AstraZeneca PLC (LSE:AZN) said a final phase trial using a combination of tremelimumab and Imfinzi (durvalumab) showed an improved survival rate for patients with liver cancer.
The HIMALAYA Phase III trial, where a single, high priming dose of tremelimumab, an anti-CTLA4 antibody, was added to Imfinzi, demonstrated a statistically significant and clinically meaningful overall survival benefit versus sorafenib as a 1st-line treatment for patients with unresectable hepatocellular carcinoma (HCC), who had not received prior systemic therapy and were not eligible for localised treatment.
In a statement, AstraZeneca said the combination of the two drugs demonstrated a favourable safety profile, and the addition of tremelimumab to Imfinzi did not increase severe hepatic toxicity.
The trial met its primary endpoint of overall survival with a single priming dose of tremelimumab plus Imfinzi every four weeks versus sorafenib, while Imfinzi alone demonstrated non-inferior overall survival to sorafenib.
Liver cancer, of which HCC is the most common type, is the third leading cause of cancer death and the sixth most commonly diagnosed cancer worldwide with approximately 900,000 people diagnosed each year, AstraZeneca said. Only 7% of patients with advanced disease survive five years.
Ghassan Abou-Alfa, MD, MBA, attending physician at Memorial Sloan Kettering Cancer Center and principal investigator in the HIMALAYA Phase III trial, said: "HIMALAYA is the first Phase III trial to add a novel single priming dose of an anti-CTLA4 antibody to another checkpoint inhibitor, durvalumab. This serves to boost the patient's own immune system against their liver cancer, aiming to maximise long-term survival with minimal side effects. This is very exciting news for our patients."
Susan Galbraith, executive vice president, Oncology R&D, AstraZeneca, said: "This is the first time a dual immunotherapy regimen has improved overall survival as a 1st-line treatment for patients with unresectable liver cancer for whom treatment options are limited and long-term outcomes are poor."
Imfinzi and tremelimumab were granted Orphan Drug Designations in the US for the treatment of HCC in 2020. Tremelimumab was also granted orphan designation in the EU in HCC in 2020.