Bone Marrow MRD Research Articles

Clinical efficacy and immune response of BCL-2 inhibitors combined with hypomethylating agents in the treatment of acute myeloid leukemia

ObjectiveAcute myeloid leukemia (AML) is a malignant clonal proliferative disease with a high mortality rate. The combination therapy of BCL-2 inhibitor Venetoclax (VEN) and hypomethylating agents (HMAs) has significant anti-leukemia activity.MethodsWe analyzed the efficacy, safety and immune response characteristics of AML patients who were unfit for high-dose chemotherapy and accepted the medication of VEN + HMAs.ResultsAfter VEN + HMAs treatment, 31 newly diagnosed AML patients had the morphologic leukemia-free state rate (MLFS%) of 80.6% (25/31), complete response rate (CR%) of 54.8% (17/31), the minimal residual disease negative rate (MRD-%) of 51.6% (16/31), and the median progression-free survival (PFS) of 14 months. After treatment, the proportion of bone marrow primitive cells, the MRD level, white blood cell (WBC) count, fibrinogen (FIB) level and the proportion of B cells were significantly decreased. The red blood cell (RBC) count, hemoglobin (HGB) level, platelet count (PLT) count, activated partial thromboplastin time (APTT), the proportion of total T cells, CD8 + T cells and the IFN-γ level were significantly increased. After VEN + HMAs treatment, 12 relapsed AML patients had a MLFS% of 50% (6/12), CR% of 33.3% (4/12), MRD-% of 25% (3/12), and a median PFS of 7 months. After treatment, the proportion of bone marrow primitive cells and MRD level were slightly decreased, the proportions of CD8 + T cells and NK cells were significantly increased, the proportion of B cells and IL-10 level were significantly decreased. 12 AML patients who receive microtransplantation (MST) treatment using VEN + HMAs as a pretreatment regimen had a PFS of 20.5 months, which was much greater than VEN + HMAs group alone. Hematological recovery was better in the MST group with significantly increased RBC count, HGB level and PLT count. The most common adverse events were myelosuppression, agranulocytosis, infection and cardiovascular toxicity. No fatal adverse events were reported.ConclusionThe combination of BCL-2 inhibitors and HMAs had good efficacy and safety in AML patients who were unfit for high-dose chemotherapy, which may improve the immune microenvironment and enhance anti-leukemia immune response.

Orelabrutinib, Fludarabine, Cyclophosphamide, and Obinutuzumab (OFCG) for First-Line Treatment of Chronic Lymphocytic Leukemia: A Multicenter, Investigator-Initiated Study (cwCLL-001 Study)

Background: A phase II trial has shown, first-line treatment with iFCG (ibrutinib, fludarabine, cyclophosphamide, and obinutuzumab) led to a bone marrow (BM) undetectable minimal residual disease (uMRD) rate of 98% (44/45) as best response in treatment-naïve patients with chronic lymphocytic leukemia/small lymphocytic leukemia (CLL/SLL). But this study[1] does not include patients with unmutated immunoglobulin heavy⁃chain variable region gene ( IGHV) and/or del(17p)/ TP53 mutation, and ibrutinib was the first generation BTK (BTKi) which had relatively high off-target adverse effects (AEs). Our study has demonstrated the efficacy and safety of the second generation BTKi orelabrutinib in patients with relapsed/refractory CLL [2]. Therefore, we used orelabrutinib (O), and initiated the phase II OFCG trial in younger, fit patients with previously untreated CLL/SLL unrestricted by IGHV mutation status and del(17p)/ TP53 aberrations (cwCLL-001 study, NCT05322733). Methods：This is a multicenter, open-label, non-randomized phase II study for previously untreated patients with CLL/SLL without restriction by del(17p)/ TP53 aberrations and/or IGHV mutation status. A 7-day lead-in period with single-agent oral orelabrutinib（150 mg daily）was given in all patients, followed by OFCG regimen which consisted of orelabrutinib, intravenous Obinutuzumab, fludarabine and cyclophosphamide for up to three 28-day cycles. MRD was detected by 8 multi-color flow cytometry (FCM) at 10 -4 sensitivity and cloneSEQ using NGS (next generation sequencing) assay with a sensitivity of up to 10 −6. If the patients could achieve undetectable MRD in BM, they will discontinue FC and receive 3 cycles of OG (orelabrutinib and obinutuzumab). Otherwise, the patients will receive another 3 cycles of OFCG. Patients will discontinue obinutuzumab if they achieve BM uMRD after 6 cycles and continue six additional cycles of orelabrutinib; all other patients will receive six cycles of OG. Patients who achieved BM uMRD after 12 cycles discontinue all treatments, otherwise will continue orelabrutinib for up to additional 1 year (Fig. 1). The primary endpoint is the percentage of uMRD in BM after 6 cycles by FCM (at 10 -4 sensitivity). The secondary endpoint is the percentage of uMRD in BM and peripheral blood (PB) at other key time points by FCM, best overall response rate (ORR), complete response rate (CRR), progression-free survival (PFS), 2- and 3-year PFS rate, duration of response (DOR), overall survival (OS), 3-year OS rate as well as safety. The percentage of uMRD by NGS is an exploratory endpoint. Results：From 30 May 2022 to 30 Jun 2023, 25 patients were enrolled. Median age was 49 years old (range, 23-62). Unmutated IGHV, TP53 mutation/del(17p) and del(11q) were detected in 56.5% (13/23), 16.0% (4/25), and 24.0% (6/25) of patients, respectively. At data cut off (30 Jun 2023), 19 patients completed 3 cycles of OFCG and were evaluable. 75% (15/20, 1 patient who off study was assessed at the end of C2 cycle) of patients achieved PB uMRD and 57.9% (11/19) achieved BM uMRD by FCM, ORR and CR/CRi rate was 100% (18/18) and 38.9% (7/18) (Fig. 2). One patient died after cycle 3 due to COVID-19 infection. 16 patients completed 6 cycles, 14 of them were evaluable and achieved deeper response irrespective of different strategies during cycle 4 to 6, PB uMRD and BM uMRD was 100% (14/14) and 85.7% (12/14) by FCM, and the ORR and CRR was 100% (14/14) and 57.1% (8/14), respectively. In IGHV unmutated subgroup, ORR was 100% (10/10) with 50% (5/10) CRR, 87.5% (7/8) patients achieved BM uMRD by FCM after cycle 6. The results of MRD response by NGS assay will be presented in the formal report. 91.7% patients experienced at least one treatment emergent AE at the data cutoff. Most AEs were mild and tolerable. The most frequent AEs (≥10% of any grade) were neutropenia, leukopenia and thrombocytopenia. No bleeding or cardiovascular AEs greater than grade 3 occurred in these patients. Overall, OFCG demonstrated a favorable safety profile. Conclusion：This is the first clinical trial exploring the efficacy and safety of the second generation BTKi plus chemoimmunotherapy in patients with CLL. The OFCG regimen shows a rapid and deep molecular remission with a pleasant safety profile in the TN CLL patients including the ones with unfavorable factors.

Ibrutinib, Fludarabine, Cyclophosphamide and Obinutuzumab (iFCG) for Firstline Treatment of Patients with CLL with Mutated IGHV and without Del(17p)/ TP53 Mutation: Six-Year Follow-up Analyses

