- Patients who have had chemotherapy within 4 weeks, rituximab within three months (unless there is evidence of progression) or radiotherapy within 2 weeks or those who have not recovered from adverse events due to agents administered more than 4 weeks earlier are excluded; this does not include use of steroids, which may continue until two days prior to enrollment; low dose chlorambucil should be stopped two weeks prior to beginning SAHA; valproic acid should be stopped at least two weeks prior to enrollment; nitrosoureas and mitomycin should be stopped 6 weeks prior to enrollment