Increases in Melanoma Risk in Patients Treated with Biologic Therapy Not Ruled Out

Findings published in JAMA Dermatology suggested that clinically important increases in melanoma risk in patients treated with biologic therapy for common inflammatory diseases cannot yet be ruled out.

However, the researchers also indicated that future studies with larger patient numbers that adjust for key risk factors are necessary to resolve the issue of long-term safety of biologic therapy.

“We advocate for more large, well-designed studies of this issue to be performed to help improve certainty,” the authors wrote. “Prospective cohort studies using an active- comparator, new-user study design providing detailed information on treatment history, concomitant treatments, biologic and conventional systemic treatment duration, recreational and treatment-related UV exposure, skin color, and date of melanoma diagnosis are required to help improve certainty. These studies would also need to account for key risk factors and the latency period of melanoma.”

The objective of this study was to determine whether biologic treatment of inflammatory bowel disease (IBD), rheumatoid arthritis (RA), or psoriasis is associated with an increased risk of melanoma compared with conventional systemic therapy.

Embase, MEDLINE, and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched for eligible studies. Researchers included randomized clinical trials, cohort studies, and nested case-control studies quantifying the risk of melanoma in biologic-treated patients with IBD, RA, and psoriasis compared with patients treated with conventional systemic therapy. 

Overall, 34,029 biologic-treated patients and 135,370 biologic-naïve patients treated with conventional systemic therapy across a total of 7 cohort studies were evaluated. 

Biologic treatment was found to be positively associated with melanoma in patients with IBD (pooled relative risk [pRR], 1.20; 95% CI, 0.60-2.40), RA (pRR, 1.20; 95% CI, 0.83-1.74), or psoriasis (hazard ratio, 1.57; 95% CI, 0.61-4.09) compared with those who received conventional systemic therapy, though the differences were not statistically significant. However, adjustment for other risk factors was absent from most studies.

The researchers indicated that future population-based studies will need to consider the rapidly changing landscape of biologic treatment in IBD, RA, and psoriasis. For instance, the introduction of biologic therapies that target interleukins 6, 23, and 17 has expanded the available treatment options for patients initiating biologic therapy.

Additionally, the researchers indicated that the introduction of TNF inhibitor (TNFI) biosimilars in this space may lead to greater access for patients requiring these treatments, with possible earlier intervention in patients with IBD and psoriasis currently treated with non-biologic systemic therapy.

“Future studies should consider the various biological mechanisms of these therapies, their potential role in the development of melanoma, and how exposure to multiple classes of biologic therapies might affect a patient’s risk of melanoma,” the authors wrote. “To account for confounding by this indication, studies should compare patients treated with TNFIs with patients treated with the newer biologics and those treated with more than 1 type of biologic.”

Notably, the main limitation of this systemic review and meta-analysis was the small number of disease-specific studies that examined the risk of melanoma between biologic-treated patients and patients treated with conventional systemic therapy. Therefore, any future update of the study through the inclusion of newly published studies may produce significantly different risk estimates than those herein reported. 

References:

Esse S, Mason KJ, Green AC, Warren RB. Melanoma Risk in Patients Treated with Biologic Therapy for Common Inflammatory Diseases. JAMA Dermatology. doi:10.1001/jamadermatol.2020.1300.