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Abstract INTRODUCTION Allogeneic hematopoietic cell transplantation (alloHCT) is indicated in patients (pts) with FLT3-ITD mutated AML. The randomized BMT CTN 1506 trial (Levis et al. JCO) demonstrated that maintenance with FLT3 inhibitor gilteritinib (gilt) significantly improved relapse-free survival (RFS) among pts with detectable peri-alloHCT minimal residual disease (MRD) but was also associated with a greater degree of myelosuppression and infections. In older pts, aged >60 years, increasing post-HCT toxicity may adversely impact outcomes. On this basis, we performed a post-hoc analysis of pts aged > 60 years enrolled onto BMT CTN 1506 to examine the impact of gilteritinib maintenance in older pts. METHODS Pts ≥60 years randomized on BMT CTN 1506 (gilt=47, placebo=57; N=104) were included. The primary endpoint of this post-hoc analysis was RFS. We additionally assessed overall survival (OS), incidence of relapse, non-relapse mortality (NRM) in all pts and in pts with detectable MRD. RESULTS Baseline characteristics were balanced. Age was similar (65.2 vs 64.7 years; p = 0.12), as was prior TKI exposure, and NPM1 mutation status. Myeloablative conditioning (MAC) was used in 8 (17%) pts randomized to gilt and 18 (32%) pts randomized to placebo (p=0.08). Median f/u of survivors was 43.8 months (range:1-61 mo.). Estimated RFS and OS at 48 months were not different between groups (RFS: gilt: 57.0%, 95%CI 44.1-73.7%, placebo: 57.1%, 95%CI 45.4-71.8%; OS: gilt: 56.9%, 95%CI 42.9-46.7%, placebo: 58.4%, 95%CI 46.7-73.1%). While gilt assignment did not affect survival, several predictors of poorer survival were identified including use of reduced intensity conditioning (RIC) (HR = 3.46; p = 0.014), use of calcineurin inhibitor/MTX for graft-vs-host disease (GVHD) prophylaxis (HR = 2.29; p = 0.041), high-risk cytogenetics (HR = 2.64; p = 0.021), and MRD (+) pre-HCT (HR = 2.29; p = 0.018). Finally, relative to gilt assignment, opposing rates of relapse and NRM were observed. The incidence of relapse was lower with gilt (16%, 95%CI 6.8-28% vs 32%, 95%CI 20-45%, p=0.046) but NRM was higher (27%, 95%CI 15-41% vs 11%, 95% CI 4.3-21%, p=0.033). We next analyzed the 49 pts (gilt=22, placebo=27) with detectable peri-HCT MRD. RFS and OS again were not different (RFS: gilt: 44.4%, 95%CI 27.1-72.7%, placebo: 43.8%, 95%CI 28.4-67.5%, OS: gilt: 49.2%,95%CI, 31.3-77.4%, placebo: 55.6%, 95%CI 39.4-77.8%). The incidence of relapse trended lower in gilt pts (25%, 95%CI, 5.3-44.7% vs 45% (95%CI, 25-63%), p=0.2) while NRM trended higher (31%, 95%CI 12-52% vs 11%, 95%CI, 2.7-26%, p=0.12). Seventeen (36%) patients completed planned 2 year maintenance with gilt compared to 29 (51%) completing therapy with placebo. Median time on gilt was 13.2 months. The most common reason for discontinuation was adverse events (n=19, 40%), of which cytopenias (n=8) and infections (n=4) were most frequent. Non-relapse causes of death among gilt treated pts included infections (n=8), intracranial hemorrhage related to thrombocytopenia (n=1), second cancer (n=1), and Guillain-Barre syndrome (n=1). Most infections (n=5) were attributed to GVHD as an underlying cause. CONCLUSION Among pts aged ≥60 years, gilt maintenance did not improve RFS or OS. Gilt use was associated with reduced relapse regardless of peri-HCT MRD status demonstrating disease effect; however, higher NRM limited overall benefit. In older FLT3 mutated pts, employing strategies to mitigate HCT related toxicity, e.g. alternative GVHD prophylaxis strategies, may better accommodate use of maintenance therapy including gilt. Lower doses of gilt (particularly with azole co-use) may be worth exploring to mitigate drug AEs, improve compliance, thus further improving benefit.

