Minimal Residual Disease Evaluation Research Articles

Multicenter Open Label Phase 2 Study of Quadruplet-Based Regimen Iskpd (isatuximab plus pomalidomide and dexamethasone with carfilzomib) in Early Relapsed or Refractory Multiple Myeloma - IFM2018-03

Background. RRMM (relapsed or refractory multiple myeloma) is associated to shortened OS (survival) with subsequent relapses and needs optimized treatment approaches. The current treatment paradigm is based on triplet-based association of antiCD38 immunotherapy (antiCD38 IT) with either Imids (Pomalidomide) and dexamethasone or proteasome inhibitors (PI) such as Carfilzomib and dexamethasone. However, quadruplet-based regimens (antiCD38 immunotherapy +Imids +PI +dexamethasone) have transformed the treatment landscape in the upfront setting, improving MRD (minimal residual disease) and survival. We hypothesized that a quadruplet-based regimens (antiCD38 immunotherapy +Imids +PI +dexamethasone) would further improved MRD and survival in early RRMM. We describe a phase II multicentric, open-label study, of isatuximab, pomalidomide and dexamethasone plus carfilzomib (IsKPd/ IFM2018-03, NCT04287855) for patients with early RRMM. Study design and Methods. Approximately 90 patients will receive the association of isatuximab, pomalidomide and dexamethasone with carfilzomib (IsKPd), and the study has fully enrolled 82 patients as of January 2023. Eligible patients are adults aged ≥18 years old with RRMM previously treated with 1 or 2 lines of therapy, including lenalidomide, prior to the study entry. Patients were excluded if they were refractory to any anti-CD38 monoclonal antibody or to carfilzomib, or if they were previously exposed to pomalidomide. Isatuximab will be given by IV route at 10 mg/kg on days 1, 8, 15, and 22 of cycle 1, on days 1 and 15 from cycle 2 to 12 and on day 1 only from cycle 13, 28-day cycles. Carfilzomib will be given by IV route at 20/27 mg/m² on days 1-2, 8-9, 15-16 during cycle 1, at 56mg/m² on days 1, 8, 15 from cycle 2 to 13 and at 56mg/m² on days 1 and 15 after cycle 13. Pomalidomide will be administered by oral route at 3 mg daily on days 1 to 21 in cycle 1 and at 4 mg daily from cycle 12. Dexamethasone will be given by oral route at 40/20 mg daily on days 1, 8, 15 and 22. The primary objective is to evaluate the MRD rate at 10-5 in patients with RRMM treated with IsKPd. Patients will pursue Isa-KPd until progression or unacceptable toxicity. Key secondary objectives include the survival analysis (OS, PFS, EFS, TTNT), response rates and duration of response and evaluation of the safety profile. The study is expected to read out in January 2024 with sustained MRD reported.

Tailor: Interventional Study Evaluating Physician's Choice of Ibrutinib Monotherapy or Ibrutinib-Venetoclax Combination Using Dose Modifications and Alternate Dosing Approaches in Patients with Untreated Chronic Lymphocytic Leukemia

Background: Ibrutinib is a first-in-class Bruton's tyrosine kinase inhibitor (BTKi) that has changed the treatment paradigm for patients with chronic lymphocytic leukemia (CLL) with durable responses and improved overall survival (OS). In the pivotal Phase 3 GLOW and Phase 2 CAPTIVATE trials, fixed-duration combination of ibrutinib-venetoclax (I+V) resulted in deep and sustained clinical responses, and a broadly manageable safety profile in patients with CLL. Several factors including genetic features, disease status, comorbidities, patient preferences, and safety profiles contribute to selection of the optimal therapeutic option for patients with CLL in the first-line setting. Adverse events (AEs), such as atrial fibrillation, bleeding, and hypertension, have been seen with the BTKi therapeutic class.Long-term clinical and real-world experience with ibrutinib has led to specific guidance regarding AE management, which has been included in the updated ibrutinib prescribing information (US PI, May 2022; EU SmPC, April 2023). Retrospective evidence, including post-hoc analyses of clinical trial data, demonstrates that dose reduction of ibrutinib mitigates recurrence or worsening of AEs while preserving efficacy. Thus, these findings together support the rationale to prospectively evaluate the impact of regimen and dosing flexibility of ibrutinib in patients with untreated CLL. Aim: The key objective of the TAILOR study (NCT05963074) is to assess the efficacy and safety of I+V and ibrutinib monotherapy regimens with both a proactive and reactive dose adjustment in patients with untreated CLL. Methods: TAILOR is a phase 2, two-arm, four-cohort interventional study designed to provide physicians the choice of ibrutinib monotherapy or I+V combination therapy for previously untreated patients with CLL and prospectively evaluate proactive and reactive dose adjustment approaches. Eligible patients will have previously untreated active CLL, needing therapy as per iwCLL 2018 criteria. Key exclusion criteria include significant active or history of cardiovascular disease, uncontrolled hypertension, and ECOG performance status > 2. Patients will be randomized after selection of regimen: I+V fixed-duration regimen (2 cohorts, 80 patients in each cohort) or ibrutinib monotherapy (2 cohorts, 80 patients in each cohort), as per physician's choice. Patients in the I+V arm will receive ibrutinib 420 mg QD as lead-in for 3 cycles plus 12 cycles of either ibrutinib 420 mg QD (Cohort 1a) or 280 mg QD (Cohort 1b) in combination with venetoclax, which will be initiated in cycle 4 with dose ramp-up per label over 5 weeks (20, 50, 100, 200, and 400 mg/day) and continued at 400 mg/day dose from cycle 5 onward. In addition, patients with deletion 17p and/or mutated TP53 will receive optional ibrutinib maintenance. Patients in the ibrutinib monotherapy arm will receive ibrutinib 420 mg QD (Cohort 2a) or 420 mg QD for 3 cycles, then 280 mg QD (Cohort 2b) until progressive disease or unacceptable toxicity ( Figure). All cohorts will follow the dose modification guidance as per protocol based on the US PI/ EU SmPC. The primary endpoint is best overall response rate as assessed by investigators and compared with historic controls. Secondary endpoints include: complete response rate, duration of response, PFS, and OS; undetectable minimal residual disease rate (I+V cohorts only); safety (AEs, discontinuation due to AEs, adherence rates); and patient reported outcomes. The study is currently recruiting patients.

Final Analysis of a Phase 2 Trial of Daratumumab, Carfilzomib, Lenalidomide, and Dexamethasone in Newly Diagnosed Multiple Myeloma (NDMM) without Autologous Stem Cell Transplantation (ASCT)

