12-mo OS Rates Research Articles

J-TAIL-2: A prospective, observational study of atezolizumab (atezo) combined with carboplatin and etoposide (CE) in patients (pts) with extensive-stage small cell lung cancer (ES-SCLC) in Japan.

8092 Background: Atezo + CE is approved for the first-line treatment of ES-SCLC based on IMpower133 (IMp133; NCT02763579). Due to the limited data available in Japanese pts, J-TAIL-2 (NCT04501497) is evaluating the efficacy and safety of atezo + CE in Japanese pts in the clinical setting. Methods: Pts from Japan had ES-SCLC, were aged ≥20 y and were scheduled to start atezo + CE in clinical practice. The primary endpoint was 12-mo OS rate. Secondary endpoints included OS, PFS and safety. Efficacy and safety were evaluated in these subgroups: IMp133-unlike (e.g., ECOG PS 2-4, CNS metastases, history/complication of autoimmune or interstitial lung disease, previous treatment for ES-SCLC) vs IMp133-like (met IMp133 eligibility criteria), age <70 vs ≥70 y and geriatric score (G8) < median vs ≥ median. G8 was assessed in pts aged ≥70 y at baseline, with lower vs higher scores indicating poorer health status. Results: From Aug 21, 2020, to data cutoff (Feb 3, 2023), 403 pts were enrolled from 150 sites. Baseline characteristics are shown in the Table. In the efficacy analysis population (n=399), the 12-mo OS rate was 63.7% (95% CI: 58.6, 68.3), median OS (mOS) was 16.5 mo and mPFS was 5.1 mo. In the IMp133-unlike vs -like groups, mOS was 15.5 vs 19.1 mo (HR, 1.32; 95% CI: 0.98, 1.77) and mPFS was 4.8 vs 5.4 mo (HR, 1.14; 95% CI: 0.90, 1.45). In pts aged <70 vs ≥70 y, mOS was 17.9 vs 16.4 mo (HR, 1.18; 95% CI: 0.90, 1.55) and PFS was 5.1 vs 5.1 mo (HR, 1.07; 95% CI: 0.86, 1.33). The median G8 score was 12; in pts with a G8 score < median vs ≥ median, mOS was 11.1 vs 18.4 mo (HR, 1.95; 95% CI: 1.38, 2.77) and mPFS was 4.8 vs 5.2 mo (HR, 1.25; 95% CI: 0.94, 1.67). In the safety analysis population (n=400), treatment-related AEs occurred in 36.0% of pts, Grade (Gr) ≥3 AEs in 66.3% and Gr 5 AEs in 2.8%. Safety outcomes were similar for the IMp133-unlike vs -like and age <70 vs ≥70 y groups. In pts with a G8 score < median vs ≥ median, Gr ≥3 AEs occurred in 70.8% vs 63.5% of pts and Gr 5 AEs occurred in 5.2% vs 0.8% of pts. Conclusions: The efficacy and safety of atezo + CE in Japanese pts treated in clinical practice were consistent with those seen in IMp133. Subgroup analyses support the use of atezo + CE in pts who would have been ineligible for IMp133, although clinical outcomes favored the IMp133-like group. Efficacy and safety were similar for pts aged <70 vs ≥70 y but were worse for those with lower vs higher G8 scores, suggesting that this assessment may be a useful tool for therapeutic strategies. These data support the use of atezo + CE in Japanese pts with ES-SCLC, including in subgroups excluded from IMp133. Clinical trial information: NCT04501497 . [Table: see text]

J-TAIL-2: A prospective observational study of atezolizumab (atezo) combination therapy in patients (pts) with non-small cell lung cancer (NSCLC) in Japan.

8573 Background: The IMpower130 (West et al. Lancet Oncol 2018), IMpower132 (Nishio et al. JTO 2021) and IMpower150 (1) trials led to the approval of first-line atezo combination therapies for NSCLC. As data remain limited in Japanese pts, J-TAIL-2 (NCT04501497) is evaluating the efficacy and safety of 3 atezo combination therapies for NSCLC in the clinical setting in Japan. Methods: Japanese pts had unresectable advanced or recurrent NSCLC, were ≥20 y old, and were scheduled to start atezo combination therapy in clinical practice. Pts received atezo + carboplatin and nab-paclitaxel (atezo + CnP), atezo + carboplatin or cisplatin + pemetrexed (atezo + PP) or atezo + bevacizumab + carboplatin + paclitaxel (atezo + bev + CP). The primary endpoint was 12-mo OS rate. Secondary endpoints included OS and safety. Efficacy and safety were analyzed in the IMpower-unlike (did not meet the main eligibility criteria of each IMpower study) and IMpower-like subgroups. Geriatric assessment (G8) was done in pts ≥70 y old at baseline; a score < median vs ≥ median indicated poorer health status. Results: From Aug 21, 2020, to data cut off (Feb 3, 2023), 814 pts were enrolled at 150 sites (atezo + CnP, n=217; atezo + PP, n=211; atezo + bev + CP, n=386). Baseline characteristics in the efficacy analysis population (n=791) are shown (Table). The IMpower-unlike group included pts with ECOG PS ≥2, brain metastases or interstitial lung disease. Twelve-mo OS rates (95% CI) were 62.9% (55.8, 69.2), 72.1% (65.2, 77.9) and 68.3% (63.2, 72.9), and median OS was 19.7, 23.5 and 17.3 mo with atezo + CnP, atezo + PP and atezo + bev + CP, respectively. OS HRs (95% CI) in the IMpower-unlike vs -like subgroups were 1.36 (0.91, 2.05), 1.08 (0.70, 1.68) and 1.49 (1.09, 2.06), respectively. The median G8 score for all evaluable pts was 13; in pts with a G8 score < median vs ≥ median, OS HRs (95% CI) were 2.10 (1.22, 3.61), 3.53 (1.95, 6.37) and 2.04 (1.22, 3.40) with atezo + CnP, atezo + PP and atezo + bev + CP, respectively. In the safety analysis population (n=800), Grade ≥3 AEs occurred in 60.4% of pts and Grade 5 AEs in 1.3%. Conclusions: In Japanese pts, the efficacy and safety of each atezo combination therapy were comparable to those seen in the relevant IMpower studies and largely consistent in pts who would have been ineligible for the trials. Pts aged ≥70 y with a G8 score < median vs ≥ median had poorer efficacy and safety outcomes. 1. Socinski et al. NEJM 2018. Clinical trial information: NCT04501497 . [Table: see text]

Belzutifan plus lenvatinib (len) for Chinese patients (pts) with previously treated advanced clear cell renal cell carcinoma (ccRCC): Preliminary results of cohort 1 of the phase 1 LITESPARK-010 study.

