Identifying clinical response to daratumumab therapy in relapsed/refractory multiple myeloma using a patient-derived in vitro model.

Response to daratumumab in patients with relapsed/refractory multiple myeloma is heterogeneous, and a reliable biomarker of response is lacking. We aimed to develop a method that identifies response to daratumumab therapy. Patient-derived MM cells were collected before start of daratumumab treatment and were cultured in a hydrogel-based culture system. The extent of antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity in vitro was associated with both clinical response and progression-free survival in corresponding patients. Together, our results demonstrate that in vitro sensitivity to daratumumab therapy in a hydrogel culture with primary MM cells might be used to identify patients most likely to benefit from treatment.

Cryoglobulinemic Vasculitis in Disguise: Cryofibrinogenemia as Variant of Monoclonal Gammopathy of Renal Significance.

Monoclonal gammopathy with cryoactivity (ie, cryoglobulins) that causes glomerulonephritis is considered within the spectrum of monoclonal gammopathy of renal significance. Cryofibrinogenemia (cryoactivity of coagulation factors) is very rarely associated with glomerulonephritis. We present a 39-year-old woman with a relapsing nephrotic syndrome. Laboratory investigation detected cryofibrinogen; the precipitate consisted of fibrinogen and a monoclonal immunoglobulin (M-protein; IgG-λ), and the latter was also detected in serum (4g/L). Initial conventional immunosuppressive therapy resulted in temporary renal remission. In view of the M-protein, subsequent therapy consisted of bortezomib/dexamethasone and high-dose melphalan followed by autologous hematopoietic stem cell transplantation, and resulted in a very good partial hematological response and temporary renal remission. However, after hematological and renal relapse, we performed unique experiments to clarify the role of the M-protein. Mixing patient serum with donor plasma resulted in cryoactivity, composed of M-protein+fibrinogen. Patient plasma deprived of M-protein did not have cryoactivity. Therefore, cryoactivity was dependent on the M-protein. We started lenalidomide, which resulted in very good partial hematological and renal remission. Thus, cryofibrinogenemia can be the consequence of an M-protein, which we suggest should be defined as monoclonal gammopathy of renal significance.

Population-Based External Validation of the EASIX Scores to Predict CAR T-Cell-Related Toxicities.

Cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) can hamper the clinical benefit of CAR T-cell therapy in patients with relapsed/refractory large B-cell lymphoma (r/r LBCL). To assess the risk of CRS and ICANS, the endothelial activation and stress index (EASIX), the modified EASIX (m-EASIX), simplified EASIX (s-EASIX), and EASIX with CRP/ferritin (EASIX-F(C)) were proposed. This study validates these scores in a consecutive population-based cohort. Patients with r/r LBCL treated with axicabtagene ciloleucel were included (n = 154). EASIX scores were calculated at baseline, before lymphodepletion (pre-LD) and at CAR T-cell infusion. The EASIX and the s-EASIX at pre-LD were significantly associated with ICANS grade ≥ 2 (both p = 0.04), and the EASIX approached statistical significance at infusion (p = 0.05). However, the predictive performance was moderate, with area under the curves of 0.61-0.62. Validation of the EASIX-FC revealed that patients in the intermediate risk group had an increased risk of ICANS grade ≥ 2 compared to low-risk patients. No significant associations between EASIX scores and CRS/ICANS grade ≥ 3 were found. The (m-/s-) EASIX can be used to assess the risk of ICANS grade ≥ 2 in patients treated with CAR T-cell therapy. However, due to the moderate performance of the scores, further optimization needs to be performed before broad implementation as a clinical tool, directing early intervention and guiding outpatient CAR T-cell treatment.

The Dutch CAR-T Tumorboard Experience: Population-Based Real-World Data on Patients with Relapsed or Refractory Large B-Cell Lymphoma Referred for CD19-Directed CAR T-Cell Therapy in The Netherlands.

The real-world results of chimeric antigen receptor T-cell (CAR-T) therapy for patients with relapsed/refractory (R/R) large B-cell lymphoma (LBCL) substantially differ across countries. In the Netherlands, the CAR-T tumorboard facilitates a unique nationwide infrastructure for referral, eligibility assessment and data collection. The aim of this study was to evaluate real-world outcomes of axicabtagene ciloleucel (axi-cel) in the Dutch population, including the thus-far underreported effects on health-related quality of life (HR-QoL). All patients with R/R LBCL after ≥2 lines of systemic therapy referred for axi-cel treatment between May 2020-May 2022 were included (N = 250). Of the 160 apheresed patients, 145 patients received an axi-cel infusion. The main reason for ineligibility was rapidly progressive disease. The outcomes are better or at least comparable to other studies (best overall response rate: 84% (complete response: 66%); 12-month progression-free-survival rate and overall survival rate: 48% and 62%, respectively). The 12-month NRM was 5%, mainly caused by infections. Clinically meaningful improvement in several HR-QoL domains was observed from Month 9 onwards. Expert-directed patient selection can support effective and sustainable application of CAR-T treatment. Matched comparisons between cohorts will help to understand the differences in outcomes across countries and select best practices. Despite the favorable results, for a considerable proportion of patients with R/R LBCL there still is an unmet medical need.

