Inclusion Criteria:

- Patients must have histologically and clinically confirmed relapsed and/or refractory
low grade follicular B cell NHL (follicular small cleaved cell, follicular mixed
small and large cell, and small lymphocytic lymphoma (according to the IWF
classification); the malignant tissues must be positive for CD 20 on
immunohistochemistry or flow cytometry

- History of one or multiple prior chemotherapy regimens for low grade follicular NHL,
but no more than 4 therapies

- For the phase II trial: previous therapies can include rituximab, fludarabine
(alone not in combination or sequentially); the most recent therapy should be
completed more then 4 weeks prior to protocol entry, 6 months if the last
regimen included Fludarabine, rituximab, nitrosoureas or mitomycin, and at least
8 weeks out from a treatment with UCN-01

- For phase I trial: Patients can move from phase II to phase I trial if they have
not received rituximab and fludarabine in combination or sequentially in the
past, if they received one or both agents individually and had a 50% responses;
this response corresponds to PR to prior therapy

- Presence of measurable disease by CT scan 4 weeks after the last chemotherapeutic
regimen with at least one lesion greater than 1.5c m in one dimension and or positive
bone marrow biopsy

- ECOG performance status ≤ 2 with a minimal life expectancy of 4 months

- Female patients of childbearing age should have negative pregnancy test; pregnant and
breast-feeding women will not be eligible for the study because the antiproliferative
effects of depsipeptide may be harmful to the developing fetus or nursing infants

- Absolute neutrophil count >= 1000/µl; lower ANC (>= 500/µl) count will be considered
if they are due to a bone marrow involvement by the disease; patients can receive
growth factors (G-CSF and erythropoietin) to sustain the peripheral counts during the
cycles of therapy

- Platelets >= 100.000/µl; lower platelets (>50.000/µl) count will be considered if
they are due to a bone marrow involvement by the disease; patients can receive growth
factors (G-CSF and erythropoietin) to sustain the peripheral counts during the cycles
of therapy

- Total bilirubin =< 1.5 x institutional upper limit of normal

- AST/ALT =< 3 x institutional upper limit of normal

- Creatinine =< 1.5 x the institutional upper limit of normal

- Patients with history of seizures are included if under adequate control; blood
levels of seizure medications are monitored during the study

- The patient must understand the investigational nature of the protocol, potential
risks and benefits of the study and provides an informed written consent form

Exclusion Criteria:

- Patients who have had chemotherapy or radiotherapy within 4 weeks (within 6 weeks for
rituximab, nitrosoureas and mitomycin and within 8 weeks for UCN-01) prior to
entering the study or those who have not recovered from adverse events due to agents
administered more than 4 weeks earlier

- Patients who had prior treatment with depsipeptide or any other histone deacetylase
inhibitor

- Patients who had prior allogeneic stem cell transplantation

- Bulky disease: single mass greater than or equal to 10 cm

- Patients may not be receiving any other investigational agents

- Patients with known CNS involvement (as documented by MRI and or cerebro-spinal fluid
examination) should be excluded from this clinical trial because of their poor
prognosis and because they often develop progressive neurological dysfunction that
would confound the evaluation of neurological and other adverse events

- History of life threatening allergic reactions attributed to agents used in the study

- Impaired cardiac function: history of life threatening arrhythmias, MI within the
preceding 6 months, severe CAD, cardiomyopathy, congestive heart failure >= NYH II;
EF =< 40%; EKG abnormality i.e.: ischemic ST-T abnormalities, QT prolongation,
pathologic q waves, arrhythmias (except for benign PAC's and PVC's, 1st degree AV
block, 2nd degree AV block Wenkebach); patients with LVH on EKG will be ineligible
for this trial

- Patients with prior malignancies other then basal cell carcinomas and cervical
intra-epithelial neoplasia

- Patients (or their partners) unwilling to use contraception

- Patients who require pharmacological doses of corticosteroids for intercurrent
medical conditions

- Patients who uses concomitant drugs which may cause a prolongation of QTc