Mass Spectrometry-Based Assessment of M-protein in Peripheral Blood During Maintenance Therapy in Multiple Myeloma.

Mass spectrometry (MS) can detect multiple myeloma-derived monoclonal proteins in peripheral blood (PB) with high sensitivity, potentially serving as a PB assay for measurable residual disease (MRD). This study evaluated the significance of PB MS MRD negativity during post-transplant therapy in patients with newly diagnosed multiple myeloma. Serum samples from 138 patients treated in the phase 3 ATLAS trial of post-transplant maintenance with either carfilzomib, lenalidomide, dexamethasone or lenalidomide alone were analyzed using EXENT MS methodology. We established feasibility of measuring MRD by MS in PB in the post-transplant setting, despite unavailability of pre-treatment calibration samples. There was high agreement between MRD by MS in PB and paired BM MRD results at the 10-5 threshold, assessed by either next generation sequencing (NGS) or multiparameter flow cytometry (MFC) (70% and 67%, respectively). Agreement between PB MS and both BM MRD methods was lowest early after transplant and increased with time. MS negativity was associated with improved progression-free survival (PFS), which in landmark analysis reached statistical significance after 18 cycles post-transplant. Combined PB/BM MRD negativity by MFC or NGS was associated with superior PFS compared to MRD negativity by only one modality. Sustained MS negativity carried similar prognostic performance to sustained BM MRD negativity at the 10-5 threshold. Overall, post-transplant MS assessment was feasible and provided additional prognostic information to BM MRD negativity. Further studies are needed to confirm the role and optimal timing of MS in disease evaluation algorithms. The ATLAS trial is registered at www.clinicaltrials.gov as #NCT02659293.

Real-World Outcome and Prognostic Factors in MDS Patients Treated with Azacitidine-A Retrospective Analysis.

Azacitidine (AZA) is recognized as a vital drug used in the therapy of myelodysplastic syndromes (MDS) due to its beneficial effect on survival and quality of life. Nevertheless, many patients fail to respond to AZA treatment, as prognostic factors still are not identified. The present retrospective analysis included 79 patients with MDS treated with AZA as first-line therapy in a real-life setting. The percentage of patients with good, intermediate, and poor cytogenetics was 46.8%, 11.4%, and 34.2%, respectively. The overall response rate (complete remission [CR], partial remission [PR], and hematological improvement [HI]) was 24%. The CR, PR, and HI rates were 13.9%, 2.5%, and 7.6%, respectively. Stable disease (SD) was documented in 40.5% of patients. The median overall survival (OS) and progression-free survival (PFS) were 17.6 and 14.96 months, respectively. Patients with ORR and SD had a significantly longer median OS (23.8 vs. 5.7 months, p = 0.0005) and PFS (19.8 vs. 3.5 months, p < 0.001) compared to patients who did not respond to AZA. In univariate analysis, only an unfavorable cytogenetic group was a prognostic factor of a lower response rate (p = 0.03). In a multivariate model, older age (p = 0.047), higher IPSS (International Prognostic Scoring System) risk (p = 0.014), and higher IPSS-R cytogenetic risk (p = 0.004) were independent factors of shorter OS. Independent prognostic factors for shorter PFS were age (p = 0.001), IPSS risk (p = 0.02), IPSS cytogenetic risk (p = 0.002), and serum ferritin level (p = 0.008). The safety profile of AZA was predictable and consistent with previous studies. In conclusion, our study confirms the efficacy and safety of AZA in a real-world population and identifies potential biomarkers for response and survival.

Left and right ventricular global longitudinal strain assessment together with biomarker evaluation may have a predictive and prognostic role in patients qualified for hematopoietic stem cell transplantation due to hematopoietic and lymphoid malignancies - a pilot study description.

The hematopoietic stem cell transplantation (HSCT) procedure is considered a cardiovascular burden. This is due to the potentially cardiotoxic cytostatic agents used before and the risks associated with peri-transplant procedures. We designed a pilot study to determine the clinical utility of the new ST2 marker; furthermore, we routinely assessed cardiac parameters in HSCT recipients. Based on previous cardio-oncology experience in lung and prostate cancer, we can confirm the prognostic and predictive value of classic cardiac biomarkers and modern echocardiography parameters such as global longitudinal strain of the left and right ventricle. After conducting this pilot study we can create a predictive and prognostic model for patients undergoing HSCT. This will greatly enrich our clinical practice, especially in treating older people.

