fizer has suffered a blow with the news that it has halted a late-stage study of the oncology agent Sutent in advanced breast cancer based on a “statistical assessment for futility”.

The company has discontinued the SUN 1107 Phase III study which evaluated Sutent (sunitinib) versus Roche's Xeloda (capecitabine) in patients with advanced breast cancer after failure of standard treatment. An independent Data Monitoring Committee found that even if the trial had been allowed to continue, Sutent would be unable to demonstrate a statistically significant improvement in the primary endpoint of progression-free survival compared to Xeloda.

Mace Rothenberg of Pfizer’s oncology business unit said the firm is disappointed especially given previous findings that suggested sunitinib “may provide benefit for patients with this difficult-to-treat cancer”. However he stressed that Pfizer remains committed to evaluating Sutent in advanced breast cancer both as a single agent and in combination with chemotherapy. Three other Phase III and two Phase II trials are ongoing.

Sutent, which had fourth-quarter sales of $220 million, is currently approved for both advanced renal cell carcinoma and second-line gastrointestinal stromal tumour. It is also being studied in Phase III trials as a treatment for cancers of the liver, colon and prostate, as well as for non-small cell lung cancer.

Recently, Pfizer called an early halt to a late-stage trial of Sutent after the therapy proved highly effective as a treatment for a rare form of pancreatic cancer.

Pipeline update
The Sutent announcement came just before Pfizer gave an R&D update, noting that it has 100 products currently in development. In the last six months, 26 programmes were discontinued, "15 as a result of strategic decisions made last year and 11 due to clinical attrition".

The company said that two new molecular entities have moved into Phase III – a first-in-class JAK inhibitor (CP-690,550), which is "the first orally-administered, disease-modifying antirheumatic drug for rheumatoid arthritis in 10 years", and tanezumab, a fully-humanised monoclonal antibody targeting nerve growth factor. The latter has been shown to significantly reduce pain in patients with osteoarthritis of the knee.

Two other Phase III products have been added to the pipeline, Pfizer noted, Dimebon (dimebolin) for Alzheimer's disease and Dupuytren's contracture therapy Xiaflex (clostridial collagenase), which are being developed in partnerships with Medivation and Auxilium, respectively.

Martin Mackay, head of Pfizer's Global R&D, said that "last year, we refined our approach to research by refocusing our pipeline to allow us to better select targets and molecules for development and move high-priority projects forward with improved cycle times".