Pemetrexed-related interstitial lung disease reported from post marketing surveillance (malignant pleural mesothelioma/non-small cell lung cancer)

Background: Interstitial lung disease (ILD) is important drug related toxicity because it commonly forced to discontinue the treatment. Methods: To characterize the prevalence and patterns of pemetrexed induced ILD, an independent ILD advisory board composed of external experts performed reassessment of ILD in two post marketing surveillance (PMS) studies for malignant pleural mesothelioma (MPM) and non-small cell lung cancer (NSCLC). Results: ILD incidences were originally 1.6% and 2.6% in 903 MPM and 683 NSCLC patients in safety analyses, respectively. Based on the reassessment by the board, the incidence was 1.1% MPM and 1.8% NSCLC. Common possible risk factors of ILD in MPM and NSCLC patients were male gender, 60 years or older age, and pre-existing ILD. Asbestosis in MPM, and smoking history in NSCLC are also considered as risk, respectively. In terms of computed tomography (CT) pattern, 7 of 10 cases in MPM patients had acute interstitial pneumonia pattern, which four were fatal. Eight of the 12 NSCLC patients had diffuse grand glass opacity, which all had recovered. Onset of ILD in MPM varied between the first and the fifth courses of pemetrexed treatment, and the latest onset was 48 days after the last administration. For NSCLC, it was between the second and the ninth course, 7 and 56 days after the last administration. Conclusions: The risk of pemetrexed-related ILD is similar level as other anti-cancer drugs under clinical settings. Careful observations continuously during and at least for 2 months after the last administration of pemetrexed are advised.