Boccia, Ralph V.

e13124 Background: Bria-IMT, an allogeneic whole-cell cancer vaccine (SV-BR-1-GM), was administered w/ an anti PD1 checkpoint inhibitor (CPI) to evaluate its safety and efficacy in advanced/metastatic breast cancer (MBC). SV-BR-1-GM breast cancer cells were engineered to directly stimulate anti-tumor immunity through expression of tumor associated antigens and secretion of GM-CSF to enhance endogenous dendritic cell activation. Addition of a CPI potentiates SV-BR-1-GM action by overcoming the immune suppressive tumor microenvironment and may have a differential impact vs monotherapy SV-BR-1-GM. Methods: In this exploratory analysis of the Phase 1 + randomized Phase 2, HLA matching status was assessed to explore potential correlations w/ clinical outcomes. Pts were stratified by overall HLA match by Class I or II (0 vs ≥1 matches), formulation and MBC subtype to assess objective response rate (ORR), clinical benefit rate (CBR), progression free survival (PFS), and overall survival (OS). Partial HLA matching (≥1 Class I and ≥1 Class II allele) was also analyzed. Results: In the total pt population, the ORR was 10%, CBR 56%, PFS 3.2 months and OS 9.9 months. In those pts treated w/ the phase 3 formulation, ORR was 15%, CBR 63%, PFS 3.6 months and OS 13.4 months. Using available HLA data (n = 52), 25% had 0, 34.6% 1, 32.6% 2, and 8% ≥3 matches. While OS and PFS were greater (Undefined vs 8.5 mos ; p = .02) in pts without an HLA match compared w/ those w/ ≥1 match (see Table), ORR and CBR were similar. This was also the case for pts who had 0 HLA Class I matches vs those w/ ≥1 Class I match (15.6 vs 7.2 mos; p = .002). ORR, CBR, PFS and OS were generally similar for pts who had 0 Class II HLA matches vs those w/ ≥1 match. Pts who matched at least at 1 Class I and 1 Class II allele had a higher ORR and CBR than those who matched at a single Class I or a single Class II allele although PFS and OS were similar between the groups. Similar observations were seen for pts treated w/ the phase 3 formulation. Conclusions: Matching at Class I seemed to decrease PFS & OS, but did not have a similar effect on ORR and CBR. Both matched and non matched pts demonstrated favorable OS and response rates. These findings support further investigation into specific mechanisms and the clinical significance of HLA matching in immunotherapy response. A randomized phase 3 trial is ongoing comparing Bria-IMT vs treatment of physician's choice (NCT06072612). Clinical trial information: NCT03328026 . n (Evaluable) % of Cohort Best ORR Best CBR PFS OS Full Cohort 52 (41) 10% 56% 3.2 9.9 No Match (Overall) 13 (10) 25% 20% 60% 4.2 Undefined Any Match (Overall) 39 (31) 75% 6% 55% 3 8.5 MHC Class I No Match / Any Match 27 (20) / 25 (21) 52% / 48% 10% /10% 55% /57% 3.5 / 2.7 15.6 / 7.23 MHC Class II Any Match 27 (19) 52% 11% 63% 3.2 11.4 MHC Class I&II Match 13 (9) 25% 22% 77% 2.8 8.6 Phase 3 Formulation (N=35) 35 (27) 15% 63% 3.57 13.43 No Match (Phase 3 Formulation) 11 (9) 31% 22% 67% 5.6 Undefined MHC Class I&II Match (Phase 3 Formulation) 11 (7) 31% 29% 71% 2.7 7.23

1096 Background: Bria-IMT is a combination immunotherapy consisting of allogeneic whole cell cancer vaccine (SV-BR-1-GM) administered w/ immune checkpoint inhibitor (CPI). SV-BR-1-GM breast cancer cells are engineered to directly stimulate anti tumor immunity via expression of tumor associated antigens and secretion of GM-CSF to enhance dendritic cell activation. Addition of CPI potentiates SV-BR-1-GM to overcome the immune suppressive tumor microenvironment. Methods: This Ph I/randomized Ph II study evaluated the Bria-IMT regimen in pts w/ metastatic breast cancer; CTX (300 mg/m²) on day -2/-3, SV-BR-1-GM and CPI on Day 0, w/ low dose peg interferon α at inoculation sites on day 2 (±1) . Phase II pts were randomized 1:1 to receive CPI at cycle 1 or cycle 2. Two SV-BR-1-GM formulations (w/ vs w/o IFNγ incubation) were evaluated. Biomarkers included cancer-associated macrophage-like cells, circulating tumor cells, PD-L1 scores, and delayed-type hypersensitivity skin tests. Results: 54 pts (22 Ph I, 32 Ph II) enrolled; 11 received pembrolizumab, 44 retifanlimab (1 crossover). 