China-based IASO Biotechnology reported a 90% objective response rate (ORR) and 90% minimal residual disease (MRD) negativity rate in 10 patients with relapsed/refractory multiple myeloma (R/R MM) treated with IASO206, its BCMA-targeted in vivo CAR-T cell therapy. Both rates reached 100% in the high-dose cohort. The first-in-human Phase I data were presented at the 2026 International Myeloma Society Annual Meeting.
Why it matters: In vivo CAR-T has only recently entered human testing, with clinical data so far limited to a handful of small Phase I programs. IASO206 adds one of the larger early efficacy datasets to date and provides further evidence that therapeutically active CAR-T cells can be generated directly in patients without individualized manufacturing or lymphodepleting chemotherapy.
As of the September 26, 2026 data cut-off, 10 patients had received IASO206 across three dose levels. Patients had received a median of three prior lines of therapy, 70% were triple-class exposed, 90% had high-risk cytogenetic abnormalities, and 70% had ultra-high-risk features.
Among the 10 efficacy-evaluable patients, nine responded, including three stringent complete responses, while nine achieved MRD negativity. One patient in the low-dose cohort who remained MRD-positive achieved a very good partial response. Follow-up remains limited, and IASO Bio said responses in several patients were continuing to deepen.
No dose-limiting toxicities, immune effector cell-associated neurotoxicity syndrome (ICANS), or treatment-related deaths were reported. Cytokine release syndrome (CRS) was Grade 1 in seven patients and Grade 2 in one, while two patients experienced no CRS. Two patients developed Grade ≥3 viral infections associated with hypogammaglobulinemia and recovered following intravenous immunoglobulin treatment.