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As cancer treatment advances, patients and doctors push back against drugs’ harsh side effects

*March 2024*

For cancer patients, the harsh side effects of powerful drugs have long been the trade-off for living longer. Now, patients and doctors are questioning whether all that suffering is necessary.

They’ve ignited a movement to radically change how new cancer drugs are tested, with the U.S. Food and Drug Administration urging drugmakers to do a better job at finding the lowest effective dose, even if it takes more time.

Advances in treatment mean millions of people are surviving for years with incurable cancers. Jill Feldman, 54, of Deerfield, Illinois, has lived 15 years with lung cancer, thanks to that progress. Her parents both died of lung cancer months after their diagnoses.

But her cancer drug causes joint pain, fatigue and mouth sores that make eating and drinking painful.

“If you drink something that’s too hot, you really burn your mouth. That’s how my mouth feels 24/7,” Feldman said.

“No one should have to endure avoidable harmful effects of treatment,” she said.

Unlike in other diseases, cancer drug development has focused on finding what’s called the “maximum tolerated dose.”

To speed testing of chemotherapy drugs, researchers ramp up the dosage in a few people in early studies to determine the highest possible dose patients can tolerate. That “more is better” philosophy works for chemotherapy, but not necessarily for newer cancer drugs — like the one Feldman takes — which are more targeted and work differently.

Chemotherapy is like a battering ram where aggressive strikes are a good strategy. But newer cancer drugs are more like having a front door key. They target a mutation that drives cancer cell growth, for example, or rev up the body’s immune system to join the fight.

“You might only need a low dose to turn off that cancer driver,” said Dr. Lillian Siu, who leads cancer drug development at the Princess Margaret Cancer Center in Toronto. “If you can get the same bang for your buck, why go higher?”

Through a program called Project Optimus, the FDA is pushing drugmakers to include more patients in early dose-finding trials to get better data on when lower doses can work. A key motivation for the project was “the growing calls from patients and advocates that cancer drugs be more tolerable,” said FDA spokesperson Chanapa Tantibanchachai in an email. Read more.