PRESS RELEASE

JANUARY 8, 2026

Osel Enters Agreement with SWOG Cancer Research Network
for First-Ever Pivotal Trial of a Microbiome-Based Therapy in Oncology

Pivotal Phase 3 trial of MO-03 builds on prior studies that demonstrated enhanced immunotherapy benefit without added toxicity

MOUNTAIN VIEW, CA – January 8, 2026 – Osel Inc., a clinical-stage biopharma company pioneering live biotherapeutic products (LBPs), today announced a clinical trial agreement with SWOG Cancer Research Network for a pivotal Phase 3 clinical trial of its lead oncology candidate, MO-03, in combination with standard immuno-oncology (IO) regimens for advanced and metastatic renal cell carcinoma (mRCC). This marks the first-ever pivotal trial of a microbiome-based oral therapy in oncology.

Osel filed a new IND for CBM588 oncology indications in early 2024 and has begun a Phase 1 dose escalation trial in advanced kidney cancer with a new capsule formulation of CBM588 at the City of Hope Comprehensive Cancer Center. The study is now enrolling patients. See clinicaltrials.gov NCT06399419 for contact information.

Osel is pioneering a new class of medicines, Live Biotherapeutic Products
to restore health by modulating the body’s microbiome