Safety of osimertinib in adult patients with metastatic epidermal growth factor receptor T790M mutation?positive non?small cell lung cancer: Results from a Phase IV study in India

ABSTRACT

Background: A Phase IV, single?arm study was conducted to assess the safety of osimertinib in Indian patients with epidermal growth factor receptor (EGFR) T790M mutation?positive stage IV non?small cell lung cancer (NSCLC). Methods: Enrolled patients received 80 mg osimertinib for six cycles or until disease progression or unacceptable toxicity or withdrawal. Primary safety variables included treatment?emergent adverse events (TEAEs), serious adverse events (SAEs), and adverse events (AEs) leading to discontinuation/interruption/change (D/I/C) of drug dose, and AEs of special interest (AESIs). AEs were summarized by the percentage of patients experiencing at least one occurrence of each event. Results: Of the 60 enrolled patients (median age 58 [range 34�] years; 51.7% women) at eight sites, nine patients were discontinued prematurely due to disease progression (n = 7) and death (n = 2); median (range) duration of treatment was 126 (1�4) days. Median age of patients was 58 (34�) years; 51.7% (n = 31) were women; 86.7% (n = 52) were nonsmokers; and most of them (98.3%) had adenocarcinoma. About 75% (n = 45) of patients experienced any of the TEAEs, with the most frequent being fatigue and creatine phosphokinase (CPK) increase (n = 6, 10% each). TEAEs in 11 (18.3%) patients were judged as study treatment related, with CPK increase being the most common (n = 4, 6.7%). TEAEs led to D/I/C of drug dose in eight (13.3%) patients, with one being study treatment related. Nine (15%) patients had AESIs of dyspnea (n = 6), chest pain (n = 2), and cardiorespiratory arrest (n = 1); two of them had a fatal outcome. One AESI (mild dyspnea) was considered study drug related. TEAEs of grade ?3 were reported in seven (11.7%) patients, including dyspnea in two (3.3%), followed by diarrhea, mucosal inflammation, cardiorespiratory arrest, and others (n = 1,1.7% each). None of the SAEs and fatal events were considered as study treatment related. Seven (11.7%) patients had abnormal electrocardiogram (ECG; not clinically significant) at the end of the study. Conclusion: Our study confirms the favorable safety profile of osimertinib without any new safety concerns in Indian patients with EGFR T790M mutation?positive stage IV NSCLC. ClinicalTrials.gov Identifier NCT03853551 CTRI registration no. CTRI/2018/10/015941