Undetectable Minimal Residual Disease Research Articles

Twice-weekly induction with ixazomib-lenalidomide-dexamethasone (IRd) combination followed by extended IRd consolidation and lenalidomide maintenance in transplant-eligible patients with newly diagnosed multiple myeloma: Results of the phase 2 study IFM2014-03.

Therapeutic strategies for patients with newly diagnosed multiple myeloma (NDMM) have considerably improved during the last 10 years. The IFM2014-03 trial proposed an all-oral triplet induction/consolidation regimen in transplant-eligible NDMM patients, followed by lenalidomide maintenance. Induction consisted of three 21-day cycles of ixazomib, lenalidomide and dexamethasone (IRd), before high-dose Melphalan with transplant followed by eight 28-day cycles of IRd consolidation before 13 cycles of lenalidomide maintenance. Forty-six patients were enrolled and received at least one dose of therapy, and 39 entered the maintenance phase. The primary end-point was stringent complete response after consolidation, and was achieved in nine patients (20.9%, 90% CI 11.4-33.7; p = 0.998). Ten patients (24.4%) had an undetectable minimal residual disease. The overall response rate was 95.7%. The 3-year progression-free survival was 66.3%. No unexpected toxicities were recorded, and only eight patients suspended from any study drug. Of note, 21 (45.7%) patients reported peripheral neuropathy (PN) (grades 1-2 with no serious adverse events). IRd induction and consolidation with transplant before lenalidomide maintenance shows lower response rates compared to other triplet therapies. It could be an alternative for patients who require an all-oral regimen and/or with pre-existent PN, especially if quadruplet regimens including anti-CD38 antibody are not available.

Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma, Version 2.2024, NCCN Clinical Practice Guidelines in Oncology

Chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL) are essentially different manifestations of the same disease that are similarly managed. A number of molecular and cytogenetic variables with prognostic implications have been identified. Undetectable minimal residual disease at the end of treatment with chemoimmunotherapy or venetoclax-based combination regimens is an independent predictor of improved survival among patients with previously untreated or relapsed/refractory CLL/SLL. The selection of treatment is based on the disease stage, presence or absence of del(17p) or TP53 mutation, immunoglobulin heavy chain variable region mutation status, patient age, performance status, comorbid conditions, and the agent's toxicity profile. This manuscript discusses the recommendations outlined in the NCCN Guidelines for the diagnosis and management of patients with CLL/SLL.

Abstract A077: The utility of surgical minimal residual disease after frontline treatment for prognostic and investigational opportunities in advanced ovarian cancer

Abstract Cure rates for patients with advanced stage ovarian cancer have not changed significantly 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 and tumor dormancy, 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 and pathological 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 (combination of surgery and platinum-taxane chemotherapy) who underwent SLL from 4/2017-6/2023. 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: 70 patients underwent SLL with a median of 8.5 biopsies (range 3-16). The majority of patients had stage III-IV disease (90%), and high-grade serous histology (90%). Approximately half (51.4%) of patients underwent neoadjuvant chemotherapy (NACT) with interval tumor reductive surgery (TRS). MRD was present in 32 patients (45.7%), and the presence of MRD was associated with a worse PFS (HR 3.0, 95% CI 1.5-5.8; 12.5 vs. 24.8 months; p=0.001). MRD was more frequent among NACT recipients compared to those who underwent primary TRS (63% vs 26%, P=0.002), those with HRD negative tumors (58% vs 24%, P=0.025), and those with R1 versus R0 resections (71% vs 39%, P=0.024). Of patients with MRD, 22 patients (71%) received bevacizumab until progression as part of a clinical trial (NCT02884648), 3 (10%) received bevacizumab off trial, 5 (16%) received a PARP inhibitor (all HRD positive), and 1 received other therapy. There were two (2.9%) intraoperative complications (both enterotomies) requiring conversion to laparotomy. Conclusions: SLL is feasible, overall safe, and detected MRD in 46% of ovarian cancer patients who were in radiologic and CA-125 remission after frontline therapy. PFS was significantly shorter for patients with residual disease, despite those patients all receiving additional therapy. Knowledge of MRD status in this patient population enables interventional, observational, and translational opportunities, as well as personalized prognostic counseling. MRD rate may also have utility as an early surrogate for efficacy in trials evaluating novel frontline investigational therapies. Future studies will compare the performance of circulating tumor DNA (ctDNA) versus surgical MRD. Citation Format: Anne Knisely, Roni Nitecki, J. Alejandro Rauh-Hain, R. Tyler Hillman, Jolyn S. Taylor, Lois M. Ramondetta, Michaela O. Grinsfelder, Lauren P. Cobb, David M. Boruta, Gwyn Richardson, Pamela T. Soliman, Aaron Shafer, Shannon N. Westin, Nicole D. Fleming, Travis T. Sims, Anil K. Sood, Pedro T. Ramirez, Karen H. Lu, Amir A. Jazaeri. The utility of surgical minimal residual disease after frontline treatment for prognostic and investigational opportunities in advanced ovarian cancer [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr A077.

Ixazomib, Lenalidomide, and Dexamethasone (IRD) Treatment with Cytogenetic Risk-Based Maintenance in Transplant-Eligible Myeloma: A Phase 2 Multicenter Study by the Nordic Myeloma Study Group.

Scarce data exist on double maintenance in transplant-eligible high-risk (HR) newly diagnosed multiple myeloma (NDMM) patients. This prospective phase 2 study enrolled 120 transplant-eligible NDMM patients. The treatment consisted of four cycles of ixazomib-lenalidomide-dexamethasone (IRD) induction plus autologous stem cell transplantation followed by IRD consolidation and cytogenetic risk-based maintenance therapy with lenalidomide + ixazomib (IR) for HR patients and lenalidomide (R) alone for NHR patients. The main endpoint of the study was undetectable minimal residual disease (MRD) with sensitivity of <10-5 by flow cytometry at any time, and other endpoints were progression-free survival (PFS) and overall survival (OS). We present the preplanned analysis after the last patient has been two years on maintenance. At any time during protocol treatment, 28% (34/120) had MRD < 10-5 at least once. At two years on maintenance, 66% of the patients in the HR group and 76% in the NHR group were progression-free (p = 0.395) and 36% (43/120) were CR or better, of which 42% (18/43) had undetectable flow MRD <10-5. Altogether 95% of the patients with sustained MRD <10-5, 82% of the patients who turned MRD-positive, and 61% of those with positive MRD had no disease progression at two years on maintenance (p < 0.001). To conclude, prolonged maintenance with all-oral ixazomib plus lenalidomide might improve PFS in HR patients.

