Add-on tiragolumab improves antitumour response in unresectable HCC

In the treatment of patients with unresectable hepatocellular carcinoma (HCC), the addition of tiragolumab to atezolizumab plus bevacizumab yields meaningful improvements in antitumour response and disease control, according to data from an open-label phase 1b–2 study.

The study included 59 adult patients (median age 65 years, 79 percent male, 40 percent Asian) with previously untreated locally advanced unresectable HCC, an ECOG performance status of 0–1, Child-Pugh class A disease, and a life expectancy of at least 3 months.

The patients were randomly assigned to receive treatment with atezolizumab 1,200 mg plus bevacizumab 15 mg/kg alone (n=18) or in combination with tiragolumab 600 mg (n=41). Treatment was administered via intravenous infusion every 3 weeks on day 1 of each 21-day cycle, lasting until unacceptable toxic effects or loss of clinical benefit, whichever occurred first.

Objective response rate (ORR) was the primary endpoint. Safety was also assessed. One patient in the tiragolumab group withdrew from the study before receiving any treatment.

The median follow-up was 20.6 months in the add-on tiragolumab group and 14.0 months in the atezolizumab plus bevacizumab group. ORR was 43 percent vs 11 percent, respectively.

Adverse events were recorded in all patients in both groups. Of note, more patients in the add-on tiragolumab group vs the atezolizumab plus bevacizumab group had pruritis (50 percent vs 17 percent), arthralgia (33 percent vs 11 percent), and diarrhoea (30 percent vs 6 percent), most of which were grade 1–2.

The most frequent grade 3–4 adverse events were hypertension (15 percent in the add-on tiragolumab group vs 11 percent in the atezolizumab plus bevacizumab group), aspartate aminotransferase elevation (8 percent vs 6 percent, respectively), and proteinuria (5 percent vs 11 percent). Serious adverse events occurred in 53 percent vs 56 percent, respectively. Treatment-related deaths were documented in one patient in the add-on tiragolumab group and in two patients in the atezolizumab plus bevacizumab group.

The addition of tiragolumab to atezolizumab plus bevacizumab showed no negative impact on the incidence of treatment-related or immune-mediated adverse events, and no new safety signals emerged.