AstraZeneca has received the US Food and Drug Administration (FDA) approval for the use of Imjudo (tremelimumab) in combination with anti-PD-L1 antibody Imfinzi (durvalumab) in the treatment of patients having unresectable hepatocellular carcinoma (HCC).

The new combination treatment, known as the STRIDE regimen, consists of a single dosage of the anti-CTLA-4 antibody Imjudo 300mg added to the Imfinzi 1500mg followed by Imfinzi every four weeks. STRIDE expands to Single Tremelimumab Regular Interval Durvalumab.

Imjudo, which is a human monoclonal antibody, targets the activity of cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). It inhibits the activity of CTLA-4 to contribute to the activation of T-cells to prime the immune response to cancer and promoting cancer cell death.

The FDA approval for the Imjudo, Imfinzi combination in the type of liver cancer was based on the positive findings from the HIMALAYA phase 3 trial.

The results from the late stage trial showed that the patients who received Imjudo and Imfinzi together had a 22% lower risk of dying compared to those who received sorafenib.

The findings also showed that an estimated 31% of patients who received the combination therapy were still living three years later, compared to 20% of sorafenib-treated patients at the same time.

AstraZeneca oncology business unit executive vice president Dave Fredrickson said: “With this first regulatory approval for Imjudo, patients with unresectable liver cancer in the US now have an approved dual immunotherapy treatment regimen that harnesses the potential of CTLA-4 inhibition in a unique combination with a PD-L1 inhibitor to enhance the immune response against their cancer.”

The HIMALAYA phase 3 trial was a randomised, open-label, multicentre study of Imfinzi monotherapy and a regimen made up of a single priming dose of Imjudo 300mg added to Imfinzi 1500mg, followed by Imfinzi once in four weeks in comparison to sorafenib, which is a standard-of-care multi-kinase inhibitor.

Conducted across 181 centres in 16 countries, AstraZeneca said that the trial enrolled a total of 1,324 patients with unresectable, advanced HCC.

Overall survival (OS) for the investigational combination compared to sorafenib was the primary endpoint. The important secondary endpoints were OS for Imfinzi compared to sorafenib, objective response rate, and progression-free survival for both the combination and for Imfinzi alone, the pharmaceutical firm said.