Background: Drug-induced interstitial lung disease (ILD) is one of the most serious adverse reactions associated with the molecularly targeted drugs. Panitumumab has been approved for advanced or recurrent colorectal cancer. Although there were no adverse reaction reports of ILD in panitumumab monotherapy, 4 cases in combination chemotherapy were reported prior to its approval in Japan in 2010. Several studies also reported that the incidence of drug-induced ILD was higher in Japan than in other countries. The clinical features of ILD and the associated risk factors therefore need investigation.
Methods: We analyzed the data from 3085 unresectable, advanced or recurrent colorectal cancer patients enrolled in a postmarketing all-case surveillance study of panitumumab in Japan. ILD case reports were assessed based on the clinical and radiologic findings by a committee of external experts. Multivariate analysis using Cox's hazard model identified the risk factors.
Results: ILD incidence (1.3 %) and mortality rates (51.3 %) were similar to those of patients receiving another anti-epidermal growth factor receptor (EGFR) monoclonal antibody in Japan. No specific onset timing was determined. Although panitumumab-specific ILD findings were not observed in computed tomography images or clinical practice, panitumumab can induce ILD with diffuse alveolar damage, as do the other anti-EGFR targeting drugs. A history/complication of ILD, male sex, poor general condition, and 65 years or older were identified as ILD risk factors, and no history of previous drug treatment was an apparent risk factor.
Conclusion: Panitumumab-induced ILD can occur at any time after initiation, and close and regular monitoring is needed.
Keywords: Colorectal cancer; Interstitial lung disease; Panitumumab; Postmarketing surveillance; Risk factors.