Modified EASIX scores predict severe CRS/ICANS in patients with acute myeloid leukemia following CLL1 CAR-T cell therapy.

Chimeric antigen receptor T (CAR-T) cell therapy targeting CLL1 has been considered a potent weapon for patients with acute myeloid leukemia (AML). This study aims to evaluate the efficacy and toxicity of CLL1 CAR-T cell therapy in a larger cohort, with particular attention to cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). Among the 32 patients assessed for efficacy, complete remission occurred in 71.88% (23/32) of cases and undetectable minimal residual disease in 14 patients. The CRS developed in all patients, with 8 individuals experiencing ICANS. Severe CRS and ICANS were observed in 11 and 2 patients, respectively. Furthermore, the Endothelial Activation and Stress Index (EASIX) and its derivatives measured before and after CLL1 CAR-T cell infusion were employed for predicting the severe complications. Significant differences were observed in EASIX scores on the day before lymphodepletion (Day BL, P = 0.023), -1 (P < 0.001), +1 (P < 0.001), and +3(P = 0.014); sEASIX scores on Day BL (P = 0.007), -1 (P < 0.001), +1 (P < 0.001), and +3 (P < 0.001); and mEASIX score on Day -1 (P = 0.004) between patients with mild and severe CRS/ICANS. Additionally, there was a significant difference in mEASIX scores between responders and non-responders on Day BL (P = 0.004) and Day -1 (P = 0.044). Our findings indicate that pre- and post-infusion assessments of EASIX/mEASIX/sEASIX scores serve as reliable prognostic indicators for severe CRS/ICANS and treatment response following CLL1 CAR-T cell therapy, which can assist physicians in implementing preemptive treatment strategies for potential severe complications and screening patients who are suitable candidates for CLL1 CAR-T cell therapy. EASIX/mEASIX/sEASIX scores serve as reliable prognostic indicators for severe CRS/ICANS following CLL1 CAR-T cell therapy. The preinfusion mEASIX scores of CLL1 CAR-T cells can effectively predict treatment response.

Five-year follow-up of a phase 2 study of ibrutinib plus fludarabine, cyclophosphamide, and rituximab as initial therapy in CLL

AbstractWe previously reported high rates of undetectable minimal residual disease <10−4 (uMRD4) with ibrutinib plus fludarabine, cyclophosphamide, and rituximab (iFCR) followed by 2-year ibrutinib maintenance (I-M) in treatment-naïve chronic lymphocytic leukemia (CLL). Here, we report updated data from this phase 2 study with a median follow-up of 63 months. Of 85 patients enrolled, including 5 (6%) with deletion 17p or TP53 mutation, 91% completed iFCR and 2-year I-M. Five-year progression-free survival (PFS) and overall survival were 94% (95% confidence interval [CI], 89%-100%) and 99% (95% CI, 96%-100%), respectively. No additional deaths have occurred with this extended follow-up. No difference in PFS was observed by immunoglobulin heavy-chain variable region gene status or duration of I-M. High rates of peripheral blood (PB) uMRD4 were maintained (72% at the end of iFCR, 66% at the end of 2-year I-M, and 44% at 4.5 years from treatment initiation). Thirteen patients developed MRD conversion without clinical progression, mostly (77%) after stopping ibrutinib. None had Bruton tyrosine kinase (BTK) mutations. One patient had PLCG2 mutation. Six of these patients underwent ibrutinib retreatment per protocol. Median time on ibrutinib retreatment was 34 months. The cumulative incidence of atrial fibrillation was 8%. Second malignancy or nonmalignant hematologic disease occurred in 13%, mostly nonmelanoma skin cancer. Overall, iFCR with 2-year I-M achieved durably deep responses in patients with diverse CLL genetic markers. Re-emergent clones lacked BTK mutation and retained sensitivity to ibrutinib upon retreatment. This trial is registered at www.clinicaltrials.gov as #NCT02251548.

Phase 2 study of ibrutinib plus venetoclax in Japanese patients with relapsed/refractory mantle cell lymphoma

BackgroundDespite high response rates to initial therapy, most patients with mantle cell lymphoma (MCL) experience relapsed or refractory (R/R) disease. Here, we report the efficacy, safety, and pharmacokinetics of the Phase 2, single-arm M20-075 study (NCT04477486) of ibrutinib and venetoclax combination therapy in Japanese patients with R/R MCL.MethodsPatients received 560 mg ibrutinib and 400 mg venetoclax (after a 5-week ramp-up from 20 mg) once daily for up to 104 weeks. Primary endpoint was complete response (CR) rate by independent review committee (IRC). Secondary endpoints included overall response rate (ORR), duration of response (DOR), undetectable minimal residual disease (uMRD) rate, progression-free survival (PFS), overall survival (OS), safety including dose-limiting toxicity (DLT) assessment in the first six patients, and pharmacokinetic parameters. Full analysis set (FAS) comprised all treated patients. Per protocol set (PPS) excluded treated patients with non-evaluable disease at baseline by IRC.ResultsThirteen patients were treated (FAS n = 13; PPS, n = 12). Median age was 71 years, patients had a median of two prior treatments. After a median follow-up of 9.6 months, IRC-assessed CR rate and ORR were both 83% (PPS). All six MRD-evaluable patients had uMRD. Median DOR, PFS, and OS were unreached. The most common Grade ≥ 3 treatment-emergent adverse event (TEAE) was neutropenia (23%); 1 patient discontinued due to squamous cell carcinoma of the lung. No DLTs, tumor lysis syndrome, or deaths related to TEAEs were observed.ConclusionIbrutinib plus venetoclax exhibited high response rates and a well-tolerated safety profile in Japanese patients with R/R MCL.

Relationship Between Venetoclax Exposure and Undetectable Minimal Residual Disease Rates in Relapsed/Refractory Patients With Chronic Lymphocytic Leukemia: A Pooled Analysis of Six Clinical Studies.

Relationship Between Venetoclax Exposure and Undetectable Minimal Residual Disease Rates in Relapsed/Refractory Patients With Chronic Lymphocytic Leukemia: A Pooled Analysis of Six Clinical Studies.

