Makowsky, Mallory

Background and Aims: In the global phase III HIMALAYA study in unresectable HCC, STRIDE significantly improved overall survival (OS) versus sorafenib; durvalumab was noninferior to sorafenib. Immune checkpoint inhibitor studies have shown an association between the occurrence of immune-mediated adverse events (imAEs) and improved OS. We assessed potential associations between the occurrence of imAEs and OS, and temporal patterns of imAEs, in HIMALAYA. Approach and Results: OS in participants who did and did not experience imAEs and the frequency and timing of imAEs were assessed for STRIDE and durvalumab in the safety analysis set of HIMALAYA. imAEs occurred in 139/388 (35.8%) and 64/388 (16.5%) participants with STRIDE and durvalumab, respectively; most were low grade. OS HRs (95% CI) in participants who experienced imAEs versus those who did not were 0.73 (0.56–0.95) for STRIDE and 1.14 (0.82–1.57) for durvalumab. The 36-month OS rate (95% CI) for STRIDE was 36.2% (28.1–46.7) and 27.7% (22.4–34.2) in participants who did and did not experience imAEs, respectively. The most common imAE category with STRIDE was endocrine events (16.5%). Most imAEs occurred ≤3 months after treatment initiation. Conclusions: Participants who experienced imAEs with STRIDE had a numerical improvement in OS versus those who did not, which was not observed for durvalumab. Long-term OS with STRIDE was observed regardless of imAEs. Most imAEs were low grade, manageable, and occurred in the first 3 months after treatment initiation. Results continue to support the benefits of STRIDE in a diverse population that reflects unresectable HCC globally.

4004 Background: Immune checkpoint inhibitor (ICI) studies have shown an association between the occurrence of imAEs and outcomes. In the Phase 3 HIMALAYA study (NCT03298451) in uHCC, STRIDE (Single T Regular Interval D) significantly improved overall survival (OS) vs sorafenib (S), and D monotherapy was noninferior to S. STRIDE and D had manageable safety (Abou-Alfa et al. NEJM Evid 2022). STRIDE is approved for uHCC in the United States and Japan and recommended for approval by the European Medicines Agency; D is approved in Japan. This exploratory analysis assessed the association between imAEs and outcomes in HIMALAYA. Methods: Safety was assessed in participants (pts) who received ≥1 dose of STRIDE (T 300 mg [one dose] plus D 1500 mg once every 4 weeks [Q4W]) or D (1500 mg Q4W). imAEs were AEs of special interest associated with drug exposure and consistent with an immune-mediated mechanism of action with no found alternate etiology. Median OS (mOS) and OS rates were estimated using the Kaplan–Meier method. OS hazard ratios (HRs) and 95% CIs were calculated using Cox modeling, with imAEs as a time-varying covariate and stratified by etiology (HBV/HCV/others), ECOG (0/1), and macro-vascular invasion (yes/no) for pts with vs without imAEs of any grade. Pts with >1 imAE were counted once. Results: In total, 388 pts (STRIDE) and 388 pts (D) were included in the analysis. Any grade imAEs, Grade 3 or 4 imAEs, and imAEs leading to discontinuation occurred in 139 (35.8%), 49 (12.6%), and 22 (5.7%) pts, respectively for STRIDE and 64 (16.5%), 25 (6.4%), and 10 (2.6%) pts, respectively for D. imAEs requiring high-dose steroids (≥40 mg prednisone or equivalent daily) occurred in 78 (20.1%) pts for STRIDE and 37 (9.5%) pts for D. An improvement in OS was seen with STRIDE in pts with imAEs vs pts without (HR, 0.73; 95% CI, 0.56–0.95). OS rates at 6, 12, and 24 months (mo) were higher for STRIDE in pts with imAEs vs pts without. The association between imAEs and OS was less clear for D and may be limited by small pt number. In a landmark analysis of pts with vs without imAEs within 6 mo of STRIDE (n=307) or D (n=287), OS HRs (95% CIs) were 0.65 (0.47–0.90) and 1.39 (0.95–2.04), respectively. Conclusions: In HIMALAYA, imAEs with STRIDE or D were manageable and generally low grade. In this exploratory analysis, the occurrence of imAEs was associated with improved OS for STRIDE, generally consistent with findings for other ICIs. Clinical trial information: NCT03298451 . [Table: see text]

