Prior Lines Of Therapy Research Articles

Erythrocyte-αPD-1 conjugates overcome resistance to checkpoint blockade immunotherapy: A first-in-human study.

2557 Background: While the immune checkpoint blockade (ICB) therapy has revolutionized the field of tumor therapy. the resistance remains a major challenge. We have previously developed WTX-212, an erythrocyte-antibody conjugate covalently linking anti-PD-1 antibody to erythrocyte membranes. Unlike conventional antibodies, WTX-212 exhibits natural accumulation in the spleen and remodels the splenic immune landscape in tumor-bearing mice. WTX-212 treatment efficiently activates CD8+ T cells in the spleen, which subsequently infiltrate into tumors and exhibit anti-tumor cytotoxicity. Additionally, activated T cells reduce the splenic reservoir of Myeloid-derived suppressor cells (MDSC) and those within tumors, further enhancing overall anti-tumor responses. Pre-clinical studies have demonstrated that WTX-212 can significantly suppress tumor growth in xenograft tumor models resistant to anti-PD-1 immunotherapies. A first-in-human (FIH) clinical trial is now investigating its potential in human cancer patients. Methods: The FIH trial (NCT05707325) is aimed to investigate the safety, pharmacokinetics and preliminary efficacy of WTX-212 in cancer patients with advanced malignancies. All of patients had previously received anti-PDs therapies and developed resistance to these treatments. By Feb 5th, 2024, the tumor lesions were assessed using RECIST v1.1 criteria. Blood and tumor samples were collected for correlative analysis. Results: 7 metastasized patients with various solid tumors, having undergone a median of 3.1 prior lines of therapy (ranging from 1-6), received WTX-212 monotherapy. None of patients treated with WTX-212 experienced treatment-related adverse events greater than Grade 3, indicating a high safety profile. WTX-212 was detectable in peripheral blood at the end of cycle in a dose dependent manner. Disease control was achieved in 5/7 patients (DCR=71%). Specifically, a patient with esophageal cancer, achieved a confirmed complete remission after 6-cycle treatment. Additionally, two patients, one with esophageal cancer (3L) and another with HPV-negative cervical cancer (4L), maintained stable disease for over 40 and 30 weeks, respectively. Consistent with our pre-clinical findings, a substantial reduction in MDSCs were observed in 6/7 patients (ranging from 24%-82%). Furthermore, a median 1.5-fold increase in T cells was noted in all patients in the peripheral blood after the 1st cycle of the treatment. Conclusions: WTX-212 treatment is safe and tolerable and shows promising clinical signs in cancer patients resistant to anti-PD-1 immunotherapy, supporting further investigation and exploration of WTX-212 monotherapy and combination therapy. Clinical trial information: NCT05707325 .

Real-world understanding of the unmet need for treatment of non-covalent BTKi in chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL).

e19028 Background: Non-covalent (nc) Bruton Tyrosine Kinase inhibitors (BTKi) for the treatment of Chronic Lymphocytic Leukemia and Small Lymphocytic Lymphoma (CLL/SLL) provide patients with a new treatment option after resistance to on-target BTK mutations or PLCγ2 mutations that bypass BTK inhibition. Given the December 1, 2023 accelerated FDA approval for pirtobrutinib, a nc-BTKi, in the treatment of CLL/SLL for treatment of patients who have received at least two prior lines of therapy with a covalent (c) BTKi and a B-Cell Lymphoma 2 Protein Inhibitor (BCL2i), we sought to understand the addressable population for treatment with nc-BTKI therapy in a real-world database of CLL/SLL patients. Methods: We used the Integra Connect PrecisionQ real-world de-identified database of over 3 million cancer pts across 500 sites of care to identify CLL/SLL pts for the analysis. The CLL patients included for the analysis were on a treatment in 2023 and must have had either >5 CLL/SLL diagnosed visits or more CLL/SLL visits than non-CLL/SLL visits if <5 CLL/SLL diagnosed visits. Descriptive analyses were used for this study. Results: Of the 6,992 patients treated for CLL/SLL in 2023, the median age at treatment start was 71, 62% were male, 65% identified as White, 6% as African American, and 29% as Other. Of the pts, 12% received a c-BTKi and BCL2i, 64% received a c-BTKi only, and 12% received a BCL2i only. Of the 12% of pts who received a c-BTKi and BCL2i, 191 pts started a subsequent line of therapy. Among pts who received a c-BTKi and BCL2i, 79% received a BTKi therapy first, 10% received a BCL2i therapy first, and 12% had a line of therapy with both a BTKi and BCL2i. We found 59 pts who received nc-BTKi; among those pts, 51% received a c-BTKi and BCL2i prior to initiation of nc-BTKi. The median age at first treatment for CLL/SLL was 71.7 for those who received a c-BTKi, 71.1 for those who received a BCL2i, and 70.8 for those who received nc-BTKi. The median age at first diagnosis for CLL/SLL was 68 for those who received a c-BTKi, 66 for those who received a BCL2i, and 63 for those who received nc-BTKi. The median time to first treatment was 470 days for pts treated with a c-BTKi, 507 days for pts treated with BCL2i, and 587 days for pts treated with nc-BTKi. Conclusions: We found that among nearly 7,000 treated patients in the database, 12% were treated with both a c-BTKi and BCL2i; of those, just 23% started a subsequent treatment. Among patients who were treated with a nc-BTKi we found their median age at treatment start and diagnosis was lower than those who received a c-BTKi or BCL2i respectively.

Phase 1/2 trial of the XPO1 inhibitor selinexor in combination with docetaxel in previously treated, advanced KRAS mutant non-small cell lung cancer (NSCLC).

8597 Background: KRAS mutant NSCLC remains a therapeutic challenge. Although KRAS G12C inhibitors are now approved for cases harboring that specific mutation, their efficacy is modest and the G12C variant accounts for only 40% of KRAS mutations in NSCLC. To date, there are no approved targeted therapies for non-G12C KRAS mutant NSCLC. Selective inhibitors of nuclear export (SINE) modulate cancer cell biology by retaining certain proteins—such as tumor suppressors—within the nucleus, where they remain physiologically active. The XPO1 inhibitor selinexor demonstrated efficacyinpreclinicalNSCLC models harboring various KRAS mutations. Methods: In this 3 + 3 dose-escalation phase 1/2 trial, patients with previously treated advanced KRAS mutant NSCLC received selinexor (dosed orally weekly) plus docetaxel 75 mg/m2 IV every three weeks (NCT03095612). Prior treatment with KRAS G12C inhibitors was permitted. Results: Among 40 enrolled patients, median age was 66 years, 22 (55%) were female, and 34 (85%) were white. KRAS mutation types included G12C (28%), G12V (23%), G12D (20%), G12A (13%), G12R (5%), G13C (5%), and one case each of G12S, G13D, Q61L, and K117N. Patients had received a median of 2 prior lines of therapy (range 1-4). The maximum tolerated dose of selinexor was 60 mg PO weekly combined with docetaxel. The most common adverse events (AE) were nausea (73%, Gr ≥3 8%), fatigue (70%, Gr ≥3 5%), neutropenia (65%, Gr ≥3 60%), diarrhea (58%, Gr ≥3 10%), anorexia (50%, Gr ≥3 0%), and vomiting (45%, Gr ≥3 5%). Of 32 patients evaluable for efficacy, 7 (22%) had partial response (PR) and 18 (56%) had stable disease (SD) as best response. Median progression-free survival (PFS) was 4.1 months (95% CI, 2.9-5 months); median overall survival (OS) was 7.1 months (95% CI, 4.5-13.7 months). Clinical outcomes did not differ significantly among KRAS mutation types. However, TP53co-mutations (48%) were associated with significantly worse outcomes: disease control rate (PR + SD) 27% vs 92% ( P=0.006); median PFS 1.8 vs 7.4 months ( P<0.001); median OS 5.8 vs 17 months ( P=0.006). Additional biomarker studies are ongoing. Conclusions: Selinexor plus docetaxel is tolerated with multi-agent supportive care. The combination shows moderate efficacy across KRAS mutation types, with promising activity in TP53 wild type cases. Clinical trial information: NCT03095612 .