Post-CAR-T Minimal Residual Disease (MRD) Monitoring in Mantle Cell Lymphoma Enables Early Relapse Detection

INTRODUCTION: Over 40% of patients with mantle cell lymphoma (MCL) will progress within 1 year after treatment with brexucabtagene autoleucel (Brexu-cel)(Michael Wang et al. ZUMA-2 NEJM 2020). Monitoring minimal residual disease (MRD) of circulating tumor cells (CTC) via next-generation sequencing of the immunoglobulin sequences (IgHTS) with a sensitivity of 1 in million (ClonoSeq, Adaptive Biotechnologies) has previously been shown to identify patients at high risk of MCL relapse (Simone Ferrero et al. Blood 2022). However, there is a limited understanding of MRD monitoring after Brexu-cel. A sub-analysis of 27 patients post-Brexu-cel in ZUMA-2 showed predictive performance of MRD measured at months 1, 3, and 6 in estimating relapse potential. METHODS: Clonotypes were identified from paraffin-embedded tissues and underwent PCR amplification of the IgH, IgH-DJ, and Ig Kappa/lambda regions. CTC MRD assessments were monitored at 1, 3, 6, and 12 months (if applicable) following standard-of-care brexu-cel infusion in all patients with MCL at our center who had at least 3 months of follow-up. PFS and overall survival (OS) were determined by Kaplan-Meier analysis and significance by log-rank test. The comparison between the two groups was conducted using a two-tailed Mann-Whitney test. Significances were calculated using a Fisher exact test between two categorical variables or as otherwise specified. Statistical analysis and plots were generated using Prism 8.4.1 (GraphPad) RESULTS: Between January 2020 and December 2022, all treated patients (n=34) were analyzed. 3 patients were excluded as they were unable to reach day 28 (D28) assessments due to death, progressive disease, or refusal of CAR-T infusion. 5 patients were excluded due to a follow-up of &amp;lt;3 months. The median follow-up time for the 26 included patients was 18.9 months. The median age was 68, 73% were male and 27% were female, 4 median lines of therapy prior, including AutoHSCT (34.6%) or BTKi (92%). The best overall response rate at D28 was 100% with a CR rate of 73% which was similar to ZUMA-2. The median OS was 18.9 months and the median PFS was 15.3 months. We chose to analyze the Day 28 MRD assessment and found 17 of 23 patients (74%) had undetectable MRD and 6 patients had detectable MRD (26%). Due to the relatively small sample size, no significant differences were found between Age, Gender, Pre-treatment LDH, MIPI score, Ki-67, TP53 mutational status, and probability of Day 28 undetectable MRD. Notably, however, 3 of the 6 patients with TP53 mutations had detectable Day 28 MRD. Those patients with detectable MRD compared with those with undetectable MRD had a lower median PFS of 10.74 months vs 17.69 months (p-value= 0.21, Figure 1); although the median OS was similar of 17.69 and 17.84 months, (p-value= 0.75) respectively. 88% of patients (15 out of 17) with undetectable MRD on Day 28 not only maintained this status at 6 months but also showed no radiological disease progression in 93% (14 out of 15) of cases at the time of longest follow-up. A total of 7 patients relapsed during follow-up. MRD predicted 6 impending relapses earlier than PET CT with a median of 294 days (range 15-332 days) prior to progression (Figure 2). CONCLUSION: Evidence from the ZUMA-2 study and our study highlights the significance of early post-CAR-T MRD as an independent prognostic marker for predicting disease recurrence and durable remissions in MCL. Combining MRD measurements with PET-CT at months 1, 3, and 6 after CAR-T therapy can effectively identify high-risk patients for disease progression, offering promising potential to improve outcomes in MCL.

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.

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.

Single-Cell RNA-Seq Analysis Reveals Distinct Tumor and Immunosuppressive T Cell Phenotypes in CLL Patients Treated with Ibrutinib

Introduction: The development of Bruton tyrosine kinase inhibitors (BTKIs) and their introduction into clinical practice represents a major advance in the treatment of chronic lymphocytic leukemia (CLL). Monotherapy with ibrutinib or other BTKIs generally do not induce complete remissions or undetectable minimal residual disease (uMRD) even with extended therapy. The reason why some patients relapse, and some have minimal residual disease is unknown. Therefore, there is a need to understand the differences between ibrutinib sensitive and resistant CLL cells along with the immune microenvironment to identify novel therapeutic targets. Methods: Here, we investigate the cellular heterogeneity of peripheral blood mononuclear cells from patients with CLL treated with ibrutinib using single-cell RNA sequencing. To understand ibrutinib resistance mechanisms, samples were collected from 8 patients at baseline (before treatment) (1), where BTK C481S is present with low variant allele frequency (VAF) (2) and at time of relapse (3). Data from these were compared to ibrutinib sensitive patient samples at baseline (1) (before treatment), 3yr (2) and 5yr (3) on treatment timepoints. Single cells were isolated using the 10X Genomics 5' immune profiling kit. Data were processed with CellRanger v3.1.0. Poor quality cells were filtered out based on a high proportion of mitochondrial reads and low overall feature count. Sample variation was reduced using Batchelor to aid clustering. Clustering was performed using the partitioning and Leiden methods. Cluster top markers were calculated using functions from monocle3. Identity mapping was performed using Seurat and a published PBMC reference dataset. Results: Single-cell RNA sequencing revealed transcriptional heterogeneity within the B cell cluster (Fig 1A). Three subpopulations of B cells were defined based on differential representation in the ibrutinib-sensitive and resistant patients. Ibrutinib sensitive cells showed enrichment of B cell populations with upregulation of MHC I molecules and TNF family members. We also identified that inflammatory response and metabolic-related pathways were decreased, whereas cellular response to stress and DNA repair programs were increased in the ibrutinib resistance samples. Gene module analysis showed that ibrutinib sensitive samples had an increase in T cell activation, RNA splicing, cell adhesion and migration programs during therapy. We hypothesized that the emergence of BTK C481S mutation in ibrutinib-resistant cells would lead to a distinct transcriptional profile. Long-read sequencing was performed using Oxford Nanopore technology. BTK-mutant cells were identified based on the presence of two or more unique RNA molecules detected with the C481S mutation and these were predominantly identified in the low-VAF and relapse samples. However, there was no significant difference between BTK-mutant cells and the remaining B cells. To see if T cell phenotypes reflected the differences observed in B cell transcriptional state, we characterized and quantified T cell populations according to ibrutinib response and investigated the changes in the T cell population. Ibrutinib markedly increased CD4+ and CD8+ T cell numbers in both resistant and sensitive CLL patients. However, there was a significant (p&amp;lt;0.05) enrichment of Tregs in the ibrutinib-resistant samples. We found a connection between the immunosuppressive phenotype in the microenvironment demonstrating tumor's intrinsic immunological reactive program with exhausted T cells. Also, we found significant difference in the expression of checkpoint molecules and suppressive genes in T cells (Fig 1B) and NK cells. Conclusion: Our findings demonstrate that the B cell population in ibrutinib-resistant and ibrutinib sensitive CLL patients exhibit distinct transcriptional states. At the single-cell level, our findings demonstrate a systematic picture of diverse malignancy and microenvironmental changes in CLL. Overall, these findings provide an insight into the complex molecular and cellular interactions of CLL that may have a crucial role in BTKI resistance.