Treatment of Double-Refractory Chronic Lymphocytic Leukemia-An Unmet Clinical Need.

Recent years have seen significant improvement in chronic lymphocytic leukemia (CLL) management. Targeting B-cell lymphoma (BCL-2) and Bruton's kinase (BTK) have become the main strategies to restrain CLL activity. These agents are generally well tolerated, but the discontinuation of these therapies happens due to resistance, adverse effects, and Richter's transformation. A growing population of patients who have previously used both BTK inhibitors and BCL2 suffer from the constriction of the following regimens. This review explores the resistance mechanisms for both ibrutinib and venetoclax. Moreover, we present innovative approaches evaluated for treating double-refractory CLL.

Richter transformation - retrospective treatment outcomes analysis in Polish Adult Leukemia Study Group.

Richter transformation (RT) is defined as developing an aggressive lymphoma in 2-10% of patients suffering from chronic lymphocytic leukemia (CLL). So far, no complex analysis of RT demographics and treatment outcomes has been performed in Poland. Thus, the retrospective analysis of 124 patients with RT from Polish hematology centers was designed. Ninety-nine patients with diffuse large B-cell lymphoma (DLBCL-RT) were identified. The median overall survival (OS) for DLBCL-RT was 17.3 months, while for Hodgkin lymphoma (HL-RT)-21.3 months. In multivariate analysis, the independent factors of worse OS for DLBCL-RT were: prior CLL therapy, ECOG stage ≥2, and elevated serum LDH activity. Patients who proceeded to hematopoietic stem cell transplantation (HSCT) achieved better results. The median OS in allogeneic HSCT recipients was not reached, while in autologous HSCT median OS was 51.3 months. In conclusion, our study represents the largest dataset of patients diagnosed with RT in Poland and confirms its dismal prognosis.

Polyclonal immunoglobulin recovery in patients with newly diagnosed myeloma receiving maintenance therapy after autologous haematopoietic stem cell transplantation with either carfilzomib, lenalidomide and dexamethasone or lenalidomide alone: Subanalysis of the randomized phase 3 ATLAS trial.

Previous studies suggest that postautologous stem cell transplant (ASCT) recovery of polyclonal immunoglobulin from immunoparesis in patients with multiple myeloma is a positive prognostic marker. We performed a longitudinal analysis of polyclonal immunoglobulin concentrations and unique B-cell sequences in patients enrolled in the phase 3 ATLAS trial that randomized 180 subjects to either carfilzomib, lenalidomide, dexamethasone (KRd) or lenalidomide (R) maintenance. In the KRd arm, standard-risk patients with minimal residual disease negativity after six cycles de-escalated to R alone after cycle 8. One year from the initiation of maintenance at least partial recovery of polyclonal immunoglobulin was observed in more patients on the R arm (58/66, p < 0.001) and in those who de-escalated from KRd to R (27/38, p < 0.001) compared to the KRd arm (9/36). In patients who switched from KRd to R, the concentrations of uninvolved immunoglobulin and the number of B-cell unique sequences increased over time, approaching values observed in the R arm. There were no differences in progression-free survival between the patients with at least partial immunoglobulin recovery and the remaining population. Our analysis indicates that patients receiving continuous therapy after ASCT experience prolonged immunoparesis, limiting prognostic significance of polyclonal immunoglobulin recovery in this setting.

Clinical efficacy and tolerability of venetoclax plus rituximab in patients with relapsed or refractory chronic lymphocytic leukemia-a real-world analysis of the Polish Adult Leukemia Study Group.

