Nivolumab (NIVO) plus ipilimumab (IPI) vs chemotherapy (chemo) as first-line (1L) treatment for microsatellite instability-high/mismatch repair-deficient (MSI-H/dMMR) metastatic colorectal cancer (mCRC): Expanded efficacy analysis from CheckMate 8HW.

3501 Background: In the phase 3 CheckMate 8HW study (NCT04008030), both dual primary endpoints of progression-free survival (PFS) for first-line (1L) NIVO + IPI vs chemo (HR 0.21; P < 0.0001) and NIVO + IPI vs NIVO across all lines (HR 0.62; P = 0.0003) in patients (pts) with centrally confirmed MSI-H/dMMR mCRC were met. We report expanded analyses of NIVO + IPI vs NIVO (all lines) and longer follow-up results for NIVO + IPI vs chemo (1L). Methods: The study design was described previously. Pts with MSI-H/dMMR per local testing were enrolled. After randomization, IHC and PCR based tests were used for central confirmation. PFS2 (time from randomization to progression after subsequent systemic therapy, start of second subsequent systemic therapy, or death) was a key exploratory endpoint. Results: In all randomized pts (all lines), 296 of 354 (84%) in the NIVO + IPI arm, 286 of 353 (81%) in the NIVO arm, and 113 of 132 (86%) in the chemo arm had centrally confirmed MSI-H/dMMR. In all randomized 1L pts, 171 of 202 (85%) in the NIVO + IPI arm and 84 of 101 (83%) in the chemo arm had centrally confirmed MSI-H/dMMR. Median follow-up was 47.0 mo (range 16.7–60.5). 1L NIVO + IPI continued to show PFS benefit vs chemo (Table). Subsequent systemic therapy was received by 27 (16%) and 61 (73%) pts after 1L NIVO + IPI and chemo, respectively; 10 (6%) and 21 (25%) received subsequent non-study immunotherapy. In the 1L chemo arm, 39 (46%) pts crossed over to NIVO + IPI on study. PFS2 continued to favor 1L NIVO + IPI vs chemo (Table). Across all lines, NIVO + IPI demonstrated superior PFS vs NIVO (Table). Subsequent systemic therapy was received by 54 (18%) pts in the NIVO + IPI arm and 83 (29%) in the NIVO arm; 20 (7%) and 31 (11%) received subsequent non-study immunotherapy. PFS2 favored NIVO + IPI vs NIVO across all lines of therapy (Table). In all treated pts, grade 3/4 treatment-related adverse events occurred in 78 (22%) and 50 (14%) pts in the NIVO + IPI and NIVO arms, respectively. Additional analyses will be presented. Conclusions: NIVO + IPI demonstrated sustained clinical benefit vs chemo (1L) and NIVO (all lines) despite use of subsequent therapy, as shown by improved PFS2 in pts with centrally confirmed MSI-H/dMMR mCRC. No new safety signals were observed. These results support NIVO + IPI as a standard of care treatment for MSI-H/dMMR mCRC. Clinical trial information: NCT04008030 . Centrally confirmed MSI-H/dMMR (1L) NIVO + IPI(n = 171) Chemo(n = 84) Median PFS (95% CI), mo 54.1 (54.1–NE) 5.9 (4.4–7.8) HR (95% CI) 0.21 (0.14–0.31) Median PFS2 (95% CI), mo NR (NE–NE) 30.3 (15.2–NE) HR (95% CI) 0.28 (0.18–0.44) Centrally confirmed MSI-H/dMMR (all lines) NIVO + IPI (n = 296) NIVO (n = 286) Median PFS (95% CI), mo NR (53.8–NE) 39.3 (22.1–NE) HR (95% CI) 0.62 (0.48-0.81); P = 0.0003 Median PFS2 (95% CI), mo NR (NE–NE) NR (NE–NE) HR (95% CI) 0.57 (0.42–0.78) NE, not evaluable; NR, not reached.

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]

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.

