Checkpoint Inhibitor Safety in Preexisting Autoimmune Diseases2021-02-17
Patients with advanced melanoma and preexisting autoimmune diseases (AIDs) who were treated with immune checkpoint inhibitors (ICIs) responded well and did not suffer more grade 3 or higher immune-related adverse events than patients without an AID, a new study finds, although some concerns were raised regarding patients with inflammatory bowel disease (IBD).
“To our knowledge, this is the first study to bridge this knowledge gap by presenting ‘real-world’ data on the safety and efficacy of ICI on a national scale,” wrote Monique K. van der Kooij, MD, of Leiden (the Netherlands) University Medical Center and coauthors. The study was published online in Annals of Internal Medicine.
To investigate ICI use and response among this specific subset of melanoma patients, the researchers launched a nationwide cohort study set in the Netherlands. Data were gathered via the Dutch Melanoma Treatment Registry (DMTR), in which 4,367 patients with advanced melanoma were enrolled between July 2013 and July 2018.
Within that cohort, 415 (9.5%) had preexisting AIDs. Nearly 55% had rheumatologic AIDs (n = 227) – which included RA, systemic lupus erythematosus, scleroderma, sarcoidosis, and vasculitis – with the next most frequent being endocrine AID (n = 143) and IBD (n = 55). Patients with AID were older than patients without (67 vs. 63 years) and were more likely to be female (53% vs. 41%).
The ICIs used in the study included anti-CTLA4 (ipilimumab), anti–programmed death 1 (PD-1) (nivolumab or pembrolizumab), or a combination of nivolumab and ipilimumab. Of the patients with AID, 55% (n = 228) were treated with ICI, compared with 58% of patients without AID. A total of 87 AID patients were treated with anti-CTLA4, 187 received anti-PD-1, and 34 received the combination. The combination was not readily available in the Netherlands until 2017, the authors stated, acknowledging that it may be wise to revisit its effects in the coming years.
Incidence of Immune-Related Adverse Events
The incidence of immune-related adverse events (irAEs) grade 3 and above for patients with and without AID who were given anti-CTLA4 was 30%. The incidence rate of irAEs was also similar for patients with (17%; 95% confidence interval, 12%-23%) and without (13%; 95% CI, 12%-15%) AID on anti-PD-1. Patients with AIDs who took anti-PD-1 therapy discontinued it more often because of toxicity than did the patients without AIDs.
The combination group had irAE incidence rates of 44% (95% CI, 27%-62%) for patients with AID, compared with 48% (95% CI, 43%-53%) for patients without AIDs. Overall, no patients with AIDs on ICIs died of toxicity, compared with three deaths among patients without AID on anti-CTLA4, five deaths among patients on anti-PD-1, and one patient on the combination.
Patients with IBD had a notably higher risk of anti-PD-1–induced colitis (19%; 95% CI, 7%-37%), compared with patients with other AIDs (3%; 95% CI, 0%-6%) and patients without AIDs (2%; 95% CI, 2%-3%). IBD patients were also more likely than all other groups on ICIs to stop treatment because of toxicity, leading the researchers to note that “close monitoring in patients with IBD is advised.”
Overall survival after diagnosis was similar in patients with AIDs (median, 13 months; 95% CI, 10-16 months) and without (median, 14 months; 95% CI, 13-15 months), as was the objective response rate to anti-CTLA4 treatment (10% vs. 16%), anti-PD-1 treatment (40% vs. 44%), and combination therapy (39% vs. 43%).
Study Largely Bypasses the Effects of Checkpoint Inhibitors on RA Patients
“For detail, you can’t look to this study,” Anne R. Bass, MD, of the division of rheumatology at the Hospital for Special Surgery in New York, said in an interview. “But for a big-picture look at ‘how safe are checkpoint inhibitors,’ I think it’s an important one.”
Dr Anne Bass
Bass noted that the investigators lumped certain elements together and bypassed others, including their focus on grade 3 or higher adverse events. That was a decision the authors themselves recognized as a potential limitation of their research.
“Understandably, they were worried about life-threatening adverse events, and that’s fine,” she said. But for patients with arthritis who flare, their events are usually grade 2 or even grade 1 and therefore not captured or analyzed in the study. “This does not really address the risk of flare in an RA patient.”
She also questioned their grouping of AIDs, with a bevy of rheumatic diseases categorized as one cluster and the “other” group being particularly broad in its inclusion of “all AIDs not listed” — though only eight patients were placed into that group.
That said, the researchers relied on an oncology database, not one aimed at AID or adverse events. “The numbers are so much bigger than any other study in this area that’s been done,” she said. “It’s both a strength and a weakness of this kind of database.”
Indeed, the authors considered their use of nationwide, population-based data from the DMTR a benefit, calling it “a strength of our approach.”
The DMTR was funded by a grant from the Netherlands Organization for Health Research and Development and sponsored by Bristol-Myers Squibb, Novartis, Roche Nederland, Merck Sharp & Dohme, and Pierre Fabre via the Dutch Institute for Clinical Auditing.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.
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