The results of the MURANO trial showed encouraging progression-free survival (PFS) and overall survival (OS) in relapsed/refractory chronic lymphocytic leukemia (RR-CLL) patients treated with venetoclax-rituximab (VEN-R). A retrospective analysis was performed to evaluate the efficacy and safety of VEN-R within the Polish Adult Leukemia Study Group (PALG) centers. The study group included 117 patients with RR-CLL (with early relapse after immunochemotherapy or bearing TP53 aberrations) treated with VEN-R in 2019-2023 outside clinical trials. Patients were treated with a median of 2 (range 1-9) previous lines of therapy. Twenty-two participants were previously treated with BTKi (18.8% out of 117). The median follow-up was 20.3 months (range 0.27-39.1). The overall response rate (ORR) was 95.3% in the group of patients in whom a response to treatment was assessed and 86.3% for all patients. Twenty patients (17.1% out of 117) achieved a complete response (CR), 81 (69.2%) achieved a partial response (PR), and in 5 patients (4.3%), disease progression was noted (assessed as the best response during treatment). The median PFS in the whole cohort was 36.97 (95% CI 24.5, not reached) months, and the median OS was not reached (95% CI 27.03, not reached). Thirty-six patients died during the follow-up, 10 (8.5%; 27.8% of deaths) due to COVID-19 infection. All grade neutropenia (n = 87/117, 74.4%; grade 3 or higher n = 67/117, 57.3%) was the most common treatment adverse event. Forty-five patients (38.5%) remained on treatment, and twenty-two (18.8%) completed 24 months of therapy, while it was discontinued in fifty cases (42.7%). In this real-world setting of early access in very high-risk RR-CLL patients, the VEN-R regimen was associated with shorter median PFS compared with the results of the MURANO trial. This outcome, however, could be attributed to patients' exposure to SARS-CoV-2 infection and the aggressive course of the disease as very high-risk patients, after multiple lines of prior therapies, were included in the Polish Ministry of Health reimbursement program.

Molnupiravir is effective in patients with haematological malignancies.

Patients with hematologic malignancies are particularly vulnerable to severe infectious complications. SARS-CoV-2 infection is associated with a high risk of severe course and death in this patient population. In addition, immune deficits associated with both the blood cancer and the treatment used make vaccination against SARS-CoV-2 less effective than in immunocompetent individuals. Molnupiravir is one of the first oral antiviral drugs to demonstrate a significant benefit in reducing hospitalisation and death in COVID-19 in the general population. In this context, 175 haematology patients with diagnosed COVID-19, and treated with MOL between January and April 2022, came under our scrutiny with a view to defining their clinical characteristics and outcomes. The most common underlying conditions were lymphomas (45%), multiple myelomas (21%) and acute leukaemias or myelodysplastic syndrome (35%). Of all, 77% of the patients were vaccinated, and half of them received a booster. At 28 days after the breakthrough COVID-19 diagnosis, 35 (20%) subjects required hospital admission. Out of those patients, seven (4%) died during the follow-up due to the progression of COVID. Our results corroborate what has been established to date with regard to the positive clinical and safety outcomes of MOL in haematology patients with mild or moderate COVID-19.

Carfilzomib, lenalidomide, and dexamethasone or lenalidomide alone as maintenance therapy after autologous stem-cell transplantation in patients with multiple myeloma (ATLAS): interim analysis of a randomised, open-label, phase 3 trial.

