Outcomes in the Asian subgroup of the phase III randomised HIMALAYA study of tremelimumab plus durvalumab in unresectable hepatocellular carcinoma.

Background & aims: In the global, phase III HIMALAYA study in unresectable hepatocellular carcinoma (uHCC), STRIDE (Single Tremelimumab Regular Interval Durvalumab) improved overall survival (OS) vs. sorafenib; durvalumab was noninferior to sorafenib. HBV is the predominant HCC aetiology in most of Asia vs. HCV or nonviral aetiologies in Western countries and Japan. This analysis evaluated safety and efficacy outcomes for STRIDE and durvalumab monotherapy vs. sorafenib, in HIMALAYA participants enrolled in Asia, excluding Japan.

Methods: In HIMALAYA, participants were randomised to STRIDE, durvalumab, or sorafenib. The Asian subgroup in this analysis included participants enrolled in Hong Kong, India, South Korea, Taiwan, Thailand, and Vietnam. OS, objective response rate (ORR; per Response Evaluation Criteria in Solid Tumors, version 1.1), and safety were assessed in the Asian subgroup and in an exploratory subgroup of participants in Hong Kong and Taiwan.

Results: The Asian subgroup included 479 participants randomised to STRIDE (n=156), durvalumab (n=167), or sorafenib (n=156). OS was improved for STRIDE vs. sorafenib (HR 0.68; 95% CI 0.52-0.89]). The OS HR for durvalumab vs. sorafenib was 0.83 (95% CI 0.64-1.06). In Hong Kong and Taiwan (n=141), OS HRs for STRIDE vs. sorafenib and durvalumab vs. sorafenib were 0.44 (95% CI 0.26-0.77) and 0.64 (95% CI 0.37-1.08), respectively. In the Asian subgroup, ORR (including unconfirmed responses) was numerically higher for STRIDE (28.2%) and durvalumab (18.6%) vs. sorafenib (9.0%), and Grade 3/4 treatment-related adverse events were numerically lower for STRIDE (19.9%) and durvalumab (13.3%) vs. sorafenib (30.5%).

Conclusions: STRIDE improved outcomes vs. sorafenib in the Asian subgroup. These results support the benefits of STRIDE for participants with uHCC globally, including the Asia-Pacific region.

Clinical trial number: NCT03298451 IMPACT AND IMPLICATIONS: The global, phase III HIMALAYA study found that the STRIDE (Single Tremelimumab Regular Interval Durvalumab) regimen improved overall survival (OS), including long-term OS, vs. sorafenib, and that durvalumab monotherapy was noninferior to sorafenib in participants with unresectable hepatocellular carcinoma (uHCC). However, there are differences in the aetiology and clinical practices related to HCC in parts of Asia, compared to Western countries and Japan, which could lead to differences in treatment outcomes between these regions. The results of this analysis demonstrate the benefits of STRIDE for participants in the Asia-Pacific region, consistent with the full, global study population. Overall, these findings continue to support the use of STRIDE in a diverse population, reflective of uHCC globally.