<qa>  What is the exception to the Known active central nervous system metastases?14. Known active central nervous system CNS metastases andor carcinomatous meningitis. Exception: Subjects with previously treated brain metastases may participate provided they are stable without evidence of progression by imaging, for at least 4 weeks prior to the first dose of study drug and any neurologic symptoms have returned to baseline, have no evidence of new or enlarging brain metastases, and are not using steroids for at least 7 days prior to trial treatment. This exception does not apply to carcinomatous meningitis which is excluded regardless of clinical stability. 