Peripheral Immunotype Correlates with Minimal Residual Disease Status and Is Modulated by Immunomodulatory Drugs in Multiple Myeloma.

Data indicate reversal of immune dysfunction with active treatment; however, the precise contribution of specific immune effector and immune suppressor components to achieve a minimal residual disease (MRD) state and immunomodulatory drug-mediated immunomodulatory effects in multiple myeloma (MM) patients remains poorly understood. In this prospective proof-of-principle study we sought to determine the dynamic alterations in natural killer (NK), NK-T, and T cells, including maturation and activating/inhibitory repertoire associated with MRDpos versus MRDneg status after autologous stem cell transplantation (ASCT) and during lenalidomide-based maintenance therapy. Of the 46MM patients enrolled, 36 had bone marrow MRD assessment 60+ days post-ASCT, 30 had longitudinal blood immunotyping during maintenance (pretherapy and after cycles 1, 3, and 6), and 20 had both MRD assessment and longitudinal immunotyping. Multicolor flow cytometry was used for MRD and immunotyping. Although the absolute number of NK cells was significantly lower in patients with MRDpos response, phenotypically NK cells in these patients displayed higher expression of activating receptors KIRDS4 and decreased expression of inhibitory molecules NKG2A compared with the MRDneg group. Furthermore, we observed significantly lower frequencies of T cells displaying KIR3DL1 in MRDpos versus MRDneg patients. Longitudinal immunotyping during lenalidomide maintenance showed loss of mature NK effector function, augmentation of NK-T effector function, and acquisition of PD1 independent anergic state. Our findings also suggest skewing of T cells toward an exhausted state during the maintenance phase in MRDpos patients. Put together, these observations provide a distinctive signature for MRDneg and MRDpos groups. These data support exploration of immune profiling in prospective clinical trials according to MRD-defined responses to identify patients that may benefit from maintenance intensification/modification or maintenance withdrawal.

A Clinical and Correlative Study of Elotuzumab, Carfilzomib, Lenalidomide, and Dexamethasone (Elo-KRd) for Lenalidomide Refractory Multiple Myeloma in First Relapse.

INTRODUCTION: Treatment of patients with multiple myeloma (MM) in first relapse remains a challenge. This phase II study combined elotuzumab (Elo) with carfilzomib, lenalidomide, and dexamethasone (KRd) for treatment of MM in first relapse with the aim of improving efficacy. METHODS: Enrolled patients received Elo-KRd induction for 4 cycles, and Elo-lenalidomide maintenance until progression. The primary endpoint was VGPR or better (≥VGPR) postinduction. Secondary endpoints were MRD by flow cytometry, OS, PFS, and safety. Correlatives included characterization of the impact of Elo-KRd on NK and T cell subsets via flow cytometry. Target accrual of 40 patients was not met due to COVID-19 pandemic. RESULTS: Of 15 patients enrolled, 10 (67%) had high-risk features (del17p, t[4;14], t[14;16], 1q gain/amplification, plasma cell leukemia, extramedullary MM, or functional high risk), 12 (80%) were lenalidomide-refractory, and 5 (33.3%) bortezomib-refractory. Postinduction ≥VGPR was 7/15 (46.7%) and MRD-negative (10-5) rate 20%. Overall response during study was 80%, including ≥VGPR as best response of 53.3%. At median follow-up of 28.2 (range, 3.8 to 44.2) months, the median PFS was 11.5 months (95% CI 1.9, 18), and median OS not reached (95% CI 10.1, NA). No new safety concerns were reported. Elo-KRd treatment did not augment NK cell distribution or activity in blood or bone marrow. Effector CD4+ and CD8+ T cells significantly decreased postinduction, with concomitant acquisition of T central memory phenotype, particularly at a high rate in ≥VGPR group. CONCLUSION: A short course of Elo-KRd induction followed by Elo-lenalidomide maintenance demonstrated activity in predominantly lenalidomide-refractory and / or high-risk MM. The results with this well-tolerated combination are comparable to other contemporary approved triplet combinations.

Ex vivo efficacy of BCMA-bispecific antibody TNB-383B in relapsed/refractory multiple myeloma.

TNB-383B is a fully human BCMA-targeting T-cell engaging bispecific monoclonal antibody (T-BsAb). We assessed ex vivo efficacy of this drug to mediate killing of bone marrow mononuclear cells (BMMCs) freshly isolated from 10 patients with relapsed multiple myeloma (MM). BMMC were treated ex vivo with TNB-383B at doses ranging from 0.001-1 µg. Plasma cell (PC) lysis, viability, BCMA expression, CTL distribution, and degranulation were assessed by flow cytometry. Cytokine response to TNB-383B was quantified by multiplex protein assay. Dose-dependent PC lysis was triggered in all cases by TNB-383B at doses as low as 0.001 µg (P = .0102). Primary MM cells varied in BCMA expression. High BCMA+ PC count correlated with increased PC lysis (P = .005) and significant CTL degranulation specific to TNB-383B treatment (P = .0153 at 1 µg). High E:T ratio in bone marrow specimens led to lower viable and higher apoptotic PC compared with low E:T ratio (P < .001). Three cytokines were significantly modulated by TNB-383B: IL-2/TNFα increased by ∼4 ± 3.5-fold average (P < .005 at 1 µg) and IP10 increased by ∼50 ± 15-fold (P < .001 at 1 µg). We conclude that TNB-383B triggers primary PC lysis and CTL degranulation in a dose-dependent fashion ex vivo with no T cell expansion and mild increase of CRS-associated cytokines.

Deep sustained response to daratumumab monotherapy associated with T-cell expansion in triple refractory myeloma.

BACKGROUND: Daratumumab, a human CD38 monoclonal antibody that has direct on-tumor and immunomodulatory mechanisms of action, demonstrated clinical benefit as monotherapy or in combination with established regimens in patients with multiple myeloma with one or more prior lines of therapy. CASE PRESENTATION: A male patient, who was 70 years of age at the time of diagnosis of multiple myeloma in 2011, relapsed after five lines of therapy, including autologous stem cell transplantation. The patient's disease, which was considered high risk with a deletion of chromosome 17p, advanced quickly and was triple refractory 2 years after diagnosis leaving few treatment options. He was treated with daratumumab monotherapy in the SIRIUS clinical trial resulting in a stringent complete response and clearance of minimal residual disease. The duration of the patient's clinical response is now over 3.5 years without relapse, compared with a median of 7.6 months for similarly treated patients. The patient's immunophenotype revealed CD8+ T-cell expansion, clonal expansion of the T-cell receptor repertoire, and decreases in regulatory T cells during daratumumab therapy, suggesting a robust adaptive immune response. This immune response was still present 32 months into daratumumab therapy. CONCLUSIONS: The results from this case report showed that a patient with advanced multiple myeloma, who had exhausted all treatment options with existing regimens, mounted an ongoing, deep, and durable response to daratumumab monotherapy. Further investigation of the immunologic profile provided additional patient-level evidence of an immunomodulatory mechanism of action of daratumumab.Trial registration ClinicalTrials.gov Identifier number NCT01985126. Submitted 22 July 2013.