Daisuke Miura

Introduction Carfilzomib (K or Cfz) is a widely used second-generation proteasome inhibitor for patients with multiple myeloma (MM). However, despite the numerous positive clinical results, there were only a few "real-world" studies, particularly among elderly patients. Avoiding Cfz for the elderly may be based on a potential selection bias to avoid rare but serious cardiovascular adverse events (CVAEs) associated with Cfz. Moreover, although Cfz-associated thrombotic microangiopathy (TMA) has been recently recognized, the incidence rate of TMA varied from less than 1% to 5.0%. To determine the efficacy of Cfz and occurrence of CVAEs in the elderly patients and the incidence of TMA, we reviewed 96 patients, including 28 elderly patients (aged ≥76 years) at our center. All participants or their family members provided written informed consent for inclusion in the study. The study was conducted according to the Declaration of Helsinki and approved by the ethical review board of our institute. Methods Cfz was administered in the same protocol as in each clinical trial. The choice of the Cfz regimen and the criteria for dose reduction, including dexamethasone use, were based on the patient's background and discretion of the treating physician. Severe CVAEs were defined as events of grade ≥3 including heart failure, acute coronary syndrome, relative reduction in the left ventricular ejection fraction ≥20% from baseline, QT prolongation (corrected QT: ≥501 ms), and hypertension (systolic blood pressure of ≥160 mm Hg and/or diastolic blood pressure of ≥100 mm Hg, requiring two or more additional intensive medications than before) that were observed within three months after the initiation of Cfz therapy. The diagnosis of TMA was made as follows: when clinical findings were consistent with microangiopathic hemolytic anemia, such as thrombocytopenia, progressive anemia with schistocytes, elevated lactate dehydrogenase, and other differential diseases, including bacteremia or tumor progression, could be excluded. Results The patients' median age at Cfz initiation was 71 (range, 30-91) years. In total, 96 (100%), 86 (89.6%), 22 (22.9%), and 23 (23.9%) patients received bortezomib, lenalidomide, daratumumab, and autologous stem cell transplantation before Cfz therapy. Until the end of the study, 13 CVAEs (13.5%) of grade ≥3 were observed, including 2 (11.1%), 1 (11.1%), and 10 (15.2%) in patients who received Kd (Cfz and dexamethasone), DKd (Daratumumab, Cfz, and dexamethasone), and KRd (Cfz, lenalidomide, and dexamethasone), respectively. Despite the use of appropriate supportive care, grade ≥3 AEs resulting in Cfz withdrawal were noted in 25 patients: CVAEs in 11, thrombocytopenia in 4, TMA in 3, and infection in two patients. Notably, one patient with end-stage myeloma who received KRd 20/27 mg/m 2 died of CVAE on day 10 of cycle 1. At Cfz initiation, 28 patients were aged 76-80 (n=14) and ≥81 years (n=14) (Fig. 1). Three elderly patients had severe CVAEs (10.7%). The median numbers of prior chemotherapy to Cfz, time to next treatment, and overall survival from Cfz initiation were 2.5, 28.0, and 41.1 months, respectively. Although 10 patients (35.7%) discontinued Cfz therapy due to disease progression, only four patients (14.3%) discontinued Cfz owing to grade ≥3 AEs, including TMA (n = 1) and CVAEs (n = 3). Overall, five patients (5.2%) showed TMA. All patients received Kd-based regimens upon TMA development (Kd, n = 2 and DKd, n = 3). The median age of the patients who developed TMA was 74 years, and the Cfz dose was 20/27 in 1, 20/36 in 1, and 20/56 mg/m 2 in three patients. Although three patients developed TMA during the first Cfz cycle (on days 11, 16, and 21, respectively), two patients received KRd therapy before the Kd therapy that caused TMA. Two patients required temporary dialysis and four patients discontinued Cfz therapy. Eculizumab was administered in a patient and a kidney biopsy showed that the lumen of most glomerular capillaries was occluded by fibrin thrombi (Fig. 1). Furthermore, the vessel in the vascular pole of the glomerulus had necrotic lesions, suggesting drug-induced and complement-mediated TMA. Conclusion Cfz could be used safely in the elderly patients. The incidence of CVAEs by Cfz in elderly patients was similar to that in the entire cohort. The incidence of TMA was 5.2%, and Cfz-induced TMA should be carefully considered, particularly in patients using high-dose Cfz. Figure 1 Figure 1. Disclosures: No relevant conflicts of interest to declare.

