The treatment of unresectable liver cancer has long been a challenge in the medical field. However, a recent randomized trial called EMERALD-1 has shown promising results in improving outcomes using transarterial chemoembolization (TACE) in combination with immunotherapy. This article will analyze the trial and its implications for the treatment of hepatocellular carcinoma (HCC).
The EMERALD-1 trial revealed that patients who received durvalumab and bevacizumab in addition to TACE had a significantly longer median progression-free survival (PFS) compared to those who received TACE plus placebo. The improvement in outcomes was primarily driven by bevacizumab. Patients who received only durvalumab had a similar median PFS to the placebo arm, indicating that bevacizumab played a crucial role in enhancing the efficacy of the treatment. The occurrence of adverse events (AEs) was similar across all three treatment groups.
It is important to note that the addition of durvalumab and bevacizumab to TACE did result in a higher incidence of Grade 3/4 AEs possibly related to the study treatment. Approximately 25.5% of patients in the durvalumab-bevacizumab arm experienced these AEs, compared to about 6% in the TACE plus placebo or single-agent durvalumab arms. However, the rates of fatal AEs did not differ significantly among the treatment groups, indicating that the safety profile of the combination therapy was manageable.
According to Riccardo Lencioni, MD, the lead researcher of the EMERALD-1 trial, the study is the first global phase III trial to demonstrate a statistically significant and clinically meaningful improvement in PFS with an immunotherapy and TACE-based regimen in unresectable HCC eligible for embolization. The trial’s findings were consistent across all clinical subgroups, further validating the efficacy of the combination therapy. However, it is important to acknowledge that the trial did not address the issue of whether PFS is an adequate surrogate for overall survival (OS).
Josep M. Llovet, MD, PhD, an invited discussant of the EMERALD-1 trial, highlighted the ongoing debate on whether PFS is a suitable surrogate for OS in advanced HCC. A recent analysis of 27 phase III trials in advanced HCC has suggested that a hazard ratio (HR) below 0.6 is needed for PFS to be a valid surrogate. In the EMERALD-1 trial, the absolute PFS difference translated into an HR of 0.77, indicating a positive outcome in overall survival. Llovet emphasized that all trials with an HR below 0.6 have demonstrated positive results in overall survival. Conversely, trials with an HR above the threshold have uncertain outcomes.
Llovet also discussed the role of bevacizumab in advanced HCC based on the results of another recent study. The study demonstrated that atezolizumab plus bevacizumab was more effective than single-agent sorafenib. However, monotherapy with an immune checkpoint inhibitor did not yield significant results. Llovet’s own study further revealed that a third of the tumors were immunocompetent and responded well to immunotherapy, while the remaining two-thirds were immunologically “cold” tumors. The presence of notch signaling, a marker of resistance to bevacizumab, in cold tumors diminished their response to the treatment. On the other hand, downregulation of NRP1, a marker of response to bevacizumab, enhanced the effectiveness of the therapy.
Despite the limitations of PFS as a surrogate for survival, the EMERALD-1 trial marks a significant step forward in the treatment of unresectable liver cancer. The combination of durvalumab, bevacizumab, and TACE has shown superior outcomes compared to TACE alone. The trial’s findings highlight the importance of bevacizumab in combination with immunotherapy and suggest that the combination regimen can become the standard of care in intermediate HCC. However, further research is needed to fully understand the efficacy and safety of this treatment approach. The EMERALD-1 trial sets the stage for future advancements in the field, offering hope to patients with unresectable liver cancer.
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