitor afatinib, has been reported in several retrospective trials or small series in advanced pretreated NSCLC with HER2 mutations. We report the first prospective evaluation of afatinib for the treatment of this molecularly defined entity. Methods: NICHE, a single-arm phase II trial using a twostage Simon's design, explored the potential of afatinib to control disease in pretreated patients with advanced NSCLC harboring HER2 exon 20 mutations. A total of 13 patients entered the trial and were treated with afatinib 40 mg/day until tumor progression or lack of tolerability. Results: The first-stage stopping boundary was crossed when five of nine patients did not achieve disease control at 12 weeks. The accrual into the trial was stopped with total 13 patients enrolled, with 7 (53.8%) achieving disease control at 12 weeks. Except for 1 patient with early death, progression was documented for all patients, with median progression-free survival of 15.9 weeks (95% confidence
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