A phase 1 study to evaluate the safety, pharmacokinetics (PK), and pharmacodynamics (PD), and to determine the recommended phase 2 dose (RP2D) of subcutaneous (SC) cetrelimab (CET) in patients (pts) with advanced solid malignancies.

e14602 Background: In part (P) 1 and P2 of LUC1001 (NCT02908906), the RP2D of intravenous (IV) CET was established as 240 mg IV once every 2 weeks (Q2W) or 480 mg IV Q4W, and the PK/PD characteristics, safety profile, and clinical activity were consistent with known and approved PD-1 inhibitors (Felip et al. Cancer Chemother Pharmacol 2022). CET administered SC was investigated in P3 and P4 of LUC1001. Methods: In P3 and P4 of LUC1001, safety, PK, PD, and clinical activity of low- (30 mg/mL [CET-LC]) and high- (150 mg/mL [CET-HC]) concentration SC CET formulations, respectively, were evaluated. Key entry criteria were advanced or refractory solid tumors, previous receipt of or ineligibility for standard treatment, and being anti-PD-1/PD-L1/2–naïve. In P3, SC CET-LC injection was administered at a dose level of 600 mg with a 6-week dosing interval between doses 1 and 2, then Q3W dosing after dose 2. In P4, SC CET-HC injection was administered as a single loading dose of 900 mg, followed by 600 mg Q3W. Results: Among 30 enrolled pts (P3: n = 11; P4: n = 19), median age was 54.5 years; 17 (57%) were male; most (29 [97%]) were White and heavily pretreated, with a median of 3 (range, 1-8) prior lines of therapy. Most common tumor types were colorectal cancer (6 [20%]), breast cancer (4 [13%]), cholangiocarcinoma and NSCLC (3 [10%] each). Most commonly reported adverse events (AE) were fatigue (11 [37%]), ALT increased (7 [23%]), abdominal pain, constipation and AST increased (6 [20%] each). Overall, 20 (67%) pts had CET-related AEs, 1 (3%) of which led to CET discontinuation. Eight (27%) pts had ≥1 CET-related ≥Grade 3 AE. Immune-related AEs were reported in 9 (30%) pts. No pts experienced systemic-administration–related reactions, and 2 (6%) pts experienced Grade 1 administration-site reactions. No CET-related serious AEs were reported. Durable responses were observed in 2 (7%) patients (cholangiocarcinoma in P3 and thymoma in P4). Stable disease ≥24 weeks was observed in 4 (13% [P3, 0 (0%); P4, 4 (21%)]) pts. According to PK data, the 900-mg SC CET loading dose followed by 600-mg SC CET Q3W would likely result in comparable exposure as observed at steady state with IV RP2Ds. No differences in PK, including absorption, were observed between CET-LC and CET-HC formulations. Maximum PD-1 receptor occupancy was achieved, consistent with historical IV and SC data. Incidence of anti-CET antibodies (P3, 3/11 [27%]; P4, 0/13 [0%]) was low, and no neutralizing antibodies (0/24 [0%]) were detected. Conclusions: SC CET demonstrated a safety profile similar to IV CET. Based on safety, PK, and PD data, the RP2D of SC CET was established as a loading dose of 900 mg followed by 600 mg Q3W. Studies are planned to further evaluate the safety and efficacy of SC CET in combination with other agents. Clinical trial information: NCT02908906 .

A phase II, multicenter, open-label study of polyPEPI1018 in combination with atezolizumab in participants with relapsed or refractory microsatellite-stable metastatic colorectal (MSS mCRC) cancer (Oberto-301).

3594 Background: The efficacy of checkpoint inhibitor immunotherapy in MSI-H mCRC has not been replicated in MSS mCRC. Therefore, additional interventions are needed to convert immunologically “cold” MSS CRC to “hot” tumors resembling MSI-H tumors. PolyPEPI1018 is an off-the-shelf, multi-peptide vaccine containing 12 immunogenic epitopes derived from 7 shared tumor antigens which demonstrated early evidence of clinical activity in first-line MSS mCRC. Methods: Patients with MSS mCRC who have progressed on 2-3 lines of prior chemotherapy regimen received PolyPEPI1018 (1.2 mg, sc) and atezolizumab (1,200 mg, iv) Q3W until disease progression or unacceptable toxicity. The primary endpoint was safety. A Simon 2-stage design was applied. Data on objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS) and correlation studies will be presented. Results: 18 patients (66 % female) were enrolled for stage 1 of the study. Median age was 54 years (range 38–79), 50% had liver metastases and 67% received at least 3 lines of prior therapies. PD-L1 expression was <1% for 85% of patients. The combination was well-tolerated; most common side effect related to treatment was Grade (Gr) 1-2 local skin reaction (n=22). Gr 2 events (n=2) at least possibly related to treatment were nausea, pyrexia and increased blood alkaline phosphatase. There were no Gr 3-5 events or study discontinuation due to treatment AE. The ORR was 0% and the DCR was 61%. The mPFS was 2.7 months (95%CI 1.4-4.0) and the mOS was not reached (95%CI 8.75 – NE months) at the data cut-off date. Ex-vivo FluoroSpot identified 13/16 subjects with robust, vaccine-specific CD8+ and/or CD4+ T cell responses detected against multiple vaccine antigens. For patients with available biopsy pairs (n=8), both the average PD-L1 expression (IC%, p=0.029) and the density of CD8+ tumor-infiltrating lymphocytes (TILs, p=0.019) were significantly increased, post-treatment. Patients with increased PFS (> 12 weeks) had both higher levels of post-treatment PD-L1 (p=0.007) and TILs (p=0.016) than patients with PFS ≤ 12 weeks. Conclusions: PolyPEPI1018 in combination with atezolizumab was well-tolerated with no Grade 3 AEs observed. Despite no objective tumor responses could be detected, correlative data suggest contribution of PolyPEPI1018-induced immune responses to the modulation of tumor microenvironment and to improved disease control. The study did not proceed to stage 2; it is on-going for the collection of survival data. Clinical trial information: NCT05243862 .

A phase II multicenter study of abexinostat, an oral histone deacetylase inhibitor, in patients with relapsed/refractory follicular lymphoma.

