Novartis AG’s kidney-cancer drug Afinitor also prevented breast cancer from worsening in a study that the Swiss drugmaker plans to use in applying for regulatory approval.Among women with breast tumors that had spread after treatment, Afinitor more than doubled the time until their disease worsened compared with those who only got Pfizer Inc.’s Aromasin, according to results presented at a cancer conference in Stockholm today. The trial was stopped early because the primary goal was met earlier than expected.“This could be game-changing,” Jose Baselga, a Harvard Medical School professor and chief of hematology and oncology at Massachusetts General Hospital who led the study, said in an interview. “I don’t recall a study in this patient population that had this magnitude of an effect. It’s pretty exciting.”The findings move Novartis closer to marketing Afinitor for a fourth tumor type. The Basel-based company plans to apply for regulatory approval this year to sell Afinitor as a breast cancer treatment, and expects it to be on the market in the U.S. and Europe by the end of next year.That would add more than $1 billion to annual sales over time, Herve Hoppenot, president of the company’s cancer division, said in an interview in Stockholm.European regulators are likely to approve the drug for breast cancer based on today’s result, said Tim Race, an analyst at Deutsche Bank AG in London who rates Novartis shares “buy.” The U.S. Food and Drug Administration may want to see longer- term data on whether Afinitor prolongs survival, he said.An FDA advisory committee voted in June in favor of withdrawing marketing approval for Roche Holding AG’s Avastin in breast cancer after longer-term studies showed the drug increased side effects and didn’t prolong survival compared with chemotherapy.“That’s why the market’s going to be a little bit careful with this data, and not price it in fully until they see a regulatory approval,” Race said in a telephone interview today.Novartis rose 2 percent to 49.47 Swiss francs as of 12:08 p.m. in Zurich trading, compared with a 1.9 percent gain in the Bloomberg Europe Pharmaceutical Index.Andrew Weiss, an analyst at Bank Vontobel AG in Zurich, upgraded his peak sales forecast for Afinitor in breast cancer to $1.8 billion from $1.5 billion. Sales of the drug in all disease types may reach $3.5 billion, he wrote in a note today. Revenue from the medicine more than tripled last year to $243 million.Afinitor, which is already approved in the U.S. as a treatment for cancers of the kidney and pancreas, as well as non-cancerous brain tumors, blocks a protein called mTOR that some cancer cells require to grow and multiply. Novartis is also testing the drug in patients with other types of breast cancer, as well as lymphoma and stomach and liver cancer.Aromasin, also known as exemestane, stymies the production of the female hormone estrogen, which can spur the growth of breast tumors. Most women whose disease has spread aren’t helped by hormone therapy, and those who are usually become resistant to the treatment, Novartis said.The trial involved 724 women in 24 countries with an average age of 62 for whom hormone therapy was no longer controlling their cancer. Those who received Afinitor had a median delay of 6.9 months until their disease worsened, compared with 2.8 months among women who only received Aromasin, the study showed.A separate analysis showed the benefit may have been as much as 10.6 months, compared with 4.1 months. The most common severe side effects of Afinitor were mouth ulcers, anemia and shortness of breath.Novartis said in July that the trial had met its primary goal, and that Afinitor had “significantly” delayed disease progression, without providing details.More than 200,000 women worldwide have the form of breast cancer that Novartis is targeting with Afinitor, of which 85,000 live in wealthy places such as the U.S., Japan and in Europe, Hoppenot said.“We are very optimistic about this program,” he said. “It can become a very significant part of our portfolio over the next four, five years.”Afinitor should now be tested in women with early-stage breast cancer to see whether it can prevent tumors from recurring, said Richard Gelber, a professor in biostatistics at Harvard Medical School.“It works,” Gelber said in an interview in Stockholm. “Let’s move it forward and see if it can help other patients at an earlier phase.”Such studies are under discussion “but nothing is planned at this time,” Novartis said in an e-mail.