Sudhindra, Akshay

e19046 Background: While outcomes in pts with R/R FL have improved with current SOC treatments (Tx), there remains a need for safe, efficacious, and convenient Tx options. GOLCA is a potential, first-in-class, oral CELMoD designed for Tx of lymphoma, with preferential distribution to lymphoid organs and enhanced activity in lymphoma cell lines. GOLCA induces rapid and deep degradation of Ikaros and Aiolos, leading to direct cell killing and immunomodulatory activity. GOLCA + R was well tolerated and effective in heavily pretreated pts in the two-part Ph 1/2 study, CC-99282-NHL-001. Here, we provide longer f/u in pts with R/R FL from Part B of the study. Methods: Pts with R/R FL with ≥2 prior lines of Tx (≥1 if prior anti-CD20 Tx) received GOLCA orally, once daily at 0.2 mg (n=22) or 0.4 mg (n=38) ± R for up to 2 y or until progressive disease (PD)/unacceptable toxicity. Primary endpoints included safety and RP2D determination; secondary endpoints are preliminary efficacy and PK. Results: As of September 15, 2025, 60 pts were enrolled. In 0.2 and 0.4 mg groups, median prior Tx lines were 3 and 3, 32% and 32% had prior lenalidomide (LEN), 27% and 29% had prior T-cell–redirecting Tx (CAR T and/or bispecific antibody) and 32% and 32% were refractory to last regimen. Tx is ongoing in 6 (27%) and 17 (45%) pts at 0.2 and 0.4 mg, respectively; discontinuations (d/c) were mostly due to PD. Neutropenia, an on-target side effect of GOLCA, was the most common grade 3/4 Tx-emergent adverse event (TEAE) occurring in 59% and 68% of pts at 0.2 and 0.4 mg, followed by anemia (9% and 16%) and febrile neutropenia (9% and 8%). Median time to resolution of neutropenia was 8 days. Dose reductions occurred in 14% and 37% of pts at 0.2 and 0.4 mg, most commonly due to neutropenia (5% and 21%) and febrile neutropenia (5% and 5%). No d/c or deaths were from GOLCA-related TEAEs. Non-hematologic TEAEs were infrequent and mostly low grade. In efficacy-evaluable pts (GOLCA 0.2 and 0.4 mg + R, n=22 and n=36), median f/u was 14.03 months (mo), overall response rate (ORR) was 77% (complete response rate [CRR], 41%) at 0.2 mg, and 97% (CRR, 78%) at 0.4 mg. In the 0.4 mg group, responses were consistent in high-risk subsets including pts with prior LEN (ORR, 100%; CRR, 75%) and/or T-cell–redirecting Tx (ORR, 91%; CRR, 64%). GOLCA 0.4 mg + R demonstrated durable responses (median DOR, 9.17 mo; 91% of pts who achieved a CR remained in CR at cutoff). Conclusions: With longer f/u, GOLCA + R demonstrated promising efficacy with durable responses and no new safety signals. The 0.4 mg group had higher ORR and CRR than 0.2 mg, including in pts with prior LEN-based and/or T-cell–redirecting Tx, with a manageable safety profile at both doses. The results support the development of GOLCA + R as a fixed-duration, chemotherapy-free outpatient Tx in the Ph 3 GOLSEEK-4 study in 2L+ FL (NCT06911502). Clinical trial information: NCT03930953 .

