Symptomatic mucocutaneous toxicity of hydroxyurea in Philadelphia chromosome-negative myeloproliferative neoplasms: the Mister Hyde face of a safe drug.

Background: The current study was conducted to evaluate severe mucocutaneous toxicity during treatment with hydroxyurea (HU) in a large cohort of patients with Philadelphia chromosome-negative myeloproliferative neoplasms (MPN).
Methods: Among 993 consecutive patients newly diagnosed with MPN at 4 centers in Rome between January 1980 and December 2009, 614 patients (277 men and 337 women with a median age of 64.4 years [interquartile range (IR), 54.4 years-72.7 years]) received HU. HU was administered as first-line treatment in 523 patients (85.2%) and as ≥ second-line treatment in 91 patients (14.8%).
Results: Mucocutaneous toxicity was reported in 51 patients (8.3%) after a median period from the initiation of HU treatment of 32.1 months (IR, 10.5 months-74.6 months) and a mean HU dose of 1085 mg (± 390 mg); 30 patients (58.8%) developed a painful ulcerative skin toxicity, mainly located in the perimalleolar area; 11 patients (21.6%) had oral aphthous ulcers; and 10 patients (19.6%) developed a nonulcerative skin toxicity with erythema and skin infiltration. After the mucocutaneous toxicity occurred, HU treatment was continued at the same dose in 5 patients (9.8%), reduced in 12 patients (23.5%), and temporarily discontinued in 7 patients (13.7%); the remaining 27 patients (52.9%) required a permanent drug discontinuation. After a median period of 4.3 months (IR, 2.4 months-9.0 months) from the onset of the skin toxicity, 39 patients (76.5%) had a complete resolution and 12 patients (23.5%) had improvement without complete resolution.
Conclusions: Mucocutaneous toxicity during HU treatment is more common than expected and may present with different clinical features. Moreover, it often requires a permanent drug discontinuation and only a partial resolution is reported to occur in approximately 25% of patients.
(Copyright © 2011 American Cancer Society.)