Background Patients (pts) with IGHV-mutated ( IGHV-M) CLL have favorable long-term outcomes after receiving first-line FCR (fludarabine, cyclophosphamide and rituximab). We designed an investigator-initiated, phase II trial with ibrutinib, fludarabine, cyclophosphamide, and obinutuzumab (iFCG) for previously untreated pts with IGHV-M CLL (NCT02629809), and we report here an updated analysis with a median follow-up of 72 months. Methods Inclusion criteria included diagnosis of previously untreated CLL/SLL needing treatment per iwCLL criteria, age ≥18, IGHV-M, absence of both del(17p) and TP53 mutation. Pts received 3 courses of iFCG. Pts achieving CR/CRi with undetectable MRD (U-MRD) in bone marrow (BM) (4-color flow-cytometry, sensitivity 10 -4) after 3 courses of iFCG received ibrutinib with obinutuzumab (iG) for 3 cycles, followed by ibrutinib monotherapy for 6 months. All other pts received iG for 9 cycles (C4-12). Pts with U-MRD (CR/CRi or PR) at end of Cycle 12 stopped all therapy, including ibrutinib. Response assessment was per 2008 iwCLL criteria with BM and CT scans every 3 months during the first year. After completion of all therapy, pts were followed by clinical examination, blood counts and peripheral blood MRD every 6 months. Results Between March 2016 and August 2018, 45 pts initiated treatment. Data cutoff was July 15, 2023. Baseline characteristics are shown in Table 1. All pts per study inclusion criterion had IGHV-M; however, 1 enrolled pt was later reclassified as IGHV-unmutated. A total of 69% pts had del(13q). After three cycles of iFCG, 39/45 (87%) pts achieved marrow U-MRD. Responses improved with continued therapy with 40/45 (89%) and 41/45 (91%) achieving marrow U-MRD after Cycles 6 and 12, respectively. Overall, 44/45 (98%) pts achieved marrow U-MRD as best response at any time during the study. Median follow-up duration is 72 months. 41/45 pts completed 12 cycles of treatment (4 pts came off study prior to Cycle 12). All 41 pts achieved marrow U-MRD and per protocol, discontinued ibrutinib. After a median follow-up of 61 mos post-discontinuing ibrutinib, 8 pts had MRD recurrence (defined as 2 consecutive values of ≥0.01% in peripheral blood by flow cytometry) at a median of 32 mos (range, 20-67 mos) after stopping all therapy. Of the 8 pts with MRD recurrence, 2 pts had clinical relapse (described below); remaining 6 pts are being monitored with no clinical progression or active therapy. The 6-year PFS and OS are 92.2% (95% CI= 77.7-97.4) and 97.7% (95% CI= 84.9-99.6), respectively. Two pts had clinical progression: one pt had IGHV 3-21; MRD recurred 28 mos after discontinuing ibrutinib, with clinical relapse 59 mos after discontinuing ibrutinib; this pt is now in remission with venetoclax-based therapy; the second pt with clinical relapse had IGHV-unmutated CLL, MRD recurred 24 mos after discontinuing ibrutinib, with clinical relapse 48 mos after discontinuing ibrutinib; this pt has not yet required therapy for relapse. No pt had progression to Richter transformation. One pt developed therapy-related myelodysplastic syndrome; this pt is being monitored for 58+ months without any active therapy for MDS with normal blood counts. One pt died from congestive heart failure during month 9 of the study. Conclusions iFCG regimen with only three cycles of combination chemotherapy achieves U-MRD rates of 98% in bone marrow on an intent-to-treat analysis and a 6-year PFS of 92% in IGHV-M CLL. These results are favorable compared to the 5-year PFS of approximately 65% with FCR (CLL10 trial) for the same genomic subgroup. Additionally, these results also appear favorable to the current targeted therapy regimens (such as BTKi, BCL2i+CD20 antibody) for IGHV-M CLL. With the caveat that the role of chemoimmunotherapy in CLL has significantly declined, the iFCG regimen provides for a very high rate of durable remissions among a chemo-sensitive subgroup of pts with CLL.

Mass Spectrometry-Based Assessment of M-Protein in Peripheral Blood during Maintenance Therapy in Multiple Myeloma (MM) in the Phase III ATLAS Trial

Introduction Minimal residual disease (MRD) assessment in bone marrow (BM) has emerged as one of the strongest prognostic factors in MM. Mass spectrometry (MS), capable of detecting MM-derived monoclonal proteins in peripheral blood with high sensitivity, has the potential to complement standard methods. While its role in evaluating residual disease and its prognostic performance compared to routine MRD assessments is not yet established, other unanswered questions remain: (1) What is the role of MS in response assessment for patients without a high disease burden baseline sample? (2) What is the optimal timing of MS assessment, considering the long half-life of immunoglobulins? Methods Stored serum samples collected at different timepoints [screening, cycle 6 (C6), C12, C18, C24, C36] from patients treated in the ATLAS trial, were analyzed using the EXENT® Immunoglobulin isotypes (GAM) assay (EXENT® Solution, in development by The Binding Site, part of Thermo Fisher Scientific), which utilizes MALDI-TOF MS. ATLAS is an ongoing phase 3 trial that randomized 180 patients with newly diagnosed MM after autologous stem cell transplantation (ASCT) to maintenance therapy with carfilzomib, lenalidomide, and dexamethasone (KRd) or lenalidomide alone (R). In the KRd arm, patients with standard-risk cytogenetics who achieved MRD-negativity after cycle 6 de-escalated therapy to receive R, from C9. No baseline diagnostic samples were available, and samples were not available for every patient at every timepoint. A sample was called positive by MS when the EXENT® solution confirmed the presence of an M protein, matching the known (diagnostic) isotype. BM MRD was assessed at the same timepoints using multicolor flow cytometry (MFC) with a limit of detection (LoD) of 10 -5 and next-generation sequencing (NGS, clonoSEQ, Adaptive, LoD 10 -6). Progression-free survival (PFS) was analyzed using the Kaplan-Meier method, with log-rank test for comparisons between groups. The data cutoff (31-Dec-2021) was the same as was used in the ATLAS publication by Dytfeld et al. Lancet Oncology 2023. Results 585 samples from 138 patients were analyzed by MS. There were 349 paired BM MRD results by NGS; patients with MRD 10 -5 were considered MRD(+). The overall agreement between the two methods equaled 70%, with a comparable number of patients being MS+/NGS- (56/349, 16%) and MS-/NGS+ (50/349, 14%). The agreement at screening was 61%, but it improved at further timepoints and reached the highest level at C18 (74%). For BM MFC, there were 499 paired samples. There was 67% agreement, and the discrepancy was driven mostly by MS+/MFC- patients (125/499, 25%), whereas MS-/MFC+ was less frequent (40/499, 8%). The agreement was lowest at screening (60%), similarly to the NGS-based assessment, and reached the highest level at C18 (73%). Based on these findings, we concluded that C18 may be the optimal timepoint to assess prognostic role of MS results. Using the landmark method, MS(-) following C18 was associated with superior PFS compared to MS(+) [HR=0.39 (95% CI: 0.17-0.91), p=0.025; Figure 1]. MFC [HR=0.13 (0.04-0.35), p=0.0002], and NGS [HR=0.15 (0.03-0.63), p=0.003] statuses were also associated with PFS using this landmark method. Although small numbers of patients preclude definitive conclusions, we observed a similar effect size in outcomes among NGS(-)/MS(-) vs NGS(-)/MS(+) patients [HR=0.14 (0.01-1.58), p=0.06] and MFC(-)/MS(-) vs MFC(-)/MS(+) [HR=0.40 (0.13-1.27), p=0.11], both favoring BM MRD(-) with concurrent MS(-). Out of the 45 patients who were initially MS(+) and subsequently converted to MS(-), 23 (51%) occurred following C12 or later. Patients who converted from MS(+) to MS(-) had similar PFS to those with sustained MS(-) throughout the analyzed period [HR=0.74 (0.32-1.68), p=0.47; Figure 2], with the majority of PFS events in the converted group occurring during first 18 months of observation. Conclusions MS-based disease assessment in the post-ASCT setting is feasible in many cases, if information on the original MM clone is available by traditional methods. Our results suggest that the optimal timepoint for such evaluation can be as long as 18 months after ASCT. The EXENT® assay may be complementary to BM-based techniques for MRD assessment, allowing for more accurate prognostication when used in combination. Further studies are needed to confirm its exact timing and role in the disease evaluation algorithms.

Combined Ibrutinib and Venetoclax for First-Line Treatment of Patients with Chronic Lymphocytic Leukemia (CLL): 5-Year Follow-up Data

