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• Posted April 21, 2025

Lung Cancer Remains At Bay Long After Immune Therapy Is Dropped

MONDAY, April 21, 2025 (HealthDay News) — Immunotherapy might help keep lung cancer at bay for months or even years after the treatment has been abandoned due to side effects, a new study says.

Immune checkpoint inhibitors essentially take the brakes off the immune system, giving it free reign to hunt down and kill cancer cells.

Unfortunately, this hyperstimulation of the immune system can also cause adverse effects like pneumonia, inflammation of the colon or liver damage — at which point people are taken off the drugs.

But new results indicate the immune system keeps attacking cancer even if immune checkpoint inhibitors have been dropped from a person’s treatment regimen.

On average, it took nearly 13 months for patients’ lung cancer to start spreading again after they dropped the immunotherapy, researchers reported April 18 in the journal Clinical Cancer Research.

These patients also survived 3-1/2 years on average after they stopped receiving immune checkpoint inhibitors, researchers reported.

The longer a person took the drugs, the better their outcome after stopping the meds, the study found.

“These outcomes suggest that patients can experience prolonged disease control and survival after stopping treatment due to toxicity or if side effects are impacting their quality of life,” lead investigator Dr. Frederica Pecci, a research fellow with Dana-Farber Cancer Institute in Boston, said in a news release.

Between 3% and 12% of patients treated with a single immune checkpoint inhibitor need to discontinue treatment due to serious side effects, researchers said in background notes. That number jumps to as high as 25% if people are treated with two of the drugs.

“When immunotherapy activates the immune system, the goal is to selectively target cancer cells. But this activation can also cause inflammation in other organs,” senior researcher Dr. Mark Awad, chief of thoracic oncology at Memorial Sloan Kettering Cancer Center in New York City, said in a news release.

“Whenever we see these side effects, we question whether we should keep giving immunotherapy or if we need to stop treatment temporarily or permanently,” he said.

To see whether immunotherapy keeps working even after it’s stopped, researchers evaluated data from nearly 2,800 patients with advanced non-small cell lung cancer who were prescribed immune checkpoint inhibitors.

Of those patients, about 10% had to stop the immunotherapy due to serious side effects.

Results showed that the longer a person could stand to be on immune checkpoint inhibitors, the better their outcomes were on average once they stopped taking the meds:

• Those who quit after less than three months saw their cancer stalled for six months and survived for nearly 22 months.

• Those who got three to six months of treatment had their cancer stalled for 14 months and survived for nearly 43 months, or 3-1/2 years.

• Those who got more than six months of treatment had their cancer stalled for 26 months and survived for 87 months – more than 7 years.

The team also “identified clinical and pathological features that can help physicians to better understand which patients can benefit longer without any additional treatment after discontinuing for toxicity,” Pecci said.

Sometimes patients can be kept on immune checkpoint inhibitors for a little longer if their symptoms can be managed using steroids or other anti-inflammatory drugs, researchers said.

In fact, the study showed that the use of steroids or other immune-suppressing drugs during treatment did not affect a patients’ length of survival after immunotherapy was dropped.

“Our study can serve as a valuable resource to support clinicians in the complex considerations of treatment discontinuation,” Pecci added.

More information

The National Cancer Institute has more on immune checkpoint inhibitors.

SOURCE: American Association for Cancer Research, news release, April 18, 2025