Sunitinib

Receptor tyrosine kinase inhibitor.

Sunitinib (like sorafenib) is a targeted tumor therapy and blocks the tyrosine kinase of the receptors PDGFR (platelet-derived-growth-fctor). Furthermore, sunitinib inhibits the tyrosine kinase of VEGFR (vascular endothelial growth factor - see below VEGF) and c-Kit. It also inhibits some serine threonine kinases (multi-kinase inhibitors). Sunitinib thus switches off the signalling effect of growth factors at the molecular level, which the tumour needs for its growth.

Used to treat non-resectable and/or metastatic malignant gastrointestinal stromal tumors (GIST) when treatment with imatinib (Gleevec) has failed due to resistance or intolerance. Another indication is metastatic renal cell carcinoma.

The major serious side effects of sunitinib are pulmonary embolism (1% of cases), thrombocytopenia (1%), neutropenia with fever (0.4%), and hypertension (0.4%). The most commonly reported adverse events were fatigue/exhaustion (the so-called fatigue syndrome), which affects about one-third of patients. Frequently (>20% of cases), diarrhoea, nausea, stomatitis continue to occur.

Typical side effects on the skin organ are observed from the 3rd-4th week of treatment:

• Hand-foot syndrome
• Xerosis of the skin
• diffuse effluvium with alopecia
• subungual haemorrhages (splinter hemorrhages)
• Depigmentation of skin and hair
• periocular edema.

Sutent®

1. Wozel G et al (2010) Undesirable dermatological effects in therapeutic inhibition of the VEGF pathway. JDDG 8: 243-249