Has a history of (noninfectious) pneumonitis that required steroids or has current pneumonitis. Has evidence of active, noninfectious pneumonitis that requires treatment with steroids Has a history of (noninfectious) pneumonitis that required steroids or has current pneumonitis History of (noninfectious) pneumonitis that require steroids or current pneumonitis Has evidence of active, noninfectious pneumonitis that required treatment with steroids History of (noninfectious) pneumonitis that required systemic steroids or current pneumonitis/interstitial lung disease. Patients who have evidence of active, noninfectious pneumonitis or have a history of severe pneumonitis that required treatment with steroids are not eligible for this study Patients with a history of noninfectious pneumonitis will be excluded during the dose-escalation phase of the trial Has a history of (noninfectious) pneumonitis that required steroids or has current pneumonitis Has evidence of noninfectious pneumonitis that required steroids or current pneumonitis. History of (noninfectious) pneumonitis that required steroids or current pneumonitis. Patients who have evidence of active, noninfectious pneumonitis or have a history of severe pneumonitis that required treatment with steroids are not eligible for this study; (Note: replacement physiologic dose of steroids [prednisone mg daily or equivalent] are allowed) History of (noninfectious) pneumonitis that required steroids or current pneumonitis History of noninfectious pneumonitis History or evidence of active, noninfectious pneumonitis that required treatment with steroids EXCLUSION CRITERIA FOR CROSSOVER THERAPY: History or evidence of active, noninfectious pneumonitis that required treatment with steroids