BUFFALO, New York-Median
progression-free survival has
still not been reached after 6 years
median follow-up of 40 patients
with low-grade or follicular non-Hodgkin's lymphoma (NHL) treated
in the first clinical trial of
rituximab (Rituxan) in combination
with CHOP (cyclophosphamide
[Cytoxan, Neosar], doxorubicin
HCl, vincristine [Oncovin],
and prednisone), Myron S.
Czuczman, MD, reported.
In a poster presented at the 43rd
Annual Meeting of the American
Society of Hematology (abstract
2519), Dr. Czuczman reported that
38 patients received treatment and
were evaluable for efficacy, 35 of
whom had received all six infusions
of rituximab and six cycles of
CHOP. Two patients were enrolled
in the trial but not treated. CHOP
was administered at standard doses
every 3 weeks for six cycles along
with six infusions of rituximab (375
mg/m2/dose). Two doses of
rituximab were given both at the
beginning and end of therapy, as
well as single doses before the third
and fifth cycles of CHOP.
Dr. Czuczman said that the overall
response rate using intent-totreat
analysis was 95% (55% complete
response [CR], 40% partial
response [PR]). In patients who
completed all therapy the response
rate was 100% (63% CR, 37% PR).
"The median duration of response
and progression-free survival
have not been reached after 63.6+
and 65.1+ months of observation,
respectively," Dr. Czuczman reported.
"Twenty-one patients are still in
remission at 46.8+ and up to 86.3+
Of eight patients who were bcl-2
positive, seven had molecular complete
remissions (converted to polymerase
chain reaction [PCR] negativity
in blood and marrow). Three
of these patients remain PCR negative
and in CR at 71+, 79+, and 84+
months. Four patients converted to
negative and then reverted to positive.
Three of these patients remain
in CR at 68+, 81+, and 86+ months,
and one developed progressive disease
at 29 months.
Combination Therapy Is Safe
Adverse events were mostly grade
1 or 2. Seventeen percent of all events
were grade 3 or 4 and consisted primarily
of hematologic or infectious
toxicities felt to be associated with
CHOP chemotherapy. Human
antichimeric antibody responses
were not seen.
The only prognostic factor significantly
associated with achieving
a CR vs a PR was lesion size.
"Rituximab plus CHOP results in
a high response rate and a prolonged
progression-free survival. Combination
therapy is safe and does not cause
significant added toxicity. Conversion
of bcl-2 from positive to negative
by PCR in blood and marrow
indicates clearance of minimal residual
disease. The prolonged progression-
free survival exceeds that reported
in studies of CHOP alone,"
Dr. Czuczman said.