Introduction: A previous trial showed that Dara-KRd for 8 cycles without ASCT led to a minimal residual disease (MRD) negativity rate of 71% at 10 -5 in NDMM (Landgren et al. JAMA Oncology 2021). MRD-adapted Dara-KRd with ASCT led to an MRD(-) rate of 71% at 10 -6 with a 3-year progression-free survival (PFS) of 88%, 79%, and 50% in pts with 0, 1 or 2+ high-risk cytogenetic abnormalities (HRCA), respectively (Costa et al. EHA 2022). In this phase 2 study, we evaluated the safety and efficacy of 24 cycles of Dara-KRd without ASCT in pts with NDMM. Methods: Pts with NDMM with up to 1 cycle of prior therapy were enrolled regardless of ASCT eligibility. Pts received Dara-KRd for planned 24 cycles: daratumumab 16 mg/kg IV weekly for cycles (C) 1 & 2, q2weeks for C3-8, then q4weeks for C9-24; carfilzomib 20/36 mg/m 2 on days 1, 2, 8, 9, 15, 16 for C1-8, then 36 mg/m 2 on days 1, 2, 15, 16 for C9-24; lenalidomide 25 mg PO days 1-21 of a 28 day cycle for 24 cycles; dexamethasone 40 mg PO weekly (20 mg if age > 75) for C1-9, and 20 mg PO weekly for C9-24. Pts had the option to harvest stem cells (SC) to permit ASCT in the future. MRD testing was performed by NGS (clonoSEQ, Adaptive Biotechnologies) with sensitivity <10 -6 at the end of cycles 8 (C8), C12, and C24. Mass spectrometry (MS) of peripheral blood samples were also performed using MALDI and liquid-chromatography (LCMS) (The Binding Site Group). The primary endpoint was the rate of stringent CR and/or MRD(-) <10 -5 at the end of C8; the hypothesis was that >50% would meet the primary endpoint with Dara-KRd compared to historical 30% with KRd (85% power, one-sided alpha=0.10). Results: 42 pts enrolled from March 2019-January 2022. Median age was 58 years (range 39-79). 13 (31%) were Black and 5 (12%) were Hispanic. HRCA (t(4;14), t(14;16), t(14;20), +1q, del17p) were present in 24/42 (57%); 10 (24%) had 2+ HRCA. 34 pts (81%) underwent SC collection, all with plerixafor (median yield 8.91x10 6 CD34+/kg). 40 pts (95%) were evaluable for the primary endpoint at C8. Two pts withdrew before C8 for reasons unrelated to treatment. There were 32 (80%) MRD-evaluable pts at C8. The sCR and/or MRD(-) rate (<10 -5) was 30/40 (75%, 95% CI 61%-89%). The C8 10 -5 MRD(-) rate was 20/32 (63%) and at 10 -6 it was 12/32 (38%). Responses deepened over time; 1/12 (8%) and 6/20 (30%) pts converted from MRD(+) at C8 to MRD(-) at later timepoints at 10 -5 and 10 -6 thresholds, respectively, for a best MRD(-) rate of 21/32 (66%) at 10 -5 and 18/32 (56%) at 10 -6 . Sustained 10 -5 MRD(-) >12 months was achieved in 11 (26%) pts; 6 pts were <1 year from first MRD(-) result. Overall response rate at C8 was 38/40 (95%) with 27 (68%) sCR, 38 (95%) VGPR+, and 2 PD. Of the 39 pts with trackable mass spectra in the peripheral blood, the MALDI(-) rate was 22/39 (56%) after C8 and 24/39 (62%) as best response. The LCMS(-) rate was 7/39 (18%) after C8 and 12/39 (31%) as best response. Median follow-up was 27 months. 21 pts (50%) completed all 24 cycles, and 11 (26%) remain on protocol. 7 pts (17%) had disease progression (6 on protocol), including 4 pts who reached the primary endpoint at C8. 4 pts (10%) discontinued protocol therapy early (additional 2 pts due to nonadherence). 1 pt received ASCT after discontinuing while in response. 2 deaths occurred, both early in treatment and due to primary refractory disease. The 3-year PFS was 85%: 100% for standard-risk disease, 92% for 1 HRCA, and 60% for 2+ HRCA. Of the 7 pts with progression, 6 had at least one of: extramedullary disease (4), 2+ HRCA (4), or circulating plasma cells (1). Neither NGS nor mass spectrometry status at C8 were associated with PFS differences using the landmark method. The 3-year OS was 95%. All-grade/grade 3+ (G3) neutropenia occurred in 26%/21%, anemia in 59%/2%, and thrombocytopenia in 64%/26%. Notable nonhematologic adverse events were hyperglycemia (all 76%/ G3+ 7%), diarrhea (71%/5%), hypertension (57%/17%), and neuropathy (40%/0%). COVID infections occurred in 38% (2% G3) and upper respiratory infections in 45% (0% G3+). There was one case of thrombotic microangiopathy leading to discontinuation of carfilzomib. G3 atrial fibrillation and heart failure each occurred in 1 pt. Conclusions: Extended frontline Dara-KRd for NDMM without ASCT induced high rates of sCR and/or MRD(-) within 8 cycles, meeting the primary endpoint. The rate and depth of MRD(-) improved beyond C8. This ASCT-free approach led to lower PFS for pts with 2+ HRCA, as also seen with ASCT, but excellent PFS in those with standard-risk disease and 1 HRCA.

Early-Stage Follicular Lymphoma: Learnings from the Final Analysis of the Multicenter Phase II FIL (Fondazione Italiana Linfomi) “Miro” Trial, Combining Local Radiotherapy and MRD-Driven Immunotherapy

Introduction. Early-stage follicular lymphoma (FL) is usually managed with involved field radiotherapy (IFRT), allowing a complete and long-lasting eradication of the disease in 40-50% of patients (pts). The aim of this multicenter phase II prospective study was to evaluate if a minimal residual disease (MRD)-driven immunotherapy consolidation after IFRT can improve the outcome of pts unlikely to be cured by IFRT only, and to assess the therapeutic effect of IFRT and anti-CD20 consolidation by MRD evaluation. Methods. One hundred and ten pts with stage I/II FL were enrolled; 106 were evaluable and treated with 24 Gy IFRT. Peripheral blood (PB) and bone marrow (BM) samples were centralized to the FIL (Fondazione Italiani Linfomi) MRD Network of EuroMRD-certified laboratories. In pts BCL2::IGH+ at baseline by both nested PCR (NEST) and RQ-PCR (RQ) in the BM and/or (a/o) PB, MRD was analyzed after IFRT and every 6 months over a 3-year period. Pts who were MRD+ by both NEST and RQ in the BM a/o PB after IFRT or who became MRD+ during the follow-up were treated with 8 weekly doses of the anti-CD20 monoclonal antibody ofatumumab (OFA). The primary objective of the study was to define the efficacy of immunotherapy in obtaining a negative MRD. Results. Of the 106 evaluable pts, 50 were males (47%). Median age was 55.5 years (29-83). The FLIPI score was 0 in 60% of pts, 1 in 34%, 2 in 6%; 69% of pts had inguinal site involvement, significantly more frequent in young patients. At baseline, 30.5% of pts had a BCL2::IGH rearrangement (30 MBR, 1 MBR and mcr, 1 mcr) in the BM a/o PB; the concordance between compartments was 87%. BCL2::IGH+ and BCL2::IGH- pts were not significantly different, except for a younger age (p 0.009) and a more frequent FLIPI 0 (p 0.052) among marker negative cases. All but 1 pt achieved a clinical response after IFRT; 1 pt died soon after IFRT of unrelated causes. MRD evaluation after IFRT revealed the persistence of BCL2::IGH+ cells in the PB a/o BM in 60% of pts. MRD+ pts, either after IFRT (n=18) or in case of conversion to MRD+ during the follow-up (n=8), received OFA, obtaining a conversion to MRD- in 23/25 evaluable pts (92%, CI 74-99%), significantly superior to the expected 50%. After a median follow-up of 46.3 months (m) (range 11-66), of the 23 pts who achieved a MRD- with OFA, 5 returned MRD+ (4 underwent OFA re-treatment, achieving a second MRD-, 1 relapsed as a transformation), 4 relapsed being MRD-, 14 remain in complete remission and MRD-, with a duration of molecular response at the last molecular assessment of 30 months (range 6-36). Overall, a clinical relapse was observed in 29 pts submitted to IFRT and 1 patient progressed soon after IFRT. A confirmed histologic transformation to DLBCL was observed in 5 of these patients. Among the 73 “marker negative” patients, 20 relapsed (27.4%) over time, whilst among the 32 BCL2::IGH+ at baseline 9 (28.1%) were resistant or relapsed (p=0.939). The administration of OFA was associated to a significantly reduced risk of POD24 (p= 0.035). Overall, the 24-m and 36-m overall survival (OS) were 100% and 98.9%, respectively; the 24-m and 36-m PFS were 83.7% and 77.4%, respectively. PFS was not different according to the presence or absence of BCL2::IGH at enrollment (p=0.820). PFS was significantly different according to the FLIPI score (p=0.041), but not different according to gender (p=0.696), stage I-II (p=0.122), histological grade (p=0.212), inguinal nodal site vs others (p=0.492). The Kaplan Meier landmark analysis, stratified by MRD, at m+6 (p=0.228), m+12 (p=0.003), m+18 (p=0.0002), m+24 (p=0.004) showed that PFS significantly improved from m+12 onwards when a negative MRD was present (Figure 1). Conclusions. IFRT alone is often insufficient to eradicate FL, inducing a MRD- status only in 40% of pts, long-lasting only in a third of them. An immunotherapy consolidation with OFA after IFRT in MRD+ pts was capable of increasing the molecular responses to 92%, allowing to achieve the primary objective of the study, though this effect was not always persistent. The achievement of a molecular remission correlated significantly with a reduction in the incidence of relapse over time, although this strategy was applicable only to 30% BCL2::IGH+ PET/CT staged FL pts. A consolidation strategy with more effective agent should be advisable. With these limits, a clinical advantage of the MRD-driven treatment strategy is suggested, although not largely applicable.