BACKGROUND: Lenalidomide is a cornerstone of maintenance therapy in patients with newly diagnosed multiple myeloma after autologous stem-cell transplantation. We aimed to compare the efficacy and safety of maintenance therapy with carfilzomib, lenalidomide, and dexamethasone versus lenalidomide alone in this patient population. METHODS: This study is an interim analysis of ATLAS, which is an investigator-initiated, multicentre, open-label, randomised, phase 3 trial in 12 academic and clinical centres in the USA and Poland. Participants were aged 18 years or older with newly diagnosed multiple myeloma, completed any type of induction and had stable disease or better, autologous stem-cell transplantation within 100 days, initiated induction 12 months before enrolment, and an Eastern Cooperative Oncology Group performance status of 0 or 1. Patients were randomly assigned (1:1) using permuted blocks of sizes 4 and 6 and a web-based system to receive up to 36 cycles of carfilzomib, lenalidomide, and dexamethasone (28-day cycles of carfilzomib 20 mg/m2 administered intravenously in cycle one on days 1 and 2 then 36 mg/m2 on days 1, 2, 8, 9, 15, and 16 in cycles one to four and 36 mg/m2 on days 1, 2, 15, and 16 from cycle five up to 36 [per protocol]; lenalidomide 25 mg administered orally on days 1-21; and dexamethasone 20 mg administered orally on days 1, 8, 15, and 22) or lenalidomide alone (10 mg administered orally for the first three cycles and then at the best tolerated dose [≤15 mg for 28 days in 28-day cycles]) until disease progression or unacceptable toxicity as maintenance therapy. After 36 cycles, patients in both treatment groups received lenalidomide maintenance. Randomisation was stratified by response to previous treatment, cytogenetic risk factors, and country. Investigators and patients were not masked to treatment allocation. Patients in the carfilzomib, lenalidomide, and dexamethasone group with no detectable minimal residual disease after cycle six (as per International Myeloma Working Group criteria) and standard-risk cytogenetics were switched to lenalidomide maintenance as of cycle nine. The primary endpoint was progression-free survival in the intention-to-treat population (defined as all randomly assigned patients). Safety was analysed in all randomly assigned patients who received at least one dose of study treatment. This unplanned interim analysis was triggered by the occurrence of 59 (61%) of the expected 96 events for the primary analysis and the results are considered preliminary. This trial is registered with ClinicalTrials.gov, NCT02659293 (active, not recruiting) and EudraCT, 2015-002380-42. FINDINGS: Between June 10, 2016, and Oct 21, 2020, 180 patients were randomly assigned to receive either carfilzomib, lenalidomide, and dexamethasone (n=93) or lenalidomide alone (n=87; intention-to-treat population). The median age of patients was 59·0 years (IQR 49·0-63·0); 84 (47%) patients were female and 96 (53%) were male. With a median follow-up of 33·8 months (IQR 20·9-42·9), median progression-free survival was 59·1 months (95% CI 54·8-not estimable) in the carfilzomib, lenalidomide, and dexamethasone group versus 41·4 months (33·2-65·4) in the lenalidomide group (hazard ratio 0·51 [95% CI 0·31-0·86]; p=0·012). The most common grade 3 and 4 adverse events were neutropenia (44 [48%] in the carfilzomib, lenalidomide, and dexamethasone group vs 52 [60%] in the lenalidomide group), thrombocytopenia (12 [13%] vs six [7%]), and lower respiratory tract infections (seven [8%] vs one [1%]). Serious adverse events were reported in 28 (30%) patients in the carfilzomib, lenalidomide, and dexamethasone group and 19 (22%) in the lenalidomide group. One treatment-related adverse event led to death (respiratory failure due to severe pneumonia) in the carfilzomib, lenalidomide, and dexamethasone group. INTERPRETATION: This interim analysis provides support for considering carfilzomib, lenalidomide, and dexamethasone therapy in patients with newly diagnosed multiple myeloma who completed any induction regimen followed by autologous stem-cell transplantation, which requires confirmation after longer follow-up of this ongoing phase 3 trial. FUNDING: Amgen and Celgene (Bristol Myers Squibb).

Response to anti-SARS-CoV-2 mRNA vaccines in multiple myeloma and chronic lymphocytic leukemia patients.

Multiple myeloma (MM) and chronic lymphocytic leukemia (CLL) patients have increased morbidity and mortality rates of COVID-19 due to immunosuppression associated with the disease and ongoing therapy. The same immune impairment accompanying CLL and MM also affects suboptimal vaccine response. The study assessed the effectiveness of the humoral and T cell-mediated immunity following mRNA COVID-19 vaccination (using either BNT162b2 or mRNA-1273) in short-term (2-5 weeks after second dose) and long-term follow-up (12 weeks after vaccination). Between March and August 2021, blood samples were obtained from 62 CLL and 60 MM patients from eight different hematology departments in Poland. Total anti-RBD antibodies were detected in 37% MM patients before vaccination, increased to 91% and 94% in short- and long-term follow-up, respectively. In CLL, serological responses were detectable in 21% of patients before vaccination and increased to 45% in the short-term and 71% in long-term observation. We detected a tendency to higher frequencies of specific CD8+ T cells against SARS-CoV-2 after vaccination compared to samples before vaccination in MM patients and no changes in frequencies of specific T cells in CLL patients. Our study provides novel insights into mRNA vaccination efficacy in immunocompromised MM and CLL patients, and our findings highlight that specific CD8+ T cells against SARS-CoV-2 might be induced by vaccination but do not correlate positively with serological responses.

