Interleukin-2 therapy for refractory and relapsing lymphomas

Recombinant interleukin-2 (rIL-2) has been reported to be active in metastatic renal cell carcinoma and malignant melanoma. The purpose of this trial was to determine the efficacy and toxicity of rIL-2 administered in continuous infusion in patients with Hodgkin's disease (HD) and non-Hodgkin lymphoma (NHL). 21 patients with HD (4 patients), diffuse large-cell NHL (7) or low-grade NHL (10) in failure or relapse after multiple-conventional treatments were included in this trial. rIL-2 therapy consisted of an induction period of two cycles separated by 3 weeks of rest, and, in the absence of progressive disease or undue toxicity, a maintenance period of 4 monthly cycles. Each induction cycle comprised the continuous infusion of rIL-2: 18 × 10⁶ IU/m² per day on days 1–5 and days 12–16. Each maintenance cycle comprised the continuous infusion of rIL-2: 18 × 10⁶ IU/m² per day on days 1–5. Among the 21 treated patients, 5 (all of those with low-grade NHL) responded to the induction phase (1 complete response, 4 partial responses) and 2 patients had a mixed response. Conversely, no response was observed in patients with HD or large-cell NHL. The median duration of response was 4 months. rIL-2 administered as a continuous infusion was well tolerated and most patients received the full dosage, and management did not require intensive care. During the induction period, 2 patients experienced grade III cardiovascular or renal toxicity. During the maintenance period, rIL-2 had to be interrupted in 1 patient because of a myocardial infarction. This trial confirms the inefficacy of rIL-2 for the treatment of large-cell NHL and HD. Conversely, in low-grade NHL, rIL-2 activity needs to be explored by further studies. rIL-2 may have a place in the early phase of the disease, when the immune system is not compromised, as an adjuvant treatment in residual disease in order to improve the duration of response.