Treatment of lymphoid cell malignancy with In-114m labelled autologous lymphocytes

This paper is a preliminary report of a clinical trial for the treatment of patients with refractory chronic lymphocytic leukaemia, using autologous In-114m-labelled lymphocytes. Fourteen patients have been treated so far with doses ranging from 69 to 211 MBq. All patients had progressive low grade NHL, resistant to chemotherapy and conventional radiotherapy. Following the intravenous administration of radiolabelled autologous lymphocytes 53% (range 33-92%) of the activity accumulated in the spleen, 35% (21-64%) in the liver and 5% in the bone marrow. The initial response in all patients was a rapid decrease in lymphocyte count in peripheral blood. 10 of the 14 (72%) patients showed a response to the treatment. In 2 patients, there was a complete response which lasted 24 and 36 months respectively, 8 patients showed a partial response of 2 to 17 months duration. None of the patients experienced any subjective toxicity although myelosuppression was seen in all patients. This is a novel concept for the administration of therapeutic radiation in a selective way for the treatment of lymphoid cell malignancy and has produced significant antitumour effect in patients with highly resistant disease. The trial is ongoing and a full report will be published on its completion.