Mission Bio's Tapestri Enables Single-Cell Profiling of Residual Disease, Identifying AML Patients Likely to Benefit from Motixafortide in the Multicenter BLAST Trial

Randomized phase II BLAST trial retrospective analysis utilizing the Tapestri™ single-cell multiomic platform of the randomized multicenter phase II BLAST clinical trial identifies high CXCR4 expression on residual leukemic cells as a candidate predictive biomarker for Motixafortide treatment in acute myeloid leukemia (AML) patients, a signal invisible to the standard of care analysis methods used in the original clinical trial.

SOUTH SAN FRANCISCO, Calif. & HEIDELBERG, Germany--(BUSINESS WIRE)--Mission Bio, a leader in single-cell multiomics, jointly announces with Heidelberg University Hospital, Martin Luther University Halle-Wittenberg, the East German Study Group for Hematology and Oncology (OSHO), and the Study Alliance Leukemia (SAL) findings from a retrospective single-cell analysis of the randomized, double-blind, placebo-controlled phase II BLAST clinical trial in acute myeloid leukemia (AML). The investigator-initiated trial was sponsored by Martin Luther University Halle-Wittenberg, scientifically coordinated and led by Heidelberg University Hospital, and conducted at 29 academic centers in Germany with the active support of OSHO and SAL.

The initial clinical trial tested whether adding the CXCR4 inhibitor Motixafortide to high-dose cytarabine consolidation could reduce the risk of relapse in 128 AML patients in first complete remission. Across the overall cohort, the clinical trial did not meet its primary endpoint, demonstrating a median relapse-free survival (RFS) of 10.3 months with Motixafortide and 11.5 months with placebo (log-rank p = 0.98). A prespecified retrospective analysis of bone marrow samples using single-cell DNA and protein profiling on the Mission Bio Tapestri platform examined whether a clinically defined subgroup might nevertheless benefit.

Among patients treated with Motixafortide, high CXCR4 expression on residual leukemic cells was associated with a significantly reduced risk of relapse (p = 0.047). In the placebo arm, the same marker was associated with significantly elevated relapse risk (p = 0.02), consistent with the established role of the CXCR4-CXCL12 axis in bone-marrow-mediated chemoresistance. A multivariable Cox model confirmed a significant treatment-by-CXCR4 interaction (p = 0.0015).

In the post-consolidation setting, residual leukemic cells are rare and embedded in a largely normal bone marrow background. Standard-of-care analysis methods cannot reliably attribute CXCR4 signal to residual leukemic cells from the normal hematopoietic cells. By linking CXCR4 protein expression to genetically defined leukemic clones at single-cell resolution, the Tapestri platform made it possible to detect this subgroup. In individual patients, genetically distinct subclones showed divergent CXCR4 dynamics over the course of treatment, illustrating the clonal heterogeneity that standard-of-care analysis methods cannot resolve.

The results suggest that CXCR4 expression, when assessed specifically on residual leukemic cells and in the context of their clonal identity, may serve as a predictive biomarker for Motixafortide therapy in AML. The team emphasized that the analysis is retrospective and hypothesis-generating, and that the findings need to be confirmed in a prospective, biomarker-stratified clinical trial before they can guide treatment decisions in routine practice. This study supports integrating functional, clonally resolved single-cell measurable residual disease (MRD) profiling, as enabled by the Tapestri platform, into the design of future AML clinical trials.

"Our analysis suggests that the same biological marker can carry very different meanings depending on the treatment context. Patients with high CXCR4 expression on residual leukemic cells are at particularly high risk of relapse, but they also appear to benefit most from CXCR4 inhibition. Reliably identifying these patients requires measuring CXCR4 directly on residual leukemic cells and linking it to their clonal architecture, which is what single-cell MRD profiling enables," said Enise Ceran, MD, first author of the study, Medical Department V, Heidelberg University Hospital.

"These results demonstrate the need for single-cell MRD approaches to functionally characterize the molecular and phenotypic landscape of residual disease, enabling the identification of biomarker-driven therapy selection to treat AML," said Carsten Müller-Tidow, MD, corresponding author and Professor of Medicine, Hematology, Oncology and Rheumatology at Heidelberg University Hospital.

“AML is not a single disease. It is a dynamic, evolving ecosystem of clones, and this analysis proves that the right drug, matched to the right patient, works. Motixafortide works powerfully in CXCR4-high patients. Tapestri is what makes that match possible," said Zivjena Vucetic, MD, PhD, Chief Medical Officer of Mission Bio.

Mission Bio added that AML's clonal complexity means that population-level assays can obscure the biology driving relapse. The company is actively working with clinical partners to incorporate Tapestri-based biomarker screening into prospective trial protocols.

The findings will be presented as a proffered abstract at the European Hematology Association (EHA) Congress 2026 in Stockholm, June 11–14, 2026. The full results have been published in Blood: Ceran E, Jaramillo S, Merbach AK, et al. Inhibition of high CXCR4 with Motixafortide and absence of single-cell MRD predict outcome after AML consolidation. Blood. 2026. doi:10.1182/blood.2025032033

About Mission Bio

Mission Bio is the single-cell multi-omics leader. The company’s Tapestri Platform is unique in its capabilities, offering an unparalleled level of granularity and precision that is critical for complex research areas such as cancer studies, pharmaceutical development, and advanced cell and gene therapies. Unlike traditional standard of care methods, Tapestri provides a level of precision that opens the door for more tailored and effective treatment strategies, notably by advancing the clinical utility of measurable residual disease (MRD) monitoring in diseases like acute myeloid leukemia (AML). Researchers globally depend on Tapestri to identify rare cell populations, understand mechanisms of therapeutic resistance and response, and establish key quality metrics for next-generation medical treatments. With the Tapestri Platform, Mission Bio continued to set the standard in the field, contributing significantly to the progress of personalized medicine and targeted therapies. To learn more about Mission Bio and the Tapestri Platform, please visit missionbio.com.