ASSIST CLAD phase II: MSCs for new onset CLAD

Results from the multicenter, double-blind, randomized controlled, phase II ASSIST CLAD trial, evaluating intravenous (IV) allogeneic bone marrow-derived mesenchymal stromal cells (MSCs; n = 27) vs placebo (n = 31) in lung transplant recipients with new-onset chronic lung allograft dysfunction (CLAD), were published in the Journal of Heart and Lung Transplantation by Chambers et al. The primary endpoint was progression-free survival (PFS) at 12 months, defined as a composite of all-cause mortality and freedom from CLAD progression. CLAD progression was defined as a fall in forced expiratory volume in 1 second (FEV₁) >10% from the mean of the screening and baseline FEV₁. 

Key data: PFS at 12 months was 41% in the MSC group vs 55% in the placebo group (relative risk, 0.74; 95% confidence interval [CI], 0.42–1.29; p = 0.30). Lung function decline was similar between groups; the slope coefficient for FEV₁ decline was –6.43 mL/week vs –9.14 mL/week (difference, 2.56 mL/week; p = 0.50) and the median slope coefficient for forced vital capacity (FVC) decline was –4.58 mL/week vs –4.19 mL/week (difference, –0.39; p = 0.85) in the MSC vs placebo groups, respectively. The rate of adverse events (AEs) was similar between groups. The most common AEs in both groups were respiratory tract infections, dyspnea, and fatigue. There were no Grade ≥3 infusion-related AEs.   

Key learning: Intravenous allogeneic MSC therapy did not significantly improve PFS or reduce the rate of lung function decline in lung transplant recipients with new-onset CLAD vs placebo.