Impact of chromosomal abnormalities on the efficacy of lenalidomide plus dexamethasone treatment in patients with relapsed/refractory multiple myeloma

Targeting UCHL1 Induces Cell Cycle Arrest in High-Risk Multiple Myeloma with t(4;14)

Multiple myeloma (MM) patients considered to be at high cytogenetic risk commonly fail to respond to standard treatment. A thorough understanding of the molecular mechanism of MM development is, therefore, needed. We endeavored to explore the transcriptional signature among different subgroups of newly diagnosed MM using gene chip-based expression microarray. Bone marrow samples of 15 newly diagnosed Thai MM patients were included. The chromosomal translocation t(4;14) was the most frequently identified genetic alteration in the high-risk subgroup. Cluster analysis from expression profiling demonstrated that high-risk MM have a distinctly different expression pattern compared to standard-risk patients. The most significant differentially expressed gene was UCHL1. Functional enrichment analysis by Gene Set Enrichment Analysis, FUNRICH, and Gene Ontology Panther pathway revealed the gene sets involved in cell cycle control to be enriched in the t(4;14) high-risk group. Interestingly, among the well-established downstream targets of UCHL1, only CCND2 was significantly expressed in the t(4;14) high-risk group. Suppression of UCHL1 protein level by LDN-5744 inhibitor could arrest the cell cycle in G1 phase in cell lines. These findings shed light on the molecular mechanism of UCHL1 in t(4;14) high-risk MM and support the evidence that alteration of the UCHL1 pathway may play a role in the pathogenesis of high-risk MM.

Lenalidomide with dexamethasone to multiple myeloma patients relapsing from bortezomib-based induction therapies: A prospective, observational study

Lenalidomide with dexamethasone (Len/Dex) is considered to be an effective and well-tolerated regimen to treat multiple myeloma (MM) patients relapsing after bortezomib induction therapy. With the increase in novel agents targeting refractory and relapsed MM, the identification of clinical or laboratory variables that can predict the appropriate candidates of Len/Dex is essential. To address this question, we prospectively assessed 38 adult MM patients who received bortezomib-based induction therapy and were administered Len/Dex for their first relapse. These 38 patients were stratified into the symptomatic relapse group (n = 10) and biological relapse group (n = 28) according to the disease status when Len/Dex was initiated. The overall response rate in the symptomatic group and biological relapse group was 70.0% (7/10) and 60.7% (17/28), respectively (P = 0.964). These two groups harbored a comparable median Len/Dex treatment duration (139 vs. 225 days; P = 0.876) and progression-free survival 2 (PFS2) (501 vs. 1289 days; P = 0.410). Multivariate analyses failed to show that treating biological relapse (hazard ratio [HR]: 1.29; 95% confidence interval [CI]: 0.43-3.88; P = 0.648), PFS with bortezomib-based induction therapies ≥18 months (HR: 1.79; 95% CI: 0.64-5.01; P = 0.266), autologous hematopoietic stem cell transplantation (HR: 2.18; 95% CI: 0.56-8.55; P = 0.262), and high-risk cytogenetics (HR: 0.85; 95% CI: 0.18-3.93; P = 0.835) were attributed to depth of Len/Dex treatment. In conclusion, whether MM patients treated by Len/Dex for biological relapse would have a better outcome than those prescribed for symptomatic relapse remains inconclusive. Treating significant biological relapse and symptomatic relapse remains the current consensus.

Expression, mutation, and methylation of cereblon-pathway genes at pre- and post-lenalidomide treatment in multiple myeloma

Cereblon (CRBN) is a target for immunomodulatory drugs. This study investigated the prognostic value of the expression of CRBN‐pathway genes on the clinical relevance of lenalidomide (Len) treatment and evaluated the levels of CRBN‐binding proteins and mutations in these genes after Len treatment. Forty‐eight primary multiple myeloma cells were collected prior to treatment with Len and dexamethasone (Ld) and 25 paired samples were obtained post‐Ld therapy. These tumor cells were used to determine the expression and mutated forms of the CRBN‐pathway genes. Following normalization with CRBN levels, there was a significantly reduced IKZF1/CRBN ratio in samples that responded poorly to Ld therapy. Moreover, patients with low ratios of IKZF1/CRBN showed a significantly shorter progression‐free survival (PFS) and overall survival (OS) than those with higher ratios. However, patients with high ratios of KPNA2/CRBN showed a significantly shorter PFS and OS than patients with lower ratios. Of the 25 paired samples analyzed, most samples showed a reduction in the expression of CRBN and an increase in IKZF1 gene expression. No mutations were observed in CRBN, IKZF1, or CUL4A genes in the post‐Ld samples. In conclusion, a decreased expression of IKZF1 and increased expression of KPNA2 compared to that of CRBN mRNA predicts poor outcomes of Ld therapy.