TOPLINE

Among patients with mild immune-related pneumonitis, a 3-week corticosteroid regimen did not meet noninferiority to the standard 6-week regimen, showing lower rates of treatment success and higher rates of relapse or exacerbation.

METHODOLOGY

• This randomized noninferiority trial assessed whether a shorter corticosteroid regimen was noninferior to the guideline‑recommended 6‑week regimen in patients with mild immune‑related pneumonitis.
• Researchers included 105 patients (median age, 72 years; 81% men) across 22 Japanese centers and assigned them to receive either a 3-week (n = 51) or a 6-week (n = 54) corticosteroid regimen.
• Both groups received prednisolone at 1 mg/kg/d for 1 week, then tapered per protocol to complete either the 3‑week regimen (median duration of exposure, 25 days) or the 6‑week regimen (median duration of exposure, 41 days).
• The primary endpoint was treatment success at 8 weeks, defined as having resting room-air oxygen saturation of at least 90% with no increase in steroid dose or prolongation of steroid administration for worsening pneumonitis.
• Noninferiority required the lower bound of the two-sided 80% CI for the treatment difference to be greater than -16 percentage points.

TAKEAWAY

• At 8 weeks, the rate of treatment success was 66.7% with the 3-week regimen and 85.2% with the 6-week regimen; the difference was -18.5 percentage points (80% CI, -29.0% to -7.9%), which did not meet the noninferiority criterion. A predefined exploratory analysis showed that the 6-week regimen was superior (P = .013).
• Treatment failure at 8 weeks occurred significantly more often with the 3-week regimen than with the 6-week regimen (difference, 24.1 percentage points), and relapse or exacerbation over the study period followed the same pattern (41.1% vs 24.1%; P < .05 for both).
• Adverse events of grade 3 or higher occurred in 12% of patients in the 3-week group and 24% in the 6-week group. Common events were hyperglycemia and elevated transaminase and creatinine levels; none led to stopping steroids.
• Overall survival was comparable between groups. Quality-of-life scores improved from baseline in both arms, with a numerically larger — but not statistically significant — gain in the 6-week group.

IN PRACTICE

“Through this trial, the 6-week corticosteroid regimen endorsed by the guidelines was firmly established as an evidence-based standard for treating mild irP [immune-related pneumonitis],” the authors of the study wrote.

SOURCE

The study was led by Daichi Fujimoto, Hyogo Medical University, Nishinomiya, Japan. It was published online on July 3, 2026, in the American Journal of Respiratory and Critical Care Medicine.

LIMITATIONS

Because the trial was open-label, it may have introduced treatment and ascertainment biases. The small number of deaths limited statistical power and prevented definitive conclusions about overall survival. With only one patient with melanoma and a heterogeneous mix of tumor types, the findings had limited generalizability to melanoma, and assessment of tumor‑specific differences was not feasible.

DISCLOSURES

The trial was supported by the Japan Lung Cancer Society. Several authors disclosed receiving grants, personal fees, research funding, or consulting fees and having other ties with multiple organizations.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.