Abstract Introduction While outcomes in patients with R/R FL have improved with T-cell–redirecting treatments (e.g. CAR T-cell therapy, bispecific antibodies), there remains an unmet need for safe, efficacious, and more convenient chemotherapy-free treatment options (Caridà et al, Eur J Haematol. 2025). 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 FL (Cordoba et al, ICML 2025, #441). Here, we provide longer follow-up in patients with R/R FL from Part B of the study. Methods Patients with R/R FL with ≥ 2 prior lines of therapy (≥ 1 in Part B if prior anti-CD20 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 72 patients with R/R FL were enrolled: 12 in Part A (GOLCA monotherapy) and 60 in Part B Cohort D (22 received GOLCA 0.2 mg + R; 38 received GOLCA 0.4 mg + R). Patients were heavily pre-treated. Median number of prior treatments was 4.5 (range, 2–6) in Part A and 3 (range, 1–12) in Part B Cohort D. Approximately one-third of the treated patients were exposed to prior T-cell–redirecting therapy, approximately one-third had prior lenalidomide (len) exposure, and approximately one-third were refractory to the last regimen received. At the time of data cutoff, in Part A, 4 patients completed 2 years of GOLCA, remaining in remission at last follow-up; 8 discontinued due to PD. In Part B Cohort D, 41% of patients treated with 0.2 mg and 63% with 0.4 mg were ongoing. PD was the most common reason for discontinuation. In the safety evaluable population (n = 60; GOLCA 0.2 or 0.4 mg + R), neutropenia, an on-target side effect of GOLCA, was the most common grade 3/4 treatment-emergent adverse event (TEAE) and occurred in 65% of patients, followed by anemia (13%) and febrile neutropenia (8%). Serious AEs related to GOLCA occurred in 22% of patients, most commonly infections (17%) and febrile neutropenia (7%); pulmonary embolism occurred in 1 patient with 0.2 mg. The most common causes of GOLCA interruption in the overall safety population were infections (32%) and neutropenia (18%). Dose reductions were mostly due to neutropenia (10%) and febrile neutropenia (5%). No discontinuations or deaths occurred from GOLCA-related TEAEs. Non-hematologic TEAEs were infrequent and mostly low grade, with the most common being gastrointestinal disorders (7%). In the efficacy evaluable patients (n = 56; GOLCA 0.2 or 0.4 mg + R) at a median follow-up of 10.8 months, the overall response rate (ORR) was 89% (complete response rate [CRR], 61%). With 0.2 mg, ORR was 81% (CRR, 43%) and with 0.4 mg, ORR was 94% (CRR, 71%). In the 0.4-mg group, responses were consistent in high-risk subsets, including patients with prior len (ORR, 100%; CRR, 73%) and/or T-cell–redirecting therapy (ORR, 91%; CRR, 64%). With GOLCA 0.4 mg, 10 patients had response lasting > 12 months, including 5 with prior T-cell–redirecting therapy and 6 with prior len. Conclusions With additional follow-up, GOLCA + R continued to show promising efficacy with durable responses and no new safety signals. A higher ORR/CRR and similar tolerability were observed with GOLCA 0.4 mg + R vs GOLCA 0.2 mg + R, including in patients with prior len-based and/or T-cell–redirecting treatment. These data support continued development of GOLCA 0.4 mg + R as a fixed-duration, chemotherapy-free, outpatient option in the ongoing Phase 3 GOLSEEK-4 study in 2L+ FL (NCT06911502).

Introduction: GOLCA is a potential first-in-class CELMoDTM agent for the treatment of lymphoma, purposefully designed to target the proteins Ikaros/Aiolos to produce dual immunomodulatory and anti-tumor activity, with preferential distribution to lymphoid organs. Pharmacodynamic data in pts with R/R FL show that, combined with RTX, the immunomodulatory effects of GOLCA are significantly increased (Chavez et al, EHA 2024, #1132). GOLCA as monotherapy (mono) and + RTX has been shown to be well-tolerated and effective in pts with R/R DLBCL (Chavez et al, ASH 2023, #4496) and R/R FL (Chavez et