Asparaginase-Associated Toxicities and Hypersensitivity Reactions in Pediatric and Adolescent Down Syndrome Patients with Acute Lymphoblastic Leukemia or Lymphoma

Children with Down syndrome acute lymphoblastic leukemia (DS-ALL) have worse prognosis compared to those with non-DS-ALL, largely due to higher treatment related mortality. Pegaspargase (PEG) is integral in protocols for the treatment of pediatric ALL and lymphoblastic lymphoma (LBL), and full exposure to all doses of PEG can be limited by toxicities, including hypersensitivity reactions (HSR) due to the production of anti-asparaginase antibodies rendering PEG therapy ineffective. To date, minimal data has been reported on the use of PEG in children with DS-ALL/LBL. We conducted a prospective, multicenter study to evaluate the efficacy of premedicating pediatric and adolescent ALL/LBL patients receiving PEG with antihistamines-H1 and -H2 blockers with subsequent therapeutic drug monitoring (TDM) to better identify patients with true HSR versus those with non-antibody mediated infusion reactions. Here, we report on the incidence of HSRs and PEG-associated toxicities in the cohort of children with DS-ALL/LBL. Eligible patients from six centers received PEG, as per a Children's Oncology Group protocol, beginning in induction therapy. An H1 blocker (diphenhydramine) and H2 blocker (ranitidine, famotidine or cimetidine) were administered prior to PEG administration in consolidation and subsequent cycles. TDM was performed at 7 and 14 days post each PEG. PEG was administered at 2500 International units/m 2/dose that was capped for obesity or age &amp;gt; 22 years. Patients were monitored for HSR and other PEG-related toxicities using CTCAE version 5 criteria. Therapeutic asparaginase activity (AA) was defined as ≥ 0.1 IU/mL (≥100 IU/L) at 7 days post infusion and greater than the lower level of quantification at 14 days. We observed for silent inactivation (subtherapeutic levels without symptoms) and accelerated clearance (levels below quantification at 14 days without symptoms). Descriptive statistics summarized patient characteristics and mixed effects modeling procedure assessed mean AA levels at 7 and 14 days with specification of repeat measures and compound symmetry covariance structure. Out of 148 patients, 9 DS (8 B-ALL, 1 B-LBL) were enrolled between 10/2019 - 3/2022. The median age at diagnosis was 5.0 years [IQR: 4.3, 14.9], 4 were National Cancer Institute (NCI) High Risk (HR) at diagnosis, 4 were Hispanic and none were obese. ALL 9 DS patients received a total of 26 doses of PEG at the standard dose without dose capping required. The mean unadjusted AA levels at 7 and 14 days post PEG were 0.76 IU/ml (SE=0.11) and 0.54 IU/ml (SE=0.11), respectively, p&amp;lt;.001. None of the DS patients experienced HSR or silent inactivation. Accelerated clearance was observed in 1 patient. Nineteen episodes of grade &amp;gt;3 PEG-associated toxicity were observed in 5 DS-ALL patients (5/9; 55.6%). PEG-associated toxicity was observed more frequently in older patients whose mean age was 13 years (SD=6.2) versus 4.3 years in those without toxicity (SDE=0.9), p=.028. Four of the DS-ALL who experienced toxicities were NCI HR at diagnosis and &amp;gt; 10 years of age. For the 19 episodes of toxicities: 6 occurred during induction, 9 during consolidation, and 4 during delayed intensification. The most common toxicity observed was hepatoxicity (increased alanine transaminase) which was experienced by 3 DS-ALL patients. There were no grade &amp;gt; 3 hyperbilirubinemia. All 4 DS-ALL patients who experienced PEG toxicity during induction also had toxicity with subsequent cycles. One DS-ALL patient had a dose limiting toxicity (grade 3 pancreatic pseudocyst), requiring discontinuation of subsequent PEG therapy. There were no grade 4 or 5 toxicities observed. All 4 DS patients who did not experience toxicities were NCI Standard Risk patients. All DS patients had undetectable minimal residual disease (MRD) that was &amp;lt; 0.01 at the end of induction therapy. We noted that in this small DS-ALL/LBL cohort, none of the patients experienced HSR, and all achieved therapeutic AA at both time points of 7 and 10 days post PEG. Five (55.6%) of the DS-ALL patients experienced at least one grade &amp;gt; 3 asparaginase toxicity, and they were older than those without toxicity. Most toxicity occurred during the consolidation phase and no grade 4 or 5 toxicities were observed. Given the PEG-associated toxicity observed in DS ALL/LBL, we are conducting pharmacokinetic analysis to propose a lower dose of PEG which may minimize toxicity while maintaining therapeutic efficacy.

Initial Results of a Phase 2 Study of Venetoclax Added to Ibrutinib to Eliminate Ibrutinib Resistance Mutations in CLL

