Nivolumab (NIVO) + ipilimumab (IPI) combination therapy in patients (pts) with advanced hepatocellular carcinoma (aHCC): Subgroup analyses from CheckMate 040.

520 Background: In the phase 3 CheckMate 9DW study (NCT04039607), 1L NIVO + IPI demonstrated significant overall survival (OS) benefit vs LEN/SOR, higher objective response rate (ORR) with durable responses, and manageable safety in uHCC. We present efficacy by best overall response (BOR) subgroups and baseline characteristics, and additional safety analyses from the preplanned interim analysis. Methods: Patients (pts) with previously untreated HCC not eligible for curative surgical or locoregional therapies, Child-Pugh score 5 or 6, and ECOG performance status 0 or 1 were randomized 1:1 to receive NIVO 1 mg/kg + IPI 3 mg/kg Q3W (up to 4 cycles), then NIVO 480 mg Q4W or LEN 8 mg or 12 mg QD or SOR 400 mg BID until disease progression or unacceptable toxicity. NIVO was given for a maximum of 2 years. The primary endpoint was OS; secondary endpoints included ORR and duration of response (DOR) per blinded independent central review (BICR) using RECIST v1.1. Results: A total of 668 pts were randomized to NIVO + IPI (n = 335) or LEN/SOR (n = 333). At a median follow-up of 35.2 (range 26.8–48.9) months (mo), median OS (95% CI) was 23.7 (18.8–29.4) mo with NIVO + IPI vs 20.6 (17.5–22.5) mo with LEN/SOR (HR 0.79 [95% CI 0.65–0.96]; P = 0.0180). ORR (95% CI) per BICR was significantly higher with NIVO + IPI vs LEN/SOR (36% [31–42] vs 13% [10–17]; P < 0.0001); median DOR (95% CI) was 30.4 (21.2–not estimable [NE]) mo vs 12.9 (10.2–31.2) mo. Survival benefit of NIVO + IPI vs LEN/SOR was observed across BOR subgroups at the 24-week landmark timepoint (Table). In subgroup analyses, ORR (95% CI) per BICR was higher with NIVO + IPI vs LEN/SOR across HCC etiologies (uninfected: 35% [26–44] vs 8% [4–15]; HBV infected: 25% [17–34] vs 17% [10–25]; HCV infected: 50% [39–61] vs 16% [9–25]) and in pts with Barcelona Clinic Liver Cancer stage ≤B (33% [23–43] vs 13% [6–21]) or stage C (37% [31–44] vs 14% [10–19]). Safety data are shown in the Table. Additional exploratory analyses will be presented. Conclusions: These additional analyses from CheckMate 9DW demonstrate the efficacy and manageable safety of 1L NIVO + IPI in uHCC and further support its use as a potential standard-of-care treatment option in this setting. Clinical trial information: NCT04039607 . OS by BOR at week 24 landmark NIVO + IPI LEN/SOR BOR CR + PR (n = 101) SD a (n = 105) PD (n = 47) CR + PR (n = 28) SD a (n = 212) PD (n = 31) Median OS (95% CI), mo NR (44.4–NE) 30.0(23.5–37.8) 16.0(12.0–18.7) 28.3(20.6–NE) 22.5(20.5–24.8) 13.5(8.7–25.3) All treated pts NIVO + IPI (n = 332) LEN/SOR (n = 325) Any-grade/grade 3–4 TRAEs, n (%) 278 (84)/137 (41) 297 (91)/138 (42) Hepatobiliary 44 (13)/35 (11) 15 (5)/10 (3) Cardiovascular 10 (3)/3 (< 1) 138 (42)/39 (12) Hemorrhagic 2 (< 1)/1 (< 1) 20 (6)/5 (2) a Includes non-CR/non-PD. CR, complete response; NR, not reached; PD, progressive disease; PR, partial response; SD, stable disease; TRAE, treatment-related adverse event.

