Recurrent Rhabdomyolysis During Dabrafenib and Trametinib Therapy in BRAF V600E-Mutated Non-Small Cell Lung Cancer: A Case Report

BRAF V600E mutations are established actionable oncogenic drivers in non-small cell lung cancer, and combined BRAF and MEK inhibition with dabrafenib plus trametinib has demonstrated clinical efficacy. Although pyrexia, fatigue, and gastrointestinal symptoms are common adverse events associated with this regimen, rhabdomyolysis is a rare but potentially serious complication, and its optimal management has not been well reported. Here, we discuss the case of a man in his 70s with recurrent BRAF V600E–mutated lung adenocarcinoma who was treated with dabrafenib (300 mg/d) and trametinib (2 mg/d). One month after treatment initiation, mild elevations in creatine kinase (CK) and serum creatinine levels were observed, which resolved following temporary treatment interruption and a one-step dose reduction, while tumor regression was maintained. Seven months later, the patient developed asymptomatic but severe rhabdomyolysis, with a peak CK level of 9,938 U/L and a mild increase in serum creatinine level. Laboratory abnormalities rapidly normalized after treatment cessation and intravenous hydration. Given the sustained treatment response and the patient’s preference to continue therapy, dabrafenib and trametinib were cautiously reintroduced at a two-step reduced dose without recurrence of rhabdomyolysis. Tumor control was preserved, and the patient remained progression-free for more than one year after treatment initiation. This case highlights the possibility of recurrent rhabdomyolysis during dabrafenib and trametinib therapy and suggests that careful monitoring and individualized dose modification may allow continued treatment in selected patients.