Impact of body mass index on the severity of bexarotene‐associated hypertriglyceridemia: A post hoc analysis of an open‐labeled clinical study of combined bexarotene and phototherapy in Japanese patients with cutaneous T‐cell lymphoma

Bexarotene is an effective oral drug for the treatment of cutaneous T‐cell lymphoma, but careful management is required due to its various side effects. In particular, hypertriglyceridemia often requires a reduction or even suspension of bexarotene therapy. The risk factors of bexarotene‐associated severe hypertriglyceridemia are not clear. Here, we conducted a post hoc analysis of the data from our previous clinical trial, which confirmed the efficacy and safety of combined bexarotene and phototherapy, to evaluate the effect of body mass index on bexarotene‐associated hypertriglyceridemia. Twenty‐five subjects were divided into two subgroups: normal and underweight (body mass index [BMI] <25 kg/m2 group) and overweight and obese (BMI ≥25 kg/m2 group) patients. The overall incidence of hypertriglyceridemia was 81.3% (13/16) in the BMI <25 kg/m2 group and 88.9% (8/9) in the BMI ≥25 kg/m2 group. The incidence of grade ≥3 hypertriglyceridemia (≥500 mg/dL) was 7.7% (1/13) in the BMI <25 kg/m2 group and 7/8 (87.5%) in the BMI ≥25 kg/m2 group (P < 0.001). Consequently, dose reduction in the BMI ≥25 kg/m2 group was larger than that in the BMI <25 kg/m2 group. The bexarotene‐induced change in the serum triglyceride concentration was significantly increased in cutaneous T‐cell lymphoma patients with a higher body mass index (ρ = 0.508, P = 0.009). The area under the curve was 0.886 (95% confidence interval 0.748–1.000, P = 0.002). With a body mass index cut‐off of 24.85 kg/m2, the sensitivity and specificity for identifying grade ≥3 hypertriglyceridemia were 0.875 and 0.882, respectively. The present findings suggest that BMI ≥25 kg/m2 is a risk factor for bexarotene‐associated severe hypertriglyceridemia, therefore overweight and obese patients treated with bexarotene should receive lipid‐lowering drugs prophylactically. Further studies for optimizing the initial bexarotene dose in such patients are required.