Citations

Abstract Background: BCMA- and GPRC5D-targeting immunotherapies including CART cell therapy and Bispecific antibodies are currently approved for the treatment of multiple myeloma. However, clinical outcomes after dual antigenic exposure remain undefined. Herein we report the first report of BCMA-GPRC5D dual targeted multiple myeloma (DEMM). Methods: We conducted a retrospective multi-center study of RRMM patients treated with both BCMA- and GPRC5D-targeted treatments (TT) (CAR T, bispecific antibodies, ADCs) between November 1, 2022, and July 1, 2025. Outcomes included PFS1 (post-dual exposure), and overall survival (OS). Kaplan-Meier estimates and event-free probabilities were calculated. Results: One hundred and fifty patients who underwent TCE treatments were included and 49 patients met the criteria for inclusion. Median age was 65 years, 22.4% had creatinine clearance <=30 and ECOG 2 or greater was present in 22.2%; 57% had high-risk cytogenetics (IMWG 2016), and 60.5% were penta-refractory. Patients received a median of 6 prior lines of therapy (LOT) before 1st TCE and 9 prior LOT before DEMM. 65.3% received 1 TCE, 30.6% received 2 TCE and 4.1% received 3 TCE before DEMM. Similarly, 67.3% received 1 BCMA, 24.5% received 2 BCMA TT and 4.1% received 3 BCMA TT before DEMM. Prior TT included- BCMA CART (57.1%), BCMA Bispecific (57.1%), BCMA ADC (18.4%), other TCE (10.2%). The last dual exposure was GPRC5D Bispecific in 91.8%, BCMA Bispecific in 6.1% and BCMA CART in 2%. The median followup post relapse was 3.4 months (range 0.0-16 mos). The median PFS during the last dual exposure TT was 3.98 months (95% CI: 2.96–6.70). 32.7% did not receive any subsequent LOT and died due to progressive disease. 67.3% of patients had progressive MM and received next LOT. Median PFS1 was 1.77 months (95% CI: 1.28–6.21) with 3-, 6-, and 12-month event-free probabilities of 44%%, 19% and 0% respectively. Median OS was 5.7 months (95% CI: 2.53-12.16) for DEMM from the time of refractoriness to dual antigenic targets. Conclusions: Patients dual-exposed to BCMA- and GPRC5D-directed therapies have a poor prognosis, 32.7% had not received further treatment and in those who received treatment the PFS1 was less than 2 months and an OS of 5.7 months from progression. This reflects an area of high unmet need for the patients that are dual-exposed to BCMA- and GPRC5D-directed therapies. Further data on the cohort will be updated at the meeting. Acknowledgements include, the International Myeloma Foundation, IMWG.

Abstract Background and Significance: Waldenström's Macroglobulinemia (WM) is an indolent B cell disorder characterized by proliferation of clonal lymphoplasmacytic lymphocytes in the bone marrow, lymph nodes, as well as liver and spleen, and secreting a monoclonal IgM Protein. WM is a rare disorder with about 1,700 cases diagnosed in the U.S. each year. There have been significant advances in the management of patients with WM in the last decade, with Bruton's tyrosine kinase (BTK) inhibitors (ibrutinib and zanubrutinib) emerging as a major treatment advancement in this disease. Currently, both BTK inhibitors are approved for the treatment of WM patients with newly diagnosed as well as relapsed/refractory (R/R) disease. BTK inhibitors are effective for the therapy of WM, especially among patients with MYD88 mutation, although the response rates are lower in patients with CXCR4 mutations. In addition, these drugs can cause cardiac side effects such as atrial and ventricular arrhythmias as well as an increased risk of bleeding/bruising. Thus, these drugs can be difficult to use in patients who are older and have cardiac comorbidities. BCL-2 overexpression is well described in a number of B cell malignancies, including WM, leading to inhibition of apoptosis of malignant cells. BCL-2 inhibition with venetoclax has been tested in patients with R/R WM and showed excellent activity with an overall response rate (ORR) of 85% and very good partial response (VGPR) rate of 19%. The therapy was overall well tolerated with no evidence of cardiac toxicity. Given the excellent activity and tolerability of Venetoclax in WM, we are conducting a national cooperative group randomized phase 2 trial comparing ibrutinib+rituximab (IR) vs. venetoclax+rituximab (VR) in patients with newly diagnosed WM. Our hypothesis is that with this trial, we have the potential to develop a more effective therapy targeting BCL-2 for patients with untreated WM, that does not have cardiac or hemostatic toxicity. In addition, we are testing use of a fixed duration therapy with these regimens. Study design and methods: The ongoing clinical trial () is being conducted through the Southwest Oncology Group (SWOG) and is enrolling at multiple SWOG, ECOG, and ALLIANCE centers throughout the US. Major inclusion criteria include 1) newly diagnosed WM confirmed by biopsy and measurable disease (≥0.5 g/dl IgM type paraprotein), 2) meeting WM-related clinical criteria to initiate therapy (cytopenias, B symptoms, bulky lymphadenopathy, neuropathy, hyperviscosity) 3) adequate blood counts (ANC >1000, HGB ≥7.5, PLT ≥50,000), 4) eGFR ≥30 ml/min, 5) adequate liver function tests (total bilirubin ≤1.5 x ULN and AST, ALT and alkaline phosphatase ≤3 x ULN), 6) Zubrod performance status ≤2, 7)prior treatment with single-agent R allowed as long as >6 months prior to registration. Once enrolled the patients will be randomized 1:1 to IR vs. VR. I will be started at 420 mg daily at start of therapy while V will be given at 400mg daily during cycle 1 week 1 and then increased to 800 mg daily from cycle 1 day 8 onwards. R will be given weekly x 4 in cycles 2 and 5. Dose adjustments for both I and V can be done depending on toxicity. Therapy will be given for 2 years and then the patients will be observed off treatment. Patients with disease progression during these 2 years of therapy can cross-over to the other arm. The primary endpoint of the study is rate of VGPR or better. With 41 eligible participants per arm (total N=82), this design has 80% power to reject the null hypothesis of a 25% VGPR rate, given the alternative of a 50% VGPR rate, with a one-sided alpha of 10%. To account for an anticipated 10% ineligibility rate, approximately 46 participants will be accrued per arm (92 total). Current enrollment stands at 15 patients. The secondary end points include ORR, complete response rate, major response rate, progression free and overall survival rates.

Abstract Introduction: While the incidence of multiple myeloma (MM) is 2-3 fold higher in Black compared to white individuals, the impact of racial differences on treatment outcomes remains unclear due to the confounding effect of socioeconomic barriers and disparities in access to effective therapies and clinical trials. In this study, we explored the relationship between race, social deprivation, and outcomes in newly diagnosed MM (NDMM) patients (pts) receiving modern therapies with triplet or quadruplet regimens. Methods: Pts with NDMM diagnosis, who received first line treatment between 2015-2025, and had data available on response and survival outcomes were identified through the ASH Research Collaborative MM Data Hub (a real-world database with pts across 11 U.S. institutions). Data on patient demographics (age, race, ethnicity, sex), disease risk status (ISS/R-ISS stage, FISH cytogenetics), treatment regimens (triplet vs quadruplet, anti CD38 monoclonal antibody-based vs not), and disparity measures were abstracted from electronic medical records. Race and ethnicity were self-reported by pts. Social Deprivation Index (SDI) score was calculated based on ZIP code, where higher scores reflect greater deprivation. Progression free survival (PFS) was defined as time from start of treatment until progression or death. Overall survival (OS) was defined as time from start of treatment until death from any cause. Kaplan-Meier