Background: Ibrutinib (IBR) and venetoclax (VEN) combination is an effective therapy for patients (pts) with CLL. We previously reported results of the first-line cohort of a phase II trial of combined IBR and VEN for high-risk pts with CLL (Jain, NEJM 2019, JAMA Oncology 2021). Here we report updated data for 120 pts (80 pts in the original published cohort and 40 pts in an expansion cohort) with a median follow-up of 61.5 months. Methods: Pts with previously untreated CLL meeting IWCLL treatment criteria were enrolled. All pts had at least one high-risk feature: del(17p), mutated TP53, del(11q), unmutated IGHV, or age ≥65 years. Pts received IBR 420 mg daily for 3 cycles followed by addition of VEN (weekly dose-escalation to 400mg daily). Combined therapy was given for 24 cycles (28 days/cycle). Pts with bone marrow (BM) undetectable MRD (U-MRD) (flow cytometry; sensitivity 10 -4) at 24 cycles of combined therapy discontinued both VEN and IBR; MRD+ pts continued IBR. A trial amendment allowed an additional 12 cycles of combined VEN and IBR for pts who remained BM MRD+ after Cycle 24. Response assessments included BM and CT studies (2008 IWCLL criteria). U-MRD was defined as <0.01%; low MRD+ 0.01% to <1%; high MRD+ ≥1%. Progression-free survival (PFS) was assessed as the time from the start of study drug to CLL progression, Richter transformation, or death from any cause. Blood MRD was monitored every 6 months after active therapy. Results: Between August 2016 and February 2019, a total of 120 pts were enrolled. Median age was 64.5 years (range, 26-88 years). 86% had IGHV-unmutated CLL. 23% had del(17p)/ TP53 mutation. The median follow-up is 61.5 months. Six pts came off study during 1 st 3 cycles of IBR monotherapy; 114 pts initiated VEN. After 12 cycles of the combination, 62/120 (52%) achieved BM U-MRD remission; 43/120 (36%) were BM MRD-positive (low MRD+, n=35; high MRD+, n=8). After 24 cycles of the combination, 77/120 (64%) achieved BM U-MRD remission; 24/120 (20%) were BM MRD+ (low MRD+, n=23; high MRD+, n=1). Overall, 86/120 (72%) achieved BM U-MRD as the best response. One pt had DLBCL transformation and 1 pt had CLL progression during the first 2 year of therapy (details below). The 5-year PFS is 90.1% and 5-year OS is 95.6% (Figure 1). The 5-year PFS for pts with del(17p)/ TP53 mutation (n=27) is 86.1%. Of the 77 pts who were BM U-MRD at the end of cycle 24 of the combination, 73 discontinued all therapy, 4 pts continued IBR per treating physician discretion. Among these 77 pts, with a median follow-up of 40 months post Cycle 24, 22 pts had recurrence of blood MRD (defined as MRD ≥0.01% in 2 consecutive visits). Of the 22 pts with MRD recurrence, 5 pt had CLL progression at a median of 18 months (range, 6-30 months) from MRD recurrence (details below); 16 are being monitored without any active therapy for CLL and without clinical disease progression; 1 pt died from mesothelioma. Among the 55 pts who remain in blood U-MRD remission, 53 remain in long-term follow-up in U-MRD remission; 1 pt had B-PLL transformation and 1 patient died (found unresponsive at home; was off therapy for 2 years). There were 24 pts who were BM MRD+ at the end of cycle 24 of the combination (low MRD+, n=23; high MRD+, n=1). The only pt with high-MRD+ at end of cycle 24 was noted to have Richter transformation at that time. The remaining 23 pts (all low MRD+ in BM, range 0.01-0.95%) continued IBR monotherapy. With a trial amendment, MRD+ pts after Cycle 24 could get 12 additional cycles of VEN; 18/23 pts have resumed VEN. 11/18 (61%) pts achieved U-MRD remission during the third year of combined therapy. Only 2/23 pts are still receiving IBR (remaining pts have d/c IBR; all pts have d/c venetoclax); none of these 23 pts had clinical relapse. A total of 6 pts had CLL progression (1 during the first 2 yr of therapy; remaining 5 during off-therapy phase). 3/6 had evaluation of BTK, PLGG2 and BCL2 mutations at the time of relapse and none were detected. 5 pts have started subsequent therapy (acalabrutinib, n=4; ibrutinib, n=1; all are clinically responding); 1 pt has not yet started therapy. Conclusions: We report long term follow-up of combined IBR and VEN in first-line CLL (n=120) with a 5-year PFS of 90.1%. The 5-year PFS for pts with del(17p)/ TP53 mutation is 86.1%. Retreatment with BTK inhibitor appears effective for pts with disease relapse.

Monitoring of Systemic Light-Chain Amyloidosis Patients Using Mass Spectrometry (M-inSight) in Serum

Introduction: Systemic light-chain amyloidosis (AL) is a rare disorder characterized by extracellular deposition of monoclonal light-chain immunoglobulins forming insoluble aggregates in different organs. Kidney, heart and liver are principal organs affected by the disease inducing dysfunctions and failures. In this disease, even a low level of circulating light chain can cause significant damages, making challenging the measure of disease burden via peripheral blood. Although a bone marrow aspiration is required to confirm the diagnosis, the evolution of the disease is usually monitored using free light chains dosage, serum and urine electrophoresis, as well as immunofixation. However, these techniques have demonstrated some limitations in terms of sensitivity. Sebia had recently introduced M-inSight TM, a novel, ultra-sensitive and non-invasive assay for monitoring low level disease on blood using targeted mass spectrometry. In this pilot study, M-inSight TM technology is employed to assess the use of mass spectrometry to monitor AL patients. Methods: 14 AL patients were selected to assess the use of M-InSight to detect and quantify AL light chain. 8/14 patients were selected from the AMYDARA study (NCT02816476), consisting in refractory patients treated with Daratumumab. Serum free light-chain assay (Freelite TM), immunofixation on serum/urine as well as bone marrow collection for DNA (ClonoSeq) and RNA (RACE-RepSeq) immunoglobulin next generation sequencing were used to monitor the disease at baseline and end of treatment (EOT) and compared to M-inSight TM. Additionally, 6/14 multicenter patients with normal free light chain level at diagnosis were selected to evaluate the sensitivity of M-InSight. Total mRNA was extracted from BM samples, retrotranscribed to cDNA and then used for immunoglobulin repertoire high-throughput sequencing assay (RACE-RepSeq). cDNA assembly pipeline using IMGT/HighV-QUEST and Vidjil software were used to construct clonotypes and to identify clonal molecular fingerprints and finally their clonotypic peptides for M-InSight analysis. This technology consists of sequence the AL light chain from serum sample and choose clonotypic peptides from the hypervariable regions which then tracked down in the follow-up sample. Results Clonotypic peptides were identified in all eight patients from the baseline sample, which were then confirmed by mass spectrometry. Out of the 8 AMYDARA patients, 5/8 patients achieved very good partial response (VGPR), 2/8 achieved partial response (PR) and 1/8 resulted in complete response (CR). 6 patients had a decrease of the dFLC ratio measure with Freelite TM of 80% or more. 6 out of these 8 patients had MS data highly concordant with that of the serum free light-chain assay. 2 patients had a strong decrease in dFLC while MS measurements were stable or increased. However, detection of the clonotype using RACE-RepSeqand Clonoseq remained elevated, which was more in line with MS than Freelite TM. All patients with normalization of their dFLC were still detected using M-inSight, even those reaching MRD negativity (1 patient) or low number of cells (~10-5, 2 patients) by ClonoSeq. These results were consistent with the RACE-RepSeq which detected the light chain clonotypes in all patients at EOT. Clonotypic peptides using M-InSight were also detected in all 7 patients with normal free light chain at diagnosis. However, in one bi-clonal patient, peptides from only one of both chains were detected, suggesting that only one clone was secreting light chain. Conclusion The goal of this study was to evaluate the M-InSight technique to monitor the evolution of systemic AL amyloidosis in blood samples. The results showed a high concordance with bone marrow MRD measurement and a higher sensitivity than dFLC to monitor the disease. This study shows that MRD monitoring on blood is feasible, using an ultra-sensitive MS technique, avoiding invasive bone-marrow aspirate. M-inSight can track low level AL disease.

Outcomes after CAR T Cells in Multiple Myeloma Patients with Extramedullary and Paramedullary Disease