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]

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

9502 Background: In RELATIVITY-047 (NCT03470922), NIVO + RELA demonstrated a statistically significant progression-free survival (PFS) benefit vs NIVO; there was an observed improvement in overall survival (OS) although it was not statistically significant. The combination also had a descriptively higher confirmed objective response rate (ORR) assessed by blinded independent central review (BICR) vs NIVO. Here we report updated descriptive analyses (efficacy, safety, and secondary analyses) with longer (~ 2 years) follow-up. Methods: Patients were randomized 1:1 to receive NIVO 480 mg + RELA 160 mg fixed-dose combination or NIVO 480 mg every 4 weeks, as previously described. Primary endpoint of PFS per RECIST v1.1 was assessed by BICR; secondary endpoints included OS and ORR per BICR. Exploratory analyses were performed for melanoma-specific survival (MSS; defined as death due to melanoma, with censoring of deaths due to other causes) and efficacy outcomes on subsequent systemic therapy. Results: Patients received NIVO + RELA (n = 355) or NIVO (n = 359). Median follow-up was 25.3 months in this updated analysis (minimum follow-up, 21.0 months). NIVO + RELA continued to show a benefit over NIVO for PFS, OS and ORR (Table). A similar improvement was also observed in MSS. NIVO + RELA was generally favored over NIVO across key subgroups (consistent with previous reports). Subsequent systemic therapy was received by 131 (36.9%) and 136 (37.9%) patients in the NIVO + RELA and NIVO arms, respectively. Treatment-related adverse events (TRAEs; any grade) leading to treatment discontinuation were observed in 61 (17.2%) and 31 (8.6%) patients on NIVO + RELA and NIVO, respectively. Grade 3–4 TRAEs were observed in 78 (22.0%) patients on NIVO + RELA and 43 (12.0%) patients on NIVO. In total, there were 6 treatment-related deaths (NIVO + RELA, n = 4; NIVO, n = 2); no new treatment-related deaths have been reported since the last analysis. Conclusions: With 12.3 months of additional follow-up, a consistent benefit was observed with NIVO + RELA vs NIVO for PFS, OS and ORR in the ITT population, as well as in key patient subgroups. MSS was longer with NIVO + RELA compared with NIVO. The safety profile of NIVO + RELA remained consistent with previous reports, with no new or unexpected safety signals. Efficacy outcomes on subsequent systemic therapy (by type of subsequent therapy, including PD-L1/CTLA-4) will be presented. Clinical trial information: NCT03470922 . [Table: see text]

9506 Background: In the phase 3 CheckMate 067 trial, a durable and sustained clinical benefit was achieved with nivolumab (NIVO) + ipilimumab (IPI) and NIVO alone vs IPI at 5-y of follow-up (overall survival [OS] and progression-free survival [PFS] rates: 52%, 44%, 26% and 36%, 29%, 8%, respectively). Here we report 6.5-y efficacy and safety outcomes. Methods: Eligible pts with previously untreated unresectable stage III or IV melanoma were randomly assigned in a 1:1:1 ratio and stratified by PD-L1 status, BRAF mutation status, and metastasis stage. Pts received NIVO 1 mg/kg + IPI 3 mg/kg for 4 doses Q3W followed by NIVO 3 mg/kg Q2W (n = 314), NIVO 3 mg/kg Q2W + placebo (n = 316), or IPI 3 mg/kg Q3W for 4 doses + placebo (n = 315) until progression or unacceptable toxicity. Co-primary endpoints were PFS and OS with NIVO + IPI or NIVO vs IPI. Secondary endpoints included objective response rate (ORR), descriptive efficacy assessments of NIVO + IPI vs NIVO alone, and safety. Results: With a minimum follow-up of 6.5 y, median OS was 72.1 mo with NIVO + IPI, 36.9 mo with NIVO, and 19.9 mo with IPI (table). Median time from randomization to subsequent systemic therapy was not reached (NR; 95% CI, 59.6–NR) with NIVO + IPI, 25.2 mo (95% CI, 16.0–43.2) with NIVO, and 8.0 mo (95% CI, 6.5–8.7) with IPI; 36%, 49%, and 66% of pts, respectively, received any subsequent systemic therapy. Median treatment-free interval (which excluded pts who discontinued follow-up prior to initiation of subsequent systemic therapy) was 27.6 mo (range, 0–83.0), 2.3 mo (range, 0.2–81.6), and 1.9 mo (range, 0.1–81.9) with NIVO + IPI, NIVO, and IPI, respectively. Of the pts alive and in follow-up, 112/138 (81%; NIVO + IPI), 84/114 (74%; NIVO), and 27/63 (43%; IPI) were off treatment and never received subsequent systemic therapy; 7, 8, and 0 pts, respectively, were still on treatment. Grade 3/4 treatment-related adverse events were reported in 59% of NIVO + IPI-treated pts, 24% of NIVO-treated pts, and 28% of IPI-treated pts. Since the 5-y analysis, no new safety signals were observed and no additional treatment-related deaths occurred. Conclusions: This 6.5-y analysis represents the longest follow-up from a phase 3 melanoma trial in the modern checkpoint inhibitor combination therapy and targeted therapy era. The results show durable improved outcomes with NIVO + IPI and NIVO vs IPI in pts with advanced melanoma. We observed improvement in OS, PFS, and ORR with NIVO + IPI over NIVO alone. Clinical trial information: NCT01844505. [Table: see text]

