January 17, 2021

The Niche

Trusted stem cell blog & resources

A new paper today in Stem Cells Translational Medicine on a small COVID-19 Phase 1/2a trial using an umbilical cord stem cell product reports a surprising degree of possible efficacy. What’s the scoop here and could there be some hype in the media about this new study such as one of the authors describing the cells as “smart bomb technology in the lung”?

Study of umbilical cord stem cell infusions for COVID-19

umbilical-cord-blood, umbilical cord blood stem cells
A unit of umbilical cord blood. Umbilical cord blood stem cell products could have a number of useful properties. Some researchers, including the authors of the study that is the focus of today’s post, harvest stem/stromal stem cells from the cord itself.

The paper comes from the University of Miami and a team led by Camillo Ricordi.

Even as a skeptic of this approach, I’d say that these are somewhat encouraging results and it’s admittedly not what I expected. It seems almost too good to be true to me, but let’s take a step-by-step approach to thinking it through.

See some important caveats toward the bottom of this post that suggest some caution is needed and we shouldn’t overinterpret the results.

But first, here are the key take-homes from the study and paper:

  • This was a double-blind, placebo-controlled phase 1/2a with a primary objective to study safety, but also looking toward potential efficacy.
  • 12 control and 12 treatment group participants.
  • Two infusions of 100 million umbilical cord mesenchymal stem /stromal cells were delivered within three days so a total of 200 million cells. Control subjects just got placebo (vehicle).
  • The cells did not seem to be associated with adverse events.
  • Patient survival at one month was 91% in the stem cell treated group versus 42% in the control group.
  • Faster recovery: More than 80% of the treatment group recovered by day 30, while less than 37% of the control group recovered by then.
  • As to possible mechanism, some cytokines had better profiles in the treatment group versus controls, while other cytokines were not significantly changed.
  • Further study would be needed to determine if what this study suggests is a real effect or somehow due to the study design or small group of participants, but the study unto itself is encouraging.
  • Dozens of other trials are ongoing in this area.

Caveats to the study

A major caveat to the new Ricardi group paper is it is a very small (24 participants total) trial not powered to clearly measure efficacy.

knot in the umbilical cord
Human umbilical cord. Creative Commons image. Photographer Scott Granneman reported that despite the knot, mother and baby were fine.

There are also a few issues with the trial structure itself such as the reported changing of inclusion criteria midstream, the somewhat lower 02 in the control group to begin with, and a major difference in obesity prevalence in the groups, although it was the treatment group (that fared better) that was more obese.

Based on various reports, one might suppose a group with more obesity might have worse COVID-19. However, we can’t just assume that’s true within a group of 24 people and it’s hypothetically possible that somehow obesity was protective in this instance.

We’ll have to see how other trials turn out.

As an update, a reader has pointed out several more things to consider for this study. The treatment group had quite a few more female participants (who tend to fair better with COVID) and other than obesity, this group was healthier to start with as compared to controls related to hypertension, heart disease, diabetes, and cancer (all of which were higher in the control group, and can be associated with worst COVID outcomes.)

Danger of hype here, looking ahead for cells for COVID-19

Dr.-Camillo-Ricordi
Dr. Camillo Ricordi, senior author of the new study.

The recent bad news for Mesoblast on its MSC trial for COVID-19 had cast some gloom over this area, but what should we think about this new cord blood stem cell report and should it spark more optimism?

It’s hard to say until we see more data and from bigger trials so caution would be wise.

Ricordi was quoted in one media report on their new research in a way that seems way over the top to me (emphasis mine):

“It seemed to me that these stem cells could be an ideal treatment option for severe COVID-19,” said Dr. Ricordi, Stacy Joy Goodman Professor of Surgery, Distinguished Professor of Medicine, and professor of biomedical engineering, microbiology and immunology. “It requires only an intravenous (IV) infusion, like a blood transfusion. It’s like smart bomb technology in the lung to restore normal immune response and reverse life-threatening complications.”

Smart bomb tech?

One of the challenges we sometimes see in the stem cell field is the tendency to want to endow certain stem cells with almost superhero-like powers that can be applied to many diverse diseases. To me at least, that doesn’t always add up.

Overall this new small study is the most encouraging results we’ve seen on the cellular medicine for COVID-19 front, but there are good reasons for wanting a lot more data before coming to any conclusions.

A next step for the team is to see if the umbilical cord cell product can stop disease progression in COVID-19 patients.

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