Background: Extramedullary disease (EMD) is a poor prognostic factor for multiple myeloma patients even in the era of novel therapies, while patients with paramedullary disease (PMD) have historically fared better. We sought to characterize EMD and PMD in the peri-CAR T period, assess their effects on outcomes after CAR T, and evaluate the ability of CAR T-cell therapy to clear EMD. Methods: We retrospectively analyzed patients with relapsed/refractory multiple myeloma (RRMM) treated with CAR T-cell therapy in a clinical trial or with a commercially approved product at The Mount Sinai Hospital who had at least 3 months of follow-up. EMD was defined as the presence of soft tissue lesions not contiguous with bone and was quantified by measuring the sum of the product of the two longest perpendicular diameters (SPD) of each lesion. PMD was defined as the presence of soft tissue lesions contiguous with bone. Results: A total of 134 patients received CAR T-cell therapy for RRMM between April 2017 and February 2023 and were followed for a median of 18.6 months, with 59 patients treated with ciltacabtagene autoleucel, 52 with idecabtagene vicleucel, and 23 with other products on clinical trials. Thirty-four patients (25.4%) had EMD at baseline (EMD+), while patients without EMD were further subdivided into those with PMD (PMD-only, 25 patients, 18.7%) and those with neither EMD nor PMD (75 patients, 56.0%). Among patients with measurable EMD, median SPD was 11.15 cm 2 (range 0.25-200.10 cm 2). Patients were heavily pretreated with triple-class refractory status present in 94.1% of EMD+ patients, 96.0% of PMD-only patients, and 74.7% of patients with neither. Compared to patients with neither EMD nor PMD, PMD-only patients had similar PFS (HR 0.98, 95% CI 0.51-1.87) and OS (HR 1.34, 95% CI 0.48-3.76), while EMD+ patients exhibited significantly worse PFS (HR 1.87, 95% CI 1.13-3.09) and OS (HR 3.78, 95% CI 1.81-7.92). Overall response rates (ORR) were 76.5% in EMD+, 92.0% in PMD-only, and 88.0% in patients with neither. Among EMD+ patients, those with the highest tumor burdens (SPD ≥50 cm 2, n = 7) had ORR of 57.1% with no complete responses (3 PD, 3 PR, 1 VGPR). Conversely, EMD+ patients with SPD <50 cm 2 (n = 27) had 81.5% ORR and deeper responses (66.7% complete response). Of the 134 patients, 69 patients relapsed including 34 with EMD at relapse. Among the 34 patients with baseline EMD, 23 (67.6%) relapsed including 21 (61.8%) who relapsed with EMD. EMD was present in its prior location for 13 patients, while EMD cleared in prior locations and was present in new locations for 8 patients. Of 100 patients who had no EMD at baseline, only 13 (13.0%) relapsed with EMD. All patients with bulky EMD (SPD ≥50 cm 2) relapsed with EMD. Among the 34 patients with EMD at relapse, 28 were assessed for MRD status in the bone marrow at the time of relapse, of which 12 (42.9%) remained MRD negative by next generation flow (sensitivity 10 -5). EMD post-BCMA CAR T was biopsied and stained for BCMA in 7 relapsing patients, of which 6 were BCMA positive and 1 was BCMA negative. Conclusion: EMD is a well-recognized poor prognostic factor in multiple myeloma. In our single-center retrospective analysis, the presence of EMD but not PMD was associated with significantly worse PFS and OS following CAR T-cell therapy. EMD+ patients with SPD <50 cm 2 experienced high response rates and deep responses following CAR T-cell therapy (with two-thirds of patients clearing EMD), while patients with the highest extramedullary tumor burdens (SPD ≥50 cm 2) did not. This shows the ability of CAR T-cell therapy to benefit patients in this high-risk group when extramedullary tumor burden is lower. We contend that controlling extramedullary sites of disease prior to CAR T-cell therapy with optimal bridging chemotherapy and/or radiation therapy may be an effective strategy for improving outcomes. Half of patients relapsing after CAR T-cell therapy had EMD, and the majority of patients with baseline EMD ultimately relapsed with EMD despite having been radiographically EMD negative following CAR T treatment. Finally, 42.9% of patients relapsing with EMD after CAR T-cell therapy remained MRD negative in the marrow, showing bone marrow MRD does not adequately represent overall disease control post-CAR T.

OA-14 Persistent bone marrow and imaging MRD negativity may guide the duration of lenalidomide maintenance following ASCT in patients with multiple myeloma

OA-14 Persistent bone marrow and imaging MRD negativity may guide the duration of lenalidomide maintenance following ASCT in patients with multiple myeloma

529 - Prognostic Value of Month 1 Bone Marrow and PET MRD Status in CAR-T Therapy for Myeloma

529 - Prognostic Value of Month 1 Bone Marrow and PET MRD Status in CAR-T Therapy for Myeloma

Preliminary Results of the Filo Phase 2 Trial for Untreated Fit Patients with Intermediate Risk Chronic Lymphocytic Leukemia Comparing Ibrutinib Plus Venetoclax (IV) Versus FCR: Results of the Month 15 MRD Evaluation

With the emergence of targeted therapies, defining the best strategy for the treatment of previously untreated CLL patients remains challenging. The aim of this phase 2 study was to compare the efficacy in first line of combined ibrutinib and venetoclax (IV) to the standard FCR regimen in fit patients with CLL of intermediate risk defined by either unmutated IGHV status, 11q deletion or complex karyotype in the absence of TP53 alteration. As previously reported (Michallet et al., Blood 2021; 138 (suppl 1):641), 120 patients were randomized 1:1 between two treatment arms, ie FCR 6 cycles or IV. After a lead-in phase of ibrutinib as a single agent from month (M)1 to M3, the total duration of treatment with the IV combined treatment was based on the response achieved at M9; if bone marrow (BM) MRD was < 0.01% using flow cytometry, the treatment was continued for 6 additional months until M15 and then stopped; if BM MRD at M9 was ≥ 0.01%, the treatment with IV was continued for 18 additional months until M27. PB MRD evaluation was performed every 6 months, whereas BM MRD was performed at M9 and M27.The primary endpoint was the percentage of patients with BM MRD < 0.01% at M27 in both arms. We present herein safety data and the preliminary results of the PB MRD evaluation at M15 . These 120 patients were enrolled from September 2019 to February 2021. The median age was 59 [34-72] and 61 [34-74] years in the FCR and IV arms, respectively. The characteristics of patients were well balanced between the 2 arms in terms of gender (male 72% FCR, 74% IV), PS ECOG 0-1 (59% FCR, 68% IV) and Binet stage (A, B and C 15%, 64%, 21% for FCR ; 8.5%, 59% and 32% for IV). 11q deletion was found in 20% and 24% of cases in the FCR and IV arms, respectively and all patients but one had unmutated IGHV. At the time of data cut-off for this interim analysis, the median follow-up was 24.8 [16.7 - 33.6] months. Sixty-three serious adverse events (SAE) were reported so far, 33 in the FCR arm and 30 in the IV arm. In the FCR arm, the most frequent SAE were tumour lysis syndrome (N=3), infections (N=12 including 4 COVID19 infections), febrile neutropenia (N=5) and secondary malignancies (N=2, including 1 myelodysplastic syndrome and 1 acute myeloid leukemia). In the IV arm, the most frequently reported SAE were tumour lysis syndrome (N=5), infections (N=8 including 4 COVID19 infections), cardiovascular events (N=7), acute renal failure (N=2) and secondary malignancies (N=2, including 1 colorectal cancer and 1 skin basal cell carcinoma). Three grade 5 adverse events were reported consisting in 1 acute myeloid leukemia in the FCR arm and 2 sudden death in the IV arm. No patient died because of COVID19 in the study. At M15, in intention to treat, in the FCR arm, 61.3 % of patients had peripherical blood MRD <0.01%, whereas MRD was ≥ 0.01% without clinical progression in 19.4% of patients and 6.5% of patients had experienced clinical progression. In the IV arm, PB MRD < 0.01% was reached in 63.8% of cases, MRD was ≥ 0.01% in 29.4% of patients and clinical progression was reported in 1.7% of patients (figure 1). In the FCR arm, 1 patient with MRD ≥ 0.01% at M9 converted to MRD < 0.01% at M15 while 2 patients had a signigicant increase of their PB MRD level from <0.01 to ≥ 0.01%. Conversely, in the IV arm, 12 patients converted from MRD ≥ 0.01% at M9 to MRD < 0.01% at M15 while 2 patients increased their PB MRD level from <0.01 to ≥ 0.01%. The two later patients had prematurely discontinued treatment before M15 evaluation. In conclusion, these preliminary results show an increase in PB MRD < 0.01% rates between M9 and M15 in the IV arm, with rates similar to those of the FCR arm at M15. However, toxicity remains significant. The primary enpoint analysis at M27 will be of great interest to try to determine the best strategy. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Combined Ibrutinib and Venetoclax for First-Line Treatment of Patients with Chronic Lymphocytic Leukemia (CLL): 4-Year Follow-up Data

