Mesoblast gets FDA RMAT; List of 10 total designations so far

Australian stem cell biotech Mesoblast announced that it has received regenerative medicine advanced therapy (RMAT) designation from the U.S. FDA. This is very good news for the company and an encouraging development for the field.

Interestingly, last month the FDA clarified that there is expanded RMAT designation that can include gene therapies too. At the Meeting on the Mesa in October, an FDA official reportedly presented data indicating that about 1/3 applications for RMATs were granted (see image below from Twitter).

This recently announced RMAT designation is for Mesoblast’s stem cell therapy for heart failure. I’ve posted regularly about Mesoblast over the years and it has been in the stem cell arena for the long haul.

Mesoblast’s RMAT designation is part of a continuing trend whereby the FDA, via the 21st Century Cures Act regenerative medicine provisions, has been rapidly issuing RMAT designations to stem cell biotechs.

Here is a list of the approved RMATs I could find so far:

But I think there are probably more out there. If you know of others not in my list, please let me know. Again, going back to the Meeting on the Mesa, from the FDA slide it seemed like even back then a few months ago there were already 9 approved and possibly 1 pending. Unless a company or other entity announces they got an RMAT, then it seems the FDA isn’t going to be announcing it or providing that info on a database as of yet so it can be hard to find such news.

FDA RMATs
Meeting at the Mesa image on Twitter

Seeking Alpha has more specifics of Mesoblast’s RMAT:

“Mesoblast Limited (NASDAQ:MESOannounces that the FDA has granted Regenerative Medicine Advanced Therapy (RMAT) designation for its mesenchymal precursor cell (MPC) therapy for the treatment of heart failure patients with left ventricular systolic dysfunction and left ventricular assist devices (LVADs).

RMAT status provides for more frequent interactions with the FDA, including discussions of whether Priority Review and/or accelerated approval is appropriate.

A 30-patient pilot trial of Mesoblast’s MPCs at a dose of 25M cells in heart failure patients with LVADs, provided the basis for RMAT designation.

FDA has invited Mesoblast to discuss the development strategy and the evidence needed for approval in an efficient manner.”

For more information from the FDA on RMATs see here and here. In the latter, CBER Director Dr. Peter Marks blogged about RMATs going live.

I see RMATs as a regulatory experiment in the stem cell and regenerative medicine field. So far the RMAT experiment is moving fast, but I haven’t seen reason for clear worry as it is implemented. For instance, I’m not aware of any for-profit stem cell clinic related business having received an RMAT, although at least one self-reported having submitted an application earlier in 2017 that may have been unsuccessful or put on the back burner by the company. Overall, can direct-to-consumer stem cell clinic businesses that have traditionally worked around FDA pre-market approval meet the RMAT hurdle such as for robust data? We’ll see.

Note that one of the quirks of the RMAT system is that they were originally to be called RATs, but I think most would agree that RMAT is a better acronym. The other interesting thing about RMATs is that their availability negates the common excuse by some American stem cell clinics that they give non-FDA approved stem cells to patients because the FDA supposedly doesn’t offer faster options for oversight.

Let’s see how the RMAT experiment goes in 2018. I’d say I’m cautiously optimistic at this early stage.

Note that I’m relying primarily on company’s own announcements of RMAT designation approval from the FDA so in some cases I can’t independently confirm the designation, but have no reason to doubt them.

12 Comments


  1. “Here is a list of the approved RMATs I could find so far”
    Why is Regenexx missing on this list?
    Is Regenexx not approved so far?


    • Regenexx does not have RMAT designation and is not FDA-approved. Personally, I’m a bit leery of their data as well. Take knee data for example. They use means from different cohorts at each post-treatment data point, which is misleading at best. For example, let’s say that 1800 patients at 1-month have responded to surveys. However, at 3 months, there are only 1500 respondents and at 3 years, only 100 (not actual numbers). One cannot compare the mean from those 100 patients at 3 years to the mean of the 1800 patients at one month, which is what they are doing. For a meaningful comparison, one should compare the mean of THOSE 100 PATIENTS at 3 years to THE SAME 100 PATIENTS mean at 1 month. Nobody knows how the other 1700 patients are doing and they should not be included in the comparison. Furthermore, how many patients who did not improve after treatment are going to keep completing surveys for 3 years? Probably not very many. So, the farther this data go out into time, the more likely it is that it will skew positive. They used to include the patient numbers at each data point but have since removed them. I wonder why?

      Before (patient numbers at each data point included) https://web.archive.org/web/20150714070446/http://www.regenexx.com:80/wp-content/uploads/2008/07/RegenexxSD-Infographic-for-Knee-Percentage-Improvement-Fall-2014-v5.pdf

      Now (patient numbers at each data point removed): https://www.regenexx.com/wp-content/uploads/2015/06/knee_infographic_2015.pdf

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