4537 Background: Belzutifan, a first-in-class HIF-2α inhibitor, alone or in combination with a VEGFR-TKI, has shown durable antitumor activity in first- and subsequent-line settings of advanced ccRCC. LITESPARK-010 (NCT05030506) is a phase 1, 2-cohort, open-label study of belzutifan + len, with or without pembrolizumab, in Chinese pts with advanced ccRCC. We present preliminary results cohort 1. Methods: Chinese adults with histologically confirmed ccRCC who had 1-3 prior treatment regimens received belzutifan 120 mg PO QD for 3 wk followed by belzutifan 120 mg + len 20 mg PO QD until intolerable toxicity, disease progression, or pt withdrawal. The study included a dose-limiting toxicity (DLT) phase of 21 days after the start of combination treatment. Dual primary end points were safety and PK. Secondary end points included ORR, DOR, and PFS per RECIST v1.1 by investigator assessment and OS. Results: As of August 29, 2023, 24 pts were enrolled in cohort 1 and 23 received combination treatment; 1 pt discontinued in the monotherapy period because of treatment with non-study anti-cancer therapy. Median age was 61 years, 17 pts (71%) were male, and 14 (58%) had intermediate/poor IMDC risk. 14 pts (58%) received 1 prior line of therapy and 10 (42%) received ≥2 prior lines. Five pts (21%) received prior therapy with a PD-(L)1 inhibitor. As of the data cutoff date, 11 pts (46%) remained on treatment. Median follow up was 14.4 mo (range, 1.6-22.1). Ten pts were evaluated in the DLT phase, and 1 experienced a DLT (grade 2 treatment-related transient ischemic attack). All 24 pts (100%) experienced a treatment-related AE (TRAE) of any grade, most commonly anemia (100%) and proteinuria (88%). Grade 3 or 4 TRAEs occurred in 17 pts (71%), most commonly anemia (29%) and hypertension (29%). One pt (4%) experienced grade 3 hypoxia. No pts died (grade 5) due to a TRAE. After a single dose of belzutifan monotherapy, median Tmax was 1.8 h (range, 0.6-8.0), geometric mean AUC0-24 was 22,400 h·ng/mL (90% CI, 19,600-25,500), and geometric mean Cmax was 1640 ng/mL (90% CI, 1490-1820). Steady-state concentration was reached after 14 days of belzutifan monotherapy treatment; the accumulation ratio of AUC0-24 was 1.7 (90% CI, 1.5-1.9). Belzutifan + len treatment had similar PK to belzutifan monotherapy. In all 24 pts, confirmed ORR was 50% (95% CI, 29-71; all PRs). Median DOR was not reached (NR; range, 3.5-20.4+ months); 50% of responders remained in response for ≥12 mo per Kaplan-Meir estimate. Median PFS was 13.7 mo (95% CI, 8-NR) and median OS was NR (95% CI, NR-NR). The 12-mo PFS and OS rates were 57% and 75%, respectively. Conclusions: Preliminary data from the belzutifan + len showed promising antitumor activity in Chinese pts with previously treated ccRCC. The safety of belzutifan 120 mg + len 20 mg was consistent with the safety profiles of the individual drugs. Clinical trial information: NCT05030506 .

Ciltacabtagene autoleucel in patients with lenalidomide-refractory multiple myeloma: CARTITUDE-2 cohort A expansion subgroup.

7535 Background: The phase 2 multicohort CARTITUDE-2 study is evaluating ciltacabtagene autoleucel (cilta-cel) in patients (pts) with MM across multiple settings. Cohort A is examining cilta-cel in earlier lines of treatment (tx; LOT) in pts with lenalidomide (len)-refractory multiple myeloma (MM). Initial results for cohort A (N=20; median follow-up, 30 mo) showed cilta-cel led to minimal residual disease negativity (MRD neg) at 10–5 in 100% of pts with evaluable samples (n=17). ORR was 95% (19/20), median DOR was not reached (NR), and the 24-mo PFS rate was 75%. We report protocol-specified results for the expansion subgroup. Methods: Pts with len-refractory MM after 1–3 LOT, including a PI and IMiD, and no anti-BCMA tx were enrolled. A single cilta-cel infusion (target dose, 0.75×106 [range, 0.5–1.0×106] CAR+ viable T cells/kg) was given 5–7 d after the start of lymphodepletion. Cohort A initially evaluated cilta-cel manufactured by clinical trial processes and later expanded to evaluate cilta-cel manufactured by commercial processes. Primary endpoint was MRD neg at 10–5. Efficacy is reported for pts who received cilta-cel at target dose; demographics, baseline disease characteristics, and safety are reported for all treated pts in the expansion subgroup. Results: As of Sept 5, 2023, median follow-up was 16 mo. Of 24 pts enrolled, 23 received cilta-cel infusion (22 at target dose). Median age was 63 y, 52% were male, and 61% were triple-class exposed. Of 16 MRD-evaluable pts, 100% achieved MRD neg at 10–5; median time to MRD neg was 2 mo (range, 1–12). ORR was 91% (20/22). Median DOR was NR; 79% of responders remained in response at 12 mo. Median (range) time to first and best responses were 1 mo (1–10) and 6 mo (1–19), respectively. 12-mo PFS and OS rates were 77% and 91%, respectively. All pts had TEAEs (grade [gr] 3/4, n=22; gr 5, n=1). Hematologic TEAEs included neutropenia (96%), leukopenia (65%), lymphopenia (65%), anemia (57%), and thrombocytopenia (57%). Infections occurred in 8 (35%) pts (gr 3/4, n=1; gr 5, n=1 due to sepsis). CRS occurred in 23 (100%) pts (gr 1/2, n=23); median time to onset was 8 d and recovery was 4 d. ICANS occurred in 4 (17%) pts (gr 1, n=3; gr 4, n=1); median time to onset was 10 d and recovery was 2 d. No other neurotoxicities or MNTs/parkinsonism occurred. 2 pts had secondary malignancies (SM); 1 pt had separate SM of gr 2 basal cell carcinoma and gr 2 squamous cell carcinoma and 1 pt had MDS diagnosed on d 846 that later transformed to AML. Per investigator assessment, SM were not tx-related. Conclusions: In the expansion subgroup of cohort A, cilta-cel led to deep and durable responses in pts with len-refractory MM as early as after first relapse; safety was consistent with the known mechanism of action of CAR-T tx. Results in the expansion and initial subgroups are comparable. Data for CARTITUDE-2 cohort A underscore observations in CARTITUDE-4 which enrolled a similar pt population. Clinical trial information: NCT04133636 .

Phase 1 study of anti–immunoglobulin-like transcript 3 (ILT3) monoclonal antibody MK-0482 + pembrolizumab + gemcitabine + nab-paclitaxel (Gem/Nab-P) in patients (pts) with metastatic pancreatic ductal adenocarcinoma (mPDAC).

4139 Background: Standard first-line treatment of mPDAC includes Gem/Nab-P doublet therapy, which typically results in an ORR of 23%-35%, a median PFS of 5-6 mo, and a median OS of 7-10 mo. ILT3 is an inhibitory receptor expressed on monocytic myeloid cells, including tolerogenic dendritic cells and myeloid-derived suppressor cells. MK-0482 is a novel humanized IgG4 monoclonal antibody targeting ILT3. ILT3 inhibition with MK-0482 has the potential to relieve immunosuppression within the tumor microenvironment. In the expansion cohort of the first-in-human phase 1 study MK-0482-001 (NCT03918278), the combination of MK-0482 + pembrolizumab + Gem/Nab-P was evaluated in pts with treatment-naive mPDAC. The safety and efficacy data from this cohort are presented. Methods: Pts aged ≥18 y with previously untreated mPDAC, measurable disease per RECIST v1.1, and an ECOG PS of 0 or 1 received MK-0482 750 mg Q3W + pembrolizumab 200 mg Q3W IV for ≤35 cycles + Gem/Nab-P (gemcitabine 1000 mg/m2; nab-paclitaxel 125 mg/m2) on days 1, 8, and 15 Q4W until PD or treatment discontinuation. The primary end point was safety. Secondary end points were ORR, DCR (CR + PR + SD), and DOR by investigator assessment per RECIST v1.1. Exploratory end points included PFS per RECIST v1.1 and OS. Results: A total of 37 pts were enrolled and received study treatment. At data cutoff (Oct 3, 2023), median follow-up was 13 mo (range 8.9-18.9). Median age was 65 y (range, 39-77). Most pts were male (54%), had an ECOG PS 1 (65%), and had ≥3 sites of metastasis (54%). Any-cause adverse events (AEs) occurred in all pts and treatment-related AEs (TRAEs) occurred in 36 pts (97%). Grade 3 or 4 TRAEs occurred in 27 pts (73%); the most frequent (≥10%) were decreased neutrophil count (27%), anemia (19%), and neutropenia (19%). No deaths due to TRAEs occurred. Immune-mediated AEs occurred in 12 pts (32%); the most frequent (≥10%) was hypothyroidism (11%). Grade 3 immune-mediated AEs occurred in 5 pts (14%; hepatitis, n = 2; severe skin reactions, n = 2; colitis, n = 1); no grade 4 or 5 events occurred. Confirmed ORR was 43% (16/37; 95% CI, 27.1-60.5), DCR was 84% (31/37; 68.0-93.8), and median DOR was 8.5 mo (range, 3.7-17.8+). Median PFS was 8.5 mo (95% CI, 5.7-12.3) and median OS was 15.6 mo (10.5-22.1); 12-mo PFS and OS rates were 35% and 60%, respectively. Biomarker data will be included in the presentation. Conclusions: MK-0482 + pembrolizumab + Gem/Nab-P showed a manageable AE profile in patients with treatment-naive mPDAC, which was generally consistent with the combined safety profiles of pembrolizumab-based immunotherapy and Gem/Nab-P, respectively. The 4-drug combination showed increased clinical efficacy compared with that historically observed for chemotherapy regimens. Further evaluation is needed to confirm the clinical activities observed. Clinical trial information: NCT03918278 .

