This is a developing story.
Potentially controversial results of a Phase 3 stem cell trial were published in the British Medical Journal (BMJ) in October. Initially, it appeared to be a potential breakthrough, building on the foundation of other cardiovascular mesenchymal stem cell trials conducted in recent years. Let’s begin with the study itself, then the criticism.
We know that following a heart attack, your risk of heart failure goes up by quite a lot, anywhere from 10-30% over the next few years. Cardiomyocytes (heart muscle cells) have a poor ability to regenerate, so it’s important to take care of the ones God gave you. Early research has investigated the potential of infusing umbilical-derived mesenchymal stem cells (MSCs) into the heart to mitigate this risk, although the effectiveness remains inconclusive.
Researchers in Iran claimed they took about 400 patients with their first ST-segment elevation myocardial infarction (heart attack) with reduced heart pump function (ejection fraction under 40%), and randomized them in a 1:2 ratio to receive either standard care or intracoronary infusion of MSCs within 3-7 days of a heart attack plus standard care.
They reported very promising results, including:
- The risk of developing heart failure went from about 1 in 6 to 1 in 20 with the infusion (about a 64% relative reduction).
- Of those who developed heart failure, the risk for hospital readmission was about 1 in 9 for standard care and 1 in 40 for the stem cell group (about a 77% relative reduction).
- There were also several other notable findings, including an increased left ventricular ejection fraction and improvements in the composite analysis.
At a glance, this is a rare Phase 3 study using allogeneic birth tissue-derived MSCs, published in the BMJ, a top 4 clinical journal worldwide. Just days later, internet sleuths found inconsistencies in the data, as reported by RetractionWatch.com.
Examples of potential inconsistencies include:
- Study claims it enrolled only patients <65 years old; however, 127 of the patients were older than 65, reports sleuth Dorothy Bishop on Retraction Watch.
- Another sleuth, Nick Brown, reported that the dataset “curiously repeats itself” every 101 records, showing identical values over and over.
It appears the paper’s lead author, Dr. Armin Attar, has replied to comments on PubPeer.com (a community peer-review website), stating, “During an internal audit, we have noticed some inconsistencies in the baseline demographic data of the study. Our team is currently conducting a detailed review to identify the source of these discrepancies. This process is expected to take approximately two to three weeks.”
On November 12, 2025, the BMJ issued an expression of concern, stating “The editors judge that the trial may have breached accepted practices and that the results may not be reliable.” The authors have prepared a replacement dataset, and the BMJ seems to be currently investigating. I imagine we’ll know in the next couple of weeks. Oof.
