Results from a new phase III study found that combining PD-L1 and TIGIT inhibitors plus chemotherapy in the first-line setting prolongs survival in an Asian population of patients with metastatic or locally advanced oesophagal squamous cell carcinoma.

This treatment combination has the potential to boost the body's ability to fight cancer and may ultimately lead to better outcomes for these patients with oesophagal squamous cell carcinoma that cannot be surgically removed or has spread to other parts of the body.

The research was presented at the 2024 American Society of Clinical Oncology (ASCO) Gastrointestinal Cancers Symposium, taking place January 18-20 in San Francisco, California. 

“Oesophageal squamous cell carcinoma has a significant impact on patients’ functioning and quality of life, including symptoms such as trouble sleeping, weight loss, anxiety and depression, pain, and difficulty swallowing. Given the demographics of patients with oesophageal cancer, the study was intended to focus on the Asian population,” said lead study author Chih-Hung Hsu, MD, PhD, from the National Taiwan University Hospital in Taipei, Taiwan 

The SKYSCRAPER-08 study evaluated the efficacy and safety of the addition of the T-cell immunoglobulin and ITM domain (TIGIT) inhibitor tiragolumab to the programmed cell death protein 1 (PD-L1) inhibitor atezolizumab in combination with chemotherapy compared with placebo plus chemotherapy as first-line treatment in patients with unresectable locally advanced, unresectable recurrent, or metastatic oesophageal squamous cell carcinoma. Overall, 461 patients were enrolled at 67 centres in mainland China, South Korea, Thailand, Taiwan, and Hong Kong. The primary endpoints were independent review facility-assessed progression-free survival (PFS) and overall survival (OS).

In this randomised, double-blind, placebo-controlled study, 229 were randomised to receive the immunotherapy combination plus chemotherapy and 232 patients were randomised to receive the placebo plus chemotherapy.

After a minimum survival follow-up of 6.5 months, the median independent review facility-assessed PFS was 6.2 months in patients who received the tiragolumab plus atezolizumab plus chemotherapy vs. 5.4 months in patients who received the placebo plus chemotherapy.

After a minimum survival follow-up of 14.5 months, the median OS was 15.7 months in patients who received the tiragolumab plus atezolizumab plus chemotherapy vs. 11.1 months in patients who received the placebo plus chemotherapy.

Overall, treatment-related side effects occurred in 98.2% of patients in both treatment arms. Most of the side-effects seen in both arms are those related to chemotherapy. 

Side effect of note in the tiragolumab plus atezolizumab and chemotherapy arm were immune-mediated rash (38.6%), immune-mediated hepatitis (35.1%), immune-mediated hypothyroidism (17.5%), infusion-related reaction (17.5%), and immune-related pneumonitis (7.5%). Most of the side effects of special interest were grade 1 or grade 2 and were easily manageable.

 “Oesophageal squamous cell carcinoma accounts for most oesophageal cancer cases worldwide. This phase III trial demonstrates that dual immunotherapy plus chemotherapy with the novel checkpoint inhibitor, tiragolumab, improves progression-free and overall survival without compromising safety,” said Pamela Kunz, MD, ASCO Expert

Studies to investigate tiragolumab plus atezolizumab as a maintenance therapy following definitive chemoradiotherapy and the combination of tiragolumab plus atezolizumab with neoadjuvant chemoradiotherapy followed by surgery for locally advanced oesophageal cancer are ongoing.

Source: ASCO