Background: Ibrutinib (IBR) and venetoclax (VEN) combination is an effective therapy for patients (pts) with CLL. We previously reported results of the first-line cohort of a phase II trial of combined IBR and VEN for high-risk pts with CLL (Jain, NEJM 2019, JAMA Oncology 2021). Here we report updated data for 120 pts (80 pts in the original published cohort and 40 pts in an expansion cohort) with a median follow-up of 4 years. Methods: Pts with previously untreated CLL meeting IWCLL treatment criteria were enrolled. All pts had at least one high-risk feature: del(17p), mutated TP53, del(11q), unmutated IGHV, or age ≥65 years. Pts received IBR 420 mg daily for 3 cycles followed by addition of VEN (weekly dose-escalation to 400mg daily). Combined therapy was given for 24 cycles (28 days/cycle). Pts with bone marrow (BM) undetectable MRD (U-MRD) (flow cytometry; sensitivity 10-4) at 24 cycles of combined therapy discontinued both VEN and IBR; MRD+ pts continued IBR. A trial amendment allowed an additional 12 cycles of combined VEN and IBR for pts who remained BM MRD+ after Cycle 24. Response assessments included BM and CT studies (2008 IWCLL criteria). U-MRD was defined as <0.01%; low MRD+ 0.01% to <1%; high MRD+ ≥1%. Progression-free survival (PFS) was assessed as the time from the start of study drug to CLL progression, Richter transformation, or death from any cause. Blood MRD was monitored every 6 months after active therapy. Results: Between August 2016 and February 2019, a total of 120 pts were enrolled. Baseline characteristics are shown in Table 1. The median follow-up is 48.8 months. Six pts came off study during 1st 3 cycles of IBR monotherapy; 114 pts initiated VEN. After 12 cycles of the combination, 62/120 (52%) achieved BM U-MRD remission; 43/120 (36%) were BM MRD-positive (low MRD+, n=35; high MRD+, n=8). After 24 cycles of the combination, 77/120 (64%) achieved BM U-MRD remission; 24/120 (20%) were BM MRD+ (low MRD+, n=23; high MRD+, n=1). Overall, 86/120 (72%) achieved BM U-MRD as the best response. We evaluated baseline pt and disease characteristics (age, gender, IGHV mutation status, CLL FISH panel, complex karyotype, TP53 mutation, del(17p)/TP53 mutation) and rate of bone marrow U-MRD at 6 months, 12 months and at any time during the combined IBR+VEN treatment. At 6 months of combined therapy, presence of TP53 mutation was associated with a lower rate of bone marrow U-MRD (p=0.03); however, none of the aforementioned characteristics, including TP53 mutation were associated with marrow U-MRD responses at 12 months or with best MRD response at any time during the combined therapy. There was a trend towards lower U-MRD rate among pts with mutated IGHV vs. unmutated IGHV at 12 month (p=0.09) and as best response (p=0.09). The 4-year PFS is 94.5% (95% CI, 90.3%-98.9%) and 4-year OS is 96.6% (95% CI, 93.3%-99.9%). The 4-year PFS by TP53 aberrant status is shown in Figure 1. The 4-year PFS for pts with del(17p)/TP53 mutation (n=27) is 90.9% and for pts without del(17p)/TP53 mutation (n=93) is 95.5%. None of the aforementioned pt/disease characteristics were associated with PFS. Of the 77 pts who were BM U-MRD at the end of cycle 24 of the combination, 73 discontinued all therapy, 4 pts continued IBR per treating physician discretion. Among these 77 pts, with a median time of 23.9 months post Cycle 24, 11 pts had recurrence of blood MRD (defined as MRD ≥0.01% in 2 consecutive visits). Of the 11 pts with MRD recurrence, 10 are being monitored without any active therapy for CLL and without clinical disease progression; 1 pt had disease progression after 22 months of treatment-free interval and is currently receiving acalabrutinib. There were 24 pts who were BM MRD+ at the end of cycle 24 of the combination (low MRD+, n=23; high MRD+, n=1). The only pt with high-MRD+ at end of cycle 24 was noted to have Richter transformation at that time. The remaining 23 pts (all low MRD+ in BM, range 0.01-0.95%) continued IBR monotherapy. With a recent trial amendment, MRD+ pts after Cycle 24 could get 12 additional cycles of VEN; 18/23 pts have resumed VEN. 11/18 (61%) pts achieved U-MRD remission during the third year of combined therapy. Conclusions: We report long term follow-up of combined IBR and VEN in first-line CLL (n=120) with a 4-year PFS of 94.5%. MRD responses and PFS were independent of baseline pt/disease characteristics. Continuation of combined therapy among marrow MRD+ pts during the second and the third year led to achievement of U-MRD in a subset of pts. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

ALL-REZ BFM 2002 Is Associated with Improved Outcome as Compared to ALL-R3 Strategy in Children with Standard Risk Isolated CNS Relapse of Acute Lymphoblastic Leukemia, while Maintaining Comparable Efficacy in Patients with Bone Marrow Relapse. Results of the Multi-National, Multi-Center Trial IntReALL SR 2010

Background: Around 15% of children with acute lymphoblastic leukemia (ALL) experience disease relapse. The prognosis of these patients largely depends on the site of recurrence, time to relapse and leukemia immunophenotype. The ALL-REZ BFM 2002 and the ALL R3 trials have proved to be effective in previous trials. The IntReALL SR 2010 trial, conducted under the umbrella of the I-BFM SG, aimed at investigating feasibility, toxicity and efficacy of both treatment strategies in a large multi-national, multi-center prospective randomized trial. Methods: Patients with a first standard-risk (SR) ALL relapse aged 1 - 17 years were recruited to the trial from 23/Oct/2014 to 31/Jul/2020 in 17 countries (210 centers). SR relapse criteria were: late (≥ 6 months after end of initial therapy) isolated bone marrow (BM) relapse, late or early (< 6 months after end of initial therapy and ≥ 18 months after initial diagnosis) combined BCP-ALL BM relapse, any late/early isolated extramedullary (IEM) relapse. They were randomized at a 1:1 rate to receive either arm A (ALL-REZ BFM 2002) or B (ALL R3). During consolidation, patients were randomized to receive the CD22-directed monoclonal antibody epratuzumab in addition to backbone chemotherapy. Results of this 2nd randomization will be communicated separately. Patients with late BM relapse were allocated to consolidation and maintenance chemotherapy or to allogeneic hematopoietic stem-cell transplantation (HSCT), depending on their minimal residual disease (MRD, cut-off arm A 10e-3 and arm B 10e-4) assessed after induction therapy. Patients with early either combined BM or IEM relapse were allocated to receive allogeneic HSCT. Results: Overall, 620 patients were randomized to receive arm A (n=304) or Arm B (n=316). Patient's characteristics were equally distributed among both groups (table 1). Induction death, 2nd remission rate, death in remission (5-years cumulative incidence (CI) 4.1 vs 7.4%, p=0.10), and subsequent relapse rates by arm A and B (CI 23.8 vs 22.8, p=0.80) did not differ between both groups. The MRD response rate with < 10e-4 post induction was significantly higher in Arm B (p=0.015), but not significantly different based on the arm specific cut-off, leading to comparable rates of allogeneic HSCT. The probability of 5-years event-free survival (pEFS) with arm A versus arm B was 70.2±3.1 SE versus 68.5±3.1 (p=0.61, figure 1) and that of overall survival (pOS) was 86.7±2.3 versus 87.1±2.0 (p=0.8). Subgroup analyses revealed a significantly higher pEFS in patients with isolated CNS relapse when treated with arm A (81.6±6.3, n=40) compared to arm B (43.3±8.3, n=45, p=0.001), whereas in patients with BM involvement or those with non-CNS IEM relapse, no significant difference was found (p=0.41). However, patients with isolated BM relapse experienced a higher CI of subsequent relapse with arm A (12.5±2.1, n=146) as compared to arm B (6.5±1.6, n=153, p=0.008). Patients with late BM relapse and MRD poor response after induction had comparable pDFS (arm A 65.8±6.4, n=74; arm B 68.8±6.2, n=75; p=0.71), which also did not differ from that of patients with MRD good response (arm A 67.7±5.6, n=100; arm B 68.9±5.6, n=113; p=0.77). Patients with late IEM relapse achieved a pEFS of 86.7±4.6 whereas those with early relapse and HSCT indication achieved a pEFS 61.8±5.4 (p=0.0004). Rates of reported severe adverse events (SAEs) per treatment phase did not differ between arms except nervous system disorders occurring more frequently in arm A (p=0.03, table 1). Conclusion: Both arm A and B were effective in this large multi-national trial. EFS and OS probabilities compare favorably to results recently published by other cooperative groups. In particular, the outcome of patients with early IEM relapse or with late BM relapse and MRD poor response is encouraging confirming the benefit of allo HSCT in these subgroups. Due to superior outcome of isolated CNS relapse with arm A, patients without BM involvement will receive that arm as backbone in future trials. Since arm B showed a better MRD response rate after induction and a lower relapse rate in patients with BM relapse, it will be implemented as backbone for future trials in patients with BM involvement. Toxicity (TRM and SAE rates) is substantial in both arms demonstrating the urgent medical need of replacing toxic chemotherapy elements with equally effective, but less toxic targeted immunotherapy strategies in future trials. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Phase 1 Trial of AUC-Targeted Melphalan in Myeloma Patients Undergoing Autologous Transplant (The MyMel Study)

