Myocarditis in Patients Starting Combination Checkpoint Inhibitor Therapy: Analysis of a Commercial Claims Database.

Area of Science:

• Oncology
• Immunology
• Cardiology

Background:

• Immune checkpoint inhibitors (ICIs) improve cancer outcomes but can cause immune-related adverse effects.
• Combination ICI therapy may increase the risk of these adverse events, particularly myocarditis.

Purpose of the Study:

• To investigate the incidence of myocarditis in cancer patients receiving dual concurrent versus single ICI therapies.

Main Methods:

• A cohort study analyzed medical and pharmacy claims data from 2011-2022.
• Cox regression quantified risks of myocarditis and heart failure in patients on combination (nivolumab and ipilimumab) versus monotherapy.
• Follow-up was a mean of 226 days in 53,018 patients.

Main Results:

• Myocarditis occurred in 0.7% of combination therapy patients versus 0.2% of monotherapy patients.
• The risk of myocarditis per 1000 patients was 7.40 for combination therapy and 2.37 for monotherapy (RR, 3.12).
• Multivariable analysis showed a hazard ratio of 2.38 for myocarditis with combination therapy; no difference in heart failure risk was observed.

Conclusions:

• Dual ICI therapy is associated with a higher risk of myocarditis compared to monotherapy.
• The majority of myocarditis cases emerged within the initial six months of combination treatment.