Phase 1 Study of CART-Ddbcma for the Treatment of Patients with Relapsed and/or Refractory Multiple Myeloma: Results from at Least 1-Year Follow-up in All Patients

Introduction: CART-ddBCMA, an autologous anti-B-cell maturation antigen (BCMA) chimeric antigen receptor (CAR) T-cell therapy with a unique, synthetic binding domain, is being studied in a first-in-human clinical trial in patients (pts.) with relapsed &/or refractory multiple myeloma (RRMM). One-year or more follow-up clinical data from all patients are presented in this report. Methods: Details of study design have been previously reported (Frigault et al Blood Adv 2023). Briefly, pts with RRMM who have received ≥3 prior lines of therapy were enrolled & received a single infusion of CART-ddBCMA following lymphodepletion chemotherapy (fludarabine: 30 mg/m 2/d & cyclophosphamide: 300 mg/m 2/d daily for 3 days). Two dose levels (DL1 & DL2 respectively) of 100 & 300 (±20%) ×10 6 CAR+ cells were evaluated. The primary endpoints included incidence of adverse events (AEs) & dose-limiting toxicities (DLTs). Additional endpoints included quality & duration of clinical response assessed according to the IMWG Uniform Response Criteria for MM, evaluation of minimal residual disease (MRD), progression-free (PFS) & overall survival (OS). Correlative analyses related to CART-ddBCMA expansion, characterization, patient & disease-related features were also evaluated. Results: As of June 2, 2023, 40 pts; median age 66 years (range: 44-76) were enrolled; 38 received CART-ddBCMA (32, DL1; 6, DL2) & 38 were evaluable for initial safety & clinical response. Two pts who were not dosed had cell product manufactured but were not eligible for cell infusion due to medical complications. Pts had a median of 4 (range: 3-16) prior lines of therapy. All infused pts (100%) were triple-refractory, & 26 (68%) were penta-refractory; 34 pts (89%) were refractory to last-line of treatment; 9 pts (24%) had high tumor burden with ≥60% bone marrow plasma cells; 13 (34%) pts had extramedullary disease; & 11 (29%) pts had high-risk cytogenetics (Del 17p, t(14;16), t(4;14)) at baseline. Median follow-up after CART-ddBCMA infusion was 22 months (range: 9-40 months). CAR+ cells comprised a median 70% (range: 48-87%) of total CD3+ T cells; median vector copy number was 2.2 copies/cell (range: 1.1-3.5); median cell viability was 98% (range: 90-100%), & median cell manufacturing yield was 1174 ×10 6 CAR + cells (range: 470-1626 ×10 6). CART-ddBCMA product characteristics were consistent with the specifications in all the lots, & there were no manufacturing failures. CRS occurred in 36/38 (95%) pts but only 1 pt in DL2 had grade (Gr) 3 CRS & all other cases were Gr≤2. ICANS occurred in 7 pts (5, Gr≤2; 2, Gr3), with 1 Gr3 case in each DL. All cases of CRS & ICANS resolved without further sequalae with management. No cases of off-tumor cell mediated toxicity, delayed neurotoxicity events (i.e., occurring after day 28), or Parkinsonian-like symptoms were observed. All 38 evaluable pts demonstrated investigator-assessed clinical response per 2016 IMWG criteria (ORR, 100%) with 22 sCR, 7 CR (≥CR rate, 76%), 6 VGPR (≥VGPR rate, 92%), & 3 PR. Responses deepened over time & conversion to CR/sCR was observed with longer follow-up (as late as month 12). Of those evaluable for MRD testing to date (n=29), 25 (86%) were MRD-neg at 10 -5. Median duration of response, PFS, & OS were not reached at the time of data-cut because 25 of 38 evaluable pts (66%) had ongoing response. The Kaplan-Meier estimated PFS rates for 6, 12 & 18 months were 92%, 74%, & 67% respectively. Durable responses were also observed in patients with high-risk features (EMD, BMPC ≥ 60%, or B2M ≥ 5.5 at baseline) & high-risk cytogenetics. PFS rates at 6-, 12-, & 18-months are shown in Table 1. Based on the results from the study, a dose of 115 ± 10 ×10 6 cells, consistent with DL1, was recommended for the phase 2 study. Conclusions: Adverse events with CART-ddBCMA, including CRS & ICANS, were manageable & no off-tumor tissue-targeted toxicity, delayed neurotoxicity, or Parkinsonian-like events were observed in the entire cohort at the time of data-cut. Ongoing efficacy results are encouraging, with 100% ORR, including 35 (92%) response of VGPR or better & 29 (76%) with CR/sCR. More importantly, clinical responses were durable with an overall estimated 18-mo PFS rate of 67% with comparable clinical responses seen in ‘high-risk’ patients known to have poor prognosis. Updated data with additional follow-up based on later data-cut will be presented.

Results of the Phase III Randomized Iskia Trial: Isatuximab-Carfilzomib-Lenalidomide-Dexamethasone Vs Carfilzomib-Lenalidomide-Dexamethasone As Pre-Transplant Induction and Post-Transplant Consolidation in Newly Diagnosed Multiple Myeloma Patients

