Nilotinib induced hair repigmentation

Kockerols et al describe a case report where a 51 year old man's hair turned from grey to brown (1):

• a 51-year-old man with chronic myeloid leukaemia visited the oncology clinic for routine follow-up
• treatment with nilotinib, a tyrosine kinase inhibitor (TKI), had been initiated 18 months earlier
  • during that time, the patient had noticed the gradual repigmentation of his grey hair to its original colour
  • during the same period, he had not started any other new medications and had used no hair-colouring products
  • no other changes in his hair, skin, or mucosal pigmentation were observed
  • molecular testing showed a deep molecular response
  • a diagnosis of medication-induced hair repigmentation due to the use of a tyrosine kinase inhibitor was made
  • given the response of the leukaemia to treatment with nilotinib, it was continued, and the patient's hair remained brown.

Nilotinib is an oral TKI, rationally designed to overcome imatinib resistance in CML (chronic myeloid leukaemia)

• development of TKIs for the treatment of CML was driven by the knowledge that the protein kinase BCR-ABL, encoded by the BCR-ABL fusion oncogene, is constitutively activated in patients with this disease (2)
  • the BCR-ABL fusion oncogene is present in 95% of patients with CML and is the result of a chromosomal aberration known as the Philadelphia chromosome (Ph), which arises from the accidental fusion of the BCR gene with the gene encoding for the intracellular non-receptor tyrosine kinase c-ABL
    • in normal cells, the activity of ABL1 is tightly controlled; in contrast, BCR-ABL fusion proteins have constitutive catalytic activity leading to cell transformation and ultimately uncontrolled cellular proliferation and reduced apoptosis
    • based on this premise, BCR-ABL kinase represents a logical therapeutic target for the development of drugs to treat CML

There is also an association with nilotinib-induced keratosis pilaris described (3)

Reference:

1. Kockerols CCB, Westerweel PE. Hair Repigmentation Induced by Nilotinib. N Engl J Med. 2022 Aug 6. doi: 10.1056/NEJMicm2119953
2. Blay JY, von Mehren M. Nilotinib: a novel, selective tyrosine kinase inhibitor. Semin Oncol. 2011 Apr;38 Suppl 1(0 1):S3-9. doi: 10.1053/j.seminoncol.2011.01.016.
3. Leong WM, Aw CW. Nilotinib-Induced Keratosis Pilaris. Case Rep Dermatol. 2016 Apr 21;8(1):91-6. doi: 10.1159/000445676.