First results of nivolumab (NIVO) plus ipilimumab (IPI) vs NIVO monotherapy for microsatellite instability-high/mismatch repair-deficient (MSI-H/dMMR) metastatic colorectal cancer (mCRC) from CheckMate 8HW.

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]

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]

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.

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]

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 .

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

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]

P-12 A phase 3 study of nivolumab (NIVO), NIVO + ipilimumab (IPI), or chemotherapy for microsatellite instability-high (MSI-H)/mismatch repair-deficient (dMMR) metastatic colorectal cancer (mCRC): CheckMate 8HW

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]

9542 Background: NIVO + IPI has demonstrated durable clinical benefit at 7.5 y in pts with advanced melanoma in the phase 3 CheckMate 067 study. PFS curves plateaued at ~3 y in this study, suggesting that being alive and progression-free for ≥ 3 y (PFS ≥ 3y) may be a good surrogate for long-term clinical benefit. We conducted analyses to quantify this association. Methods: Pts with treatment (tx)-naive, unresectable stage III/IV melanoma (stratified by PD-L1 expression, BRAF mutation status, and metastasis stage) 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. Exploratory post hoc analysis was performed in pts with PFS ≥ 3y. Results: In the NIVO + IPI, NIVO, and IPI arms, respectively, 99 (32%), 78 (25%), and 21 (7%) pts had PFS ≥ 3y. Objective response rates (ORRs) in these pts were ≥ 95% (table). The majority of responses were complete responses (CRs; table); in almost all pts with partial responses (PRs) on NIVO + IPI or NIVO, target-lesion size decreased by ≥ 50%. At 7.5 y of follow-up among pts alive and progression-free at 3 y, PFS rates were ≥ 68%, overall survival (OS) rates were ≥ 85%, and melanoma-specific survival (MSS) rates were ≥ 95% in the 3 tx groups (table). Among pts in this group who died after 3 y on study, the majority of deaths were unrelated to disease (table). The majority of pts with PFS ≥ 3y who were alive and in follow-up were tx-free at the 7.5-y data cutoff (77/84, 57/64, and 13/16). Pts who received NIVO + IPI were off tx (median) for 75.5 mo (NIVO, 55.7 mo; IPI, 59.2 mo). Among pts with PFS ≥ 3y in the 3 tx groups, 4%, 5%, and 19% received subsequent systemic tx (table). No new safety signals were observed in pts with PFS ≥ 3y. Conclusions: This exploratory post hoc analysis suggested that PFS ≥ 3y may be a good surrogate for long-term MSS with NIVO + IPI or NIVO, with very few occurrences of progression or death due to melanoma in this population through 7.5 y. Most pts were tx-free without having received subsequent systemic tx after demonstrating PFS ≥ 3y. Further study of pts with PFS ≥ 3y may allow the burden of imaging and follow-up visits to be reduced in this group. Clinical trial information: NCT01844505 . [Table: see text]

LBA1 Background: The results of a phase I study in MEL suggested complementary clinical activity with NIVO (a PD-1 checkpoint inhibitor) plus IPI (a CTLA-4 checkpoint inhibitor). Here, we report the results of a randomized, double-blind, phase III trial designed to evaluate NIVO combined with IPI or NIVO alone vs IPI alone in MEL. Methods: Treatment-naïve pts (N = 945) were randomized 1:1:1 to NIVO 1 mg/kg Q2W + IPI 3 mg/kg Q3W for 4 doses followed by NIVO 3 mg/kg Q2W, NIVO 3 mg/kg Q2W + placebo, or IPI 3 mg/kg Q3W for 4 doses + placebo, until progression or unacceptable toxicity. Pts were stratified by PD-L1 status, BRAF mutation status, and M-stage. Co-primary endpoints are progression-free survival (PFS) (reported here) and overall survival (pts continue to be followed). Secondary endpoints include objective response rate (ORR) by RECIST v1.1 and safety. Results: At a minimum follow-up of 9 months, NIVO + IPI and NIVO alone significantly improved PFS and ORR vs IPI (Table). Grade 3-4 drug-related adverse events (AEs) occurred in 55.0%, 16.3%, and 27.3% of pts in the NIVO + IPI, NIVO, and IPI arms, respectively (most commonly diarrhea [9.3%, 2.2%, 6.1%], increased lipase [8.6%, 3.5%, 3.9%], increased alanine aminotransferase [8.3%, 1.3%, 1.6%], and colitis [7.7%, 0.6%, 8.7%]). Drug-related AEs led to discontinuation in 36.4%, 7.7%, and 14.8% of pts in the NIVO + IPI, NIVO, and IPI arms, with 0, 1, and 1 drug-related deaths, respectively. Efficacy outcomes by PD-L1 status will also be presented. Conclusions: NIVO + IPI and NIVO alone had superior clinical activity vs IPI alone. The results with NIVO + IPI and NIVO alone further suggest complementary activity of the two agents. There were no new safety signals or drug-related deaths observed with the combination. Clinical trial information: NCT01844505. [Table: see text]

512 Background: NIVO monotherapy is approved in the United States and other countries for pts with HCC treated with sorafenib (SOR) based on CheckMate 040 (NCT01658878) results, which reported 14% objective response rate (ORR) and 16-month median overall survival (mOS; El-Khoueiry et al. Lancet 2017). Primary efficacy and safety of NIVO + IPI in pts with aHCC previously treated with SOR were presented recently (Yau et al. J Clin Oncol 2019). Here, we will present subgroup analyses from this study. 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/tolerability, ORR, and duration of response (DOR; investigator assessment per RECIST v1.1). Key secondary endpoints included disease control rate (DCR), OS, and progression-free survival (blinded independent central review [BICR] per RECIST v1.1); key exploratory endpoints included ORR (BICR per RECIST v1.1). Data cutoff was January 2019. Results: A total of 148 pts were randomized. Minimum OS follow-up from last pt randomization date to data cutoff was 28 months. At baseline, 34% of all pts had vascular invasion; 82% had extrahepatic spread; and 91% had Barcelona Clinic Liver Cancer stage C; 84% discontinued SOR because of disease progression and 14% because of toxicity. For all treated pts, ORR was 31% (7 had complete response), with median DOR of 17 months; DCR was 49%; the 30-month OS rate was 37%. NIVO + IPI was well tolerated; 38% of pts had grade 3–4 treatment-related adverse events (TRAEs; most common any grade: pruritus and rash; most common grade 3–4: aspartate aminotransferase increase and lipase increase); 5% had grade 3–4 TRAEs leading to discontinuation. Subgroup analyses based on duration of prior SOR therapy and other pt characteristics will be presented. Conclusions: NIVO + IPI led to clinically meaningful benefits, with a manageable safety profile in pts previously treated with SOR. NIVO + IPI may provide a new treatment option for these pts. Clinical trial information: NCT01658878.

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]

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.