Background. The current standard treatment for transplant-eligible (TE) patients (pts) with newly diagnosed multiple myeloma (NDMM) consists of quadruplet induction with proteasome inhibitors, immunomodulatory agents, dexamethasone and anti-CD38 monoclonal antibody followed by high-dose melphalan and autologous stem-cell transplant (MEL200-ASCT), with subsequent consolidation. The phase III IsKia trial assessed efficacy and safety of isatuximab-carfilzomib-lenalidomide-dexamethasone (IsaKRd) as pre-ASCT induction and post-ASCT consolidation vs KRd. Methods. TE NDMM pts aged <70 years were enrolled and randomized. IsaKRd pts received 4 28-day cycles of Isa: 10 mg/kg IV days 1, 8, 15, 22 cycle 1, followed by 10 mg/kg days 1, 15 cycles 2-4; K: 20 mg/m 2 IV day 1 cycle 1, followed by 56 mg/m 2 IV days 8, 15 cycle 1 and days 1, 8, 15 cycles 2-4; R: 25 mg PO daily days 1-21; d: 40 mg PO days 1, 8, 15, 22; MEL200-ASCT and 4 consolidation cycles with IsaKRd at the same schedule. KRd pts received 4 KRd induction cycles; MEL200-ASCT and 4 KRd consolidation cycles (K, R and d at the same schedule as in the IsaKRd arm). The primary endpoint was the rate of minimal residual disease (MRD) negativity by next-generation sequencing (NGS; 10 -5) after consolidation in the intention-to-treat (ITT) population. MRD was tested in all pts who achieved at least a very good partial response (≥VGPR). Key secondary endpoints were the rate of NGS MRD negativity (10 -5) after induction and PFS. MRD rates were evaluated in an ITT analysis (pts with missing MRD data or who achieved ≤PR were considered as MRD positive). The data cut-off for the analysis was May 22, 2023. Results. 302 pts were enrolled and randomized (151 in both the IsaKRd and KRd arms). Pt characteristics were well balanced between the two arms: median age was 61 vs 60 years, respectively; 18% vs 19% of pts had high-risk (HiR) cytogenetic abnormalities (CA) [del(17p) and/or t(4;14) and/or t(14;16)]; 9% vs 8% had ≥2 HiR CA [double hit; including del(17p), t(4;14), t(14;16) and gain/amp(1q)]. In ITT analysis, the rates of MRD negativity at the 10 -5 cut-off after consolidation (primary endpoint) were 77% vs 67% (OR 1.67; p=0.049) with IsaKRd vs KRd; the respective rates of MRD negativity at the 10 -6 cut-off were 67% vs 48% (OR 2.29; p<0.001); consistent MRD results were detected by next-generation flow. ≥VGPR after consolidation was 94% in both arms; ≥CR 74% vs 72% and sCR 64% vs 67% in the IsaKRd vs KRd arms. The MRD negativity advantage, both at 10 -5 and 10 -6, was retained in all subgroups analyzed ( Figure), with similar benefit in pts with standard-risk (SR) and HiR features. In particular, the 10 -5 MRD negativity rates with IsaKRd were 76% in HiR and 77% in double-hit pts, comparable to the one in SR pts (79%). In the KRd arm, the 10 -5 MRD negativity rates were 58% in HiR and 53% in double-hit pts, inferior to the one in SR pts (70%). The 10 -6 MRD negativity rates with IsaKRd were 72% in HiR, 77% in double-hit pts and 67% in SR pts. The MRD negativity rate after induction (first key secondary endpoint) was also significantly higher with IsaKRd vs KRd (10 -5: 45% vs 26%, OR 2.34, p<0.001; 10 -6: 27% vs 14%, OR 2.36, p=0.004), with a consistent benefit in all subgroups. After induction, the MRD negativity rates in HiR and double-hit pts treated with IsaKRd were: 10 -5, HiR 60%, double-hit 54%; 10 -6, HiR 40%, double-hit 31%. The MRD negativity rates after ASCT were also significantly better with IsaKRd vs KRd (10 -5: 64% vs 49%, OR 1.93, p=0.006; 10 -6: 52% vs 27%, OR 3.01, p<0.001), with a consistent advantage in all subgroups. At the current follow-up (median, 20 months, IQR 18-23), there was no difference in PFS (95% at 1 year in both arms). 55% of pts had ≥1 hematologic adverse events (AEs) with IsaKRd vs 43% with KRd; main grade 3-4 hematologic AEs in IsaKRd vs KRd were neutropenia (37% vs 22%) and thrombocytopenia (15% vs 17%). 41% of pts had ≥1 non-hematologic AEs with IsaKRd vs 37% with KRd, including infections (16% vs 12%), gastrointestinal (7% vs 5%), vascular (2% vs 7%) and cardiac events (1% vs 4%). Discontinuation for toxicity was 6% in IsaKRd vs 5% in KRd arms; treatment-related deaths were 4 with IsaKRd (2 COVID, 1 pneumonia, 1 pulmonary embolism) and 1 with KRd (septic shock). Conclusion. In TE NDMM pts, the addition of isatuximab to KRd induction and consolidation significantly increased MRD negativity rates in every treatment phase as compared to KRd, with no new safety concerns. This benefit was retained in HiR pts.

Phase II Trial of Daratumumab, Bortezomib, Lenalidomide and Dexamethasone in High-Risk Smoldering Multiple Myeloma

Background: Daratumumab, bortezomib, lenalidomide and dexamethasone (D-RVD) has shown high rates of minimal residual disease (MRD) negativity in newly-diagnosed multiple myeloma (MM) and is now a standard regimen in transplant-eligible patients. Lenalidomide has shown to delay progression in patients with high-risk smoldering multiple myeloma (HR-SMM) and curative intent trials with carfilzomib-based therapy and stem cell transplantation have been recently reported in HR-SMM leading to deep responses but with concern for treatment-related toxicities. Thus, we proposed to examine the activity and safety of fixed duration D-RVD in patients with HR-SMM, with MRD-adaptive duration of therapy. Methods: This is a phase II, open-label study evaluating D-RVD in HR-SMM. Eligibility criteria includes HR-SMM per Mayo 2018 “20-2-20” model and other previously established criteria including Mayo 2008 criteria, PETHEMA criteria, evolving type of SMM, and high-risk FISH. Treatment with D-RVD is 2 years (24 cycles) with daratumumab subcutaneous (SQ) per standard dose and schedule, bortezomib 1.3mg/m2 SQ on days 1, 8, 15 for cycles 1-6 then biweekly until completion of cycle 24, lenalidomide 25mg on days 1-21 for cycles 1-6 followed by 15mg d1-21 from cycles 7-24 with weekly low dose dexamethasone. All eligible patients undergo stem cell collection after 6 cycles of therapy. The primary objective is rate of MRD-negativity at 2 years. Secondary objectives include PFS, ORR, and safety. In part 2 of the study, patients that are MRD-positive after 2 years of treatment will be randomized to observation vs continued therapy with daratumumab and lenalidomide for an additional 24 months. The primary objective of part 2 is rate of MRD conversion from positive to negative. Results: At the time of data cut off in May 2023, 38 patients have been enrolled to part 1 with a median follow up of 18 months. The median age is 62 years old (range 36-77) with 23 females (61%) and 15 males (39%). The median plasmacytosis of enrolled patients was 20%, with median M-protein of 2.17 g/dL and median FLC ratio of 8.1. Twenty-four patients (62%) had at least one high-risk FISH abnormality (fifteen with 1q gain, four with t(4;14), one with t(14;16) and one with del 17p). Eight patients (21%) had more than one high-risk FISH abnormality. Most common grade 3 toxicities included neutropenia (13%), ALT increased (8%), and diarrhea (8%). Upper respiratory infections occurred in 61% of patients but were mostly low-grade (COVID-19 infection in 11 patients, 1 with grade 3). No patients discontinued therapy due to toxicity. Of the 35 patients that completed at least 2 cycles of therapy, the ORR is 100% with 43% CR, 34% VGPR and 17% PR with responses deepening over time. Seventy-seven percent of patients achieved VGPR or greater. MRD was evaluable in 22 patients at 6 months with MRD negativity rate of 59% and 14% at thresholds of 10 -5 and 10 -6, respectively. At 12 months, 20 patients were MRD-evaluable with 65% and 20% achieving MRD negativity at 10 -5and 10 -6, respectively. Of the 10 MRD-evaluable patients at 24 months, 60% were MRD negative at 10 -5 and 40% at 10 -6. No patients have progressed on treatment. Stem cell collection was successful in all eligible patients with average stem cell yield of 5.53 x 10 6 CD34+ cells/kg. Conclusions: D-RVD in HR-SMM demonstrates significant activity, including a 100% ORR and high rates of MRD-negative disease, preventing progression to overt myeloma.

Longitudinal Assessment of Minimal Residual Disease (MRD) in the ATLAS Randomized Phase 3 Trial of Post-Transplant Treatment with Carfilzomib, Lenalidomide, and Dexamethasone (KRd) Versus Lenalidomide (R) Alone in Patients with Newly Diagnosed Multiple Myeloma (NDMM)

