Shanghai – September 25, 2026 -- A retrospective analysis of 102 multiple myeloma patients treated with IASO Bio's FUCASO CAR-T therapy found that patients maintaining sustained minimal residual disease (MRD) negativity showed a median CAR-T cell persistence of 463 days, compared with 272 days in patients who experienced MRD conversion — a gap of roughly 191 days. The data, drawn from the pivotal FUMANBA-1 registration study, were presented as a poster (Abstract No. PA-469) at the 2026 International Myeloma Society Annual Meeting.
Durable CAR-T persistence tracks with delayed disease progression
The analysis divided 102 MRD-negative patients into a sustained MRD-negative group (n=61) and an MRD-conversion group (n=41), tracking peripheral blood vector copy number (VCN) as a marker of CAR-T cell survival. Time to progression correlated strongly with duration of MRD negativity (tau-b=0.736, P0.0001) and moderately with VCN persistence (tau-b=0.306, P0.0001), while VCN persistence itself correlated with MRD-negative duration (tau-b=0.185, P=0.006). The VCN persistence gap between groups did not reach statistical significance (HR 0.73, 95% CI 0.42–1.26, P=0.2568), a limitation the company attributed to sample size.
High-risk cytogenetics and tumor burden predict early CAR-T clearance
Patients who later experienced MRD conversion carried higher-risk baseline features: 26.8% had del(17p) versus 13.1% in the sustained-negative group, and 26.8% had bone marrow plasma cells at 50% or higher versus 11.5%. The conversion group also had a shorter median interval from diagnosis to enrollment (31.1 months versus 54.0 months) and a higher rate of bridging therapy use (61.0% versus 41.0%), indicating more aggressive, treatment-refractory disease at baseline.
Findings point toward earlier-line CAR-T use and persistence-extension strategies
IASO Bio positioned peripheral blood VCN persistence as a candidate pharmacodynamic marker for durable disease control following CAR-T infusion. Professor Lugui Qiu of the Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences, said the hypothesis-generating results point toward research on extending CAR-T cell persistence and support clinical exploration of using the therapy earlier in the treatment course, particularly for patients with high-risk cytogenetics and high tumor burden who face elevated risk of early cell clearance.