Purpose: Approximately one-third of patients with non-small cell lung cancer (NSCLC) harboring tumors with EGFR-tyrosine kinase inhibitor (TKI)-sensitizing mutations (EGFRm) experience disease progression during treatment due to brain metastases. Despite anecdotal reports of EGFR-TKIs providing benefit in some patients with EGFRm NSCLC brain metastases, there is a clinical need for novel EGFR-TKIs with improved efficacy against brain lesions.Experimental Design: We performed preclinical assessments of brain penetration and activity of osimertinib (AZD9291), an oral, potent, irreversible EGFR-TKI selective for EGFRm and T790M resistance mutations, and other EGFR-TKIs in various animal models of EGFR-mutant NSCLC brain metastases. We also present case reports of previously treated patients with EGFRm-advanced NSCLC and brain metastases who received osimertinib in the phase I/II AURA study (NCT01802632).Results: Osimertinib demonstrated greater penetration of the mouse blood-brain barrier than gefitinib, rociletinib (CO-1686), or afatinib, and at clinically relevant doses induced sustained tumor regression in an EGFRm PC9 mouse brain metastases model; rociletinib did not achieve tumor regression. Under positron emission tomography micro-dosing conditions, [11 C]osimertinib showed markedly greater exposure in the cynomolgus monkey brain than [11 C]rociletinib and [ 11 C]gefitinib. Early clinical evidence of osimertinib activity in previously treated patients with EGFRm-advanced NSCLC and brain metastases is also reported.Conclusions: Osimertinib may represent a clinically significant treatment option for patients with EGFRm NSCLC and brain metastases. Further investigation of osimertinib in this patient population is ongoing.

Several neurochemical in vitro and in vivo imaging studies have been aimed at characterizing the localization of serotonin receptors and transporters in the human brain. In this study, a detailed comparison of the distribution of a number of 5-HT receptor subtypes and the 5-HT transporter was carried out in vitro using human postmortem brain tissue. Anatomically adjacent whole hemisphere sections were incubated with specific radioligands for the 5-HT(1A), 5-HT(1B), 5-HT(2A), 5-HT(4) receptors and the 5-HT transporter. The autoradiograms revealed different laminar and regional distribution patterns in the isocortex, where 5-HT(1A) and 5-HT(4) receptor binding showed highest densities in superficial layers and 5-HT(2A) receptor binding was most abundant in middle layers. In cortical regions, 5-HT transporters were concentrated to several limbic lobe structures (posterior uncus, entorhinal, cingulate, insular and temporal polar regions). 5-HT(1A) receptor densities were also high in limbic cortical regions (hippocampus, posterior entorhinal cortex, and subcallosal area) compared to the isocortex. Subregionally different distribution patterns were observed in the basal ganglia with a trend toward higher levels in ventral striatal (5-HT(1B) receptors) and pallidal (5-HT transporters and 5-HT(1B) receptors) regions. The localization in regions belonging to limbic cortico-striato-pallido-thalamic circuits is in line with the documented role of 5-HT in modulation of mood and emotion, and the suggested involvement of this system in pathophysiology of various psychiatric disorders. The qualitative and quantitative information reported in this study might provide important complements to in vivo neuroimaging studies of the 5-HT system.

Preclinical data highlight AZD1390 as a potentially powerful new therapy to enhance brain tumor patient responses to radiotherapy.

Pioneered with the invention of 11 C-Pittsburgh compound B, amyloid-b imaging using PET has facilitated research in Alzheimer disease (AD). This imaging approach has promise for diagnostic purposes and evaluation of disease-modifying therapies. Broad clinical use requires an 18 F-labeled amyloid-b radioligand with high specific and low nonspecific binding. The aim of the present PET study was to examine the radioligand 18 F-AZD4694 in human subjects. Methods: Six control subjects and 10 clinically diagnosed AD patients underwent PET examination with 18 F-AZD4694 and a structural MRI scan. Of these, 4 controls and 4 patients underwent a second PET examination for test-retest analysis. Arterial sampling was done to derive a metabolite-corrected plasma input function for traditional compartment modeling. Besides, several simplified quantitative approaches were applied, including the reference Logan approach and simple ratio methods. Results: After intravenous injection of 18 F-AZD4694, radioactivity appeared rapidly in brain. In patients, radioactivity was high in regions expected to contain amyloid-b, whereas in controls, radioactivity was low and homogenously distributed. Binding in cerebellum, a reference region, was low and similar between the groups. Specific binding was reversible and peaked at about 27 min after injection in regions with high radioactivity. The time-activity curves could be described using the 2-tissuecompartment model. Distribution volume ratio estimates obtained using compartment models and simplified methods were highly correlated. Standardized uptake value ratios calculated at late times and distribution volume ratios estimated with the reference Logan approach were, in gray matter, significantly lower in control subjects (1. Al zheimer disease (AD) was identified more than a century ago on the basis of histopathologic observations. The diagnosis of AD, however, is a clinical challenge, and a definite diagnosis can still only be made after death. In clinical research on AD, the search for sensitive and specific in vivo biomarkers has thus been given high priority. A promising recent approach is the use of PET and radiolabeled ligands targeting amyloid-b deposits in the brain. The first and so-far most successful radioligand is 11 C-labeled 2-[49-(methylamino) phenyl]-6-hydroxybenzothiazole ( 11 C-PIB), which binds predominantly to amyloid-b plaques in the human brain (1). Initial studies have shown that control subjects (CSs) and AD patients can be separated on the basis of their amyloid-b load (2). Subsequently, in vivo amyloid-b imaging has been applied in research on early AD diagnosis (3), evaluation of longitudinal progression of disease (4), and evaluation of new disease-modifying therapies (5).This first generation of amyloid-b radioligands has thereby opened a new field of neuroimaging research. Radioligands such as 11 C-PIB have affinity for amyloid-b in the low-nanomolar range, and a favorable near-stable signal-to-background ratio is obtained during the later phase of data acq...