33 (61%) pts were ER+/PR+/HER2-, 18 (33%) TNBC, 3 (6%) HER2+. Median OS, PFS, ORR, and CBR were evaluated against two pivotal Ph 3 trials, ASCENT 1 (SG in TNBC) and TROPiCS-02 2 (SG in HR+/HER2- MBC) (see Table 1). In randomized pts, C1 vs C2 CPI had PFS (3.7 vs 3.2 mos, P=0.09) and OS (11.4 vs 7.4 mos, P=0.19). Pts receiving Ph 3 formulation (w/o IFNγ; N=37) had greater PFS (3.6 vs 2.6 mos, P=0.01) and OS (13.4 vs 6.9 mos, P=0.01). Bria-IMT was well tolerated w/ no Tx related D/Cs. Conclusions: The Bria-IMT Ph 3 formulation cohort OS was comparable to ASCENT and TROPiCS-02 (13.43 vs 11.8, 14.4 mos), exceeding TPC arms (6.9, 11.2 mos). CBR (61%) compared favorably to ASCENT (40%) and TROPiCS-02 (34%); ORR (14%) matched or exceeded TPC arms (4%, 14%). These outcomes were observed in a more heavily pretreated population, demonstrating Bria-IMT’s clinical activity. Randomized Ph 2 results suggest efficacy and safety in heavily pretreated MBC, w/ no significant OS difference between C1 and C2 CPI initiation and 22% of pts still in active survival follow up. Superior outcomes w/ the Ph 3 formulation support its continued evaluation. A randomized Ph 3 trial is ongoing, comparing Bria-IMT vs treatment of physician’s choice (NCT06072612). Clinical trial information: NCT03328026 . Trial (Cohort) Age (Median, Range) Prior Therapies (Median) OS (Median, mos) PFS (Median, mos) ORR (%) CBR (%) Bria-IMT (Overall Cohort) 61 (38-81) 6 (2-13) 9.9 (1.8-30.3) 3.6 10% 55% Bria-IMT (Ph 3 Formulation) 62 (44-80) 6 (2-13) 13.43 (1.8-30.3) 3.6 (1.8-16.5) 14% 61% ASCENT (SG) 54 (27-82) 4 (2-17) 11.8 4.8 31% 40% ASCENT (TPC) 53 (27-81) 4 (2-14) 6.9 1.7 4% 8% TROPiCS-02 (SG) 57 (49-65) 3 14.4 5.5 21% 34% TROPiCS-02 (TPC) 55 (48-63) 3 11.2 4 14% 22% References: Bardia A et al. J Clin Oncol. 2024 May 20;42(15):1738-1744Rugo, Hope S et al. The Lancet, Volume 402, Issue 10411, 1423 – 1433.

Abstract Background: Bria-IMT™ is a combination immunotherapy consisting of allogeneic whole-cell cancer vaccine (SV-BR-1-GM) administered w/ immune checkpoint inhibitor (CPI). SV-BR-1-GM breast cancer cells have been engineered to directly stimulate anti-tumor immunity through expression of tumor-associated antigens and secretion of GM-CSF to enhance dendritic cell activation. Addition of CPI potentiates SV-BR-1-GM to overcome the immune-suppressive tumor microenvironment. Methods: This Phase I and randomized phase II combination study evaluated the Bria-IMT™ regimen: preconditioning w/ CTX (300 mg/m2) on day -2 or -3, SV-BR-1-GM inoculation and CPI administration on Day 0, and low-dose peg- interferon α at inoculation sites 2 (±1) day post-SV-BR-1-GM. Phase II pts were randomized 1:1 to receive CPI at cycle 1 (immediate) or cycle 2 (delayed). Two SV-BR-1-GM formulations (w/ and w/o IFNγ incubation) were evaluated. Biomarkers included cancer-associated macrophage-like cells (CAMLs), circulating tumor cells (CTCs), PD-L1 scores, and delayed-type hypersensitivity (DTH) skin tests. Results: 54 pts (22 in Phase I, 32 in Phase II) enrolled. 11 pts received pembrolizumab, 44 retifanlimab, w/ 1 pt transitioning from pembrolizumab to retifanlimab. Median age 61(38-81) years; median 6(2-13) prior regimens. 33(61%) pts were ER+/PR+/HER2-, 18(33%) TNBC, and 3(6%) HER2+. Bria-IMT regimen was well tolerated, w/ no attributable Tx D/C. 67% of adverse events grade 1-2; 13% ≥ grade 3 including pulmonary embolism, increased lipase, and dehydration. Median overall survival (OS) was 9.9 (1.8 - 30.3) mos w/ 13% of pts in active survival follow-up. Median progression free survival (PFS) was 3.2 (1.1-16.5) mos w/ 1 pt still in treatment (16.5 mos). Pts treated w/ ph 3 formulation (w/o IFNγ; N = 37) had significantly improved PFS (3.6 vs. 2.6 mos, P=0.01) and OS (13.4 vs. 6.9 mos, P=0.01); in evaluable pts, objective response rate was 14% and clinical benefit rate 61%. Randomized pts receiving ph 3 formulation had not reached median OS. In randomized pts, C1 vs C2 CPI initiation showed greater PFS (3.7 vs. 3.2 mos, P=0.09) and OS (11.4 vs. 7.4 mos, P=0.19). OS in pts w/ no HLA match was undefined vs 8.6 mos in pts w/ any match (P = 0.04). DTH (+) vs (-) correlated w/ greater OS (11.9 vs. 4.7 mos, P= <0.0001) and PFS (3.5 vs. 2.4 mos, P=0.001). Conclusion: Randomized phase 2 Bria-IMT demonstrated efficacy and safety in heavily pretreated MBC. Post-progression survival exceeding median OS in pts still undergoing survival follow-up suggests long-term benefit extending beyond treatment period. C1 vs C2 CPI initiation showed no statistical or clinically significant difference in OS. Superior outcomes w/ phase 3 formulation support its use in future trials. These results confirm earlier reports of the trial and an even greater benefit. A randomized phase 3 trial is ongoing comparing Bria-IMT vs treatment of physician's choice (NCT06072612). Trial Information: NCT03328026 Citation Format: Saranya Chumsri, Chaitali Nangia, Minal Barve, Kendrith Rowland, Ralph Boccia, John Knecht, Blaise Bayer, Marcela Salgado, Tamar Aghajanian, William V. Williams, Charles Wiseman, Giuseppe Del Priore, Carmen Calfa. Survival outcomes in a randomized phase 2 ofBria-IMT: An allogeneic whole cell cancer vaccine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_2):Abstract nr CT100.