Phase 1 study of anti–immunoglobulin-like transcript 3 (ILT3) monoclonal antibody (mAb) MK-0482 + pembrolizumab (pembro) in patients with recurrent inoperable glioblastoma (GBM).

2046 Background: For patients with GBM, treatment options are limited once the disease has recurred and become inoperable after standard first-line therapy. ILT3 is an inhibitory receptor expressed on monocytic myeloid cells, including tolerogenic dendritic cells and myeloid-derived suppressor cells (MDSCs). High expression of ILT3 on these immune cells has been associated with immune tolerance and suppression of T-cell function. Data have shown that GBMs have high ILT3 expression and high levels of MDSCs within the tumor microenvironment (TME). MK-0482 is a novel humanized IgG4 mAb targeting ILT3. Inhibition of ILT3 with MK-0482 may help relieve immunosuppression and improve T-cell function within the TME. In the expansion cohort of the first-in-human phase 1 study (MK-0482-001; NCT03918278), MK-0482 was evaluated in combination with pembro in a cohort of patients with recurrent inoperable GBM. The safety and efficacy data from this cohort are presented herein. Methods: Patients aged ≥18 y with their first recurrent inoperable GBM and a Karnofsky performance status (KPS) ≥80 were enrolled. Patients received MK-0482 750 mg Q3W + pembro 200 mg Q3W IV for up to a maximum of 35 cycles. The primary objective was to determine safety and tolerability of MK-0482 + pembro. Secondary objectives were to evaluate ORR, DCR (CR + PR + SD), and DOR by investigator assessment per Response Assessment in Neuro-Oncology (RANO). Exploratory objectives included evaluation of PFS per RANO and OS. Results: Overall, 25 patients were enrolled and received study treatment. At data cutoff (October 3, 2023), median follow-up duration was 9.3 mo (range, 5.6-14.5); treatment was ongoing in 1 patient. Median age was 56 y (range, 33-76). Most patients were male (72%), had a KPS of 80 (68%), and had IDH1 wild-type tumors (88%). All patients had previously received systemic therapy: 24 of 25 (96%) received prior temozolomide and 3 of 25 (12%) received prior glasdegib. Overall, 22 patients (88%) had an adverse event (AE); 10 patients (40%) had treatment-related AEs, most commonly (≥10%) arthralgia (12%), fatigue (12%), and increased ALT (12%). Grade 3 treatment-related AEs occurred in 2 patients (8%; increased ALT [n = 1] and fatigue [n = 1]). No grade 4 or 5 treatment-related AEs occurred. Four patients (16%) experienced immune-mediated AEs (hypothyroidism, n = 2; hepatitis, n = 1; pancreatitis, n = 1); all were grade 1 or 2. Confirmed ORR was 12% (3/25; 95% CI, 2.5-31.2), DCR was 32% (8/25; 14.9-53.5), and median DOR was 11.1 mo (range, 9.9-16.6+). Median PFS was 1.4 mo (95% CI, 1.3-2.9) and median OS was 9.3 mo (6.3-13.7); 6-/12-mo PFS and OS rates were 24%/16% and 72%/36%, respectively. Biomarker data will be included in the presentation. Conclusions: MK-0482 + pembro had a manageable AE profile with modest antitumor activity in patients with recurrent inoperable GBM. Clinical trial information: NCT03918278 .

Abstract CT038: Preliminary efficacy and safety results of anti-TROP2 ADC SKB264 (MK-2870) in patients (pts) with previously treated advanced gastric (G) or gastroesophageal junction (GEJ) cancer from a Phase 2 study

Abstract Background: Overexpression of TROP2 (trophoblast cell surface antigen 2) in advanced gastric cancer is known as a poor prognostic factor. SKB264 (MK-2870) is a TROP2 ADC developed with a novel linker to conjugate the payload, a belotecan-derivative topoisomerase I inhibitor. The linker is affected by both extracellular pH-sensitive cleavage and intracellular enzymatic cleavage within tumor cells, which leads to efficiently release payload inside tumor cells as well as within tumor microenvironment to exert its anti-tumor effects. Here, we report the preliminary results from a Phase 2 expansion cohort in pts with advanced G/GEJ cancer. Methods: Pts with previously treated inoperable advanced G/GEJ adenocarcinoma were enrolled to receive SKB264 monotherapy at 5 mg/kg Q2W until disease progression or unacceptable toxicity in Phase 2 expansion cohort of KL264-01 study (NCT04152499). Pts with heavily pre-treated G/GEJ cancer were enrolled first, and then the cohort was amended to enroll pts with only one prior therapy of chemotherapy and anti-PD-1/L1 therapy. Tumor assessment was performed every 8 weeks per RECIST v1.1 assessed by investigator. Results: At data cutoff date (Nov 22, 2023), a total of 48 pts were enrolled and followed up for at least 9 weeks. 24 pts (50.0%) had received one prior line of therapy (2L), while 24 pts (50.0%) had received ≥ 2 prior lines of therapy (3L+). 40 pts (83.3%) had received prior anti-PD-1/L1 inhibitors. Treatment-related adverse events (TRAEs) of ≥ Grade 3 were reported in 52.1% of pts. The most common ≥ Grade 3 TRAEs (occurred in ≥5% of pts) were anemia (20.8%), neutrophil count decreased (18.8%), WBC decreased (12.5%) and neutropenia (6.3%). TRAEs leading to dose reduction and dose delay occurred in 18.8% and 33.3% of pts, respectively. No TRAEs leading to treatment discontinuation or deaths occurred. No neuropathy or drug-related ILD/pneumonitis was reported. Of 41 response-evaluable pts (defined as ≥ 1 on-study scans), the ORR was 22.0% (9 PRs, 2 pending confirmation) and disease control rate (DCR) was 80.5%. The ORRs in the 2L and 3L+ setting were 27.3% (including 2 pending confirmation) and 15.8%, respectively. Median duration of response (DoR) was 7.5 months (mos). In the subset of 3L+ pts (n=24 including 54.2% of pts with ≥ 4 prior lines of therapy) with more mature follow-up (median follow up of 14.6 mos), median progression free survival (mPFS) was 3.7 mos (95% Cl: 2.6, 5.4); median overall survival (mOS) was 7.6 mos (95% Cl: 5.3, 15.5) with 12-mo OS rate of 32.6%. Conclusions: The preliminary data suggests that pts with heavily pre-treated advanced G/GEJ cancer could achieve durable response and potentially prolonged OS from SKB264 monotherapy, with a manageable safety profile. A Phase 3 global study of SKB264 monotherapy vs SOC in 3L+ G/GEJ adenocarcinoma is being planned. Citation Format: Jordi Rodon, Zev A. Wainberg, Mingjun Zhang, Tianshu Liu, Bo Liu, Guohua Yu, Yongmei Yin, Shuang Zhang, Yanjun Mi, Xingya Li, Xian Wang, Yunpeng Liu, Xiang Wang, Ying Cheng, Xiaoqing Zhang, Yalan Yang, Junyou Ge, Omobolaji O. Akala, Elliot Chartash, Jin Li. Preliminary efficacy and safety results of anti-TROP2 ADC SKB264 (MK-2870) in patients (pts) with previously treated advanced gastric (G) or gastroesophageal junction (GEJ) cancer from a Phase 2 study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT038.

