Stem cells for the flu? Pondering PR email, frailty data from Longeveron

Tompkins Figure 2A
Tompkins Figure 2A

Stem cells for flu?

For me, that idea is new.Longeveron Logo

Some months back there was buzz about the stem cell biotech Longeveron related to its report on early trial data on testing infusions of mesenchymal stem cells for frailty in the aged. Frailty that pops up in some aging folks can manifest in a variety of ways and contribute both to reduced quality of life and mortality.

This week a PR firm for Longeveron sent out an email suggesting that the company’s investigational stem cell therapy might have significance for the flu.

My initial reaction was to be puzzled when someone shared the email with me, not just about the idea, but also the timing. Is this kind of taking advantage of the current worrisome news on the flu? Or a logical attempt to tie in ongoing (albeit very early) clinical research to relevant news of the day? More broadly, what should researchers and biotechs keep in mind in talking about their very early translational and clinical work?

I want to emphasize that Longeveron is doing many things right. They have INDs from the FDA and NIH funding for some work. They are conducting small, placebo controlled trials including a double-blind one. They are publishing their data. Kudos to them.

But this stem cells for flu PR email didn’t sit that well with me. Of course, the flu is on everyone’s mind as it is currently an epidemic in the U.S. with many deaths. Is there a reasonable expectation that Longeveron’s product could help older people not get the flu soon or avoid getting as sick via enhancing response to flu vaccine (and/or reducing frailty)? Is this kind of PR email OK at this stage?

Let’s go through the situation.

First, take a look at that email someone passed along to me from the company’s PR firm:

Subject line “Flu season is bad. Could stem cells make the difference for seniors?”
“…this year’s flu season is predicted to be one of the worst in history, according to medical experts, and one of the hardest hit groups is the elderly. Due to their susceptibility to pneumonia and poor lung function, the older population has a higher mortality rate during influenza outbreaks. So far for the 2017/2018 flu season, the National Center for Health Statistics has received reports of 759 deaths due to influenza and 34,520 related deaths due to pneumonia. Experts are looking to other ways to protect the elderly during severe flu outbreaks.
One therapy under investigation is regenerative stem cell therapy to bolster seniors’ immune systems. The research uses stem cells from adult human donor bone marrow to improve the symptoms associated with aging frailty. Frailty is a syndrome that is marked by a number of symptoms, including poorer lung function and physical performance, higher levels of inflammation and a lower immune system. With frailty, the decrease in immune system defense and lowered lung function, along with less efficacy of vaccines, increases the potential for illness such as the flu to be fatal.
Joshua Hare, M.D., co-founder and Chief Science Officer of biotech company Longeveron, and director of the Interdisciplinary Stem Cell Institute at the University of Miami Miller School of Medicine, has been leading the research, and is available for an interview to discuss the research and the promising results.  Longeveron and UM have published positive clinical studies of stem cell therapies for aging frailty, for which there is no FDA-approved treatment.
According to Dr. Hare, after the treatment, frail elderly in the trial demonstrated better physical performance and improved lung function, walking an additional 70 meters, for a total of some 400 meters – about the length of a football field.”

The tone is measured so that’s good on that level, but I still have some concerns here.I asked myself, “What’s the data behind this email from the company?” Their research so far is mostly focused on frailty in terms of data and not the flu.

Even on frailty it’s early days. Longeveron’s recent paper entitled “Allogeneic Mesenchymal Stem Cells Ameliorate Aging Frailty: A Phase II Randomized, Double-Blind, Placebo-Controlled Clinical Trial” got some people’s attention. To my eye the data were not that consistent, error bars large, the sample size small, and we need to keep in mind that in this study the higher dose of stem cells didn’t have much effect or none at all (or possibly made things worse) for certain measures associated with aging. There may be reasons for that dosage difference in outcomes but it weakens the case that the stem cells here definitely helped frailty-associated outcomes. For an example of the kind of data from the paper, see Figure 2A here, which relates to lung function.

This kind of mixed bag of data is not unusual for many kinds of early clinical trials and there could be something meaningful going on. This low-high dose split result reminds me of the mixed bag data reported a few months ago from Duke’s cord blood for cerebral palsy trial (see my post).

Tompkins Figure 2A
Tompkins Figure 2A
With these things in mind and noting that the company just started their small study related specifically to stem cells and flu in 2016, in my opinion it is risky to imply in the public domain that there may be any benefit of a still experimental stem cell transplant for the elderly specifically related to flu. Patients may get the wrong idea. Even the addition of one more sentence noting it’s too early to say if there’s going to be any benefit for flu could have helped give the email more balance.
Overall, for the reasons discussed above I am not a big fan of this kind of PR email in the stem cell arena. I’m sure some biotechs would counter that they need enthusiasm and public interest to move forward, but statements to the public and the press on early trials need to be issued with a lot of care…especially during an epidemic.


  1. The first thing that I think of when I read this about using stem cells to boost the immune system in the elderly is “cytokine storm.”

    I think we need to tread very carefully here because I don’t think we understand the immune system well enough to contemplate this procedure, which, at this point, I would consider to be a stunt.

    I hope that this idea goes nowhere fast.

  2. Paul, the flu angle is a bit of an attention grabber but stem cells will likely have a roll in complications from the flu. One specific example I am thinking of is ARDS. Take a few minutes to read this compassionate use study of two patients with refractory ARDS, one was from complication related to the flu. On their death beds because standard care didn’t work, both miraculously saved by allogeneic MSCs.

  3. Thomas- I know that CAR/T therapies can elicit cytokine storms…but I know of no study in which bone marrow MSCs have been shown to inhibit them. Do you have a reference? I’ve read a bit about allogeneic MSCs, and the general observation is that they express low levels of MHCI and MHCII and are rapidly cleared from the body. There are also reports about allogeneic MSCs inducing a rejection response when injected into the bloodstream. As you know, MSCs are highly variable, and differ depending on their source.

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