Abstract Background and Significance Diffuse large B-cell lymphoma (DLBCL) and other LBCLs account for 35–40% of non-Hodgkin lymphoma cases in North America, Europe, and East Asia. Rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) is the standard first-line treatment for DLBCL, achieving cure rates in approximately 60–70% of patients. However, 30–40% of patients will relapse or become refractory (R/R) to treatment, facing poor prognosis. Patients with high International Prognostic Index (IPI) scores (3–5) and those with IPI 1–2 who have bulky disease and/or very high lactate dehydrogenase (LDH) are recognized as high-risk (HR) subsets with suboptimal outcomes (Maurer et al, ASH 2023, #4512). Novel combination strategies are an area of focus for improving efficacy in this population. GOLCA is a potential, first-in-class, oral CELMoD agent designed for the treatment of lymphoma, with preferential distribution to lymphoid organs and enhanced activity in lymphoma cell lines. GOLCA drives the closed, active conformation of cereblon to induce rapid and deep degradation of Ikaros and Aiolos, leading to direct cell killing (agnostic of cell of origin [COO]) and immunomodulatory activity. In the Phase 1b study CC-220-DLBCL-001, GOLCA in combination with R-CHOP demonstrated a predictable and manageable safety profile with high rates of durable responses, irrespective of COO, in previously untreated aggressive B-cell lymphomas (BCL), including promising activity in HR patients (Amzallag et al, ASH 2024, #579). The median relative dose intensity for GOLCA and CHO components was high (97–99%), indicating uncompromised delivery of curative standard-of-care treatment and combinability. GOLCA ± rituximab has also shown encouraging efficacy and safety in patients with R/R DLBCL (Bachy et al, ICML, #148). These findings support the further study of GOLCA + R-CHOP combination in the Phase 3 setting. Study Design and Methods GOLSEEK-1 (NCT06356129) is a randomized, double-blind, placebo-controlled, Phase 3 study evaluating GOLCA + R-CHOP versus placebo + R-CHOP in patients with previously untreated HR LBCL. Approximately 850 patients with previously untreated LBCL will be randomized 1:1 to either GOLCA + R-CHOP or placebo + R-CHOP. Eligible patients include those with histologically confirmed LBCL per WHO 2022 criteria—including DLBCL (not otherwise specified [NOS], ABC/GCB), high-grade BCL with MYC and BCL2 rearrangements or NOS, T-cell/histiocyte–rich LBCL, or Epstein Barr Virus-positive DLBCL. HR status is defined by IPI ≥3, or IPI 1–2 with HR features: LDH >1.3× upper limit of normal and/or bulky disease (≥7 cm lesion). All patients must have measurable disease as defined by Lugano criteria. Key exclusion criteria are other lymphoma subtypes such as primary mediastinal LBCL; primary cutaneous DLBCL-leg type, grade 3b follicular lymphoma (FL); transformed indolent lymphoma; anaplastic lymphoma kinase (ALK) positive LBCL; primary effusion lymphoma; and Burkitt lymphoma and known or suspected central nervous system involvement. Randomization will be stratified by IPI score (HR 1–2 and 3 vs 4–5) and bulky disease status (≥7 cm vs <7 cm). After a screening period of ≤4 weeks, patients will receive either GOLCA (0.4 mg) or placebo orally once daily for 7 consecutive days in each of 6 cycles, combined with R-CHOP every 21 days. The primary endpoint is progression-free survival (PFS) by investigator assessment per Lugano Response Criteria. Key secondary endpoints include PFS in non–high-grade BCL, event-free survival, independently assessed complete metabolic response, undetectable minimal residual disease by PhasED-Seq (defined as undetectable circulating tumor DNA levels at end of treatment), and overall survival. Patients will be followed up for up to approximately 67 months after beginning treatment. This study is currently recruiting at 309 sites in 36 countries , across the United States, Europe, Latin America, and East Asia. Acknowledgement BMS Artificial Intelligence was used to revise existing text with human author oversight.