al, EHA 2024, #1132). Here, we report 30 mo follow up of pts with R/R FL who received GOLCA mono, and updated safety/efficacy of GOLCA + RTX from the ongoing Phase 1/2 CC-99282-NHL-001 study (NCT03930953). Methods: Pts with R/R FL with ≥ 2 prior lines of therapy (L) received GOLCA mono at different dosing schedules during part A (dose exploration) and GOLCA ± RTX at 0.2 mg or 0.4 mg days (d) 1-14 every 28 d (q28d) in part B (dose expansion). Total treatment duration with GOLCA was up to 2 years or until progressive disease or unacceptable toxicity, whichever occurred first. The efficacy-evaluable population consisted of pts completing ≥ 1 cycle of GOLCA and having baseline tumor assessment and ≥ 1 post-baseline tumor assessment or clinical progression or disease-related death. Results: As of May 31, 2024, 63 pts with R/R FL have enrolled: GOLCA mono (n = 19) at various dosing schedules and GOLCA + RTX at 0.2 mg (n = 22) or 0.4 mg (n = 22) on d1-14 q28d schedule. The median time from diagnosis to first dose of GOLCA was 68 mo (range, 23-136) and 59 mo (range, 15-309) in GOLCA mono and + RTX cohorts, respectively. The median number of prior therapies received was 4 (range, 2-11), and 3 (range, 1-12) in GOLCA mono and + RTX cohorts, respectively. In the GOLCA mono and + RTX cohorts, 9/19 (47%) and 13/43 (30%) pts had received prior lenalidomide (len)-based therapy, with 5/9 and 7/13 having len-refractory disease, respectively. In the GOLCA + RTX cohort, 10/43 (23%) had prior CAR T cell therapy and 6/43 (14%) had prior anti-CD20xCD3 bispecific antibody with or without CAR T cell therapy. In the GOLCA + RTX-treated safety population (n = 43), the incidence of treatment emergent adverse events (TEAEs) was similar across 0.2 and 0.4 mg dose levels (DL). The most frequent grade (G) 3+ TEAEs were neutropenia (44%) and anemia (12%). The incidence of febrile neutropenia was 7%. Serious adverse events occurred in 30% of pts, with febrile neutropenia and pneumonia being the most common, in 2 pts (5%) each, as well as pulmonary embolism in 1 pt. Neutropenia led to GOLCA dose interruption in 4 pts (9%) and dose reduction in 1 pt (2%). No pts discontinued treatment because of GOLCA-related TEAEs. Non-hematological TEAEs (e.g., GI toxicity, rash, fatigue) were all low-grade (except 1 pt with G3 fatigue). There were no new safety signals identified for GOLCA mono (part A) at the 30-mo follow up period. In the efficacy-evaluable population, at a median follow up of 6 mo (range 3-18), the ORR and CRR in the GOLCA + RTX cohort (n = 29) were 57% and 29% at 0.2 mg dose (n = 14) and 93% and 67% at 0.4 mg dose (n = 15), respectively. The median time to response was 2 mo (first response assessment). At the 0.4 mg DL of GOLCA + RTX, consistent responses were seen in pts at 2L/3L and 4L+, including in those with prior exposure to len-based therapies and/or T-cell-redirecting therapy. At the 0.4 mg DL, 12/14 (86%) pts remained in response at the time of data cut-off. In pts receiving GOLCA mono across different dose schedules in part A (n = 12), ORR and CRR were 67% and 42%, respectively. Responses were durable, with median DOR of 22 mo (range, 2-51) at a median follow up of 30 mo. 33% of pts (4/12) have completed 2 yrs of protocol defined GOLCA treatment and remain in response at the 1 yr post-treatment follow-up period, without requiring any intervening treatment. Conclusions: GOLCA 0.4 mg + RTX was well tolerated and highly active in heavily pre-treated pts with R/R FL, including those with prior exposure to len-based therapies and/or T-cell-redirecting therapies. Treatment with fixed-duration GOLCA mono led to durable responses including a subset of pts remaining treatment free, without progression at extended follow up. These data further support development of GOLCA + RTX as a fixed-duration, chemotherapy-free, outpatient treatment option in pts with R/R FL, and also pts with newly diagnosed advanced stage FL (NCT06425302).

