Sherbenou, Daniel W

The treatment landscape for multiple myeloma (MM) is evolving rapidly and includes several new options. The management must be tailored to the individual. The NCCN Guidelines for MM provide a framework to base decisions regarding diagnosis, workup, treatment, and follow-up of both newly diagnosed and previously treated relapsed/refractory MM. This manuscript outlines the recommendations from NCCN Guidelines for MM specific to newly diagnosed MM (NDMM).

Abstract Multiple myeloma is a malignancy of clonally expanded plasma cells shaped by complex interactions with the immune microenvironment (IME). To investigate immune correlates of treatment response and disease progression, we conducted multi-omics profiling including CD138neg single-cell RNA sequencing of 243 bone marrow samples from 102 patients (631,226 cells) and CD138pos bulk RNA and whole-genome sequencing from 209 samples. In longitudinal analyses, interferon-γ signaling associated with markers of impaired T-cell memory after autologous stem cell transplant, whereas naïve B-cell abundance and immunoglobulin diversity correlated with improved progression-free survival (HR = 0.48; P = 2.3e−4). At disease progression, multiple myeloma cells upregulated cancer–testis antigens (CTAg) and immune effector genes, with concurrent B-cell depletion, enrichment of myeloid-derived suppressor cell expression, and phenotypic T-cell exhaustion. These findings highlight dynamic immune–tumor interactions, identifying naïve B-cell reconstitution as a biomarker of durable response and CTAgs as potential targets for high-risk disease at progression. Significance: Longitudinal profiling of multiple myeloma and the IME revealed dynamic immune–tumor interactions across the disease course. Altered expression in CD8+ T cells limited memory phenotype after transplant, whereas naïve B-cell recovery associated with sustained treatment response. At progression, CTAg expression associated with immunosuppression, revealing novel mechanisms of immune dysregulation.

Abstract Background: Prolonged cytopenias are a well-recognized complication following CAR-T therapy, leading to increased morbidity and healthcare utilization. Autologous SCB offers a potential strategy to promote hematologic recovery. We conducted a retrospective multi-institutional analysis across 18 centers comparing outcomes of SCB versus supportive care alone in RRMM patients who experienced prolonged cytopenias >30 days after CAR-T infusion. Methods: Patients were included if they received SCB within 1 year after commercial CAR-T between 6/2021 and 3/2024. To identify matched controls, we reviewed other CAR-T recipients from the same consortium and selected those with an absolute neutrophil count (ANC) of <0.72x109/L and platelet count of <21K at day 30 post-infusion-thresholds representing the 75th percentile of cytopenia severity in the SCB cohort. These criteria ensured control patients had comparable hematologic toxicity but without SCB. Hematologic recovery in the SCB cohort was assessed using the CIBMTR engraftment criteria. For the non-SCB (nSCB) group, cell counts were analyzed cross-sectionally at day 90 post-CAR-T and compared to the SCB cohort with Kruskal Wallis tests. Progression-free survival (PFS) and overall survival (OS) were evaluated using Kaplan Meier methods. Results: Of the 590 CAR-T recipients, 91 patients (15.4%) developed prolonged cytopenias; 39 patients received SCB and 52 did not. SCB patients more frequently had ISS stage III disease (23.1% vs. 11.5%), exrtamedullary disease (59% vs. 46.2%) and penta-refractory status (43.6% vs. 34.6%). The median number of prior lines of therapy was 6 in both cohorts. Thirteen patients (33.3%) in the SCB and 11 (21.2%) in the nSCB received high intensity infusional chemotherapy (DCEP/PACE/HyperCVAD). Pre-CAR-T cytopenias tended to be less frequent in the SCB vs. nSCB cohort: ANC <1000 in 5.1% vs. 13.5%, Hgb <8 in 23.1% vs. 21.2%, and platelets <50K in 28.2% vs. 40.4%. Median plasmacytosis in the bone marrow prior to CAR-T in the SCB group was 35% and 47.5% in the nSCB group. In the SCB cohort, 2 patients harbored DNMT3A mutations, one of whom had CCUS. Ide-cel was administered in 64.8% and cilta-cel in 35.2% of all patients. The rates and grades of cytokine release syndrome did not differ between groups. Six patients (15.4%) had HLH in the SCB group vs. none in the control group. All (100%) SCB patients received growth factor support; 58% also received TPO agonists. In the nSCB group, 43 patients (82.7%) received growth factor, and 16 patients (30.8%) received TPO agonists. Out of 24 pre-SCB bone marrow biopsies available, only 1 patient had relapsed MM while the remainder had hypocellular marrows. Median CD34+ cell dose was 2.93 million/kg (range: 1.76-23.55) administered at a median of 53 days post-CAR-T (range 24-265). All but one patient (97.4%) in the SCB group achieved hematologic recovery; median time to recovery was 24 days (range 9-87). No new toxicities attributable to SCB were observed. On day 90 post CAR-T infusion, SCB patients had higher median ANC (2.12 vs. 1.59x109/L, p=0.277), Hgb (10.6 vs. 8.7g/dL, p=0.002), and platelet counts (135 vs. 35K/L (p<0.001). Minimal residual disease negativity was achieved in 82.4% (SCB) vs. 83.3% (nSCB). Infections occured in 53.8% and 48.1% of SCB and nSCB cohorts. All serious infections occurred prior to SCB. There were 12 deaths in the SCB group (7 from disease progression, 2 from infection, 1 from neurotoxicity (NT), and 1 unknown) and 27 in the nSCB group (22 from progression, 3 from infection, 1 from HLH, 1 from NT). After a median follow-up period of 12.6 months in the SCB cohort and 11.6 months in the nSCB arm, the mPFS was 11.0 months and 8.2 months, respectively. The mPFS was 10.6 months (SCB) and 5.8 months (nSCB) (p=0.216), and 11.0 months (SCB) and 10.9 months (nSCB), for ide-cel and cilta-cel treated-patients, respectively. Median OS was not reached vs.12.3 months in the SCB vs. nSCB groups, respectively. Conclusion: Overall, SCB was safe and effective in promoting rapid hematologic recovery in nearly all patients. Compared to controls, SCB recipeints had significantly higher Hgb and platelet levels by day 90 post-CAR-T infusion. SCB was associated wih a near doubling of PFS in patients who received ide-cel, though interpretation is limited by non-randomized design and small sample size. Further study is needed to optimize paient selection, timing, and integration of SCB into CAR-T care.

