A new generation of cancer treatments is emerging from the world's drug laboratories that may deliver on the oncology community's grand vision: keeping the disease in check for months or even years with a drug that targets tumor cells with minimal side effects. If that one drug stops working, the patient can then be switched to another. The first of these so-called targeted treatments have been trickling onto the market for the past several years, and this year, the world's premier cancer conference is showcasing some promising follow-ons (see BW Online, 06/02/06, "Big Pharma in the Cancer Spotlight").
Seven years ago, Genentech (DNA) galvanized the American Society of Clinical Oncology (ASCO) meeting with studies showing that Herceptin, one of the first targeted drugs, has remarkable efficacy in women with a certain type of breast cancer. This year, at the June 2-6 meeting in Atlanta, GlaxoSmithkline (GSK) took the spotlight with Tykerb, for women who have grown resistant to Herceptin. Five years ago, Gleevec from Novartis (NVS) was the star of ASCO for its ability to extend the lives of patients with deadly forms of leukemia and stomach cancers.
This year, BristolMyers Squibb (BMY) reported that its new drug, Dasatinib, can keep leukemia patients alive once they have failed Gleevec. And last year, Pfizer's (PFE) Sutent won accolades for slowing the disease in patients with kidney cancer, one of the hardest malignancies to treat. Sutent was only approved in January, and yet this year Wyeth (WYE) presented data demonstrating that its experimental kidney drug, temsirolimus, extended the lives of patients -- the gold standard of efficacy for cancer treatment.
CANCER COCKTAIL? None of these drugs, or the hundreds of others discussed at ASCO, claim to be a cure. But leading specialists say the cancer treatment regimen is getting closer to the AIDS model, where a patient can be kept alive for years with a combination of drugs. In fact, researchers presented a study showing that Gleevec has kept alive 89% of patients with chronic myeloid leukemia for five years, compared with 45% to 65% on other, harsher treatments. "This is a very exciting, very promising time in oncology," says Dr. Roy S. Herbst, chief of thoracic medical oncology at the University of Texas M.D. Anderson Cancer Center in Houston. "We really can give patients reason to hope."
Kidney cancer patients, in particular, have reason to be optimistic. The disease killed some 11,000 Americans last year, and the median survival after diagnosis is four months. If a tumor could not be removed surgically, the only treatment was particularly toxic forms of chemotherapy developed two decades ago. Early this year, however, the Food & Drug Administration approved both Sutent and Nexacar, jointly developed by Onyx Pharmaceuticals (ONXX) and Bayer (BAY), and several more targeted therapies are in the pipeline.
Sutent was approved for patients who had failed chemotherapy, but a study presented at ASCO found that in patients who went on Sutent first, tumors grew more slowly when compared to those who had the first-line treatment, interferon. "As a result of this trial, we believe (Sutent) will become the new standard of care" for advanced kidney cancer, said Dr. Robert J. Motzer of Memorial Sloan-Kettering Cancer Center in New York, lead investigator of the study (see BW Online, 11/21/05, "The Spirit of a Startup Lives On").
DRUG FACE-OFF. The Wyeth drug, which is not yet approved, appeared to perform even better than Sutent by extending survival in very sick patients to 10.9 months, compared with 7.3 months for those who received standard treatment. However, the two patient populations were very different -- those in the Wyeth trial were much sicker. And the Wyeth drug takes aim at a different tumor target than Sutent, making it even more difficult to make direct comparisons.
That's not the case with Glaxo's Tykerb and Genentech's Herceptin. Both drugs work very similarly, and though Glaxo says the drug is meant for those patients for whom Herceptin no longer works, there are widespread expectations that if Tykerb wins FDA approval it will compete directly against Herceptin. "It's a very promising drug," says Dr. Eric Winer, breast cancer expert at Dana Farber Cancer Center in Boston. "I think it will be approved and it will be tested as a first-line therapy." Glaxo says it plans to file for approval by yearend.
In the same way, BristolMyer's Dasatinib could also end up competing against Gleevec, the drug it is meant to follow in a course of treatment, and that face-off may come sooner rather than later. On June 2, an FDA advisory panel voted to recommend approval of the drug; the FDA is expected to issue its decision by June 28. The competition might make life more difficult for the drug companies, but it's good news for cancer patients.