Effectiveness of ustekinumab dose escalation in Crohn's disease patients with insufficient response to standard-dose subcutaneous maintenance therapy

Background Ustekinumab is effective in Crohn's disease. However, a substantial proportion of patients will not respond or lose response to ustekinumab. The current evidence to support the effectiveness of dose-optimisation for ustekinumab nonresponse is limited.Aim To assess the effectiveness of dose escalation of ustekinumab.Methods This was a multicentre retrospective cohort study. We included active Crohn's disease patients who received a standard-dose intravenous induction and at least one subcutaneous ustekinumab 90 mg dose. All enrolled patients received dose escalation by either shortening the interval between the doses to every 4 or 6 weeks, intravenous reinduction or a combination of strategies. The primary outcome of the study was clinical response at week 16 after dose escalation.Results A total of 142 patients (22 centres/14 countries) were included. The patients were dose-escalated after a median treatment duration of 30 weeks. At week 16 from escalation, 73/142 (51.4%) responded to treatment, including 55/142 (38.7%) in clinical remission. Corticosteroid-free remission was achieved in 6/34 (17.6%) patients on corticosteroids at the time of escalation; 118/142 (83%) continued treatment beyond week 16. Follow-up data beyond week 16 were available for 74/118 (62.7%) patients. On the last follow-up, 51/98 (52%) patients with available data responded to treatment, including 41/98 (42%) in clinical remission.Conclusions Intensification of ustekinumab maintenance dosage was effective in over 50% of the patients. This strategy should be considered in patients who are nonresponsive to every 8 weeks ustekinumab maintenance dosing

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements