A new clinical study shows that an inhibitor of Fas ligand (FasL), also called CD95 ligand (CD95L), led to a faster recovery of COVID-19 patients and reduced mortality. On average, it took eight days to recover for patients who received asunercept, a biotherapeutic FasL inhibitor, compared to 13 days in the control group. In addition, mortality was decreased by about 20 per cent.
The study 'Efficacy and safety of asunercept, a CD95L-selective inhibitor, in hospitalised patients with moderate-to-severe COVID-19: ASUNCTIS, a multicentre, randomised, open-label, controlled, phase 2 trial' has been published in eClinicalMedicine . The physiological role of FasL is to keep cells of the immune system, so called T lymphocytes, short T cells , under control by killing them once they have fulfilled their function. In patients with severe COVID-19, however, the immune system is hyper-activated causing an over-production of FasL.
As a result, FasL does two things: it kills way too many T cells and it also attacks normal lung cells. This aberrant increase in cell death causes lymphopenia, that is the loss of lymphocytes, and severe lung inflammation, two hallmark characteristics of severe COVID-19. The new therapeutic concept is based on blocking FasL and to thereby prevent the untoward death of T cells and lung epithelial cells and the inflammation resulting therefrom.
The academic members of the research team that conducted the clinical trial recently demonstrated in a preclinical mode.