Tislelizumab improves overall survival in patients with advanced esophageal squamous cell carcinoma
About Tislelizumab
Tislelizumab (BGB-A317) is a type of precision cancer medicine. This humanized IgG4 anti-PD-1 monoclonal antibody was designed specifically to minimize binding to FcγR on macrophages. In pre-clinical studies, binding to FcγR on macrophages has been shown to compromise the anti-tumor activity of PD-1 antibodies through activation of antibody-dependent macrophage-mediated killing of T effector cells.

Tislelizumab was initially evaluated in a global phase 3 clinical trial in 512 patients with advanced/unresectable or metastatic Squamous Cell Cancer of the Esophagus who did not respond to previous systemic treatments. These patients were treated with standard chemotherapy alone or with weekly tislelizumab and directly compared.
- Tislelizumab was associated was a higher response rate; 20.3% compared to 9.8% for chemotherapy.
- Tslelizumab demonstrated more durable responses lasting an average of 7.1 months, compared to 4.0 months with chemotherapy.
- Median survival duration was 8.6 months tislelizumab compared to 6.3 months with chemotherapy.
- The 12 month survival rate was 37.4% with tislelizumab compared to 23.7% with chemotherapy.
- In patients with high PD-L1 expression, the median survival was 10.3 months with tislelizumab compared to 6.8 months with chemotherapy.
- Compared to chemotherapy, tislelizumab demonstrated a favorable safety profile.

First Line Tislelizumab Improves Survival
Following the encouraging results of tislelizumab compared to chemotherapy researchers then evaluated tislelizumab in combination with chemotherapy.2 The Phase III RATIONALE 306 clinical trial demonstrated that tislelizumab plus chemotherapy significantly improved overall survival when used as a first-line treatment for patients with unresectable, locally advanced or metastatic esophageal squamous cell carcinoma regardless of their PD-L1 score.
The study directly compared tislelizumab plus chemotherapy to chemotherapy alone in 649 patients with unresectable, locally advanced recurrent or metastatic ESCC. Tislelizumab plus chemotherapy modestly delayed cancer progression by about 7 weeks but this translated into a significant survival benefit. Patients treated with tislelizumab plus chemotherapy survived on average 17.2 months compared to 10.6 months in patients receiving chemotherapy.
References:
- Shen L, Kato K, Kim S-B, et al. RATIONALE 302: Randomized, Phase 3 study of tislelizumab vs chemotherapy as second-line treatment for advanced or metastatic esophageal squamous cell carcinoma. ePoster presentation at American Society of Clinical Oncology Annual Meeting (ASCO); June 2021
- Yoon H, Kato K, Raymond E et al. RATIONALE-306: Randomized, global, placebo-controlled, double-blind Phase 3 study of tislelizumab plus chemotherapy versus chemotherapy as first-line treatment for advanced esophageal squamous cell carcinoma. Presented at ESMO-GI on 30 June 2022 (#LBA1).





