Ribociclib-induced steroidrefractory pneumonitis: a case report

Introduction: Ribociclib is a CDK4/6 inhibitor that has revolutionized the treatment of HER2-negative, hormone receptor-positive breast cancer. In combination with aromatase inhibitors, it has significantly improved progression-free survival and decreased risk of death by 28%. From the MONALEESA trial, the most common adverse effects of the drug include leukopenia, transaminitis, and GI toxicity reported in > 2% of patients. While there have been case reports of other CKD 4/6 inhibitors causing pneumonitis, there is scant literature of ribociclib-induced pulmonary toxicity. Here, we present a case of ribociclib-induced pneumonitis, unresponsive to high-dose steroids. Description: A 67-year-old female with a history of metastatic ER+/HER2- breast cancer presented to MD Anderson with dyspnea after completing a course of Ribociclib a week prior. She became febrile and required increased respiratory support with BiPAP. Cultures (fungal/bacterial) and respiratory viral panel remained negative. CT-Chest was performed and demonstrated suspicion of drug-induced lung injury and empiric steroid therapy was initiated. Despite treatment, the patient decompensated and high-dose steroids were started while she was intubated. After 1-2 weeks of treatment with minimal symptomatic improvement, GOC discussion was held, and the patient received a tracheostomy. Care was withdrawn 19 days after admission. Discussion: Ribociclin-induced pneumonitis has been rarely described, with 2/3 case reports responding well to steroids. In patients that receive prolonged courses of high-dose steroids without improvement, alternative therapies such as infliximab and IVIg should be considered. After intubation, early and daily CPAP trials should be performed to avoid diaphragmatic deconditioning from mechanical ventilation. It is important to highlight fatal adverse effects of novel cell therapeutics, especially ones with significant survival benefits, for early recognition and management. Further research is warranted to identify the most appropriate management approach for such toxicities.