Nivolumab (NIVO) plus ipilimumab (IPI) vs chemotherapy (chemo) or NIVO monotherapy for microsatellite instability-high/mismatch repair-deficient (MSI-H/dMMR) metastatic colorectal cancer (mCRC): Expanded analyses from CheckMate 8HW.

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]

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.

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]

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]

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]

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]

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

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]

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]

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]

3550 Background: NIVO + IPI demonstrated robust, durable clinical benefit, and was well tolerated as a 1L therapy in pts with MSI-H/dMMR mCRC in the phase 2 CheckMate 142 study (NCT02060188), leading to the inclusion of NIVO + IPI in the NCCN guidelines as an initial therapy option for these pts. At 52-mo median follow-up, 1L NIVO + IPI continued to demonstrate durable clinical benefit, and no new safety signals were identified. Here we report longer follow-up results. Methods: Pts with MSI-H/dMMR mCRC and no prior treatment for metastatic disease received 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; overall survival (OS); and safety. Results: In total, 45 pts received 1L NIVO + IPI. With median follow-up of 64.2 mo (range, 59.4–68.9 mo), ORR by INV was 71% (95% CI, 56–84%). The proportion of pts with a best overall response of complete response (CR) was 20%, partial response (PR) was 51%, stable disease (SD) was 13%, and progressive disease was 16%. Median DOR (mDOR) was not reached, and the 60-mo DOR rate was 72%. Median PFS (mPFS) by INV and median OS (mOS) were not reached, with 60-mo PFS and OS rates of 55% and 67%, respectively (Table). Among pts alive at the data cutoff (n = 31), 30 remained treatment-free after initial study treatment without receiving any subsequent systemic therapy, with a median treatment-free interval of 34.7 mo (range, 1.6–61.4 mo). Exploratory analysis by tumor mutational burden status will be presented. Safety data are shown in the Table. Conclusions: At 64-mo follow-up, NIVO + IPI continued to demonstrate clinically meaningful survival and durable responses, with mPFS, mOS, and mDOR still not reached, suggesting the potential for long-term clinical benefit. Safety remained consistent with previous data. These findings further support current recommendations for NIVO + IPI as a 1L treatment for pts with MSI-H/dMMR mCRC. Clinical trial information: NCT02060188 . [Table: see text]

97 Background: NIVO + IPI demonstrated robust, durable clinical benefit and was well tolerated as a 1L therapy in pts with MSI-H/dMMR mCRC in the phase 2 CheckMate 142 study (NCT02060188), leading to the inclusion of NIVO + IPI in the NCCN guidelines as an initial therapy option for these pts. At 52-mo median follow-up, 1L NIVO + IPI continued to demonstrate durable clinical benefit, and no new safety signals were identified. Here we report longer follow-up results. Methods: Pts with MSI-H/dMMR mCRC and no prior treatment for metastatic disease received 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; overall survival (OS); and safety. Results: In total, 45 pts received 1L NIVO + IPI. With median follow-up of 64.2 mo (range, 59.4–68.9 mo), ORR by INV was 71% (95% CI, 56–84%). The proportion of pts with a best overall response of complete response (CR) was 20%, partial response (PR) was 51%, stable disease (SD) was 13%, and progressive disease was 16%. Median DOR (mDOR) was not reached, and the 60-mo DOR rate was 72%. Median PFS (mPFS) by INV and median OS (mOS) were not reached, with 60-mo PFS and OS rates of 55% and 67%, respectively (Table). Among pts alive at the data cutoff (n = 31), 30 remained treatment-free after initial study treatment without receiving any subsequent systemic therapy, with a median treatment-free interval of 34.7 mo (range, 1.6–61.4 mo). Exploratory analysis by tumor mutational burden status will be presented. Safety data are shown in the Table. Conclusions: At 64-mo follow-up, NIVO + IPI continued to demonstrate clinically meaningful survival and durable responses, with mPFS, mOS, and mDOR still not reached, suggesting the potential for long-term clinical benefit. Safety remained consistent with previous data. These findings further support current recommendations for NIVO + IPI as a 1L treatment for pts with MSI-H/dMMR mCRC. Clinical trial information: NCT02060188 . [Table: see text]

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]

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]

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]