Introduction. Translocations involving chromosome 14 at band q32, the immunoglobulin heavy chain (IgH) locus, are considered to be the most important initiating events for the development of multiple myeloma (MM). Among the IgH translocations in MM, t(11;14)(q13;q32) is the most frequently reported, and associated with a lymphoplasmacytic morphology. This translocation have been traditionally considered as standard-risk chromosomal abnormality compared to other translocations such as t(4;14) or t(14;16), although some controversies on the prognostic impact of this translocation still remain. This study aimed to clarify the clinical and prognostic impact of t(11;14) in Japanese patients in relation to other clinical variables such as immunophenotype of the tumor cells, other cytogenetic abnormalities, and use of stem cell transplantation (SCT). Patients and methods. Among the 244 consecutive patients with newly diagnosed MM, treated at Kameda Medical Center between April 2009 and July 2019, 234 patients, having cytogenetic analysis data (including t(11;14), t(4;14), t(14;16), and del(17p) by interphase fluorescence in situ hybridization (iFISH)) fully available, were included in this study. Data regarding the patients' clinical and laboratory characteristics, including the International Staging System (ISS), immunophenotype of the tumor cells, baseline circulating plasma cells (CPCs), treatment responses, disease progression, and survival status, were collected. iFISH was performed with CD138-purified bone marrow plasma cells, and the cut off values for translocation were ≥ 10% and for del(17p) ≥ 20%. Using multicolor flow cytometry, surface marker analysis of bone marrow samples and quantification of pre-treatment CPCs on peripheral blood mononuclear cells were simultaneously performed. CPCs were reported as the percentage of total mononuclear cells. Patients were considered to be negative for clonal CPCs at a sensitivity of 10⁻⁴ (0.01%) clonal plasma cells for all events evaluated. Results. The incidence of patients harboring t(11;14) was 24.4% (n = 57); t(11;14) was detected significantly high in light-chain-only subtypes (P < 0.001). We compared clinical characteristics of patients carrying t(11;14) with others. Myeloma cells with t(11;14) were associated with negative expression of CD56 (P < 0.001), CD117 (P = 0.046), and CD200 (P = 0.006), and positive expression of CD20 (P = 0.01) and CD81 (P = 0.035). Patients with t(11;14) were associated with positive CPCs (P = 0.011). In order to focus on the impact of t(11;14), we divided the patients into 4 groups: (A) no specific cytogenetic abnormality listed above (n = 137), (B) t(11;14) group (n = 57), (C) t(4;14) or t(14;16) group (n = 29), and (D) del(17p) only (n = 10), and the clinical characteristics and survival of the patients were compared across the three groups (A), (B), and (C). Almost all the patients (> 95%) in this cohort received bortezomib-based therapy. Median progression-free survival (PFS) and overall survival (OS) of patients in (A), (B), and (C) groups were 55.6, 34.2, and 30.2 months (m) (A vs. B, P = 0.036, and A vs. C, P = 0.031), and not reached, 51.2, and 79.8 m (A vs. B, P = 0.11, and A vs. C, P = 1.00), respectively. However, patients harboring t(11;14) were further divided into CD20-positive and -negative groups, the latter having poor prognosis (36.1 vs. 26.7, P = 1.0 for median PFS, and not reached vs. 44.2, P = 0.029 for median OS). Compared to other groups, patients without CD20 expression had significantly shorter OS (vs. A, vs. B, P = 0.024, 0.035, respectively), whereas those with CD20 expression tended to have longer OS, without statistical significance (Figure 1).Univariate analysis revealed ISS stage III, creatinine > 2.0 mg/dL, use of SCT, t(11;14) without CD20 expression, and age ≥ 70 years to be associated with shorter OS, whereas multivariate analysis demonstrated ISS stage III, use of SCT, and t(11;14) without expression CD20 (HR 1.88; 95% CI 1.10-3.21; P = 0.021) to be independent prognostic factors for poor OS. Conclusions. Our findings demonstrated that patients harboring t(11;14) had distinct clinical and immunophenotypic characteristics, two subsets of the disease entities with a clearly different survival according to CD20 expression.