Introduction: Waldenström macroglobulinemia (WM)remains incurable with current therapies. Treatment options for patients beyond initial therapy are limited, underscoring the need for new agents with novel mechanisms of action. Iopofosine I 131 is a novel radiopharmaceutical composed of a lipid raft-targeting phospholipid ether covalently bound to 131I, a beta-emitting radioisotope. Herein, we report the results of the CLOVER-WaM study [NCT02952508] in patients with previously treated WM. Methods: Eligible WM patients had received >2 prior therapies and had symptomatic disease requiring therapy according to consensus recommendations for WM. Treatment consisted of 2 cycles of iopofosine I 131 administered at 15 mCi/m2 on days 1 and 15 of each 57-day cycle. Dose reduction to 10 mCi/m2 was allowed in the second cycle in patients with incomplete hematologic recovery or if the expected total dose exceeded 132 mCi. Supportive care with growth factors and transfusions was permitted per treating physician discretion. The primary endpoint was major response rate (MRR, defined as partial response or better) as determined by the modified VIth International Workshop on Waldenström Macroglobulinemia Response Criteria. Secondary endpoints included overall response rate (ORR), treatment-free survival (TFS), duration of response (DOR), and clinical benefit rate (CBR, defined as stable disease or better). Efficacy endpoints were assessed in the modified intent-to-treat (mITT) population, defined as all patients who received ≥60 mCi total administered dose of iopofosine I 131. MRR was analyzed with a 95% 2-sided confidence interval (CI) using the Clopper-Pearson interval method. In this population, MRR >20% was considered statistically significant. Time-dependent efficacy endpoints were analyzed using the Kaplan-Meier method. Safety was evaluated using CTCAE v4.03 in patients who received >1 dose of iopofosine I 131. The data cut-off for this analysis was May 31, 2024. Results: In 65 patients enrolled (safety population), the median age was 70 (range, 50-88) years; 48 (73.8%) were male, and 17 (26.2%) were female. Sixty-one (93.8%) were White, 1 (1.5%) was Black/African American, and 3 (4.6%) were other or unknown. Fifty-five patients met mITT criteria and were evaluable for efficacy. The median number of prior therapies was 4 (range, 2-15). Bruton's tyrosine kinase inhibitor (BTKi) exposure was noted in 39 (71%) patients, of whom 31 (56%) were BTKi-refractory. Sixteen (29%) patients had MYD88-wild type, and 5 (9%) had CXCR4-mutated disease. The MRR was 56.4% (95% CI, 42.3-69.7). ORR was 80%; among MYD88-wild type patients, ORR was 81%, and among post-BTKi patients, ORR was 72%. CBR was 98%. The median DOR and TFS were not reached at a median follow-up of 8.8 months, with an estimated 72% of responding patients remaining progression-free at 18 months. In the safety population, any-grade adverse events, regardless of causality, were reported in 57 (87%) patients. Grade 3 or higher treatment-emergent adverse events (TEAEs) occurring in >10% of patients included thrombocytopenia (80%), neutropenia (69.2%), anemia (44.6%), lymphopenia (13.8%), infections (12.3%), and febrile neutropenia (10.8%). Adverse event-related death occurred in 1 patient due to bacterial sepsis. Conclusion: Iopofosine I 131 demonstrated durable efficacy in previously treated WM patients, with no current standard of care therapy. The treatment was well-tolerated with a manageable toxicity profile across broad biologic and clinical subgroups, irrespective of risk stratification. Based on the results of this trial, iopofosine I 131 shows promise as a novel treatment for WM patients.