Introduction The interim results of the ATLAS trial (Dytfeld, Lancet Oncology 2023) suggest a progression-free survival (PFS) benefit for NDMM patients after autologous hematopoietic stem cell transplantation (ASCT) treated with MRD-directed and risk-adapted maintenance using KRd compared to single-agent R. In order to gain a better understanding of the differences in response dynamics and depth achieved by the two regimens, we conducted a detailed analysis of MRD results assessed at multiple timepoints. Methods ATLAS is an ongoing phase 3 trial that randomized 180 patients with NDMM after ASCT to receive maintenance therapy with KRd or R. In the KRd arm, patients with standard-risk cytogenetics who achieved MRD-negativity after cycle 6 de-escalated therapy to receive R alone, starting from cycle 9. MRD assessments were performed using multicolor flow cytometry (MFC) with a limit of detection (LoD) of 10 -5 and next-generation sequencing (NGS) with LoD 10 -6 at screening, cycle 6 (C6), C12, C18, C24, and C36. Patients with MRD>10 -5 were considered MRD positive. When both MFC and NGS results were available, at least one positive result qualified a patient as MRD-positive. In line with the MRD reporting harmonization guidelines (Costa, Leukemia 2021), patients who have not reached a landmark timepoint for analysis were excluded from the denominator. MRD rates between the treatment arms were compared using the chi-square test. PFS and MRD-free survival (death, progression or MRD resurgence counted as an event) were analyzed using the Kaplan-Meier method to calculate survival rates, and the log-rank test was performed to compare the groups. Results We previously reported MRD rates at the end of 6 cycles (Dytfeld, Lancet Oncology2023). In this analysis, MRD results were evaluable for the following number of subjects at the respective timepoints: 180 at screening, 180 at C6, 180 at C12, 179 at C18, 175 at C24, and 160 at C36. All the reported data, including MRD results, response rates, and time to event, were obtained at the cut-off date 31-DEC-2021, as in the Lancet Oncology manuscript. In the landmark analysis, MRD-negativity after C6 was associated with improved PFS for the entire study patient population [HR=0.49 (95% CI: 0.27-0.90), p=0.01]. Although the proportion of MRD-negative patients at screening was higher in the R arm (46/87, 53%) compared to the KRd arm (36/93, 39%, p=0.06), MRD-negative rates were higher in the KRd arm in the subsequent landmark evaluations. The MRD-negativity rates for KRd and R were: 61/93 (66%) vs 41/87 (47%, p=0.01) at C6; 49/93 (53%) vs 41/87 (47%, p=0.46) at C12; 48/93 (52%) vs 35/86 (41%, p=0.14) at C18; 43/90 (48%) vs 26/85 (31%, p=0.02) at C24; 34/82 (41%) vs 16/78 (21%, p= 0.004) at C36. These findings were consistent with a higher number of patients in the KRd arm who converted from MRD-positivity at screening to MRD-negativity at any timepoint (Figure 1). Of the 50 patients with detectable MRD at screening in the KRd arm, 33 (66%) achieved MRD-negativity as their best response. Among them, 24 achieved MRD-negativity at the end of C6, with 2 patients converting as late as C24. The numbers were significantly lower for the R arm, with 14 out of 32 (44%) MRD-positive patients at screening achieving MRD-negativity (p=0.047). Sustained MRD-negativity for at least 12 months was reached in 51 out of 93 patients (55%) in the KRd arm and in 36 out of 87 (41%) in the R arm (p=0.06). Those who achieved sustained MRD-negativity have had significantly longer PFS (HR=0.35 (0.20-0.59), p<0.0001). Among patients with sustained MRD-negativity, patients in the KRd arm had superior PFS [HR=0.30 (0.12-0.79), p=0.01], and MRD-free survival [HR=0.42 (0.20-0.89), p=0.02, Figure 2]. In the KRd arm, sustained MRD-negativity was confirmed in 32 out of 41 (78%) patients who had de-escalated therapy from KRd to R. In this group there were 8 events (25%) of progressive disease or MRD resurgence, which compared favorably to 17/36 (47%, p=0.057) events observed in the R arm. Conclusions The improved PFS in patients with NDMM receiving post-ASCT KRd maintenance may be attributed to higher rates of MRD conversion and longer duration of MRD-negativity. Importantly, this benefit, compared to R alone, appears to be sustained even in the subset of patients who received only 8 cycles of MRD-directed, risk-adapted KRd and subsequently de-escalated to R alone.

Alnuctamab (ALNUC; BMS-986349; CC-93269), a 2+1 B-Cell Maturation Antigen (BCMA) × CD3 T-Cell Engager (TCE), Administered Subcutaneously (SC) in Patients (Pts) with Relapsed/Refractory Multiple Myeloma (RRMM): Updated Results from a Phase 1 First-in-Human Clinical Study

Introduction : ALNUC, a 2+1 TCE with bivalent binding to BCMA, is under investigation in a phase 1 trial (NCT03486067) in pts with triple-class exposed RRMM previously treated with ≥ 3 lines of therapy (LOTs). IV-administered ALNUC demonstrated durable responses (median duration of response, 33.6 mo). However, due to a high frequency of cytokine release syndrome (CRS; 76% of pts), including grade ≥ 3 events (7% of pts), the trial pivoted to SC administration of ALNUC. This resulted in a markedly improved safety profile, allowing escalation to higher target doses, while showing promising antitumor activity (Wong SW et al. EHA 2023. Abstract P883). We present updated data for SC ALNUC in pts with RRMM treated in the phase 1 study. Methods : Pts with RRMM who had received ≥ 3 LOTs, including an immunomodulatory drug (IMiD ®), a proteasome inhibitor, and an anti-CD38 therapy, were eligible. SC ALNUC was given on day (D) 1, 4, 8, 15, and 22 of cycle 1 (C1), QW in C2-3, Q2W in C4-6, and Q4W in C7 and beyond (28-d cycles). Step-up doses were given on C1D1 (3 mg) and C1D4 (6 mg), and target doses (10, 15, 30, or 60 mg) on C1D8 and thereafter. Target doses of 10, 30, and 60 mg were tested in dose expansion. Safety and tolerability were primary objectives. Secondary objectives included preliminary efficacy and pharmacokinetics. The data cutoff for the results included herein was Apr 3, 2023; updated data will be presented. Results : Of 73 pts treated with SC ALNUC in dose escalation (target dose: 10 mg, n = 6; 15 mg, n = 4; 30 mg, n = 6; 60 mg, n = 7) and dose expansion (target dose: 10 mg, n = 19; 30 mg, n = 21; 60 mg, n = 10), median age was 64 y; 58% were male. Pts had median of 4 prior regimens (range, 3-14); 96% were refractory to last LOT, 100%/78% had triple-class/penta-drug exposed MM, and 63%/19% had triple-class/penta-drug refractory MM. Median follow-up was 7.4 mo (range, 0.5-19.9). All-grade/grade ≥ 3 treatment-emergent adverse events (TEAEs) occurred in 99%/81% of pts; most common were CRS (56%/0%), neutropenia (55%/45%), anemia (47%/27%), and thrombocytopenia (37%/16%). All-grade/grade ≥ 3 infections occurred in 62%/16% of pts; infections occurring in ≥ 10% of pts were COVID-19 (23%/3%) and upper respiratory tract infections (12%/0%). Infections of special interest included grade 2 cytomegalovirus reactivation in 1 pt (1.3%); there were no grade ≥ 3 infections of special interest. Median time to CRS was 3 d (range, 1-20), with a median duration of 2 d (range, 1-11). CRS was most common after the first step-up dose (40% of pts). Of 887 doses administered at the fourth dose and beyond, the frequency of CRS per dose was < 1%. Two pts had grade 1 neurotoxicity suspected related to SC ALNUC; no grade ≥ 2 neurotoxicity was observed. One pt discontinued treatment due to a TEAE (grade 3 metastatic colon cancer not suspected related to treatment); 1 treatment-related death (cerebral hemorrhage) occurred at the 60-mg target dose. Overall response rate (ORR) was 54% (39 of 72 efficacy-evaluable pts treated with SC ALNUC) across all doses, with responses deepening over time (Figure). ORR was 63% (27/43) at target doses ≥ 30 mg and 69% (18/26) at the 30-mg target dose. Median time to response was 1.2 mo (range, 0.9-4.0) and 77% (30/39) of responses were ongoing at data cutoff. Among efficacy-evaluable pts, median PFS was 10.1 mo (95% CI, 2.8-16.6) across all dose levels. For the 30-mg target dose, at a median follow up of 9.3 mo, median PFS was not reached (95% CI, 4.7-NA) with a 12-mo PFS of 53% (95% CI, 30-71). Among the 39 pts who achieved a response, 28/28 pts (100%) with evaluable minimal residual disease (MRD) samples were MRD-negative (10 −5 sensitivity by flow cytometry) at C2D1, C4D1, C6D1, or C8D1; of the 18 pts who achieved a response at the 30-mg target dose, 14/14 pts (100%) with available MRD data were MRD-negative. Preliminary population pharmacokinetic analysis estimated ~60% SC ALNUC bioavailability with a 14-d half-life. Observed trough concentrations at the 30-mg target dose exceeded levels predicted for efficacy by C2D1. Hallmark pharmacodynamic effects of TCEs were observed. Conclusions : SC ALNUC continued to demonstrate a safety profile consistent with the drug class and a low rate of severe infections. Across doses, responses were durable and deepened over time, with a high proportion of responders achieving MRD negativity. High antitumor activity was observed at target doses ≥ 30 mg and specifically at the 30-mg target dose. Enrollment in the phase 1 study is ongoing.

