FDA Approves Drug to Help Curb a Tough-to-Treat Prostate Cancer

From Drugs.com - February 14, 2018

FDA Approves Erleada to Help Curb a Tough-to-Treat Prostate Cancer

WEDNESDAY, Feb. 14, 2018 -- A new drug that can stall the progression of a particularly hard-to-treat form of prostate cancer has been approved for use by U.S. health officials.

In a recent study, the drug called Erleada (apalutamide) has shown breakthrough effectiveness in keeping prostate cancer from spreading for two years in men whose disease had not yet traveled to other parts of their body.

After the drug was granted Priority Review by the U.S. Food and Drug Administration, the agency announced Wednesday that it had approved Erleada "for the treatment of patients with prostate cancer that has not spread (non-metastatic), but that continues to grow despite treatment with hormone therapy."

A second, already approved drug, Xtandi (enzalutamide), has also shown similar effectiveness against these types of prostate cancer cases.

Dr. Matthew Smith was primary researcher of the Erleada trial that helped lead to the new approval. His team published its results Feb. 8 in the New England Journal of Medicine.

Smith explained that men newly diagnosed with prostate cancer that has not spread are first treated with androgen-deprivation therapy -- a medication that robs the tumor of the testosterone that helps fuel its growth.

This strategy "always works, and [then] it almost always stops working," said Smith, who directs the genitourinary malignancies program at Massachusetts General Hospital in Boston.

"And when it stops working, that's what we call castration-resistant prostate cancer," he explained.

Until now, there have been no approved treatments for prostate cancer at that stage, Smith said. The men are simply put under observation until their cancer migrates, at which point treatment resumes.

Tens of thousands of men in the United States are estimated to be in this situation and they have a very poor prognosis, particularly if their levels of prostate-specific antigen (PSA) are rapidly rising, Smith said. PSA is a protein produced by the prostate gland; a sudden elevation of PSA levels has been linked to increased prostate cancer risk.

"There's an unmet need there," Smith said. "Their expected survival is similar to that of men with newly diagnosed prostate cancer that has already spread to bone."

Both Erleada and Xtandi battle prostate cancer by binding to the androgen receptor on tumor cells, blocking its activation by testosterone and other male hormones, explained Dr. Oliver Sartor, medical director of the Tulane Cancer Center in New Orleans. He co-wrote a commentary accompanying the apalutamide trial.

"Both the drugs are incredibly similar to one another," Sartor said. "If you look at the chemical structure, they are extremely close to one another. Mechanistically, they operate the same way."

In the Erleada trial, Smith's group tested the pill against a placebo.

The result: Erleada extended progression-free survival by about two years over a placebo, researchers found -- 40.5 months versus 16.2 months. That means patients continued to live their lives without the disease progressing.


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