Swiss drug maker Novartis AG said at an investor conference that the U.S. Food and Drug has requested more data on Afinitor (everolimus or RAD 001), the company’s advanced kidney cancer drug, but no additional studies. The regulator decision postponed –according to Novartis- by at least three months the approval of the promising treatment.

Afinitor belongs to the mTOR class, the same family of Wyeth’s Torisel (temsirolimus), kidney cancer drug approved last year. Future competition also includes Pfizer’s Sutent (sutinib) and Bayer/Onxy Pharma’s Nexavar (sorafenib).

Torisel earned $87 million the first nine month of the year, while Sutent and Nexavar gather $627 million and $499 million, respectively.

So far, analysts consider Afinitor data really impressive. For example, at the American Society of Clinical Oncology this year, Novartis presented a 400 patient clinical trial:

Of 400 people with kidney cancer, 272 were given everolimus, while 138 were given placebo

After six months, tumors had not grown or spread in 26 percent of patients who got everolimus, compared to 2 percent of the placebo group.

On average, patients on everolimus enjoyed four months of so-called progression-free survival compared to just under two months for those who got the placebo.

Independent monitors who watched the drug trials were so impressed by the results that
they stopped the trial last February so everyone could be put on everolimus.