The Bone Phenotype and Pain Response to Pamidronate in Tyrosine Kinase Inhibitor-Treated Chronic Myelogenous Leukemia.

Tyrosine kinase inhibitors (TKIs) have been linked to bone pain and linear growth attenuation in children with TKI-treated chronic myelogenous leukemia (CML). We describe the skeletal phenotype in an 11-year-old boy with chronic bone pain due to TKI-treated CML, including his response to intravenous (IV) pamidronate. This boy was diagnosed with Philadelphia chromosome-positive CML at 4 years of age. He was treated with imatinib for 3 years, followed by dasatinib for 4 years. At age 11 years, he was seen in a bone health clinic with a 4-year history of leg pains that necessitated regular nonsteroidal anti-inflammatory drugs (NSAIDS) and downward crossing of height percentiles (from the 25th to fifth). The bone volume/tissue volume Z-score was +1.6 for a trans-iliac bone biopsy specimen, with an increase in trabecular number (Z-score, +3.1). Bone formation and resorption parameters on trabecular surfaces were within normal limits. Tibia volumetric bone mineral density (BMD) and bone geometry were normal by peripheral quantitative computed tomography, areal BMD Z-scores were average or above average at multiple skeletal sites by dual-energy x-ray absorptiometry, and tibia length Z-score was reduced (-2.3). Growth- and bone-related biochemical studies were unremarkable except a low serum alkaline phosphatase level. His bone pain resolved completely after 9 months of low-dose IV pamidronate. An increase in trans-iliac trabecular number and shortened tibia were the main skeletal features in this patient. Short-term IV pamidronate was effective for mitigating bone pain, allowing this boy to continue receiving dasatinib without the need for chronic NSAID therapy.