Abstract 1583P
Background
Safety of a rechallenge with an immune checkpoint inhibitor (ICI) after an immune-related adverse event (irAE) remains unclear, especially for those patients with ICI class switch.
Methods
All adverse drug reactions involving at least one ICI reported up to December 31, 2021 were extracted from the US Food and Drug Administration Adverse Event Reporting System (FAERS) database. The primary outcome was the recurrence of the initial irAE after an ICI rechallenge with original or different regimen (anti-PD-1 or anti-PD-L1 as one class and anti-CTLA-4 as another class). Secondary outcomes included the factors associated with the recurrence after a rechallenge.
Results
We identified a total of 24092 irAE cases associated with at least one cycle of ICI, which 174 irAEs was associated with ICI rechallenge among 586 patients. For patient with single agent ICI, those rechallenged with different ICI regimen was associated with higher recurrence rate of irAEs than those with original ICI regimen (46.6% vs. 26.5%, p=0.002). Similar tendency has been observed in patients with combination therapy which rechallenged with different ICI regimen was associated with higher recurrence rate of irAEs (75% vs. 28.7%, p=0.006). In a rechallenge, factors such as rechallenge with different ICI regimen, initial treatment cycle, administration of steroids and multiple irAEs were associated with higher irAE recurrence rate. Table: 1583P
IrAEs recurrence after ICI rechallenge in single-agent group
| Initial ICI | Regime of ICI rechallenge | All patients | irAEs recurrence | No irAEs recurrence | P value |
| Anti-CTLA4 | 0.152 | ||||
| Anti-CTLA4 | 19 | 4(21.1%) | 15(78.9%) | ||
| Anti-PD-(L)1 | 24 | 10(41.67%) | 14(58.33%) | ||
| Anti-PD-1 or Anti-PD-L1 | 0.004 | ||||
| Anti-CTLA4 | 31 | 16(51.6%) | 15 (48.4%) | ||
| Anti-PD-(L)1 | 361 | 97(26.9%) | 264(73.1%) |
Conclusions
This study found a 29.7% recurrence rate of the same irAE associated with the discontinuation of ICI therapy after rechallenge. In terms of class switch, those rechallenged with different ICI regimen was associated with higher recurrence rate of irAEs than those with original ICI regimen.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
The National Natural Science Foundation of China, the Natural Science Foundation of Guangdong Province.
Disclosure
All authors have declared no conflicts of interest.