Severe irAEs in patients with immune checkpoint inhibitor therapy: Experience in a Mexican cancer center.

Abstract

e14559 Background: A relationship has been found between a better response to treatment and the presence of irAEs. Different potential factors for developing them have been described, including the type of immunotherapy and their combination. Rare (< 1%) and potentially life-threatening irAEs have been reported, which due to severity lead to treatment discontinuation, and a prolonged effective response is seen in these patients if they survive the irAE. Methods: Observational study in patients with solid tumors who received treatment with immune checkpoint inhibitor and their characteristic, that presented irAEs grade 3 and 4 using the CTCAE version 4, from January to December 2021 in a Mexican cancer center. Results: irAEs grade 3 or 4 were observed in 7 (5.6%) of 125 patients, with an age range of 60 to 69 years, most of the patients had a diagnosis of metastatic melanoma (43%) and secondly urothelial carcinoma with 29%. The predominant treatment was pembrolizumab monotherapy (56%), with an average of 5 applications after those who presented irAEs. The rare irAEs presented were myocarditis (2.4%), myositis (1.6%), myasthenia gravis and interstitial nephritis, both with 1%. 70% of these patients were managed with three boluses of methylprednisolone and subsequently prednisone 1 mg/kg as maintenance. The median appearance of these irAEs was 72 days. Myocarditis and myositis had an earlier onset with an average of 32 days. One of the seven patients presented myasthenia gravis, myositis and myocarditis concomitantly, with complete response of the neoplasia, however, due to the prolonged use of immunosuppressants to control irAEs, the disease recurred at 7 months. Two of the three patients with myocarditis had a complete response and remain disease free. 57% survived more than 90 days, of which 75% are still alive. Conclusions: Among the 125 patients who received an immune checkpoint inhibitor in our cancer center in 2021, the most prevalent serious irAE was myocarditis, with a higher incidence than that reported by other centers, and a prolonged therapeutic response was found in the patients who presented it.