CONCLUSION BTK inhibitors (BTKi) are an important treatment for CLL. As BTKi are given until intolerance or disease progression, resistance is a major challenge. Progressive disease (PD) during BTKi treatment is associated with mutations BTK itself, or the immediate downstream protein, PLCG2. These can be detected 9-12 months prior to PD allowing for intervention. Venetoclax (VEN) is effective after IBR treatment, decreases BTK C481S mutation VAF, and can be combined with IBR. Based on these data, this phase 2 study adding VEN to IBR in patients (pts) with resistance mutations (RMUT) was conducted to test the hypothesis that adding VEN could eliminate molecular resistance. CLL pts taking IBR and with a detectable RMUT with or without PD were eligible. Included RMUT were in BTK at C481 and T474 or in PLCG2 at L845, D334, D1140, R665, and S707. Eligible pts continued IBR and added VEN. VEN was given in cycles (C) of 28 days with standard 5-week dose ramp-up to 400mg daily. Response was assessed after C12 and C24 by iwCLL 2008 criteria. Pts achieving a complete remission (CR) or CR with incomplete marrow recovery (CRi) and undetectable minimal residual disease (uMRD) to a level of 10-4 in both blood and marrow discontinued treatment. Those without a uMRD CR/CRi continued through C24 then discontinued if in uMRD CR/CRi. If this response was still not achieved after C24, they stopped IBR and continued VEN alone. Sequencing for RMUT was performed using an assay with a sensitivity of ≥0.5% VAF on sorted CD19+ B-cells. The primary endpoint is the rate of undetectable RMUT after C12 of IBR and VEN. Secondary endpoints are rate of uMRD CR/CRi after C12, progression-free (PFS), and overall survival (OS). C12 assessments missed due to the COVID-19 pandemic were considered non-assessable (NA). A second analysis included delayed C12 assessments. Adverse events (AEs) were graded according to the CTCAE v5 except hematologic AEs which used iwCLL criteria. Kaplan Meier methods were used to assess PFS and OS. All statistical analyses were performed using SAS version 9.4 (SAS Institute, Inc., Cary, NC). Data cut was 7/13/2023. A total of 28 pts were enrolled between 3/2019 and 2/2022 with baseline characteristics in the Table. The median follow up was 31.7 months (range 2.8-47.0) and 8 (29%) pts remain on treatment, 9 (32%) in follow up off treatment, 10 (40%) off study, and 1 (4%) died. BTK C481S testing was available after baseline at time of analysis. After C12, 13/27 (48%) pts who had a BTK C481S mutation at baseline had undetectable BTK C481S (uBTK C481S). This increased to 16/27 (59%) with C12 delayed assessments. 19/27 (70%) pts had uBTK C481S at anytime on study with a median time to uBTK C481S of 6 months (range 2.0-19.8). Of these 6/19 (32%) regained detectable BTK C481S with a median duration of uBTK C481S of 13.8 months (range 5.3-28.8) and 3/6 had PD. After C12 the overall response rate (ORR) was 71% (4 CR, 4 CRi, 12 partial remissions [PR], 4 stable disease [SD], 1 PD, 3 NA). Including delayed assessments (at C16, C19, and C19), the ORR was 79% (NA-&amp;gt;PR n=2, PR-&amp;gt;CR n=1). uMRD CR/CRi was attained in 5/28 (18%) and 6/28 (21%) pts after C12 and including delayed assessments, respectively. 12/28 (43%) pts discontinued treatment due to response: 9/28 (32%) in uMRD CR/CRi (C12 n=4, C19 n=1, C25 n=4), 3/28 (11%) electively in CR with detectable MRD (n=1, C12) or PR with uMRD (n=2, C25). Eight (36%) pts had PD with 1 Richter Transformation. The median PFS and OS were 40.7 months (95% CI: 35.9-not reached) and not reached, respectively (Figure). Hematologic AEs were frequent with lymphopenia (75%, 46% grade [gr] 3+), thrombocytopenia 68%, 7% gr 3+), neutropenia (61%, 14% gr 3+), and anemia (43%, 0% gr 3+). AEs experienced by &amp;gt;40% of pts were hypocalcemia (75%), diarrhea (75%), weight loss (57%), hypertension (57%), increased lactate dehydrogenase (54%), nausea (54%), dizziness (50%), vomiting (50%), flu like symptoms (43%), and neoplasms (43%). Gr 3 non-hematologic AEs occurring in &amp;gt;10% of pts were hypertension (21%) and diarrhea (14%). Seven (25%) patients had COVID-19 (all gr 2). There were no episodes of tumor lysis syndrome. In this phase 2 study, the addition of VEN to IBR decreased the BTK C481S mutation below the detection limit in 59% of pts after 12 cycles of treatment. This combination allowed 32% of pts to discontinue treatment in deep remission. The median PFS (40.7 months) supports further investigation of this approach.

The Impact of Fitness and Dose Intensity on Safety and Efficacy Outcomes after Venetoclax-Obinutuzumab in Previously Untreated Chronic Lymphocytic Leukemia

Introduction Following the results of two phase-III studies, the CLL14 study, recruiting elderly and unfit patients (pts) with chronic lymphocytic leukemia (CLL), and the CLL13 study, recruiting younger and fit pts, venetoclax-obinutuzumab (Ven-Obi) is a standard of care for pts with treatment-naive CLL. However, it is unclear whether age and/or fitness have an impact on the tolerability and efficacy of Ven-Obi. Furthermore, the impact of dose reductions on response and survival has not been explored yet. Here, we present a pooled analysis detailing the toxicity and efficacy of Ven-Obi in pts treated within the CLL13 and CLL14 studies. Methods Patients randomized to the Ven-Obi arm in CLL14 (2015-2016) and CLL13 (2016-2019) with at least one dose of study drug were considered and categorized as fit or unfit pts (cumulative illness rating scale [CIRS] &amp;gt; 6 and/or creatinine clearance &amp;lt; 70 ml/min). Patients with TP53 aberrations were excluded to ensure balanced features across the CLL13 and CLL14 populations. Correlations regarding minimal residual disease (MRD) in peripheral blood and response (both assessed at the end of treatment [EOT]) were assessed by chi² test. Progression-free survival (PFS) and overall survival (OS) were analyzed by Kaplan-Meier methodology and Cox proportional hazard regression modeling. Dose intensity was calculated as the relative fraction within the administered treatment cycles (excluding pts with treatment discontinuation due to PD/death). Adverse events were analyzed up to 28 days after EOT. Results In total, 410 pts were considered for this analysis, 228 from CLL13 and 182 from CLL14. The median observation time was 49 months (interquartile range [IQR] 37.0-65.8 months); for CLL13, median observation time was 38.9 months (IQR 33.8-46.3), and 66.7 months in CLL14 (IQR 64.4-70.8). Median age at enrollment was 67 years (IQR 58-73); 55.7% were grouped as unfit (median age 72), 44.3% as fit (median age 58) ( A). Overall response rate (ORR) was 89.5% in unfit and 96.1% in fit pts (p=0.011), CR rates were 51.8% and 54.1% (p=0.63), respectively. The undetectable MRD (&amp;lt;10 -4) rates were 80.3% in unfit and 85.1% in fit pts (p=0.2). The 3-year-PFS rates were 86.4% in unfit vs 87.5% in fit pts (HR 1.12, 95%-CI 0.70-1.81, p=0.63, B). The 3-year-OS was 91.8% in unfit vs 96.9% in fit pts (HR 2.02, 95% CI 0.90-4.55, p=0.088). Adverse events (any grade) considered of interest included neutropenia, which occurred in 62.7% of unfit and 56.9% of fit pts (febrile neutropenia 4.4% in each group), respectively. Infusion-related-reactions (IRR) occurred in 44.3% of unfit and 56.9% of fit pts. Fatigue was reported in 15.8% of unfit and 35.9% of fit pts; headaches in 9.2% of unfit and 18.2% of fit pts. Infections occurred in 57.5% of unfit and 69.6% of fit pts; in particular, nasopharyngitis was reported for 10.5% of unfit and 24.3% of fit pts. Covid-19 occurred in 3 unfit (3 fatal) and 5 fit (2 fatal) pts. Other common adverse events were balanced between fit and unfit pts. Comparable patterns were also observed when comparing young vs older pts according to exploratory age cut-offs between 65 to 80 years. Early venetoclax discontinuations for reasons other than PD or death (e.g., adverse events, withdrawal) were more common in unfit than in fit pts (15.8% vs 5.0%). Median time to early discontinuation was 6.3 months (3.1-8.7). Patients with early venetoclax discontinuation had a 3-year-PFS from EOT of 71.2%, compared with 83.0% in pts who completed venetoclax as planned (HR 2.25, 95%-CI 1.32-3.83, p=0.003). The 3-year-OS from the EOT was 84.3% and 94.0% (HR 2.48, 95%-CI 1.10-5.59, p=0.029), respectively. Dose reductions &amp;lt;80% (excluding PD/death) occurred in 15.7% of all pts (14.7% unfit, 16.5% fit). ORR in pts with venetoclax dose intensity &amp;lt;80% was 82.5% and 95.9% in pts with dose intensity ≥80% (p&amp;lt;0.001). CR rates were 42.9% and 55.5% (p=0.066), uMRD rates were 76.2% and 85.3% (p=0.073). The 3-year-PFS from the EOT for pts with and without venetoclax dose intensity &amp;lt;80% was 81.0 % and 82.2%, respectively (HR 1.47, 95%-CI 0.84-2.57, p=0.175). Conclusion This analysis confirms the feasibility and efficacy of Ven-Obi for both fit and unfit pts with CLL. The incidence of toxicities was comparable between both patient groups, although IRR and fatigue were more common in fit pts. Reduced venetoclax dose intensity had no impact on PFS, suggesting that dose modifications may have limited impact on long-term clinical outcomes.

