Gilead vs Mesoblast, page-274

It's possible but it sort of needs to work even with co-morbidities... The trial is for ARDS patients <3 days on a ventilator. So the quite ill but not yet absolutely critical. If it's efficacous even for a decent percentage (and not harmful to many / any) it can be approved.

The FDA and Meosblast could always do a Phase 4 study afterwards

Phase 4: Studies occurring after FDA has approved a drug for marketing. These including postmarket requirement and commitment studies that are required of or agreed to by the sponsor. These studies gather additional information about a drug's safety, efficacy, or optimal use.