7059 Background: Epigenetic alterations are major drivers of Follicular lymphoma (FL). Histone deacetylase (HDAC) inhibitors have potential to counteract the loss of histone acetylation that results from CREBBP or EP300 mutations. Abexinostat (Abx) is a novel potent oral pan-HDAC inhibitor with a pharmacokinetic profile that allows maintenance of sufficient drug concentrations for anti-tumor activity with twice daily (BID) dosing. Abx was shown to be well-tolerated with significant response in pts with relapsed/refractory (R/R) FL. Methods: This phase Ⅱ study evaluated Abx 80 mg administered orally BID 4 hours apart in a “one week on, one week off” schedule (days 1 to 7 & 15 to 21 of a 28-day cycle) in pts with R/R FL (grade 1-3a). Key inclusion criteria included age ≥18 years, ≥ 2 prior treatment regimens, ECOG of 0-2, and measurable disease per Lugano 2014 criteria. Pts undergo efficacy assessment by enhanced CT/MRI every 8 weeks for the first 24 weeks, and every 12 weeks thereafter, and PET-CT at weeks 12 and 24 and to confirm a complete response (CR), in accordance with the Lugano 2014 criteria. Bone marrow (BM) evaluation was mandated in pts with baseline BM involvement who achieved radiographic CR. The primary endpoint is independent review committee (IRC)-assessed overall response rate (ORR). Secondary endpoints include duration of response (DoR), progression-free survival (PFS), overall survival (OS), and safety. Results: At the data cut-off date of December 15, 2023, data were available for 90 pts. Median age was 55.0 (range 27-79), 57.8% of pts were male, and 22.2% had ≥ 3 FLIPI-2. Pts had a median of 3 prior lines of therapy (range 2-9), and 24.4% were refractory to the last prior regimen, 27.8% of pts had been treated with PI3K inhibitors before. With a median follow-up of 20.8 months, of 82 pts evaluable for efficacy, the IRC-assessed ORR was 67.1% (95% CI: 55.8%-77.1%), including 12.2% CR. The ORR for pts with > 3 lines of prior therapy was 69.0% (95% CI: 49.2%-84.7%). The median PFS and median DoR was 13.77 (95% CI: 9.69-not evaluable [NE]) months and 13.96 (95% CI: 8.34-NE) months, respectively. Median OS was not reached, and the 42-month OS rate was 74.3% (95% CI: 58.1%-85.0%). Of 90 pts evaluable for safety, the most common (≥ 40%) treatment-emergent adverse events (TEAEs) were thrombocytopenia (85.6%), neutropenia (58.9%), leukopenia (52.2%), nausea (50.0%), anemia (48.9%) and diarrhea (46.7%); ≥grade 3 TEAEs (≥ 5%) included thrombocytopenia (37.8%), neutropenia (23.3%), leukopenia (7.8%), and lymphopenia (5.6%). TEAEs led to dose reductions and discontinuations in 28.9% and 3.3% of all pts, respectively. Conclusions: Abx was well tolerated at dose of 80 mg BID as monotherapy, and demonstrated a significant response in pts with heavily pretreated R/R FL. Clinical trial information: NCT03934567 .

Real-world analysis of belantamab mafodotin (belamaf): Care patterns in relapsed/refractory multiple myeloma.

e19507 Background: Belamaf is an anti-B cell maturation antigen immunoconjugate for relapsed/refractory multiple myeloma that has shown efficacy and safety in the DREAMM clinical trials. Additional long-term real-world data on its use patterns, efficacy, and tolerability are needed. Methods: This retrospective review (NCT05986682) analyzed adults with multiple myeloma receiving ongoing care at Duke Cancer Institute who began belamaf monotherapy (not in a clinical trial) between 8/5/2020 and 11/22/2022. We abstracted data for 30 patients through 9/18/2023. We described baseline clinical characteristics, disease response (per International Myeloma Working Group [IMWG] criteria, as possible given available marrow biopsy data), belamaf use patterns, and ocular adverse events (AEs) (per the Keratopathy Visual Acuity [KVA] scale). Results: Our sample was 53% (n=16) female, 47% (14) White, and 47% (14) Black; median age was 68 years at the beginning of belamaf therapy. 67% (20) had ≥4 prior lines of therapy (median: 4, min-max: 2-19), 87% (26) were triple-/quad-/penta-refractory, and 23% (7) had high-risk cytogenetics (per IMWG). Overall response rate (ORR) was 67% (11 very good partial response, 9 partial response). Median (min-max) time to best response was 1.5 (0.7-9.9) months. Median (min-max) response duration was 9.8 (1.1-20.2) months. Progression occurred in 73% (22) of patients; median progression-free survival (PFS) was 8.4 months (95% CI 6.6-12.7). Median overall survival was not reached. Median (min-max) number of cycles was 6.5 (2-13). 63% of patients (19) had a dose reduction from 2.5 to 1.9 mg/kg; 65% (13) were due to corneal AEs and 30% (6) due to hematologic AEs. 93% (28) had ≥1 cycle delay, and the median (min-max) number of delays was 5 (1-14); 85% of delays (n=153) were due to corneal AEs. Cycle length changed for 33% (10) from every 3 weeks to every 4 (1) or 6 (9) weeks; 91% (n=10) of cases were due to corneal AEs. 93% (28) had keratopathy (any grade); among all events (n=323), 2% were grade ≥3. Median (min-max) time to resolution of grade ≥2 keratopathies was 6 (2-22) weeks. 90% (27) experienced a visual acuity change; among all events (n=244), 3.3% were grade ≥3. Median (min-max) time to resolution of grade ≥2 visual acuity events was 6 (2.9-53) weeks. The most common ocular symptoms were blurry vision (53% of symptoms), dry eyes (17%), and photophobia (14%). Belamaf was discontinued in 13% (4) due to ocular AEs and 20% (6) to patient/physician choice or other reason. Median (min-max) time to last dose/discontinuation was 9.3 (0.7-21.6) months. Conclusions: In our study, ORR and median PFS were greater than other real-world studies. Corneal AEs were also more common, but severity was consistent with these and DREAMM-3 findings. Despite a higher rate of dose reductions and delays than other real-world studies, our study adds promise to the benefit of belamaf over an extended time with dose modifications.

First-in-human phase I/II safety and preliminary efficacy of PM1032, a bispecific antibody targeting CLDN18.2 and 4-1BB, in patients with advanced solid tumors.

