Sure, it's a retrospective study, but then the authors aren't...

Sure, it's a retrospective study, but then the authors aren't trying to submit it to the FDA as adequate evidence of efficacy for treatment of children under 12. Which is exactly what Mesoblast has been attempting for the past 3 or 4 years. And the Silviu fan club are fond of saying well what about long term survival as proof of efficacy? In that study two year survival with Ruxolutinib was as good or better than Remestemcel, so Mesoblast's claims of superior survival suddenly evaporate along with the claims by posters here that there are "no alternatives". Mesoblast have attempted to cherry pick controls, just as in the Covid-ARDS trial which came unglued in a randomised controlled clinical trial. That's why the FDA want a randomised controlled trial.