Phenotypic and genomic analysis of multiple myeloma minimal residual disease tumor cells: a new model to understand chemoresistance

Persistence of chemoresistant minimal residual disease (MRD) plasma cells (PCs) is associated with inferior survival in multiple myeloma (MM). Thus, characterization of the minor MRD subclone may represent a unique model to understand chemoresistance, but to our knowledge, the phenotypic and genetic features of the MRD subclone have never been investigated. Here, we compared the antigenic profile of MRD vs diagnostic clonal PCs in 40 elderly MM patients enrolled in the GEM2010MAS65 study and showed that the MRD subclone is enriched in cells overexpressing integrins (CD11a/CD11c/CD29/CD49d/CD49e), chemokine receptors (CXCR4), and adhesion molecules (CD44/CD54). Genetic profiling of MRD vs diagnostic PCs was performed in 12 patients; 3 of them showed identical copy number alterations (CNAs), in another 3 cases, MRD clonal PCs displayed all genetic alterations detected at diagnosis plus additional CNAs that emerged at the MRD stage, whereas in the remaining 6 patients, there were CNAs present at diagnosis that were undetectable in MRD clonal PCs, but also a selected number of genetic alterations that became apparent only at the MRD stage. The MRD subclone showed significant downregulation of genes related to protein processing in endoplasmic reticulum, as well as novel deregulated genes such as ALCAM that is prognostically relevant in MM and may identify chemoresistant PCs in vitro. Altogether, our results suggest that therapy-induced clonal selection could be already present at the MRD stage, where chemoresistant PCs show a singular phenotypic signature that may result from the persistence of clones with different genetic and gene expression profiles. This trial was registered at www.clinicaltrials.gov as #NCT01237249

Prognostic value of antigen expression in multiple myeloma: a PETHEMA/GEM study on 1,265 patients enrolled in four consecutive clinical trials

Persistence of minimal residual disease (MRD) after treatment for myeloma predicts inferior outcomes, but within MRD-positive patients there is great heterogeneity with both early and very late relapses. Among different MRD techniques, flow cytometry provides additional information about antigen expression on tumor cells, which could potentially contribute to stratify MRD-positive patients. We investigated the prognostic value of those antigens required to monitor MRD in 1265 newly diagnosed patients enrolled in the GEM2000, GEM2005MENOS65, GEM2005MAS65 and GEM2010MAS65 protocols. Overall, CD19pos, CD27neg, CD38lo, CD45pos, CD81pos, CD117neg and CD138lo expression predicted inferior outcomes. Through principal component analysis, we found that simultaneous CD38lowCD81posCD117neg expression emerged as the most powerful combination with independent prognostic value for progression-free survival (HR:1.69; P=0.002). This unique phenotypic profile retained prognostic value among MRD-positive patients. We then used next-generation flow to determine antigen stability throughout the course of the disease, and found that the expression of antigens required to monitor MRD is mostly stable from diagnosis to MRD stages, except for CD81 whose expression progressively increased from baseline to chemoresistant tumor cells (14 vs 28%). Altogether, we showed that the phenotypic profile of tumor cells provides additional prognostic information, and could be used to further predict risk of relapse among MRD-positive patients

Minimal residual disease monitoring and immune profiling using second generation flow cytometry in elderly multiple myeloma

The value of minimal residual disease (MRD) in multiple myeloma (MM) has been more frequently investigated in transplant-eligible than elderly patients. Since an optimal balance between treatment efficacy and toxicity is of utmost importance in elderly MM, sensitive MRD monitoring might be particularly valuable in this patient population. Here, we used 2nd generation 8-color multiparameter-flow-cytometry (MFC) to monitor MRD in 162 transplant-ineligible MM patients enrolled in the PETHEMA/GEM2010MAS65 study, The transition from 1st to 2nd generation MFC resulted in increased sensitivity, and allowed to identify three patient groups according to MRD levels: MRD-negative (75-years (HR:4.8; P<.001), and those with high-risk cytogenetics (HR:12.6; P=.01). Using 2nd generation MFC, immune profiling concomitant to MRD monitoring also contributed to identify patients with poor, intermediate and favorable outcome (25%, 61% and 100% OS at 3-years; P=.01); the later patients being characterized by an increased compartment of mature B-cells. Our results show that similarly to transplant-candidates, MRD monitoring is one of the most relevant prognostic factors in elderly MM, irrespectively of patients’ age and cytogenetic risk