2662 Background: PM1032 is an anti-CLDN18.2 x 4-1BB bispecific antibody that activates immune cells, such as T and NK cells, via CLDN18.2-mediated crosslinking of 4-1BB. Potent anti-tumor efficacy is facilitated with limited toxicity as immune activation is only stimulated in the context of CLDN18.2 expression on target cells. Here, we present the preliminary safety and efficacy results from an ongoing Phase I/II trial, which is a first-in-human (FIH), dose-escalation, and expansion study of PM1032 in patients (pts) with advanced solid tumors. Methods: This FIH study of PM1032 with adults with previously treated, advanced or metastatic solid tumors includes dose escalation (3+3 design; regardless of CLDN18.2 expression) and dose expansion stages (CLDN18.2+ gastrointestinal (GI) cancers). During the dose escalation stage, PM1032 was administered at doses of 0.3, 1, 3, 5, 8 and 12 mg/kg for the assessment of drug limiting toxicity (DLT) after 3 weeks, followed by administration Q2W until disease progression (PD) or observations of intolerable toxicity. Responses were evaluated according to RECIST 1.1. Adverse events (AEs) were graded using CTCAE v5.0. CLDN18.2 positivity was defined as ≥1% of tumor cells with ≥1+ signal intensity by immunohistochemistry. Results: As of January 12, 2024, a total of 30 pts received PM1032 (18 pts during dose escalation and 12 pts during dose expansion) with no DLTs observed (median age 54y; most pts had ≥2 metastatic sites). CLDN18.2 expression was evaluable in 80% of the pts and 66.7% were positive. The most common tumor types were GI cancers including 14 gastric and gastroesophageal junction cancers (GC/GEJ), 10 pancreatic adenocarcinoma (PDAC) and 5 other GI cancers. All pts had ≥1 line of prior therapy and 17 pts (56.7%) had prior immunotherapy. TRAEs occurred in 22 subjects (73.3%), and ≥ Grade 3 TRAEs occurred in 3 subjects (10%). The most common TRAEs were nausea (20%) and aspartate transaminase increase (16.7%). Among a total of 16 CLDN18.2+ pts enrolled at the 5, 8, and 12 mg/kg dose levels who completed at least one tumor evaluation, 2 pts achieved PR, 7 pts had SD and 3 pts were Non-CR/Non-PD. Additionally, the ORR was 20% in 10 measurable and evaluable CLDN18.2+ GC/GEJ pts. The longest treatment duration was 18 months and 5 pts had treatment durations ≥ 6 months. Pharmacokinetics (AUC0-336h & Cmax) were dose-proportional across the dose ranges of 0.3 mg/kg – 12 mg/kg with a terminal half-life of 6.0~10.1 days. Conclusions: PM1032 was well-tolerated up to 12 mg/kg Q2W and demonstrated preliminary anti-tumor activity in CLDN18.2+ tumors. Further development of PM1032 as a monotherapy and/or combination therapy for CLDN18.2-positive cancers is planned. Clinical trial information: NCT05839106 .

Evaluation of the safety, pharmacokinetics, and efficacy of JSKN003 in patients with advanced solid tumors: A phase I/II clinical study.

3031 Background: JSKN003 is a bispecific HER2-directed antibody-drug conjugate (ADC) conjugated to a topoisomerase I inhibitor via a dibenzocyclooctyne tetrapeptide linker on the glycan of a humanized bispecific antibody. Pre-clinical studies showed that JSKN003 had a good serum stability, that may lead to a broader therapeutic window. Methods: JSKN003-102 (NCT05744427) is a phase I (dose escalation and dose expansion) and phase II (cohort expansion) study in Chinese patients (pts) with advanced solid tumors. Pts (ECOG PS 0-1) with HER2-expressing (IHC ≥ 1+) or HER2-mutant cancers who failed prior systemic therapies were recruited and received JSKN003 monotherapy intravenously Q3W. The objectives were safety, MTD or RP2D, pharmacokinetics, and preliminary antitumor activity. Here the results from phase I were reported. Results: As of 5th Jan 2024, 46 pts (25 breast cancers, 11 gastric cancers, 8 colorectal cancers, 1 lung cancer, and 1 ovarian cancer) were enrolled and received JSKN003 across 6 dose levels, including 2.1 (n=1), 4.2 (n=10), 5.2 (n=14), 6.3 (n=15), 7.3 (n=3), and 8.4 mg/kg (n=3), Q3W, in phase I period. Among the 46 pts, 18 were IHC 3+, 21 were IHC 2+, and 7 were IHC 1+. Most pts (73.9%) received ≥ 3 prior lines of therapy, including 60.9% and 45.6% of pts received prior anti-HER2 and anti-HER2 ADC therapy, respectively. The median duration of treatment was 13.1 (range, 2.1 - 42.4) weeks, and 37 pts (80.4%) remained on treatment. Treatment-related adverse events (TRAEs) occurred in 44 pts (95.7%), and the common, mostly grade 1 and 2, were diarrhea (37.0%) and nausea (32.6%). Only 6 pts (13.0%) experienced grade ≥3 TRAEs, and the common were lymphopenia (4.3%) and neutropenia(4.3%). 1 pt (2.2%) had treatment related SAE (nausea, grade 3). No pts experienced DLT or interstitial lung disease, and no TRAE led to death or discontinuation. Following a single dose, exposures (Cmax and AUC) of JSKN003 increased proportionally over a dose range of 4.2 mg/kg to 6.3mg/kg. T1/2 of JSKN003 is approximately 3-5 days. No significant accumulation was observed after 4 cycles treatment. The exposure of released payload was very low, demonstrating the stability of the JSKN003 in circulation. 37 pts had at least one post-baseline tumor assessment. The ORR and DCR was 51.4% (95%CI: 34.4, 68.1) and 91.9% (95%CI: 78.1, 98.3), respectively. The ORR in pts with HER2 IHC 1+, 2+ and 3+ was 20.0% (95% CI: 0.5, 71.6), 33.3% (95% CI: 11.8, 61.6), and 76.5% (95% CI: 50.1, 93.2), respectively. For pts who received prior anti-HER2 ADC, the ORR was 57.9% (95% CI: 33.5, 79.7). For HER2 positive breast cancer and gastric cancer, the ORR was 66.7% (95% CI: 38.4, 88.2) in 15 pts and 100% (95% CI: 39.8, 100) in 4 pts, respectively. Conclusions: MTD of JSKN003 was not reached yet. And safety of JSKN003 was extremely excellent with encouraging preliminary antitumor activity in heavily pretreated pts with advanced solid tumors. Clinical trial information: NCT05744427 .

Mosunetuzumab with polatuzumab vedotin: Subgroup analyses in patients (pts) with primary refractory or early relapsed large B-cell lymphoma (LBCL).

7021 Background: The primary analysis of mosunetuzumab with polatuzumab vedotin (mosun-pola) in the Phase Ib/II study (NCT03671018) demonstrated durable responses and manageable safety in pts with relapsed or refractory (R/R), transplant-ineligible LBCL (Budde et al. Nat Med 2023). Here, we present results for primary refractory (refr) or early relapse (rel) subgroups from this study after a median follow-up of 23.9 months. Methods: Pts with R/R LBCL (diffuse LBCL not otherwise specified [NOS], high-grade B-cell lymphoma [HGBCL], transformed follicular lymphoma (FL), and FL grade 3b) and who received ≥1 prior line of therapy (including an anti-CD20 antibody) were treated with mosun-pola. Refr was defined as SD, PD, PR, or CR with relapse <3 months after first-line (1L) therapy. Rel was defined as CR with relapse ≥3 and ≤12 months after 1L therapy. The primary endpoint was best overall response rate (ORR) by IRC using Lugano 2014 response criteria. Key secondary endpoints included CR rate, duration of response (DOR), duration of CR (DOCR), progression-free survival (PFS), overall survival (OS), and safety. Results: As of July 6, 2023, of the 98 pts in the overall population, 45 (46%) and 27 (28%) pts had refr or rel LBCL, respectively. At baseline, the median age in the refr and rel subgroups was 68 and 70 years respectively; 23/45 pts (51%) and 6/27 pts (22%) were treated with mosun-pola as second-line, respectively. The majority of refr/rel pts had DLBCL NOS (71%; 78%) or HGBCL (24%; 19%), Ann Arbor stage III/IV (80%; 89%), elevated LDH (55%; 48%), and extranodal involvement (67%; 59%). In refr pts, the ORR was 49%, which was generally consistent with the overall population (59%); although the sample size was limited, higher responses (ORR: 74%) were observed in rel pts. Additional clinical outcomes are reported (Table). The safety profile was consistent with the overall population. Grade 3 CRS occurred in one pt in each subgroup. Treatment-related ICANS-like events occurred in 2/45 pts (4%; refr) and 3/27 pts (11%; rel). Conclusions: Mosun-pola demonstrated durable benefits in ORR and CR rates irrespective of a poor response to 1L treatment. Outcomes for pts with refr or rel LBCL are encouraging. Clinical trial information: NCT03671018 . [Table: see text]

Subcutaneous epcoritamab (SC epcor) administered outpatient (outpt) for relapsed or refractory (R/R) diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL): Results from phase 2 EPCORE NHL-6.