Standard 200 mg/m2 high dose melphalan (HDM) yields a 500% variation in plasma melphalan exposure, i.e. area under the curve (AUC), leading to unpredictable DNA damage and widely variable clinical responses. Strategies to predict melphalan AUC have been unsuccessful given population PK models (Nath, Br J Clin Pharmacol 2010 & Cho Clin Pharmacol Ther 2017) are ineffective on an individual patient level and only explain ~20% of the variability observed, and test dose predictions have failed to accurately represent melphalan AUC for doses >100 mg/m2. PK directed dose adjustment of HDM would require a 24-hour turnaround for sample collection, shipping, processing and data analysis. Previously we described methods for measuring melphalan PK after the Day -2 HDM dose, allowing for real-time dose adjustments (Sweiss, Br J Clin Pharmacol 2020). Here, we set out to perform the first phase 1 study of AUC-targeted HDM in ASCT (NCT04483206). This multicenter phase 1 trial (Fig 1) is designed to test 7 AUC ranges (13-21 mg*h/L) to determine the maximum tolerated systemic exposure (MTSE). The feasibility portion focuses on the first 2 AUCs (phase A, n=20) in patients with ≥2L therapy, where we measure accuracy of achieving target AUCs of 13.5 and 14.5 mg∗h/L, respectively. Patients receive HDM 100 mg/m2 on day -3 with PK measurement and subsequent dose-adjustment on day -1 to achieve the total target AUC. 7 blood samples are drawn, processed and shipped frozen for LC-MS/MS analysis. PK parameter estimations are determined from noncompartmental analysis (NCA) and per FDA guidance used to adjust doses. Nonlinear mixed effects modeling (NONMEM) is performed in parallel to compare PK estimations. Using observed first-dose HDM clearance (Clobs) from NCA and assuming that Cl is consistent between doses, linear dose-proportional adjustments are performed to achieve the target AUC0-inf. After a planned FDA review of these cohorts, we will begin to dose escalate to determine the MTSE with up to 5 AUC levels (15.5-19.5 mg∗h/L). Bone marrow (BM) MRD status will be assessed at Day 90 as part of the Phase B primary objective. Correlatives include measuring DNA damage in circulating PBMCs post-HDM to correlate with AUC, piloting a DNA fiber combing assay on primary MM cells from patient BM samples to quantify DNA replicative stress, and assessing PROs using NCI PRO-CTCAE v.1.0. We have enrolled 8 patients into the first AUC cohort with 110 blood samples collected. Median age was 69 (56-75) years, with 7 (87.5%) males, and 4 (50%) Blacks. The median day -3 HDM Clobs and AUC0-inf were 22.05 (16.3-38.2) L/hr and 9.53 (6.97-11.82) mg∗h/L, respectively. All shipped blood samples were received in suitable frozen condition, and in 7 (87.5%) of 8 patients, LC-MS/MS run with NCA estimation and dose reporting was done within 12 hours of receiving samples. One patient whose samples were delayed from shipping had the dose reported on day-1 resulting in 5 of 7 day-1 samples collected. Covariates of HDM PK (i.e., FFM, hematocrit) were entered into our developed PK model to further enrich our data prediction. All 8 day -1 doses were adjusted, with a resulting median total BSA-based HDM dose of 139.6 (110.93-192.6) mg/m2. After adjustment, median day -1 Clobs and AUC0-inf were 24.48 (19.3-35.8) L/hr and 3.84 (1.7-7) mg∗h/L, respectively. For accuracy of dose adjustment, 107 (97.3%) samples were evaluable for PK parameter estimation, with 3 concentrations excluded (n=3 patients). One subject whose last 2 day -1 samples were not collected was removed from analysis as it resulted in 19% AUC extrapolation and 33% variance between day -3 and -1 Cl values. Of 7 patients, 6 (85.7%) achieved the target AUC, with less than 10% variance in Cl between doses. (Fig 2). In the one patient, it was assessed that the day -1 Cl deviated by 24% as a result of prolonged time from drug admixture to completion of infusion leading to drug degradation. Estimated melphalan Cl generated from NCA and NONMEM correlated well (r=0.99). This is the first trial in MM implementing a novel personalized dosing approach using drug exposure as the target to define each cohort. We demonstrate feasibility of real-time PK sampling, shipping, processing, NCA PK parameter estimation, and dose adjustment of HDM. So far we report a high rate of accuracy in achieving the target AUC which we hypothesize will deliver reliable DNA damage to MM cells. Enrollment is active and mature data will be presented at the conference. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Updated Results from a Phase I/II Study of Duvelisib and Venetoclax in Patients with Relapsed or Refractory (R/R) Chronic Lymphocytic Leukemia (CLL) or Richter's Syndrome (RS)

Background While venetoclax (VEN) in combination with rituximab is an effective combination for patients (pts) with R/R CLL, it requires 2 years (yrs) of treatment (tx) and intravenous infusions. Duvelisib (DUV) is an oral PI3K-δ/γ inhibitor (PI3Ki) approved for R/R CLL/SLL after 2 prior therapies, and preclinical data support the potential for synergy both in CLL (Patel et al., 2017) and in RS PDX models (Iannello et al., 2019). This ongoing phase I/II study is investigating an all-oral, MRD-guided, time-limited regimen of DUV + VEN. Here, we report updated outcomes, now with nearly 2 yrs median follow-up. Methods In this ongoing investigator-sponsored trial (NCT03534323), primary endpoints were DLTs, MTD, RP2D (phase 1) and best CR rate (phase 2). Key eligibility criteria for CLL pts: requiring tx by iwCLL criteria, ≥1 prior tx but no prior DUV or VEN, ECOG PS ≤2. For RS pts there was no restriction on # of prior tx, though no VEN was allowed within 1 yr. Pts receive a maximum of 12 cycles of combination DUV + VEN. Tx begins with a 7-day lead-in of DUV 25mg BID, and VEN initiation occurs on day 8. In phase 1, VEN was started at 10mg or 20mg inpatient (inpt) with weekly ramp-up outpatient (outpt) to 50mg, and then to a maximum dose of 100mg, 200mg, or 400mg using a 3+3 design. In phase 2, VEN is initiated at 10mg (outpt) or 20mg (inpt) with weekly ramp-up to 400mg daily. Pts with RS can undergo accelerated VEN ramp-up to 400mg over 5 days (inpt). After 12 cycles, pts with undetectable bone marrow MRD (BM-uMRD) can discontinue tx, with an option to reinitiate VEN at progression, and pts with detectable MRD continue VEN. Assessments: toxicities by CTCAE v5, efficacy by 2008 iwCLL criteria, MRD by central 8-color flow (10-4 sensitivity). Research funding and DUV were provided by Secura Bio. Results As of July 13, 2022, 43 pts were enrolled (n=35 CLL and n=8 RS). Median age: 69 yrs (range 50-79); 70% male. 70% unmutated IGHV. In all patients, 42% were TP53-aberrant (del(17p) or TP53 mut); 9% del(11q); 33% complex karyotype (≥ 3 abnormalities); 23% NOTCH1 mut. Median prior tx: 2 (range 1-6). 42% with prior BTKi tx (all ibrutinib). The RP2D of VEN in combination with DUV was 400mg daily. In the total population of 43 pts, all-grade all-causality heme tox included: neutropenia (64%; 57% Gr3/4), thrombocytopenia (43%; 19% Gr3/4), anemia (33%, 5% Gr3). Notable non-heme tox ≥ 20% included: diarrhea (40%; 7% Gr 3), nausea (40%, 2% Gr3), fatigue (40%, all Gr1/2), hypertension (36%, 7% Gr3), increased alkaline phosphatase (36%, all Gr1/2), headache (26%, all Gr1/2), increased AST/ALT (24%; 7% Gr3), and cough (26%, all Gr1/2). Other notable SAEs ≥ 5%: increased bilirubin (12%, 5% Gr3/4), severe infection (9% Gr3, 1 pt with Gr5 COVID-19 pneumonia). 3 pts had laboratory evidence of tumor lysis syndrome (TLS); 1 pt had clinical TLS with acute kidney injury after the 20 mg VEN dose during ramp-up that fully resolved, and the pt successfully resumed VEN monotherapy. One pt developed a Gr4 gastric perforation while on high-dose steroids to manage diarrhea and discontinued study tx. One pt with RS had Gr5 hepatic failure in the setting of biopsy-proven RS liver involvement. The median number of cycles was 13 (range 1-44). The best ORR in the pts with CLL (n=35) was 69% (43% CR/CRi, 26% PR; Figure 1A). 31% of pts with CLL achieved PB-uMRD and 31% BM-uMRD (Figure 1A). 9/35 pts (26%) achieved CR/CRi with BM-uMRD after 1 year of DUV+VEN and electively discontinued therapy in remission, including 4 pts with del(17p). In the pts with RS (n=8), 3 achieved a CR and 1 achieved a PR. In the 16 CLL pts with TP53-aberrancy, the best ORR was 50% (CR 44%, PR 6%). In 15 CLL pts with prior BTKi tx, the best ORR was 53% (CR/CRi 40%, PR 13%). Eleven pts remain on tx. Reasons for tx discontinuation include: achievement of BM-uMRD (n=12 CLL), electively moving on to allogeneic transplant (n=2 CLL, n=1 RS), PD (n=3 CLL, n=6 RS), unacceptable tox (n=4 CLL, n=1 RS), death due to COVID-19 pneumonia (n=1 CLL). The 2-year PFS for pts with CLL was 78% (95% CI: 63-96; Figure 1B) and the 2-year OS was 90% (95% CI: 80-100). Conclusion A time-limited, all oral regimen DUV + VEN is active in R/R CLL and RS, including in high-risk pts post-BTKi. Immune-mediated and infectious toxicities were observed, but were manageable for most patients. Our data support continued exploration of DUV + VEN in pts with R/R CLL and RS. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Updated Results from a Multicenter, Phase 2 Study of Acalabrutinib, Venetoclax, Obinutuzumab (AVO) in a Population of Previously Untreated Patients with CLL Enriched for High-Risk Disease