1022 Background: The Bria-IMT regimen is a combination immunotherapy using an allogeneic whole cell cancer vaccine combined with checkpoint inhibitors (CPIs). Intradermally administered irradiated SV-BR-1-GM breast cancer cells secrete GM-CSF and present tumor associated antigens (TAAs) on HLA-I and –II molecules to directly stimulate anti-tumor immunity. Anti-PD1 CPI further stimulates T-cells and synergizes with SV-BR-1-GM. Here we report the results of the phase 1/2 trial (NCT03328026) of Bria-IMT in metastatic/advanced breast cancer evaluating sequencing of SV-BR-1-GM inoculation and CPI. Methods: Analysis of the phase 1 with expansion phase 2 cohort randomized by sequence using SV-BR-1-GM, checkpoint inhibitor (pembrolizumab or retifanlimab), low dose cyclophosphamide (Day –2) and post-dose local pegylated interferon α, with cycles every 3 weeks. In the 1:1 randomized cohort, CPI is either dosed at C1 prior to SV-BR-1-GM (original sequence) or delayed to C2 post-SV-BR-1-GM (alternative sequence). Cancer-associated macrophage-like cells (CAMLs) and circulating tumor cells (CTCs) were monitored as biomarkers. Results: A total of 54 patients were dosed: 11 with pembrolizumab, 44 with retifanlimab (1 patient received pembrolizumab and later retifanlimab). Median age=61 (38-81); Median prior regimen=6 (2-13); 72% ER+/PR+/HER2-; 6% HER2+ and 22% triple negative. Bria-IMT regimen was well tolerated with only 9% drop-out rate due to AE. AEs related to IPs were seen in 74% of patients; the majority (91%) being grade 1-2, and few (1.7%) grade 4 cases including pulmonary embolism, dehydration and increased lipase. Among 30 patients with post-dose CAML/CTC data and evaluable outcome, CAML count <5 associates with disease control (p=0.06, Chi square test). Patients who developed DTH to SV-BR-1-GM had significantly better PFS and higher OS. Patients treated with phase III formulation had an increase in PFS. Quality of life improvement correlates with disease outcome and survival. Among the patients treated with the phase III formulation of SV-BR-1-GM (n=23 with evaluable outcomes), objective response rate (ORR) is 13% and disease control rate (DCR) is 61%, with median PFS and OS are 4.1 and 13.3 months, respectively. In the randomized portion, the original sequence cohort had higher DCR (43% vs 36%) and OS (P=0.08, HR 0.30, 95%CI 0.08-1.17) compared to the alternative sequence cohort. Conclusions: BRIA-IMT has shown a favorable safety profile while providing benefits to heavily treated aMBC patients. Superior outcomes and survival were seen in patients treated with the phase III formulation and regimen now being used in the ongoing Ph3 trial, confirming the improvement in efficacy of the novel regimen. The results from this randomized phase 2 study informed the study design of the ongoing Ph3 trial comparing BRIA-IMT to standard of care physician choice treatments (NCT06072612). Clinical trial information: NCT03328026 .

Abstract Introduction Despite progress in MBC, too many continue to succumb due to treatment resistance or intolerance. SV-BR-1-GM is an allogenic human breast cancer cell line with antigen presenting cell activity designed to overcome the immune-suppressive tumor microenvironment while being acceptable to extensively pretreated contemporary MBC patients. We report interim exploratory analysis of the ongoing RCT of the Bria-IMT regimens. Methods An interim exploratory analysis using preliminary partially available evaluable data of the ongoing prospective, randomized phase 2 (NCT03328026; 2018-present) of Bria-IMT (irradiated SV-BR-1-GM) with a PD-1check point inhibitor (CPI) every 3 weeks (25 patients dosed to date). Both regimens include cyclophosphamide 300 mg/m2 48-72 hours prior to intradermal Bria-IMT (~20 x 106 cells) followed by interferon-alpha at the inoculation sites 2 days later. The control arm used the original sequence with simultaneous start of Bria-IMT and CPI in cycle 1. The experimental arm started CPI in cycle 2 after the 2nd inoculation. Candida skin test was performed before cycle 1 to determine anergy status while delayed-type hypersensitivity skin test (DTH), defined as &gt;5mm erythema & induration, was done at every cycle by intradermal injection of a small test dose of Bria-IMT prior to full dose inoculation. Results Median age: 58 (range 37-81); median prior therapies: 8 lines (range 4-18); 89% were grade 2/3 (n=18); 68% hormone receptor positive; 61% HER2 negative, 33% HER2 low, and 6% HER2 high; 33% triple negative. Overall, 53% of subjects had a clinical benefit as best response by BICR, PI or target lesion measurement. The two treatment arms were similar with a trend showing longer median durations on therapy (mDOT) of 3.7 mo in the experimental delayed CPI arm compared with mDOT = 2.9 for original sequence control arm. 47% of patients were anergic to candida. Among all anergic subjects, the mDOT was 3.5 compared to 2.5 mo for non-anergic patients. However, among anergic subjects, the alternative treatment arm had a lower risk of treatment discontinuation (improved HR) with mDOT of 3.7 compared to the 3.3 mo mDOT of the original treatment. 