7029 Background: Epcor is the only SC CD3xCD20 bispecific antibody approved for R/R DLBCL. In initial protocols, hospitalization after the 1st full dose of epcor was required to monitor patients (pts) for and characterize CRS. The EPCORE NHL-6 trial assessed whether R/R DLBCL/FL pts treated with SC epcor across US community and academic sites could be safely monitored in the outpt setting. Methods: Eligible pts had R/R DLBCL or FL and at least 2 prior lines of therapy. Epcor was given in 28-d cycles [C]; C1 SUD: 0.16 mg then 0.8 mg, followed by 48 mg; C1–3: QW; C4–9: Q2W; C≥10: Q4W. Pts received safety education, including early identification and reporting of symptoms of CRS and ICANS, and were required to stay ≤30 min of the site of care for 24 h after the 1st full dose. Based on C1 optimization (OPT) findings from EPCORE NHL-1 (Vose ASH 2023, Abs 1729), the trial was amended to implement C1 OPT with hydration and dexamethasone after enrollment of 34 pts. Results: At data cutoff, 36 pts (23 DLBCL, 13 FL) received ≥1 dose of epcor (median cycles, 3). 13 and 23 pts were from US academic and community sites, respectively. Median age was 65 y, 67% of pts had extranodal disease, and 39% had prior CAR T. Any grade CRS occurred in 47% of pts and were mostly low grade (G1, n=9; G2, n=7; G3, n=1). Median time to onset of CRS after 1st full dose was 23 h. No CRS events led to discontinuation; 11 pts (31%) were treated with tocilizumab, 8 (22%) with corticosteroids, and 5 (14%) with both. ICANS occurred in 8% (all G1-2) with a median time to onset of 20 days from C1D1, and all resolved. Of 31 pts receiving the 1st full dose, 3 pts (10%) received epcor in the inpatient (inpt) setting while admitted for AEs other than CRS (pain management, leg injury, UTI, n=1 each). The remaining 28 pts (90%) received epcor and were monitored in the outpt setting. 12 total pts had 13 CRS events after the 1st full dose with CRS starting in the outpt setting in 10 pts (G1, n=6; G2, n=4). 7/28 (25%) pts initially monitored as outpts were subsequently managed as inpt for CRS. All 12 pts had resolution of CRS with a median time to resolution of 45 h. Conclusions: Pts with R/R DLBCL and FL were successfully treated with SC epcor and monitored in the outpt setting across different types of sites. CRS events occurring in the outpt setting were appropriately managed, and the observed CRS incidence and severity was comparable to that of the pivotal EPCORE NHL-1 trial. These data suggest that SC epcor can be safely administered and pts monitored outpt, and then managed inpt as needed for CRS. Enrollment is ongoing, and a larger dataset with C1 OPT including hydration and dexamethasone, which are anticipated to further lower CRS incidence and severity, will be presented later. Clinical trial information: NCT05451810 . [Table: see text]

Estimating the health care costs associated with receipt of lisocabtagene maraleucel: Insights from adults with mantle cell lymphoma (TRANSCEND NHL 001).

7028 Background: Anti-CD19 CAR T cell therapy is a major advancement for treating R/R B-cell malignancies such as mantle cell lymphoma (MCL). While effective disease management with CAR T cell therapy is expected to reduce patients’ health care resource utilization (HCRU) over the long-term, few studies have examined the short-term impacts of this treatment on HCRU and associated health care costs. Here, we used data from the TRANSCEND NHL 001 (NCT02631044) clinical trial to estimate the HCRU-related costs incurred by patients with R/R MCL over the first 12 months after receipt of lisocabtagene maraleucel (liso-cel). Methods: A retrospective analysis of clinical trial data was conducted to calculate the frequency of HCRU (medications [excluding liso-cel], diagnostics, procedures, ICU and non-ICU hospitalizations) observed over the 12 months immediately after administration of liso-cel. Costs for each HCRU event were derived from public databases and literature, adjusted to 2023 United States (US) dollars, and used to estimate patient-level health care costs. Results: Of the patients treated (N = 88), 76.1% were male, 87.5% were White, and mean ± standard deviation (SD) age was 67.5 ± 9 years. All patients were treated in the US and completed a median (range) of 3 (1–11) prior lines of therapy before receiving liso-cel. Most patients (93.2%) received the recommended dose of 100 × 106 CAR+ T cells. The total mean ± SD per-patient cost (excluding liso-cel) was estimated at $138,413 ± $58,555 over 12 months. Facility use accounted for 77.7% of all costs, primarily owing to non-ICU hospitalizations (98.9%), which had a mean ± SD length of stay of 19.5 ± 16.7 days per eligible patient. Half of all health care costs were incurred within the first month of infusion (53.2%), with each subsequent month contributing a fraction (1.5%–6.3%) of total costs. A total of 13 out of 88 patients received their initial infusion in an outpatient setting and incurred 23% fewer costs compared with those who received their infusion in an inpatient setting ($110,050 vs $143,418), primarily as a function of reduced first-month facility use. Total costs for patients receiving liso-cel in outpatient settings were further reduced to $72,771 upon exclusion of 3 outliers. Conclusions: Non-ICU hospitalizations were the largest driver of liso-cel–related costs in this R/R MCL cohort of clinical trial participants. Most of the cost burden was incurred within 1 month of treatment, with dramatic reductions in HCRU and health care costs observed thereafter. Results suggest that treatment in the outpatient setting, even in part (eg, at initial infusion only), may confer substantial cost savings to the health care system.

Preliminary safety and efficacy of TQB2930, a HER2-targeted bispecific antibody in patients with advanced breast cancer: Results from a phase 1b study.

