Meta-analysis to evaluate the role of interferon in follicular lymphoma

Purpose To determine whether interferon (IFN)-alpha 2, when given with or following chemotherapy, influences response rate, remission duration, and survival in newly diagnosed patients with follicular lymphoma. Patients and Methods Ten phase III studies evaluating the role of IFN-alpha 2 in 1,922 newly diagnosed patients with follicular lymphoma were analyzed. Updated individual patient data were used to perform meta-analyses for response, survival, and remission duration. Results The addition of IFN-alpha 2 to initial chemotherapy did not significantly influence response rate. An overall meta-analysis for survival showed a significant difference in favor of IFN-alpha 2, but also showed significant heterogeneity between studies. Further analyses were carried out in order to explain this heterogeneity, and to define the circumstances in which IFN-alpha 2 prolonged survival. The survival advantage was seen when IFN-alpha 2 was given: (1) in conjunction with relatively intensive initial chemotherapy (2P = .00005), (2) at a dose >= 5 million units (2P = .000002), (3) at a cumulative dose >= 36 million units per month (2P = .000008), and (4) with chemotherapy rather than as maintenance therapy (P = .004). With regard to remission duration, there was also a significant difference in favor of IFN-alpha 2, irrespective of the intensity of chemotherapy used, IFN dose, or whether IFN was given as a maintenance strategy or with chemotherapy. Conclusion When given in the context of relatively intensive initial chemotherapy, and at a dose >= 5 million units (>= 36 x 10(6) units per month), IFN-alpha 2 prolongs survival and remission duration in patients with follicular lymphoma. (c) 2005 by American Society of Clinical Oncology.