Extracellular Vesicles in Multiple Myeloma-Cracking the Code to a Better Understanding of the Disease.

Multiple myeloma (MM) is a plasma cell-derived malignancy that stands for around 1.5% of newly discovered cancer cases. Despite constantly improving treatment methods, the disease is incurable with over 13,000 deaths in the US and over 30,000 in Europe. Recent studies suggest that extracellular vesicles (EVs) might play a significant role in the pathogenesis and evolution of MM. Further investigation of their role could prove to be beneficial in establishing new therapies and hence, improve the prognosis of MM patients. What is more, EVs might serve as novel markers in diagnosing and monitoring the disease. Great advancements concerning the position of EVs in the pathophysiology of MM have recently been shown in research and in this review, we would like to delve into the still expanding state of knowledge.

Tracking Clonal Evolution of Multiple Myeloma Using Targeted Next-Generation DNA Sequencing.

Clonal evolution drives treatment failure in multiple myeloma (MM). Here, we used a custom 372-gene panel to track genetic changes occurring during MM progression at different stages of the disease. A tumor-only targeted next-generation DNA sequencing was performed on 69 samples sequentially collected from 30 MM patients. The MAPK/ERK pathway was mostly affected with KRAS mutated in 47% of patients. Acquisition and loss of mutations were observed in 63% and 37% of patients, respectively. Four different patterns of mutation evolution were found: branching-, mutation acquisition-, mutation loss- and a stable mutational pathway. Better response to anti-myeloma therapy was more frequently observed in patients who followed the mutation loss-compared to the mutation acquisition pathway. More than two-thirds of patients had druggable genes mutated (including cases of heavily pre-treated disease). Only 7% of patients had a stable copy number variants profile. Consequently, a redistribution in stages according to R-ISS between the first and paired samples (R-ISS″) was seen. The higher the R-ISS″, the higher the risk of MM progression and death. We provided new insights into the genetics of MM evolution, especially in heavily pre-treated patients. Additionally, we confirmed that redefining R-ISS at MM relapse is of high clinical value.

Immunophenotypic Characteristics of Bone Marrow Microenvironment Cellular Composition at the Biochemical Progression of Multiple Myeloma.

Multiple myeloma (MM) relapses are inevitable in the majority of patients, and in addition to genetic changes in the MM clone, the immune profile of the bone marrow (BM) plays a key role in this process. Biochemical progression or relapse (BR) precedes clinical relapse in a significant proportion of patients with MM. In the present study, we used flow cytometry to assess the cellular composition of the BM microenvironment in MM patients with confirmed BR. Fifteen distinct cells subsets in the BM were evaluated with the panel of antibodies used routinely for MRD monitoring in MM in 52 patients with MM (MRD-negative n = 20, BR n = 20, and clinically relapsed MM, RMM n = 12). The median percentage of MM cells detected in BR patients was 0.90% versus not detectable in MRD-negative patients and of 3.0% in RMM cohort. Compared to the MRD-negative group, BR status was associated with an increase in the percentage of lymphoid subpopulations, including memory B cells (p = 0.003), CD27+T cells (p = 0.002), and NK/NKT cells (p < 0.001). Moreover, a decrease in B-cell precursors (p < 0.001) and neutrophils (p = 0.006) was observed. There were no significant differences in the composition of the BM cell subpopulations between the BR and RMM groups. Our results indicate the involvement of B-, T-, and NK cells in the process of losing immune surveillance over the MM clone that leads to relapse. It can be speculated that similar studies of a larger cohort of BR patients can potentially identify a group of patients for which an early treatment intervention would be beneficial.

PI3K Inhibitors for the Treatment of Chronic Lymphocytic Leukemia: Current Status and Future Perspectives.

