CHICAGO -- Drugs are scoring big wins against common cancers, setting new standards for how to treat many prostate, breast and lung tumours. There's even a "uni-drug" that may fight many forms of the disease.
What's striking: The drugs are beneficial in some cases for more than a year, much longer than the few months many new drugs provide. Here are highlights from the world's largest cancer meeting, the American Society of Clinical Oncology conference in Chicago.
PROSTATE CANCER
Janssen Biotech's Zytiga improved survival and delayed cancer growth for 18 months when added to standard care in a study of 1,200 men with advanced prostate cancer. The drug is approved to treat tumours that are resistant to hormone therapy; this study tested it as initial treatment.
The study was stopped early because men on Zytiga were living longer -- 66 per cent were alive after three years versus 49 per cent of a comparison group not given the drug. Zytiga also delayed the time until cancer worsened -- 33 months versus 15 months for the others.
In a second study of 1,900 men newly diagnosed with advanced prostate cancer, adding Zytiga to usual treatment also improved survival: 83 per cent were alive at three years versus 76 per cent of men not given the drug. Zytiga also cut the chance of relapse and serious bone problems.
Zytiga caused more side effects, including high blood pressure, but the benefits outweigh them, doctors said.
The results will change practice "pretty much overnight," said Dr. Richard Schilsky, chief medical officer for the group hosting the conference. Most men with prostate cancer that has spread will be eligible for Zytiga -- about 25,000 each year in U.S. and more in other countries where more cases are found at a late stage, he said. Zytiga costs about $10,000 a month in the U.S.
LUNG CANCER
Roche's Alecensa stopped cancer growth for 15 months longer than Pfizer's Xalkori did in a study of 303 people with advanced lung cancer and a mutation in a gene called ALK. About 5 per cent of lung cancer patients -- 12,500 in the U.S. each year -- have an ALK mutation, especially younger people and nonsmokers who get the disease.
Alecensa kept cancer from worsening for 26 months versus 11 months for Xalkori. It also penetrates the brain better: only 9 per cent of those on it had their lung cancer spread to the brain during the first year of treatment versus 41 per cent of those on Xalkori. Serious side effects and deaths were less common with Alecensa.
The U.S. Food and Drug Administration approved it in December 2015 for ALK-related lung cancers that worsened despite trying Xalkori. The new study tested it as initial treatment and is aimed at getting full approval for that.
Xalkori is around $10,000 a month and Alecensa, about $12,500.
BREAST CANCER
For the first time, a new type of drug called a PARP inhibitor showed promise in a major study of women with inherited BRCA gene mutations that raise their risk of developing breast cancer. PARP inhibitors keep cancer cells from fixing problems in their DNA, and some are approved now for some ovarian cancers.
The study tested AstraZeneca's Lynparza in 302 women with cancers that had spread beyond the breast and were not the type that respond to the drug Herceptin. Half were "triple negative," meaning they are not helped by Herceptin or drugs that block the two main hormones that fuel breast cancer's growth. All had previously tried chemotherapy and some had tried hormone blockers.
Lynparza modestly delayed the time until cancer worsened -- 7 months versus 4 months for women given one of three commonly used chemotherapies. Lynparza's main side effects were nausea, fatigue and blood count problems, but serious problems were less common than with chemo. It's too soon to know whether Lynparza improves survival. It costs about $13,000 a month.
A UNI-DRUG?
Loxo Oncology Inc.'s larotrectinib is aimed at many types of cancer with a certain gene abnormality, and in children as well as adults -- a first on both counts. The gene problem occurs in less than 1 per cent of cancers, so a big question is how these rare gene problems would be found unless widespread tumour-gene testing becomes more common than it is now.
In a study of 50 patients with 17 different kinds of cancer, 76 per cent -- an unusually high number -- responded to treatment and their disease has not worsened. Side effects include fatigue and mild dizziness.
The company will seek FDA approval based on these results. Last month, the FDA said Merck's immune therapy drug Ketruda could be used for any pediatric or adult cancer with certain gene features, but larotrectinib would be the first drug developed from scratch with this approach.
