Cancer drug developer Antisoma plc announced that it has started a phase-II study of AS1411 in metastatic renal cell carcinoma (kidney cancer).

The single-arm trial will enrol around 30 patients intolerant to, or having relapsed after, previous treatments including a tyrosine kinase inhibitor (sunitinib or sorafenib). It will evaluate the safety and efficacy of AS1411 monotherapy given at 40 mg/kg/day for four days every 28 days for up to two cycles. Efficacy measures in the trial include response rates, time to progression and progression-free survival. Final results are expected in 2010.

Dr Jonathan Rosenberg of the Dana-Farber/Harvard Cancer Center, Boston, MA, an investigator in the trial, said, "AS1411 showed an excellent safety profile and promising signs of activity in renal cell carcinoma patients in phase-I testing, and so we're delighted to be involved in further evaluating its potential in this setting. While a number of new therapies are now available, advanced kidney cancer remains an incurable illness in the large majority of patients, and there is still a clear unmet need to improve treatments available to these patients."

The phase-I trial of AS1411 included 12 patients with renal cell carcinoma. Eleven showed at least stabilisation of their disease. Of these, two had objective responses, including one complete response. A phase-II trial of AS1411 in acute myeloid leukaemia was initiated last year and recently reported promising preliminary findings.

Antisoma's chief executive officer, Glyn Edwards, commented, "Evidence to date suggests that AS1411 has broad potential against blood cancers and solid tumours. With phase II trials now ongoing in both acute myeloid leukaemia and kidney cancer, we are testing AS1411 in diverse settings, and look forward to the roll-out of clinical data over the next two years."

Aptamers are short pieces of DNA or RNA that can fold into stable, three-dimensional structures capable of interacting with particular target proteins. AS1411 is the first aptamer to be tested as a treatment for cancer.

Antisoma is a London Stock Exchange-listed biopharmaceutical company that develops novel products for the treatment of cancer.