Phosphoinositide 3-kinases (PI3Ks) signaling regulates key cellular processes, such as growth, survival and apoptosis. Among the three classes of PI3K, class I is the most important for the development, differentiation and activation of B and T cells. Four isoforms are distinguished within class I (PI3Kα, PI3Kß, PI3Kδ and PI3Kγ). PI3Kδ expression is limited mainly to the B cells and their precursors, and blocking PI3K has been found to promote apoptosis of chronic lymphocytic leukemia (CLL) cells. Idelalisib, a selective PI3Kδ inhibitor, was the first-in-class PI3Ki introduced into CLL treatment. It showed efficacy in patients with del(17p)/TP53 mutation, unmutated IGHV status and refractory/relapsed disease. However, its side effects, such as autoimmune-mediated pneumonitis and colitis, infections and skin changes, limited its widespread use. The dual PI3Kδ/γ inhibitor duvelisib is approved for use in CLL patients but with similar toxicities to idelalisib. Umbralisib, a highly selective inhibitor of PI3Kδ and casein kinase-1ε (CK1ε), was found to be efficient and safe in monotherapy and in combination regimens in phase 3 trials in patients with CLL. Novel PI3Kis are under evaluation in early phase clinical trials. In this paper we present the mechanism of action, efficacy and toxicities of PI3Ki approved in the treatment of CLL and developed in clinical trials.

Outcome of SARS-CoV-2-Infected Polish Patients with Chronic Lymphocytic Leukemia.

BACKGROUND: The severe acute respiratory syndrome coronavirus (SARS-CoV-2) has become the cause of a worldwide pandemic, and its clinical infection course in patients with hematological malignancies may be severe. METHODS: We performed a retrospective study on 188 chronic lymphocytic leukemia patients (CLL) with COVID-19 infection. RESULTS: At the time of infection 51 patients (27.1%) were treated with Bruton tyrosine kinase inhibitor (BTKi), 46 (24.5%) with anti-CD20 antibodies while 37 patients (19.7%) received venetoclax. In total, 111 patients (59.0%) required hospitalization and 50 patients (26.5%) died due to COVID-19. Patients with poor performance status (ECOG >1; p = 0.02), advanced age (>65 years; p = 0.04), low hemoglobin concentration (≤10 g/dl; p = 0.0001), low platelets (<100 × 109/L; p = 0.003), and elevated lactate dehydrogenase level (LDH; p = 0.014) had an increased risk of death due to COVID-19. Neither CLL treatment status (treatment naïve vs. treated) nor the type of CLL-directed treatment had impact on the SARS-CoV-2 related risk of death. The multivariate survival analysis showed that advanced age (p = 0.009) and low platelet count (p = 0.0001) were associated with significantly shorter patients' overall survival. CONCLUSIONS: SARS-CoV-2 infection in CLL patients is associated with poor outcome regardless of administered CLL-directed treatment.

Totally extraperitoneal inguinal hernia repair in patients with hemophilia and von Willebrand disease. Prospective controlled study.

INTRODUCTION: Laparoscopic surgery is associated with several advantages. Surgical procedures in hemophilia or von Willebrand patients without replacement therapy (RT) to correct clotting factor deficiency may result in serious, life-threatening hemorrhagic episodes. Clotting factor concentrates improve hemostatic control but bleeding risk in major invasive procedures remains high. AIM: Evaluation of totally extraperitoneal inguinal hernia repair (TEP-IHR) in patients with congenital hemorrhagic disorders (H) and comparison with results for non-hemophiliacs (NH) with regard to bleeding, postoperative pain, hernia recurrence, surgery time, demand for painkillers, hospital stay and recovery time. MATERIAL AND METHODS: The prospective controlled trial included 67 consecutive male patients scheduled for TEP-IHR between January 2010 and December 2018. Surgery was performed in groups H (n = 22) and NH (n = 45). Full study inclusion criteria were met by 65 patients (22 and 43 in H and NH groups respectively). Follow-up was carried out on the 1st, 2nd, and 7th day and in the 1st and 3rd month postoperatively. RESULTS: TEP-IHR was successful for all patients. No life-threatening bleeding occurred and no patient required red blood cell transfusions or reoperation. No hernia recurrence was reported. No statistically significant differences were observed between the groups with regard to surgery duration, postoperative hematoma frequency and demand for painkillers. In the H group, pain intensity was significantly higher during the first postoperative month and hospitalization and recovery were significantly longer. CONCLUSIONS: TEP-IHR in hemophiliacs with RT is feasible and as effective for preventing hernia recurrence as in NH-patients. In hemophiliacs risk of bleeding complications and demand for painkillers are comparable to non-hemophiliacs although pain is more intense.