PURPOSE This phase I/II study evaluated tremelimumab (anticytotoxic T-lymphocyte–associated antigen-4 monoclonal antibody) and durvalumab (antiprogrammed death ligand-1 monoclonal antibody) as monotherapies and in combination for patients with unresectable hepatocellular carcinoma (HCC), including a novel regimen featuring a single, priming dose of tremelimumab (ClinicalTrials.gov identifier: NCT02519348 ). PATIENTS AND METHODS Patients with HCC who had progressed on, were intolerant to, or refused sorafenib were randomly assigned to receive T300 + D (tremelimumab 300 mg plus durvalumab 1,500 mg [one dose each during the first cycle] followed by durvalumab 1,500 mg once every 4 weeks), durvalumab monotherapy (1,500 mg once every 4 weeks), tremelimumab monotherapy (750 mg once every 4 weeks [seven doses] and then once every 12 weeks), or T75 + D (tremelimumab 75 mg once every 4 weeks plus durvalumab 1,500 mg once every 4 weeks [four doses] followed by durvalumab 1,500 mg once every 4 weeks). Safety was the primary end point. Secondary end points included objective response rate (ORR) by Response Evaluation Criteria in Solid Tumors v1.1 and overall survival; exploratory end points included circulating lymphocyte profiles. RESULTS A total of 332 patients were enrolled (T300 + D, n = 75; durvalumab, n = 104; tremelimumab, n = 69; and T75 + D, n = 84). Tolerability was acceptable across arms, with grade ≥ 3 treatment-related adverse events occurring in 37.8%, 20.8%, 43.5%, and 24.4%, respectively. Confirmed ORRs (95% CI) were 24.0% (14.9 to 35.3), 10.6% (5.4 to 18.1), 7.2% (2.4 to 16.1), and 9.5% (4.2 to 17.9), respectively. An early expansion of CD8+ lymphocytes was associated with response across arms, with highest proliferating CD8+ lymphocyte levels occurring in the T300 + D arm. The median (95% CI) overall survival was 18.7 (10.8 to 27.3), 13.6 (8.7 to 17.6), 15.1 (11.3 to 20.5), and 11.3 (8.4 to 15.0) months in the T300 + D, durvalumab, tremelimumab, and T75 + D arms, respectively. CONCLUSION All regimens were found to be tolerable and clinically active; however, the T300 + D regimen demonstrated the most encouraging benefit-risk profile. The unique pharmacodynamic activity and association with ORR of the T300 + D regimen further support its continued evaluation in HCC.

4073 Background: Durvalumab and tremelimumab, investigational monoclonal antibodies against PD-L1 and CTLA-4 immune checkpoints, respectively, have shown efficacy in monotherapy and offer promise in combination for patients (pts) with HCC. This is a phase I/II, open-label, randomized study of durvalumab combined with tremelimumab in unresectable HCC. Methods: Phase I part of this study is a safety run-in cohort treated at the recommended phase II doses of the durvalumab/tremelimumab combination (20 and 1 mg/kg IV Q4W respectively for 4 doses followed by 20 mg/kg Q4W durvalumab alone) in pts with unresectable HCC with or without concomitant HBV or HCV infection who progress on, are intolerant to, or have refused sorafenib therapy. Secondary objectives include evaluation of antitumor activity. Here we present results of a preplanned analysis from the completed phase I part of the study. Results: As of 10 January 2017, 40 pts have been enrolled (11 HBV+, 9 HCV+, 20 uninfected). 30% had no prior systemic therapy; 93% were Child Pugh Class A. 24 (60%) had ≥1 treatment-related AE; 20% had ≥1 grade ≥3 related AE. Most common (≥15%) treatment-related AEs: fatigue (20%), increased ALT (18%), pruritus (18%), and increased AST (15%). Most common grade ≥3 related AE was asymptomatic increased AST (10%). 24 pts have discontinued treatment: 3 due to treatment-related AEs (grade 3 pneumonitis, grade 3 colitis/diarrhea, asymptomatic grade 4 elevated AST and ALT), 16 due to progressive disease, 4 due to death unrelated to treatment (cardiac arrest, variceal bleed, progressive disease, probable HCC rupture), and 1 other (pt entered hospice care). 40 pts were evaluable for response at ≥16 weeks follow-up. Conclusions: No unexpected safety signals with durvalumab and tremelimumab were seen in this unresectable HCC population. Clinical activity observed predominantly in uninfected pts though interpretation limited by small subsets. Enrollment to the phase II portion of the study is ongoing. Clinical trial information: NCT02519348. [Table: see text]