A Real-World Evidence on Effectiveness and Safety of Blinatumomab in Patients with B-Cell Acute Lymphoblastic Leukemia

Introduction Blinatumomab, a bispecific T-cell antibody, has emerged as a novel therapy with a promising efficacy and tolerable safety in patients with B-cell acute lymphoblastic leukemia (B-ALL). However, there is a paucity of data on blinatumomab for patients with newly diagnosed and relapsed/refractory (R/R) B-ALL in frontline and relapsed settings outside the clinical trials. This study aimed to describe the treatment patterns, effectiveness and safety of blinatumomab in Chinese patients with B-ALL. Methods In this retrospective observational study, data of patients with B-ALL who received at least one dose of blinatumomab in frontline or relapsed settings between August 2021 and June 2023 were collected from electronic medical data of the Department of Haematology of the First Affiliated Hospital of Soochow, China. The primary endpoint of the study was the treatment pattern of blinatumomab therapy, including median treatment cycles. Secondary endpoints included complete remission (CR)/CR with incomplete blood cell recovery (CRi) rate, minimal residual disease (MRD) negativity (i.e., complete MRD remission, defined as MRD <0.01%), median event-free survival (EFS) and 1-year EFS rate, median overall survival (OS) and 1-year OS rate, duration of response (DOR) and adverse events (AEs). Results In total, 96 patients with B-ALL (53 males and 43 females) were included. Of these, 53 received frontline treatment (blinatumomab used for first line remission induction: n=6; first line consolidation: n=39; first line induction or consolidation unknown: n=8), and 43 were R/R patients (blinatumomab for remission re-induction: n=28; R/R consolidation: n=14; R/R re-induction or consolidation unknown: n=1). The median age was 34 years (range: 11-67). Among R/R patients, 18 (18.8%), 12 (12.5%) and 13 (13.5%) had received 2, 3, and ≥3 previous lines of treatments, respectively. Sixteen patients were refractory to the last treatment. Among patients using blinatumomab for consolidation, MRD status at the start of therapy was positive in 29 (30.2%), and negative in 23 (24.0%) patients. Most of the patients (66.7%) received 1 cycle of blinatumomab followed by 2 (20.8%), 3 (7.3%), 4 (4.2%), and 5 (1.0%) cycles of the drug. The median treatment cycle was 1 (range: 1-5) with a median follow-up of 205 days (range: 15-652). In frontline treatment, all those using blinatumomab for remission induction and first line unknown status achieved CR with the CR/CRi rate of 100% (14/14) after blinatumomab. In patients with evaluable MRD (n=47) in the frontline setting, 87.2% (n=41) achieved MRD negativity within the 2 cycles of blinatumomab. In the following cycles, 3 more patients achieved MRD remission with overall complete MRD remission rate of 93.6% (44/47). In R/R re-induction patients, the CR/CRi rate was 50% (14/28) after blinatumomab treatment. Complete MRD remission rate in R/R patients who achieved CR within 2 cycles of blinatumomab was 73% (19/26). Median EFS was not reached (NR) in both frontline and R/R patients and the 1-year EFS rate was 90.8% (95% CI: 67% - 97%) and 55.1% (95% CI: 30% - 74%), respectively (Figure 1). Stratification of EFS by CR status at blinatumomab initiation showed 1-year EFS rate of 93.8% and 100% in first line consolidation and remission induction patients, respectively, whereas, R/R consolidation and re-induction patients showed 1-year EFS rate of 66.8% and 59.3%, respectively. None of the frontline treated patients died until the last follow-up time. In R/R patients the median OS was not reached and the 1-year OS rate was 70.9% (95% CI: 50% - 84%). OS stratified by CR status in R/R patients showed 1-year OS of 87.5% in consolidation and 69.9% in re-induction patients. Median DOR was NR in both frontline and relapsed settings. Seven (7.3%), and 3 (3.1%) patients reported any grade, and grade ≥3 cytokine release syndrome, respectively. Immune effector cell-associated neurotoxicity syndrome was reported by 1 patient (grade ≥3). Infection of any grade and grade ≥3 was reported by 6 (6.2%) and 4 (4.2%) patients, respectively. Increase in liver enzymes and neutropenia were observed in 1 patient (grade ≥3) each. Conclusion This study showed that using blinatumomab for remission induction and consolidation with one to five cycles was effective in the treatment of patients with B-ALL in the frontline as well as relapsed settings and had a tolerable safety profile.

Endpoint Surrogacy in Chronic Lymphocytic Leukemia: A Pooled Analysis of the German CLL Study Group

Introduction Overall survival (OS) is generally considered the most patient-relevant endpoint in oncology trials, however, its implementation can entail several challenges in the context of chronic lymphocytic leukemia (CLL): 1) The competing survival risk due to comorbidities in the mostly elderly CLL patient population; 2) the high efficacy of targeted therapies warrant longer observation periods or extensive patient recruitment, which can be operationally challenging; 3) the interference with increasingly potent relapse therapies, which can neutralize differences of efficacy of first line regimen. Hence, surrogate endpoints, such as progression-free survival (PFS), overall response or complete response rate (ORR, CR) or minimal residual disease (MRD), are commonly used in CLL research. However, data supporting a correlation between surrogate endpoints and OS in the treatment for CLL is scarce. Here, we present a large, systematic analysis of over 4000 patients (pts) treated in studies of the German CLL Study Group (GCLLSG) to determine the adequacy of surrogate endpoints in clinical trials for pts with CLL. Methods We analysed twelve phase II and phase III trials of the GCLLSG spanning from 1999 to 2022. Only pts receiving first-line therapy were included in the analysis. To determine correlation, the Kaplan-Meier survival function was estimated for both OS and PFS for each study separately. From these functions, the probability of survival (OS and PFS) was estimated at different time points. These pairs of time points were then correlated across the studies, with each pair of probabilities weighted by the number of pts in each corresponding study using Spearman's correlation coefficients. Additionally, we compared OS according to MRD and iwCLL response status at end-of-treatment (for fixed-duration regimens) or end-of-induction-treatment (for MRD-guided treatments) (EO[I]T) using Kaplan-Meier functions calculated from the time point of MRD assessment in peripheral blood. EO(I)T ranged from month 9 to month 15 after treatment initiation, depending on the study protocol. Results The full analysis set comprised 4237 pts. The median observation time was 67 months. Median age was 64 years (range 27 - 90). 45.1% of pts were older than 65 years. 3159 pts (74.6%) had received chemo/chemoimmunotherapy (C/CIT), whereas 1078 (25.4%) were treated with targeted therapies. There were 2114 progressive disease (PD) events and 1211 deaths captured within the trial data. The Spearman's Rho of the estimated survival probabilities for the time points 12/24, 24/36, 36/48 and 60/72 months (PFS/OS) was 0.95, 0.96, 0.94 and 0.92, respectively ( Panel A). Focussing on pts with confirmed OS event (n=1211), the Spearman's Rho between PFS and OS in months was 0.66 for pts receiving chemo/chemoimmunotherapy and 0.88 for pts receiving targeted treatment. ORR and CR rate was 89.8% and 31.5%, respectively. Pts with a CR had a significantly longer PFS (HR 0.38, 95% CI 0.34-0.42, p <0.001) and OS (HR 0.39, 95% CI 0.33- 0.46, p <0.001) compared to pts with non-CR. MRD measurements at the EO(I)T were available for 2521 pts (59.5%), of which 39% were treated with targeted agents. Rates of undetectable (<10 -4), intermediate (≥10 -4 and <10 -2) and high MRD (≥10 -2) were 59.1%, 21.7%, 19.3%, respectively, across treatment groups. The median OS for undetectable and intermediate MRD was not reached and 60.7 months for high MRD status ( Panel B). The estimated 60-month OS was 84.6%, 71.3% and 51.1%, respectively. Accordingly, median PFS for uMRD was 61.8 months and 60-month PFS was 52.6%. In pts ≤65 years of age, median OS was not reached with undetectable or intermediate MRD and 70.5 months in pts with high MRD status. In pts >65 years, median OS was not reached for uMRD and was 75.2 and 58.8 months, respectively, for pts with intermediate or high MRD. The corresponding hazard ratios for high versus uMRD status at EO(I)T were 3.33 (95% CI 2.57 - 4.3) in older and 5.89 (4.15 - 8.35) in younger pts. Conclusion In this large analysis of 12 prospective CLL trials, we found a robust correlation between PFS and OS, thereby supporting the use of PFS as a surrogate endpoint in clinical studies. More importantly, the MRD status at EO(I)T was associated with OS across all treatment modalities, demonstrating its utility in identifying pts with potentially dismal outcomes and providing a rationale for MRD-guided treatment strategies.

