The results of Denise Nichols's genetic test were both a blessing and a curse. After doctors diagnosed her with advanced ovarian cancer in 2009, Nichols, 54, a nurse from Hamden, Conn., was treated with surgery and chemotherapy and tested for genetic glitches that predispose women to breast and ovarian cancer. Her test confirmed a harmful hiccup in the BRCA2 gene that made her 10 to 27 times more likely to develop ovarian cancer than the average woman. But the finding had a bright side: It meant that Nichols could take a promising new drug, one thought to work only in women with defective BRCA genes.
The drug blocks the action of a protein known as PARP that helps tumors in women like Nichols survive by repairing breaks in the DNA of their cells. Last summer, doctors detected rising levels of a cancer-related protein in Nichols's blood—a warning that her cancer might be coming back. Since March, Nichols has been taking the new drug, and her blood protein levels have dropped to near normal. "I want to be the one that this drug works on," she says. "And I don't ever want to have to go back on chemotherapy again."
Nichols's battle is part of a revolution in cancer treatment that has swept the field in the past two years. Rather than treat all breast or kidney or lung tumors in the same way, doctors are now peering deep into the genetic code of a patient's cancer, personalizing a treatment path according to its specific mutations, and, if not yet providing a cure, often extending lives by many months—and offering hope. Based on a wave of new research, such as a study released in April revealing that the tumors of nearly 2,000 breast cancer patients could essentially be classified into 10 different types of the disease, a growing number of cancer centers now routinely survey patients' cancers for mutations. "There's a small list of genes which we should be fully aware of when we treat patients with target therapeutics," says Frank McCormick, director of the University of California–San Francisco Helen Diller Family Comprehensive Cancer Center. "At some point, the technology of deep sequencing of patients' genomes will become the standard of care."
A rapid pace. The personalized medicine movement is gaining steam because dozens of these "targeted therapies" are now available. Since Herceptin was approved 14 years ago to treat breast cancer in patients whose tumors overproduce a protein called HER2, a mere trickle of tailored therapies followed over the next decade. Then, the pace picked up. Last year, the Food and Drug Administration approved two breakthrough drugs: crizotinib for lung cancer and vemurafenib for melanoma. In lung cancer patients whose tumors express a version of the anaplastic lymphoma kinase (ALK) gene that is incorrectly fused to a separate gene, crizotinib blocks a tumor-promoting protein made by the fused gene. Vemurafenib inhibits a protein made by a gene called BRAF in the roughly half of melanoma patients who have an overactive form of BRAF. In preliminary results from a trial that was promising enough that it was stopped early, nearly 50 percent of the patients taking vemurafenib saw their tumors recede, compared to fewer than 6 percent of the patients being treated with standard chemotherapy. Last year will be remembered as the year that personalized medicine really began to take off as a weapon against cancer, says Stafford O'Kelly, president of Des Plaines, Ill.-based Abbott Molecular, which developed a test for the ALK mutation.
Most of the new drugs block the action of genes called oncogenes that, when mutated, send unchecked growth signals to cancer cells. A number of cancers share a faulty version of an oncogene called epidermal growth factor receptor (EGFR), for example; medications now exist to foil its action in patients with colorectal cancer, head and neck cancers, lung cancer, and pancreatic cancer. Imatinib, known by the brand name Gleevec, has proved to be a true lifesaver in the treatment of chronic myelogenous leukemia caused by a glitch that turns on an oncogene that's part of a class called receptor tyrosine kinases. It is now also approved to treat more than seven other cancers caused by receptor tyrosine kinases, including gastrointestinal tumors and some skin tumors.