LBA4008 Background: First-line therapies based on programmed death ligand 1 (PD-L1) inhibitors are standard of care (SOC) in uHCC and demonstrate improved outcomes over SOR; however, prognosis remains poor and there is an unmet need for alternative therapies with long-term benefits. Second-line NIVO + IPI demonstrated clinically meaningful efficacy and manageable safety in SOR-treated patients (pts) with HCC in CheckMate 040, leading to its accelerated approval in the United States. We report first results from the preplanned interim analysis of the phase 3, open-label, randomized CheckMate 9DW trial evaluating the efficacy and safety of NIVO + IPI vs LEN or SOR as first-line therapy for pts with uHCC (NCT04039607). Methods: Adult pts with previously untreated HCC not eligible for curative surgical or locoregional therapies, Child-Pugh score 5–6, and ECOG performance status 0–1 were included. Pts were randomly assigned 1:1 to receive NIVO 1 mg/kg + IPI 3 mg/kg Q3W (up to 4 cycles) followed by NIVO 480 mg Q4W or investigator’s choice of LEN 8 mg or 12 mg QD or SOR 400 mg BID until disease progression or unacceptable toxicity. NIVO was given for a maximum of 2 years. The primary endpoint was overall survival (OS). Secondary endpoints included objective response rate (ORR) and duration of response (DOR) per blinded independent central review (BICR) using RECIST v1.1. Results: In total, 668 pts were randomized to NIVO + IPI (n = 335) or LEN/SOR (n = 333); among 325 pts treated in the LEN/SOR arm, 275 (85%) received LEN. After a median (range) follow-up of 35.2 (26.8–48.9) months (mo), median OS was 23.7 mo with NIVO + IPI vs 20.6 mo with LEN/SOR (HR, 0.79; 95% CI, 0.65–0.96; P = 0.0180) (Table), with respective 24-mo OS rates (95% CI) of 49% (44–55) vs 39% (34–45). ORR was higher with NIVO + IPI (36%) vs LEN/SOR (13%; P < 0.0001); complete response was observed in 7% of pts with NIVO + IPI vs 2% with LEN/SOR. Median DOR was 30.4 mo with NIVO + IPI vs 12.9 mo with LEN/SOR (Table). A summary of treatment-related adverse events (TRAEs) is shown in the Table. Conclusions: NIVO + IPI demonstrated statistically significant OS benefit vs LEN/SOR in pts with previously untreated uHCC, as well as higher ORR and durable responses with a manageable safety profile. These results support this combination as a potential new first-line SOC for uHCC. Clinical trial information: NCT04039607 . [Table: see text]

478 Background: The programmed death-1 inhibitor NIVO had durable responses and a manageable safety profile in pts with aHCC in CheckMate 040 (NCT01658878; El-Khoueiry et al. Lancet 2017) and is approved in the United States, Canada, Australia, and elsewhere for sorafenib (SOR)-treated pts with aHCC. In another CheckMate 040 cohort, NIVO + IPI combination therapy had durable responses in SOR-treated pts with aHCC, with objective response rates (ORRs) > 30% in each dosing arm (Yau et al. J Clin Oncol 2019). CABO is also approved for SOR-treated pts with aHCC; a pivotal phase 3 trial reported median overall survival (OS) of 10.2 mo (Abou-Alfa et al. N Engl J Med 2018). This is the first report of efficacy and safety of NIVO + CABO +/- IPI (doublet and triplet) combinations in pts with aHCC. Methods: SOR-naive or -experienced pts with aHCC were randomized to 2 arms: [1] NIVO 240 mg Q2W + CABO 40 mg daily or [2] NIVO 3 mg/kg Q2W + IPI 1 mg/kg Q6W + CABO 40 mg daily. Treatment continued until intolerable toxicity or disease progression. Primary endpoints included ORR (investigator assessed using RECIST v1.1) and safety/tolerability. Data cutoff was January 2019. Results: 71 pts were randomized to NIVO + CABO (n = 36) or NIVO + IPI + CABO (n = 35). Investigator-assessed ORR was 17% (6 pts with partial response [PR]) in the NIVO + CABO arm and 26% (9 pts with PR) in the NIVO + IPI + CABO arm. Disease control rate was 81% for the NIVO + CABO arm and 83% for the NIVO + IPI + CABO arm; median progression-free survival was 5.5 mo for the NIVO + CABO arm and 6.8 mo for the NIVO + IPI + CABO arm. Median OS was not reached in either arm. Grade 3-4 treatment-related adverse events (TRAEs) were reported in 15 pts (42%) in the NIVO + CABO arm and 25 pts (71%) in the NIVO + IPI + CABO arm and led to discontinuation in 1 (3%) and 7 (20%) pts, respectively. No new safety signals were observed in either arm. Updated data describing the efficacy and safety of the combinations will be shown. Conclusions: In pts with aHCC, NIVO + CABO +/- IPI combination therapy led to clinically meaningful responses. Although the triplet had a higher rate of TRAEs observed than the doublet regimen, the majority of AEs were manageable and reversible. Clinical trial information: NCT01658878.

