HOUSTONHigh-dose chemotherapy (HDCT) plus rituximab
(Rituxan) produces responses comparable to HDCT with total body irradiation and
stem cell transplant for aggressive mantle cell lymphoma (MCL), according to
Jorge E. Romaguera, MD, of the University of Texas M. D. Anderson Cancer Center
in Houston, Texas. In a poster presentation, Dr. Romaguera said that HDCT with
rituximab (but without total body irradiation or stem cell transplant) produced
a complete response (CR) rate of 86%.
The failure rate at 9 months median follow-up was comparable to
that observed with stem cell transplant (6% vs 4%) and much better than the 50%
failure rate seen with historical CHOP (cyclophosphamide, doxorubicin, Oncovin
[vincristine], prednisone) controls, he added.
"Patients with mantle cell lymphoma have a poor prognosis.
Anthracycline-containing chemotherapeutic regimens typically provide low
response rates with only 21% complete response, a short median response
duration of 10 months, and dismal survival rates of 2 to 4 years," Dr.
Romaguera said. "A recent CHOP-like regimen of hyperfractionated
cyclophosphamide, doxorubicin, vincristine, and dexamethasone [HCVAD]
alternating with high-dose methotrexate [M] and cytarabine (Ara-C) [A] and
consolidated after four courses with high-dose cyclophosphamide, total body
irradiation, and autologous blood or marrow stem cell transplantation can
achieve 100% CR."
In this earlier study, seven patients did not receive
transplant because of financial reasons, inability to harvest stem cells, or
refusal. Instead, they received up to eight cycles of HCVAD/M-A, which produced
an 86% CR rate with comparable time to progression.
Encouraging Results
"Because of this, we are currently investigating eight
alternating cycles of HCVAD/M-A in previously untreated patients but without
consolidation unless a CR is not achieved after the first six cycles of
treatment," Dr. Romaguera said. "We have included rituximab at 375
mg/m2 given 24 hours before each of the first 6 cycles of therapy." (See
Figure 1.) The dose of cytarabine was limited to 1 g/m2/dose in patients over
age 60 or those having elevated serum creatinine levels.
Patients were restaged at the end of the first two cycles of
therapy. In the case of CR, patients were given four more cycles of therapy. In
the case of partial response (PR), patients were given six more cycles of
therapy. If patients were still in PR after six cycles of therapy, they were
taken off study and offered stem cell transplantation.
Prophylactic granulocyte-colony stimulating factor (G-CSF),
fluconazole (Diflucan), valacyclovir (Valtrex), and levofloxacin (Levaquin)
were given on days 8-17 in cycle 1 and days 5-14 of cycle 2.
Data on 49 evaluable patients were reported, including 37 who
completed six cycles of therapy. Dr. Romaguera reported a CR rate of 86%, an
11% PR rate, and 3% failures. "HCVAD/M-A with rituximab achieves a high
rate of complete remission," he said. "Hematologic toxicity was
severe, but only 8% of patients had grade 3 infections according to NCI
criteria. These results are encouraging and the trial continues to accrue
patients."
