Doctors are reporting improved survival in men with advanced prostate cancer from an experimental drug that delivers radiation directly to tumor cells.
Few such drugs are approved now, but the approach may become a new way to treat patients with other hard-to-reach or inoperable cancers.
The study tested an emerging class of medicine called radiopharmaceuticals, drugs that deliver radiation directly to cancer cells. The drug in this case is a molecule that contains two parts: a tracker and a cancer-killing payload.
Trillions of these molecules hunt down cancer cells, latching onto protein receptors on the cell membrane. The payload emits radiation, which hits the tumor cells within its range.
“You can treat tumors that you cannot see. Anywhere the drug can go, the drug can reach tumor cells,” said Dr. Frank Lin, who had no role in the study but heads a division at the National Cancer Institute that helps develop such medicine.
Results were released Thursday by the American Society of Clinical Oncology ahead of its annual meeting this weekend. The study was funded by Novartis, the drug’s maker, which plans to seek approvals in the United States and Europe later this year.
When cancer is confined to the prostate, radiation can be beamed onto the body or implanted in pellets.
But those methods don’t work well in more advanced prostate cancer. About 43,000 men in the United States each year are diagnosed with prostate cancer that has spread and is no longer responding to hormone-blocking treatment.
The study tested a new way to get radiation treatment to such patients.
It involved 831 men with advanced prostate cancer. Two-thirds were given the radiation drug and the rest served as a comparison group. Patients got the drug through an IV every six weeks, up to six times.
After about two years, those who received the drug did better, on average. The cancer was kept at bay for nearly nine months compared to about three months for the others. Survival was better too — about 15 months versus 11 months.
The gain may not seem like much, but “these patients don’t have many options,” said ASCO president Dr. Lori Pierce, a cancer radiation specialist at the University of Michigan.
Radioactivity can reduce blood cell production, which can lead to anemia and clotting problems for patients. In the study, 53% of the patients had serious side effects compared to 38% of patients in the comparison group. Both groups were allowed to get other treatments.
The results pave the way for government approval and will boost interest in radiation drugs, Lin said.
Others already in use include Novartis’ Lutathera for a rare type of cancer of the stomach and gut.
And Bayer’s Xofigo is approved for men whose prostate cancer has spread to the bone but not elsewhere. Xofigo targets areas where the body is trying to repair bone loss from tumor damage, but it isn’t directly aimed at prostate cancer cells wherever they may be in the body.
Since the experimental drug targets tumor cells, “that would be a first for prostate cancer,” Lin said.
In the coming decade, such drugs “will be a major thrust of cancer research,” said Dr. Charles Kunos, who worked on standards for radiopharmaceutical research at the National Cancer Institute before leaving to join University of Kentucky’s Markey Cancer Center. “It will be the next big wave of therapeutic development.”
“There’s great potential” with drugs being tested for melanoma and breast, pancreatic and other cancers, said Dr. Mary-Ellen Taplin of Dana-Farber Cancer Institute in Boston, who enrolled patients in the study and reviewed the data.
As for prostate cancer, “it opens up a range of future strategies,” including at earlier stages of disease and alongside other treatments, said study leader Dr. Michael Morris of Memorial Sloan Kettering Cancer Center in New York.
___
The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.
Pill shows benefit in certain hard-to-treat breast cancers
A pill has been shown to help keep certain early-stage, hard-to-treat breast cancers at bay after initial treatment in findings being reported early because they are so promising.
Study results were released Thursday by the American Society of Clinical Oncology ahead of its annual meeting and published in the New England Journal of Medicine.
The pill, called Lynparza, was found to help breast cancer patients with harmful mutations live longer without disease after their cancers had been treated with standard surgery and chemotherapy.
It was studied in patients with mutations in genes known as BRCA1 and BRCA2 that can predispose people to breast cancer if they don’t work properly, but who did not have a gene flaw that can be targeted by the drug Herceptin.
Most patients in the study also had tumors that were not fueled by the hormones estrogen or progesterone. Cancers not fueled by these two hormones or by the gene Herceptin targets are called “triple negative.” They are especially hard to treat.
The new study tested Lynparza in 1,836 women and men with early-stage disease who were given the drug or placebo pills for one year after surgery and chemotherapy. About 82% of patients in the study had triple-negative breast cancer.
Independent monitors advised releasing the results after seeing clear benefit from Lynparza. After three years, 86% of patients on it were alive without their cancer recurring compared to 77% in the placebo group.
The results suggest more patients should get their tumors tested for BRCA mutations to help guide treatment decisions, said ASCO president Dr. Lori Pierce, a cancer radiation specialist at the University of Michigan.
Serious side effects were not more common with the drug. Other side effects included anemia, fatigue and blood cell count abnormalities.
Lynparza, which is marketed by AstraZeneca and Merck, is already sold in the United States and elsewhere for treating breast cancers that have widely spread and for treating certain cancers of the ovaries, prostate and pancreas. It costs roughly $14,000 per month, though what patients pay out of pocket varies depending on income, insurance and other factors.
The study was supported by AstraZeneca and the National Cancer Institute.
___
The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.