Severe toxic rhabdomyolysis under combined palbociclib and simvastatin treatment: A case report

Abstract

We report the fourth described case of severe toxic rhabdomyolysis occurring in an 81-year-old woman caused by the concomitant administration of palbociclib taken at the usual dosage (125 mg per day) and simvastatin. To the best of our knowledge, this is the first reported case successfully treated by plasma exchanges, with complete functional recovery within two months. The severity of this case justifies further consideration of pharmacokinetic interactions between palbociclib or other CDK-4-6 inhibitors and statins, which potentially increase the risk of an adverse event.

Keywords: interaction; myositis; palbociclib; plasmatic exchange; rhabdomyolysis; simvastatin.

Figure 1

Evolution of CPK and ASAT after three plasma exchange cycles (red arrows). The natural evolution of CPK and ASAT levels before initiation of plasmatic exchanges is symbolized by red arrows. As illustrated, three plasmatic exchanges led to a significant decrease in both CPK and ASAT levels.

Figure 2

(A) Magnetic Resonance Imaging (MRI) of muscles of lower limbs, T1 Coronal and T2 axial reconstruction. MRI shows pathological bilateralhypersignal of proximal muscles: gluteal muscles, medial gastrocnemius muscles, solar muscles with relative respect of semitendinosus muscles. (B) Immuno-histo-chemical staining of the muscle biopsy. Standard muscle biopsy stain exhibiting muscle atrophy, degeneration, necrosis, macrophagic infiltration and muscle fiber irregularity.