Checkpoint Inhibitors Seem Safe in Autoimmune Disease

WASHINGTON — Immune checkpoint inhibitor (ICI) therapy does not increase mortality in people with preexisting autoimmune diseases, new research has found. 

Results from a large database analysis of patients with and without autoimmune diseases suggest it is safe to treat them with ICI if they develop a cancer for which it is indicated, Greg Challener, MD, a postdoctoral fellow at the Rheumatology and Allergy Clinical Epidemiology Research Center, Massachusetts General Hospital, Boston, said at the American College of Rheumatology 2024 Annual Meeting.

“One message is that, when rheumatologists are asked by oncologists about patients with rheumatoid arthritis or vasculitis or other autoimmune diseases and whether it’s safe to treat them with immune checkpoint inhibitors, this result provides some evidence that it probably is safe…. Checkpoint inhibitors are really incredible drugs, and they’ve improved mortality for a lot of cancers, particularly melanoma, and so I think there should be a pretty high threshold for us to say a patient shouldn’t receive them because of an autoimmune condition,” he told Medscape Medical News.

Another implication, Challener said, is that people with autoimmune diseases shouldn’t routinely be excluded from clinical trials of ICIs. Currently they are excluded because of concerns about exacerbation of underlying autoimmunity, possible interference between the ICI and the immunosuppressive drugs used to treat the autoimmune condition, and a theoretical risk for serious adverse events. 

“Clinical trials are continuing to exclude these patients, and they paint with a very broad brush anyone with underlying autoimmunity…. I’m hoping that that changes. I don’t think there’s a great evidence base to support that practice, and it’s unfortunate that patients with underlying autoimmune diseases are excluded from important studies,” Challener said.

Asked to comment, session moderator Matlock Jeffries, MD, director of the Arthritis Research Unit at the Oklahoma Medical Research Foundation, Oklahoma City, told Medscape Medical News that he agrees the data are generally reassuring. “If one of our patients gets cancer and their oncologist wants to use a checkpoint inhibitor, we’d obviously still monitor them for complications, but we wouldn’t automatically assume the combination of a checkpoint inhibitor and autoimmune disease would increase their mortality.” 

No Difference in Mortality for Those With and Without Autoimmune Disease

Challener and colleagues used administrative health data from the TriNetX Diamond network of 92 US healthcare sites with 212 million patients. All patients included in the study were receiving anti-programmed death protein 1/programmed death ligand 1 to treat malignancies involving the skin, lung/bronchus, digestive organs, or urinary tract. The study population also had at least one rheumatologic, gastrointestinal, neurologic, dermatologic, or endocrine autoimmune disease.

Propensity score matching between those with and without autoimmune disease was performed for about 100 covariates. Prior to the matching, the autoimmune disease group had significantly higher rates of cardiovascular and other comorbidities. The matching yielded 23,714 individuals with autoimmune disease and the same number without who had similar demographics and comorbidity rates, as well as malignancy type, alcohol/tobacco use, and medication use. 

At a median follow-up of 250 days, the risk for mortality prior to propensity matching was 40.0% in the autoimmune disease group and 38.1% for those without, a significant difference with hazard ratio 1.07 (95% CI, 1.05-1.10). But after the matching, the difference was no longer significant: 39.8% vs 40.2%, respectively (0.97, 0.94-1.00). 

The Kaplan-Meier curves for survival probability for those with or without autoimmune disease were nearly superimposed, showing no difference up to 1600 days. An analysis of just the patients with rheumatic diseases yielded similar results, Challener said. 

Some Caveats About the Data

Jeffries, who is also an associate professor of medicine at the University of Oklahoma Health Sciences Center, Oklahoma City, and the Oklahoma VA, said he would like to see additional data on outcomes, both for the autoimmune conditions and the cancers. Challener said there are plans to look at other hard endpoints such as myocardial infarction and end-stage renal disease, but that the database is limited. 

Both Challener and Jeffries also cautioned that the reassurance may not apply to patients with active disease. 

“One thing this research doesn’t address is whether active autoimmune disease might have a different outcome compared to more kind of quiet disease…. If you have a patient who has extremely active rheumatoid arthritis or extremely active giant cell arthritis, for instance, I think that could be more challenging. I would be frightened to put a patient with really active GCA on pembrolizumab or say that it’s safe without their disease being controlled. But for someone who has well-controlled disease or minimally active disease, this is very reassuring,” Challener told Medscape Medical News.

“I think this may also be important in that it’s a good argument to tell the drug companies to include autoimmune patients in these trials so we can get better data,” Jeffries commented.

Challener and Jeffries had no relevant disclosures. 

Miriam E. Tucker is a freelance journalist based in the Washington, DC, area. She is a regular contributor to Medscape Medical News, with other work appearing in the Washington Post, NPR’s Shots blog, and Diatribe. She is on X @MiriamETucker.