Coformulated quavonlimab and pembrolizumab (pembro) in combination with lenvatinib (lenva) as first-line (1L) therapy for patients (pts) with advanced hepatocellular carcinoma (HCC): Phase 2 KEYSTEP-004 study.

484 Background: Combinations of a PD-1/L1 inhibitor with a CTLA-4 or VEGF inhibitor have been approved as 1L treatment options for pts with advanced HCC. The multicenter, phase 2 KEYSTEP-004 study (NCT04740307) was conducted to evaluate the coformulation of quavonlimab (CTLA-4 inhibitor) and pembro (PD-1 inhibitor) in combination with lenva (multi–tyrosine kinase inhibitor) as 1L treatment for pts with advanced HCC. Methods: Pts were ≥18 y of age, had histologically or radiographically confirmed HCC with no prior systemic therapy, and were not amenable to curative therapy; had Child-Pugh class A; and ECOG PS 0 or 1. The study consisted of a safety lead-in phase (approximately 6-20 pts) to evaluate the tolerability of the recommended phase 2 dose of lenva with a possibility of dose modification based on dose-limiting toxicities (DLTs) and an efficacy expansion phase (approximately 110 pts). In the safety lead-in phase, pts received a fixed-dose coformulation of quavonlimab 25 mg and pembro 400 mg IV Q6W in combination with lenva 8 mg (body weight [BW] <60 kg) or 12 mg (BW ≥60 kg) PO QD. Allocation to the efficacy expansion phase was allowed if the doses of lenva were determined to be tolerable. Primary end points were ORR per RECIST v1.1 by BICR and safety. Secondary end points included DOR, DCR, and PFS per RECIST v1.1 by BICR and OS. Results: No DLTs were observed in the 6 pts enrolled in the safety lead-in phase. 115 pts in the safety lead-in phase or the efficacy expansion phase were treated with the fixed-dose coformulation of quavonlimab and pembro plus lenva 8 or 12 mg. 94 pts (81.7%) were male, median age was 64 y (range, 32-83), and 80 pts (69.6%) had AFP ≤400 ng/mL. As of the June 22, 2023, data cutoff date, median follow-up (time from first dose to database cutoff date or death) was 7.7 mo (range, 0.9-22.1), and 89 pts (77.4%) discontinued treatment, most commonly due to progressive disease (39.1%). Confirmed ORR was 37.4% (95% CI, 28.5-46.9), with 5 CRs (4.3%) and 38 PRs (33.0%). DCR was 79.1% (95% CI, 70.6-86.1). Median DOR was 10.6 mo (range, 1.2+ to 23.1+). Median PFS and OS were 8.2 mo (95% CI, 6.2-10.2) and 22.1 mo (95% CI, 15.5-not reached), respectively; 12-mo PFS and OS rates were 32.2% and 65.2%, respectively. Treatment-related adverse events (TRAEs) occurred in 109 pts (94.8%); most common (≥25%) were hypertension (35.7%) and diarrhea (27.8%). Grade 3-5 TRAEs occurred in 66 pts (57.4%); most common (≥5%) were hypertension (8.7%) and immune-mediated enterocolitis (7.0%). 8 pts (7.0%) died due to AEs; 2 were considered treatment related (acute respiratory failure and subarachnoid hemorrhage). Conclusions: The coformulation of quavonlimab and pembrolizumab in combination with lenvatinib demonstrated manageable safety; further investigation is warranted to understand the efficacy of this triplet as 1L treatment for advanced HCC. Clinical trial information: NCT04740307 .

Talquetamab (tal) + daratumumab (dara) in patients (pts) with relapsed/refractory multiple myeloma (RRMM): Updated TRIMM-2 results.

8003 Background: Tal is a T-cell redirecting bispecific antibody (BsAb) targeting G protein–coupled receptor family C group 5 member D. Dara is an anti-CD38 mAb with direct on-tumor and immunomodulatory actions. Combining immunomodulatory effects of tal + dara may lead to synergistic efficacy. Initial TRIMM-2 (NCT04108195) results showed that SC tal RP2Ds, 0.4 mg/kg QW or 0.8 mg/kg Q2W, + SC dara had promising efficacy and increased CD38+/CD8+ T cells and proinflammatory cytokines. We report updated results with additional pts and longer follow-up. Methods: Pts had MM, ≥3 prior lines of therapy (LOT; including a proteasome inhibitor [PI] and immunomodulatory drug [IMiD]) or were double refractory to a PI and IMiD, and had not received anti-CD38 therapy in ≤90 d. Pts received tal RP2Ds with step-up dosing + dara 1800 mg per approved schedule. AEs were graded per CTCAE v5.0; cytokine release syndrome (CRS) and immune effector cell–associated neurotoxicity syndrome (ICANS) were graded per ASTCT guidelines. Responses were assessed per IMWG criteria. Results: As of Dec 12, 2022 (N = 65), median follow-up was 11.5 mo (range 1.0–27.3). Median age was 63 y (range 37–81); 18% of pts had high-risk cytogenetics; 25% had extramedullary plasmacytomas. Median prior LOT was 5 (range 2–16): 63% penta-drug exposed; 58% triple-class refractory. Prior treatments included anti-CD38 (88% [77% refractory]), anti-BCMA (54% [38%]), BsAb (25% [25%]), and anti-BCMA CAR-T (17% [2%]) therapy. All pts had ≥1 AE (grade [Gr] 3/4 78%), most commonly CRS (78%; all Gr 1/2), dysgeusia (75%), dry mouth (55%), anemia (52%), fatigue (45%), and skin exfoliation (45%). CRS had a median time to onset of 1 d after the most recent dose with median duration of 2 d. 63% of pts had infections (Gr 3/4 22%; Gr 5 3% [n = 2 pneumonia, possibly related to tal + dara]). 38% of pts had neutropenia (Gr 3/4 26%). 85% had postbaseline IgG < 500 mg/dL; of these, 32% received IVIg. ICANS occurred in 3 pts (5%; all Gr 1/2 and resolved in 1–2 d). ORR was 78% (66% ≥VGPR; 45% ≥CR) across RP2Ds (100% in anti-CD38 naïve pts), and responses deepened over time. In pts exposed/refractory to prior therapy, ORRs were 75%/76% for anti-CD38, 74%/64% for anti-BCMA, and 75%/75% for BsAb. Median time to first response was 1 mo (range 0.9–8.3); at 12 mo, 86% of responders (89% of pts with ≥CR) still had responses. At data cutoff, 84% of responders remain on therapy (83%/82% anti-CD38 exposed/refractory). mPFS was 19.4 mo; 12-mo PFS and OS rates were 76% and 93%, respectively. Conclusions: Steroid-sparing tal + dara showed deep and durable responses with promising mPFS in heavily pretreated pts with RRMM, including pts refractory to anti-CD38/BCMA and T-cell redirecting therapy, suggesting combined immunomodulatory actions can yield robust responses in pts with refractory disease. The safety profile was clinically manageable; no new signals were identified with longer follow-up.

