Partial reprogramming

Partial reprogramming uses transient or low-dose expression of Yamanaka factors to rejuvenate cells without erasing their differentiated identity or inducing pluripotency. Studies in mice show restoration of youthful epigenetic patterns, improved tissue regeneration, and extended healthspan. Because full reprogramming risks teratoma formation, partial protocols aim to capture rejuvenation benefits while preserving cell function. It is an active and contested frontier in longevity research, with safety and durability still under investigation. In January 2026, Life Biosciences' ER-100 — a gene therapy expressing three Yamanaka factors (Oct4, Sox2, Klf4; c-Myc omitted), administered by intravitreal injection — became the first cellular-rejuvenation therapy using epigenetic reprogramming to receive FDA IND clearance; a Phase 1 first-in-human trial (NCT07290244) is enrolling patients with non-arteritic anterior ischemic optic neuropathy (NAION) and open-angle glaucoma.