Harmonization of Flow Cytometric Minimal Residual Disease Assessment in Multiple Myeloma in Centers of Polish Myeloma Consortium.

Minimal residual disease (MRD) status is now considered as one of the most relevant prognostic factors in multiple myeloma (MM) while MRD negativity became an important endpoint in clinical trials. Here, we report the results of the first study evaluating the reproducibility of high-sensitivity flow cytometry MM MRD assessment in four laboratories in Poland. EuroFlow protocols for instrument setting standardization and sample preparation in MM MRD assessment were implemented in each laboratory. In the inter-laboratory reproducibility study, 12 bone marrow samples from MM patients were distributed and processed in participant laboratories. In the inter-operator concordance study, 13 raw data files from MM MRD measurements were analyzed by five independent operators. The inter-laboratory study showed high 95% overall concordance of results among laboratories. In the inter-operator study, 89% of MRD results reported were concordant, and the highest immunophenotype interpretation differences with regard to expression of CD27, CD45, CD81 were noticed. We confirmed the applicability and feasibility of the EuroFlow protocol as a highly sensitive method of MRD evaluation in MM. Results of our inter-center comparison study demonstrate that the standardization of MM MRD assessment protocols is highly desirable to improve quality and comparability of results within and between different clinical trials.

Inhibition of PIM Kinases in DLBCL Targets MYC Transcriptional Program and Augments the Efficacy of Anti-CD20 Antibodies.

The family of PIM serine/threonine kinases includes three highly conserved oncogenes, PIM1, PIM2, and PIM3, which regulate multiple prosurvival pathways and cooperate with other oncogenes such as MYC. Recent genomic CRISPR-Cas9 screens further highlighted oncogenic functions of PIMs in diffuse large B-cell lymphoma (DLBCL) cells, justifying the development of small-molecule PIM inhibitors and therapeutic targeting of PIM kinases in lymphomas. However, detailed consequences of PIM inhibition in DLBCL remain undefined. Using chemical and genetic PIM blockade, we comprehensively characterized PIM kinase-associated prosurvival functions in DLBCL and the mechanisms of PIM inhibition-induced toxicity. Treatment of DLBCL cells with SEL24/MEN1703, a pan-PIM inhibitor in clinical development, decreased BAD phosphorylation and cap-dependent protein translation, reduced MCL1 expression, and induced apoptosis. PIM kinases were tightly coexpressed with MYC in diagnostic DLBCL biopsies, and PIM inhibition in cell lines and patient-derived primary lymphoma cells decreased MYC levels as well as expression of multiple MYC-dependent genes, including PLK1. Chemical and genetic PIM inhibition upregulated surface CD20 levels in an MYC-dependent fashion. Consistently, MEN1703 and other clinically available pan-PIM inhibitors synergized with the anti-CD20 monoclonal antibody rituximab in vitro, increasing complement-dependent cytotoxicity and antibody-mediated phagocytosis. Combined treatment with PIM inhibitor and rituximab suppressed tumor growth in lymphoma xenografts more efficiently than either drug alone. Taken together, these results show that targeting PIM in DLBCL exhibits pleiotropic effects that combine direct cytotoxicity with potentiated susceptibility to anti-CD20 antibodies, justifying further clinical development of such combinatorial strategies. SIGNIFICANCE: These findings demonstrate that inhibition of PIM induces DLBCL cell death via MYC-dependent and -independent mechanisms and enhances the therapeutic response to anti-CD20 antibodies by increasing CD20 expression.