9522 Background: Durable clinical benefit has been achieved with nivolumab (NIVO) + ipilimumab (IPI), including an overall survival (OS) of 49% and a melanoma-specific survival (MSS) of 56%, with median MSS not reached (NR) at 6.5-y minimum follow-up. Here we report sustained efficacy outcomes at 7.5 y. Methods: Patients (pts) with previously untreated, unresectable stage III/IV melanoma were randomly assigned 1:1:1 and stratified by PD-L1 status, BRAF mutation status, and metastasis stage to receive NIVO 1 mg/kg + IPI 3 mg/kg for 4 doses Q3W, followed by NIVO 3 mg/kg Q2W (n = 314); NIVO 3 mg/kg Q2W + placebo (n = 316); or IPI 3 mg/kg Q3W for 4 doses + placebo (n = 315) until progression or unacceptable toxicity. Co-primary endpoints were progression-free survival (PFS) and OS with NIVO + IPI or NIVO alone versus IPI. Results: With a minimum follow-up of 7.5 y, median OS remained stable at 72.1 mo (NIVO + IPI), 36.9 mo (NIVO), and 19.9 mo (IPI); median MSS was NR, 49.4 mo, and 21.9 mo, respectively (Table). While the objective response rate remained stable at 58% (NIVO + IPI), 45% (NIVO), and 19% (IPI), median duration of response had now been reached for NIVO at 90.8 mo and remains NR and 19.2 mo for NIVO + IPI and IPI, respectively. Subsequent systemic therapy was received by 36%, 49%, and 66% of NIVO + IPI-, NIVO-, and IPI-treated patients, respectively, and median time to that therapy was NR (95% CI, 45.9–NR), 24.7 mo (16.0–38.7), and 8.0 mo (6.5–8.7). Of patients alive at 7.5 y, 106/138 (77%, NIVO + IPI), 80/115 (70%, NIVO), and 27/60 (45%, IPI) were off treatment and had never received subsequent systemic therapy. No change to the safety summary was observed with additional follow-up; updated health-related quality of life data will be reported. Of the 10 new deaths since the 6.5-y follow-up (ie, 5 NIVO + IPI; 3 NIVO; 2 IPI), none were treatment-related; 4 were due to melanoma progression; 1 was due to an unknown cause; and 5 were due to other causes, but not associated with a COVID diagnosis. Conclusions: The 7.5-y follow-up continues to demonstrate the durability of responses with NIVO + IPI and an ongoing survival plateau. A substantial difference in median OS and MSS between patients treated with NIVO + IPI or NIVO was observed in descriptive analyses. Clinical trial information: NCT04540705. [Table: see text]

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]

