LONDON — In a watershed moment for post-viral medical research, the highly anticipated STIMULATE-ICP project, the UK government’s flagship initiative to understand and treat long COVID, has concluded that its centerpiece triple-treatment trial failed to produce clinically significant results.

Published and widely discussed in late July 2026, the large-scale trial assessed the effectiveness of three repurposed drug regimens: an anticoagulant (rivaroxaban), an anti-inflammatory (colchicine), and a dual mast-cell inhibitor combination (famotidine plus loratadine) www.healthrising.org . The drugs were selected for their low cost, wide availability, and potential for rapid integration into the National Health Service (NHS) if proven effective.

The trial enrolled approximately 200 participants per treatment arm, comparing the drug regimens against standard specialist supportive care. However, none of the interventions met the threshold for "clinically significant" improvement, which required a minimum 3-point gain on the Fatigue Assessment Scale (FAS). The closest results were seen in the colchicine and famotidine-loratadine groups, which achieved marginal gains of 1.49 and 1.48, respectively www.healthrising.org .

Notably, the anticoagulant rivaroxaban produced minimally negative effects on fatigue scores (-1.06), raising further questions about its utility in this specific patient cohort without clear evidence of thrombotic complications www.healthrising.org .

Despite the disappointing outcomes, medical experts emphasize that the trial provides valuable negative data, steering the clinical community away from ineffective, broad-spectrum repurposing of these specific medications for the general long-COVID population.

Moving forward, researchers are calling for more meticulous, phenotype-driven trials that utilize robust placebo controls and comprehensive, multi-dimensional symptom tracking to unlock effective treatments for post-viral conditions.