Abstract Background Adult xanthogranuloma (AXG) is a rare clonal histiocytic neoplasm (HN) with a poorly defined mutational landscape. Clinically and immunophenotypically, AXG can resemble other HNs such as Erdheim-Chester Disease (ECD) which frequently harbor MAPK pathway alterations and carry BRAF V600E mutations in close to 50% of cases. However, due to the rarity of AXG, the prevalence of the BRAF V600E mutation and the broader mutational landscape is not well known. In this study, we characterize the mutational profile of AXG. Methods We conducted a retrospective analysis of patients diagnosed with AXG at our institution between January 1, 2016, and July 15, 2025. The study was approved by the institutional review board. To ensure inclusion of true AXG cases, only patients with a confirmed histopathologic diagnosis and without multisystemic involvement or characteristic imaging findings of ECD, such as symmetric long bone osteosclerosis, were included. BRAF alterations were identified by immunohistochemistry (IHC) and/or next-generation sequencing (NGS). We also performed an extensive literature review of mutational studies in AXG and included cases that underwent comprehensive NGS. Results Seventeen patients with AXG were identified. The median age at diagnosis was 40 years (range: 18–75 years). Out of the 17 patients, 11 (65%) reported the face as the primary site of disease, and 11 (65%) had solitary lesions. Of the 17 patients, 13 (76%) underwent BRAF V600E IHC staining, and none tested positive. Twelve (71%) patients had tissue samples analyzed via NGS, and none exhibited the BRAF V600E mutation. Eight of the 12 (67%) patients with NGS testing harbored other alterations involving the MAPK pathway. These included BRAF fusions (n=3), KRAS mutations (n=2), and individual cases with TRAF7 mutation, ALK1 fusion and FGFR1 fusion. One patient was found to have a mutation in WRN, which is not previously reported in AXG. Three patients had no identifiable pathogenic alterations on NGS. Ten patients were monitored without treatment, 2 underwent surgical resections and 3 received chemotherapy (1 had a complete response [CR], 2 achieved a partial response). One patient with FGFR1 fusion was treated with pemigatinib and achieved a CR for over 3 years. One patient with TRAF mutation obtained a CR after treatment with rituximab. We also identified 51 cases of AXG with adequate mutational testing reported in the literature, which reported findings similar to ours. In a retrospective study from France involving 29 patients, MAPK alterations were observed in 55% of cases: however, only 10% harbored BRAF V600E mutations (1). Another analysis of 270 patients with various HN subtypes included 13 individuals with AXG, none had BRAF mutations. MAP2K1 mutations were seen in 31% of patients (2). Taken together, across a combined cohort of 68 AXG patients, the most common alterations were: KRAS mutations (16%), fusions (14%), MAP2K1 mutations (7%) and BRAF V600E (6%). Among fusions, the most involved gene was BRAF (50%), and GAB2 was the most common fusion partner (n=2). In total, 59% of patients had MAPK alterations. These findings collectively underscore the diverse mutational landscape of AXG and highlight the rarity of BRAF V600E mutations relative to closely related HNs. Conclusion We present a series of AXG cases with mutational profiling, from our institution and the published literature. We demonstrate that MAPK alterations are frequently observed in AXG and are driven by heterogeneous mutations. In contrast to other HNs where BRAF V600E mutations are common, we identified no such mutations in our cohort and found only rare cases in the literature. Our institutional data, along with findings from the existing literature, suggest that AXG may have a distinct molecular profile compared to other HNs. A deeper understanding of its mutational landscape may offer insights into disease biology and identify therapeutic targets. ReferencesAnnabi E, Mahévas T, Chasset et al. Clinical, Histopathologic, and Molecular Features and Treatment of Multiple Xanthogranuloma in Adults. JAMA Dermatol. 2025;161(7):765-768. doi:10.1001/jamadermatol.2025.0886.Durham BH, Lopez Rodrigo E, Picarsic J, et al. Activating mutations in CSF1R and additional receptor tyrosine kinases in histiocytic neoplasms. Nat Med. 2019;25(12):1839-1842. doi:10.1038/s41591-019-0653-6

Abstract Background:Erdheim-Chester Disease (ECD) is a rare, incurable histiocytic neoplasm. Since its recognition in 1930, our understanding of ECD's pathophysiology has evolved. The identification of its clonal nature after 2015 established ECD as a cancer, prompting increased disease awareness and treatment advances. Targeted therapies show promising responses, but changes in ECD mortality over time have not been extensively documented. Methods:A multi-institutional retrospective cohort study analyzed adults with ECD consecutively seen at Mayo Clinic MN, AZ, and FL and the University of Alabama at Birmingham between 2007 and 2024. Clinical and prognostic data were abstracted. Overall survival was estimated using the Kaplan-Meier method and compared to expected survival using U.S. Census data, based on age at diagnosis (by calendar year), date of diagnosis, and sex. Standardized mortality ratios (SMRs) were calculated by dividing the number of observed deaths in the study population by the expected number of deaths using U.S. population data. Risk of death was compared by date of diagnosis (pre- and post-2015) using Cox proportional hazards analysis. Statistical analysis was performed with R software. Results:A total of 159 ECD patients were included (median age 58 years [range 19-82], 65% male). Forty-nine patients were diagnosed between 1990-2014 and 110 between 2015-2024. Median follow-up for the entire cohort was 4.0 years (95% CI: 3.2-4.4). Median follow-up for those diagnosed between 1990-2014 was 10.4 years (CI: 3.2-16.8), compared to 3.5 years (CI: 3.0-4.2) for those diagnosed between 2015-2024. The 