Introduction: GOLCA is a potential first-in-class oral cereblon E3 ligase modulator (CELMoD™) agent for non-Hodgkin lymphoma, purposefully designed to target Ikaros/Aiolos and have favorable pharmacokinetics, resulting in apoptotic and immunomodulatory activity with preferential distribution to lymphoid organs. CC-220-DLBCL-001 (NCT04884035) is an ongoing phase 1b, open-label, multicenter, dose-escalation/expansion trial to assess safety and preliminary 1L GOLCA + R-CHOP efficacy in a-BCL. Although longer follow-up is needed to assess durability of response, MRD negativity (MRD-) is an emerging endpoint in a-BCL. Achieving MRD- on and at end of treatment (EOT) can potentially predict clinical benefit. This study aimed to analyze circulating tumor DNA (ctDNA) kinetics of GOLCA + R-CHOP across the trial population and in defined patient (pt) segments-cell of origin (COO), high baseline ctDNA, and high-risk genomics-and to correlate MRD- with imaging and clinical outcomes. Methods: Eligible pts were ≥ 18 years of age with ECOG performance status ≤2, IPI 0-5 in Part 1 and 2-5 in Part 2, and untreated a-BCL with measurable disease. Pts were treated with GOLCA + R-CHOP for 6 x 21-day (D) cycles (C) or until disease progression/unacceptable toxicity/study withdrawal. Dose escalation phase GOLCA dose levels (DLs) were 0.2 mg D1-7 (DL-1), 0.4 mg D1-7 (DL1), or 0.4 mg D1-10 (DL2). During dose expansion, pts were randomized 1:1 to R-CHOP + GOLCA DL-1 or DL1. The primary endpoint was safety of GOLCA at DL1; efficacy was a secondary endpoint, ctDNA was an exploratory endpoint. ctDNA was analyzed using the PhasED-Seq assay (<10-6 sensitivity) at baseline, C2D1, C3D1, and EOT. MRD- was defined as the absence of detectable ctDNA on-treatment. Pretreatment biopsies were sequenced by whole genome sequencing (WGS) and whole transcriptome sequencing (WTS). Results: At data cutoff (June 3, 2024), the median follow-up was 14.3 months. One-year progression-free survival (PFS) was 85.3% at 0.4 mg and 77.3% at 0.2 mg. Rates of MRD- increased over time but were consistently higher at 0.4 vs 0.2 mg, with values of 44% (14/32) vs 29% (8/28) at C2D1; 63% (17/27) vs 54% (15/28) at C3D1, and 90% (26/29) vs 73% (19/26) at EOT, respectively. Interim MRD- at C3D1 strongly predicted EOT MRD-; all 0.4 mg pts and all but two 0.2 mg pts who were MRD- at C3D1 remained MRD- at EOT. In contrast, fold-changes from baseline ctDNA were similar between 0.4 mg and 0.2 mg. The early molecular response rate (≥102-fold drop from baseline at C2D1) was 81.2% (26/32) at 0.4 mg and 82.1% (23/28) at 0.2 mg. The major molecular response rate (≥102.5-fold drop from baseline at C3D1) was 88.9% (24/27) at 0.4 mg and 85.7% (24/28) at 0.2 mg. Across genetically defined pt segments, EOT MRD- at 0.4 mg was prevalent for both COO subtypes measured by the Hans algorithm: 94% (17/18) among germinal center B-cell (GCB) and 75% (6/8) among non-GCB pts. Of the 29 pts with baseline genomics, 13 were genomically high risk: p53 mutant (VAF >0.5), DZsig and/or A7 subtype. In these pts, EOT MRD- was 80% (4/5) at 0.4 mg but only 20% (1/5) at 0.2 mg. In high baseline ctDNA (>102.5 hGE/mL) pts who were high-risk for R-CHOP failure, EOT MRD- at 0.4 mg was 86.7% (13/15) vs 57.1% (8/14) at 0.2 mg. There was an association between high baseline ctDNA and lower PFS at 0.2 mg (HR, 4.56 [95% CI, 0.53-39.12]), but interestingly the association decreased at 0.4 mg (HR, 2.10 [95% CI, 0.19-23.5]). Combining both arms, MRD- at both C3D1 and EOT trends with improved PFS (C3D1: HR, 0.73 [95% CI, 0.2114-2.523]; EOT: HR, 0.53 [95% CI, 0.1103-2.592]); longer follow-up may be required to demonstrate significance. Conclusions: Interim and EOT levels of MRD- were higher at 0.4 mg vs 0.2 mg GOLCA, with a one-year PFS of 85.3% vs 77.3%, respectively. Although pt numbers were small, the data suggest that 0.4 mg is efficacious in high-risk ctDNA and high-genomic risk pts, independent of COO, and support the 0.4 mg GOLCA + R-CHOP regimen in the randomized phase 3 trial GOLSEEK-1. Interim MRD- may play a role in future adaptive trial designs.

