The word of the week at the world's largest cancer meeting is "incremental." Some of the most notable data presented during the first two days of the annual American Society of Clinical Oncology (ASCO) meeting, June 1-5 in Chicago, was on new uses for existing drugs, rather than promising medicines still in the pipeline.
Whereas breakthrough advances in new, targeted therapies stole headlines at recent years' gatherings, the current highlights are studies showing improved uses for such established drugs as Genentech's (DNA) Avastin, ImClone Systems' (IMCL) Erbitux, and Bayer (BAY) and Onyx's (ONXX) Nexavar.
Nevertheless, medical experts at the meeting, attended by some 30,000 oncologists and researchers, say they are more encouraged than ever by the direction of research. "It's a very exciting time," says Dr. Robert Mayer, head of the gastrointestinal division at Dana-Farber Cancer Center in Boston. And the pace of new cancer drug development continues to accelerate. Titus Plattel, lead oncology consultant for market researcher IMS Health, says there are some 2,000 molecules under development for cancer treatment, and 50 new drugs for the disease should reach the market in the next three years. "Patients will be living longer as a result, and cancer will become more of a chronic disease, like AIDS, kept in check by these targeted drugs," he says. As a result, Plattel predicts that worldwide cancer drug sales will rise 17% to 20% a year through 2010, reaching $62 billion to $70 billion.
Focus on Targeting
All of this drug development doesn't necessarily mean major breakthroughs on an annual basis, however. "I think there's been a realization this year that there is not going to be new data every year in every cancer," says Dr. Roy Herbst, chief of thoracic surgery at M.D. Anderson Cancer Center in Houston. "There's a lot more focus on targeting the drugs we have, and figuring out which patients will gain the most benefit."
That was the message for Erbitux, one of the first of the new generation of cancer drugs to emerge in recent years that attacks only the tumor, doing minimal damage to healthy cells. Initially approved in 2002 for colon cancer, Erbitux has since been approved for several other cancers, including head and neck. European researchers reported June 2 that when Erbitux is combined with standard chemotherapy treatment in the early stages of the disease it can keep patients alive significantly longer. It is the first time a survival benefit has been demonstrated in this cancer when the drug was used as an initial treatment, rather than as a follow-on.
Dr. Jan Baptist Vermorken of the University of Antwerp in Belgium, lead author of the study, says the study should change the way patients with head and neck cancers are treated. The trial of 442 patients found that the median survival for those on chemo plus Erbitux was 10.1 months, compared with 7.4 months for those on chemo alone. The most common side effect for the Erbitux group was an acne-like rash. "Ultimately, the name of the game in cancer treatment is increased survival with a better quality of life, and that's what we're seeing here."
Studies of Avastin are also likely to expand the reach of the Genentech drug, the most successful of the new targeted treatments. Avastin, which blocks the growth of blood cells that provide nourishment to tumors, was approved in 2004 for colon cancer and has since been approved for several other cancers. At ASCO, studies were released showing that the drug can slow the growth of deadly kidney cancer by half when added to older therapies, and can slow the growth of advanced lung cancer when added to a chemotherapy regimen commonly used in Europe. The lung cancer study could be problematic for Genentech, however, because the dose of Avastin used in the study was half that of the dose commonly used in the U.S., but was just as effective.
Avastin may also soon face competition. A similar drug being jointly developed by Regeneron Pharmaceuticals (REGN) and Sanofi-Aventis (SNY), called VEGF Trap, proved effective in a study against chemo-resistant ovarian cancer. In preliminary results from a midstage trial, the drug shrank tumors in 8% of 153 patients, and stopped the tumors from growing in 71%. "The results are very promising," says Dr. William Tew of Memorial Sloan-Kettering Cancer Center in New York, the study's lead. The drug may be safer than Avastin in this patient group, as it caused a lower percentage of bowel perforation, a potentially deadly side effect.
Ovarian cancer is particularly tough to treat, and the study exemplified another trend in cancer research—an increasing number of drugs are being developed for the most difficult cancers. Pfizer (PFE), for example, showcased results from a trial of its experimental drug Axitinib, also similar to Avastin, against thyroid cancer. There have been no new drugs for this cancer in more than 30 years; it is usually treated with surgery and radioactive iodine. Axitinib shrank tumors in 22% of 60 patients, and stopped the cancer from growing in another 50%. "As recently as three years ago we had very little to offer these patients, and now we're seeing response rates at a level we've never experienced with chemotherapy," said Dr. Ezra Cohen of the University of Chicago, the lead investigator of the study.