Development of a Core Set of Patient- and Caregiver-Reported Signs and Symptoms to Facilitate Early Recognition of Acute Chimeric Antigen Receptor T-Cell Therapy Toxicities.

PURPOSE: Prompt recognition of acute chimeric antigen receptor T (CAR T)-cell-mediated toxicities is crucial because adequate and timely management can prevent or reverse potential life-threatening complications. In the outpatient setting, patients and informal caregivers have to recognize and report signs and symptoms marking these acute toxicities. This study provides a core set of patient- and caregiver-reported signs and symptoms (outcomes, P/CROs) and definitions of red flags warranting immediate action to include in a daily checklist for support at home, with the goal to make outpatient post-CAR T-cell care safer, optimize patient and caregiver support, and thereby facilitating an early discharge/hospital visit reduction strategy. METHODS: We performed a systematic review of phase II/III trials of US Food and Drug Administration-approved CAR T-cell products and selected all common and severe adverse events that could be translated into a P/CRO for inclusion in a two-round modified Delphi procedure. Eleven CAR T-cell-dedicated hematologists from the Dutch CAR T-cell tumorboard representing all treating centers selected P/CROs for inclusion in the core set and defined red flags. The final core set was evaluated with patients and caregivers. RESULTS: From nine clinical trials, 457 adverse events were identified of which 42 could be used as P/CRO. The final core set contains 28 items, including five signs for measurement via wearables and two signs for caregiver-performed assessments. CONCLUSION: This study provides a core set of P/CROs that can serve as a framework for (eHealth) tools that aim to enable patients and caregivers to more effectively recognize and report signs and symptoms of acute toxicities after CAR T-cell therapy, which will enhance safe outpatient treatment monitoring.

Efficacy of retreatment with immunomodulatory drugs and proteasome inhibitors following daratumumab monotherapy in relapsed and refractory multiple myeloma patients.

This single-centre retrospective observational study analysed the efficacy of retreatment with immunomodulatory agents (IMiDs) and proteasome inhibitors (PIs) after treatment with daratumumab monotherapy in patients with relapsed and/or refractory multiple myeloma (RRMM). In total 55 patients were treated with daratumumab monotherapy between 2010 and 2017. From this group 29 (53%) IMiD-refractory patients were retreated with an IMiD after daratumumab and 6 (11%) PI-refractory patients were retreated with a PI-based regimen. For the IMiD-refractory patients the overall response rate (ORR) was 52% (15/29 patients, partial response or better) upon IMiD retreatment, whereas the ORR to PI retreatment was 67% (4/6 patients) in the PI-refractory group. The immunomodulatory effects of daratumumab may play a role in these high response rates in previously refractory patients. Due to the >6 month-long persistence of daratumumab in the plasma the subsequent therapies can effectively be considered as combination therapy. Furthermore, the excellent tolerability of daratumumab treatment may enable patients to recover from prior lines of treatment and receive full dosing of subsequent therapies. In conclusion, a high proportion of RRMM patients benefitted from retreatment with IMiDs and PIs after daratumumab treatment. These retreatment options should therefore be explored in RRMM patients progressing on daratumumab monotherapy.

The latest developments with anti-CD20 monoclonal antibodies in chronic lymphocytic leukemia.

INTRODUCTION: In more recent years, anti-CD20 monoclonal antibodies have become the backbone in the treatment of chronic lymphocytic leukemia (CLL). Historically, these antibodies were typically combined with chemotherapeutic agents. At present, therapeutic outcomes are significantly improving with the introduction of several novel targeted drugs to the clinical repertoire. AREAS COVERED: In this review, we summarize the current clinical standard together with the latest developments in the field of anti-CD20 antibodies against CLL. In addition, novel promising drugs against CLL are discussed, as well as their potential for combination with anti-CD20 monoclonal antibodies. EXPERT OPINION: At present, there are three different anti-CD20 monoclonal antibodies approved for the treatment of CLL with diverse effector mechanisms. These antibodies provide a robust foundation for combination therapy with novel molecules. Current research should be focused on reducing toxicity and reaching long-lasting remissions. There is still much to gain regarding the optimization of treatment combinations and dosing schedules for CLL. Overcoming the limitations of currently used anti-CD20 antibodies will be critical to further improve the efficacy of CLL therapy.

IL-21 and CD40L signals from autologous T cells can induce antigen-independent proliferation of CLL cells.