5-year overall survival rate was 80% (95% CI: 72-88). Patients with ECD had an increase in mortality over expected, with 28 deaths compared to an expected 11.2, an SMR of 2.5 (95% CI: 1.7-3.6, p<0.001). Of 17 patients with an identified cause of death, death was attributable to ECD in 11 (65%), secondary malignancy in 1 (7%), and unrelated causes in 5 (29%). Cause of death was unknown in 11 patients. Among deaths, 11 (39%) were treated with targeted therapy, 8 (29%) with chemotherapy, and 1 (4%) received both. One patient (4%) received steroids, 1 received immunomodulator and targeted therapy (4%), and 6 (21%) received no disease-directed therapy. Of the patients whose death was related to ECD, 10 (91%) had multisystem disease. For 49 patients diagnosed pre-2015, 14 deaths occurred during the follow-up, significantly higher than the expected 5.2 deaths based on U.S. population data (SMR of 2.7 [95% CI: 1.5-4.4, p=0.001]). Among those diagnosed between 2015 and 2024, 14 deaths occurred, compared to expected 6.1 (SMR of 2.3 [95% CI: 1.3-3.8, p=0.006]). In an age- and sex-adjusted Cox proportional hazards model, diagnosis after 2015 vs. diagnosis prior to 2015 yielded a hazard ratio of 0.59 (95% CI: 0.27-1.31, p=0.19). Conclusion:The mortality rate of ECD patients remains higher than the general population, despite advancements in disease recognition and development of targeted therapies. While our data suggest a possible trend toward improved survival among patients diagnosed after 2015, we did not find statistically significant evidence of decreased mortality compared to those diagnosed prior to 2015. Larger cohorts with longer follow-up periods are needed to draw definitive conclusions regarding mortality.

Abstract Aims BMT CTN 1506 (“MORPHO”) was a global phase 3 study of post-hematopoietic cell transplantation (HCT) maintenance with gilteritinib versus placebo for patients with FLT3-ITD-mutated AML in CR1. The study did not meet its primary endpoint of improved relapse-free survival (RFS) for post-HCT gilteritinib, but subgroup analysis indicated a benefit for participants with pre-HCT measurable residual disease (MRD). Subgroup analysis also indicated a statistically significant benefit of post-HCT gilteritinib for participants in North America, but no benefit for those in Europe or Asia. RFS for the control arms in Europe and Asia was higher than anticipated, suggesting that participants with different disease biology may have accrued to the study in these different geographic regions. In the primary analysis of the study, pre-HCT FLT3 inhibitor use and MRD across the entire study population were both found to have impacted outcomes. Time from diagnosis to HCT, a reflection of local practice patterns, is also known to impact outcomes for FLT3-ITD AML. We hypothesized that local practice patterns of pre-HCT FLT3 inhibitor use and time from AML diagnosis to HCT could have influenced the disease biology of study pts at the time of enrollment. This would be predicted to result in pre-HCT MRD levels and could provide an explanation for the regional differences observed in the study outcome. Methods We conducted a post-hoc analysis of the data focusing on days from AML diagnosis to HCT, pre-HCT FLT3 inhibitor use, and FLT3-ITD MRD assessed by a high-sensitivity assay. Eligibility requirements included FLT3-ITD-mutated AML in first remission after intensive chemotherapy and HCT occurring within 12 months of achieving remission. Patients refractory to induction therapy, or those with a history of relapse, were ineligible. Results Accrual took place in 16 different countries, with 5 countries accounting for 79.7% of the total accrual: USA 42.7%; Japan 15.7%; Korea 8.4%; UK 6.7%; Germany 6.2%; other countries 20.2%. In two countries, USA and Germany (48.9% of total enrollment), participants underwent HCT a median of 119 days after AML diagnosis, and 90.2% were treated with a FLT3 inhibitor pre-HCT. In contrast, in Japan, Korea, the UK and the other 11 countries all combined, participants underwent HCT a median of 152.5 days after AML diagnosis, and only 30.8% received any FLT3 inhibitor pre-HCT. Amongst all participants, those transplanted < 120 days from AML diagnosis and/or those treated with FLT3 inhibition pre-HCT were more likely to have improved RFS from post-HCT gilteritinib. RFS was improved with post-HCT gilteritinib in the US and Germany (HR 0.397; CI 0.220-0.718), whereas no benefit was evident in all other countries combined (HR 1.184; CI 0.685-2.048). Pre-HCT MRD levels were significantly higher (P = 0.011) in participants transplanted within 120 days from diagnosis as well as in those treated with a FLT3 inhibitor pre-HCT and also transplanted within 120 days (P = 0.019). Pre-HCT MRD was dependent on both FLT3 inhibitor use and time to HCT, as participants treated with successive courses of chemotherapy + FLT3 inhibition had successively lower MRD by the time of HCT. Conclusions The time from AML diagnosis to HCT and FLT3 inhibitor use pre-HCT both appeared to impact MRD levels immediately prior to HCT, and geographic differences in these two practice patterns likely accounted for the regional differences in benefit from post-HCT gilteritinib observed in BMT CTN 1506. Successive courses of chemotherapy without FLT3 inhibition appears to have selected a more favorable risk (e.g., MRD-lower) population for enrollment. Successive courses of chemotherapy combined with FLT3 inhibition progressively eradicated MRD, such that a majority of participants undergoing HCT after 3 or 4 courses were MRD negative and therefore unlikely to benefit from post-HCT gilteritinib. These findings have implications for clinical practice. Increasing the number of courses of chemotherapy combined with FLT3 inhibition before HCT may lower MRD sufficiently to eliminate the need for post-HCT inhibition for some patients but, alternatively, the additional delay could increase the risk of pre-HCT relapse, preventing patients from receiving HCT in first remission.