LBA4001 Background: NIVO demonstrated superior overall survival (OS) vs chemo in previously treated patients (pts) with ESCC (ATTRACTION-3). We report OS and progression-free survival (PFS) from CheckMate 648, the first global phase III study to evaluate both an immuno-oncology (I-O)/chemo combination and an I-O/I-O combination in advanced ESCC. Methods: Adults with previously untreated, unresectable advanced, recurrent or metastatic ESCC were enrolled regardless of tumor cell PD-L1 expression. Pts were randomized to NIVO (240 mg Q2W) + chemo (fluorouracil + cisplatin Q4W), NIVO (3 mg/kg Q2W) + IPI (1 mg/kg Q6W), or chemo alone. Primary endpoints for both comparisons were OS and PFS per blinded independent central review (BICR) in pts with tumor cell PD-L1 ≥ 1%. Hierarchically tested secondary endpoints included OS and PFS in all randomized pts. Results: 970 pts were randomized to NIVO + chemo, NIVO + IPI, and chemo arms (49% with tumor cell PD-L1 ≥ 1%). With 13 months (mo) minimum follow-up, NIVO + chemo and NIVO + IPI led to statistically significant improvement in OS vs chemo in pts with tumor cell PD-L1 ≥ 1% and all randomized pts (Table). Statistically significant PFS benefit was also observed for NIVO + chemo vs chemo (HR 0.65 [98.5% CI 0.46–0.92]; P = 0.0023) in pts with tumor cell PD-L1 ≥ 1%. PFS in NIVO + IPI vs chemo in pts with tumor cell PD-L1 ≥ 1% did not meet the prespecified boundary for significance. The objective response rate (per BICR) was 53% (NIVO + chemo), 35% (NIVO + IPI), and 20% (chemo) in pts with tumor cell PD-L1 ≥ 1% and in all randomized pts was 47%, 28%, and 27%, respectively; longer median (95% CI) duration of response was observed vs chemo for pts with tumor cell PD-L1 ≥ 1%: 8.4 (6.9–12.4), 11.8 (7.1–27.4), and 5.7 (4.4–8.7) mo and for all randomized pts: 8.2 (6.9–9.7), 11.1 (8.3–14.0), and 7.1 (5.7–8.2) mo, respectively. No new safety signals were identified (Table). Conclusions: NIVO plus chemo and NIVO plus IPI both demonstrated superior OS vs chemo, along with durable objective responses and acceptable safety, in pts with advanced ESCC, and each represents a potential new 1L treatment option. Clinical trial information: NCT03143153. [Table: see text]

9000 Background: In the randomized phase 3 CheckMate 9LA trial (NCT03215706), first-line NIVO + IPI combined with 2 cycles of chemo significantly improved overall survival (OS), progression-free survival (PFS), and objective response rate (ORR) vs chemo alone (4 cycles). Clinical benefit was observed regardless of programmed death ligand 1 (PD-L1) expression level and histology. Here we report data with 2 years’ minimum follow-up from this study. Methods: Adult patients (pts) with stage IV / recurrent NSCLC, ECOG performance status ≤ 1, and no known sensitizing EGFR/ALK alterations were stratified by PD-L1 (< 1% vs ≥ 1%), sex, and histology (squamous vs non-squamous) and were randomized 1:1 to NIVO 360 mg Q3W + IPI 1 mg/kg Q6W + chemo (2 cycles; n = 361) or chemo alone (4 cycles; n = 358). Pts with non-squamous NSCLC in the chemo-alone arm could receive pemetrexed maintenance. The primary endpoint was OS. Secondary endpoints included PFS and ORR by blinded independent central review, and efficacy by different PD-L1 levels. Safety was exploratory. Results: At a minimum follow-up of 24.4 months for OS (database lock: Feb 18, 2021), pts treated with NIVO + IPI + chemo continued to derive OS benefit vs chemo, with a median OS of 15.8 months vs 11.0 months, respectively (HR, 0.72 [95% CI, 0.61–0.86]); 2-year OS rates were 38% vs 26%. Median PFS with NIVO + IPI + chemo vs chemo was 6.7 months vs 5.3 months (HR, 0.67 [95% CI, 0.56–0.79]); 8% and 37% of pts who had disease progression received subsequent immunotherapy, respectively. ORR was 38% with NIVO + IPI + chemo vs 25% with chemo. Similar clinical benefit with NIVO + IPI + chemo vs chemo was observed in all randomized pts and across the majority of subgroups, including by PD-L1 expression level (Table) or histology. Any grade and grade 3–4 treatment-related adverse events were reported in 92% and 48% of pts in the NIVO + IPI + chemo arm vs 88% and 38% in the chemo arm, respectively. Conclusion: With 2 years’ minimum follow-up, first-line NIVO + IPI + chemo demonstrated durable survival and benefit versus chemo in pts with advanced NSCLC; no new safety signals were identified. Clinical trial information: NCT03215706. [Table: see text]

