Immunotherapy side effects may be more common than thought

(HealthDay)—Adverse events for immune checkpoint inhibitors used to treat non-small cell lung cancer (NSCLC) may be more common in real-world settings than reported in the clinical trials that led to U.S. Food and Drug Administration approvals, according to a study presented at the annual Palliative and Supportive Care in Oncology Symposium, held from Nov. 16 to 17 in San Diego.

Elizabeth Jane Cathcart-Rake, M.D., from the Mayo Clinic in Rochester, Minnesota, and colleagues used administrative claims data from a large U.S. commercial insurance database (OptumLabs Data Warehouse) to retrospectively identify patients with NSCLC who received programmed cell death 1 or programmed death ligand 1 inhibitors from 2015 through 2017. The frequencies of immune-related adverse events were identified through ICD-9 or ICD-10 codes.

The researchers found that the most common immune-related adverse outcome was hypothyroidism, which occurred in 9.2 percent of patients. Anemia occurred in 5.7 percent of patients and acute kidney injury occurred in 2.8 percent of patients, while gastrointestinal and cardiac events were relatively rare. The KEYNOTE-24 trial, which compared pembrolizumab to chemotherapy revealed that 0.6 percent of patients had hypophysitis, a rare condition involving acute or chronic inflammation of the pituitary gland, while this analysis showed that 2.4 percent of patients experienced hypophysitis.

"Immunotherapy continues to be well tolerated, and severe side effects are less frequent than those seen with conventional chemotherapy. Still, immunotherapy can, in rare occasions, cause other serious medical problems," Cathcart-Rake said in a statement. "It's important to understand the full extent of cancer treatments' side effects, and patients and providers should be aware that it can take a while to fully assess them for newer therapies."

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