50% of anergic subjects eventually developed DTH to SV-BR-1-GM. mDOT was 4.0 mo for DTH+ pts vs 3.0 mo for those who did not mount DTH. Median OS was not yet reached; mean OS was higher in non-anergic vs anergic pts. Among those who developed an inoculation site reaction to Bria-IMT, OS was greater than for those who did not. Time on the Bria-IMT regimen exceeded the time on penultimate treatment in 22% of subjects while 33% of subjects with prior CPI use exceeded last therapy. AEs were mild with 28% of subjects (n=7) having &gt; grade 3 events. The most common grade 3+ AE was lipase increase (n=3). One subject with encouraging changes in peripheral blood tumor markers and CTCs completed a PET study using Zr-89 crefmirlimab berdoxam, a zirconium-89 labelled truncated antibody specific to human CD8α (CD8 Immuno-PET) and demonstrated increased uptake in some metastatic lesions and draining lymph nodes. Updated results will be provided at the meeting. Conclusion Sequencing of CPI with Bria-IMT is associated with differential clinical outcome trends but not statistically significant in this interim preliminary exploratory analysis regardless of prior CPI use. Bria-IMT is immunogenic with clinical benefit demonstrated for both treatment schedules among patients with inducible DTH reactions. Patients who develop an immune response to Bria-IMT had an increase in OS compared to those who did not. The nodal localization of CD8+ cells on PET may indicate a systemic activation of CD8 positive lymphoid cells. It also provides support that the Bria-IMT + CPI combination immune-based therapy can result in an increase of CD8+ tumor infiltrating lymphocytes in breast cancer metastatic sites. These preliminary results will be evaluated in the ongoing randomized phase 3 pivotal registrational trial. Citation Format: Carmen Calfa, Chaitali Nangia, Minal Barve, John Knecht, Jarrod Holmes, Kendrith Roland, Ralph Boccia, Frances Valdes-Albini, Zach Gostout, Mingjin Chang, William Williams, Charles Wiseman, Bonnie Guerin, Shaker Dakhil, Giuseppe Del Priore, Saranya Chumsri. Randomized Phase 2 of Bria-IMT, an Allogenic Human Cell Line with Antigen Presenting Activity, in Heavily Pretreated Metastatic Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-05-12.

Abstract Background: Bria-IMT (SV-BR-1-GM) is an off-the-shelf whole tumor cell therapeutic vaccine engineered to express class I & class II HLAs, secrete GM-CSF, and function as antigen-presenting cells; with subsequent enhancements improving in-vitro characteristics. By expressing cancer antigens such as HER2/Neu and PRAME, SV-BR-1-GM also serves as the reservoir of cancer antigens to activates patient’s anti-tumor immune responses. The safety and efficacy of the ongoing clinical trial of SV-BR-1-GM in combination with a PD1 inhibitor are reported. We also report post-hoc exploratory data for patients with advanced metastatic breast cancer (aMBC) treated with SV-BR-1-GM regimens. Methods: Ongoing prospective, phase 1-2, with an expansion randomized phase 2 cohort (NCT03328026; 2018-present) using SV-BR-1-GM with a PD1 inhibitor (pembrolizumab or retifanlimab) with cycles every 3 weeks (16 patients dosed to date). SV-BR-1-GM “monotherapy” (NCT03066947; 2013-8), a completed prospective phase 1-2 results are also presented. Results: A total of 51 patients received any SV-BR-1-GM regimen; 27 in monotherapy (SV) and 24 in combination with a PD-1 inhibitor (CO) currently ongoing: 4 subjects from SV continued on with CO. Median prior regimens = 5; 61% ER or PR+; 6% ER or PR-/HER2+ and 29% triple negative. SV-BR-1-GM was well tolerated. Disease control rate was 40% with SV and 41% with CO in subjects with available assessment(s). Median PFS was 2.7 months with 6 having PFS &gt;150 days (150-226) for SV and 2.6 months with 5 &gt; 150 days (188-308) for CO. Per protocol, 23 patients had anergy testing prior to treatment. Among those with a normal immunologic response (n=13, 56%), disease outcomes included 4 SD and 2 PR (46% CBR) vs anergic patients (n=7, 30%) with 1 SD (14% CBR); 3 patients (13%) with unknown anergy testing had 0% CBR. All 7 anergic patients developed delayed-type hypersensitivity (DTH) injection site responses to SV-BR-1-GM. Subjects with DTH (injection site induration/erythema) had a significant reduction in the risk of progression or death (HR=0.096, 95%CI:0.02-0.50, p&lt;0.05). Subjects with a reduction in circulating tumor cells (CTC) also had an improvement in PFS (HR 0.08, p=.0012). Median OS (uncensored) was 11.2 months in CO (n = 8). 7 out of 20 (35%) for SV and 9 out of 22 subjects (41%) for CO with available data, exceeded prior PFS. Among HLA matched subjects 4/7 (57%) and 6/9 (67%), respectively, had an increase in PFS. PFS ratio improved independent of prior number of lines, HER2 or HR status. The greatest improvement in PFS on a SV-BR-1-GM was in a HLA matched subject (&gt;6mo). TEAEs occurred in 20/24 (83%) of subjects in CO including 9/24 (38%) with injection site AEs. There were no AEs of special interest eg cytokine storm. There were no Grade 5 and only 6 grade 4 AEs in CO. Conclusions: In an ongoing randomized phase 2, anergic patients had worse outcomes. SV-BR-1-GM was able to illicit an immune response regardless. Responses, stable disease and CBR were seen and associated with immune responses including injection site erythema/induration (DTH), CTC changes and tumor grade I/II. Patients with disease control had better quality of life. SV-BR-1-GM may be able to alter an anergic immune system for clinical benefit. Future pivotal trials will be based upon the ongoing confirmatory randomized clinical trial. Citation Format: Saranya Chumsri, Minal Barve, Chaitali Nangia, Bonnie L. Guerin, Jarrod Holmes, Karim Mohammed, John Knecht, Shaker Dakhil, William V. Williams, Charles Wiseman, Mingjin Chang, Miguel Lopez-Lago, John G. Knecht, Kendrith Rowland, Ralph V. Boccia, Giuseppe Del Priore, Carmen Calfa. Whole cell antigen presenting immune stimulating cells (Bria-IMT) for the treatment of metastatic breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT143.