240 Background: CheckMate 649 is a randomized, global phase 3 study of 1L programmed death-1 (PD-1) inhibitor–based therapies in advanced non-HER2-positive GC/GEJC/EAC that demonstrated superior overall survival (OS) with NIVO + chemo vs chemo, leading to approvals in the US and other countries. Clinically meaningful long-term survival benefit with NIVO + chemo vs chemo was observed with 24 months (mo) of minimum follow-up in all randomized patients (pts) for both OS (HR 0.79 [95% CI 0.71–0.88]) and progression-free survival (PFS; HR 0.79 [95% CI 0.70–0.89]; Janjigian YY et al; ESMO 2021). We present expanded analyses of NIVO + chemo vs chemo with minimum follow-up of 24 mo. Methods: Adults with previously untreated, unresectable advanced or metastatic GC/GEJC/EAC were enrolled regardless of PD-ligand (L)1 expression. Pts with known HER2-positive status were excluded. Pts were randomized to NIVO (360 mg Q3W or 240 mg Q2W) + chemo (XELOX Q3W or FOLFOX Q2W), NIVO 1 mg/kg + IPI 3 mg/kg Q3W (4 doses, then NIVO 240 mg Q2W), or chemo. Dual primary endpoints were OS and PFS (per blinded independent central review) in pts with PD-L1 combined positive score (CPS) ≥ 5 for NIVO + chemo vs chemo. Hierarchically tested secondary endpoints included OS in NIVO + chemo vs chemo (PD-L1 CPS ≥ 1, then all randomized). Results: Of 2031 pts, 1581 were randomized to NIVO + chemo or chemo. In all randomized pts, 41% of pts (NIVO + chemo) and 44% of pts (chemo) received subsequent therapy. Median PFS2 (time from randomization to progression after subsequent systemic therapy, initiation of second subsequent systemic therapy, or death, whichever is earlier) was 12.2 (95% CI 11.3–13.5) mo with NIVO + chemo and 10.4 (95% CI 9.7–11.2) mo with chemo (HR 0.75 [95% CI 0.67–0.84]). 51% of pts (NIVO + chemo) and 43% of pts (chemo) had > 50% reduction from baseline in tumor burden, while 24% and 17% had > 80% reduction, respectively. The HR (95% CI) for OS was 0.66 (0.56–0.77) among pts with a PD-L1 CPS ≥ 10 (median OS for NIVO + chemo vs chemo: 15.0 [95% CI 13.7–16.7] vs 10.9 [95% CI 9.8–11.9] mo). OS benefit was observed with NIVO + chemo vs chemo across multiple additional subgroups, and these data will be presented. No new safety signals were identified. The majority of the treatment-related adverse events with potential immunologic etiology were grade 1 or 2 and grade 3 or 4 events were reported in ≤ 5% of pts in both treatment arms. Conclusions: NIVO + chemo continued to demonstrate clinically meaningful efficacy and an acceptable safety profile with longer follow-up, further supporting the use of NIVO + chemo as a standard 1L therapy in previously untreated pts with advanced GC/GEJC/EAC. Clinical trial information: NCT02872116.

