I’ve been closely following the arena of stem cells for COVID-19 since the pandemic broke including the efforts of Mesoblast.
Mesoblast unlikely to meet primary endpoints in Phase III COVID trial

Now, the firm got bad news as its DSMB reported that they are unlikely to meet the primary endpoint for their Phase III trial of their stem cell product for COVID-19 based on preliminary analyses.
Mesoblast had set the endpoint as a “43% reduction in mortality at 30 days for treatment with remestemcel-L.”
It’s unclear how far off the data were from that 43% mark, but the DSMB added another discouraging note by recommending that the trial stop enrollment at just over 220 COVID-19 patients rather than filling out the originally-planned 300 participants.
Is that because the efficacy data are so discouraging? No safety issues have been reported.
This disappointing COVID trial development followed quickly on the heels of the firm failing to meet the primary endpoint in a trial for chronic heart failure. Notably, secondary endpoints in that trial were more encouraging.
Ricki Lewis recently wrote about yet another area for the firm, pediatric GvHD, a few months back here on The Niche. They are hoping for FDA approval there.
Mesoblast stock, partner Novartis
This newer COVID study development led to Mesoblast stock plunging on the Australian market. It’s also not great for their partner in this effort, Novartis. From PMLiVE:
“This deal, which saw Novartis pay a $25m upfront payment and invest $25m in Mesoblast equity, has an initial focus on the treatment of ARDS, including when associated with COVID-19. The agreement is yet to formally close, being dependent on certain regulatory reviews.”
It is still possible there could be encouraging news on secondary endpoints, but we’ll have to wait a while for that information. The company has been upbeat for months about this approach as you can see in the video below.
Discouraging for general idea of stem cells for COVID-19
I also see this news as a substantial dent to the general notion of stem cells for COVID-19.
While it is true that the many firms and research groups trying out stem cells and other cellular therapies for COVID-19 are using diverse kinds of cellular products, like Mesoblast they almost all seem founded on the central, shared idea of these cells reducing harmful immune responses such as cytokine storms and inflammation.
Admittedly, I’ve been a skeptic of this whole idea from the beginning of the pandemic. My reasons include the fact that there have been little preliminary encouraging preliminary data to back up the flood of new trials in this area and that steroid treatment, which generally operates in a similar way in the body as that hypothesized for stem cells, has rapidly become widely adopted as part of the regimen for very sick COVID patients.
It is clear that the baseline changed for the Mesoblast trial as more treatments were identified for treating patients, eg steroids.
There are other stages of Covid where MSCs may have benefit, such as the ARDS like symptoms experienced by patients after they leave hospital. Clearly there is some pulmonary damage experienced by these patients and MSCs may minimize progression by decreasing inflammation.
It is early days and better designed clinical trials will be possible as we understand the disease more thoroughly.
Stem cells will never be a treatment for Covid19. Mesenchymal stem cells may help to reduce inflammation but a dose of dexamethasone is much cheaper and much more effective. Stem cell hype needs to stop.
maybe just maybe you need Blastomere Embryonic stem cells b/c of immune modularizes being more potent