Long-Term Outcomes in Chronic Lymphocytic Leukemia Treated with Ibrutinib: 10-Year Follow-up of a Phase 2 Study

Background: Targeted agents have replaced conventional chemotherapy in treatment of chronic lymphocytic leukemia (CLL) with substantially improved outcomes in CLL with TP53 alterations (del17p or TP53 mutations). Whereas fludarabine, cyclophosphamide, and rituximab chemoimmunotherapy (CIT) had a median progression-free survival (mPFS) of 11.2 months and median overall survival (mOS) of 33.1 months as frontline therapy in del17p CLL (Fisher et al. Blood 2016), we previously reported a 6-year PFS of 61% and OS of 79% in CLL with TP53 alterations receiving frontline continuous ibrutinib (Ahn et al. NEJM 2020). In a similar patient subset, the CLL14 study demonstrated a mPFS of 51.9 months and a 5-year OS of 60.0% using fixed-duration venetoclax and obinutuzumab (Al-Sawaf et al. EHA 2023; Al-Sawaf et al. Nat. Comm 2023). Although more effective than CIT, long-term outcomes in the era of targeted therapy are not yet fully defined. With a median follow-up of nearly 10 years, we analyzed efficacy, safety, and depth of response in CLL patients treated with long-term ibrutinib therapy in a phase 2 study (NCT01500733). Methods: Eligible patients had high-risk CLL, defined by TP53 alterations or age ≥65 years-old (N = 84 evaluable), and received ibrutinib 420 mg orally once daily until disease progression or intolerable side effects. Response assessments were performed annually with CT scans up to five years and subsequently with physical exam. Minimal residual disease (MRD) was performed annually with peripheral blood flow cytometry. Undetectable MRD (uMRD) was defined as &amp;lt;1 CLL cell per 10,000 leukocytes. For patients discontinuing the study, long-term outcomes were obtained when possible through a separate natural history study (NCT00923507). Results: As of December 31, 2022, a median follow-up of 113 months and 117 months (reverse Kaplan-Meier) was available for calculation of PFS and OS, respectively. The mPFS for all patients was 85.9 months (Table 1). mPFS was significantly shorter in those with TP53 alterations (67.3 months, N = 53) vs. those without (not reached, N = 31) and in relapsed disease (49 months, N = 32) vs. frontline treatment (108 months, N = 52). The OS at 117 months was 58.5% for all patients, 73.8% for treatment-naïve patients, and 54.1% in patients with TP53 alterations. Among patients with TP53 alterations receiving frontline ibrutinib (N = 34), the mPFS was 81 months with an OS of 69.7% at 117 months. Most patients (82.1%, 69/84) had discontinued ibrutinib at the time of analysis with 15 patients (17.9%) remaining on therapy. 37 (44.0%) patients discontinued ibrutinib for progressive disease including 6 cases with histologic transformation. 27 (32.1%) patients discontinued therapy related to treatment-emergent adverse events (AEs) including 8 cardiac AEs (four cases were grade ≥2 atrial fibrillation), 7 second cancers, 4 infections, 3 cases of dementia (ages 78, 80, and 85), 2 pleural effusions, and 3 other AEs. Five patients (5.9%) withdrew from the study with 4 switching to commercial supply of ibrutinib and one changing to CAR-T therapy. uMRD was observed in 15.4% (13/84) of all patients. The median time to uMRD was 5 years (range: 2 - 10 years). There was no enrichment in these patients for Rai stage ≥3-4, unmutated IGHV, TP53 alteration, prior treatment, or age. Most patients achieving uMRD also had a complete response (CR) to therapy (10/13) and remained progression-free at last follow-up (12/13). The one patient with progressive disease achieved uMRD and CR at 24 months, had detectable MRD at 36 months, and had nodal progression at 60 months. Among the progression-free patients, 8 had subsequent MRD assessments demonstrating sustained uMRD for 1-6 years including one patient who had been off any CLL-directed therapy for 4 years. Conclusions: These results further define the long-term prognosis of patients treated with BTK inhibitors for CLL, most notably with substantial improvements in the OS of patients with TP53 alterations over CIT. Additionally, these results may inform discussions of continuous BTK inhibitor therapy versus fixed-duration venetoclax combinations in frontline therapy of high-risk CLL. In a subset of ibrutinib-treated patients, depth of response increased over multiple years to the point of uMRD suggesting the possibility that such patients might safely discontinue therapy, following paradigms established in patients with chronic myelogenous leukemia.