AML-119 The Impact of Post-Remission Granulocyte Colony-Stimulating Factor (G-CSF) Use (G-CSFu) in the Phase 3 Studies of Venetoclax (Ven) Combination Treatments in Patients (Pts) With Newly Diagnosed Acute Myeloid Leukemia (AML)

In VIALE-A (NCT02993523) and VIALE-C (NCT03069352), Ven+azacitidine (Aza) and low-dose cytarabine (LDAC), respectively, improved outcomes in pts with intensive chemotherapy (IC)-ineligble newly diagnosed AML. To explore outcomes in pts with G-CSFu. VIALE-A/C, dosing and treatment schedule were previously described. G-CSFu was given per institutional practice. Pts who achieved complete remission (CR) or CR with incomplete hematologic recovery (CRi) were analyzed by G-CSFu. In VIALE-A/C, baseline demographics were similar in Ven-treated pts regardless of G-CSFu. In VIALE-A, 190/286 pts (66%) treated with Ven+Aza and 41/145(28%) pts treated with placebo (PBO)+Aza achieved CR/CRi; 93(49%) and 10(24%) pts with CR/CRi received G-CSF (median time to first G-CSFu[range], 36d[2-483] and 35d[4-127]), respectively. Median duration of response (mDOR) for CR/CRi (95% CI) was not reached (NR; 17.5-NR) and 12.9mo(7.9-17.3) in the Ven+Aza+G-CSF and Ven+Aza+non-G-CSF groups, respectively; DOR at 12mo was 67% and 53%. Among 164 evaluable pts, measurable residual disease response (MRD<10-3) was achieved by 67, of whom 38(57%) had G-CSFu. Median overall survival (mOS[95% CI) was NR(NR-NR) with Ven+Aza+G-CSF and was 21.1mo(15.2-NR) with Ven+Aza+non-G-CSF; 12-mo OS rates were 83% and 71%. Post-remission Gr ≥3 neutropenia and febrile neutropenia (FN) rates were 33%(n=31) and 39%(n=36) with Ven+Aza+G-CSF, and 29%(n=28) and 20%(n=19) with Ven+Aza+non-G-CSF, respectively. Median durations of post-remission Gr ≥3 neutropenia and FN were 12.5d and 8d (Ven+Aza+G-CSF), and 16d and 10.5d (Ven+Aza+non-G-CSF). In VIALE-C, 69/143 pts (48%) treated with Ven+LDAC and 9/68(13%) pts treated with PBO+LDAC achieved CR/CRi; 30(43%) and 2(22%) received G-CSF (median time to first G-CSFu[range], 30d[2-459] and 229d[169-289]), respectively. mDOR was 10.8(4.9-17.8) and 11.8mo(5.9-NR) in the Ven+LDAC+G-CSF and Ven+LDAC+non-G-CSF groups, respectively; DOR at 12mo was 45% and 49%. mOS was 20.8mo(11.9-NR) with Ven+LDAC+G-CSF and 13.7mo(10.8-NR) with Ven+LDAC+non-G-CSF; 12-mo OS were ~68% and ~57%; 9/64 evaluable pts achieved MRD<10-3, of whom 6(67%) had G-CSFu. Post-remission Gr ≥3 neutropenia and FN rates were 53%(n=16) and 23%(n=7) with Ven+LDAC+G-CSF, and 51%(n=20) and 8%(n=3) with Ven+LDAC+non-G-CSF, respectively. Median durations of post-remission Gr≥3 neutropenia and FN were 15d and 6d(Ven+LDAC+G-CSF), and 12.5d and 29d(Ven+LDAC+non-G-CSF). Gr ≥3 neutropenia and FN with G-CSFu trended towards shorter duration, without negative impact on DOR or OS.

1205MO Updated analysis of DESTINY-Gastric02: A phase II single-arm trial of trastuzumab deruxtecan (T-DXd) in western patients (Pts) with HER2-positive (HER2+) unresectable/metastatic gastric/gastroesophageal junction (GEJ) cancer who progressed on or after trastuzumab-containing regimen

Primary results of DESTINY-Gastric02 (NCT04014075; data cutoff [DCO] April 9, 2021), a single-arm, phase II trial of T-DXd in Western pts with HER2+ gastric/GEJ cancer, demonstrated a confirmed objective response rate (cORR) of 38.0% (95% CI, 27.3-49.6), and safety consistent with the established T-DXd safety profile. We report OS and updated efficacy and safety. Pts with centrally confirmed HER2+ (IHC3+ or IHC2+/ISH+ biopsy after progression on trastuzumab-based therapy) unresectable/metastatic gastric/GEJ cancer who progressed on or after 1L therapy received T-DXd 6.4 mg/kg Q3W. The primary endpoint was cORR per RECIST v1.1 by independent central review (ICR). Progression-free survival (PFS) by ICR, duration of response (DOR) by ICR, OS, and patient-reported outcomes based on the European Organization for Research and Treatment of Cancer 5-dimension 5-levels (EQ-5D-5L) quality-of-life (QoL) and Functional Assessment of Cancer Therapy-Gastric (FACT-GA) questionnaires were secondary endpoints. At DCO (November 8, 2021), 79 pts from the US/EU had received T-DXd. 76 pts (96.2%) had received 1 prior line of therapy and 3 (3.8%) had received 2 lines. With a median duration of follow up of 10.2 mo, 10 pts (12.7%) remained on treatment. Median OS was 12.1 mo (95% CI, 9.4-15.4); landmark 12-mo OS rate was 50.6%. cORR was 41.8% (33/79; 4 complete and 29 partial responses). Median DOR was 8.1 mo (95% CI, 5.9-NE). Median PFS was 5.6 mo (95% CI, 4.2-8.3). All pts experienced ≥1 treatment-emergent adverse event (TEAE); 55.7% experienced grade ≥3 TEAEs. The most common TEAEs were nausea (67.1%), vomiting (44.3%) and fatigue (57.0%). Adjudicated drug-related interstitial lung disease/pneumonitis occurred in 8 pts (10.1%); 6 (7.6%) had grade 1-2 and 2 (2.5%) had grade 5. At DCO (April 9, 2021), QoL assessed by EQ-5D-5L and FACT-GA had been maintained over the treatment course. T-DXd continues to demonstrate substantial clinical benefit and a tolerable safety profile in 2L+ Western pts with HER2+ unresectable/metastatic gastric/GEJ cancer.

A multicenter, open-label, phase 2 study of odetiglucan (IMPRIME PGG) and pembrolizumab in patients with metastatic breast cancer (mBCA) who have progressed through prior hormonal therapy.

TPS1115 Background: Hormone receptor (HR) positive/ human epidermal growth factor receptor 2-negative (Her2-) breast cancer is generally considered ‘immunologically cold’ in comparison to TNBC or Her2+ breast cancer. Keynote-028 results showed a modest ORR of 12% to anti-PD1 antibody, pembrolizumab (PEM) in previously treated HR+/ HER2-/programmed death ligand 1-positive (PD-L1-positive) advanced breast cancer patients (pts). With limited options available, there is significant unmet need to expand clinical benefit from ICI. Odetiglucan, a novel beta glucan, acts as a pathogen-associated molecular pattern (PAMP) that drives a cascade of immune activating events. It repolarizes the immunosuppressive microenvironment, activates the maturation of antigen presenting cells and significantly enhances efficacy of ICI therapy in preclinical tumor models. In a Ph2 trial (IMPRIME 1) of odetiglucan + PEM in 44 pts with heavily pretreated metastatic TNBC, an ORR=15.9%, DCR=54.5%, mDOR=12.7mo, mPFS=2.86 mo, 12 mo OS rate=57.6%, and mOS=16.4 mo were observed. Clinical benefit was particularly evident in a subset of pts, mTNBC “converters” (12/44 pts) who were originally diagnosed with ER/PR+ disease and progressed through endocrine therapies +/- CDK4/6 inhibitors. In these 12 pts, an ORR=50%, DCR=83%, mDOR=11.2, mPFS=5.6 mo, 12-mo OS rate=64.8%, and mOS=17.4 mo were observed. Methods: Odetiglucan + PEM is now being explored in pts with hormone-resistant metastatic breast cancer (MBC). This is a phase 2, Simon’s 2-Stage study of MBC pts who have progressed through prior hormonal therapy with &gt;1 CDK4/6 inhibitor. Pts will receive odetiglucan 4 mg/kg/wk + PEM 200 mg Q3wk. Stage 1 will enroll 23 pts. If &gt;4 pts have an objective response after 12 wks of treatment, the study will proceed to Stage 2 enrolling an additional 24 pts (N=47). Rejection of the null hypothesis requires &gt;10 objective responses. Main eligibility criteria include: MBC having failed prior hormonal therapy with &gt;1 CDK4/6 inhibitor, &lt;2 chemotherapies, serum ABA ≥20 µg/mL, and no prior ICI exposure. Primary endpoint is ORR (RECIST v1.1); secondary endpoints are PFS, OS, DCR, DoR, and safety. Exploratory objectives assess impact of the treatment combination on immune activating events in peripheral blood and tumor biopsies, and correlate tumor microenvironmental changes with clinical benefit Select subpopulations may be explored. Point estimates with 95% confidence intervals (CIs) of ORR and DCR will be computed. Medians, first, and third quartiles with 95% CI will be estimated using Kaplan-Meier method for other secondary endpoints. Safety parameters will be summarized. The trial is sponsored by HiberCell, Inc. in collaboration with Merck &amp; Co. ̃25 US sites will participate. Clinical trial information: NCT05159778.