Background and Significance When patients (pts) with follicular lymphoma (FL) present with a high tumor burden, they require systemic treatment with rituximab (R) in combination with chemotherapy (chemo). Given the known cumulative toxicities of chemotherapy and the older age of pts at the time of diagnosis, novel chemo-free treatment approaches are desired by pts as well as physicians. R-lenalidomide (R-Len), a chemo-free alternative to R-based chemoimmunotherapy, has recently been listed as a chemo-free option in the National Comprehensive Cancer Network® (NCCN) guidelines. Golcadomide (GOLCA) is a potential first-in-class oral cereblon E3 ligase modulator (CELMoD™) agent purposefully designed for the treatment of lymphoma. GOLCA co-opts cereblon to induce targeted degradation of the transcription factors Ikaros/Aiolos, inducing deep, rapid, and extensive tumor killing, independent of cell of origin, and enhanced immunostimulatory activity. Compared with immunomodulatory (IMiD) agents like lenalidomide, GOLCA more efficiently drives the cereblon complex to the closed active state resulting in more potent degradation (Watson ER et al, Science 2022), which is expected to translate into improved clinical benefit. In addition, the phase 1/2 study CC-99282-NHL-001 showed that GOLCA alone or in combination with R (GOLCA-R) was well tolerated and showed promising activity in pts with heavily pre-treated relapsed/refractory (R/R) FL, including in those with prior Len-based therapies and/or T cell-redirecting therapies (Chavez et al, EHA 2024). Based on this, GOLSEEK-2 (NCT06425302) is a randomized phase 2 trial assessing the efficacy and safety of GOLCA-R as a chemo-free option in pts with newly diagnosed advanced-stage FL. Study Design and Methods After a screening period of ≤ 5 weeks, approximately 90 pts with newly diagnosed advanced-stage FL will be randomized 1:1:1 between GOLCA plus rituximab at a dose of 0.2 mg or 0.4 mg once daily from day 1 to 14 every 28 days for 12 cycles or investigator's choice R-chemo (R-CHOP or R-bendamustine). R maintenance could be considered (as per pt and physician decision) for pts who achieve a partial response or better after completion of initial therapy for up to one year in GOLCA-R arms and up to one and a half years in the R-chemo arm. Pts with histologically confirmed diagnosis of grade 1, 2, 3a FL, or classic FL according to WHO classification would be eligible for the study. Other key inclusion criteria include no prior systemic treatment for FL, stage II-IV disease, the requirement for treatment as per investigator's judgment, and measurable disease as defined by Lugano 2014 criteria. Key exclusion criteria include other lymphoma subtypes, clinical evidence of transformed lymphoma, and documented or suspected central nervous system involvement. The primary endpoint is complete metabolic response (CMR) during the GOLCA plus rituximab combination treatment period, assessed by the investigator and based on Lugano 2014 Response Criteria. Secondary endpoints include progression-free survival, overall survival, overall response rate, duration of response, complete response rate at 30 months, CMR rate at 6 months and 12 months, and safety outcomes.

