AE-941, a multifunctional antiangiogenic compound: trials in renal cell carcinoma

The therapy of renal cell carcinoma remains a challenge for medical oncologists and urologists. During the past 10 years, the molecular abnormalities occurring in various subtypes of renal cancer, such as clear cell renal carcinoma, have been well described. The genetic abnormalities found in clear cell tumours involve chromosome 3p and, additionally, hypermethylation of the von Hippel-Lindau (VHL) gene can be detected. The VHL protein is involved in the angiogenic cascade in non-hypoxic conditions, and the possible role of mutant or hypermethylated VHL protein in promoting angiogenesis is, therefore, of interest. The majority of patients with renal cell carcinoma who receive treatment, such as IL-2 and/or IFN, fail and develop progressive disease. Therapy is therefore inadequate and novel approaches, such as those inhibiting angiogenesis, are of interest. The agent AE-941 (Neovostat trade mark; AEterna) was developed based on the observation that shark cartilage may contain biologically active inhibitors of angiogenesis. A variety of in vitro and in vivo activities of this preparation have been identified. At the molecular level, AE-941 appears to exhibit four different potential mechanisms of action: modulation of matrix proteases; inhibition of vascular endothelial growth factor binding to its receptor; induction of endothelial cell apoptosis; and stimulation of angiostatin production. The antitumour effects of AE-941 are seen in multiple murine models and involve not only effects on primary tumour growth but also on development of metastases. AE-941 is administered orally and has an excellent toxicity profile. Of interest are the findings in patients with renal cell carcinoma. Preliminary trials in this setting have suggested that responses to AE-941 occur and that patients receiving higher doses of this agent may have improved survival. Based on these preliminary data, a large, multi-institutional, randomised, Phase III trial of this agent has now been conducted in patients with metastatic clear cell carcinoma of the kidney. Over 300 patients have been entered into this trial, accrual is complete and results still remain preliminary. The clinical studies in a malignancy such as renal cell carcinoma will provide sentinel and potentially important observations on the clinical effectiveness of this agent.