Pneumonitis Associated with Immune Checkpoint Inhibitors and Targeted Anticancer Therapies: A Retrospective Case Series of 12 Patients

Background: Immunotherapy and targeted therapy have gained ground over conventional chemotherapy in treating various cancers. While pulmonary toxicity associated with these agents is rare, it represents a significant factor in both mortality and morbidity and may influence the overall success of cancer treatment. This case series report adds to the emerging evidence of cancer therapy-induced pneumonitis features and corticotherapy outcomes. Patients and methods: This single-center, retrospective case series analyzed 12 consecutive cases of patients undergoing immunotherapy (four receiving nivolumab, four receiving pembrolizumab) or targeted therapy (three receiving obinutuzumab, one receiving abemaciclib) for cancer (seven with lung cancer, three with non-Hodgkin lymphoma, one with breast cancer, one with renal cancer) who developed pneumonitis during their follow-up. Results: The interval from oncological treatment initiation to pneumonitis onset ranged from 6 to 48 months (median = 18.5), and in four patients it occurred after discontinuation of oncologic therapy. In most patients, the diagnosis was established with high probability based only on the clinical presentation, radiologic pattern, and concomitant oncologic therapy. Bronchoscopy with bronchoalveolar lavage analysis was performed in eight of the 12 patients, particularly when onset followed treatment discontinuation. The main symptom was dyspnea (10/12 cases), and three of 12 patients had respiratory failure (SpO2 ≤ 88%). The CTCAE severity grades were: one mild, seven moderate, three severe, and one life-threatening. The CT scan showed different patterns (7 OP, 4 NSIP-like, and 1 HP). Eleven patients received oral methylprednisolone (0.40 to 0.82 mg/kg) for 5 to 16 weeks. Two patients continued oncologic treatment, and six discontinued. Pneumonitis improved or resolved in 11 of the 12 patients; one patient deteriorated after reintroduction of immunotherapy and subsequently died from cancer-related complications. Conclusions: Immunotherapy- and targeted therapy-induced pneumonitis can express various features and severities, and prompt recognition and diagnosis based on clinical, radiologic and contextual elements are mandatory. In this small, heterogeneous series the individualized corticosteroid regimens used were followed by favorable outcomes. Our observations suggest that, in selected clinically improving patients, follow-up may rely only on clinical assessment and chest X-ray, and extensive tests may be reserved for non-responsive cases.