9506 Background: MCC is a rare and aggressive skin cancer. Programmed death-ligand 1 (PD-L1) is often upregulated in MCC and blockade of PD-L1 or its receptor, PD-1, has improved survival for patients with metastatic MCC. Anti–PD-1 combined with anti–CTLA-4 has been reported to improve outcomes over anti–PD-1 monotherapy (NCT03071406; Kim S et al., Lancet 2022), however further investigation is needed. CheckMate 358 (NCT02488759) assessed NIVO ± IPI in 2 non-randomized MCC cohorts. Methods: Eligible pts had recurrent or metastatic MCC, ≤ 2 prior therapies, ECOG performance status (PS) 0–1, and no prior immune checkpoint inhibitor (ICI) therapy. Pts were eligible regardless of PD-(L)1 status. Pts received NIVO 240 mg Q2W or NIVO 3 mg/kg Q2W + IPI 1 mg/kg Q6W for ≤ 24 months (m) or until disease progression, unacceptable toxicity, or consent withdrawal. Imaging was conducted Q8W in year 1 and Q12W thereafter. Planned sample sizes were 23 pts for NIVO and 40 pts for NIVO + IPI. The primary endpoint was investigator-assessed objective response rate (ORR). Secondary endpoints included duration of response (DOR), investigator-assessed progression-free survival (PFS), and overall survival (OS). Results: 68 pts received NIVO (n = 25) or NIVO + IPI (n = 43) with ≥ 24 m follow-up (median: NIVO, 62.5 m; NIVO + IPI, 24.4 m). In the NIVO arm, median age was 66 yrs (range, 27–88), 10 (40.0%) pts had ECOG PS of 1, and 15 (60.0%) were treatment-naive. In the NIVO + IPI arm, median age was 70 yrs (range, 48–85), 27 (62.8%) pts had ECOG PS of 1, and 33 (76.7%) were treatment-naive. Treatment duration was 15.8 m in the NIVO arm, and 7.9 m for NIVO and 6.0 m for IPI in the NIVO + IPI arm. Efficacy and safety outcomes are summarized in the table. ORR was 60.0% (95% CI, 38.7–78.9) in the NIVO arm and 58.1% (95% CI, 42.1–73.0) in the NIVO + IPI arm. The most common reasons for treatment discontinuation were disease progression (NIVO, 28.0%; NIVO + IPI, 32.6%) or study-drug toxicity (NIVO, 20.0%; NIVO + IPI, 25.6%). There was 1 study drug-related death in each arm (NIVO, pneumonitis; NIVO + IPI, gastrointestinal motility disorder). Conclusions: Both NIVO and NIVO + IPI show durable clinical efficacy in advanced MCC. While the non-randomized trial design limits comparisons between the arms, results do not suggest additional efficacy benefit with IPI added to NIVO. Higher incidence of grade 3/4 TRAEs observed in the combination arm could have resulted in shorter treatment duration. Clinical trial information: NCT02488759 . [Table: see text]

LBA9025 Background: In CheckMate 227 part 1 (NCT02477826), 1L NIVO + IPI demonstrated long-term, durable survival benefit vs platinum-doublet chemo in patients (pts) with metastatic NSCLC regardless of tumor programmed death ligand 1 (PD-L1) expression level. Here we present the longest reported follow-up (5 y) of a phase 3 trial of 1L combination immunotherapy in metastatic NSCLC. Methods: Adults with previously untreated stage IV or recurrent NSCLC, no known EGFR/ ALK alterations , and an ECOG performance status ≤ 1 were enrolled and stratified by histology. Pts with tumor PD-L1 ≥ 1% were randomized 1:1:1 to NIVO (3 mg/kg Q2W) + IPI (1 mg/kg Q6W), NIVO (240 mg Q2W), or chemo. Pts with tumor PD-L1 < 1% were randomized 1:1:1 to NIVO + IPI, NIVO (360 mg Q3W) + chemo, or chemo. Pts were treated until progression, toxicity, or ≤ 2 y for immunotherapy. Assessments included overall survival (OS), progression-free survival (PFS), objective response rate (ORR), duration of response (DOR), and a novel efficacy endpoint, treatment-free interval. Treatment-free interval was measured in pts who discontinued study therapy (for any reason including treatment completion) and was defined as the time from last study dose to start of subsequent systemic therapy or death, whichever occurred first. Results: Minimum follow-up was 61.3 mo (database lock, Feb 15, 2022). In pts with tumor PD-L1 ≥ 1% (N = 1189), continued long-term OS benefit was seen with NIVO + IPI vs chemo (HR, 0.77 [95% CI, 0.66–0.91]); 5-y OS rates were 24% (NIVO + IPI), 17% (NIVO), and 14% (chemo). OS benefit also continued in pts with tumor PD-L1 < 1% (N = 550) for NIVO + IPI vs chemo (HR, 0.65 [95% CI, 0.52–0.81]); 5-y OS rates were 19% (NIVO + IPI), 10% (NIVO + chemo), and 7% (chemo). Clinical benefit with NIVO + IPI vs chemo was observed across additional efficacy endpoints in the overall population and in pts alive at 5 y (table). PFS, ORR, and DOR with NIVO and NIVO + chemo will be presented. Among pts alive at 5 y in the NIVO + IPI group, 66% (PD-L1 ≥ 1%) and 64% (PD-L1 < 1%) remained treatment-free ≥ 3 y after discontinuing study therapy; median (range) duration of NIVO ± IPI therapy was 17.7 (0-25.5) mo (PD-L1 ≥ 1%) and 9.5 (0-25.1) mo (PD-L1 < 1%). No new safety signals were observed. Conclusions: With a 5-y minimum follow-up, NIVO + IPI continues to provide long-term, durable clinical benefit vs chemo in previously untreated pts with metastatic NSCLC, regardless of PD-L1 expression. NIVO + IPI led to increased 5-y survivorship; the majority of these pts were treatment-free for ≥ 3 y post-treatment discontinuation. Clinical trial information: NCT02477826. [Table: see text]