Abstract Introduction: Indolent systemic mastocytosis (ISM) is a clonal mast cell disease driven by the KIT D816V mutation in ~95% of cases and is associated with symptoms of mast cell activation and tissue infiltration. It can cause chronic, debilitating symptoms − including life-threatening anaphylaxis and impaired bone health. While historically most patients have relied on symptom-directed best supportive care (BSC) therapies, avapritinib is used as a new standard of care targeting KIT D816V, the primary driver for SM. Avapritinib is an oral, potent, selective KIT D816V inhibitor, and the first and only approved targeted therapy for adult patients with ISM in the USA and the EU. Approval was based on results from the phase 2 PIONEER trial. Here, we present the findings from ~3.5-year long-term follow-up. Methods: Adults with centrally confirmed ISM and uncontrolled moderate-to-severe symptoms who completed the randomized dose-finding (Part 1), or randomized, double-blind, placebo-controlled (Part 2) portions of PIONEER (NCT03731260) rolled over to the open-label, long-term extension (Part 3). This cumulative analysis includes patients who initiated avapritinib at the recommended dose of 25 mg once daily (QD) in either Parts 1, 2, or 3. All patients received BSC. Per investigator discretion and based on disease burden, dose titration up to 50 mg QD of avapritinib was permitted in Part 3. Long-term efficacy was assessed by measuring changes in symptoms and QoL, using the ISM-Symptom Assessment Form (ISM-SAF; ©2018 Blueprint Medicines, a Sanofi Company) and the Mastocytosis Quality-of-Life Questionnaire (MC-QoL). Safety was also assessed. Results: Overall, 226 patients initiated avapritinib 25mg QD across Parts 1, 2, and 3. This longer-term analysis is inclusive of 65 patients who dose titrated from 25 mg to 50 mg QD in Part 3. Median (range) treatment duration was 40.0 months (0.7‒67.2) as of February 21, 2025. Longer-term efficacy data with ~3.5 years of follow-up demonstrated sustained disease-related symptom improvements. The mean change (standard deviation [SD]) in total symptom score (TSS, per ISM-SAF), was −19.80 (19.81) at Week 144 (Month 33) and −20.43 (20.57) at Week 168 (Month 39) from a baseline of 48.08 (19.47). Additionally, avapritinib-treated patients demonstrated durable improvement in their most severe symptoms (mean change [SD] from baseline of −3.35 [3.02] at Month 33 and −3.47 [3.19] at Month 39) per ISM-SAF. Sustained responses were observed across all individual symptom domains (0–30) with mean changes (SD) at Month 33 and Month 39 of −3.77 (5.52) and −3.84 (6.05) for the gastrointestinal domain, −8.21 (7.70) and −8.20 (7.85) for the skin domain, and −4.66 (6.24) and −4.87 (6.51) for the neurocognitive domain. The mean percent change (SD) in MC-QoL was −34.67 (40.16) at Month 33 and −40.72 (33.24) at Month 39 from a baseline of 54.24 (18.32). Treatment with avapritinib was well tolerated, and its safety profile was similar to the previously reported placebo-controlled portion. Most treatment-related adverse events (TRAEs) were Grades 1–2, and 7% of patients experienced Grade ≥3 TRAEs of which diarrhea, neutrophil count decrease, and weight increase occurred in >1 patient. No Grade ≥3 TRAEs of increase in transaminases were observed. Edema (peripheral and periorbital), the most frequently reported TRAE, was mostly Grade 1 and occurred most frequently during the first 3–4 months of treatment. Three patients (1%) experienced serious adverse events assessed as treatment related. However, none led to treatment discontinuation and no trends were observed. After approximately 3.5 years of follow-up, low rates of treatment discontinuations (n=7, 3%) due to TRAEs were observed. Conclusion: Longer follow-up of patients with ISM treated on the PIONEER trial, including some on avapritinib for up to 5 years, demonstrates that prolonged avapritinib therapy continues to be effective and well tolerated. Additional prospective analyses will be needed to determine effects of selective KIT D816V-inhibition on anaphylaxis. These data support a favorable benefit-risk profile of avapritinib as a chronic treatment for adult patients with ISM.