Abstract Background: SUMOylation, a post-translational modification analogous to ubiquitination, attaches a small, ubiquitin-like modifier (SUMO) to target proteins. SUMOylation plays a central role in the immune system by regulating type I interferon (IFN-I) expression, thereby functioning to constrain the innate immune response (Decque Nat Immunol 2016), and limit tumor immune surveillance. The SUMOylation pathway is often overexpressed in multiple myeloma (MM) and is associated with poor outcomes (Driscoll Blood 2010). TAK-981 is a first-in-class, small-molecule inhibitor of SUMO-activating enzyme, which blocks the SUMOylation cascade (Langston J Med Chem 2021) and increases IFN-I production and signaling in innate immune cells (Nakamura AACR 2019). In ex vivo assays, TAK-981 activated the IFN-I pathway, increased phagocytic activity of monocyte-derived macrophages, and increased natural killer (NK) cell cytotoxicity via IFN-I signaling (Nakamura AACR 2019). The ability of TAK-981 to promote activation of macrophages and NK cells provides a mechanistic rationale for its use in combination with monoclonal antibodies (mAbs) reliant on antibody-dependent cellular cytotoxicity and phagocytosis; in vivo experiments have demonstrated synergistic activity between TAK-981 and rituximab, and between TAK-981 and the anti-CD38 mAbs daratumumab (dara) (Nakamura SITC 2020) or mezagitamab (meza; TAK-079; Figure 1). Patients with MM who have disease refractory to the three most effective classes of anti-myeloma therapies (proteasome inhibitors [PIs], immunomodulatory drugs [IMiDs], and anti-CD38 mAbs) have a poor prognosis, with median survival 9.2 months (Gandhi Leukemia 2019). Given the incurable nature of advanced MM and the highly complex mechanisms of resistance, continued efforts to better understand MM biology at the time of relapse and to translate this into effective treatment combinations are needed. Combination therapies that engage the immune system to treat MM may offer substantial clinical benefit. Methods: To be eligible for this multicenter, open-label, Phase 1b/2 trial (NCT04776018), patients must have failed at least 3 prior lines of anti-myeloma therapy, have MM disease that is triple-class refractory (defined as refractory/intolerant to ≥1 PI and ≥1 IMiD, and refractory to ≥1 anti-CD38 mAb), and have demonstrated disease progression on their last therapy. Prior CAR-T therapy is allowed. Patients will be assigned to TAK-981 plus subcutaneous (SC) meza (Phase 1 Part 1) or SC dara (dara and hyaluronidase-fihj; Phase 1 Part 2). The primary objectives of Phase 1b are to determine safety and tolerability, and to select the recommended Phase 2 dose (RP2D) and schedule for TAK-981 with each mAb; secondary objectives are to evaluate preliminary antitumor activity, to characterize TAK-981 pharmacokinetics (PK), and to explore pharmacodynamic (PD) markers of TAK-981 target engagement and SUMOylation pathway inhibition. Approximately 30 patients will participate in the Phase 1b Part 1 dose escalation of TAK-981 plus meza (~15 patients per dosing schedule), and ~15 patients will participate in the Phase 1b Part 2 dose escalation of TAK-981 plus SC dara. The primary objective of Phase 2 is to evaluate the efficacy of TAK-981 at the RP2D in combination with an anti-CD38 mAb; ~36 patients will be enrolled. In Phase 1b, patients will receive TAK-981 via a 1-hour intravenous infusion either on days 1, 4, 8, 11, and 15 (twice weekly; BIW) or on days, 1, 8, 15, and 22 (weekly; QW) for 2x 28-day cycles, then 8x every other week, then monthly. Meza 600 mg SC or dara 1800 mg SC will be given 8x weekly, 8x every other week, then monthly, in a 28-day cycle (Figure 2). Treatment will continue until disease progression or unacceptable toxicity (max. 24 cycles). TAK-981 dose escalation will proceed from 60 mg BIW, a dose shown to be pharmacologically active in a first-in-human, single-agent TAK-981 study (TAK-981-1002; data on file). Dose escalation will be guided by Bayesian Optimal Internal Design with Informative Prior (iBOIN) plus consideration