Abstract Multiple myeloma (MM) is an incurable malignancy of clonally expanded plasma cells shaped by complex interactions with the immune microenvironment. To investigate immune factors driving treatment response and resistance, we conducted multi-omics profiling including CD138 neg single-cell RNA sequencing of 243 bone marrow samples from 102 patients (631,226 cells) and CD138 pos bulk RNA and whole-genome sequencing from 209 samples. Longitudinal analyses revealed that interferon gamma signaling impairs T cell memory after autologous stem cell transplant, while naïve B cell abundance and immunoglobulin diversity correlated with improved progression-free survival (HR = 0.48, p = 2.3e -4 ). At disease progression, MM cells upregulated cancer-testis antigens and immune effector genes, with concurrent B cell depletion, enrichment of myeloid-derived suppressor cell genes in monocytes, and T cell exhaustion. These findings highlight dynamic immune-tumor interactions, identifying naïve B cell reconstitution as a biomarker of durable response, and cancer-testis antigens as potential targets for high-risk disease at progression. Statement of Significance Longitudinal profiling of multiple myeloma and the immune microenvironment revealed dynamic immune-tumor interactions across the disease course. Dysfunctional CD8⁺ T cells limited memory formation post-transplant, while naïve B recovery associated with sustained treatment response. At progression, cancer-testis antigen expression associated with immunosuppression, revealing novel mechanisms of immune escape.

The NCCN Guidelines for Multiple Myeloma (MM) provide recommendations for diagnosis, initial workup, treatment, follow-up, and supportive care for patients with MM. These NCCN Guidelines Insights highlight the important updates and changes specific to systemic therapy for patients with newly diagnosed as well as previously treated MM included in Version 1.2025 of the NCCN Guidelines for MM.

The treatment of Waldenström macroglobulinemia/lymphoplasmacytic lymphoma (WM/LPL) has evolved to include several new options. The NCCN Guidelines for WM/LPL provide a framework on which to base decisions regarding diagnosis, treatment, assessment of response to treatment, and follow-up of both newly diagnosed and previously treated WM/LPL.