methods were used to compare PFS and OS between groups, and cox regression models with log-rank tests were used to evaluate the influence of various factors on outcomes. Results: A total of 1,743 patients were identified; 1,116 (63.8%) identified as non-Hispanic White (NHW) and 402 (23.3%) as non-Hispanic Black (NHB) [note: 85 pts (4.9%) were Hispanic but not included due to limited numbers]. The median age (years) at the start of treatment (61.8 vs. 65.6) was lower for NHB compared to NHW pts (p<0.001). The proportion of females was greater in NHBthan NHW pts(53.5% vs. 41.1%, p=0.0016). Median SDI scores were significantly higher for NHBcompared to NHW pts (68.4 vs. 39.4; respectively; p<0.001), reflecting significantly higher rates of social deprivation. While NHB ptshad higher rates of advanced stage disease (ISS III 26.9% vs. 20.9%, p=0.009), lower rates of autologous stem cell transplant (ASCT) (56.7% vs. 63.6%, p=0.014), and longer median time from treatment initiation to ASCT (6.5 vs. 5.9 months, p=0.043), the rates of standard risk cytogenetics on FISH (72.3% vs. 77.6%), and utilization of CD38 monoclonal antibody-based regimen (29.9% vs. 27.7%) were similar between the two groups. Best response after treatment initiation was similar between the NHB and NHW pts (p=0.12) with complete response 45.7% vs. 52.6% and very good partial response 37.3% vs 34.7%; respectively. However, time to best response (months) was longer in NHB pts (7.2 vs. 6.5, p=0.005). Median follow-up for OS was 4.2 years (95% CI 3.9-4.4; 182 OS events) and for PFS was 1.3 years (95% CI: 1.1-1.6; 302 PFS events) across the two groups. Unadjusted PFS was similar for NHB vs NHW pts (HR=1.05, 95% CI: 0.81- 1.36; median: 5.0 vs 4.9 years; 3-year PFS: 66% vs. 71%). Similarly, unadjusted OS was not significantly different in NHB vs NHW pts (HR=1.12, 95% CI: 0.79-1.59; 5-year OS: 86.4% vs 85.6%). Higher SDI scores were significantly associated with worse OS (HR=1.07, 95% CI: 1.02-1.12; p=0.0065) but not PFS (HR=0.99, 95% CI: 0.95-1.02; p=0.46). Though not statistically significant, univariate analyses indicated a greater impact of high SDI scores (≥70, 75th percentile across all pts) in NHW (HR=1.45, p=0.068) than in NHB pts (HR=0.78, p=0.35) for OS. Adjusting for age, sex, ISS stage, and SDI, NHB did not appear to have worse OS (HR=0.75, 95% CI: 0.35-1.60; p=0.46) or PFS (HR=1.23, 95% CI: 0.78-1.96; p=0.37) compared to NHW pts. Conclusions: Our study represents a diverse population enriched for pts who received modern day standard of care frontline therapies including triplet and quadruplet regimens with or without ASCT. Based on SDI scores, higher social deprivation levels were seen in NHB compared to NHW pts without a difference in outcomes between the two races. Our analysis supports that higher social deprivation among different races rather than race and ethnicity alone may drive differential outcomes and adjustment for factors like SDI is critical to interpretation of survival outcomes by race.

Abstract Background: Multiple myeloma (MM) remains incurable, though key advances such as chimeric antigen receptor T-cells (CAR-T) and immunomodulatory agents, now evolving toward cereblon E3 ligase modulatory drugs (CELMoDs), have substantially improved the longevity and quality of life for patients (pts). Idecabtagene vicleucel (ide-cel) is a CAR-T targeting B-cell maturation antigen (BCMA), now US FDA-approved for pts who have received ≥2 prior lines of therapy including a proteasome inhibitor, immunomodulatory agent, and CD38 monoclonal antibody. Ide-cel was initially FDA-approved for ≥4 prior lines of therapy based on the KarMMa-1 study, which demonstrated a median progression-free survival (PFS) of 8.8 months across all cell doses and median overall survival (OS) of 19.4 months (Munshi et al., New Eng J Med 2021). Although promising, the fact that virtually all pts relapse post-ide-cel indicates that further progress is needed. To