Inclusion Criteria:

- Patients with relapsed or refractory indolent B-cell non-Hodgkin's lymphoma or
peripheral T-cell lymphoma

- Indolent B-cell lymphoma will include Waldenström's macroglobulinemia,
lymphoplasmacytoid lymphoma small lymphocytic lymphoma, marginal zone lymphoma,
and follicular small cleaved-cell or mixed cell lymphoma; patients with prior or
concurrent evidence of transformation to large cell lymphoma or with follicular
large cell lymphoma are ineligible

- Peripheral T-cell lymphoma will include all entities described in the REAL
classification; patients with B-cell ALCL are ineligible; patients with
cutaneous T-cell lymphoma and all its variants and/or histologic transformation
of cutaneous T-cell lymphoma are not eligible for this protocol, because they
will be instead eligible for a separate protocol

- Relapsed peripheral T-cell lymphomas include all those achieving and maintaining
a complete or partial response during initial therapy; refractory includes those
achieving all other responses during initial therapy; since the response rate of
indolent B-cell lymphomas to up-front therapy exceeds 90% this distinction is
not meaningful there

- No more than 2 prior chemotherapy and one prior immunotherapy regimens; if
chemoimmunotherapy was used, the limit will be 3 prior regimens

- Performance status =< 2 Zubrod

- Staging work-up within 3 weeks and bidimensionally measurable disease

- No anti-cancer treatment within the past three weeks

- ANC >= 1,000/ul; may be included if in the judgment of the study chairman lower
counts are explained by marrow or splenic involvement by lymphoma

- Platelets >= 100,000/ul; may be included if in the judgment of the study chairman
lower counts are explained by marrow or splenic involvement by lymphoma

- Bilirubin =< 1.5 x normal

- SGPT =< 2.5 x normal values

- Estimated endogenous creatinine clearance > 50 ml/min

- HIV negative; the patients are excluded because the expected opportunistic infections
will render study toxicity difficult to interpret; in addition the possible effects
of 506U78 on CD4 cells may be dangerous to these patients; furthermore, indolent
B-cell lymphomas and aggressive peripheral T-cell lymphomas are extremely rare in the
setting of HIV infection

- No active CNS disease

- No other malignancy within the last 5 years, except basal cell carcinoma of the skin
or in-situ cervical carcinoma treated with curative intent

- Females must not be pregnant or breast feeding and must be practicing adequate
contraception; this is because 506U78 may be harmful to the developing fetus and
nursing newborn or infant

- No preexisting sensory or motor neuropathy of grade ≥ 2, no history of seizures

- No prior stem cell or bone marrow transplantation; no prior 506U78

- All patients, including women or members of a minority that fulfill criteria for
study entry will be eligible for treatment; no one fulfilling all these criteria for
entry will be denied treatment solely on the basis of sex or minority status

- Patients with medical, psychiatric, or social conditions that make compliance with
treatment or follow-up unlikely are not eligible

- No history of symptomatic cardiac dysfunction or pericardial effusion