Multiple rechallenges with anti-PD-1 immunotherapy in patients with checkpoint inhibitor-related pneumonitis: A report of two cases

Introduction With the expanding use of immune checkpoint inhibitors (ICIs) in patients with various types of cancers, many more patients are experiencing checkpoint inhibitor-related pneumonitis (CIP). After recovery from CIP, some patients are rechallenged with ICI therapy. The CIP will recur in a considerable proportion of rechallenged patients. When severe or recurrent CIP (rCIP) occurs, ICI therapy is usually terminated, resulting to treatment failure and tumour progression. The feasibility of multiple rechallenges with immunotherapy in patients with rCIP is unknow. Case presentation Two patients with refractory classical Hodgkin lymphoma (cHL) were treated with anti-programmed cell death protein 1 (PD-1) immunotherapy. The lymphoma responded well to the ICI therapy, but both patients experienced CIP. The immunotherapy was suspended and steroid was introduced to treated the CIP. When the CIP resolved, however, the lymphoma progressed. Management and outcome The patients were rechallenged with anti-PD-1 immunotherapy in the absence of alternative treatment options. The lymphoma responded again, but the CIP recurred. The immunotherapy was suspended again and steroid was reintroduced. These episodes repeated multiple times. At the time of submission of this manuscript, the tumour in both patients has been controlled for more than 4 years, and the immunotherapy is still continuing. Conclusion Multiple rechallenges with immunotherapy is feasible in selected patients with rCIP.