Association Between Serum Magnesium Levels and Outcomes of Atezolizumab in Patients With Metastatic Urothelial Carcinoma

Anticancer Res. 2024 May;44(5):2117-2123. doi: 10.21873/anticanres.17017.

Abstract

Background/aim: Evidence suggests that serum magnesium levels are associated with outcomes of immune checkpoint inhibitors (ICIs). However, this association remains under-explored in patients with metastatic urothelial carcinoma (UC) treated with ICIs.

Patients and methods: This prognostic study used individual participant-level data from 1,281 patients with locally advanced or metastatic UC treated with atezolizumab (N=855) or chemotherapy (N=426) who participated in the IMvigor210 and the IMvigor211 trials. Multivariable Cox proportional hazards regression and Fine-Gray subdistribution hazards regression models were used to examine the association of baseline serum magnesium levels with overall survival (OS), progression-free survival (PFS), and immune-related adverse events (irAEs).

Results: No evidence of an association was found between baseline serum magnesium levels and PFS or OS in patients treated with atezolizumab [PFS, hazard ratio (HR)=1.03, 95% confidence interval (CI)=0.78-1.35; OS, HR=1.13, 95%CI=0.84-1.51] or chemotherapy (PFS, HR=0.93, 95%CI=0.62-1.40; OS, HR=0.91, 95%CI=0.59-1.40). We also found no evidence of association with irAEs (subdistribution HR=1.29, 95%CI=0.81-2.07) in patients receiving atezolizumab.

Conclusion: This study found no evidence of an association between baseline serum magnesium levels and treatment outcomes or irAEs in patients with metastatic UC receiving atezolizumab. Contrary to previous research suggesting a role for magnesium in cancer therapy, these results indicate that serum magnesium levels may not serve as a biomarker to predict outcomes in these patients.

Keywords: Atezolizumab; immune checkpoint inhibitor; magnesium; urothelial carcinoma.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Antibodies, Monoclonal, Humanized* / adverse effects
  • Antibodies, Monoclonal, Humanized* / therapeutic use
  • Carcinoma, Transitional Cell / blood
  • Carcinoma, Transitional Cell / drug therapy
  • Carcinoma, Transitional Cell / mortality
  • Carcinoma, Transitional Cell / pathology
  • Carcinoma, Transitional Cell / secondary
  • Female
  • Humans
  • Immune Checkpoint Inhibitors / adverse effects
  • Immune Checkpoint Inhibitors / therapeutic use
  • Magnesium* / blood
  • Male
  • Middle Aged
  • Neoplasm Metastasis
  • Prognosis
  • Treatment Outcome
  • Urinary Bladder Neoplasms / blood
  • Urinary Bladder Neoplasms / drug therapy
  • Urinary Bladder Neoplasms / pathology
  • Urologic Neoplasms / blood
  • Urologic Neoplasms / drug therapy
  • Urologic Neoplasms / mortality
  • Urologic Neoplasms / pathology

Substances

  • atezolizumab
  • Antibodies, Monoclonal, Humanized
  • Magnesium
  • Immune Checkpoint Inhibitors