of other safety, clinical, PK, and PD data. The iBOIN design selects the true maximum tolerated dose (if any) with high accuracy by allocating more patients to dose levels with a prior dose-limiting toxicity probability closest to the target of 0.3. This study is currently enrolling patients, with the first patient dosed in May 2021. Figure 1 Figure 1. Disclosures Lonial: AMGEN: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; GlaxoSmithKline: Consultancy, Honoraria, Research Funding; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; BMS/Celgene: Consultancy, Honoraria, Research Funding; Merck: Honoraria; Abbvie: Consultancy, Honoraria. Boccia: BMS: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Abbvie: Consultancy, Honoraria, Speakers Bureau; Takeda: Honoraria, Research Funding, Speakers Bureau; Amgen: Research Funding, Speakers Bureau; Epizyme: Honoraria, Speakers Bureau; Morphosis: Honoraria, Speakers Bureau. Yimer: Beigene: Speakers Bureau; Astrazeneca: Speakers Bureau; Karyopharm: Current equity holder in publicly-traded company, Speakers Bureau; Janssen: Speakers Bureau; GSK: Speakers Bureau; Sanofi: Speakers Bureau; Amgen: Speakers Bureau; Pharmacyclics: Speakers Bureau; Texas Oncology: Current Employment. Levy: Jazz Pharmaceuticals: Consultancy, Honoraria, Speakers Bureau; Morphosys: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; Karyopharm: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; Dova: Consultancy, Other: Promotional speaker; Janssen Pharmaceuticals: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; Amgen Inc.: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; GSK: Consultancy, Other: Promotional speaker; Epizyme: Consultancy, Other: Promotional speaker; Novartis: Consultancy, Other: Promotional speaker; AbbVie: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; Beigene: Consultancy, Honoraria, Speakers Bureau; Bristol Myers Squibb: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; Gilead Sciences, Inc.: Consultancy, Honoraria, Speakers Bureau; Seattle Genetics: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; Takeda: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; TG Therapeutics: Consultancy, Honoraria, Speakers Bureau. Abonour: Takeda: Research Funding; GSK: Consultancy, Honoraria, Research Funding; Celgene-BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jensen: Honoraria, Research Funding. Mohan: Medical College of Wisconsin: Current Employment. Girnius: BMS: Honoraria, Speakers Bureau; Celgene: Speakers Bureau; Genentech: Honoraria; GSK: Honoraria, Speakers Bureau; Takeda: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Beigene: Speakers Bureau. Rosenbaum: Takeda: Honoraria; Akcea: Honoraria; Janssen: Honoraria. Nadeem: Karyopharm: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees. Berg: Takeda: Current Employment, Current equity holder in publicly-traded company, Current holder of stock options in a privately-held company. Chao: Takeda: Current Employment. Berger: Takeda Development Center Americas, Inc.: Current Employment. Nakamura: Takeda Development Center Americas, Inc.: Current Employment. Zhang: Takeda: Current Employment. Song: Takeda Pharmaceuticals International Co.: Current Employment. Ward: Takeda: Current Employment. Proscurshim: Takeda Pharmaceuticals: Current Employment, Current holder of individual stocks in a privately-held company. Kumar: Novartis: Research Funding; Tenebio: Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Antengene: Consultancy, Honoraria; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche-Genentech: Consultancy, Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Research Funding; Beigene: Consultancy; Bluebird Bio: Consultancy; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Research Funding; Oncopeptides: Consultancy; Amgen: Consultancy, Research Funding; Carsgen: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding. OffLabel Disclosure: Study of the investigational agent TAK-981 in combination with daratumumab and hyaluronidase-fihj or the investigational agent mezagitamab (TAK-079).