Chronic lymphocytic leukemia (CLL) cells multiply in secondary lymphoid tissue, but the mechanisms leading to their proliferation are still uncertain. In addition to B-cell receptor (BCR)-triggered signals, other microenvironmental factors might well be involved. In proliferation centers, leukemic B cells are in close contact with CD4(+)CD40L(+) T cells. Therefore, we here dissected the signals provided by autologous activated T cells (Tact) to CLL cells. Although the gene expression profile induced by Tact was highly similar to that induced by sole CD40 signaling, an obvious difference was that Tact induced proliferation of CLL cells. We determined that stimulation with only CD40L+IL-21 was sufficient to induce robust proliferation in CLL cells. We then defined an interleukin (IL)-21-induced gene signature in CLL, containing components of Janus kinase/signal transducer and activator of transcription and apoptosis pathways, and this signature could be detected in lymph node (LN) samples from patients. Finally, we could detect IL-21 RNA and protein in LN, and IL-21 production ex vivo by LN CD4(+)CXCR5(+) follicular helper T cells. These results indicate that in addition to BCR signaling, activated T cells might contribute to CLL cell proliferation via CD40 and IL-21. Targeting these signaling pathways might offer new venues for treatment of CLL.

CD40 stimulation sensitizes CLL cells to lysosomal cell death induction by type II anti-CD20 mAb GA101.

Sensitivity of chronic lymphocytic leukemia (CLL) cells to anti-CD20 mAbs is low and, therefore, the efficacy of monotherapy with current anti-CD20 mAbs is limited. At present, it is not known whether sensitivity of CLL cells to CD20 mAbs is modulated by microenvironmental stimuli. We have shown previously that in vitro CD40 stimulation of peripheral blood-derived CLL cells results in resistance to cytotoxic drugs. In the present study, we show that, in contrast, CD40 stimulation sensitizes CLL cells to the recently described novel type II anti-CD20 mAb GA101. Cell death occurred without cross-linking of GA101 and involved a lysosome-dependent mechanism. Combining GA101 with various cytotoxic drugs resulted in additive cell death, not only in CD40-stimulated CLL cells, but also in p53-dysfunctional CLL cells. Our findings indicate that GA101 has efficacy against chemoresistant CLL, and provide a rationale for combining cytotoxic drugs with anti-CD20 mAbs.

Enhanced formation and survival of CD4+ CD25hi Foxp3+ T-cells in chronic lymphocytic leukemia.

Recently, it has been described that patients with chronic lymphocytic leukemia (CLL) have increased numbers of regulatory T (T(reg)) cells. In the present study, we analysed the mechanism behind T(reg) cells expansion in CLL. Neither analysis of the T-cell receptor repertoire nor CD45 isoform expression of T(reg) cells from patients with CLL provided evidence for chronic (tumor) antigenic stimulation as a possible cause for T(reg) cells expansion in CLL. We found evidence however for increased formation of T(reg) cells via CD70 costimulation, because we observed that CD40 ligand activated CLL cells (which might be considered a model of lymph node CLL cells) strongly induced CD70-dependent formation of T(reg) cells. Reverse transcription-multiplex ligation-dependent probe amplification assay expression analysis of 34 apoptosis-regulating genes showed that in comparison with other CD4(+) T-cells, T(reg) cells from both healthy individuals (HD) and patients with CLL had a high expression of pro-apoptotic Noxa and a low expression of anti-apoptotic Bcl-2. Strikingly, Bcl-2 levels of T(reg) cells in patients with CLL were significantly higher than in HD. Finally, the different apoptotic profile resulted in differences at the functional level, because T(reg) cells from patients with CLL were more resistant to drug-induced apoptosis than T(reg) cells from HD. In conclusion, T(reg) cells in CLL may accumulate both by increased formation, facilitated by CD27-CD70 interaction in the lymph node proliferation centres, and decreased sensitivity to apoptosis because of a shifted Noxa-Bcl-2 balance.

Cutting edge: CD95 maintains effector T cell homeostasis in chronic immune activation.

The elimination of activated T cells is important to maintain homeostasis and avoid immunopathology. CD95 (Fas/APO-1) has been identified as a death mediator for activated T cells in vitro but the function of CD95 in death of mature T cells in vivo is still controversial. Here we show that triggering of the costimulatory TNF receptor family member CD27 sensitized T cells for CD95-induced apoptosis. CD95-deficient (lpr/lpr) T cells massively expanded and differentiated into IFN-gamma-secreting effector cells in transgenic mice that constitutively express the CD27 ligand, CD70. Concomitantly, CD95-deficient CD70 transgenic mice became moribund by 4 wk of age with severe liver pathology and bone marrow failure. These findings establish that CD95 is a critical regulator of effector T cell homeostasis in chronic immune activation.