Interferon-α2b in the treatment of follicular lymphoma: Preliminary results of a trial in progress

Since 1985 the combination of chlorambucil (10 mg daily, initially for six weeks, then alternating fortnights for 12 weeks) and interferon-α2b (Schering-Plough; 2 × 106 U/m2 three times weekly by subcutaneous injection for 18 weeks) has been compared in a randomised trial with chlorambucil alone in previously untreated patients with stage III or IV follicular lymphoma. Responding patients have subsequently been randomised to receive maintenance interferon-α2b or no further treatment. Of the 124 treated patients, 108 are evaluable for response with a median follow-up of 30 months. The major toxicity was myelosuppression which was more frequent with chlorambucil and IFNα2b in combination than with chlorambucil alone (P < 0.01). There was no treatment-related mortality. Actuarial survival at three years is 75% for all patients, regardless of therapy. There was no significant difference in response rate according to initial therapy. For the 60 patients achieving a good response to initial therapy who have entered the second part of the trial, there has been a significant prolongation of remission duration in favour of maintenance IFN-α2b (median not yet reached versus two years for the 'no treatment' arm, P < 0.015). Fewest relapses have been seen in patients who received IFN-α2b throughout. Accrual to this trial continues; this preliminary analysis indicates that maintenance IFN-α2b may extend remission duration in follicular lymphoma.