- Combined positive score is a robust, reproducible PD-L1 scoring method that predicts response to pembrolizumab in patients with G/GEJ cancer. This novel scoring method supported US Food and Drug Administration approval of pembrolizumab as third-line therapy for G/GEJ cancer and has facilitated investigation in other indications.

e14589 Background: Developing clinically relevant and highly reproducible scoring methods for PD-L1 to identify patients who will respond effectively to anti-PD-1 therapy is key in the development of companion or complementary diagnostic assays. Methods: Scoring method for PD-L1 IHC 22C3 pharmDx in NSCLC have only captured the percentage on stained tumor cells using the tumor proportion score (TPS) (Roach et al. 2016, Appl Immunohistochem Mol Morphol.) (Garon et al. 2015, N Engl J Med.). In the KN012 study 2 out of 11 responders to pembrolizumab were detected with the TPS for the gastric indication. More and more additional data indicate that in some tumor indications PD-L1 staining on both tumor and tumor-associated immune cells is associated with clinical outcome. Therefore a method evaluating both tumor and immune cells in one sitting using the combined positive score was evaluated. Results: Scoring the same patient specimens with the new combined positive score method resulted in the detection of 9 out of 11 responders. Our internal inter- and intra- observer data shows that the CPS can be scored reproducibly with an overall agreement point estimates of 93% for intra-observer and an overall agreement of 87.6% for inter-observer reproducibility in gastric carcinoma. Additionally, CPS builds on the scoring method for NSCLC as it shares the same denominator, namely total number of tumor cells. CPS is evaluated based on the number of PD-L1 positive cells (tumor, lymphocytes and macrophages) in relation to total tumor cells, and hence allows the capture of tumor and immune cells in a single read. Conclusions: Our data demonstrates that the CPS scoring method is reproducible when scored by pathologists and clinically relevant for a number of indications.

Rats allowed extended daily access (6 h) to cocaine, consume high doses of the drug and escalate their cocaine intake over days, resembling the pattern of cocaine use seen in human addicts. The current study was designed to test whether such animals would also demonstrate the heightened motivation to seek cocaine seen in human addicts. Rats were trained to lever press for i.v. cocaine (0.25 mg/infusion) over a 5-day period of 1 h sessions. Subjects were then assigned to either a brief-access (1 h/day) or an extended-access condition for an additional 10 days. Control rats lever pressed for i.v. saline. Following the final self-administration session animals were tested for their motivation to receive cocaine in an operant runway apparatus. Extended-access animals exhibited significantly higher motivation for cocaine in the runway (where they received 1.0 mg/kg cocaine i.v. upon goal-box entry) as was evident by faster run times and less ambivalence about entering the goal box (i.e. retreat behavior) than either brief-access or control subjects. Brief and extended-access animals, tested in the Elevated Plus Maze, exhibited comparable and significant increases in anxiety following a single 1.0 mg/kg i.v. injection of cocaine, as compared to saline control animals that were challenged with i.v. saline infusion. Together, these data suggest that extended access to cocaine results in an especially high motivation for the drug that is not accounted for by reductions in the anxiogenic properties of cocaine.

Rationale In addition to its rewarding actions, cocaine has profound negative effects that are unmasked as the rewarding impact of the drug fades. While much is known about the neurobiology of cocaine reward, the mechanisms underlying the negative actions of the drug remain unclear. Objectives The current study investigates the role of three brain regions each implicated in the modulation of negative affective states—the bed nucleus of the stria terminalis (BNST), the central (CeA), and the basolateral (BLA) nucleus of the amygdala. Methods The dual actions of cocaine were assessed using a runway self-administration procedure in which rats exhibit both approach to and avoidance of a goal box associated with cocaine administration (retreat behaviors). Here, rats ran a straight alley once/day for i.v. cocaine (1.0 mg/kg/injection) over 14 days during which the BNST, CeA, or BLA was inactivated via bilateral intracranial infusions of lidocaine (0 or 20 μg/0.5 μl/side) administered 15 min prior to testing. The impact of lidocaine on spontaneous locomotor activity was also assessed to rule out nonspecific actions of the treatments. Results Control animals running for cocaine developed the expected pattern of approach–avoidance retreat behavior. Inactivation of the BNST attenuated such behavior, BLA inactivation had no appreciable effects, and CeA inactivation produced intermediate and more variable results. Locomotor activity was unaffected by any of the treatments. Conclusions These data suggest that the BNST and to a lesser extent the CeA, but not the BLA, play a role in mediating the opponent-process actions of self-administered cocaine.