A pilot study of suramin in the treatment of progressive refractory follicular lymphomas

Ten patients with progressive follicular lymphomas (seven with follicular mixed lymphomas, three with follicular, small cleaved cell lymphomas) with clinical indications for systemic therapy received parenteral suramin. Each had failed from one to six prior chemotherapeutic regimens and three had in addition received prior radiation therapy. All had measurable disease and nine of the ten had documented bone marrow involvement at the start of therapy. Suramin was administered at an initial infusion rate of 350 mg/m2/day, which was then modified on the basis of subsequent weekly plasma suramin concentrations in order to reach a final plasma concentrations of 250-350 micrograms/ml. Treatment cycles were repeated at eight week intervals. Nine of ten patients are evaluable for response. Five of nine evaluable patients achieved a partial remission as defined by a greater than 50% decrease in the sum of the product of all measurable lesions. Sites of response include: Peripheral (five patients) and central (four patients) adenopathy, disappearance of biopsy-proven skin involvement (one patient), malignant pleural effusions (one patient) and shrinkage of an enlarged spleen (two patients). Disappearance of B symptoms occurred in the one responder with these symptoms. Response duration varied from 3 to 9 months (mean 5.6 months) with time to subsequent systemic therapy varying from 5 to 12 months (mean 8 months). Drug related toxicity included the development of polyradiculopathy (one case), liver function abnormalities (three cases), thrombocytopenia (five cases), vortex keratopathy (two cases) and bacterial infection (two cases). We conclude that suramin has significant activity against follicular lymphomas refractory to standard chemotherapy and that its precise role in the treatment of lymphoproliferative neoplasms in general warrants further investigation.