9501 Background: NIVO + IPI was shown to improve overall survival (OS) and durability of response vs chemo in 1L advanced NSCLC in CheckMate 227 Part 1, regardless of PD-L1 expression. We hypothesized that a limited course of chemo combined with NIVO + IPI could provide rapid disease control while building on the durable OS benefit seen with dual PD-1 and CTLA-4 inhibition. CheckMate 9LA (NCT03215706) is a phase 3 randomized study evaluating NIVO + IPI + 2 cycles chemo vs chemo in 1L stage IV/recurrent NSCLC. Methods: Adults with tx-naive, histologically confirmed stage IV/recurrent NSCLC, ECOG performance status 0–1, and no known sensitizing EGFR/ALK alterations were randomized 1:1 to NIVO 360 mg Q3W + IPI 1 mg/kg Q6W + chemo (2 cycles) (n = 361) or chemo (4 cycles) alone (n = 358), stratified by PD-L1 (< 1% vs ≥ 1%), sex, and histology (squamous vs non-squamous). Chemo was based on histology. Pts with non-squamous NSCLC in the chemo-only arm could receive optional pemetrexed maintenance. Pts were treated with immunotherapy until disease progression, unacceptable toxicity, or for 2 y. The primary endpoint was OS; the interim analysis using Lan–DeMets alpha spending function with O’Brien–Fleming boundary was planned at ~80% information fraction (ie, after observing ~322 total events). Secondary endpoints included progression-free survival (PFS) and objective response rate (ORR) by blinded independent central review, and efficacy by PD-L1 subgroups. Exploratory endpoints included safety/tolerability. Results: Baseline characteristics were balanced across arms. At a preplanned interim analysis (minimum follow-up 8.1 mo), OS was significantly prolonged with NIVO + IPI + chemo vs chemo (HR 0.69, 96.71% CI: 0.55–0.87; P = 0.0006); statistically significant improvements in PFS and ORR were seen. With longer follow-up (minimum 12.7 mo), NIVO + IPI + chemo vs chemo continued to provide longer OS; median 15.6 vs 10.9 mo (HR 0.66, 95% CI: 0.55–0.80); 1-y OS rates were 63 vs 47%. Clinical benefit was consistent across all efficacy measures in key subgroups including by PD-L1 and histology. Grade 3–4 tx-related adverse events were reported in 47 vs 38% of pts in the NIVO + IPI + chemo vs chemo arms, respectively. Conclusions: CheckMate 9LA met its primary endpoint: a statistically significant improvement in OS was observed with NIVO + NSCLC-optimized IPI + a limited course of chemo vs chemo (4 cycles) in 1L advanced NSCLC. No new safety signals were reported. Clinical trial information: NCT03215706 .