4012 Background: NIVO monotherapy (mono) is approved for sorafenib (SOR)-treated pts with HCC based on data from CheckMate 040 (NCT01658878), which reported an objective response rate (ORR) of 14% and median overall survival (mOS) of 16 months (mo). This is the first report of efficacy and safety of the NIVO + IPI combination in SOR-treated pts with aHCC. Methods: Pts were randomized to 3 arms: [A] NIVO 1 mg/kg + IPI 3 mg/kg Q3W (4 doses) or [B] NIVO 3 mg/kg + IPI 1 mg/kg Q3W (4 doses), each followed by NIVO 240 mg Q2W, or [C] NIVO 3 mg/kg Q2W + IPI 1 mg/kg Q6W. Treatment continued until intolerable toxicity or disease progression. Primary endpoints included safety and tolerability. Secondary endpoints included ORR (BICR per RECIST v1.1), duration of response (DOR), disease control rate (DCR), and OS. Cutoff was 25 Sep 2018. Results: 148 SOR-treated pts were randomized. Minimum follow-up for OS from last pt randomization date to data cutoff was 24 mo. At baseline: 88% had vascular invasion or extrahepatic spread, 91% had BCLC stage C, 84% discontinued SOR due to disease progression and 14% due to toxicity. Overall, ORR was 31% (7 had a complete response [CR]) with a median DOR of 17 mo; DCR was 49% and 24-mo OS rate was 40%. Pts in arm A had a mOS of 23 mo and 4 pts had a CR. The table shows additional efficacy results by arm. Overall, NIVO + IPI was well tolerated; 37% of pts had a grade 3–4 treatment-related adverse event (TRAE; most common: pruritus and rash); 5% had grade 3–4 TRAEs leading to discontinuation. Conclusions: NIVO + IPI led to clinically meaningful responses and had an acceptable safety profile in SOR-treated pts, with an ORR twice that of NIVO mono (31% and 14%, respectively). Pts in arm A had the most promising mOS of 23 mo. Clinical trial information: NCT01658878. [Table: see text]

LBA38_PR - CheckMate 459: A randomized, multi-center phase III study of nivolumab (NIVO) vs sorafenib (SOR) as first-line (1L) treatment in patients (pts) with advanced hepatocellular carcinoma (aHCC)

LBA143 Background: The CheckMate 8HW study met its dual primary endpoint with NIVO + IPI demonstrating superior progression-free survival (PFS) by blinded independent central review (BICR) vs chemotherapy (chemo) in patients (pts) with centrally confirmed MSI-H/dMMR mCRC in the first-line (1L) setting (HR 0.21; 95% CI 0.14–0.32; P < 0.0001). We report first results from the other dual primary endpoint of PFS for NIVO + IPI vs NIVO across all lines of therapy in pts with centrally confirmed MSI-H/dMMR mCRC. Methods: Immunotherapy-naive pts with unresectable or mCRC and MSI-H/dMMR status by local testing who had received 0 or 1 prior line of therapy were randomized 2:2:1 to (i) NIVO (240 mg) Q2W (6 doses, then NIVO 480 mg Q4W), (ii) NIVO (240 mg) + IPI (1 mg/kg) Q3W (4 doses, then NIVO 480 mg Q4W), or (iii) chemo ± targeted therapies. Pts who had received ≥ 2 prior lines of therapy were randomized 1:1 to the NIVO + IPI or NIVO arms. Treatments continued until disease progression or unacceptable toxicity (all arms), or a maximum of 2 years (NIVO ± IPI arms). Results: Across all lines of therapy,707 pts were randomized to NIVO + IPI (n = 354) or NIVO (n = 353); 55% and 52% received study treatment in the 1L setting, respectively. Of all randomized pts, 296 in the NIVO + IPI arm and 286 in the NIVO arm had centrally confirmed MSI-H/dMMR status. With 47.0 months (mo) of median follow-up (range, 16.7–60.5), NIVO + IPI demonstrated clinically meaningful and statistically significant improvement in PFS by BICR vs NIVO (HR 0.62; 95% CI 0.48–0.81; P = 0.0003) and higher 12-, 24-, and 36-mo PFS rates vs NIVO (Table). Objective response rate (ORR) by BICR was significantly higher with NIVO + IPI vs NIVO (71% vs 58%; P = 0.0011; Table); best overall response of progressive disease was reported in 10% and 19% of pts, respectively. No new safety concerns were identified (Table). Conclusions: In the first randomized study to compare dual- vs single-agent immunotherapy in MSI-H/dMMR mCRC, NIVO + IPI demonstrated superior PFS vs NIVO across all lines of therapy, with a manageable safety profile. These results establish NIVO + IPI as the potential new standard-of-care treatment for MSI-H/dMMR mCRC. Clinical trial information: NCT04008030 . Efficacy by BICR (all lines; centrally confirmed MSI-H/dMMR by IHC and/or PCR test) NIVO + IPI(n = 296) NIVO(n = 286) Median PFS (95% CI), mo NR (53.8–NE) 39.3 (22.1–NE) HR (95% CI); P value 0.62 (0.48–0.81); 0.0003 PFS rate (12/24/36-mo), % 76/71/68 63/56/51 ORR, n (%); 95% CI, % 209 (71); 65–76 165 (58); 52–64 P value 0.0011 Safety (all lines; all treated), n (%) NIVO + IPI (n = 352) NIVO (n = 351) Any-grade/grade 3–4 TRAEs 285 (81)/78 (22) 249 (71)/50 (14) Any-grade/grade 3–4 TRAEs leading to discontinuation 48 (14)/33 (9) 21 (6)/14 (4) Treatment-related deaths 2 (< 1) 1 (< 1) IHC, immunohistochemistry; NE, not estimable; NR, not reached; PCR, polymerase chain reaction; TRAE, treatment-related adverse event.