Digital Polymerase Chain Reaction (dPCR) Versus Flow Cytometry (FC), a Validation Study for CAR-T Cell Product Optimal Detection

CONCLUSIONS Adoptive immunotherapy with Chimeric Antigen Receptor - T cells (CAR-T), has revolutionized hematological treatment mainly in relapsed/refractory (r/r) B-cell malignancies. CAR-T cells constitute challenging living drugs with heterogeneous in vivo cellular kinetics and adverse side effects that emphasizes the importance of its accurate detection and monitoring. Diagnostic assays are required for precise CAR-T quantification. Digital PCR (dPCR) is characterized by a high specificity, sensitivity and reproducibility, therefore we developed a study to implement this technique for CAR-T detection and compare its efficacy against Flow Cytometry (FC). Duplex dPCR assays were performed to concomitantly amplify CAR and RPP30 (reference gene) sequences using ddPCR Expert Design Assay: CD-19 CAR-T Assay (Bio-Rad, California, USA) with QIAcuity Digital PCR System and data analysis with QIAcuitySoftware Suite (QIAGEN, Germany). To assess sensitivity, a Axicabtagene Ciloleucel (Axi-Cel ®) original product obtained from leftovers's infusion bag patient was employed to perform dPCRs on serial dilutions using genomic DNA(gDNA) from a wild type (WT) patient. Specificity was ensured using WT and no template controls (NTC). Two independent dPCR assays with replicates for each sample were conducted to assess reproducibility. For FC comparative study, CAR-T cells percentage (%CAR-T) was determined by both techniques at variable post-infusion intervals (n=210) in different sample types, peripheral blood (n=205) and cerebrospinal fluid (n=5). Anti-FMC63 scFv Antibody, Mouse IgG1 (Acro biosystems) was employed, using FACSCanto II®, Becton-Dickinson Biosciences with FACSDiva software ® (V8.0; BD) and InfinicytTM software (Cytognos SL, Salamanca, Spain), for data analysis. Correlation coefficients were determined using two-tailed Pearson statistics with a confidence interval of 95%. Statistical analyses were made with SPSS Software (IBM, Germany). The dPCR data collected of 2 independent dPCR assays revealed a good split between the negative and positive partitions for the targets evaluated, showing a progressive decrease of the %CAR-T detected (63,88% - 4,12% - 0,77% - 0,08% - 0,01% - 0,00%). This reduction is correlated with the dilution factor applied to the series with an initial concentration of 50ng/µL both for CAR-T original product and WT gDNA. WT and NTC samples were negative with a SD=0; %CV=0, intra and inter-assays, evidencing thus the specificity of the technique. Positivity of the last (1 pg/µL) samples revealed a maximum sensitivity of 0.009 %CAR-T, threshold below which false positive results would be considered. WT gDNA did not influence the assay's sensitivity. 3 replicates of each sample and 2 independent dPCR assay were performed to study potential variations, exhibiting an excellent intra and inter-assay reproducibility with a minimal SD across dilutions ( Table.1.) Comparative study with FC revealed a light correlation between techniques with a Pearsons's correlation coefficient (R=0,553) ( p<0,001). Differences among both were enhanced for Minimal Residual Disease (MRD) evaluation from 60 days post-infusion monitoring (R=0,58) ( p=0,066) in which CAR-T cells can be detected applying dPCR up to 2 years and 9 months post-infusion, whereas being undetectable by FC. Complex CAR-T in vivo kinetics enhances the need for optimal diagnostic and monitoring techniques. dPCR is an ideal tool for precise CAR-T therapy evaluation with a higher grade of specificity, sensitivity and reproducibility than FC, mainly for MRD assessment. dPCR implementation and the establishment of standardized protocols across centers is required to improve CAR-T biology knowledge with a direct benefit on patient care.

Integrated analysis of randomized controlled trials evaluating bortezomib + lenalidomide + dexamethasone or bortezomib + thalidomide + dexamethasone induction in transplant-eligible newly diagnosed multiple myeloma.

Providing the most efficacious frontline treatment for newly diagnosed multiple myeloma (NDMM) is critical for patient outcomes. No direct comparisons have been made between bortezomib + lenalidomide + dexamethasone (VRD) and bortezomib + thalidomide + dexamethasone (VTD) induction regimens in transplant-eligible NDMM. An integrated analysis was performed using patient data from four trials meeting prespecified eligibility criteria: two using VRD (PETHEMA GEM2012 and IFM 2009) and two using VTD (PETHEMA GEM2005 and IFM 2013-04). The primary endpoint was met, with VRD demonstrating a noninferior rate of at least very good partial response (≥ VGPR) after induction vs VTD. GEM comparison demonstrated improvement in the ≥ VGPR rate after induction for VRD vs VTD (66.3% vs 51.2%; P = .00281) that increased after transplant (74.4% vs 53.5%). Undetectable minimal residual disease rates post induction (46.7% vs 34.9%) and post transplant (62.4% vs 47.3%) support the benefit of VRD vs VTD. Treatment-emergent adverse events leading to study and/or treatment discontinuation were less frequent with VRD (3%, GEM2012; 6%, IFM 2009) vs VTD (11%, IFM 2013-04). These results supported the benefit of VRD over VTD for induction in transplant-eligible patients with NDMM. The trials included are registered with ClinicalTrials.gov (NCT01916252, NCT01191060, NCT00461747, and NCT01971658).

Efficacy and safety of daratumumab in the treatment of relapsed/refractory multiple myeloma: A meta-analysis of randomized controlled trials.

Daratumumab as a monoclonal antibody has shown promising results in the treatment of relapsed/refractory multiple myeloma (RRMM). However, the efficacy and safety of daratumumab-based regimens compared to control regimens have not been fully established. The search was conducted using electronic databases (PubMed, Web of Science, Embase, and Cochrane Central Register of Controlled Trials databases) up to December 2022. We conducted a meta-analysis of randomized controlled trials that evaluated the efficacy and safety of daratumumab in the treatment of RRMM. Data were extracted from eligible studies and were presented as hazard ratio or risk ratio (RR) with 95% confidence interval (CI). A total of 5 randomized controlled trials comprising 2003 patients were included in this meta-analysis. The results showed that daratumumab-based regimens significantly improved progression-free survival compared to control regimens (hazard ratio = 0.44, 95% CI 0.32-0.60, P < .00001). Additionally, daratumumab-based regimens significantly improved overall response rate compared to control regimens (RR = 1.25, 95% CI 1.16-1.36, P < .00001). the rate of minimal residual disease was also significantly higher in the daratumumab-based regimens (RR = 6.10, 95% CI 4.09-9.11, P < .00001). However, there was an increased risk of pneumonia, upper respiratory tract infections, and diarrhea in the daratumumab-based regimens. Our results suggest that daratumumab-based regimens are effective in the treatment of RRMM, improving progression-free survival, minimal residual disease, and overall response rate. However, there is an increased risk of pneumonia, upper respiratory tract infections, and diarrhea. Further studies are needed to determine the long-term safety and efficacy of daratumumab in the treatment of multiple myeloma.