Preliminary Safety, Pharmacological and Efficacy Data from Patients with Relapsed or Refractory B-Cell Malignancies Treated with the ICP-248, a Next Generation BCL2 Inhibitor

Background: BCL2, a key protein regulator of the apoptotic pathway, is constitutively expressed in various malignancies, which is a hallmark of cancer cell. BCL2 inhibitors have been shown to be safe and effective and are approved for the treatment of patients with chronic lymphocytic leukemia/small cell lymphoma (CLL/SLL) or acute myeloid leukemia (AML). Venetoclax, the first and only approved BCL2 inhibitor, is associated with gastrointestinal toxicities and tumor lysis syndrome (TLS). Therefore, ICP-248 was developed as a potent and highly selective inhibitor of BCL2 and has shown antitumor activity superior to venetoclax in preclinical studies. Preclinical studies of ICP-248 have demonstrated favorable pharmacokinetics profile, broad safety window and excellent safety profile, as well as synergistic effect in anti-tumor activity in combination with Orelabrutinib, a novel and highly selective BTK inhibitor. Methods: ICP-CL-1201 is a phase I study to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics, and preliminary efficacy of ICP-248 in patients with relapsed or refractory B-cell malignancies ( ClinicalTrials.gov ID: NCT05728658). The study will be conducted in 2 parts. Part 1 will evaluate ICP-248 as monotherapy at the target dose of 100mg, 200mg, 300mg, 400mg, 500mg and 600mg (once daily and 28 days per cycle) and will explore different ramp-up dosing strategies. Part 2 will evaluate ICP-248 in selected and proposed indications. The dose escalation in Part 1 will follow the 3+3 design with dose-limiting toxicity (DLT) observation window with 49 days. Eligible patients include those with CLL/SLL and B-cell non-Hodgkin lymphomas (NHLs) who failed on available therapy. Key exclusion criteria include CNS involvement, prior exposure to BCL2 inhibitors and clinically significant cardiovascular disease. Adverse events (AEs) are reported per common terminology criteria for AEs (CTCAE) v5.0. Efficacy was evaluated according to the Lugano 2014 or International Workshop on Chronic Lymphocytic Leukemia (iwCLL) 2018 criteria. Minimal residual disease was evaluated with flow or next generation sequencing. Results: As of 30 th July, 2023 (data cutoff date) 3 patents (mantle cell lymphoma [MCL], SLL and CLL) had been enrolled at the dose level of 100 mg QD; age ranging from 53 to 68; follow-up ranging from 1.9 to 4.7 months); median of prior regimen numbers was 3 (range, 1-3; 2 out 3 patients failed on zanubrutinib or pirtobrutinib). ICP-248 demonstrated a favorable PK profile, approximate dose proportionality was observed across the ramp-up stage. No DLTs and SAEs were observed. All the AEs were grade 1 to 2 (mainly neutropenia) without dose interruption and modifications. No TLS including laboratory TLS was observed. Two patients with MCL and SLL were assessed as complete response (CR) at the end of cycle 2, and the CLL patient was assessed as stable disease without sign and symptom of disease and recovering hematology. Undetectable MRD was confirmed in the patient with SLL and MCL. Conclusions: Preliminary results suggest that ICP-248 is safe and well tolerated in relapsed or refractory B-cell malignancies. The favorable clinical pharmacological and safety profiles support current dose ramp up strategy. Preliminary efficacy data demonstrated good response with deep remission. Further assessment of safety and efficacy with additional dose levels and dosing strategies will be pursued in expanded patient population and in the combination with orelabrutinib.

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 &amp;gt; 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.

Comparison of Venetoclax Based Treatments for Patients with Relapsed/Refractory Chronic Lymphocytic Leukemia

Background: Venetoclax (Ven) is a BCL-2 inhibitor that produces deep responses with high rates of undetectable minimal residual disease (uMRD) for patients (pts) with chronic lymphocytic leukemia (CLL) (Al-Sawaf et al. 2020). Currently, ven is FDA approved as either monotherapy (mono) or in combination (combo) with rituximab (R) In patients with relapsed/refractory (R/R) CLL (Seymour et al. 2018). However, the optimal ven based treatment (tx) for pts with R/R CLL either as mono, or in combo with anti-CD20 monoclonal antibody (mab), or bruton tyrosine kinase inhibitor (BTKi) is uncertain. We performed a single institution retrospective analysis of pts with R/R CLL treated with ven based regimens evaluating efficacy of different ven based txs. Methods: 98 pts with R/R CLL treated between the years of 2012 and 2023 were evaluated. Ven based treatment consisted of ven mono or in combo with R, obinutuzumab (G), or ibrutinib (BTKi) with standard ven dose ramp up to a maximum dose of 400mg daily. R and G were administered per FDA standard dosing. Ibrutinib was administered as 420mg daily, as either fixed or continuous duration tx. Response assessment was performed using iwCLL criteria. Minimal residual disease (MRD) was assessed by multi-parametric peripheral blood flow cytometry with a sensitivity of 10 -4. Time-to-event analyses were performed with the Kaplan-Meier method, with log-rank test used to assess statistically significant differences between variables. Hazard ratios (HR) were calculated by use of Cox proportional modelling. Results: The pts had a median age of 68 years (range; 46-89). Rai stage at time of tx initiation with ven: I 14.2%; II 36.3%; III 8.8%; Stage IV 40.7%. The median number of previous txs was 4 (range; 1-14). Pts harbored the following cytogenetic abnormalities: del(13q) 50.5%; del(11q) 18.5%; trisomy 12 15.5%; normal 15.5%; del(17p)/TP53 mutation 24.7%; and complex in 33%. Seventy percent of pts harbored an unmutated immunoglobulin heavy chain. 25.5% of pts had genomic complexity, with ≥ 5 gene mutations. 43.9% of pts were treated with ven mono; 19.4% were treated with venR; 25.5% of pts were treated with venG; and 11.2% of pts were treated with ven + BTKi. The median number of months of ven based tx was 16.3 (range; 0.9-118.6). 14.3% of pts currently remain on ven. 60.8% of pts had progression after ven based tx; with 62.2% requiring additional tx. 15.3% of pts developed Richter's Transformation. The best overall response for the cohort was: CR 67%; PR 24.5%; SD 1.1%; and PD 7.4%. The best MRD response for the whole cohort was uMRD 76.8%; low MRD 19.5; and high MRD 3.6%. uMRD as best MRD response occurred in 66.7% of ven mono; 82.4% of venR; 86.4% of venG; and 70% of ven + BTKi treated pts. With a median follow-up of 52 months (mo), the median progression-free survival (PFS) for the whole cohort was 67.8 mo. Ven combo had superior PFS to ven mono; median PFS 76.6 vs 58.9 mo (p = 0.04; HR 0.5037; 95% CI 0.2583 - 0.9635). Among the combination treatment approaches, there was a trend for improved PFS for venG compared to ven mono; median PFS not reached (NR) vs 58.9 mo (p = 0.08; HR 0.4385; 95% CI 0.1608 - 1.0240). Similarly, there was also a trend to improved PFS for ven + BTKi compared to ven mono; median PFS NR vs 58.9 mo (p = 0.07; HR 0.2895; 95% CI 0.0462 - 0.9950). Both the presence of del17p/TP53 mutation; and the presence of MRD (+MRD) 12 months after stopping ven based tx were associated with inferior PFS. The median PFS for pts without del17p/TP53 mutation vs with del17p/TP53 mutation was 118 vs 39.7 mo (p &amp;lt; 0.0001; HR 0.2242; 95% CI 0.0533 - 0.8366). Median PFS for pts with uMRD vs +MRD 12 months after ven was NR vs 42.8 mo (p = 0.0001; HR 0.0689; 95% CI 0.0037 - 0.3810). Conclusions : In a high-risk population of pts with R/R CLL, we found that ven based tx leads to durable remissions, with high rates of uMRD. Combo approaches with the addition of either an anti-CD20mab or BTKi led to improved PFS. While venR is the current FDA approved combo regimen for pts with R/R CLL, we found that there was a trend for improved PFS with either venG or ven + BTKi compared to ven mono. Both the presence of a del17p/TP53 mutation and the presence of MRD 12 months after stopping ven based tx significantly adversely affected PFS. However, pts who maintained uMRD 12 months after completing ven, had exceptionally durable long-term remission. This has possible implications for employing MRD adapted txs for pts with CLL.