3510 Background: NIVO ± IPI is approved in previously treated pts with MSI-H/dMMR mCRC in the US, EU, and Japan, based on findings from the phase 2 CheckMate 142 study (NCT02060188). NCCN guidelines include NIVO + IPI as an initial therapy option for pts with MSI-H/dMMR mCRC. Results from a ~5-year follow-up from CheckMate 142 cohorts 1–3 (C1–3) are reported here. Methods: In this non-randomized, multicohort study, pts with MSI-H/dMMR mCRC were treated as follows: C1 (2L+; NIVO 3 mg/kg Q2W), C2 (2L+; NIVO 3 mg/kg + IPI 1 mg/kg Q3W [4 doses], followed by NIVO 3 mg/kg Q2W) and C3 (1L; NIVO 3 mg/kg Q2W + IPI 1 mg/kg Q6W), until disease progression or unacceptable toxicity. The primary endpoint was objective response rate (ORR) by investigator assessment (INV) per RECIST v1.1. Other key endpoints were disease control rate (DCR), duration of response (DOR), progression-free survival (PFS), all by INV and blinded independent central review; overall survival (OS), and safety. Results: In C1 (N = 74), C2 (N = 119), and C3 (N = 45), median (range) follow-up (time from first dose to data cutoff) was 70.0 (66.2–88.7), 64.0 (60.0–75.8), and 52.4 (47.6–57.1) months (mo), respectively. ORR (95% CI) by INV was 39% (28–51), 65% (55–73), and 71% (56–84; Table) and progressive disease (PD) rates were 26%, 12%, and 16% in C1, C2, and C3, respectively. Median DOR was not reached in the 3 cohorts. The 48-mo PFS rates were 36%, 54%, and 51% and 48-mo OS rates were 49%, 71%, and 72% in C1, C2, and C3, respectively (Table). PFS and OS rates with up to 60 mo of follow-up will be presented. Safety data are shown in the table. Conclusions: With extended follow-up of ~5 years, NIVO ± IPI continued to demonstrate durable OS and PFS benefit, with no new safety signals. These updated data further support current treatment recommendations for 2L+ NIVO ± IPI and 1L NIVO + IPI for pts with MSI-H/dMMR mCRC. Clinical trial information: NCT02060188. [Table: see text]

