February 18, 2009 — Rituximab should be used for maintenance therapy in patients with relapsed or refractory follicular lymphoma after successful induction therapy because it significantly improves survival.
This is the conclusion from a new meta-analysis of 5 trials, involving more than 1000 patients, published in the February 18 issue of the Journal of the National Cancer Institute.
"This meta-analysis demonstrates for the first time, to our knowledge, that rituximab maintenance therapy improves overall survival and disease control," say the researchers, headed by Liat Vidal, MD, from the Rabin Medical Center, in Petah-Tikva, Israel.
"Rituximab should be used for patients with relapsed follicular lymphoma after successful induction treatment," Dr. Vidal told Medscape Oncology. Such use is not currently recommended in guidelines, but many physicians are already doing this, she said.
Already Established in First-Line Treatment
Rituximab is already established in the first-line treatment of follicular lymphoma, for which it is often used in combination with chemotherapy. As reported by Medscape Oncology, a recent editorial in the Journal of Clinical Oncology (2008;26:4537-4538) said it was "time to declare a giant leap forward," because patients with follicular lymphoma are now living longer than ever and rituximab has been a major contributor to the progress that has been made in the treatment of this disease.
However, the question of what to do when a patient relapses or becomes refractory has not had a clear answer. Dr. Vidal and colleagues point out that individual trials exploring rituximab use in this situation have shown a prolongation of remission and of the progression-free interval, but have not yielded any clear evidence of an impact on overall survival. As a result, rituximab maintenance for follicular lymphoma is not recommended in treatment guidelines, such as those issued by the National Comprehensive Cancer Network, they point out.
Now, however, Dr. Vidal and colleagues have shown a clear survival advantage from the meta-analysis of 5 trials that they performed. The trials involved 1143 patients, but survival data were available for only 985 patients.
Patients who received rituximab maintenance had significantly better overall survival that those who did not (hazard ratio [HR] for death, 0.60; 95% confidence interval [CI], 0.45–0.79).
However, patients taking rituximab were twice as likely to have an infection-related adverse effect (HR, 1.99; 95% CI, 1.21–3.27), and some of the infections reported in these patients were life-threatening, Dr. Vidal and colleagues report. "The higher rate of infections should be taken into consideration when making treatment decisions," they say.
Survival Advantage Seen With Both Schedules
The 5 trials in the meta-analysis used various drug combinations and administration schedules, but the type of rituximab maintenance schedule had no effect on overall survival, the researchers note.
At the time when the clinical trials were initiated, rituximab was not yet established as a standard in first-line treatment, so some patients received it in their induction regimen and others did not. Some patients were treated with first-line rituximab alone, some with rituximab and chemotherapy, and some with chemotherapy alone.
In addition, the maintenance regimens varied. In 3 trials, rituximab was administered weekly for 4 consecutive weeks (4 doses) every 6 months, whereas in the 2 other trials, a single infusion of rituximab was administered every 2 to 3 months. The duration of treatment varied from 8 to 9 months to 2 years.
"Our results suggest that rituximab maintenance therapy for up to 2 years, either as 4 weekly infusions every 6 months or as a single infusion every 2 to 3 months, should be added to standard therapy of patients with relapsed or refractory follicular lymphoma after successful induction treatment," Dr. Vidal and colleagues conclude
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