Background: CD38 is highly expressed on plasma cells and is a good target for multiple myeloma (MM) therapies. Daratumumab (DARA), a humanized antibody to CD38, has emerged as a promising treatment for MM. DARA targets CD38-expressing myeloma and non-plasma cells, including CD38-positive (CD38⁺) regulatory T (Treg) cells. To investigate the mechanism of action of DARA, we analyzed baseline CD38 expression levels and lymphocyte subsets, including CD38⁺ Treg cells, before and after DARA treatment. Methods: This study comprised 32 patients with relapsed/refractory MM, who were treated with DARA at our Center and were followed up for more than one cycle of the drug. Peripheral blood and bone marrow samples were analyzed before and during treatment. Using flow cytometric analysis, CD38 expression (mean fluorescence intensity (MFI)) and lymphocyte subsets (CD4/CD8 T cells, natural killer (NK) cells, and Treg cells) were evaluated. Treg cells were identified as a fraction of the CD4⁺CD25^highCD127^dim population. Results: The median age of the patients was 78 years (range, 53-92 years). Twenty-two patients (69%) had received more than three prior therapies. Patients received a median of four prior lines of therapy (range, 2-11 prior therapies). All patients were refractory to their last line of therapy, and 89% were refractory to both proteasome inhibitors (PIs) and immunomodulatory drugs (IMiDs). Eight patients (25%) received a PI-based DARA-containing regimen, 21 (66%) received an IMiD-based DARA-containing regimen, and 3 (9%) received other DARA-containing regimens. Twenty patients (63%) had a partial response (PR) or better (responders), whereas 12 patients (37%) did not respond to the drug (non-responders). The pretreatment levels of CD38 MFI were significantly higher in responders than in non-responders (p < 0.0005). Before treatment, the absolute number of CD38⁺ Treg cells was significantly higher in responders (median, 12.3 cells/µL; range, 5.1-37.3 cells/µL) than in non-responders (median, 4.5 cells/μL; range, 1.1-12.8 cells/µL, p = 0.001), but absolute Treg cell numbers were not associated with DARA response. CD38⁺ Treg cells were depleted in all treated patients, but CD38-negative Treg cell numbers remained relatively stable after DARA treatment. The absolute CD8⁺ T-cell numbers were significantly increased after DARA treatment (236.1 ± 146.2 vs. 388.6 ± 183.4/μL, p = 0.002). In addition, the absolute HLA-DR⁺ activated T-cell numbers were also significantly increased (p = 0.002). However, the increased numbers of CD8⁺ and HLA-DR⁺ T cells were not associated with clinical responses. The numbers of CD56⁺ NK cells were immediately depleted in all treated patients. As a control, we also examined the changes in lymphocyte subsets in patients treated with elotuzumab, the first approved monoclonal antibody for MM treatment. However, there was no change in CD38⁺ Treg and total Treg cell numbers. Next, to investigate the role of CD38⁺ Treg cells in disease progression, we analyzed the frequencies of Treg cells in healthy volunteers and in patients with monoclonal gammopathy of undetermined significance, smoldering MM, newly diagnosed MM, and relapsed MM. The CD38⁺ Treg cells were significantly higher in the relapsed MM group than in the other disease or control groups, suggesting that CD38⁺ Treg cells may play an important role in the progression of MM. Finally, we investigated the CD38 expression and frequency of CD38⁺ Treg cells in durable responders. Among 20 responders, 13 patients showed a long-lasting response (>6 months) or deepening response (defined as durable responders). The absolute number of CD38⁺ Treg cells was significantly higher in the durable responders (p = 0.009). On the other hand, the CD38 MFI of myeloma cells was not associated with a durable response. Conclusions: Pretreatment levels of the CD38 MFI could be a predictive marker for the early response to DARA treatment. Moreover, the frequency of CD38⁺ Treg cells present before treatment could also serve as a durable-response marker. These results suggest that the depletion of CD38⁺ Treg cells could contribute to some immunological mechanism of DARA. This study provides evidence to support multiple mechanisms of action for DARA, including antibody-dependent cell-mediated cytotoxicity and immunomodulatory effects.