Faculty Bibliography

Early alterations within the bone marrow microenvironment that contribute to the progression of multiple myeloma (MM) from its precursor stages could hold the key to identifying novel therapeutic approaches, yet the intrinsic variability in cellular populations between patients together with differences in sample processing and analysis methods have made it difficult to identify consistent changes between datasets. Here, we used single-cell RNA sequencing of BM cells from precursor stages, monoclonal gammopathy of unknown significance (MGUS), smoldering MM (SMM) and newly diagnosed MM and analyzed our data in combination with a previously published dataset that used a similar patient population and sample processing. Despite vast interpatient heterogeneity, some alterations were seen consistently in both datasets. We identified changes in immune cell populations as disease progressed that were characterized by a substantial decrease in memory and naïve CD4 T cells and an increase in CD8+ effector T cells and T-regulatory cells. These alterations were further accompanied by an enrichment of non-clonal memory B cells and an increase of CD14 and CD16 monocytes in MM compared to its precursor stages. These results provide crucial information of the immune changes associated with the progression to clinical MM and can help to develop immune based strategies for patient stratification and early therapeutic intervention.

IgD myeloma is a subtype often considered to have adverse features and inferior survival but there is a paucity of data from large clinical studies. We compare the clinical characteristics and outcomes of IgD myeloma patients from UK Phase III myeloma trials analysed in two groups; old (1980-2002) and recent (2002-2016) clinical trials, based on the time of adoption of novel myeloma therapies. IgD myeloma patients comprised 44/2789 (1.6%) and 70/5773 (1.2%) of the old and recent trials respectively. Overall, IgD myeloma was associated with male predominance, low-level paraproteinemia (<10g/l) and lambda light chain preference. The frequency of ultra-high risk cytogenetics was similar in IgD myeloma compared with other subtypes (4.3% vs 5.3%, p>0.99). Despite the old trial series being a younger group (median age: 59 years vs 63 years, p=0.015), there was a higher frequency of bone lesions, advanced stage at diagnosis, worse performance status and severe renal impairment compared with the recent trials. Furthermore, the early mortality rate was significantly higher for the old trial series (20% vs 4%, p=0.01). The overall response rate following induction therapy was significantly higher in the recent trials (89% vs 43%, p<0.0001) and this was consistent with improved median overall survival (48 months; 95% CI 35-67 months vs 22 months, 95% CI 16-29 months). Survival outcomes for IgD myeloma have significantly improved and are now comparable to other myeloma types due to earlier diagnosis, novel therapies and improved supportive care. (Myeloma IX International Standard Randomised Controlled Trial Number: 68454111, Myeloma XI International Standard Randomised Controlled Trial Number: 49407852).

Deciphering Multiple Myeloma evolution in the whole bone marrow is key to inform curative strategies. Here, we perform spatial-longitudinal whole-exome sequencing, including 140 samples collected from 24 Multiple Myeloma patients during up to 14 years. Applying imaging-guided sampling we observe three evolutionary patterns, including relapse driven by a single-cell expansion, competing/co-existing sub-clones, and unique sub-clones at distinct locations. While we do not find the unique relapse sub-clone in the baseline focal lesion(s), we show a close phylogenetic relationship between baseline focal lesions and relapse disease, highlighting focal lesions as hotspots of tumor evolution. In patients with ≥3 focal lesions on positron-emission-tomography at diagnosis, relapse is driven by multiple distinct sub-clones, whereas in other patients, a single-cell expansion is typically seen (p < 0.01). Notably, we observe resistant sub-clones that can be hidden over years, suggesting that a prerequisite for curative therapies would be to overcome not only tumor heterogeneity but also dormancy.

The multiple myeloma treatment landscape has changed dramatically. This change, paralleled by an increase in scientific knowledge, has resulted in significant improvement in survival. However, heterogeneity remains in clinical outcomes, with a proportion of patients not benefiting from current approaches and continuing to have a poor prognosis. A significant proportion of the variability in outcome can be predicted on the basis of clinical and biochemical parameters and tumor-acquired genetic variants, allowing for risk stratification and a more personalized approach to therapy. This article discusses the principles that can enable the rational and effective development of therapeutic approaches for high-risk multiple myeloma.

Smoldering multiple myeloma (SMM) is a precursor condition of multiple myeloma (MM) with significant heterogeneity in disease progression. Existing clinical models of progression risk do not fully capture this heterogeneity. Here we integrate 42 genetic alterations from 214 SMM patients using unsupervised binary matrix factorization (BMF) clustering and identify six distinct genetic subtypes. These subtypes are differentially associated with established MM-related RNA signatures, oncogenic and immune transcriptional profiles, and evolving clinical biomarkers. Three genetic subtypes are associated with increased risk of progression to active MM in both the primary and validation cohorts, indicating they can be used to better predict high and low-risk patients within the currently used clinical risk stratification models.

The prognostic significance of minimal residual disease (MRD) detection in multiple myeloma (MM) is well established. Understanding factors that predict for MRD negativity such as tumor burden, cytogenetic and immune- related biomarkers may enable us to improve outcome prediction at diagnosis, and in the future move toward tailored treatment approaches.