Abstract Introduction Nearly 60% of pts with diffuse large B-cell lymphoma (DLBCL) are cured with first-line chemoimmunotherapy; ~40% will relapse or have refractory disease, mostly pts with high International Prognostic Index (IPI) scores of 3–5. Pts with IPI scores of 1–2 with bulky disease and/or very high LDH levels have also been identified as a high risk (HR) population (Maurer et al, ASH 2023, #4512). GOLCA is a potential, first-in-class, oral CELMoD agent designed for the treatment (Tx) of lymphoma, with preferential distribution to lymphoid organs and enhanced activity in lymphoma cell lines. GOLCA drives the closed, active conformation of cereblon to induce rapid and deep degradation of Ikaros and Aiolos, leading to direct cell killing (agnostic of cell of origin [COO]) and immunomodulatory activity. CC-220-DLBCL-001 (NCT04884035) is an ongoing Phase 1b, open-label, multicenter trial to assess safety and preliminary efficacy of GOLCA+R-CHOP in previously untreated a-BCL. GOLCA+R-CHOP demonstrated a manageable safety profile and encouraging efficacy with high end of Tx (EOT) complete metabolic response (CMR) and minimal residual disease (MRD) negativity rates (Amzallag et al, ASH 2024, #579). We report efficacy results with median follow-up (f/u) of 24 mos, including 24-mo progression-free survival (PFS) rates. Methods Pts aged ≥18 years with ECOG PS ≤2, IPI 0–5 (Part 1) and IPI 2–5 (Part 2), and previously untreated a-BCL with measurable disease were included. Pts were treated with GOLCA+R-CHOP for 6 cycles of 21 days (D) or until disease progression/unacceptable toxicity/study withdrawal. In dose escalation, GOLCA dose levels were 0.2mg D1–7, 0.4mg D1–7 (recommended Ph 2 dose), or 0.4mg D1–10. In dose expansion, pts were randomized 1:1 to R-CHOP+GOLCA 0.2 or 0.4mg. Primary endpoint was safety of GOLCA at 0.4mg (cutoff 23 Sep 2024); efficacy (cutoff 12 May 2025) was a secondary endpoint. HR pts were defined as: IPI 1-2 with HR features (≥1 lesion with maximum diameter ≥7 cm and/or screening LDH >1.3×ULN) or IPI 3–5. Results At cutoff, 78 pts were treated with GOLCA+R-CHOP (n=35 at 0.2mg D1–7, n=37 at 0.4mg D1–7, n=6 at 0.4mg D1–10). Baseline characteristics were described previously. Sixty-five pts (83%) completed Tx, and 72 (92%) entered the f/u period (61 [78%] ongoing). Tx was discontinued in 17% of pts, primarily due to progressive disease (3%) and adverse events (AEs; 6%). Median relative dose intensity for GOLCA and CHO components was high (97%–99%), indicating uncompromised delivery of curative standard-of-care (SOC) Tx. Seventy-two pts were efficacy evaluable (n=34 at 0.2mg D1–7, n=33 at 0.4mg D1–7). At 0.4mg, EOT CMR rate was 88% (29/33); all 29 pts were alive and progression free at cutoff. In HR pts at 0.4mg, EOT CMR rate was 89% (25/28) and was similar in pts with GCB (16/17 [94%]) and non-GCB/ABC (9/11 [82%]) phenotypes. Of pts treated with 0.4mg with available ctDNA data, 90% achieved MRD negativity (undetectable ctDNA by PhasED-Seq assay) at EOT. All pts still in f/u at time of data cutoff had reached the 24-mo efficacy assessment. At median f/u of 24 mos (range, 0.7–34.4), the 24-mo PFS rate was 79% in both 0.4mg and HR 0.4mg pts and consistent in pts with GCB (88%) and non-GCB/ABC (73%) phenotypes. The 24-mo OS at 0.4mg was 85.3% overall and 86.2% in HR pts. Pts treated at 0.4mg D1–7 and D1–10 had comparable exposure to GOLCA (no pt completed the 10-day schedule). In pooled D1–7 and D1–10 schedules, 24-mo PFS was 82% in overall and HR populations. Grade 3/4 Tx-emergent AEs (TEAEs) in the safety population were mainly hematologic and occurred in 91% of pts (neutropenia [87%], an on-target side effect of GOLCA; thrombocytopenia [42%]; anemia [36%]; febrile neutropenia [22%]); neutrophil nadir and recovery occurred in a predictable fashion. Serious TEAEs occurred in 36 pts (46%). Non-hematologic AEs (fatigue, rash, GI disorders) were infrequent and mostly low grade. Conclusions GOLCA (0.4mg) +R-CHOP resulted in a high rate of durable CMRs, irrespective of COO, and promising 24-mo PFS in the overall and HR populations. GOLCA+R-CHOP demonstrated a predictable and manageable safety profile with low rates of non-hematologic AEs; addition of GOLCA to R-CHOP did not compromise SOC delivery. These data continue to show that GOLCA 0.4mg, when added to SOC Tx, has a potential to cure more previously untreated pts with HR LBCL and support the ongoing Phase 3 trial, GOLSEEK-1, in this population (NCT06356129).