Favezelimab (anti–LAG-3) plus pembrolizumab in patients with anti–PD-1–naive relapsed or refractory (R/R) classical Hodgkin lymphoma (cHL): An open-label phase 1/2 study.

7516 Background: PD-1 inhibitors are a standard of care in pts with R/R cHL but new approaches are still needed to deepen and lengthen responses. Dual blockade of PD-1 and LAG-3 has demonstrated antitumor activity in preclinical models. The multicohort phase 1/2 MK-4280-003 study (NCT03598608) evaluated the safety and efficacy of favezelimab (MK-4280), a humanized IgG4 LAG-3 inhibitor, plus pembrolizumab (pembro; a PD-1 inhibitor) in pts with R/R hematologic malignancies. This analysis focused on anti–PD-1–naïve pts with R/R cHL (cohort 1). Methods: This study included a safety lead-in phase (part 1) to determine the recommended phase 2 dose (RP2D) followed by a dose-expansion phase (part 2). Eligible pts in cohort 1 must have R/R cHL after autologous stem cell transplantation (ASCT) or be ineligible for ASCT and have had no prior anti–PD-1 therapy. In part 1, patients from all cohorts received pembro IV 200 mg Q3W and favezelimab IV 200 mg or 800 mg Q3W. Dose escalation followed the mTPI design. In part 2, pts received pembro + favezelimab at the established RP2D for up to 35 cycles. Primary end point was safety. Secondary end point was ORR. DOR, PFS, and OS were exploratory end points. Results: Only 1 dose-limiting toxicity (DLT; autoimmune hepatitis [grade 4]) was identified among the first 6 pts from all cohorts in part 1 at the favezelimab 200 mg dose; thus, the dose was escalated to 800 mg. No DLTs were observed in the 15 additional pts treated at the 800 mg dose. The RP2D for the combination was defined as 800 mg Q3W + pembro 200 mg Q3W. In cohort 1, 30 pts were enrolled; median age was 40 years, 53% had ECOG PS 0, and 80% had ≤3 prior lines of therapy. After a median follow-up of 13.5 mo, ORR for cohort 1 was 73% (95% CI, 54-88; CR, 7 pts [23%]; PR, 15 pts [50%]). 28 of 30 pts (93%) had reduction from baseline in target lesions. Median DOR was not reached (NR; 95% CI, 0+ to 23+ mo); 6 pts (51%) had response ≥12 mo. Median PFS was 19 mo (95% CI, 8-NR); 12-mo PFS rate was 57%. Median OS was NR (95% CI, NR-NR); 12-mo OS rate was 94%. As of the database cutoff (Nov 1, 2021), 9 of 30 pts had discontinued (3 AEs; 6 PD). Treatment-related AEs (TRAE) occurred in 26 pts (87%); most common (≥10%) were hypothyroidism (27%), fatigue (20%), infusion-related reactions (20%), headache (17%), and arthralgia, hyperthyroidism, myalgia, and nausea (10% each); grade 3 or 4 TRAEs occurred in 6 pts (20%). 10% of pts discontinued due to TRAEs. No treatment-related deaths occurred. Conclusions: Favezelimab 800 mg + pembrolizumab 200 mg Q3W demonstrated a tolerable safety profile and effective antitumor activity in pts with anti–PD-1–naïve R/R cHL. Further studies will be useful to compare its activity to that of pembrolizumab alone. Clinical trial information: NCT03598608.

Ramucirumab, avelumab, and paclitaxel (RAP) as second-line treatment in gastro-esophageal adenocarcinoma, a phase II trial of the Arbeitsgemeinschaft Internistische Onkologie (AIO).

4051 Background: Combination of ramucirumab and paclitaxel is a standard second line therapy in gastro-esophageal adenocarcinoma (GEAC) (RAINBOW trial, Wilke et al., 2014). We integrated the PD-L1 inhibitor avelumab into this regimen aiming for synergistic efficacy. Methods: In a multicenter phase II trial (NCT03966118) pts with metastatic GEAC, after progression on platinum / fluoropyrimidine based palliative 1st-line, ECOG 0 or 1, were treated with ramucirumab 8 mg/kg (d1,15) + avelumab 10 mg/kg (d1,15) + paclitaxel 80 mg/m² (d1,8,15), q4w. Sample size calculation was based on a Simon 2-stage design with overall survival rate at 6 months as the primary endpoint (H0≤50%, H1≥65%). Results: 60 pts were enrolled, 59 were evaluable (ITT), median age 64.0 yrs (range 18-81), male 80%, female 20%, primary gastric 52%, GEJ 48%, histology intestinal 59.6%, diffuse 24.6%, mixed 15.8%. Previous treatment with platin/fluoropyrimidine 100%, previous taxanes 66%. At central pathology MSI-H 7%, PD-L1 CPS &lt; 5: 54%; ≥5: 41%, NA 5%. Response by investigator (%) CR 3.4, PR 27.1, SD 49.2, PD 20.3; DCR 79.7%, independent radiology review will be presented. DOR: 8.2 mo (95%CI 6.7-9.7), PFS 5.4 mo (95%CI 4.2-6.6); 6-mo OS rate 71.2%; 12-mo OS rate 45.8%; med OS (ITT) 10.6 mo (95%CI 8.2-13.1), med OS CPS &lt; 5: 9.4 mo (95%CI 7.2-11.2), CPS ≥5: 14.0 mo (95%CI 12.8-15.3), translational data (ct-DNA) will be analysed. Treatment was generally well tolerated and no unexpected toxicities occurred: Grade 3/4 AE above 5%: anemia 5%, leucopenia 12%, neutropenia 22%, diarrhea 5%, pain 10%, peripheral neuropathy 10%, hypertension 5%, non-neutropenic infection 5% including 1 CTC grade 5 due to an esophago-tracheal fistula. Conclusions: The med OS of 10.6 mo (in a population of 66% pretreated with taxanes) compares very favourably to 8.6 mo in the Western population RAINBOW trial (Shitara et al., 2016) and 7.6 mo in the RAMIRIS trial (Lorenzen et al., 2022). PD-L1 CPS≥ 5 seems to predict for an even better efficacy (med OS 14.0 mo). Second-line RAP is a very efficacious and well tolerated combination. Clinical trial information: NCT03966118.

Favezelimab (anti–LAG-3) plus pembrolizumab in patients with relapsed or refractory (R/R) classical Hodgkin lymphoma (cHL) after anti–PD-1 treatment: An open-label phase 1/2 study.