Bellwave-010: Phase 3, Open-Label, Randomized Study of Nemtabrutinib Plus Venetoclax Versus Venetoclax Plus Rituximab in Patients with Relapsed/Refractory Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma Following at Least One Prior Therapy

Background: Venetoclax + rituximab (VR) is a standard therapy among patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) who have relapsed after at least 1 line of prior therapy. However, there is an unmet need for more effective treatments. Bruton's tyrosine kinase (BTK) is a critical signaling molecule in the pathogenesis of CLL, and inhibitors of BTK have resulted in significant improvements in survival for patients with CLL. Nemtabrutinib is a noncovalent, reversible, competitive inhibitor of BTK that does not require the C481 residue of BTK for binding and inhibition of kinase activity. As a result, nemtabrutinib can target both wild-type and C481-mutant forms of BTK. Results from the ongoing BELLWAVE-001 study have demonstrated manageable safety and durable antitumor activity of nemtabrutinib in patients with CLL/SLL with and without C481 mutations. The randomized, active-controlled, open-label, phase 3 BELLWAVE-010 study (NCT05947851) is designed to investigate the efficacy and safety of nemtabrutinib + venetoclax versus VR as second-line (2L) or later treatment for patients with relapsed/refractory (R/R) CLL/SLL. Study Design and Methods: Patients aged ≥18 years with active CLL/SLL that is relapsed/refractory to at least 1 prior therapy per the iwCLL 2018 criteria, an ECOG performance status of 0-2, and adequate organ function are eligible. Patients with Richter transformation, active central nervous system involvement, or severe bleeding disorder are excluded. Approximately 720 patients will be enrolled in 2 parts: an open-label, nonrandomized dose escalation and confirmation phase (part 1) to evaluate safety and determine the optimal dose of nemtabrutinib in combination with venetoclax and an open-label, parallel-group, randomized phase (part 2) comparing the efficacy and safety of nemtabrutinib + venetoclax with VR. In part 1, 30 patients will be enrolled to establish the dose of nemtabrutinib using a modified toxicity probability interval design. Patients will receive nemtabrutinib at 2 dose levels (45 mg PO QD starting dose, escalating to 65 mg PO QD) for 28 days followed by the combination of nemtabrutinib + venetoclax (20-400 mg PO QD ramp up over 4 weeks). In part 2, approximately 690 patients will be randomly assigned 1:1 to receive either nemtabrutinib at the recommended dose for 28 days followed by the combination of nemtabrutinib + venetoclax (20-400 mg PO QD ramp up over 4 weeks) or venetoclax (20-400 mg PO QD ramp up over 4 weeks) + rituximab (or rituximab biosimilar; 375 mg/m 2 at week 6 followed by 500 mg/m 2 Q4W starting at week 10 until week 26 [total 6 doses]). Patients will receive study treatment for ~2 years or until unacceptable toxicity, disease progression, or other discontinuation criteria are met. Randomization will be stratified by BTK-C481 mutation status (detected vs not detected; determined by droplet digital PCR with a limit of detection of approximately 0.01%-0.1%), geographic region (US/Canada vs Europe vs rest of world) and risk (high risk [del(17p) and/or TP53-mutated and/or IGHV-unmutated] vs low risk [absence of high-risk factors]). Response will be assessed (including imaging, physical examination, constitutional symptoms, hematological evaluations, and bone marrow biopsy as required) every 12 weeks up to week 97 and every 24 weeks thereafter or more frequently if clinically indicated. Adverse events will be monitored up to 30 days after treatment cessation (90 days for serious adverse events) and will be graded per NCI CTCAE, version 5.0. Hematologic toxicities will be evaluated according to iwCLL 2018 criteria. Patient-reported outcomes will be assessed using the EORTC QLQ-C30, EORTC QLQ-CLL17, and EQ-5D-5L questionnaires. The primary end points for part 1 are safety and tolerability, including dose-limiting toxicities, and to establish the recommended dose of nemtabrutinib in combination with venetoclax. The primary end point for part 2 is PFS as assessed per iwCLL 2018 criteria by blinded independent central review (BICR). Secondary end points for part 2 include undetectable minimal residual disease in bone marrow at month 14 as assessed by central laboratory, ORR, and DOR per iwCLL 2018 criteria by BICR, OS, and safety. Exploratory end points include ORR including partial response with lymphocytosis, pharmacokinetics, and health-related quality of life.