Background While venetoclax (V) plus obinutuzumab (O) is a highly effective frontline CLL regimen, outcomes remain suboptimal for high-risk patients (pts). The efficacy of ibrutinib plus VO in such pts is encouraging, but cardiac and infectious toxicities (tox) are common. We hypothesized that a time-limited triplet with the more selective BTKi acalabrutinib (A) would be active and well-tolerated. We previously published results on an initial cohort unrestricted by genetic risk (Davids et al., 2021), and now report on a new cohort with enrollment restricted to high-risk pts, as well as longer follow-up on the initial cohort. Methods Treatment (tx)-naïve pts with CLL with any genetic risk profile were initially enrolled in this investigator-sponsored, phase 2 study (cohort 1), followed by a multi-center expansion restricted to previously untreated pts with TP53-aberrant CLL (cohort 2). A starts at 100 mg BID for 28 days, followed by 2 cycles of AO (O at standard dosing), and V starts on C4D1 at 20 mg, then 50 mg on C4D2, with weekly ramp-up thereafter to 400 mg QD (total 4 week V ramp-up). AVO continues C5-7 (6 total cycles of O), and AV continues C8-15. If the primary endpoint of undetectable bone marrow MRD (BM-uMRD) CR is reached at C16D1, pts can discontinue therapy (tx); all others continue AV through C24, with the option to discontinue if BM-uMRD at C25D1. Assessments: efficacy by 2018 iwCLL criteria, toxicities (tox) by CTCAE v5, MRD by central 8-color flow (10-4 sensitivity) and NGS clonoSEQ (up to 10-6 sensitivity, Adaptive). BH3 profiling work is ongoing, performed as previously described (Ryan J et al., 2016) on peripheral blood (PB) samples after 1 and 3 cycles. Association of BCL-2 dependence with clinical response was compared by an unpaired t-test. Results As of 13 July 2022, 68 pts were enrolled (cohort 1 all-comers: n=37, cohort 2 TP53-aberrant: n=31) in this ongoing study (NCT03580928), with median follow-up of 35 mos (range 2-45). In all 68 pts, median age 63 yrs (range 36-80); 25% ≥70 yrs; 66% male; 60% TP53-aberrant (del(17p) or mut); 24% complex karyotype (≥3 abnormalities); 74% unmutated IGHV. Of the 56 pts evaluable to date at C16D1, 43% (24/56) achieved the primary endpoint BM-uMRD CR. The best ORR is 98% (48% CR, 50% PR). At C16D1, MRD by flow: 86% PB-uMRD, 86% BM-uMRD (Fig 1A). In a subset of 49 pts with available samples, 59% were PB-uMRD by NGS at 10-5 sensitivity (at 10-6, 59% of pts had indeterminate results due to low cell counts). In the 29 pts with TP53-aberrant disease evaluable at C16D1, the best ORR is 100% (52% CR, 48% PR), and 45% (13/29) achieved BM-uMRD CR, MRD by flow: 86% PB-uMRD, 83% BM-uMRD (Fig 1A). There were no differences in response or MRD based on IGHV status. 79% (19/24) of pts in BM-uMRD CR electively discontinued tx after 15 cycles; median time off tx for these pts is 22.9 mos (range 1-30). 2 of the 19 pts who discontinued tx have had MRD only recurrence, and 1 had CLL disease progression; all 3 restarted tx with AV and achieved PR. 3 pts developed Richter's syndrome: 1 with DLBCL after 15 mos on study, and 2 with Hodgkin transformation (one 13 mos after completing study tx and one 12 mos into study tx; both achieved CR to Hodgkin-directed tx). 93% of all pts (63/68) remain progression-free. In all 68 pts, all-grade heme tox included: neutropenia (75%; 37% Gr3/4), thrombocytopenia (73%; 28% Gr3/4), anemia (49%, 3% Gr3). Non-heme tox: headache (78%, 1% Gr3), fatigue (76%, 1% Gr3), bruising (66%, all Gr1/2), nausea (49%, all Gr1/2), diarrhea (40%, 4% Gr3), infusion-related reaction (30%, 4% Gr3), hypertension (27%; 9% Gr3), increased ALT (27%, 1% Gr3), arthralgia (25%, all Gr1), and infection (6% Gr3; 1 case of Gr5 COVID-19 pneumonia). 2.9% (2/68) pts had afib. 14 pts (21%) required dose-reduction of either only A (4%), only V (9%), or both drugs (7%). BH3 profiling is ongoing, and initial data suggest that pts who later went on to achieve CR may have a greater increase in BCL-2 dependence at C4D1 than pts who achieved PR as best response (p=0.05, Fig 1B). Conclusion AVO is a highly active, well-tolerated triplet in a frontline CLL population enriched for high-risk disease, with 83% of TP53-aberrant pts achieving BM-uMRD after 15 mos of tx. Responses are durable, with 93% PFS in all pts at a median follow-up of nearly 3 yrs. Low rates of cardiac and infectious tox were observed. Our data support continued investigation of the MRD-guided, time-limited AVO triplet. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

MiRNA profile at diagnosis predicts treatment outcome in patients with B-chronic lymphocytic leukemia: A FILO study.

ClinicalTrials.gov, identifier NCT01370772.

P-051: Sustained bone marrow and imaging MRD negativity as indicators to discontinue lenalidomide maintenance after ASCT; preliminary results of a single-center prospective cohort study

P-051: Sustained bone marrow and imaging MRD negativity as indicators to discontinue lenalidomide maintenance after ASCT; preliminary results of a single-center prospective cohort study

P674: UPDATED RESULTS OF A PHASE 1B STUDY OF IBRUTINIB (IBR) PLUS OBINUTUZUMAB (OBIN) IN PATIENTS WITH RELAPSED OR REFRACTORY (R/R) CHRONIC LYMPHOCYTIC LEUKEMIA (CLL)

Background: Combination ibr + obin was approved in frontline CLL based on results of iLLUMINATE; however, less data are available on this regimen in R/R CLL. Though active in R/R CLL, ibr monotherapy in RESONATE led to 4-year (yr) PFS/OS of ~45%/65%, leaving room for improvement. We previously reported initial safety and efficacy results of this phase 1b study investigating ibr + obin in R/R CLL (Davids et al., EHA 2020). Here, we report updated results, with median follow-up now of 41.5 months (mos). Aims: To assess longer-term safety and efficacy of ibr + obin in patients (pts) with R/R CLL. Methods: We conducted a phase 1b, investigator-initiated study of ibr + obin in R/R CLL (NCT02537613). The primary objective was to assess safety of 3 different drug sequencing regimens in cycle 1; the main secondary objective was to assess efficacy. Pts were randomized 1:1:1 to either receive obin 1 mo before ibr, ibr 1 mo before obin, or start concomitantly. Both drugs were given at the approved doses and schedule, with 6 total cycles of combination followed by ibr monotherapy until progression or unacceptable toxicity. Notable eligibility criteria: requiring treatment (tx) for R/R CLL/SLL by 2008 iwCLL criteria, ECOG PS ≤2, no prior ibr or obin. Assessments: toxicities by CTCAE v4, efficacy by 2008 iwCLL criteria, MRD by 4-8 color flow (10-4 sensitivity). Serum concentrations of 21 cytokines were assessed pre-tx and after 1 week of combination tx in a representative subset of 27 pts (n=9 per arm) by bead-based multiplex immunoassay (Eve Technologies, Calgary). Results: 52 pts were accrued, and all received ≥1 cycle of combination tx. Median age: 67 yrs (range 33-84); 77% male; median # prior tx: 1 (range 1-6); 25% del(17p) or TP53 mut; 27% del(11q); 50% unmutated IGHV; 27% bulky LAD (nodes ≥5 cm). As of 14 Feb 2022: median follow-up 41.5 mos (range 2.3-73.3). 27 pts (52%) remain on tx. All-grade heme toxicities: thrombocytopenia (88%; 23% Gr3/4), neutropenia (71%; 37% Gr3/4), febrile neutropenia (8%, all Gr3/4), anemia (73%; 8% Gr3). Notable non-heme toxicities: bruising (58%, all Gr1/2), arthralgia (38%, all Gr1/2), diarrhea (37%, all Gr1/2), transaminitis (35%; 4% Gr3), ≥Gr3 infection (17%, all Gr3), and cardiotoxicities: hypertension (46%; 10% Gr3), atrial fibrillation (21%; 10% Gr3). 1 pt had sudden cardiac death after 11 mos on study. 7 pts required ibr dose-reduction due to toxicity. The best ORR is 96%, including 50% CR and 46% PR (Fig. 1A). All 3 pts who previously progressed on venetoclax responded (1 CR, 2 PR). By ITT, 10/52 (19%) achieved a best response of undetectable MRD in bone marrow (BM, 44 pts tested), and 14/52 (27%) in peripheral blood (PB, 34 pts tested). 4-yr PFS and OS are 74% and 93% (Fig. 1B-C), with 3 deaths (n=1 each: sudden death, MDS, Richter’s syndrome). Pts who achieved BM and PB undetectable MRD had a significantly larger decrease in circulating CCL4 (p=0.02) and CXCL13 levels (p=0.01), respectively, comparing baseline to 1 week of combination tx (Fig. 1D). Image:Summary/Conclusion: Ibr + obin is a highly active combination in R/R CLL, achieving 50% CR and 4-yr PFS/OS of 74%/93%, suggesting a potential positive impact of obin (though possibly also reflecting an earlier relapse population than RESONATE). Responses were observed in all 3 pts who had progressed after venetoclax, including 1 CR. With ~3.5 yrs median follow-up, and some pts on tx over 6 yrs, cardiotoxicity was consistent with prior ibr studies, and no new safety concerns have emerged. Our data support continued exploration of combination BTK inhibitor plus obin in R/R CLL.

