Cell-based therapies for a variety of lung diseases can be considered safe, according to an analysis that pooled data from all available clinical trials of stem cell therapies.
Although death rates were lower in treated patients compared to controls, findings did not indicate any statistically significant differences in either the risk of death or other adverse events among the studies.
The analysis, “Serious adverse events of cell therapy for respiratory diseases: a systematic review and meta-analysis,” was published in the journal Oncotarget.
All trials to date using stem cells for the treatment of lung conditions looked at whether the treatments are safe for patients. But researchers at the University of Texas Health Northeast and Xinxiang Medical University in China argued that the studies were far too small to reach solid conclusions about the safety of cell-based procedures.
To get a better picture, they analyzed data from 23 published studies of cell-based treatments in lung diseases. In addition to one study of sarcoidosis, they included patients with acute respiratory distress syndrome (ARDS), bronchopulmonary dysplasia, pulmonary arterial hypertension, silicosis, extensively drug-resistant tuberculosis, chronic obstructive pulmonary diseases (COPD), and idiopathic pulmonary fibrosis.
The studies varied in design, the type of cell therapy used, and the method of administration of the treatment. The largest patient groups included people with acute lung injury and COPD.
The one study which focused on sarcoidosis included four patients, who were treated with donated mesenchymal stem cells.
Mesenchymal stem cells were the cell type most commonly used. Three studies used autologous endothelial progenitor cells (EPCs) and one used stem cell-containing umbilical cord blood.
The team found that 5.7 percent of all patients who received cell therapy had died, compared to 12.4 percent of untreated controls. Despite this gap, there was no statistically significant difference in risk of death between the groups.
None of the deaths were considered related to treatment, according to the original study investigators.
There was also no statistical difference in other serious adverse events between treated patients and controls, making the researchers conclude that “non-fatal SAEs [serious adverse events] may not be a concern of cell therapy for respiratory diseases.”
When combining deaths and other serious adverse events, there were numerically fewer events in treated patients, but again, no statistical difference between treated and untreated patients.
An analysis of laboratory measures also did not find that cell therapy posed a risk to patients.
“We conclude that either infusion or instillation of mesenchymal stem stromal or progenitor cells are well tolerated without serious adverse events causally related to cell treatment,” the team wrote. “Cell therapy has not been associated with significant changes in spirometry, immune function, cardiovascular activity, and the quality of life.”