AstraZeneca PLC announced positive high-level results from the HIMALAYA Phase III trial showed a single, high priming dose of tremelimumab added to Imfinzi (durvalumab) demonstrated a statistically significant and clinically meaningful overall survival (OS) 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. This novel dose and schedule of tremelimumab, an anti-CTLA4 antibody, and Imfinzi is called the STRIDE regimen (Single Tremelimumab Regular Interval Durvalumab). The combination demonstrated a favourable safety profile, and the addition of tremelimumab to Imfinzi did not increase severe hepatic toxicity. Imfinzi alone demonstrated non-inferior OS to sorafenib with a numerical trend in favour of Imfinzi and an improved tolerability profile compared 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. Only 7% of patients with advanced disease survive five years. The data from the HIMALAYA Phase III trial will be presented at a forthcoming medical meeting. 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. HIMALAYA was a randomised, open-label, multicentre, global Phase III trial of Imfinzi monotherapy and the STRIDE regimen, comprising a single priming dose of tremelimumab 300mg added to Imfinzi 1,500mg followed by Imfinzi every four weeks versus sorafenib, a standard-of-care multi-kinase inhibitor, in a total of 1,324 patients with unresectable, advanced HCC who had not been treated with prior systemic therapy and were not eligible for locoregional therapy (treatment localised to the liver and surrounding tissue). The trial was conducted in 190 centres across 16 countries, including in the US, Canada, Europe, South America and Asia. The primary endpoint was OS for STRIDE versus sorafenib and key secondary endpoints included OS for Imfinzi versus sorafenib, objective response rate and progression-free survival (PFS) for STRIDE and for Imfinzi alone. Imfinzi (durvalumab) is a human monoclonal antibody that binds to the PD-L1 protein and blocks the interaction of PD-L1 with the PD-1 and CD80 proteins, countering the tumour's immune-evading tactics and releasing the inhibition of immune responses. Imfinzi is the only approved immunotherapy in the curative-intent setting of unresectable, Stage III non-small cell lung cancer (NSCLC) in patients whose disease has not progressed after chemoradiation therapy and is the global standard of care in this setting based on the PACIFIC Phase III trial. Imfinzi is also approved in the US, EU, Japan, China and many other countries around the world for the treatment of extensive-stage small cell lung cancer (ES-SCLC) based on the CASPIAN Phase III trial. Imfinzi is also approved for previously treated patients with advanced bladder cancer in several countries. Since the first approval in May 2017, more than 100,000 patients have been treated with Imfinzi. In 1st-line Stage IV NSCLC, positive results from the POSEIDON Phase III trial showed Imfinzi plus chemotherapy with a short course of tremelimumab 75mg demonstrated a statistically significant and clinically meaningful improvement in OS and PFS compared to chemotherapy. As part of a broad development programme, Imfinzi is being tested as a single treatment and in combinations with other anti-cancer treatments for patients with NSCLC, SCLC, bladder cancer, HCC, biliary tract cancer (BTC), oesophageal cancer, gastric and gastroesophageal cancer, cervical cancer, ovarian cancer, endometrial cancer, and other solid tumours. Tremelimumab is a human monoclonal antibody and potential new medicine that targets the activity of cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). Tremelimumab blocks the activity of CTLA-4, contributing to T-cell activation, priming the immune response to cancer and fostering cancer cell death. Tremelimumab is being tested in a clinical trial programme in combination with Imfinzi in NSCLC, SCLC, bladder cancer and liver cancer.