Faculty Bibliography

Predicting patient outcome in multiple myeloma remains challenging despite the availability of standard prognostic biomarkers. We investigated outcome for patients relapsing early from intensive therapy on NCRI Myeloma XI. Relapse within 12 months of autologous stem cell transplant was associated with markedly worse median progression-free survival 2 (PFS2) of 18 months and overall survival (OS) of 26 months, compared to median PFS2 of 85 months and OS of 91 months for later relapsing patients despite equal access to and use of subsequent therapies, highlighting the urgent need for improved outcome prediction and early intervention strategies for myeloma patients.

ABSTRACT:The summation of 20 years of biological studies and the comprehensive analysis of more than 1000 multiple myeloma genomes with data linked to clinical outcome has enabled an increased understanding of the pathogenesis of multiple myeloma in the context of normal plasma cell biology. This novel data have facilitated the identification of prognostic markers and targets suitable for therapeutic manipulation. The challenge moving forward is to translate this genetic and biological information into the clinic to improve patient care. This review discusses the key data required to achieve this and provides a framework within which to explore the use of response-adapted, biologically targeted, molecularly targeted, and risk-stratified therapeutic approaches to improve the management of patients with multiple myeloma.

Cell surface expression levels of GPRC5D, an orphan G protein-coupled receptor, are significantly higher on multiple myeloma (MM) cells, compared with normal plasma cells or other immune cells, which renders it a promising target for immunotherapeutic strategies. The novel GPRC5D-targeting T-cell redirecting bispecific antibody, talquetamab, effectively kills GPRC5D+ MM cell lines in the presence of T cells from both healthy donors or heavily pretreated MM patients. In addition, talquetamab has potent anti-MM activity in bone marrow (BM) samples from 45 patients, including those with high-risk cytogenetic aberrations. There was no difference in talquetamab-mediated killing of MM cells from newly diagnosed, daratumumab-naïve relapsed/refractory (median of 3 prior therapies), and daratumumab-refractory (median of 6 prior therapies) MM patients. Tumor cell lysis was accompanied by T-cell activation and degranulation, as well as production of pro-inflammatory cytokines. High levels of GPRC5D and high effector:target ratio were associated with improved talquetamab-mediated lysis of MM cells, whereas an increased proportion of T cells expressing PD-1 or HLA-DR, and elevated regulatory T-cell (Treg) counts were associated with suboptimal killing. In cell line experiments, addition of Tregs to effector cells decreased MM cell lysis. Direct contact with bone marrow stromal cells also impaired the efficacy of talquetamab. Combination therapy with daratumumab or pomalidomide enhanced talquetamab-mediated lysis of primary MM cells in an additive fashion. In conclusion, we show that the GPRC5D-targeting T-cell redirecting bispecific antibody talquetamab is a promising novel antimyeloma agent. These results provide the preclinical rationale for ongoing studies with talquetamab in relapsed/refractory MM.

Enhancer DNA methylation and expression of MYBPHL was studied in multiple myeloma (MM). By bisulfite genomic sequencing, among the three CpGs inside the MYBPHL enhancer, CpG1 was significantly hypomethylated in MM cell lines (6.7-50.0%) than normal plasma cells (37.5-75.0%) (P = 0.007), which was negatively correlated with qPCR-measured MYBPHL expression. In RPMI-8226 and WL-2 cells, bearing the highest CpG1 methylation, 5-azadC caused enhancer demethylation and expression of MYBPHL. In primary samples, higher CpG1 methylation was associated with lower MYBPHL expression. By luciferase assay, luciferase activity was enhanced by MYBPHL enhancer compared with empty vector control, but reduced by site-directed mutagenesis of each CpG. RNA-seq data of newly diagnosed MM patients showed that MYBPHL expression was associated with t(11;14). MOLP-8 cells carrying t(11;14) express the highest levels of MYBPHL, and its knockdown reduced cellular proliferation and increased cell death. Herein, as a proof-of-concept, our data demonstrated that the MYBPHL enhancer, particularly CpG1, was hypomethylated and associated with increased MYBPHL expression in MM, which was implicated in myelomagenesis.

