A randomised, double-blind, placebo-controlled study of the LAG-3-depleting monoclonal antibody GSK2831781 in patients with active ulcerative colitis.

BACKGROUND: Selective depletion of T cells expressing LAG-3, an immune checkpoint receptor that is upregulated on activated T cells, has been investigated in pre-clinical models as a potential therapeutic approach in inflammatory and autoimmune diseases where activated T cells are implicated. AIMS: GSK2831781, a depleting monoclonal antibody that specifically binds LAG-3 proteins, may deplete activated LAG-3+ cells in ulcerative colitis (UC). METHODS: Patients with moderate to severe UC were randomised to GSK2831781 or placebo. Safety, tolerability, efficacy, pharmacokinetics and pharmacodynamics of GSK2831781 were evaluated. RESULTS: One hundred four participants across all dose levels were randomised prior to an interim analysis indicating efficacy futility criteria had been met. Efficacy results focus on the double-blind induction phase of the study (GSK2831781 450 mg intravenously [IV], N = 48; placebo, N = 27). Median change from baseline (95% credible interval [CrI]) in complete Mayo score was similar between groups (GSK2831781 450 mg IV: -1.4 [-2.2, -0.7]; placebo: -1.4 [-2.4, -0.5]). Response rates for endoscopic improvement favoured placebo. Clinical remission rates were similar between groups. In the 450-mg IV group, 14 (29%) participants had an adverse event of UC versus 1 (4%) with placebo. LAG-3+ cells were depleted to 51% of baseline in blood; however, there was no reduction in LAG-3+ cells in the colonic mucosa. Transcriptomic analysis of colon biopsies showed no difference between groups. CONCLUSION: Despite evidence of target cell depletion in blood, GSK2831781 failed to reduce inflammation in the colonic mucosa suggesting no pharmacological effect. The study was terminated early (NCT03893565).

Advancing the match-mismatch framework for large herbivores in the Arctic: Evaluating the evidence for a trophic mismatch in caribou.

Climate-induced shifts in plant phenology may adversely affect animals that cannot or do not shift the timing of their reproductive cycle. The realized effect of potential trophic "mismatches" between a consumer and its food varies with the degree to which species rely on dietary income and stored capital. Large Arctic herbivores rely heavily on maternal capital to reproduce and give birth near the onset of the growing season but are they vulnerable to trophic mismatch? We evaluated the long-term changes in the temperatures and characteristics of the growing seasons (1970-2013), and compared growing conditions and dynamics of forage quality for caribou at peak parturition, peak lactation, and peak forage biomass, and plant senescence between two distinct time periods over 36 years (1977 and 2011-13). Despite advanced thaw dates (7-12 days earlier), increased growing season lengths (15-21 days longer), and consistent parturition dates, we found no decline in forage quality and therefore no evidence within this dataset for a trophic mismatch at peak parturition or peak lactation from 1977 to 2011-13. In Arctic ungulates that use stored capital for reproduction, reproductive demands are largely met by body stores deposited in the previous summer and autumn, which reduces potential adverse effects of any mismatch between food availability and timing of parturition. Climate-induced effects on forages growing in the summer and autumn ranges, however, do correspond with the demands of female caribou and their offspring to gain mass for the next reproductive cycle and winter. Therefore, we suggest the window of time to examine the match-mismatch framework in Arctic ungulates is not at parturition but in late summer-autumn, where the multiplier effects of small changes in forage quality are amplified by forage abundance, peak forage intake, and resultant mass gains in mother-offspring pairs.