Background: Combined anti-PD1 and anti-CTLA4 immunotherapy is a common first line of treatment in advanced solid tumours such as melanoma, non-small cell lung cancer (NSCLCa), mesothelioma and renal cell carcinoma (RCC). Immune-related adverse events (irAE) are well documented and described in clinical trial settings, however less is known about patterns of toxicities in between tumour types in real world settings.
Aim: To describe the pattern of anti-PD1 and anti-CTLA4 toxicities between tumour types at a single centre.
Methods: This is a retrospective observational study of patients (pts) at Nepean Cancer and Wellness Centre who received combined immunotherapy for metastatic cancer from March 2018 to September 2023. Pts were evaluated for toxicities at each clinical visit with history, physical examination and symptoms or signs of adverse events and laboratory results were collected.
Results: Eighty two pts were identified (32 melanoma, 23 mesothelioma, 7 NSCLCa, 18 RCC, 2 other). Median age was 65 years (range 28 - 89), 72% of pts were male, 88% had ECOG PS 0-1. 70% of pts had ≥3 sites of metastatic disease, 27% of pts had brain metastases. For any grade irAEs, 25/82 (30%) in skin rash, 10/82 (12%) pneumonitis, 11/82 (13%) thyroid dysfunction, 4/82 (5%) hypopituitarism, 18/82 (22%) colitis, 13/82 (16%) hepatitis, 4/82 (5%) arthritis, 1/82 (1%) encephalitis were reported. Melanoma pts had higher incidence of any grade irAEs compared to non-melanoma pts . Higher incidence of grade 3-4 irAEs were reported in pts who received 3mg/kg ipilimumab (41%) compared to 1mg/kg ipilimumab (28%), but not statistically significant.
Conclusion: There was a higher incidence of irAEs occurred in melanoma pts (especially hepatitis) and higher grade 3-4 irAEs were seen in pts receiving ipilimumab 3mg/kg. As more combined immunotherapy is more commonly used, vigilance to identify shifts in the prevalence of new toxicities will become required.