1008P IMbrave150: Management of adverse events of special interest (AESIs) for atezolizumab (atezo) and bevacizumab (bev) in unresectable HCC

In the phase III IMbrave150 trial, atezo + bev demonstrated a statistically significant and clinically meaningful improvement in overall survival (OS) and progression-free survival (PFS) vs sorafenib (sor) in patients (pts) with unresectable HCC. Here we report on the AESIs for both atezo and bev in IMbrave150. Eligible pts (N = 501) had unresectable HCC and were randomised 2:1 to receive atezo 1200 mg IV q3w + bev 15 mg/kg IV q3w or sor 400 mg PO bid until unacceptable toxicity or loss of clinical benefit per investigator. Co-primary endpoints were OS and PFS by independent review facility–assessed RECIST 1.1. AESIs were defined by the sponsor and reported without judgement of causality. AESIs for atezo were based on the immune-mediated risks of atezo and other checkpoint inhibitors; AESIs for bev were based on known adverse drug reactions (ADRs) with bev. Analyses explored the incidence, nature and severity of AESIs as well as corticosteroid use. The safety-evaluable population included 329 pts in the atezo + bev arm and 156 pts in the sor arm. Median follow-up was 8.6 mo (data cutoff: 29 Aug 2019); median tx durations were 7.4 (atezo), 6.9 (bev) and 2.8 (sor) mo. AESIs for atezo occurred in 69% of pts receiving atezo + bev and also in 82% of pts receiving sor (table). 12% of pts in the atezo + bev arm vs 3% of pts in the sor arm experienced AESIs requiring systemic corticosteroid tx within 30 days of AE onset. AESIs for bev occurred in 58% of pts receiving atezo + bev and 49% of pts receiving sor. The reported events were ADRs well known with bev, and their frequency and severity were consistent with the safety profile of bev and the underlying disease. In IMbrave150, AESIs for atezo and bev were manageable. Further, the nature and severity of AESIs were consistent with the known safety profiles of the individual agents and the underlying disease.Table: 1008PAESIs, n (%)aAtezo + Bev n = 329Sor n = 156AllG3-4AllG3-4For atezoPts with ≥ 1226 (69)85 (26)128 (82)47 (30)Hepatic eventsb142 (43)70 (21)62 (40)26 (17)Inc AST64 (20)23 (7)26 (17)8 (5)Inc blood bilirubin43 (13)8 (2)22 (14)10 (6)Inc ALT46 (14)12 (4)14 (9)2 (1)Ascites23 (7)6 (2)9 (6)2 (1)Rash64 (20)2 (1)96 (62)21 (14)Hypothyroidism36 (11)04 (3)0Infusion-related reactions36 (11)8 (2)00For bevPts with ≥ 1190 (58)76 (23)76 (49)29 (19)Hypertension102 (31)50 (15)40 (26)19 (12)Bleeding/haemorrhage83 (25)21 (6)27 (17)9 (6)Epistaxis34 (10)07 (5)1 (1)Upper GI bleedingc24 (7)15 (5)8 (5)8 (5)Proteinuria70 (21)10 (3)13 (8)1 (1)Inc, increased.a In ≥ 5% of pts.b ≥ 1 category possible.c Grouped MedDRA PT. Open table in a new tab