Cancer Drugs: Herceptin News and MoreCatherine Arnst
Editor's Note: An earlier version of this story incorrectly stated the percentage of breast cancer cases classified as triple negative, as well as the number of women who responded to the Astra-Zeneca drug, Olaparib.
A breast cancer drug may work against stomach cancer. A drug commonly used for pancreatic and lung cancer may increase survival in victims of cervical cancer. An experimental drug shows great promise against an aggressive form of breast cancer, but it is also being tested against ovarian, brain, and lung cancer.
These are some of the drugs in the spotlight at the giant American Society of Clinical Oncology meeting in Orlando from May 29-June 2, one of the world's largest medical meetings. They represent the painstaking progress the drug industry has made over the last decade in developing cancer drugs that are site-agnostic—it doesn't matter where in the body a tumor starts as much as the structure of its molecular machinery. This is the slow emergence of personalized medicine, in which cancer patients receive a cocktail of drugs tailored to the exact genetic makeup of their cancer cells, as determined by a blood test. To patients it may not look like much progress at all, since most of these treatments add only a few months of survival on average. But scientists hope the steady accumulation of insights will eventually enable them to combine these targeted therapies in ways that may gain patients years of life rather than months.
"Personalized medicine is an easy concept but extremely difficult to get into place," says William M. Burns, CEO of Roche Pharmaceuticals, a unit of Roche Holding. "But I'm very excited about what is taking place here [at ASCO]. The science is evolving; we are at the beginning of the journey."
Oncology has been moving toward this vision of personalized treatment ever since Herceptin was introduced in 1998 by Genentech, now owned by Roche. Herceptin targets the 25% to 30% of breast cancers with a specific genetic mutation, called HER2, which fuels tumor growth. Because it knocks out only HER2 cells without harming healthy tissue, the drug has only mild side effects—the ideal targeted therapy. If a breast cancer patient tests positive for HER2, the patient gets it; if it's negative, she doesn't.
But a groundbreaking study presented at ASCO found that Herceptin can also improve the survival of patients with gastric cancer that test positive for HER2, the first time the drug has proven effective in another cancer. Stomach cancer is one of the world's most common cancers and will kill about 10,000 Americans this year. It is a particularly deadly malignancy—the median survival time after diagnosis is currently about 10 months.
Approximately 25% of stomach cancer patients test positive for HER2, however, prompting researchers to try Herceptin against the disease. There were 594 patients with HER2-positive stomach cancer enrolled in the Phase 3 study who received either a standard chemotherapy regimen plus Herceptin or chemotherapy alone. Patients in the Herceptin group had a median survival of 13.8 months, vs. 11.1 months for those getting standard treatment. Also, 47.3% of the Herceptin patients responded to the treatment, compared with 34.5% of those on chemo. Both results are considered highly significant in such sick patients. Roche says it will seek regulatory approval to use Herceptin against stomach cancer, and cancer specialists at the meeting speculated that the drug could become a new standard of care for this cancer.
Cervical cancer may also end up with a new standard of care after ASCO. Eli Lilly (LLY) reported that Gemzar, a chemotherapy most commonly used against pancreatic and lung cancers, was able to keep women with deadly cervical cancer alive longer when added to other forms of chemotherapy and radiation. It represents the first time the drug was tested against cervical cancer. The trial was also unusual in that it was almost entirely conducted in developing countries, where cervical cancer is a major killer. Dr. Alfonso Duenas-Gonzalez of the National Cancer Institute of Medicine reported that after three years of followup, 78% of the 259 women who received Gemzar were still alive, compared with 69% of 256 who received standard treatment alone.
Besides already approved drugs, ASCO attendees heard about new targeted treatments that might end up working against any number of cancers as long as they contain the target. A number of companies are developing drugs, for example, that take aim at PARP, an enzyme cancer cells employ to repair the damage inflicted by chemotherapy drugs. Like Herceptin and HER2, anti-PARP drugs will work only in those patients whose tumors have excess amounts of the enzyme, but that could be a number of cancers, including lung and ovarian.
The most advanced anti-PARP drug is BSI-201, developed by BiPar Sciences, which Sanofi-Aventis (SNY) acquired in March. The drug is being tested on women with a rare but deadly form of breast cancer called triple negative, about 15% of all cases. In the trial of 116 women, approximately 62% of patients who received the drug in combination with chemotherapy had their tumors shrink, compared with 21% of those who received chemotherapy only. A similar PARP drug, Olaparib, made by AstraZeneca (AZN), was tested as a single agent in a trial of 54 women with advanced breast cancer, and shrank tumors in one-third of those given the drug.
Cancer specialists cautioned that oncology still has a long way to go before personalized medicine becomes the norm but said the accumulation of small steps like the ones presented at ASCO this year are an encouraging sign that the field is moving in the right direction. "Right now we're using personalized medicines in a nonpersonalized way," says Dr. Roy Herbst, a lung cancer specialist at M.D. Anderson Cancer Center in Houston. "But we are getting there."