Anticancer agent — suramin sodium
Suramin has long been used to treat parasitic infestations. It had significant side-effects and is not orally available, so has to be given intravenously. Recently it has been shown to have potential as a form of chemotherapy for treating advanced hormone refractory prostate cancer. Suramin was found to induce adrenal insufficiency, and this appeared to affect the growth factors involved in prostate cancer cell growth.
The efficacy and toxicity of high doses of suramin plus hydrocortisone were assessed in patients with hormone refractory prostate carcinoma.1 Subjects were given a bolus intravenous infusion of 200mg/m2 suramin followed by 500mg/m2 of the drug intravenously over 24h, given daily over five days as a loading course, and then 350mg/m2 over 2h administered weekly for 12 weeks. This 12 week course was repeated at six month intervals, and patients received concomitant hydrocortisone. The median duration of response was 15.5 weeks, the time to disease progression 13 weeks, and overall survival time 11 months. Treatment was generally well tolerated, with fatigue and severe lymphopoenia the most commonly reported toxicities.
In another randomised study to assess dose dependence of the drug's efficacy and toxicity, 390 patients were given low, medium or high dose suramin (with total doses of 3.192, 5.32 and 7.661g/m2 respectively).2 Median survival time was 16 months for those on the low dose regimen, 14 months for the medium group, and 13 for those given the highest dose. The modest toxicity experienced by patients in the low dose regimen meant this was the preferred arm on this study, and the lack of dose–response relationship and toxicity profile observed raise questions about the utility of high-dose suramin as administered on this schedule.