P-068 Implementation of next generation sequencing as best tool for routine evaluation of minimal residual disease in the daily practice of multiple myeloma patients

P-068 Implementation of next generation sequencing as best tool for routine evaluation of minimal residual disease in the daily practice of multiple myeloma patients

P-083 The role of minimal residual disease evaluation for patients with multiple myeloma

P-083 The role of minimal residual disease evaluation for patients with multiple myeloma

Androgen deprivation therapy plus abiraterone or docetaxel as neoadjuvant therapy for very-high-risk prostate cancer: a pooled analysis of two phase II trials.

Objective: The study aimed to compare the efficacy and safety of androgen deprivation therapy (ADT) with abiraterone or docetaxel versus ADT alone as neoadjuvant therapy in patients with very-high-risk localized prostate cancer. Methods: This was a pooled analysis of two single-center, randomized, controlled, phase II clinical trials (ClinicalTrials.gov: NCT04356430 and NCT04869371) conducted from December 2018 to March 2021. Eligible participants were randomly assigned to the intervention (ADT plus abiraterone or docetaxel) and control (ADT alone) groups at a 2:1 ratio. Efficacy was evaluated by pathological complete response (pCR), minimal residual disease (MRD), and 3-year biochemical progression-free survival (bPFS). Safety was also analyzed. Results: The study included 42 participants in the ADT group, 47 in the ADT plus docetaxel group, and 48 in the ADT plus abiraterone group. A total of 132 (96.4%) participants had very-high-risk prostate cancer, and 108 (78.8%) had locally advanced disease. The ADT plus docetaxel group (28%) and ADT plus abiraterone group (31%) had higher rates of pCR or MRD (p = 0.001 and p < 0.001) compared with the ADT group (2%). The 3-year bPFS was 41.9% (95% CI: 26.6-57.2), 51.1% (95% CI: 36.8-65.4), and 61.2% (95% CI: 45.5-76.9), respectively. Significant difference was found among groups in terms of bPFS (p = 0.037). Conclusion: Compared with ADT alone, neoadjuvant therapy with ADT plus docetaxel or abiraterone could achieve better pathological outcomes (pCR or MRD) for very-high-risk localized prostate cancer. The ADT plus abiraterone group showed longer bPFS than ADT alone. The combination regimens were tolerable.

Intensified conditioning regimen with fludarabine combined with post-transplantation cyclophosphamide for haploidentical allogeneic hematopoietic stem cell transplantation in children with high-risk acute leukemia

ABSTRACTObjective:Post-transplantation cyclophosphamide (PTCy) can reduce the incidence of graft versus host disease (GVHD) and this intervention is often applied on adults with hematologic malignancy. However, the high relapse rate hinders the development of the intervention and data of PTCy used on children with hematologic malignancy remains limited. In order to overcome issue of high relapse rate in PTCy treatment, we used fludarabine (Flu), enhanced dose of cytarabine (Ara-C, 9 g/m2), busulfan (Bu), Cy, anti-thymocyte globulin (ATG) combined with PTCy for an intensified conditioning regimen.Methods:A total of 22 children with acute leukemia received intensified PTCy conditioning regimen (PTCy intensified group). We matched with 18 children who received modified Bu-Cy and ATG conditioning regimen in the same period (ATG group).Results:The two-year cumulative incidences of grade II–IV acute GVHD was significantly lower in PTCy intensified group (13.6 ± 7.7% vs 38.9 ± 11.5%, P = 0.048). Two-year GVHD-free relapse free survival (GRFS) in PTCy seems to be better among the increment group despite not being significant (63.3 ± 10.3% vs 35.4 ± 11.9%, P = 0.092). The positive rate of minimal residual disease after transplantation was significantly lower than that before transplantation (20.0% vs 2.5%, P = 0.029).Conclusion:In conclusion, ATG and PTCy combined with Flu-based increased intensity conditioning regimen is effective for acute leukemia in children. It could reduce GVHD rate significantly and potentially improve GRFS.

Efficacy and safety of add-on anti-CD20 monoclonal antibody to Bruton tyrosine kinase inhibitor treatment for chronic lymphocytic leukemia: a meta-analysis

The efficacy of Bruton tyrosine kinase inhibitors (BTKi) remains suboptimal in chronic lymphocytic leukemia (CLL) treatment. A systematic review and meta-analysis were conducted to compare the outcomes of combining anti-CD20 monoclonal antibodies (mAb) with BTKi therapy versus BTKi monotherapy for patients with CLL. We searched for relevant studies in the Pubmed, Medline, Embase, and Cochrane databases until December 2022. We estimated the effective results using a hazard ratio (HR) for survival outcomes and relative risk (RR) for response outcomes and safety. Four randomized controlled trials (including 1056 patients) were found until November 2022 and fulfilled the inclusion criteria. Progression-free survival was significantly improved with the addition of anti-CD20 mAb to BTKi over BTKi (HR 0.70, 95% confidence interval (CI) 0.51–0.97), whereas pooled analysis of overall survival did not favor combination therapy compared to BTKi monotherapy (HR 0.72, 95% CI 0.50–1.04). Combination therapy was related to a statistically better complete response (RR, 2.03; 95% CI 1.01 to 4.06) and an undetectable minimal residual disease rate (RR, 6.43; 95% CI 3.54 to 11.67). The risk of grade ≥ 3 adverse events was comparable between the two groups (RR, 1.08; (95% CI 0.80 to 1.45). Overall, adding anti-CD20 mAb to BTKi revealed superior efficacy than BTKi alone in untreated or previously treated CLL patients without affecting the safety of single-agent BTKi. Conducting further randomized studies to confirm our results and determine the optimal therapy for managing patients with CLL is essential.

Utility of surgically documented minimal residual disease as a therapeutic target and early surrogate of frontline treatment outcomes in ovarian cancer.

5549 Background: Cure rates for patients with advanced stage ovarian cancer have not changed over the last four decades likely due to inability to eradicate residual cancer cells after frontline therapy. Identifying clinically undetectable minimal residual disease (MRD) after frontline therapy by second look laparoscopy (SLL) has potential to a) uncover mechanisms of chemoresistance, b) identify MRD-specific therapeutic targets, and c) allow for earlier intervention with investigational therapies. The objective of this study is to describe the initial safety and feasibility of SLL and illustrate clinical pathologic correlates. Methods: This IRB-approved observational, single-center study includes patients with epithelial high-grade ovarian cancer with complete CA-125 and radiologic response after frontline treatment who underwent SLL from 4/2017-12/2022. Patients were subsequently offered standard of care or investigational maintenance therapy options based on homologous recombination deficiency (HRD) and MRD status. Summary statistics described the study population, chi-square tests compared categorical variables, and progression free survival (PFS) based on MRD status was estimated using Kaplan-Meier method and compared using log rank test. Results: 64 patients underwent SLL with a median of 8 biopsies (range 1-16). The majority of patients had stage III-IV disease (89%), and high-grade serous histology (89%). Approximately half (52%) of patients underwent neoadjuvant chemotherapy (NACT) with interval tumor reductive surgery (TRS). MRD was present in 28 patients (44%), and the presence of MRD was associated with a worse PFS (HR 3.1, 95% CI 1.5-6.3; 9.2 vs 24.6 months; P=0.002). MRD was more frequent among NACT recipients compared to those who underwent primary TRS (61% vs 26%, P=0.005), those with HRD negative tumors (63% vs 22%, P=0.003), and those with R1 versus R0 resections (71% vs 35%, P=0.012). Of patients with MRD, 20 patients (71%) received bevacizumab until progression as part of a clinical trial (NCT02884648), 3 (11%) received bevacizumab off trial, 4 (14%) received a PARP inhibitor (all HRD positive) and 1 received other therapy. There was one (1.6%) intraoperative complication requiring conversion to laparotomy. Conclusions: SLL is feasible, overall safe, and detected MRD in 44% of ovarian cancer patients who were in radiologic and CA-125 remission after frontline therapy. MRD rates were higher in patients who received NACT and HRD negative patients, and PFS was significantly longer in patients without residual disease. MRD rate by SLL may have utility as an early surrogate for efficacy in trials evaluating novel frontline investigational therapies. Knowledge of MRD status in this patient population enables interventional, observational, and translational investigations, as well as personalized prognostic counseling.