Biologics and cancer risk: Results of a new Danish study

New findings suggest that biologics do not increase the risk of a second malignancy in people with rheumatoid arthritis (RA) and a history of cancer. The data were presented at the 2017 American College of Rheumatology/Association of Rheumatology Health Professionals (ACR/ARHP) Annual Meeting in San Diego, CA.

Biologic disease-modifying antirheumatic drugs, or biologics, are designed to control RA disease activity and prevent joint damage in RA patients. The class of drugs has been studied for 15 years, but there is still concern that these medications could increase the risk of malignancy in patients with a history of cancer.

A Danish team of researchers conducted a study of 1,678 people with RA from a national registry to determine if biologic use increased the risk of a second cancer diagnosis in individuals who have had cancer. The study also looked at mortality rates among the subjects.

“Second malignancy is an increasing challenge, as the survival after the first, primary tumor has improved substantially for most types of cancer,” says Lene Dreyer, MD, associate professor of rheumatology at the University of Copenhagen and a lead author of the study. “The concern for second malignancy or cancer recurrences in patients with a history of cancer diagnosis has led to some reluctance in treating this subset of arthritis patients with biologics, especially TNF-inhibitors. Consequently, some RA patients with a previous cancer are suffering from inadequate treatment of their arthritis.”

Rheumatoid arthritis patients who had a primary cancer diagnosis were selected from the DANBIO Registry, a national medical records database in Denmark, from 2000 to 2011. The researchers analyzed their cases to determine the hazard ratio (HR) for secondary malignancy and deaths among this population.

Of the study participants, 190 received biologics only before their primary cancer diagnosis, 220 received biologics only after their primary cancer diagnosis, 92 received biologics both before and after their primary cancer diagnosis, and 1,176 were never treated with biologics.

Among the 502 patients who received a biologic at any time, the HR for developing a second malignancy was 1.11; the HR for those who were never treated with a biologic was 1.00. This was not a statistically significant increase in the risk for a second malignancy.

Researchers looked at mortality rates among RA patients with a history of cancer, but were unable to draw a clear conclusion about significant increases. When the data were adjusted for age, gender, calendar time, site of the cancer, and extent of the disease, the HR for death was 1.20 among the RA patients treated with a biologic only before their cancer diagnosis, compared with 1.00 for those who never received a biologic.

Patients treated with a biologic only after their cancer occurred had an HR for death of 1.36, and those who received biologics both before and after their cancer diagnosis had an HR for death of 1.22.

“It is reassuring that these results indicate no increased risk of a second malignancy in RA patients with a past cancer who used biologic therapy, and that was no major indication of an increased mortality rate among users of these medications,” said Dr. Dreyer. “However, the number of patients who suffered a second malignancy was small, so our statistical analyses must be interpreted with caution. Further studies are required to confirm our findings. In the meantime, [our data] provide some reassurance that biologics don’t pose an immediate danger in patients with a history of cancer.”