7545 Background: PD-1 inhibitors are a standard of care for R/R cHL but optimal therapy after anti–PD-1 therapy failure is yet to be defined. LAG-3/PD-1 coblockade has demonstrated antitumor activity in preclinical models. This multicohort phase 1/2 study (NCT03598608) evaluated the safety and efficacy of favezelimab (MK-4280), a humanized IgG4 LAG-3 inhibitor, plus the PD-1 inhibitor pembrolizumab (pembro) in pts with R/R hematologic malignancies. Cohort 2 focused on pts with R/R cHL refractory to anti–PD-1 therapy. Methods: This study included a safety lead-in phase (part 1) to determine recommended phase 2 dose (RP2D) followed by a dose-expansion phase (part 2). Eligible pts in cohort 2 had R/R cHL, relapsed after or were ineligible for autologous stem cell transplantation (ASCT), and progressed after ≥2 doses of anti–PD-1 therapy (within 12 weeks of last dose). In part 1, pts from all cohorts received pembro IV 200 mg Q3W and favezelimab IV 200 mg or 800 mg Q3W. Dose-finding based on occurrence of dose-limiting toxicities (DLT) was determined using an mTPI design. In part 2, pts received pembro + favezelimab at the established RP2D for up to 35 cycles. Primary end point was safety. Secondary end point was ORR. DOR, PFS, and OS were exploratory. Results: Only 1 DLT (autoimmune hepatitis [grade 4]) was observed among the first 6 pts from all cohorts in part 1 at the favezelimab 200 mg dose; thus, the dose was escalated to 800 mg. No DLTs were observed in 15 additional pts at the 800 mg dose. Favezelimab RP2D was defined as 800 mg Q3W + pembro 200 mg Q3W. In cohort 2, 33 pts were enrolled; median age was 37 yrs, 64% had ECOG PS 0, and 94% had ≥4 prior lines of therapy. After a median follow-up of 16.5 mo, ORR for pts receiving favezelimab 800 mg (n = 29) was 31% (95% CI, 15-51; CR, 2 [7%]; PR, 7 [24%]); 66% of responders had an anti–PD-1–based regimen as most recent line of therapy at study entry. 23 of 29 pts (79%) had reduction from baseline in target lesions. Median DOR for pts who received favezelimab 800 mg was not reached (NR; 95% CI, 0+ to 14+ mo). For all pts in cohort 2, median PFS was 9 mo (95% CI, 5-15); 12-mo PFS rate was 39%. Median OS was 26 mo (95% CI, 26-NR); 12-mo OS rate was 91%. At database cutoff (Nov 1, 2021), 20 pts discontinued treatment (7 AEs, 11 PD/clinical progression, 2, withdrawal/physician decision). TRAEs occurred in 28 pts (85%); most common ( &gt; 10%) were hypothyroidism (18%), nausea and fatigue (15% each), and arthralgia and diarrhea (12% each); grade 3 or 4 TRAEs occurred in 6 pts (18%); 18% discontinued treatment due to TRAEs. No treatment-related deaths occurred. Conclusions: Favezelimab 800 mg + pembro 200 mg Q3W showed a tolerable safety profile and effective antitumor activity in heavily pretreated pts with R/R cHL whose disease had progressed after anti–PD-1 therapy, suggesting that the combination may reinduce a response in these pts. Clinical trial information: NCT03598608.

Updated results of the FOENIX-CCA2 trial: Efficacy and safety of futibatinib in intrahepatic cholangiocarcinoma (iCCA) harboring FGFR2 fusions/rearrangements.

4009 Background: Survival outcomes are historically poor in patients (pts) with advanced/metastatic iCCA, with median overall survival (mOS) times of approximately 1 year with first-line gemcitabine plus cisplatin and approximately 6 months with second-line chemotherapy. Futibatinib, a highly selective, irreversible FGFR1–4 inhibitor, demonstrated efficacy with durable responses in pts with iCCA harboring FGFR2 fusion/rearrangements in the pivotal FOENIX-CCA2 phase 2 study (NCT02052778). At the primary analysis of this trial (data cutoff: October 1, 2020), an objective response rate (ORR) of 41.7% was observed, with a median duration of response (mDOR) of 9.7 mo. Here, we report updated efficacy (including mature OS data) and safety data from the final analysis with an additional 8 mo of follow-up. Methods: FOENIX-CCA2 was a single-arm phase 2 study that enrolled pts with advanced/metastatic iCCA with FGFR2 fusion/rearrangement and progressive disease (PD) after ≥1 prior treatment (tx; including gemcitabine plus platinum-based chemotherapy). Pts received futibatinib 20 mg once daily until PD/intolerability. The primary endpoint was ORR per RECIST v1.1 by independent central review. Secondary endpoints were DOR, disease control rate (DCR), progression-free survival (PFS), OS, safety, and patient-reported outcomes. Results: At the time of the final data cutoff (May 29, 2021), median follow-up was 25.0 mo, and 96/103 pts (93%) had discontinued tx. The median number of tx cycles was 13.0 for a median tx duration of 9.1 mo. The confirmed ORR was 41.7% (43/103) and thereby the same as of the primary analysis, as was the DCR (at 82.5%). The ORR was consistent across pt subgroups. The mDOR was 9.5 mo, and 74% of responses lasted ≥6 mo. mPFS was 8.9 mo, with a 12-mo PFS rate of 35.4%. Mature mOS was 20.0 mo, with a 12-mo OS rate of 73.1% . No new safety signals were identified. Common tx-related adverse events (TRAEs) included hyperphosphatemia (85%), alopecia (33%), dry mouth (30%), diarrhea (28%), dry skin (27%), and fatigue (25%). TRAEs resulted in tx discontinuation in 4 pts (4%). No tx-related deaths occurred. Quality of life was maintained from baseline to tx cycle 13. Conclusions: Findings from the final analysis of FOENIX-CCA2 confirm the results of the primary analysis and reinforce the durable efficacy and continued tolerability of futibatinib in previously treated pts with advanced/metastatic iCCA harboring FGFR2 fusion/rearrangements. Mature OS data were consistent with data from the primary analysis and far exceed historical data in this patient population. Clinical trial information: NCT02052778.

Prophylactic Corticosteroid Use with Axicabtagene Ciloleucel (Axi-Cel) in Patients (Pts) with Relapsed/Refractory Large B-Cell Lymphoma (R/R LBCL): One-Year Follow-up of ZUMA-1 Cohort 6 (C6)

Prophylactic Corticosteroid Use with Axicabtagene Ciloleucel (Axi-Cel) in Patients (Pts) with Relapsed/Refractory Large B-Cell Lymphoma (R/R LBCL): One-Year Follow-up of ZUMA-1 Cohort 6 (C6)

ATG-010 Plus Low-Dose Dexamethasone (Sd) in Chinese Relapsed/Refractory Multiple Myeloma (RRMM) Patients Previously Received Chimeric Antigen Receptor T-Cell (CAR-T)