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), typically administered for 6 cycles, is the standard therapy for DLBCL and is curative in ~60-70% of patients (pts). However, 30-40% of pts have relapsed/refractory (RR) DLBCL following treatment with R-CHOP, with poor clinical outcomes. International Prognostic Index (IPI) scores of 3-5 are used to identify high-risk (HR) pts who are more likely to be RR following treatment. Additionally, pts with IPI scores of 1-2 who also have bulky disease and/or very high lactate dehydrogenase levels (LDH), have been identified as a HR subset with similar outcomes to pts with an IPI score of 3 (Maurer et al. ASH 2023, #4512). First-line therapy represents the greatest opportunity to address the unmet need for these pts. Golcadomide (GOLCA) is a potential first-in-class oral cereblon E3 ligase modulator (CELMoD™) agent purposefully designed for the treatment of lymphoma. GOLCA co-opts cereblon to induce targeted degradation of the transcription factors Ikaros/Aiolos, inducing deep, rapid, and extensive tumor killing, independent of cell of origin, and enhanced immunostimulatory activity. In the phase 1b study CC-220-DLBCL-001, GOLCA combined with R-CHOP was well tolerated, showing promising activity and combinability with high rates of durable responses irrespective of cell of origin in pts with previously untreated aggressive BCL, including those with HR disease (Hoffmann et al. EHA 2024, S235). Additionally, GOLCA has shown encouraging efficacy and safety profiles in pts with RR DLBCL, both as a monotherapy (Michot et al. ICML 2023, P90) and in combination with rituximab (Chavez et al. ASH 2023, P4496). The efficacy and safety data observed in early-phase studies suggest promising activity and a manageable safety profile. This supports further investigation of the GOLCA + R-CHOP combination in the phase 3 setting. Here, we present the study design of GOLSEEK-1, a multicenter, randomized, double-blind, placebo-controlled phase 3 study (NCT06356129) comparing the efficacy and safety of GOLCA + R-CHOP vs placebo + R-CHOP in pts with previously untreated HR LBCL. Study Design and Methods Approximately 850 pts with previously untreated LBCL will be randomized 1:1 to either GOLCA + R-CHOP or placebo + R-CHOP. Pts must have a histologically confirmed diagnosis of LBCL according to WHO 2022 classification, including: DLBCL, not otherwise specified (NOS) including ABC and GCB subtypes; high-grade B-cell lymphoma with MYC and BCL2 rearrangements, or NOS; T-cell/histiocyte-rich LBCL; Epstein-Barr Virus-Positive DLBCL. Other key inclusion criteria include an IPI score of 1 or 2 considered HR (LDH > 1.3 × upper limit of normal and/or bulky disease, defined as a single lesion of ≥ 7 cm [Maurer et al. ASH 2023, #4512]), or IPI score ≥ 3; and measurable disease as defined by the Lugano classification. Key exclusion criteria include 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, as well as documented or suspected central nervous system involvement. Randomization will be stratified by IPI score (1-2 with risk factors and 3 vs 4-5) and bulky disease (> 7 cm vs ≤ 7 cm). After a screening period of ≤ 4 weeks, pts will receive GOLCA (0.4 mg) or placebo orally once daily for 7 consecutive days in each of 6 cycles in combination with R-CHOP in 21-day cycles. The primary endpoint of this study is progression-free survival (PFS) in untreated HR LBCL, assessed by investigator based on the Lugano Response Criteria. Key secondary endpoints include PFS in untreated non-high-grade BCL, event-free survival in pts with untreated HR LBCL, independently assessed complete metabolic response rate, undetectable minimal residual disease by PhasED-Seq (defined as undetectable circulating tumor DNA levels at treatment end), and overall survival. Patient follow-up will occur for up to approximately 67 months after beginning treatment. This study is recruiting at 293 sites in 37 countries, across the United States, Europe, Latin America, and East Asia.