The treatment of relapsed/refractory multiple myeloma (MM) has evolved to include several new options. These include new combinations with second generation proteasome inhibitors (PI); second generation immunomodulators, monoclonal antibodies, CAR T cells, bispecific antibodies, selinexor, venetoclax, and many others. Most patients with MM undergo several cycles of remissions and relapse, and therefore need multiple lines of combination therapies. Selecting treatment options for relapsed/refractory MM requires consideration of resistance status to specific classes, and patient-specific factors such as age and other comorbidities should be considered. The NCCN Guidelines for MM provide a framework on which to base decisions regarding workup, treatment, and follow-up of newly diagnosed and previously treated MM. This manuscript outlines the recommendations from NCCN Guidelines for MM specific to relapsed/refractory disease.

Abstract Background: Protein production and homeostasis are critical to life and death decisions of malignant plasma cells in multiple myeloma (MM). While protein homeostasis has been targeted effectively with proteasome inhibitors in this disease, inhibition of protein production has not been clinically tested. Protein translation inhibition represents an immediately available avenue, with the agent omacetaxine mepesuccinate (Oma). Recent in vivo and ex vivo work illustrates the broad sensitivity MM cells have to Oma, irrespective of proteasome inhibitor (PI) or immunomodulatory (IMiD) drug treatment exposure (Walker et al. Clinical Cancer Research, 2021). High levels of baseline protein translation, compared to other cells in the bone marrow, serves as a biomarker of high Oma sensitivity in MM patient samples. Based on this, we hypothesized that Oma treatment in MM may lead to eventual drug resistance through the downregulation of protein synthesis. To test this, we evaluated the effects of long-term Oma treatment on MM cells, by establishing resistance in two human MM cell lines and comparing them to their isogenic parental lines. Methods: Omacetaxine resistance was established by dose escalation in MM cell lines NCI-H929 and MM1S, with concentrations gradually increased over 80 weeks to 84 nM and 52 nM, respectively. Resistance was confirmed via CellTiter-Glo after 96 h incubations. Translation rates were measured by incorporation of OP-Puromycin. Flow cytometry was used for cell cycle analysis. Mass cytometry (CyTOF) was performed on a Fluidigm Helios system with a 35-marker panel. Cell morphology was examined by confocal microscopy using a Zeiss LSM780 spectral microscope with DAPI and Mitotracker stains. Cell line xenograft studies were performed using NSG mice engrafted via IV tail injection. Results: Resistant cell lines H929-R and MM1S-R displayed decreased cytotoxicity to Oma, with EC50 >100 nM after 96 h treatment, compared to parental line sensitivity of 24 nM for MM1S and 54 nM for H929 (Fig 1A and 1B). Next, we evaluated baseline translation rates for both parental and resistant lines. As hypothesized, H929 cells significantly downregulated translation after acquiring Oma resistance, but MM1S cells actually significantly upregulated protein synthesis (n = 3, p < 0.001 for both lines, Fig 1C). Interestingly, MM1S-R cells showed global phenotypic changes from the parental line based on UMAP analysis of CyTOF results, whereas H929-R appeared similar to its isogenic line (Fig 1D). The most altered protein was the transcription factor XBP1s, which was elevated in MM1S-R cells compared to parental (Fig 1E). An increased percentage of aneuploidy cells was observed in both resistant lines compared to the parental lines, indicating genomic pressure on both (Fig 1F). Consistent with this, confocal microscopy showed the emergence of multi-nucleated and pleomorphic cells in the Oma resistant lines compared to parental (Fig 1G). Finally, both resistant lines showed a surprising extended survival in an untreated MM NSG xenograft model. Mice engrafted with either H929-R or MM1S-R had a significant survival advantage over their parental cell lines (p = 0.0019, p = 0.0014, Fig 1G and 1H). Median survival was 119 days for H929-P and unreached for H929-R mice, MM1S was 47 and 68 days respectively. Conclusion: After prolonged exposure to Oma, cell lines H929 and MM1S displayed unique characteristics compared to their parental lines, including changes in protein translation rates, drug sensitivities, aneuploidy, and in vivo growth characteristics. Once resistant to Oma, H929 cells downregulated translation, similar to published patient sample data. Conversely, MM1S cells upregulated translation and displayed a more complex phenotypic shift, including an upregulation of XPB1s, an indication of increased unfolded protein response. Much like PIs, we believe Oma disrupts the delicate proteostasis intrinsic to MM cells, putting them on the defensive. Both Oma resistant cell lines exhibited a stressed cell state evident through their decline of in vivo fitness and an increase in poly-aneuploidy. Ongoing research with these cell lines will evaluate transcriptional changes, continuing to advance our understanding of Oma sensitivity and resistance in multiple myeloma. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.