Dl. Longo et al., Combination chemotherapy followed by an immunotoxin (anti-B4-blocked ricin) in patients with indolent lymphoma: Results of a phase II study, CANCER J, 6(3), 2000, pp. 146-150
The purpose of this article was to evaluate the antitumor effects of a comb
ination chemotherapy program based on ProMACE (prednisone, methotrexate, do
xorubicin [Adriamycin], cyclophosphamide, etoposide) followed by a B cell-s
pecific immunotoxin in the treatment of patients with advanced-stage indole
nt histology non-Hodgkin's lymphomas. We performed a prospective phase II c
linical trial in a referral-based patient population. After confirmation of
diagnosis and staging evaluation, 44 patients (10 small lymphocytic lympho
ma, 27 follicular lymphoma, 7 mantle cell lymphoma; 30 without prior therap
y, 14 previously treated) received six cycles of ProMACE-CytaBOM (cytarabin
e, bleomycin, vincristine [Oncovin], mechlorethamine) combination chemother
apy (with etoposide given orally daily for five days) followed by a 7-day c
ontinuous infusion of anti-B4-blocked ricin immunotoxin at 30 mu g/kg/day g
iven every 14 days for up to six cycles. A complete response was achieved i
n 25 of 44 patients (57%), 21 from the chemotherapy alone, 3 converted from
partial to complete response with the immunotoxin, and 1 patient became a
complete responder after a surgical procedure to remove an enlarged spleen
that was histologically negative for lymphoma. With a median follow-up of 5
years, 14 of 25 complete responders have relapsed (56%); median remission
duration was 2 years, and overall survival was 61%. Forty-two percent of th
e complete responders have been in continuous remission for more than 4 yea
rs. The median number of courses of immunotoxin delivered was two usually b
ecause of the development of human anti-ricin antibodies. ProMACE- CytaBOM
plus anti-B4-blocked ricin does not produce durable complete remissions in
the majority of patients with indolent lymphoma. However, the remissions ap
pear quite durable (> 4 years) in about 40% of the complete responders.