Multiple myeloma (MM) is consistently preceded by precursor conditions recognized clinically as monoclonal gammopathy of undetermined significance (MGUS) or smoldering myeloma (SMM). We interrogate the whole genome sequence (WGS) profile of 18 MGUS and compare them with those from 14 SMMs and 80 MMs. We show that cases with a non-progressing, clinically stable myeloma precursor condition (n = 15) are characterized by later initiation in the patient's life and by the absence of myeloma defining genomic events including: chromothripsis, templated insertions, mutations in driver genes, aneuploidy, and canonical APOBEC mutational activity. This data provides evidence that WGS can be used to recognize two biologically and clinically distinct myeloma precursor entities that are either progressive or stable.

Disruption of the normal splicing patterns of RNA is a major factor in the pathogenesis of a number of diseases. Increasingly research has shown the strong influence that splicing patterns can have on cancer progression. Multiple Myeloma is a molecularly heterogeneous disease classified by the presence of key translocations, gene expression profiles and mutations but the splicing patterns in MM remains largely unexplored. We take a multifaceted approach to define the extent and impact of alternative splicing in MM. We look at the spliceosome component, SF3B1, with hotspot mutations (K700E and K666T/Q) shown to result in an increase in alternative splicing in other cancers. We discovered a number of differentially spliced genes in comparison of the SF3B1 mutant and wild type samples that included, MZB1, DYNLL1, TMEM14C and splicing related genes DHX9, CLASRP, and SNRPE. We identified a broader role for abnormal splicing showing clear differences in the extent of novel splice variants in the different translocation groups. We show that a high number of novel splice loci is associated with adverse survival and an ultra-high risk group. The enumeration of patterns of alternative splicing has the potential to refine MM classification and to aid in the risk stratification of patients.

Second-generation immunomodulatory agents, such as lenalidomide, have a more favourable side-effect profile than the first-generation thalidomide, but their optimum combination and duration for patients with newly diagnosed transplant-ineligible myeloma (ND-TNE-MM) has not been defined. The most appropriate delivery and dosing regimens of these therapies for patients at advanced age and frailty status is also unclear. The Myeloma XI study compared cyclophosphamide, thalidomide and dexamethasone (CTDa) to cyclophosphamide, lenalidomide and dexamethasone (CRDa) as induction therapy, followed by a maintenance randomisation between ongoing therapy with lenalidomide or observation for patients with ND-TNE-MM. CRDa deepened response but did not improve progression-free (PFS) or overall survival (OS) compared to CTDa. However, analysis by age group highlighted significant differences in tolerability in older, frailer patients that may have limited treatment delivery and impacted outcome. Deeper responses and PFS and OS benefits with CRDa over CTDs were seen in patients aged ≤70 years, with an increase in toxicity and discontinuation observed in older patients. Our results highlight the importance of considering age and frailty in the approach to therapy for patients with ND-TNE-MM, highlighting the need for prospective validation of frailty adapted therapy approaches, which may improve outcomes by tailoring treatment to the individual.

INTRODUCTION/BACKGROUND:Outcomes continue to improve in relapsed myeloma as more effective treatment options emerge. We report a multicenter single-arm phase 2 trial evaluating toxicity and efficacy of the histone deacetylase (HDAC) inhibitor vorinostat in combination with bortezomib and dexamethasone. PATIENTS AND METHODS/METHODS:days 1, 4, 8, and 11; dexamethasone 20 mg orally days 1-2, 4-5, 8-9, and 11-12; vorinostat 400 mg orally days 1-4, 8-11, and 15-18 of a 21-day cycle. After receipt of a minimum of 3 cycles of therapy, participants received maintenance vorinostat (400 mg days 1-4 and 15-18 of a 28-day cycle). RESULTS:Overall response was 81.3%: complete response occurred in 4 of 16, very good partial response in 2 of 16, and partial response 7 of 16. Clinical benefit response rate was 100%; median progression-free survival was 11.9 months. A total of 75% patients experienced a dose reduction or stopped treatment as a result of intolerability. CONCLUSION/CONCLUSIONS:Although toxicity and dose reductions were observed, this study demonstrates that the combination of vorinostat, bortezomib, and dexamethasone is effective in relapsed myeloma with good response rates, suggesting there is an ongoing rationale for further optimization of HDAC inhibitor-based combinations in the treatment of myeloma to improve tolerability and enhance efficacy.