Abstract In the phase 3 ENDEAVOR study, carfilzomib-dexamethasone (Kd) improved survival over bortezomib-dexamethasone (Vd) in patients with relapsed or refractory multiple myeloma (RRMM), regardless of baseline renal function. This real-world study compared renal response in patients with RRMM (1-3 prior lines) and renal impairment (estimated glomerular filtration rate ≤50 mL/min) treated with Kd vs Vd. Electronic medical records data from the Oncology Services Comprehensive Electronic Records database were assessed (from January 2012 through February 2018). Time to renal response (defined according to International Myeloma Working Group criteria) was evaluated using the Kaplan-Meier method and log-rank test. Incidence rate ratios (IRRs) and 95% confidence intervals (CIs) were calculated for renal overall response (ROR) and renal complete response (RCR) using Cox proportional hazard models adjusted for baseline covariates. Included were 543 Kd-treated and 1005 Vd-treated patients. In line 2 (2L), compared with Vd, Kd achieved significantly higher ROR (51.4% vs 39.6%; P &lt; .0001) and RCR (26.6% vs 22.2%; P = .0229). After baseline covariate adjustment, 2L patients receiving Kd vs Vd were 45% more likely to achieve ROR (IRR, 1.45; 95% CI, 1.18-1.78), and 68% were more likely to achieve RCR (IRR, 1.68; 95% CI, 1.24-2.28). The renal response benefit with Kd remained consistent in 2L to line 4 (4L). In a combined analysis of patients receiving Kd and Vd (2L and 2L-4L), renal responders had longer overall survival and time to next treatment than renal nonresponders. These results demonstrate improved real-world effectiveness of Kd over Vd in RRMM renal rescue, and the positive association between renal response and improved survival.

Abstract Background: Phlebotomy to maintain hematocrit <45% is considered one of the cornerstones for the management of polycythemia vera (PV). However, phlebotomy procedures may be inconvenient for or poorly tolerated by some patients, and often result in iron deficiency, which may be associated with additional quality-of-life burden, such as fatigue, impaired cognitive function and restless leg syndrome. The REVEAL study (ClinicalTrials.gov, NCT02252159) is being conducted to describe contemporary demographics, burden of disease, clinical management, patient-reported outcomes, and healthcare resource utilization among patients with PV in the US. This early analysis describes the patient self-reported burden of phlebotomy at the time of enrollment. Methods: REVEAL is a multicenter, noninterventional, nonrandomized, prospective, observational study of adult patients with PV who are currently under the care of a US physician. REVEAL collects physician assessments and patient-reported outcomes during a 36-month observation period. Phlebotomy-related burden is being assessed with a new 21-item phlebotomy burden questionnaire (PBQ-21) at enrollment and every 90 days thereafter; it assesses patient-reported phlebotomy frequency, practice setting, time required for phlebotomy, inconvenience, and phlebotomy-related adverse effects. Phlebotomy-related effects and bother/inconvenience (if experienced within 24 hours after a phlebotomy procedure) are graded on a 4-point scale of 1 (not at all) to 4 (extremely). Analyses of these preliminary data were descriptive. Results: At the time of data cutoff, 865 patients were enrolled (total planned enrollment, n=2000). Median age was 67 (range, 22-95) years, 55.5% were male, and 89.5% were white. Median time from PV diagnosis to study enrollment was 53 months. Overall, 748 patients completed the PBQ-21 at enrollment and 400 (53.5%) had received a phlebotomy within 3 months prior to enrollment. Mean number of phlebotomies in the past 3 months was 2.2 (SD, 1.7). Phlebotomy was most commonly performed at a doctor's office during a regular medical visit (37.8%), at an infusion center or special cancer care center (26.8%), or at a hospital (18.3%). Patients who had phlebotomy procedures within 90 days before enrollment reported a mean total treatment time of 4.2 (SD, 4.7) hours per phlebotomy procedure; for employed patients, the mean amount of work time missed was 4.6 (SD, 15.6) hours per procedure. Fatigue, bruising, dehydration, and dizziness were among the most commonly reported adverse effects of phlebotomy (Table 1). Twenty percent of patients reported that phlebotomy procedures were moderately or extremely bothersome, inconvenient (18.3%), or painful or physically uncomfortable (16.3%). Furthermore, some patients (8.8%) reported that their family and friends were moderately or severely inconvenienced by phlebotomy procedures. Conclusion: The PBQ-21 collects important and relevant patient-reported information to systematically assess the impact of phlebotomy on patients and caregivers. From the early view of REVEAL enrollment data, a considerable proportion of patients reported fatigue, bruising, dehydration, and dizziness resulting from phlebotomy procedures. Furthermore, patients reported spending a considerable amount of time (4 hours on average) per phlebotomy procedure, which is a sizeable burden for patients who are employed. In addition, some patients reported that phlebotomy procedures may be inconvenient, painful or uncomfortable, and bothersome. REVEAL provides important information for providers to understand and address when to prescribe phlebotomy for patients with PV. Disclosures Boccia: Incyte Corporation: Honoraria. Stein:Incyte Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees. Mesa:Genentech: Research Funding; Promedior: Research Funding; NS Pharma: Research Funding; CTI Biopharma: Research Funding; Gilead: Research Funding; Incyte Corporation: Research Funding; Novartis Pharmaceuticals Corporation: Consultancy; Pfizer: Research Funding. Naim:Incyte Corporation: Employment, Equity Ownership. Cordaro:Incyte Corporation: Employment, Equity Ownership. Peng:Incyte Corporation: Employment, Equity Ownership. Sun:Incyte Corporation: Employment, Equity Ownership. Parasuraman:Incyte Corporation: Employment, Equity Ownership. Moliterno:Incyte Corporation: Membership on an entity's Board of Directors or advisory committees.