Introduction

The clinical successes seen with anti-programmed cell death protein 1/programmed death-ligand 1 (anti-PD-[L]1) agents have galvanized the field of immuno-oncology. We evaluated the landscape and trends in immunotherapy trials involving the PD-(L)1 axis in intrathoracic tumors.

Methods

We identified clinical trials involving anti-PD-(L)1 agents on the ClinicalTrials.gov registry through November 13, 2020 for NSCLC, SCLC, mesothelioma, and thymic epithelial tumor. Clinical trials were indexed according to monotherapy versus combination approaches, PD-(L)1 agents under investigation, clinical settings, trial start date, and partner drug(s). We assessed redundancy among the clinical trials.

Results

We found 686 clinical trials investigating anti-PD-(L)1 agents for intrathoracic tumors (540 trials in NSCLC, 96 in SCLC, 38 in mesothelioma, and 12 in thymic epithelial tumor). A total of 23 PD-(L)1 inhibitors are undergoing clinical development. A total of 81% of trials assess combination treatment. The number of clinical trials has been growing exponentially in the past decade. PD-(L)1 blockade was frequently combined with chemotherapy or immunomodulatory therapy. Various strategies are in development to overcome resistance to PD-(L)1 blockade in metastatic NSCLC. PD-(L)1 blockade is also increasingly evaluated in neoadjuvant and adjuvant settings. After the U.S. Food and Drug Administration's approval of an anti-PD-(L)1 agent for a specific indication, 14 trials were launched thereafter, which continued to randomize patients to treatments that were inferior to the best available therapy.

Conclusions

The number of clinical trials investigating anti-PD-(L)1 agents in intrathoracic tumors has experienced a steep increase over the past decade with a notable upward trend for combination trials. To reduce duplicative research efforts and accelerate the development of effective immunotherapeutics, improved coordination among key stakeholders and the adoption of innovative trial designs will be vital.

BACKGROUND: TROP2 (TACSTD2) expression is associated with decreased overall survival (OS) in some solid tumors, and the TROP2-targeting antibody-drug conjugate (ADC) sacituzumab govitecan has been approved in breast and urothelial carcinomas. We aimed to explore the multi-omic landscape associated with TACSTD2 gene expression in various solid tumors to identify patients most likely to benefit from this approach. METHODS: Breast (N = 11 246), colorectal (N = 15 425), hepatocellular (N = 433), pancreatic (N = 5488), and urothelial (N = 4125) tumors were stratified into quartiles by TACSTD2 gene expression, analyzed by next-generation DNA sequencing, whole transcriptome sequencing, and immunohistochemistry at Caris Life Sciences (Phoenix, AZ). Survival data were obtained from insurance claims, and Kaplan-Meier estimates were calculated for molecularly defined cohorts. RESULTS: Several pathogenic mutations were associated with TACSTD2-high tumors, including TP53 in breast, colorectal (CRC), pancreatic, and hepatocellular cancers; KRAS in pancreatic and CRC cancers; ARID1A and FGFR3 in urothelial cancer; and CTNNB1 in hepatocellular cancer. TACSTD2-low breast tumors were enriched for copy number amplifications in CCND1 and FGF/R family member genes. TACSTD2 high was generally associated with more immune cell infiltration and greater T-cell inflammation scores. Patients with TACSTD2-high breast, CRC, and pancreatic cancers demonstrated a significantly shorter OS than TACSTD2-low tumors. This was restricted to CRC with microsatellite stable tumors and patients with pancreatic cancer with KRAS-mutant tumors. Patients with breast cancer with TACSTD2-high tumors also experienced significantly worse OS following immune checkpoint inhibitors. CONCLUSIONS: TACSTD2 expression is associated with key driver alterations and a more active immune microenvironment, suggesting possible combinatorial strategies with TROP2-targeting ADCs plus immunotherapy in various solid tumors.