Phase II Single-arm Study of Durvalumab and Tremelimumab with Concurrent Radiotherapy in Patients with Mismatch Repair-proficient Metastatic Colorectal Cancer. Academic Article uri icon

Overview

abstract

  • PURPOSE: Immune checkpoint inhibition (ICI) alone is not active in mismatch repair-proficient (MMR-P) metastatic colorectal cancer (mCRC), nor does radiotherapy alone result in objective systemic benefit. However, combined radiotherapy plus ICI can induce systemic antitumor immunity in preclinical and clinical models. PATIENTS AND METHODS: In this single-center, phase II study, patients with chemotherapy-refractory MMR-P mCRC received durvalumab 1,500 mg plus tremelimumab 75 mg every 4 weeks plus radiotherapy. The primary endpoint was objective response rate (ORR) in nonirradiated lesions. Treatment and efficacy were correlated with peripheral immune cell profiles. RESULTS: We enrolled 24 patients, and report outcomes after a median follow-up of 21.8 (range: 15.9-26.3) months. The ORR was 8.3% (2 patients) [95% confidence interval (CI), 1.0-27.0]. The median progression-free survival was 1.8 (95% CI, 1.7-1.9) months, median overall survival was 11.4 (95% CI, 10.1-17.4) months. Twenty five percent of patients (n = 6) had treatment-related grade 3-4 adverse events. We observed increased circulating CD8+ T lymphocyte activation, differentiation, and proliferation in patients with objective response. CONCLUSIONS: This combination of radiotherapy plus ICI study did not meet the prespecified endpoint criteria to be considered worthwhile for further study. However, rare instances of systemic immune augmentation and regression in nonirradiated lesions were observed (an abscopal response). Combination durvalumab and tremelimumab plus radiotherapy is feasible in MMR-P mCRC with a manageable safety profile. Further studies of novel immunotherapy combinations, and identification of biomarkers predictive of abscopal response are warranted.

authors

publication date

  • January 27, 2021

Research

keywords

  • Antineoplastic Combined Chemotherapy Protocols
  • Chemoradiotherapy
  • Colorectal Neoplasms
  • Immune Checkpoint Inhibitors

Identity

PubMed Central ID

  • PMC8499477

Scopus Document Identifier

  • 85104326667

Digital Object Identifier (DOI)

  • 10.1158/1078-0432.CCR-20-2474

PubMed ID

  • 33504552

Additional Document Info

volume

  • 27

issue

  • 8