1026 Background: TQB2930 is a HER2-targeted bispecific antibody, binding to two distinct HER2 epitopes, the same domain as trastuzumab (ECD4) and pertuzumab (ECD2). This study aims to evaluate the safety and efficacy of TQB2930 for patients with advanced breast cancer after failure of standard therapy. Methods: This phase 1b, dose-escalation and expansion trial included patients preferred HER2-expressing or HER2-amplified breast cancer who had received standard therapy. In the dose-escalation phase, TQB2930 was given weekly (10mg/kg, QW), biweekly (20mg/kg, Q2W), or triweekly (30mg/kg, Q3W). After the dose-escalation phase, eligible patients were enrolled and dosed biweekly or triweekly in the expansion cohort. The primary endpoints were safety, maximum tolerated or maximum administered dose, and the secondary endpoints were immunogenicity, pharmacokinetics, and tumor response per RECIST v1.1. Results: As of Dec 20, 2023, 34 patients(pts) have received TQB2930 weekly (n=3), biweekly (n=16), and triweekly (n=15). All pts were female, the median age was 59. 22 pts had HER2 expression of ICH3+ or ICH2+ with FISH+, and the others had ICH2+ with FISH- or ICH1+. The median prior lines of therapies were 3 (range: 0-8), with one pt intolerance to first-line treatment enrolled, and the median prior lines of HER2-targeted therapies were 2 (range: 0-8). No dose-limited toxicity was observed. The main treatment-related adverse events (TRAEs) were infusion reaction, occult blood of urine, leukopenia, and neutropenia. 3 pts were reported grade≥3 TRAEs, including neutropenia, anemia, and hypokalemia. Of 31 response-evaluable pts, the objective response rate (ORR) was 25.8% with 8 partial responses (PRs) were observed (including 5 confirmed PRs and 3 PRs awaiting confirmation). The disease control rate was 80.6%. Moreover, 5 pts achieved PR at 30mg/kg (ORR 41.7%), including one with prior exposure to trastuzumab, pyrotinib, tucatinib, ARX788, and the other one prior to trastuzumab, pertuzumab, lapatinib, MRG002. The median progression-free survival for all pts was 5.5 months (95%CI 3.58-NE). Additionally, Pharmacokinetic analysis showed exposure (Cmax and AUC0-t) of TQB2930 increased linearly with doses within 10~30mg/kg. After dosing, the mean peak concentration reached at 2.5-4.3 h, and the elimination half-life of TQB2930 was 109-161 h. Conclusions: TQB2930 is well tolerated and has demonstrated promising single-agent anti-tumor activity in HER2-positive breast cancer who have failed standard anti-HER2 therapies, including multiple lines of prior HER2 targeted agents. These early signs of activity support the further exploration of combination therapy of TQB2930 and the study is ongoing. Clinical trial information: NCT06202261 .

Association between treatment (tx) response and PFS and OS in R/R chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL): A 12-month landmark (LM) meta-analysis.

7047 Background: Despite advances in tx for CLL/SLL, CRs are rarely observed after tx in the R/R setting, thus impacting long-term outcomes. We evaluated the association between response after tx and survival outcomes in patients (pt) with R/R CLL/SLL. Methods: Adults with R/R CLL/SLL and ≥ 1 prior line of therapy (LOT) from 6 clinical trials (initiated after 01/01/2012 and completed before 12/31/2022) were sourced from the Medidata Enterprise Data Store. Cox models adjusted for potential prognostic factors were used to assess pt-level associations between achieving and maintaining a CR or CR with incomplete bone marrow recovery (CRi) by 12 mo after start of tx (LM date) and PFS and OS. In separate LM analyses (LMA), associations between achieving and maintaining CR/CRi, PR/nodular PR (nPR) by LM, or non-CR/non-PR (ie, those not achieving or maintaining CR/CRi or PR/nPR or not evaluated by LM), and PFS and OS were assessed. Results: Of 1604 pts (CLL, 97.7%; SLL, 2.3%; age ≥ 65 y, 61.8%; male, 66.6%; ECOG PS 0–1/2, 93.2%/6.8%; median [IQR] follow-up, 3.4 y [2.2–4.1]; median [IQR] LOT, 2 [1–3]; study tx, BTKi [40.4%], BCL2i [40.1%], anti-CD20 mAb [12.5%], and PI3Ki [9.9%]), 15.1% and 61.7% achieved a best overall response of CR/CRi and PR/nPR, respectively (ORR, 76.8%); 6.8% of pts had no response recorded in follow-up. A total of 1178 pts without progression, death, or censoring before LM were included in PFS LMA. Median (95% CI) PFS from LM was 64.4 mo (61.7–not reached [NR]) for CR/CRi, 43.3 mo (38.8–54.7) for PR/nPR, and 23.9 mo (18.3–50.6) for non-CR/non-PR. Pts who achieved and maintained CR/CRi had significantly longer PFS versus both non-CR/CRi and PR/nPR pts, with adjusted HR of 0.62 ( P = 0.01) and 0.64 ( P = 0.02), respectively (Table). For OS LMA, 1404 pts without death or censoring before LM were included. Median (95% CI) OS from LM was NR for CR/CRi and PR/nPR groups and 62.9 mo (51.2–NR) for non-CR/non-PR. At 24 mo from LM, 90% (85%–95%) CR/CRi, 87% (84%–89%) PR/nPR, and 72% (67%–77%) non-CR/non-PR pts were still alive. CR/CRi pts or PR/nPR pts had significantly longer PFS and OS versus non-CR/non-PR pts. Conclusions: We demonstrated that achieving and maintaining CR/CRi by 12 mo after start of tx was associated with significantly improved PFS versus achieving and maintaining PR/nPR, which was also better than not achieving/maintaining any response. These findings support the potential utility of durable CR/CRi as an informative early endpoint for assessing the value of tx in pts with R/R CLL/SLL. Adjusted HR (95% CI) [Table: see text]

Preliminary antitumor activity of COM701 in combination with COM902 and pembrolizumab in patients with MSS-CRC and liver metastases.

3597 Background: There is a high unmet need for the treatment of patients [pts] with metastatic microsatellite stable colorectal cancer [MSS-CRC]. We reported encouraging preliminary antitumor activity with the combination of COM701 + nivolumab in patients with MSS-CRC and liver metastases [12/22(77%)], [ORR 2/17 (12%); disease control rate [DCR] 5/17 (29%)]1. COM701 is a novel, 1st-in-class immune checkpoint inhibitor [ICI] that binds to PVRIG, a DNAM-1 axis member, leading to activation of T and NK-cells; COM902 is an ICI of TIGIT. Pembrolizumab is an ICI of PD-1. We hypothesized that in pts with metastatic MSS-CRC, the triple combination by inhibiting the DNAM-1 axis would demonstrate antitumor activity with a favorable safety and tolerability profile. We present encouraging preliminary results. Methods: We enrolled 20 pts with metastatic MSS-CRC who all received COM701 15 mg/kg + COM902 3 mg/kg + pembrolizumab 200 mg all IV Q3W. Primary objectives were safety/tolerability, with secondary objective of antitumor activity of the combination. Key inclusion criteria: Age ≥ 18 yrs, measurable disease, MSS by IHC or genomic testing, ≤3 prior lines including fluroropyrimidines, irinotecan, and oxaliplatin. Key exclusion criteria: prior receipt of ICI including anti-PVRIG, anti-TIGIT. Investigator assessed responses were per RECIST v1.1, safety per CTCAE v5.0. Results: Median age 57.5yrs, 11/20 [F], 15/20 [75%] pts with liver metastases. Median of 3 prior lines of therapy. Objective response rate [ORR] 1/20 [5%] pts; 7 pts with SD. Disease control rate [CR + PR + SD] 8/20 [40%]. In pts with liver mets ORR 1/15 [7%], DCR 6/15 (40%); 6/8 [75%] pts with best response ≥SD had liver mets. Treatment related AEs were reported in 11/20 [55%] pts, the majority were ≤G2 7/20 [35%] with the most frequent TRAE of 4 pts each with ≤G2 fatigue, myalgia, 4/20 pts with G3 TRAE, there were no ≥G4 TRAEs. Strong peripheral IFNɣ induction was observed after treatment. Three pts [1 PR, 2 SD] are ongoing at the time of data cut. Conclusions: The data further supports the antitumor activity of the combination of COM701 + COM902 + pembrolizumab in pts with MSS-CRC and specifically in patients with liver metastases. Of note the data further reinforces the data previously disclosed in a similar pt population of 22 pts that received COM701 + nivolumab1. No new safety signals are reported. Additional clinical and translational data will be presented at the conference. Data cut 01/09/2024. Reference: 1. Rasco D, Dumbrava E, Sharma M, et al659 COM701 plus nivolumab demonstrates preliminary antitumor activity and immune modulation of tumor microenvironment in patients with metastatic MSS-CRC and liver metastases. Journal for ImmunoTherapy of Cancer 2022;10:doi: 10.1136/jitc-2022-SITC2022.0659. Clinical trial information: NCT04354246 .

