Update on remestemcel-L in ventilator-dependent patients with moderate to severe acute respiratory distress syndrome due to COVID-19 infection .-Mesoblast + Novartis

Mesoblast Limited provided an update on the randomized controlled trial of remestemcel-L in ventilator-dependent patients with moderate to severe acute respiratory distress syndrome (ARDS) due to COVID-19 infection after the Data Safety Monitoring Board (DSMB) performed a third interim analysis on the trial’s first 180 patients . The trial was powered to achieve a primary endpoint of 43% reduction in mortality at 30 days for treatment with remestemcel-L on top of maximal care in a trial of 300 patients. This projected mortality reduction was based on pilot data observed during the initial stages of the pandemic when control mortality rates were exceedingly high and prior to new evolving treatment regimens that have reduced disease mortality in ventilated patients. The DSMB reported that there were no safety concerns and noted that the trial is not likely to meet the 30-day mortality reduction endpoint at the planned 300 patient enrolment. The DSMB recommended that the trial complete with the currently enrolled 223 patients, and that all be followed-up as planned. Notably, the trial has not yet accrued data on the secondary endpoints, which include days alive off mechanical ventilation at 60 days post randomization, overall survival, days in intensive care, duration of hospitalization, and cardiac, neurological, and pulmonary organ damage. Additionally, measures of circulating cytokines and inflammatory markers will be evaluated. None of these were included in the interim analysis. As such, the trial will evaluate all 223 enrolled patients through 60 days of follow-up to study potential treatment effects on these outcomes. Mesoblast and Novartis will both analyse these results to identify meaningful clinical outcomes that may guide decisions on the development program for remestemcel-L in non-COVID ARDS. During the course of the trial, as the pandemic has evolved, numerous changes in the treatment regimens for COVID-19 patients occurred, including both prior to and while on mechanical ventilation that may have an effect on the mortality endpoint in the trial. These include extended management of patients prior to ventilator support, and use of experimental therapies such as dexamethasone, antivirals, and re-purposed immunomodulatory agents. All of these may have changed the natural course of ventilated patients and reduced overall mortality rates during the trial compared to the early stages of the pandemic.