Table 1 Therapy’s cast of characters.

Cell-based therapeutics are compared to small molecules and biologics.

ComparisonsSmall molecules and BiologicsCells
SelectivityMolecular recognitionComplex sensing and response
DistributionDiffusion and transport
Controlled PK/PD
Directed cell migration
DoseControlled at time of administrationCell decision-making:
• Proliferation/activation/death
• Closed-loop autoregulation
Therapeutic nicheConditions for which distribution and duration of action do not need fine
Conditions that require precise dynamic control over distribution, level, and duration of action