Introduction Golcadomide (GOLCA, CC-99282) is an orally available cereblon E3 ligase modulator (CELMoD ®) that potently degrades target proteins Ikaros and Aiolos, enhancing antiproliferative, apoptotic, and immunomodulatory activity and preferentially distributing to lymphoid organs. In a phase 1 study, GOLCA monotherapy previously demonstrated a manageable safety profile with promising clinical activity in relapsed/refractory non-Hodgkin lymphoma (Michot Blood 2021). In the ongoing CC-220-DLBCL-001 study (NCT04884035), GOLCA dose finding is underway in patients with previously untreated aggressive B-cell lymphoma (BCL), in combination with R-CHOP in 21-day (D) cycles (C), at a variety of GOLCA dose levels (DLs) and schedules: DL-1 = 0.2 mg D1-7, DL1 = 0.4 mg D1-7, and DL2 = 0.4 mg D1-10. Here, we report Ikaros degradation, immune modulation, circulating tumor DNA (ctDNA) assessment, and baseline tumor genomics. Methods Peripheral blood was collected to analyze Ikaros and Aiolos levels in T cells by flow cytometry (C1D1, C1D7, and C2D1). Immune phenotyping of T and natural killer (NK) cells was performed by flow cytometry (C1D1, C1D15, C2D1, and C3D1). ctDNA levels were analyzed by the PhasED-Seq assay (timepoints C1D1, C2D1, C3D1, and end of treatment [EOT]; Kurtz Nat Biotechnol 2021); somatic variants were filtered by performing PhasED-seq on buffy coats. Pretreatment biopsies were analyzed by whole genome sequencing and whole transcriptome sequencing. DL1 (0.4 mg D1-7) and DL2 (0.4 mg D1-10) data were pooled. Results Ikaros levels in T cells at 5 hours after the first dose had a 1.1% median increase with 0.2 mg and 44% median decrease with 0.4 mg; by C1D7 pretreatment, Ikaros substantially decreased with both DLs (median: 0.2 mg, 87% decrease; 0.4 mg, 83% decrease). Ikaros differences between 0.2 mg and 0.4 mg were not substantial. By C2D1, Ikaros levels recovered to baseline. Based on preclinical benchmarks, steady-state Ikaros degradation in T cells suggested that direct tumor cell killing by GOLCA was achieved. Changes in T and NK cell phenotypes in peripheral blood included activation, increased proliferation, increased T effector memory and regulatory cell levels, and decrease in naive T cells. Changes were seen by C1D15 and maintained at C2D1 and C3D1. Overall, immune changes between 0.2 mg and 0.4 mg dose levels were not substantially different. Phased variant data from ctDNA and buffy coats were evaluable for 34 patients (0.2 mg, n =15; 0.4 mg, n = 19). Baseline ctDNA levels were similar between the 0.2 mg and 0.4 mg cohorts and, consistent with prior studies, correlated with International Prognostic Index and cell of origin. Previously reported landmarks such as early molecular response (EMR; ≥ 2 log decrease) at C2D1 and major molecular response (MMR; ≥ 2.5 log decrease) at C3D1 were assessed (Kurtz J Clin Oncol 2018) . A high fraction of patients designated high risk by pretreatment ctDNA (≥ 2.5 log haploid genome equivalents [HGE]/mL; Kurtz J Clin Oncol 2018) were clinical responders. Patients who achieved minimal residual disease (MRD) negativity on treatment generally remained MRD negative at subsequent timepoints. At C2D1, the EMR and MRD negativity rates for 0.2 mg were 73% (11/15) and 20% (3/15), respectively; for 0.4 mg these rates were 83% (15/18) and 44% (8/18). At C3D1, the MMR and MRD negativity rates for 0.2 mg were 83% (10/12) and 42% (5/12), respectively; for 0.4 mg these were 83% (10/12) and 58% (7/12). Although ctDNA differences between 0.2 mg and 0.4 mg were not substantial, numerically greater ctDNA changes were seen with 0.4 mg GOLCA + R-CHOP vs 0.2 mg GOLCA + R-CHOP and vs R-CHOP and R-CHOP-like regimens from other cohorts ( Figure). Insufficient samples were available to draw conclusions about EOT, but additional ctDNA data will be presented. Whole genome and transcriptome sequencing data from GOLCA + R-CHOP-treated patients will be shown. Conclusions Pharmacodynamic biomarkers and ctDNA levels indicate that both tumor-intrinsic and immune-modulating mechanisms of action of GOLCA remain relevant in combination with R-CHOP in previously untreated aggressive BCL. ctDNA data during treatment are consistent with the efficacy noted on clinical restaging. Translational data demonstrate the potency of GOLCA and will support future frontline clinical trial designs in patients with untreated aggressive BCL. Study support: Celgene, a Bristol-Myers Squibb Company