Abstract Introduction Approximately 40% of patients with DLBCL will experience relapse after initial treatment with standard-of-care chemo-immunotherapy. Effective treatment options are limited for patients who experience first-line treatment failure, particularly for those with R/R disease following CAR T-cell therapy or those not able to receive CAR T-cell therapy (Sehn et al, N Engl J Med. 2021). GOLCA is a potential, first-in-class, oral CELMoD agent designed for the treatment of lymphoma, with preferential distribution to lymphoid organs and enhanced activity in lymphoma cell lines. GOLCA drives the closed, active conformation of cereblon to induce rapid and deep degradation of Ikaros and Aiolos, leading to direct cell killing (agnostic of cell of origin) and immunomodulatory activity. In the two-part, multicenter, first-in-human Phase 1/2 study (CC-99282-NHL-001; NCT03930953), GOLCA was well tolerated and effective in patients with R/R DLBCL (Bachy et al, ICML 2025, #148). Here, we provide longer follow-up in patients with R/R DLBCL from Part B of the study. Methods Patients with R/R DLBCL and disease progression after ≥ 2 lines of therapy or transplant-ineligible patients after ≥ 1 line of therapy were included in the study. Patients received GOLCA monotherapy orally, once daily at different dosing schedules in Part A. In Part B, GOLCA was dosed at 0.2 or 0.4 mg (14 days on/14 days off) ± R. Total GOLCA treatment duration was up to 2 years or until progressive disease (PD)/unacceptable toxicity. Primary objectives included safety and recommended Phase 2 dose determination. Results As of April 3, 2025, a total of 77 patients with R/R DLBCL were enrolled in Part B Cohort C (GOLCA 0.2 mg + R, n = 39; GOLCA 0.4 mg + R, n = 38). Median age was 66 years (range, 20–86). Patients were heavily pre-treated; median number of prior treatments was 4 (range, 1–11), 55% of pts had prior CAR T-cell therapy, 38% had prior bispecific antibody treatment, and 44% were refractory to last treatment. Ten patients (13%) were ongoing, 4 completed 2 y of treatment, and 63 (82%) had discontinued treatment, mostly due to PD (n = 48 [62%]). The most common any-grade (G) treatment-emergent adverse events (AEs) in the 0.2- and 0.4-mg cohorts, respectively, were neutropenia (54% and 84%), an on-target side effect of GOLCA, and anemia (44% and 45%). G3/4 neutropenia was reported in 49% of patients with 0.2 mg and 79% with 0.4 mg, and febrile neutropenia (FN) in 5% and 16%, respectively. Granulocyte colony-stimulating factor was used in 81% and 88% of patients with neutropenia and 50% and 100% of patients with FN in the 0.2-mg and 0.4-mg cohorts. Dose interruptions (mainly due to infections/neutropenia) occurred in 49% and 53% of patients and discontinuations due to AEs occurred in 10% and 3% with 0.2 and 0.4 mg. One G5 pneumonia was considered related to study treatment (0.2 mg). The median follow-up was 11.8 months (range, 3.1–35.1) with 0.2 mg and 16.2 months (range, 3.8–31.4) with 0.4 mg. The overall response rate (ORR) in efficacy evaluable patients was 34% (complete response rate [CRR], 20%) with 0.2 mg (n = 35) and 58% with 0.4 mg (n = 36), including a CRR of 44% with this dose. In patients with prior T-cell–redirecting treatment, the ORR was 33% (CRR, 22%) with 0.2 mg (n = 18) and 56% (CRR, 38%) with 0.4 mg (n = 16). Seven of 35 (0.2 mg) and 14 of 36 (0.4 mg) patients experienced durable response > 12 months. The median time to response with both 0.2 and 0.4 mg was 1.8 months. In patients with durable responses (remained in response [CR or partial response] for more than two consecutive efficacy assessments) to GOLCA, circulating tumor DNA reduction from baseline continues to deepen over time. Response was similar across clones/tumor variants. Conclusions With additional follow-up, GOLCA + R continued to demonstrate a predictable and manageable safety profile, with no new safety signals observed at longer follow-up. Durable responses were shown in heavily pretreated patients with R/R DLBCL, including those with prior T-cell–redirecting therapy. GOLCA + R induced a decrease in circulating tumor DNA across tumor variants. These data support the ongoing development of GOLCA + R in patients with R/R non-Hodgkin lymphoma.