that end, iberdomide is an investigational CELMoD that in combination with dexamethasone has demonstrated a 30% response rate in early phase studies of triple class-refractory MM (Lonial et al., Lancet Haem 2022). Additionally, in laboratory-based correlative studies, iberdomide, at doses of ≤1 mg (well below the recommended phase 2 dose of 1.6 mg) was shown to augment immune function, including enhanced T-cell activation and cytotoxicity, and modulation of the cytokine milieu (Amatangelo et al., Cell Rep Med 2024). Iberdomide's combined properties of direct MM cytotoxicity and T-cell potentiation have clear, potential relevance to CAR-T clinically, providing the conceptual basis for the CADMIUM study (NCT06179888), exploring the effects of iberdomide as post-ide-cel maintenance therapy in MM. Study Design and Methods: This is a randomized phase II trial with a safety run-in to evaluate if treatment with iberdomide maintenance post-ide-cel can significantly improve PFS vs. standard of care (SOC) observation without therapy, in pts with relapsed/refractory MM with ≥4 prior lines of therapy, who have received ide-cel within 3 months of registration, and no evidence of MM progression or additional MM therapy since ide-cel. Pre-ide-cel iberdomide exposure is permissible but refractoriness is not. The safety run-in will confirm tolerability of the iberdomide dose to be carried forward, where doses to be tested include: iberdomide 1 mg orally on days 1-21 of a 28-day cycle (dose level 1; DL1) and iberdomide 0.7 mg on days 1-21 of a 28-day cycle (DL2). Dose-limiting toxicities (DLTs) include any of the following during the DLT period of a pt's first three months on iberdomide: prolonged Grade 3 non-hematologic toxicities, Grade 4 non-hematologic toxicities, prolonged Grade 4 neutropenia or thrombocytopenia, or any adverse event requiring iberdomide interruption for >4 weeks. Six pts will be enrolled onto DL1; if at most 1 of these pts has a DLT, DL1 will be carried forward to the randomized part of the study. Otherwise, 6 pts will be enrolled onto DL2. The randomized part of the trial will randomize 60 pts 1:1 to either iberdomide or SOC observation without therapy. A 1-sided log-rank test with α=0.15 has 81% power to detect a true hazard ratio (iberdomide/SOC) of 0.55 or less, corresponding to an improvement in median PFS to 16 vs. 8.8 months with SOC. One interim analysis for futility is planned. Secondary outcomes include OS, best response by International Myeloma Working Group (IMWG) criteria, and deepening of response, particularly conversion to complete response with a bone marrow minimal disease-negative state by Adaptive clonoSEQ (sensitivity 1e-6). Robust correlative studies will include CAR-T persistence, assays of T- and other immune cell function, and pathological analyses of whether BCMA expression on MM cells (prior to enrollment or at relapse) or other markers predict clinical outcomes. Study status: To date, 12 pts have been screened, with 7 pts enrolled on study as part of the safety run-in (1 patient replaced). Enrollment data will be updated at presentation. Notably, an amendment is forthcoming which will enhance correlative studies and broaden eligibility criteria to include patients who have received ≥2 prior lines of therapy, conforming with ide-cel's current FDA label. Study COI: BMS is supporting correlative studies. Study Support: U10CA180821, U10CA180882; BMS; U10CA180868 (NRG Oncology); http://acknowledgements.alliancefound.org

