Introduction: Immune checkpoint inhibitors (ICIs) have transformed outcomes in several cancers including melanoma. Patients on ICIs are at risk of immune related adverse events (ir-AEs). Checkpoint inhibitor Pneumonitis (CIP) is an uncommon but potentially life-threatening ir-AE. Little evidence exists to guide management. We present our experience managing CIP in a tertiary interstitial lung disease (ILD) service.?
Methods: We retrospectively reviewed electronic case notes and imaging of consecutive patients diagnosed with CIP between July 2020 to December 2022.
Results:
| Total number of patients | n=26 |
| Male | n=19 |
| Female | n=7 |
| Median age | 72 years old |
| Median time of onset post ICI initiation | 6.5 months (1 week?21 months) |
| Median duration of treatment | 9 months (2 weeks?25 months) |
| Mean (SD) FVC% predicted | 87% (22) |
| Mean (SD) TLCO% predicted | 67% (18) |
| Cancer type | Melanoma (13), Non-small cell lung (6), Squamous cell cancer (SCC) skin (2), SCC tonsil (1), Renal cell (2), Mesothelioma (1), Bladder (1) |
| Presence of distant metastasis | n=18 (69%) |
The most common CT appearances were diffuse ground glass opacification followed by organising pneumonia. 7 patients (27%) had new radiological changes consistent with CIP but were asymptomatic. Pre-existing ILD was present in 8 patients (31%) and 14 patients (53%) had a history of previous irAEs. Combination ICIs were used in 7 patients (27%). Mycophenolate mofetil was used as a steroid sparer in 23% of patients. There were 4 ICI toxicity related deaths (15%).
Conclusion: CIP can manifest later than previously described and commonly occurs alongside other irAEs. Treatment often involves a prolonged steroid course. More studies are needed to evaluate the role of steroid sparing agents.