For years, doctors told multiple myeloma patients to stay on a drug called lenalidomide forever — or at least until the cancer came back. Now, a major study suggests they might be able to stop after just two years without any difference in how long they live.
The clinical trial, called ENDURANCE, followed 516 patients with a type of blood cancer called multiple myeloma for a median of seven years. Half the patients kept taking lenalidomide until their cancer got worse. The other half stopped after two years. By the end of the study, survival rates were almost identical: 69 percent of the continuous-treatment group was still alive, compared to 68.6 percent of those who stopped early. That's a difference of less than half a percentage point — essentially the same.
"The results of this trial are paradigm-shifting," said Dr. Shaji K. Kumar, a blood cancer specialist at the Mayo Clinic in Rochester, Minnesota, who led the study. "Fixed-duration treatment can significantly reduce health care costs, especially given the improving survival of patients with myeloma."
The study, published in the New England Journal of Medicine, also found that patients who stayed on the drug longer faced more side effects. About 23.5 percent of people on continuous treatment experienced serious non-blood-related side effects, compared to just 16.9 percent of those who stopped after two years. There was also a slightly higher rate of new cancers in the continuous-treatment group: 11.2 percent developed a second cancer within five years, versus 8.3 percent in the limited-duration group.
Multiple myeloma is a cancer that forms in white blood cells called plasma cells. It weakens the immune system and can cause bone pain, kidney problems, and anemia. Maintenance therapy — lower-dose treatment given after initial chemotherapy — helps keep the cancer under control, but side effects like fatigue, nausea, and increased infection risk can make long-term use difficult.
Yelak Biru, a multiple myeloma survivor who helped design the trial as a patient advocate, said the question of how long to stay on treatment is one of the most common questions patients ask. "For patients, maintenance therapy is not just another medication. It becomes part of everyday life," he said.
Dr. S. Vincent Rajkumar, another hematologist at Mayo Clinic and senior author of the study, estimated that changing this standard practice could save Medicare — the U.S. health insurance program for people 65 and older — more than $1 billion. The trial was conducted by the ECOG-ACRIN Cancer Research Group, a network that runs clinical trials across the United States.
The findings apply to patients who did not receive a stem cell transplant, which represents the majority of myeloma patients. Researchers say the evidence could reshape how doctors counsel patients about the benefits and burdens of staying on lenalidomide for years.