Hair and nail abnormalities are commonly associated with the Bruton tyrosine kinase inhibitor ibrutinib and often appear several months after initiating treatment, according to a brief report published in JAMA Dermatology.1
Ibrutinib was initially approved by the US Food and Drug Administration in 2013 and is indicated for the treatment of mantle cell lymphoma, chronic lymphocytic leukemia (CLL), and Waldenström’s macroglobulinemia. Although the drug is well tolerated overall, long-term treatment is required and intolerable toxicities do occur. Furthermore, little is known regarding its cutaneous adverse effects.
Therefore, researchers sought to characterize the hair and nail manifestations associated with the long-term use of ibrutinib in patients with CLL.
For the phase 2 study, researchers enrolled 66 patients with CLL who all received ibrutinib. Of those, 43 were men and 23 were women, and their ages ranged from 55 to 85 years.
Results showed that 67% reported brittle fingernails at a median of 6.5 months after initiation of ibrutinib therapy. In addition, 23% developed brittle toenails after a median of 9 months of treatment. Twenty-six percent of patients also reported textural hair changes at a median of 9 months of therapy.
It remains unknown as to how ibrutinib causes hair and nail abnormalities. One potential explanation is that ibrutinib may bind to cysteine 481 in those areas and alter the cysteine-rich proteins of hair and nails.
1. Bitar C, Farooqui MZH, Valdez J, et al. Hair and nail changes during long-term therapy with ibrutinib for chronic lymphocytic leukemia [published online ahead of print March 16, 2016]. JAMA Dermatol. doi:10.1001/jamadermatol.2016.0225.