Rallybio is a clinical-stage biotech focused on rare and severe diseases, though its trajectory has shifted materially following a pending merger with Candid, a T-cell engager therapeutics company focused on autoimmune diseases. Rallybio's lead asset is RLYB116, a C5 complement inhibitor licensed from Sobi in 2019, targeting conditions where the complement system misfires and attacks the body's own cells. Rallybio is developing RLYB116 for platelet transfusion refractoriness and antiphospholipid syndrome. RLYB116 has completed Phase 1 trials in healthy volunteers and has not yet entered Phase 2. Rallybio argues RLYB116 could be best-in-class versus approved C5 inhibitors like Soliris and Ultomiris, due to its subcutaneous once-weekly autoinjector format, smaller molecule structure, and lower-cost manufacturing via E. coli expression. Rallybio's second asset, RLYB332, is a preclinical matriptase-2 inhibitor targeting iron overload diseases like beta thalassemia, licensed from Kymab in 2022. Rallybio has no approved products and no commercial revenue, funding operations through equity raises and asset deals. Under the pending Candid merger, Rallybio's legacy pipeline assets — including RLYB116 and RLYB332 — will be separated into contingent value rights for existing shareholders, while the combined entity pursues Candid's autoimmune platform, backed by roughly $505M in new financing.