269 Background: NIVO 1 mg/kg + IPI 3 mg/kg Q3W (4 doses) followed by NIVO 240 mg Q2W is approved in the US for sorafenib-treated pts with aHCC based on initial results from CheckMate 040 (NCT01658878), which reported objective response rate (ORR) of 32% and median overall survival (mOS) of 22.8 months (mo).1 We present 44-mo long-term follow-up results from the CheckMate 040 NIVO+IPI cohort. Methods: Pts were randomized to 3 arms: [A] NIVO 1 mg/kg + IPI 3 mg/kg Q3W (4 doses) or [B] NIVO 3 mg/kg + IPI 1 mg/kg Q3W (4 doses), each followed by NIVO 240 mg Q2W, or [C] NIVO 3 mg/kg Q2W + IPI 1 mg/kg Q6W. Treatment continued until intolerable toxicity or disease progression. Safety and tolerability, ORR (blinded independent central review per RECIST v1.1), duration of response (DOR), disease control rate (DCR), and OS were assessed. Data cutoff was May 26, 2020. Results: 148 pts were randomized. Minimum follow-up was 44 mo. mOS remained at 22.2 mo in arm A, 12.5 mo in arm B, and 12.7 mo in arm C; 36-mo OS rates were 42%, 26%, and 30%, respectively. Durable responses were achieved across treatment arms, with DOR approaching 4 years in some cases. DCR was higher in arm A than arms B and C. In all arms, responses were observed regardless of baseline programmed death ligand 1 expression ( < 1% or ≥ 1%) or baseline alpha-fetoprotein level ( < 400 µg/L or ≥ 400 µg/L). Pts with hepatitis B or C virus (HBV or HCV) etiology had higher ORR than uninfected pts in arms B (29% vs 43% vs 9%) and C (31% vs 42% vs 0%). ORR was independent of etiology in arm A (HBV, 32%; HCV, 29%; uninfected, 31%). Additional efficacy data are in the table. There were no additional discontinuations due to treatment-related adverse events or immune-mediated adverse events (IMAEs) since the primary analysis. IMAEs were reported more frequently in arm A than arms B and C; the most common were rash, hepatitis, and adrenal insufficiency. Most IMAEs were reversible and resolved when treated using established algorithms. Conclusions: At a minimum follow-up of 44 mo, second-line NIVO1+IPI3 continued to demonstrate clinically meaningful responses and long-term survival benefit in aHCC. The safety profile was manageable and no new safety signals were identified with longer follow-up. Clinical trial information: NCT01658878. [Table: see text]

O-3 Nivolumab (NIVO) plus chemotherapy (chemo) or ipilimumab (IPI) vs chemo as first-line treatment for advanced esophageal squamous cell carcinoma (ESCC): Expanded efficacy and safety analyses from CheckMate 648

9524 Background: NIVO + RELA as a fixed-dose combination (FDC) demonstrated a statistically significant progression-free survival (PFS) benefit vs NIVO in RELATIVITY-047 (NCT03470922), with a clinically meaningful, but not statistically significant, improvement in OS and a numerically higher objective response rate (ORR), resulting in regulatory approval of the FDC. Here we report updated descriptive analyses with 3 years of follow-up. Methods: Patients (pts) were randomized 1:1 to receive NIVO 480 mg + RELA 160 mg FDC or NIVO 480 mg Q4W. PFS per RECIST v1.1 was assessed by blinded independent central review (BICR); secondary endpoints included OS and ORR per BICR. Exploratory analyses included MSS (death due to melanoma, with censoring of deaths due to other causes), CNS metastasis-free survival in specified populations, and efficacy on subsequent systemic therapy. Results: At database lock (19 Oct 2023), median follow-up was 33.8 months (mo; range, 0.3–64.2). NIVO + RELA continued to show a benefit vs NIVO for PFS, OS, ORR, and MSS (Table). NIVO + RELA was also favored over NIVO across the majority of key subgroups. Subsequent systemic therapy was received by 135 pts (38%) on NIVO + RELA and 141 pts (39%) on NIVO. Grade 3–4 treatment-related adverse events (TRAEs) occurred in 78 pts (22%) on NIVO + RELA and 43 pts (12%) on NIVO; TRAEs (any grade) led to treatment discontinuation in 63 pts (18%) and 35 pts (10%), respectively. No new treatment-related deaths were reported since the last analysis. Conclusions: At 3 years of follow-up, NIVO + RELA continued to show a benefit vs NIVO for PFS, OS, ORR, and MSS. OS and MSS demonstrated sustained improvement, with the OS HR 95% CI upper bound < 1. Efficacy results also continued to favor NIVO + RELA vs NIVO across the majority of prespecified subgroups. Safety of NIVO + RELA remained consistent with previous reports, with no new or unexpected safety signals. CNS metastasis-free survival and efficacy outcomes on subsequent systemic therapy will be presented. Clinical trial information: NCT03470922 . [Table: see text]