S149: LONG TERM OUTCOMES OF IFCG REGIMEN FOR FIRSTLINE TREATMENT OF PATIENTS WITH CLL WITH MUTATED IGHV AND WITHOUT DEL(17P)/TP53 MUTATION

Background: Chemoimmunotherapy with FCR has been an effective treatment for patients (pts) with CLL. Pts with mutated IGHV (IGHV-M) have favorable long-term outcomes after receiving FCR. We designed an investigator-initiated, phase 2 trial with ibrutinib, fludarabine, cyclophosphamide, and obinutuzumab (iFCG) for previously untreated pts with IGHV-M CLL (NCT02629809). We report here long-term outcomes with a median follow-up of 56.8 months. Aims: Investigate the role of combined chemoimmunotherapy and targeted therapy in CLL. Methods: Eligibility included age ≥18, IGHV-M, no del(17p)/TP53 mutation. Pts received 3 courses of iFCG. Pts achieving CR/CRi with undetectable MRD (U-MRD) in bone marrow (4-color flow-cytometry, sensitivity 10-4) after 3 courses of iFCG received ibrutinib with obinutuzumab (iG) for 3 cycles, followed by ibrutinib monotherapy for 6 months. All other pts received iG for 9 cycles (C4-12). Pts with marrow U-MRD at end of Cycle 12 stop all therapy. Response assessment was per 2008 iwCLL criteria with BM and CT scans every 3 months during the first year. After completion of all therapy, pts were followed by exam, blood counts and peripheral blood MRD every 6 months. NGS MRD (sensitivity 10-6) was performed in bone marrow in pts with available samples. Results: 45 pts initiated treatment. Median age was 60 [range, 25-71]. 69% had del(13q). After three cycles of iFCG, 39/45 (87%) pts achieved marrow U-MRD. Responses improved with continued therapy with 40/45 (89%) and 41/45 (91%) achieving marrow U-MRD after Cycles 6 and 12, respectively. Overall, 44/45 (98%) pts achieved marrow U-MRD as best response at any time during the study. The 5-year PFS and OS are 97.7% (95% CI 94–100%) and 97.8% (95% CI 94–100%), respectively. No pt had CLL progression or Richter transformation. One pt developed therapy-related MDS; this pt is being monitored for 38+ months without any therapy for MDS with normal blood counts. The sole event noted on both the PFS and OS curve is a pt death from heart failure. 41/45 pts completed 12 cycles of treatment (4 pts came off study prior to C12). All 41 pts achieved marrow U-MRD4 by flow-cytometry and per protocol, all 41 pts discontinued ibrutinib. After a median follow-up of 44.2 mos post-discontinuing ibrutinib, 6 pts had an MRD recurrence (defined as 2 consecutive values of ≥0.01% in peripheral blood by flow cytometry) at a median of 27.2 mos (range, 20.7-49.0 mos) after stopping all therapy. All 6 pts are being monitored with no clinical progression or active therapy; notably, all 6 pts were MRD+ at 10-6 by marrow NGS after the completion of 3 cycles of iFCG and 4/5 (1 missed sample) were MRD+ at 10-6 by marrow NGS after the completion of Cycle 12. Of the 16 pts who were marrow NGS MRD+ at 10-6 after 3 cycles of iFCG, 6/16 had an MRD recurrence in blood in follow-up vs. 0/20 who were NGS MRD negative/indeterminate (p = 0.004). Of the 12 pts who were marrow NGS MRD+ at 10-6 after Cycle 12, 4/12 had an MRD recurrence in blood in follow-up vs. 1/26 who were NGS MRD negative/indeterminate (p = 0.02). Image:Summary/Conclusion: The iFCG regimen, using only 3 cycles of chemotherapy (as opposed to 6 cycles of chemoimmunotherapy) achieves a very high rate of U-MRD in previously-untreated pts with CLL with IGHV-M CLL. No pt had disease progression with a median follow-up of close to 5 years. The 5-year PFS is 97.7%; this is favorable compared to 5-year PFS of ≈65% with FCR (CLL10), ≈70% with ibrutinib (A041202 trial), and 81% with ibrutinib (RESONATE-2) for IGHV-M CLL. Not unexpectedly, MRD recurrence during follow-up correlated with MRD positivity by NGS during therapy.

Impact of bone marrow involvement in patients with peripheral T-cell lymphoma undergoing autologous stem cell transplant.

7550 Background: Nodal-based T-cell lymphomas (PTCL) are treated with induction therapy and consideration for autotransplant (autoSCT) in first remission. The impact of bone marrow (BM) involvement at diagnosis and at autoSCT is unclear. Methods: We performed a retrospective review of consecutive patients with PTCL-NOS, AITL, and ALCL who received autoSCT in first remission at Memorial Sloan Kettering Cancer Center from 1997-2021. For BM involvement at baseline, patients were classified as positive (≥5% by histology), any involvement (by histology and/or at least 1 high-sensitivity [HS] assay, referring to flow or clonal TCR gene rearrangement), or negative (no involvement by histology and at least 1 negative HS assay). Patients with no baseline BM biopsy were excluded. At end of therapy (EOT, after induction but prior to autoSCT), BM involvement was considered positive (≥5% by histology), minimal residual disease positive (MRD+, no histological involvement but at least 1 positive HS assay), and MRD- (no histological involvement and at least 1 negative HS assay). Patients with no EOT BM but negative baseline BM were included as a separate cohort. Patients with no baseline BM and no EOT BM were excluded, as were those with baseline BM involvement and no EOT BM. The Kaplan-Meier method was used to estimate survival and compared using log-rank tests. Results: A total of 135 patients were included. Median follow-up after autoSCT for survivors was 56 months. The 5-year PFS/OS for the entire cohort was 45% and 65%, respectively. By histology, 5-year PFS/OS for PTCL-NOS (N = 27), AITL (N = 78), ALK+ (N = 8) and ALK- (N = 21) ALCL was 36%, 37%, 75%, 74% (p = 0.005), and 51%, 59%, 100%, 85% (p = 0.01). Among those with adequate baseline BM evaluation (N = 98), 31 were positive, 52 had any involvement, and 44 were negative. Five-year PFS and OS in the positive, any involvement, and negative groups was 46%, 42%, 44% (p = 0.82), and 63%, 61%, 74% (p = 0.27). Of those with adequate EOT BM evaluation (N = 72), 1 was positive, 17 were MRD+, and 43 were MRD-; 32 patients had no EOT BM but negative baseline BM. Five-year PFS and OS by the EOT positive, MRD+, MRD-, and no EOT BM but negative baseline groups was 0%, 37%, 45%, 45% (p = 0.86), and 0%, 92%, 59%, 71% (p = 0.39). Of the 17 patients with MRD+ EOT BM, 14 (82%) had AITL. Two-year PFS/OS in the AITL only cohort by EOT BM was 0%, 54%, 48%, 33%, and 0%, 90%, 75%, 72%, for the positive, MRD+, MRD-, and no EOT BM but negative baseline groups (PFS: p = 0.4; OS: p = 0.3). Conclusions: In patients treated with upfront induction and autoSCT in first remission, neither BM involvement at diagnosis nor the presence of MRD at the time of autoSCT resulted in worse survival outcomes compared to those with no BM involvement. For patients with PTCL-NOS, AITL, or ALCL in first remission, baseline BM involvement or pre-autoSCT BM MRD+ should not dissuade use of autoSCT consolidation.