Single Cell RNA Sequencing in Patients Enrolled in a Selinexor Clinical Trial Reveals Overexpression of Alternative Nuclear Export Pathways Associated with Resistance to Selinexor in Refractory Multiple Myeloma (ASH 2021)
We previously reported the discovery of a novel transcriptional signature and therapeutic targets for therapy resistant MM by comprehensive single cell RNA-seq analysis (scRNA-seq) of plasma cells (PCs) in patients with primary refractory MM (PRMM) enrolled in the KYDAR clinical trial (NCT04065789, carfilzomib Lenalidomide dexamethasone daratumumab for PRMM [Cohen YC, Nature Med, 2021]). Here we report scRNA-seq analysis of PCs from patients with advanced refractory MM (aRRMM) (n=21) enrolled in an ancillary sub-study of a prospective clinical trial (XPORT-MM-028, NCT04414475), treated with selinexor combined with dexamethasone (Xd, in penta-refractory MM n=7), or with bortezomib, dexamethasone (XVd, in triple-class refractory [TCR] MM n=9), 5 patients participated in the ancillary study only...Protein-protein interaction enrichment analyses revealed mRNA splicing and capping as well as nucleocytoplasmic transport as up-regulated modules in the refractory patients potentially serving as a resistance mechanism for blockade of XPO1 mediated nuclear export by selinexor. In summary, our study defines a roadmap for combining single cell RNA-seq profiling with clinical trials to stratify patients according to their level of anti-MM drug resistance, to define new biomarkers for drug resistance that may support personalized therapeutic decisions and reveal potential novel targets.