549 Background: Intermediate-stage HCC, as defined as Barcelona Clinic Liver Cancer (BCLC) Stage B, is a heterogeneous disease in terms of liver function and tumor load. REACH (NCT01140347) and REACH-2 (NCT02435433) investigated ramucirumab (RAM) in patients (pts) with HCC after prior sorafenib (SOR), with REACH-2 enrolling only pts with baseline AFP ≥400 ng/mL. An exploratory analysis of outcomes by BCLC stage was performed. Methods: All pts had HCC (BCLC stage C or B disease refractory/not amenable to locoregional therapy), Child-Pugh A, ECOG PS 0-1, and prior SOR. Pts were randomized to RAM 8 mg/kg or Placebo (P) Q2W. A pooled meta-analysis of independent pt data (stratified by study) from REACH-2 and REACH (AFP ≥400 mg/mL) was performed. Prognosis of BCLC staging in overall survival (OS) was evaluated by multivariate Cox PH model (adjusted for baseline AFP and treatment (trt) arm); Trt effects in BCLC stage B and C by Cox PH model; median OS/PFS were estimated by Kaplan-Meier method. Objective response rate (ORR) per RECIST v1.1, disease control rate (DCR), and adverse events (AEs) were also reported by BCLC. Liver function was assessed at baseline and prior to each trt with the Albumin-Bilirubin (ALBI) linear predictor. Results: Baseline characteristics were generally balanced between trt arms in each BCLC stage. BCLC staging trended as an independent prognosis factor for OS [B v C; HR = 0.756 (0.546, 1.046)]. A consistent trt benefit for RAM v P was observed across staging (Table). Grade ≥3 AEs were consistent with observations from both individual studies; hypertension was the most frequent grade ≥3 AE. No difference in liver function, as measured by ALBI, was observed between trt arms in either BCLC stage. Conclusions: Acknowledging limitations of sample size, RAM provided a survival benefit irrespective of BCLC stage. RAM was well tolerated and did not alter liver function compared to P. Clinical trial information: NCT01140347, NCT02435433. [Table: see text]

4035 Background: NIVO + chemo and NIVO + IPI demonstrated significant overall survival (OS) benefit vs chemo in previously untreated patients (pts) with advanced ESCC in the phase 3 CheckMate 648 study. We report expanded results from the primary analysis with 13-month (mo) minimum follow-up. Methods: Pts with previously untreated, unresectable advanced, recurrent, or metastatic ESCC were randomized to NIVO (240 mg Q2W) + chemo (fluorouracil + cisplatin Q4W), NIVO (3 mg/kg Q2W) + IPI (1 mg/kg Q6W), or chemo. Primary endpoints were OS and progression-free survival (PFS) per blinded independent central review (BICR) in pts with tumor cell programmed death ligand 1 (PD-L1) ≥ 1%. Secondary endpoints planned for hierarchical testing included OS, PFS, and objective response rate (ORR) per BICR in all randomized pts. Duration of response (DOR) per BICR and PFS2 per investigator (time from randomization to progression after subsequent systemic therapy, initiation of second subsequent systemic therapy, or death) were exploratory endpoints. Results: Among all pts randomized to NIVO + chemo (n = 321), NIVO + IPI (n = 325), or chemo (n = 324), PFS2 favored NIVO + chemo (HR 0.64, 95% CI 0.54–0.77) and NIVO + IPI (HR 0.74, 95% CI 0.62–0.88) vs chemo. ORR (95% CI) was 47% (42–53), 28% (23–33), and 27% (22–32), respectively. More responders with NIVO + chemo or NIVO + IPI vs chemo had prolonged DOR (≥12 mo; 39%, 48%, and 23%, respectively). Efficacy data by tumor cell PD-L1 and PD-L1 combined positive score will be presented. Grade 3/4 treatment-related adverse events with potential immunologic etiology (select TRAEs) occurred in ≤ 6% of pts with NIVO + chemo and NIVO + IPI, and non-endocrine select TRAEs resolved in 57%–95% of pts across organ categories (Table). Conclusions: NIVO + chemo and NIVO + IPI demonstrated favorable PFS2 and a higher proportion of pts with prolonged DOR vs chemo, as well as acceptable safety profiles. These results provide further support for each regimen as a new potential 1L standard of care in advanced ESCC. Clinical trial information: NCT03143153. [Table: see text]

