Melanoma, Squamous Cell Carcinoma and Merkel Cell Carinoma in JAK inhibitor Users

It is currently thought that JAK inhibitors may increase the risk for non melanoma skin cancer as well as melanoma.

Authors from France set out to examine the risk of various types of skin cancer by looking deeper into the VigiBase® database. The VigiBase is the World Health Organization international database of suspected adverse drug reactions. The goal of searching the database was to see if there were any disproportionality signals of skin cancers from use of JAK inhibitors.

The authors examined data for melanoma, squamous cell carcinoma and merkel cell carcinoma. A positive IC value indicates that a particular JAK inhibitor is reported more often with the cancer than expected, based on all the reports in the database.

A disproportionality signal was found positive for squamous cell carcinoma with ruxolitinib (IC025=3.92) and tofacitinib (IC025=0.82), for melanoma with ruxolitinib (IC025=0.81) and tofacitinib (IC025=0.74), and Merkel cell carcinoma with ruxolitinib (IC025=4) and tofactinib (IC025=1.01) and baricitinib (IC025=0.53).

Comment

This is a helpful report that reminds us that we need to include skin cancer risk in our counselling for JAK inhibitor side effects. In addition, it is important to perform a skin examination before starting JAK inhibitors and then again periodically in follow-up.

Rates of squamous cell carcincoma, melanoma and Merkel cell carcinoma may potentially be increased by use of JAK inhibitors. Tofacitinib and ruxolitinib have been on the market longest and seem to have an association with all three cancers. It is interesting that the rare Merkel cell carcinoma could potentially be increased with use of all three JAKs studied here. It’s also interesting to me that we are able to detect a disproportionality signal after the short duration that baricitinib has been on the market.

Additional good studies are needed to clarify the risk.

REFERENCE

Jalles et al. Skin cancers under Janus kinase inhibitors: A World Health Organization drug safety database analysis. Therapie. 2022 May 7;S0040-5957(22)00092-0.