Final analysis of the BIMES trial, a phase II single arm study assessing efficacy and safety of bintrafusp alfa in previously treated advanced malignant pleural mesothelioma (GECP 20/09).

8084 Background: Transforming growth factor β (TGF-β) is involved in tumor immune evasion and epithelial–mesenchymal transition (EMT). As TGF-β upregulation and EMT are associated with resistance to anti-PD1 therapy, we evaluated the efficacy of bintrafusp alfa, a bifunctional fusion protein targeting TGF-β and PD-L1, in malignant pleural mesothelioma (MPM). Methods: Patients with advanced MPM who were previously treated with platinum-based chemotherapy were enrolled and received bintrafusp alfa 1200mg/m2 every 2 weeks until progression or for a maximum of two years. The primary objective was to determine the progression-free survival (PFS) by modified RECIST v1.1. assessed by the investigators. The expected median PFS was 4.5 months. Secondary objectives were overall response rate, duration of response, overall survival (OS) and safety. Results: Between October 2021 to March 2023, 47 patients were enrolled. Mean age was 70 years (41-84) and 36 (78.3%) were males. Most patients had epithelioid histology (82.9%) and had received only 1 prior line of therapy (84.8%). With a median follow-up of 11.5 months, 43 patients had disease progression and 24 patients died. The median number of doses administered was 4 (1-21) and reasons for treatment discontinuation were disease progression (82.6%), toxicity (6.5%), investigator decision (4.4%) and death (6.5%) by tumor progression. The median PFS was 1.9 months (95% CI 1.7 – 5.4) and the 6 month-PFS rate was 15.9%. Disease control rate was 34.8% (95% CI 22.2-49.9) consisting of 2 patients with partial response and 13 patients with stable disease as best response. The median OS was 11.9 months (95% CI 4.4 – not reached) and 6, 12 and 18-month OS rate was 65.3%, 46.5% and 26.6%, respectively. No significant differences in OS and PFS were observed based on MPM histological subtype. Grade 3-4 treatment-related adverse events occurred in 16 (34%) patients, anemia being the most common (n = 5); skin toxicity (n = 3); colitis (n = 2); adrenal insufficiency, acute kidney injury, allergic reaction, lipase, and amylase increased (n = 1 each). Conclusions: Bintrafusp alfa did not reach the expected efficacy in patients with advanced malignant pleural mesothelioma previously treated with platinum-based chemotherapy. Clinical trial information: NCT05005429 .

Evaluation of elranatamab vs EPd, PVd, or Kd in patients with relapsed or refractory multiple myeloma and prior anti-CD38–directed therapy: MagnetisMM-32.

TPS7576 Background: Elranatamab (ELRA), a humanized B-cell maturation antigen (BCMA)-CD3 bispecific antibody, has shown efficacy and manageable safety as a monotherapy in patients with relapsed or refractory multiple myeloma (RRMM). This study will evaluate ELRA monotherapy vs elotuzumab-pomalidomide-dexamethasone (EPd), pomalidomide-bortezomib-dexamethasone (PVd), or carfilzomib-dexamethasone (Kd) in patients with RRMM to determine whether ELRA can provide superior clinical benefit. Methods: MagnetisMM-32, a phase 3, open-label, multicenter, randomized study, will enroll ≈492 patients. Patients will receive ELRA (Arm A) or investigator’s choice of EPd, PVd or Kd (Arm B), until disease progression, unacceptable toxicity, withdrawal of consent, loss to follow-up, or study termination. Patients treated with ELRA will receive 2 step-up priming doses followed by weekly doses in a 28-day cycle. Patients who achieve a PR or better for ≥2 months will be eligible for reduced dosing frequency. Patients will be randomized 1:1 (stratified by prior line of therapy [1 vs 2 vs 3/4] and International Staging System disease stage [1/2 vs 3]). Key inclusion criteria include age of ≥18 years, prior multiple myeloma diagnosis with measurable disease (per IMWG criteria), evidence of progressive disease or failure to achieve a response to last line of multiple myeloma therapy, 1 to 4 prior lines of therapy including an anti–CD38 antibody–containing regimen (for ≥2 consecutive cycles) and a lenalidomide-containing regimen (for ≥2 consecutive cycles), adequate bone marrow function, and an ECOG performance status of ≤2. Key exclusion criteria include stem cell transplant ≤12 weeks prior to enrollment; active, uncontrolled infection; prior BCMA-directed or CD3-redirecting therapy; and unable to receive EPd, PVd, or Kd. The primary and key secondary endpoints are progression-free survival (PFS) by blinded independent central review (BICR) per IMWG criteria and overall survival (OS), respectively. Other secondary endpoints include PFS by investigator, objective response rate, duration of response, time to response by BICR, PFS on next line of therapy per IMWG criteria, MRD negativity rate, safety, pharmacokinetics of ELRA, immunogenicity, and health-related quality of life outcomes. The primary endpoint and OS will be compared statistically between treatment arms by stratified log-rank tests. Clinical trial information: NCT06152575 .

Effect of UNO101 on tumor microenvironment in relapsed or refractory, unresectable, primary, or metastatic cutaneous and subcutaneous malignancies.

