# Are all programmed cell death protein 1 inhibitors the same?

## TL;DR

This paper explores whether different PD-1 inhibitors, used to treat cancer, have meaningful differences in their effects and clinical outcomes.

## Contribution

The paper highlights preclinical and clinical evidence suggesting toripalimab may differ from other PD-1 inhibitors in function and patient outcomes.

## Key findings

- Toripalimab shows distinct PD-1 binding and T cell function profiles compared to pembrolizumab and nivolumab.
- Toripalimab plus chemotherapy showed similar or better outcomes in patients with low/no PD-L1 expression in certain cancers.
- Head-to-head RCTs are needed to confirm clinically meaningful differences between PD-1 inhibitors.

## Abstract

Programmed cell death protein 1 (PD-1) inhibitors have revolutionized the treatment of many cancers, seven of which are approved by the US Food and Drug Administration (FDA). No head-to-head phase 3 randomized controlled trials (RCTs) comparing PD-1 inhibitors have been conducted so it remains unknown whether clinically meaningful differences exist between them. Preclinical studies that have directly compared PD-1 inhibitors support a differentiating profile associated with toripalimab compared to pembrolizumab and nivolumab with regard to their PD-1 binding sites, binding orientations, and impact on T cell function. Findings of similar or greater benefit among patients with low/no PD-L1 expression versus high/intermediate PD-L1 expression with toripalimab plus chemotherapy were also observed in advanced nasopharyngeal carcinoma and non-small cell lung cancer for both overall survival and progression-free survival. However, determination of clinically-meaningful differences between PD-1 inhibitors requires sufficiently powered head-to-head RCTs.