Quality Control Standards and Release Criteria for Clinical-Grade Stem Cell Products

Abstract

Background: A cell therapy is released to a patient on a panel of tests, and the panel is largely inherited from criteria written
to make research comparable rather than to predict clinical effect.
Objective: To review the release criteria in current use, what each establishes, and where the evidence for them is weakest.
Methods: Narrative review of position statements, validation studies and published release panels from clinical programmes.
Findings: Across six named clinical programmes, viability specifications sit at 70% or above while identity thresholds for the
same marker range from 30% to 90%. Cells can meet a viability specification and still have lost immunosuppressive function
on thaw. Automated sterility detection flagged all contrived positives within 72 hours against a 14-day compendial incubation,
for products whose shelf life is hours.
Conclusions: Identity and viability are cheap and weakly informative. Potency remains the unsolved problem.