Background:There are limited treatment options for multiple myeloma (MM) patients who have a disease progression after CAR-T therapy. ATG-010 (selinexor) is a novel, oral selective inhibitor of nuclear export, inhibiting exportin 1. US FDA has approved selinexor plus low dose dexamethasone (Sd) to treat patients (pts) with penta-refractory MM. MARCH study, a single arm, Phase 2, registrational study evaluating Sd in Chinese RRMM pts, achieved an overall response rate (ORR) of 29.3% (95% CI: 19.7, 40.4), rejecting the null hypothesis of the study. Given its unique and novel mechanism of action, Sd preserves anti-tumor activity regardless of specific prior therapies. In the MARCH study, encouraging activity was demonstrated in a small group of Chinese RRMM pts previously exposed to CAR-T therapy.Methods:The study enrolled 82 pts previously exposed and refractory to a proteasome inhibitor (PI), an immunomodulatory agent (IMiD), and last line of therapy. Among them, 10 had received lymphodepleting conditioning followed by CAR-T cell therapy before study screening. ATG-010 (80mg) plus dexamethasone (20mg) was administered orally twice weekly. Response was assessed by an independent review committee.Results:Among 10 pts, 8 were male and 2 were female. Median age was 58.5 years. Median duration from MM initial diagnosis was 5.2 years. A total of 6 pts (60.0%) had high-risk cytogenetic abnormalities, including 4 pts (40.0%) with del (17p). Three pts had baseline plasmacytoma. Five pts (50%) experienced very rapid disease progression as indicated by a median of 46.2% increase of tumor burden from screening to Cycle 1 Day 1. Patients were heavily pre-treated with a median of 9.5 prior regimens (range: 5-12), with 8 receiving more than 6 regimens. Four pts were exposed to daratumumab (triple-class exposure). ORR was 50% including 1 very good partial response and 4 partial responses. Disease control rate defined as SD and above was 70%. Median duration of response was 1.4 months (mo) (95% CI: 0.96, NE). Median progression free survival was 1.9 mo (95% CI: 0.93, 3.74). xx pts (xx%) pts died; median overall survival was not reached, and estimated 12-mo OS rate was 68.6%.Adverse events were consistent with those events previously reported with Sd regimen in RRMM patients. The most common grade≥3 treatment emergent adverse events (TEAEs) included anemia, thrombocytopenia, neutropenia and nausea. Most events were manageable with appropriate supportive care or dose modification. Four pts (40%) experienced TESAEs, including anemia, pneumonia, neutropenia, and upper gastrointestinal hemorrhage. There were no TEAEs leading to treatment discontinuation or death.Conclusions:Sd was able to induce an encouraging response with a manageable safety profile for a group of Chinese RRMM patients desperately needing treatment after failing CAR-T therapy. With the small sample size, further investigation is warranted, including using ATG-010 in combination with other anti-MM therapies to potentially enhance and prolong therapeutic benefit. DisclosuresYu: Antengene Therapeutics Ltd.: Current Employment. Wang: Antengene Therapeutics Ltd.: Current Employment. Yu: Antengene Therapeutics Ltd.: Current Employment. Yang: Antengene Therapeutics Ltd.: Current Employment. Lynch: Antengene Therapeutics Ltd.: Current Employment.

Camrelizumab plus famitinib for advanced renal cell carcinoma or unresectable urothelial carcinoma: Updated results from a phase II trial.

4550 Background: Considering the synergistic/additive effect of PD-1 blockade and angiogenesis inhibition, we conducted an open-label, multi-center phase II study of camrelizumab (an anti-PD-1 antibody) plus famitinib (a TKI against VEGFR-2, PDGFR, c-kit, and FGFR) in pts with heavily treated advanced renal cell carcinoma (RCC) and unresectable urothelial carcinoma (UC). Methods: Based on an adaptive two-stage design, 22 pts were enrolled in the RCC and UC cohort, respectively, at stage 1; if there were ≥7 responders of the 22 pts, enrollment would be extend to 33 at stage 2. Pts received famitinib 20 mg orally QD plus camrelizumab 200 mg IV Q3W. Primary endpoint was ORR per RECIST v1.1. Preliminary data at stage 1 were reported at ASCO 2020 annual meeting (#5085). More than 7 pts in each cohort had CR/PR during stage 1; enrollment of stage 2 had been completed, and the data are firstly reported here. Results: 74 pts (38 advanced RCC and 36 unresectable UC) were enrolled from Jan 23, 2019 to Dec 14, 2020. In RCC cohort, 65.8% of pts had received ≥1 prior VEGFR inhibitors. In UC cohort, all pts had progressed on or relapsed after a platinum-containing chemotherapy. As of Jan 10, 2021, median time from enrollment to data cutoff was 18.8 mos (range, 8.5-22.7) for RCC cohort and 7.0 mos (range, 0.9-23.6) for UC cohort. In RCC cohort, ORR was 63.2% (95% CI, 46.0-78.2; 24 PRs), DCR was 89.5% (95% CI, 75.9-95.8), median DOR was not reached (range 2-19+ mos), mPFS was not reached, and 12-mo OS rate was 88.0%. Most pts (92.1%) had reduction in target lesions, and median reduction was 47% from baseline. ORR was 84.6% (95% CI, 57.8-97.3; 11/13) for untreated RCC pts and 52.0% (95% CI, 31.3-72.2; 13/25) for pre-treated pts; DCR was 100% (95% CI, 77.2-100.0) and 84.0% (95% CI, 65.3-93.6), mPFS was not reached and 13.4 mos (95% CI: 4.1-21.0), respectively. In UC cohort, of the 33 pts with post-baseline efficacy evaluation, ORR was 33.3% (95% CI, 19.8-50.4; 1 CR, 10 PRs), DCR was 60.6% (95% CI, 43.7-75.3), median DOR was not reached (range 1.0+-16.7+ mos), mPFS was 6.4 mos (95% CI, 2.1-11.8), and mOS was not reached. ORR trended to be higher for bladder cancer (43.8%, 7/16) than upper tract urothelial carcinoma (25.0%, 4/16). Treatment-related AEs (TRAEs) occurred in 97.3% of 74 pts. Grade 3 or 4 TRAEs occurred in 63.5% of pts, mainly hypertension (23.4%), decreased platelet count (21.3%), proteinuria (17.0%), anemia (14.9%), and palmar-plantar erythrodysesthesia syndrome (14.9%). 1 pt died of TRAE (multiple organ dysfunction syndrome). Conclusions: Camrelizumab plus famitinib showed potent anti-tumor activity in pts with advanced RCC and UC with no new safety concerns. Additionally, promising ORR and durable DOR were observed in pts with heavily-treated RCC. These results support further investigation in these settings. Clinical trial information: NCT03827837.

KEYNOTE-199 cohorts (C) 4 and 5: Phase II study of pembrolizumab (pembro) plus enzalutamide (enza) for enza-resistant metastatic castration-resistant prostate cancer (mCRPC).

5543 Background: Initial evidence suggests activity of pembro + enza in patients (pts) resistant to enza. We present results from the multicohort phase II study KEYNOTE-199 (NCT02787005) in chemotherapy-naive pts with mCRPC treated with pembro + enza after progression with enza and who had RECIST-measurable (C4) or bone-predominant (C5) disease. Methods: Pts who did or did previously receive abiraterone and for whom enza treatment failed after clinically meaningful response received pembro 200 mg Q3W, with continuation of enza for up to 2 y or until progression, toxicity, or withdrawal. End point was ORR per RECIST v1.1 (C4) by blinded independent central review (primary); DOR (C4), time to PSA progression, rPFS, OS, and safety. Results: A total of126 pts (C4, 81; C5, 45) were treated. Median (range) PSA was 31 ng/mL (0.4-1667) in C4 and 19 ng/mL (1-1750) in C5.Median (range) time from enrollment to data cut off was 15 mo (7-21) in C4 and 19 mo (7-21) in C5. In C4, ORR (95% CI) was 12% (6-22; 2 CRs, 8 PRs) and median (range) DOR was 6 mo (3+ to 13); 60% of pts had DOR ≥6 mo. DCR (CR + PR + SD) was 51% in C4 and C5. Median (95% CI) time to PSA progression was 4 mo (4-4) in C4 and 4 mo (4-4) in C5. Median (95% CI) rPFS was 4 mo (3-6) for C4 and 4 mo (3-6) for C5; 12-mo rPFS rate was 17% in C4 and 23% in C5. Median (95% CI) OS was NR (16-NR) in C4 and 19 (14-NR) mo in C5; 12-mo OS rate was 70% in C4 and 75% in C5. Shorter median OS was more associated with prior enza treatment &lt;6 mo than with prior enza treatment ≥6 mo. Liver metastasis was associated with shorter median OS however, median OS in visceral disease subgroups appeared longer than expected. Any-grade/grade ≥3 treatment-related AEs occurred in 75%/26% of pts in C4 and 69%/24% in C5. Two pts in C5 died of immune-related AEs (Miller Fisher syndrome and myasthenia gravis). Any-grade/grade 3/4 rash (regardless of relatedness) was higher than that in prior reports for individual agents (33%/6%). Conclusions: Pembro + enza after enza resistance had manageable safety and showed antitumor activity for RECIST-measurable and bone-predominant mCRPC. This combination is being evaluated in an ongoing phase III combination trial. Clinical trial information: NCT02787005 . [Table: see text]