High tumor mutational burden assessed in tissue biopsies (tTMB-H) or blood (bTMB-H) is associated with clinical efficacy in patients treated with immunotherapies. CheckMate 848 (NCT03668119) is a prospective phase 2 study of nivolumab (NIVO) with or without ipilimumab (IPI) in patients with advanced or metastatic solid tumors that are tTMB-H or bTMB-H (≥ 10 mutations/megabase) who were immunotherapy-naive and refractory to standard local therapies. The primary endpoint was objective response rate (ORR) in patients with tTMB-H or bTMB-H, assessed by FoundationOne® CDx-based and Clinical Trial Assays (Foundation Medicine), respectively. The study was not powered to compare NIVO + IPI vs NIVO. We present the interim and final analyses for the tTMB-H and bTMB-H cohorts, respectively (≥ 12 months follow-up, database lock June 2021). Of 1954 screened patients, 212 were randomized 2:1 to NIVO 240 mg Q2W + IPI 1 mg/kg Q6W or NIVO 480 mg Q4W for ≤ 24 months, and 201 (135 tTMB-H; 147 bTMB-H) were refractory to standard therapies. Of > 40 tumor types, colorectal (10.8%), small-cell lung (7.5%), breast (7.1%), and uterine (7.1%) were the most common. ORR and survival outcomes with NIVO + IPI were improved in patients with tTMB-H. The responses were independent of bTMB-H status in the tTMB-H cohort but improved with tTMB-H status in the bTMB-H cohort (Table). The safety profile of NIVO + IPI was manageable, and clinical outcomes with NIVO were comparable with previous studies. The impact of TMB cutoff, PD-L1 expression, and microsatellite instability were explored. In conclusion, NIVO + IPI demonstrated clinical efficacy with a manageable safety profile in patients with advanced or metastatic solid tumors that are tTMB-H or bTMB-H and refractory to standard therapies, with increased efficacy observed in patients with tTMB-H. NIVO + IPI tTMB-H cohort bTMB-H cohorta Patients, n (%)b,c 68 (32.1) 80 (37.7) Number of prior treatments, median (range) 2 (0–7) 2 (1–9) ORR, n (%)c, 95% CI 24 (35.3), 24.1–47.8 18 (22.5), 13.9–33.2 ORR in patients with bTMB-H by tTMBc: < 10 mut/Mb (n = 31), n (%), 95% CI NA 3 (9.7), 2.0–25.8 ≥ 10 mut/Mb (n = 39), n (%), 95% CI NA 13 (33.3), 19.1–50.2 ≥ 10 to < 16 mut/Mb (n = 18), n (%), 95% CI NA 3 (16.7), 3.6–41.4 ≥ 16 mut/Mb (n = 21), n (%), 95% CI NA 10 (47.6), 25.7–70.2 ORR in patients with tTMB-H by bTMBc: < 10 mut/Mb (n = 20), n (%), 95% CI 7 (35.0), 15.4–59.2 NA ≥ 10 mut/Mb (n = 43), n (%), 95% CI 16 (37.2), 23.0–53.3 NA ≥ 10 to < 16 mut/Mb (n = 12), n (%), 95% CI 3 (25.0), 5.5–57.2 NA ≥ 16 mut/Mb (n = 31), n (%), 95% CI 13 (41.9), 24.5–60.9 NA Percentage of responders (≥ 9 months) (95% CI) 91 (68–98) 88 (61–97) Median PFS, months (95% CI)c 4.1 (2.8–11.3) 2.8 (2.3–3.0) Median OS, months (95% CI)c 14.5 (7.7–NE) 8.5 (5.8–10.5) aThe bTMB cohort was randomized prior to December 20, 2019. bOut of 212 randomized patients; data presented in this table are from patients who were refractory to standard therapies. cMinimum follow-up 12 months. bTMB, blood tumor mutational burden; NA, not applicable; NE, not evaluable; PFS, progression-free survival; OS, overall survival; tTMB, tissue tumor mutational burden. Citation Format: Michael Schenker, Mauricio Burotto, Martin Richardet, Tudor Ciuleanu, Anthony Goncalves, Neeltje Steeghs, Patrick Schöffski, Paolo A. Ascierto, Michele Maio, Iwona Lugowska, Lorena Lupinacci, Alexandra Leary, Jean-Pierre Delord, Julieta Grasselli, David S. Tan, Jennifer E. Friedmann, Jacqueline Vuky, Marina Tschaika, Ruta Slepetis, Georgia D. Kollia, Misena Pacius, Ning Huang, Parul Doshi, Jonathan Baden, Massimo Di Nicola. CheckMate 848: A randomized, open-label, phase 2 study of nivolumab in combination with ipilimumab or nivolumab monotherapy in patients with advanced or metastatic solid tumors of high tumor mutational burden [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT022.