Abstract Introduction The monoclonal gammopathies of renal significance (MGRS) are defined by the presence of a nephrotoxic monoclonal protein in the absence of a well-defined malignant entity. Mechanistically it has been postulated that, across the varied subtypes of MGRS, abnormal plasma cell or B-cell clones in the marrow produce nephrotoxic proteins; however, in many cases, no paraprotein is detected by conventional laboratory methods and the bone marrow can be morphologically normal. The genomic underpinnings of MGRS are unexplored and, due to the rarity of this disease, clinicians are often left to unable to determine the exact nature of the clonal cell populations. We carried out a pilot study to characterize ctDNA in MGRS patients (pts). The first phase of the protocol sought to collect peripheral blood samples and, when possible, matched bone marrow aspirates, from MGRS pts to evaluate the feasibility of ultra-low pass whole genome sequencing (ULP-WGS) from peripheral blood to identify and characterize ctDNA. Methods We report ULP-WGS results from peripheral blood samples in the initial phase of the study. Peripheral blood samples were collected from renal biopsy proven non-amyloidosis MGRS pts prior to the initiation of treatment. Cell free DNA (cfDNA) was extracted and quantified. A total of 5-20 ng of cfDNA input was used for ULP-WGS. Libraries were pooled and sequenced using 100-bp paired-end runs to an average genome-wide coverage of 0.5x. After deconvolution and alignment, fragments with size 90-150bp were extracted using samtools. IchorCNA was utilized to calculate tumor fraction based on a panel of normals derived from three plasma samples from healthy controls. Model parameters were optimized for low tumor fraction and a threshold of 3% ctDNA was used to identify positive samples. Renal responses were assessed based on International Kidney and Monoclonal Gammopathy (IKMG) group criteria. Results Nine pts and were consented and gave samples for the study along with 3 healthy controls. Seven pts were sequenced, 4 of which were females and 3 were males. Median age was 58 years. Among sequenced pts, 5 presented with proliferative glomerulonephritis with monoclonal immune deposition (PGNMID) and 2 with light chain deposition disease (LCDD). Both patients with LCDD were kappa predominant and showed detectable plasma clones (8% and 3%). One of these pts displayed t(11:14) on bone marrow FISH testing. Among the 5 pts with PGNMID, 3 had IgG kappa deposition and only one had a detectable plasma clone (5%), which harbored trisomy 9 by FISH. Bone marrow flow cytometry was positive in 2 pts. Median 24-hour urine protein content was 7.11g (0.92 – 10.58), median serum albumin 3.20 g/dL (2.90 – 4.90) and median serum creatinine at the time of diagnosis was 2.15 mg/dL (1.30-6.40). CKD was present in 6 of 7 pts at the time of diagnosis. Four pts had known hypertension. One exhibited a history of malignancy and one had a history of autoimmune disease. ctDNA was detectable at a threshold of > 3.0% of cfDNA in 5 of 7 pts. Median ctDNA content was 4.0% (3.18% - 14.97%) of cfDNA. Four of the 5 samples containing ctDNA were hyperdiploid. Chromosome 19 was the most common site of copy number increase whereas chromosomes 6, 10, and 18 exhibited the most frequent decreases in copy number. Two pts with PGNMID had detectable ctDNA without evidence of a serological or marrow-based clone. All pts received daratumumab, cyclophosphamide, bortezomib and dexamethasone as initial treatment. Five pts responded to therapy. Two patients ultimately underwent autologous stem cell transplant and a single patient received venetoclax as second line therapy. Of the patients exhibiting detectable ctDNA, three did not exhibit renal response to initial treatment. Both pts without ctDNA had PGNMID and responded to frontline treatment. Mass spectrometry analysis and deep targeted sequencing of bone marrow aspirates and peripheral blood will be presented. Conclusions To our knowledge, this is the first study to detect ctDNA in MGRS. ULP-WGS, when combined with targeted sequencing and diagnostic modalities such as mass spectrometry, has the potential to not only to aid in diagnosis and treatment selection on a practical basis, but also to begin to unravel the underlying genomics of this rare disease. This approach has potential to serve as a platform for further genomic exploration and biomarker development in MGRS.