e14575 Background: Nitric oxide (NO) is a ubiquitous, endogenously generated gas implicated in the homeostatic regulation of physiological processes, and NO is implicated in numerous pathological conditions. Preclinical studies evaluating the effect of high concentration exogenously administered NO demonstrated anti-cancer properties and suggested that it may serve as a potent tumoricidal agent. We have previously shown that treating mouse colon carcinoma (CT26) tumor-bearing mice with ultra-high concentrations of nitric oxide (UNO) upregulates innate and adaptive immune cells locally and systemically. Methods: Upon a signed written ICF, a single UNO101 dose of 25,000 parts per million (ppm), administered intratumorally over 5 minutes, was evaluated in relapsed or refractory, unresectable, primary, or metastatic cutaneous and subcutaneous malignancies. Subjects with an ECOG PS of 0–3, at least 3 months of life expectancy and tumor size of 4.5 mm minimum and 30 mm maximum length were eligible for enrollment. RECIST v1.1 and clinical physical examination by PI assessment was utilized to assess the rate of malignant tumor response. Toxicity was graded per NCI CTCAE v5.0. Results: In this first-in-human Phase 1 clinical trial, six subjects, 4F/2M were enrolled with a median age of 61.5 years, (range, 34–81) and ECOG PS reported as 0 or 1. Tumor types enrolled included breast (n=3), melanoma (n=1), and squamous cell carcinoma (n=2) with a median of 4 prior lines of therapy (range, 2–11) and a median of 4.7 years (range, 1.4–9.5) since time of diagnosis to study entry. One related SAE (not dose limiting) of hypoxia, Grade 4, was reported, which resulted in cessation of UNO101 treatment after 1:55 minutes. The other five administrations were completed successfully, with no further SAEs. Other reported drug related AEs were primarily Grade 1 that resolved/recovered without sequelae. Clinical immune blood biomarkers post UNO101 treatment demonstrated modulation of the tumor microenvironment by upregulating of cytotoxic T-cells (11.1%), T-central memory cells (190.6%) as a percent of total T-cells, and dendritic cells (231.4%) as a percentage of WBCs, from baseline to Day 21. Further, T-regulatory cells (38.0%) were downregulated as a percentage of total T-cells from baseline to Day 21. Based on available physical examination and caliper measurements, clinical presentation on Day 7 on two subjects, significant clinical responses were observed. Conclusions: To date,a single dose of UNO101 at 25,000 ppm is well tolerated, with biomarkers suggesting immune action within the tumor microenvironment, trending in a favorable direction on Day 21 in a heavily pre-treated population. Additional UNO101 single dose of 50,000 ppm, and possibly 100,000 ppm, will be further evaluated for safety/tolerability, impact on immune biomarkers, and preliminary efficacy. Clinical trial information: NCT05351502 .

Long-term survival outcomes in patients with relapsed/refractory large B-cell lymphoma after treatment of relma-cel: 4-year follow-up in RELIANCE study.

e19001 Background: RELIANCE study (NCT04089215) demonstrated the efficacy and safety of relma-cel, a CD19-targeted chimeric antigen receptor T-cell product, in patients with heavily pre-treated relapsed/refractory large B-cell lymphoma (r/r LBCL). We previously reported efficacy of relma-cel, noting objective response rate (ORR) in 77.59% of patients (CRR 53.45%), 2-year progression-free survival (PFS) rate and overall survival (OS) rate were 38.8% and 69.3%, respectively. Herein, we aimed to update the long-term survival results for 4-year follow-up (FU). Methods: Study design was previously published. Eligible patients were adults with histologically confirmed r/r LBCL and had failed at least two prior lines of therapy, including an anti-CD20 monoclonal antibody and an anthracycline-based regimen. Patients were enrolled at 10 clinical sites in China and underwent lymphodepletion prior to receiving relma-cel at a single dose of 100 × 106 (n=27) or 150 × 106 (n=32) CAR+ T cells. The primary endpoint was ORR at 3-month, as assessed by investigators. Secondary endpoints were duration of response (DOR), PFS, OS and safety profiles. For this abstract, we collected the survival status and updated the survival outcomes. Results: From Nov 2017 to Dec 2019, a total of 68 patients were enrolled, and 59 received relma-cel infusion. Among 58 evaluable efficacy patients with 2-year FU, 31 achieved CR (CR group), 14 achieved PR (PR group) and 13 had no response (Non-responder group). As of Dec 18, 2023, with 48.1 months (95% CI, 37.75 to 49.38) of median FU, 25 patients were still alive, 18 were died (5 deaths in CR group, 5 in PR group and 8 in Non-responder group), and 15 patients were censored due to lost to FU including 7 lost within 2 years and 8 after 2 years. The median OS were not reached (NR), and 1-year and 2-year OS rate were reported previously. The update estimated landmark OS rates were 69.3% at 3-year and 66.7% at 4-year. The OS rates of CR group at each year were numerically higher than those of PR group and Non-responder group (87.1% v.s. 59.3% v.s. 30.8% at 3-year and 82.5% v.s. 59.3% v.s. 30.8% at 4-year; Table). Conclusions: Four-year FU results in RELIANCE Study suggested that, although heavily pretreated, the patients who had response, especially who achieved CR, may experience greater survival benefits, from relma-cel therapy. Clinical trial information: NCT04089215 . [Table: see text]

Real-world barriers to CAR-T access: A Canadian referral center perspective.

e19002 Background: CD19 chimeric antigen receptor T-cell (CAR-T) is the standard of care for patients with relapsed or refractory large B-cell lymphoma (LBCL) beyond second line therapy. Access to CAR-T remains a significant barrier for patients and is limited by the numbers of CAR-T centers, patient comorbidities and lymphoma kinetics. This study aims to define clinical features associated with CAR-T ineligibility and associated outcomes in a real-world setting. Methods: We conducted a single center retrospective study of all adult patients with R/R LBCL referred at Hôpital Maisonneuve-Rosemont in Montreal, Canada, for CAR-T between July 2019 and December 2023. Comprehensive data were gathered from electronic medical records. This study was approved by the institutional ethics committee. Results: A total of 235 patients were evaluated: 133 (57%) were infused, 10 (4%) were apheresed but not infused and 92 (39%) patients were deemed ineligible and further analyzed. The main reasons for ineligibility were ECOG performance score more than 1 (n=23), comorbidities (n=18), not R/R to two prior lines of therapy (LOT) (n=15) and rapid disease progression (n=15). Prohibitive comorbidities included: creatinine clearance <45ml/min (n=13), left ventricular ejection fraction <45% (n=2), unstable coronary artery disease (n=1), severe valvular disease (n=1) and Child B cirrhosis (n=1). 10 declined CAR-T and 10 were diagnosed or had lymphoma subtypes not covered by CAR-T reimbursement criteria: grade 3B follicular lymphoma (n=5), T-cell lymphoma (n=2), Hodgkin lymphoma (n=1), Richter from chronic lymphocytic leukemia (n=1) and transformed marginal zone lymphoma (n=1). 33 had more than one exclusion criteria. Median age at referral was 66 years (range: 25-87). Median IPI at diagnosis (available in 74%) was 3 (range: 0-5). At CAR-T evaluation, 77 patients had a stage 3 or 4 disease and 7 had CNS involvement. Median LOT for LBCL were 2 (range: 0-5), 46 were primary refractory and 23 relapsed within 12 months. 18 patients had undergone prior high dose therapy and autologous stem cell transplant (HDT-ASCT). 6 were exposed to novel therapies (polatuzumab=6, mosunetuzumab=2). Median follow-up after CAR-T exclusion was 4.25 months (range: 0-49.2). 50 (68% of patients with B-cell lymphoma R/R to at least 2 LOT) were deceased at time of analysis. Data on further LOT was available for 22 patients: 10 received novel therapies (tafasitamab=5, polatuzumab=3, mosunetuzumab=1, alectinib=1), 6 HDT-ASCT, 3 allogeneic stem cell transplant, 4 conventional chemotherapies and 2 radiation therapy. Conclusions: 39% of evaluated patients with R/R LBCL were ineligible for CAR-T mainly due to poor performance status, comorbidities and prohibitive progressive disease. Our study did not capture patients not referred due to geographical considerations but highlights dismal outcomes for patients ineligible for CAR-T. Widespread access to novel therapies is awaited.