Abstract Background Translocation of chromosomes 4 and 14 (t(4;14)) results in overexpression of MMSET and has been associated with poor clinical outcomes in patients (pts) with multiple myeloma (MM). KTX-1001 is a first-in-class, potent, and selective oral inhibitor of MMSET (also known as NSD2) developed as the first investigational therapy to directly target the high-risk t(4;14) translocation, a key molecular driver in MM. KTX-1001 binds to and inhibits the catalytic SET domain of MMSET, thereby suppressing the deposition of dimethylated histone H3 lysine 36 (H3K36me2), leading to downregulation of oncogenic histone modifications and epigenetic reprogramming of malignant plasma cells. Preclinically, KTX-1001 synergistically inhibited cell viability in MM cell lines when combined with a proteasome inhibitor (PI), immunomodulatory drug (IMiD), or cereblon E3 ligase modulator (CELMoD™). Preliminary findings were previously reported from the initial cohort of 18 pts enrolled in a first-in-human phase 1 trial evaluating KTX-1001 in relapsed/refractory multiple myeloma (RRMM; NCT05651932; Bories et al. Blood. 2024;144[Suppl 1]:3370). Here, we present updated results from this study. Methods RRMM pts who received ≥3 prior therapies, including PI, IMiD and anti-CD38 monoclonal antibody (anti-CD38 mAb), received oral KTX-1001 across 9 dose levels using a 3+3 dose-escalation design. Primary objective was to determine the recommended Phase 2 dose (RP2D) and the maximum tolerated dose (MTD). Secondary objectives included pharmacokinetics, pharmacodynamics (PD), and primary efficacy. The dose expansion phase has been initiated to evaluate KTX-1001 in combination with either carfilzomib or the investigational CELMoD™ mezigdomide in t(4;14) RRMM pts. Results As of 13 June 2025, 40 pts have been treated in the monotherapy dose-escalation phase. The maximum tolerated dose (MTD) was exceeded due to dose-limiting toxicities (DLTs) in 2 pts: two Grade (Gr) 4 thrombocytopenia and one Gr 3 epistaxis. Backfill at selected dose levels is ongoing to further characterize safety profile and refine dose optimization. The median time from initial MM diagnosis was 8 years (range:2-20) with a median of 6.5 prior lines of therapy (range: 3-25). This included stem cell transplant (70%), BCMA CAR-T (42.5%), and non-CAR-T BCMA targeted drugs such as antibody-drug conjugates and bispecific antibodies (57.5%). The median age was69 years (range:50-83); 21 were female and 19 were male. Extra-medullary disease was present in 13 (32.5%) pts. Nineteen (47.5%) pts had t(4;14) translocation, 5 (12.5%) had 1q21 gain and 4 (10%) had deletion 17p. A total of 16 (40%) pts have shown a treatment response according to IMWG criteria or have achieved stable disease: 1 VGPR (10+ months), 1 PR (4+ months), 2 MR (3+ and 12 months), 12 SD (2-20+ months). KTX-1001 has demonstrated a favorable tolerability profile. Grade 3 or higher treatment-emergent adverse events (TEAEs) were reported in 31 (77.5%) pts. The most frequent (≥20% pts) Gr 3/4 TEAEs were thrombocytopenia in 12 pts (30%; grade 4 in 8 [20%]), neutropenia in 12 pts (30%; febrile neutropenia in 2 [5%]), anemia in 10 (25%) pts. Gr 3 infections were observed in 5 (12.5%) pts and fatigue in 5 (10%) pts. The main reason for treatment discontinuation was progressive disease (57.5%), other pts discontinued due to physician decision (5%), consent withdrawal (5%), and one pt due to adverse event. Twelve (30%) pts remain on treatment. At Cycle 1 Day 15, drug exposure and steady-state concentrations of KTX-1001 increased with dose. A dose-dependent reduction in H3K36me2, the primary PD marker of KTX-1001 activity, was observed in peripheral blood at Cycle 2 Day 1 and beyond, which plateaued above dose-level 4. Paired bone marrow samples further confirmed on-target PD effects, with a marked reduction in H3K36me2 levels in MM cells at Cycle 2 Day 1 with observed anti-MM effect of reduced proliferation of MM cells with concomitant increased proliferation in immune cells in pts achieving clinical benefit. ConclusionsKTX-1001 is a novel agent showing tolerable safety profile in RRMM and demonstrating promising single agent activity in heavily pretreated, triple class refractory RRMM including those with high-risk features. KTX is currently evaluated in ongoing study in combination with carfilzomib and the investigational CELMoD™ mezigdomide in t(4;14) RRMM pts.