Nilotinib first-line therapy in patients with Philadelphia chromosome-negative/BCR-ABL-positive chronic myeloid leukemia in chronic phase: ENEST1st sub-analysis

Purpose: The ENEST1st sub-analysis presents data based on Philadelphia chromosome (Ph) status, i.e., Ph+ and Phâ\u88\u92/BCR-ABL1 + chronic myeloid leukemia. Methods: Patients received nilotinib 300 mg twice daily, up to 24 months. Results: At screening, 983 patients were identified as Ph+ and 30 patients as Phâ\u88\u92/BCR-ABL + based on cytogenetic and RT-PCR assessment; 76 patients had unknown karyotype (excluded from this sub-analysis). In the Phâ\u88\u92/BCR-ABL1 + subgroup, no additional chromosomal aberrations were reported. In the Ph+ subgroup, 952 patients had safety and molecular assessments. In the Phâ\u88\u92/BCR-ABL1 + subgroup, 30 patients had safety assessments and 28 were followed up for molecular assessments. At 18 months, the molecular response (MR) 4 rate [MR4; BCR-ABL1 â\u89¤0.01% on International Scale (IS)] was similar in the Phâ\u88\u92/BCR-ABL1+ (39.3%) and Ph+ subgroups (38.1%). By 24 months, the cumulative rates of major molecular response (BCR-ABL1ISâ\u89¤0.1%;), MR4, and MR4.5(BCR-ABL1ISâ\u89¤0.0032%) were 85.7, 60.7, and 50.0%, respectively, in the Phâ\u88\u92/BCR-ABL1 + subgroup, and 80.3, 54.7, and 38.3%, respectively, in the Ph+ subgroup. In both Phâ\u88\u92/BCR-ABL1 + and Ph+ subgroups, rash (20 and 22%), pruritus (16.7 and 16.7%), nasopharyngitis (13.3 and 10.4%), fatigue (10 and 14.2%), headache (10 and 15.8%), and nausea (6.7 vs 11.4%) were frequent non-hematologic adverse events, whereas hypophosphatemia (23.3 and 6.8%), anemia (10 and 6.5%), and thrombocytopenia (3.3 and 10.2%) were the common hematologic/biochemical laboratory events. Conclusion: Based on similar molecular response and safety results in both subgroups, we conclude that Phâ\u88\u92/BCR-ABL1 + patients benefit from nilotinib in the same way as Ph+ patients

Minimal residual disease monitoring and immune profiling using second generation flow cytometry in elderly multiple myeloma

The value of minimal residual disease (MRD) in multiple myeloma (MM) has been more frequently investigated in transplant-eligible than elderly patients. Since an optimal balance between treatment efficacy and toxicity is of utmost importance in elderly MM, sensitive MRD monitoring might be particularly valuable in this patient population. Here, we used 2nd generation 8-color multiparameter-flow-cytometry (MFC) to monitor MRD in 162 transplant-ineligible MM patients enrolled in the PETHEMA/GEM2010MAS65 study, The transition from 1st to 2nd generation MFC resulted in increased sensitivity, and allowed to identify three patient groups according to MRD levels: MRD-negative (75-years (HR:4.8; P<.001), and those with high-risk cytogenetics (HR:12.6; P=.01). Using 2nd generation MFC, immune profiling concomitant to MRD monitoring also contributed to identify patients with poor, intermediate and favorable outcome (25%, 61% and 100% OS at 3-years; P=.01); the later patients being characterized by an increased compartment of mature B-cells. Our results show that similarly to transplant-candidates, MRD monitoring is one of the most relevant prognostic factors in elderly MM, irrespectively of patients’ age and cytogenetic risk