Novartis Drug’s Radiation Blast Extends Prostate Cancer Survival

(Bloomberg) -- A Novartis AG drug that delivers a targeted blast of radiation directly to prostate cancer cells boosted survival by four months in a late-stage study in patients failed by other treatments.

Based on the results, Novartis said in a statement it plans to submit the drug to regulators for approval in the U.S. and European Union later this year. It also is starting up two big trials on the therapy’s potential effect in earlier stages of the disease.

If approved, the drug would bring a new type of precision radiation targeting to the most common kind of malignancy in men after skin cancer. The study results will be presented at the virtual American Society of Clinical Oncology, set to run June 4 through June 8.

“This is a different type of treatment, and that is a big value of this,” said Mary-Ellen Taplin, a genitourinary oncologist at Dana-Farber Cancer Institute, who enrolled some patients in the trial but wasn’t involved in analyzing the data. For patients who have failed other treatments, “it is a big deal,” she said

The research studied 831 advanced prostate cancer patients who were resistant to hormone therapy and who had failed or couldn’t tolerate at least one type of chemotherapy. Those who received the experimental Novartis drug, known as 177Lu-PSMA-617, plus standard therapy lived a median of 15.3 months. That compares to 11.3-month survival in a control group who received standard treatment alone.

The medicine also slowed the time it took the disease to progress, to a median of 8.7 months in people who got the drug versus 3.4 months for those with standard care. Another advantage: Novartis’s drug is given only once every six weeks compared with three-week intervals for typical prostate cancer chemotherapy regimens, Taplin said.

Still, Taplin said she was disappointed that the survival difference shown in the trial wasn’t bigger than four months, given the precise targeting enabled by the drug’s mechanism. “I had been hoping for more.”

Targeting Agent

The Novartis therapy consists of a targeting agent that binds to something called prostate-specific mebrane antigen, or PSMA, a protein present at high levels on the surfaces of most advanced prostate cancers, but not on most normal cells. The drug-like molecule is connected to lutetium-177, a radioactive metal isotope. The drug binds to prostate cancer cells and is sucked into them, and the radiation kills the cells and neighboring cells.

The delivery mechanism is a bit like DoorDash for cancer therapy, said Jeff Legos, Novartis’ head of oncology development, in a media briefing in advance of the meeting. Rather than carrying food, it delivers radiation “to a precise address based on the PSMA expression on the prostate cancer cells,” Legos said.

Novartis already sells a similar radiopharmaceutical drug for a rare neuroendocrine tumor. Now, Novartis’s newest effort is focused on prostate cancer,

Minerals in the Bone

Another radiopharmaceutical drug, Bayer AG’s Xofigo, is approved for advanced prostate cancer that has spread to the bone. It binds to minerals in the bone, where prostate cancer often spreads, and doesn’t specifically bring radiation to prostate cancer cells themselves.

But the PSMA delivery mechanism isn’t perfect, as some non-cancer cells have PSMA on them.

In Novartis’s final-stage study, severe or medically significant side effects occurred in 28.4% of people who got the radioactive drug compared to 3.9% of people who received standard treatment. Among other side effects, patients who received the treatment had higher rates of anemia, low platelet levels, low levels of certain white blood cells, and fatigue.

©2021 Bloomberg L.P.