Abstract Consumption of a Western diet and high body mass index (BMI) are risk factors for progression from premalignant phenotypes to multiple myeloma, a hematologic cancer. In the NUTRIVENTION trial (NCT04920084), we administered a high-fiber, plant-based diet (HFPBD; meals for 12 weeks, coaching for 24 weeks) to 23 participants with myeloma precursor states and elevated BMI. The intervention was feasible and improved quality of life and modifiable risk factors: metabolic (BMI, insulin resistance), microbiome (diversity, composition), and immune (inflammation, monocyte subsets). Disease progression trajectory improved (n = 2) or was stable. Findings were translated to Vk*MYC mice modeling the myeloma precursor state, in which a high-fiber diet (HFD) delayed disease progression through improved metabolism and microbiome composition, leading to increased short-chain fatty acid production that reinvigorated antitumor immunity and inhibited tumor growth. These effects from fiber consumption were independent of calorie restriction and weight loss. A HFD is a low-risk intervention that may delay progression to myeloma. Significance: A HFPBD in participants with precursor plasma cell disorders and an elevated BMI improved metabolic, microbiome, and immune biomarkers of disease. In a subset, it may delay progression to myeloma. In mouse models, a HFD delayed progression to myeloma independent of calorie restriction. See related commentary by Fairfield and Reagan, p. 623

Multiple myeloma (MM) is consistently preceded by monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM). While these precursor conditions are asymptomatic, they are not entirely benign and carry a lifelong risk of progression to MM. Unlike other cancers defined by pathology, malignant transformation from MGUS or SMM to MM has so far relied on demonstration of clinical end-organ damage as morphology and cytogenetics cannot reliably distinguish them. In this study, using genomic data from 374 patients with MGUS or SMM (277 training, 97 validation), to our knowledge, we demonstrate for the first time the ability to identify malignant transformation in MGUS and SMM. We introduce the concept of genomic MM and genomic MGUS to differentiate the subsets of MGUS and SMM that are biologically malignant with genomic features indistinguishable from MM from the subset that is premalignant and unlikely to progress to malignancy. Importantly, we find that most SMM has biological features of malignant transformation indistinguishable from MM. As expected, this subset that we consider having genomic MM is associated with a high risk of progression to MM although some patients remained progression-free beyond 5 years. Conversely, 60% of MGUS and 10% of SMM have no evidence of malignant transformation (genomic MGUS), with no progression during follow-up. Integration of genomic features with the 2/20/20 International Myeloma Working Group model significantly improved the prediction of progression among genomic MM. These findings support the use of genomic criteria to refine the classification and the risk stratification in myeloma precursor conditions.

Background. The spirometric response to standard-of-care (SOC) immunosuppressive therapy for the management of bronchiolitis obliterans syndrome (BOS) has been sparsely reported in the literature. Data from a Medicare-approved Registry were analyzed to characterize the effectiveness/durability of a wide range of SOC interventions to manage the decline of lung function and to validate the study spirometric criteria for initiation of rescue therapy. Methods. Lung transplant recipients with refractory BOS at 21 US collaborating centers were enrolled in the Registry. Data included both nonspirometric (eg, demographic, Immunosuppressive Regimens for management of BOS) and spirometric parameters (ie, forced expiratory volume in 1 s [FEV 1 ] measurements and derived indices). The utility of study FEV 1 criteria for treatment (ie, statistically significant rate of FEV 1 decline >30 mL/mo) was evaluated by comparing the spirometric course between participants who met or did not meet this criterion. Results. Only 21% of participants treated with SOC therapy had >50% decrease (76 ± 25% decrease) in the rate of FEV 1 decline. Although 51% of participants had a partial response (rate of FEV 1 decline decreased on average 71%), 49% of participants had a substantial increase (mean increase 224%). The FEV 1 criterion for treatment was able to identify 19% of participants (48/258) who achieved durable stabilization (ie, nonsignificant rate of FEV 1 <30 mL/mo) with SOC therapy. Conclusions. Patients with BOS have a widely variable response to SOC therapy. Our findings support the use of FEV 1 rate of decline to assess response to SOC therapy and to ensure appropriate assignment of participants with refractory BOS to rescue therapy treatment cohorts.

