The report appears in Arthritis & Rheumatism online October 10,and the results echo those reported last month in another study on biologic therapy for rheumatoid arthritis, published in JAMA (see Reuters Health report on September 4, “Some reassuring data on cancer risk with biologic therapy for RA”: SOURCE: http://bit.ly/Tj7ASV).
“Like the findings of the JAMA paper, we did not observe an increased risk of cancer early in the course of treatment among patients treated with biologic response modifiers,” commented Dr. Kevin Haynes, the lead author of the current study, in an email to Reuters Health. “Our work extends the work of the reviews of randomized controlled trials into real world populations, notably those with Medicaid and insurance coverage.”
Dr. Haynes, with the University of Pennsylvania, Philadelphia, and colleagues note that there have been reports of an increased incidence lymphoma and other malignancies with some TNF-Is, but other studies have found no significant increase in cancer risk with these agents.
To investigate further, the team identified patients with autoimmune diseases who initiated treatment with TNF-Is or comparator drugs, using data from four sources that included a range of demographics — seniors on Medicare, low income Medicaid beneficiaries, those with private health insurance in northern California, and a low income elderly population from the Northeast.
The study included 29,555 patients with rheumatoid arthritis, 6,357 patients with inflammatory bowel disease, 1,486 patients with ankylosing spondylitis, 1,298 with psoriasis and 2,498 with psoriatic arthritis. Median follow up times were relatively short, ranging from about 3 months to about 1.5 years.
Rates of solid cancers were not significantly higher in the TNF-I group than in the comparator group across all immune-mediated diseases, the investigators found. Specifically, the hazard ratio for developing solid cancer during TNF-I treatment compared to disease-specific alternative therapy was 0.80 in rheumatoid arthritis, 1.42 in IBD, 0.03 in ankylosing spondylitis, 0.58 in psoriasis and 0.74 with psoriatic arthritis.
For all diseases where there were a sufficient number of events to estimate hazard ratios, “no significant increase risk was observed for any lymphoma, any leukemia or lymphoma, or NMSC (non-melanoma skin cancer),” according to the report.
The authors also looked into the relative hazard for the 10 most common cancers in the United States among the RA patients, as this was the group with the most data. Again, there was no significant treatment-related difference in risk for any of the cancers.
“In conclusion, we did not observe an increased incidence of cancer early in the course of treatment among patients treated with TNF-I in this large cohort study across multiple patient populations,” Dr. Haynes and colleagues write. However, they point out, “The outcomes of long term therapy will require further study in these or other cohorts.”