Chapter 1

One of the most important ideas in longevity medicine is that stem cells may matter less because they “turn into” new tissue and more because they send instructions. Those instructions are called a secretome: the mix of proteins, growth factors, cytokines, enzymes, and extracellular vesicles that cells release to tell other cells what to do. In younger biology, those signals tend to support repair, balance, and resilience. With aging, that signaling gets noisier, weaker, and often more inflammatory.

That is why both ThroneBio and Immunis are interesting, even though they are aimed at different problems. ThroneBio’s Stem Cell Educator approach is aimed primarily at immune recalibration: not simply adding cells, but exposing the body’s immune system to signals intended to retrain it. Immunis’s IMM01-STEM, by contrast, is described in the April 2026 executive summary as a stem cell-derived secretome product designed to support muscle and metabolic function. Their thesis is that age-related muscle decline and the lean-mass loss seen with GLP-1 weight-loss drugs are partly a signaling problem. Instead of trying to replace tissue directly, they are trying to restore regenerative signals that have faded with age.

The Immunis data are still early and investigational, but the story is notable. In exploratory Phase 2a work, the company reports clinically meaningful gait-speed improvement in older adults with sarcopenic obesity, improvement in walking distance in elderly knee osteoarthritis patients without a structured exercise program, and preclinical combination data suggesting greater fat loss with lean-mass preservation versus GLP1/GIP alone. No FDA-approved product exists yet, and the company says that plainly. Still, the broader longevity idea is compelling: aging may be, in part, a breakdown in cellular communication. If that is true, secretomes matter because they may help restore thebody’s repair instructions — first in immunity, then in muscle, metabolism, and function.