3503 Background: NIVO + IPI demonstrated superior progression-free survival (PFS) vs chemo in patients (pts) with previously untreated MSI-H/dMMR mCRC in the randomized phase 3 CheckMate 8HW study (NCT04008030). We report expanded efficacy analysis from the prespecified interim analysis of NIVO + IPI vs chemo in the 1L setting. Methods: Pts with unresectable or mCRC and MSI-H/dMMR status by local testing were enrolled across different lines of therapy and randomized 2:2:1 to NIVO (240 mg) + IPI (1 mg/kg) Q3W (4 doses, then NIVO 480 mg Q4W), NIVO (240 mg) Q2W (6 doses, then NIVO 480 mg Q4W), or chemo ± targeted therapies; treatments continued until disease progression or unacceptable toxicity (all arms) or for up to 2 years (NIVO ± IPI arms). In pts with blinded independent central review (BICR)–documented progression with chemo, crossover to NIVO + IPI was permitted. Dual primary endpoints were PFS by BICR per RECIST v1.1 for NIVO + IPI vs chemo (1L) and NIVO + IPI vs NIVO (all lines) in pts with centrally confirmed MSI-H/dMMR mCRC. PFS2 (time from randomization to progression after subsequent systemic therapy, initiation of second subsequent systemic therapy, or death) was a key exploratory endpoint. Results: Among 303 pts randomized to NIVO + IPI (n = 202) or chemo (n = 101), 171 pts in the NIVO + IPI arm and 84 pts in the chemo arm had centrally confirmed MSI-H/dMMR. At 31.5-months (mo) median follow-up (range 6.1–48.4), NIVO + IPI demonstrated superior PFS vs chemo (HR 0.21; 97.91% CI 0.13–0.35; P < 0.0001). Subsequent systemic therapy was received by 20 (12%) and 57 (68%) pts in the NIVO + IPI and chemo arms, respectively. In the chemo arm, 56 (67%) pts received subsequent immunotherapy (39 [46%] crossed over to NIVO + IPI on study; 17 [20%] received non-study immunotherapy). Median PFS2 was not reached (NR) with NIVO + IPI and 29.9 mo with chemo (HR 0.27; 95% CI 0.17–0.44; Table). Any grade and grade 3/4 treatment-related adverse events (TRAEs) are presented (Table). Treatment-related deaths were reported for 2 pts in the NIVO + IPI arm. Conclusions: Clinical benefit with 1L NIVO + IPI vs chemo was maintained after subsequent therapy, as shown by improved PFS2 in pts with centrally confirmed MSI-H/dMMR mCRC. No new safety concerns were identified with NIVO + IPI. These results further support NIVO + IPI as a standard-of-care 1L treatment option for pts with MSI-H/dMMR mCRC. Clinical trial information: NCT04008030 . [Table: see text]

LBA768 Background: Patients (pts) with MSI-H/dMMR mCRC have poor outcomes with standard chemo ± targeted therapies. NIVO ± IPI are approved in previously treated pts with MSI-H/dMMR mCRC in many countries, based on the phase 2 CheckMate 142 study. CheckMate 8HW (NCT04008030) is a randomized phase 3 study comparing NIVO + IPI with NIVO or chemo in pts with MSI-H/dMMR mCRC. We report progression-free survival (PFS) by blinded independent central review (BICR) at a prespecified interim analysis for NIVO + IPI vs chemo in the 1L setting. Methods: Pts ≥ 18 years with recurrent or mCRC not amenable to surgery and MSI-H/dMMR status per local testing were enrolled across different lines of therapy. Previously untreated pts were randomized 2:2:1 to NIVO (240 mg) + IPI (1 mg/kg) Q3W (4 doses, then NIVO 480 mg Q4W), NIVO (240 mg) Q2W (6 doses, then NIVO 480 mg Q4W), or chemo ± targeted therapies; treatments continued until disease progression or unacceptable toxicity (all arms), or a maximum of 2 years (NIVO ± IPI arms). For pts with BICR-documented progression with chemo, optional crossover to NIVO + IPI was permitted. Dual primary endpoints were PFS by BICR per RECIST v1.1 for NIVO + IPI vs chemo (1L) and NIVO + IPI vs NIVO (all lines) in pts with centrally confirmed MSI-H/dMMR mCRC. Results: In the 1L setting, 303 pts were randomized to NIVO + IPI (n = 202) or chemo (n = 101); of these pts, 171 pts in the NIVO + IPI arm and 84 pts in the chemo arm had centrally confirmed MSI-H/dMMR result by either immunohistochemistry and/or polymerase chain reaction-based tests. With 24.3 months of median follow-up, NIVO + IPI demonstrated clinically meaningful and statistically significant improvement in PFS vs chemo, with a 79% reduction in the risk of disease progression or death (HR 0.21 [95% CI 0.14–0.32]; P < 0.0001) (Table). No new safety signals were identified (Table). Conclusions: NIVO + IPI demonstrated superior PFS vs chemo in previously untreated pts with MSI-H/dMMR mCRC. NIVO + IPI had a different safety profile compared to chemo, with fewer grade 3–4 treatment-related adverse events (TRAEs). These results support 1L NIVO + IPI as a standard-of-care option for pts with MSI-H/dMMR mCRC. Clinical trial information: NCT04008030 . [Table: see text]