BACKGROUND. We developed a prospective, multicenter “registry” to evaluate the effect of extracorporeal photopheresis for lung transplant recipients who develop chronic lung allograft dysfunction (CLAD) with the bronchiolitis obliterans syndrome (BOS) phenotype (CLAD/BOS) and who are refractory to conventional standard-of-care therapy. METHODS. Data from 258 lung transplant recipients enrolled in the Registry between April 2015 and April 2022 were included in this analysis. All recorded parameters (eg, demographics), including forced expiratory volume in 1 s (FEV1) measurements and indices (FEV1% baseline, FEV1 rate of decline) at several time periods, were included in multivariate linear/logistic and Kaplan-Meier analyses to evaluate potential associations with survival. RESULTS. Mortality at 6 and 12 mo after CLAD/BOS diagnosis was 5% and 14%, whereas mortality at 6 and 12 mo after enrollment was 15% and 26%, respectively. The primary cause of death in the cohort was respiratory failure or graft failure (74%). Rate of FEV1 decline (log) at enrollment was independently associated with survival (log days) from CLAD/BOS diagnosis and enrollment (r = 0.55 and r = 0.3, respectively). The rates of FEV1 decline among survivors were lower (–77 ± 89 mL/mo) compared with nonsurvivors (–148 ± 155 mL/mo) at 6 mo after enrollment (P = 0.0001). CONCLUSIONS. The rate of FEV1 decline quantified using at least 5 FEV1 measurements is a robust surrogate outcome. We plan to use these findings to revise our randomized controlled trial to facilitate risk adjustment using FEV1 rate of decline strata at enrollment and as a scientifically valid surrogate for outcome.

Background: Studies have suggested a synergism between lenalidomide (LEN) and ibrutinib (IBR) in multiple myeloma (MM). Both downregulate IRF4, a key target and master transcriptional factor regulating myeloma cell survival. Method: A 3 + 3 phase I trial was conducted to determine the maximum tolerated dose (MTD) of IBR in combination with LEN + dexamethasone (DEX) in patients with relapsed/refractory (RR) MM who had at least one prior line of therapy. Three dose levels (DLs) were planned. The cycle length was 28 days. IBR was administered orally daily in doses of 560 mg on DL1-2 and 840 mg on DL3, LEN was administered orally on days 1–21 in doses of 15 mg on DL1 and 25 mg on DL2-3, and DEX was administered orally on days 1, 8, 15, and 22 in a dose of 40 mg if age < 75 years or in a dose of 20 mg if it was ≥75 years for DL1-3. Patients with a glomerular filtration rate (GFR) <60 but ≥30 mL/min were treated in accordance with the manufacturer’s instructions with LEN 10 mg. Dose-limiting toxicities (DLTs) included the following: grade 4 neutropenia lasting more than 5 days, thrombocytopenia, febrile neutropenia, nausea, vomiting or diarrhea; grade 3 thrombocytopenia with bleeding or platelet transfusion; and grade 3–4 hyperglycemia or a thrombotic/embolic event, and other nonhematologic toxicities. The overall response rate (ORR) was defined as the percentage of patients with a partial response (PR), very good partial response (VGPR), or complete response (CR) according to IMWG criteria on two consecutive evaluations at least 4 weeks apart. The clinical benefit rate (CBR) was defined as the percentage of patients with stable disease (SD) or a better outcome on two consecutive evaluations at weeks apart. Results: Fourteen patients (DL1: six patients; DL2: three patients; DL3: five patients) were registered for the study from March 2019 to May 2023, prior to its closure due to limited accrual. Thirteen patients are included in the summary of toxicities and response as one patient on DL3 halted participation prior to the start of the treatment. Two patients on DL3 were excluded from the determination of MTD: one having discontinued cycle 1 treatment due to COVID-19 infection and the another having mistakenly taken 280 mg/day of IBR instead of the assigned 840 mg/day dose during cycle 1. Only one patient developed a DLT, on DL1 with grade 3 non-viral hepatitis. The median number of cycles administered was 4 (range: 1–56). Severe toxicities reported included grade 4 lymphocytopenia (1), grade 4 thrombocytopenia (1), and grade 5 sepsis in the setting of PD (1). Disease responses included a VGPR on DL1 and CR on DL3. Thus, the ORR was 15.4% (90% CI: 2.8–41.0%). One patient on DL1 maintained SD for 4.6 years before discontinuing the treatment to undergo an alternative therapy. Another five patients maintained SD for ≥ 2 consecutive cycles. Thus, the CBR was 61.5% (90% CI: 35.5–83.4%). Conclusions: The combination of LEN with IBR in RR MM proved feasible, with manageable toxicities and the majority of discontinuations being due to disease progression.