The PDGFRB protein has already been a therapeutic target in haematology and oncology since the early 2000s, initially in the treatment of certain leukaemias with hyperactivation of the protein in affected cells, with well-known efficacy and safety profiles. Drugs that target this protein are called Tyrosine Kinase Inhibitors (TKIs) because they target the hyperactivation of this protein. TKIs therefore appear to be an interesting therapeutic alternative in KOGS/PS, at least to limit progression of the disease.
To date, there is no marketing authorisation to prescribe a TKI treatment for KOGS/PS. This prescription can be made on a compassionate basis, which is available in some countries, but not others. Of the thirty or so known patients worldwide, 7 are currently being treated with TKI. Several have shown clinical improvement. One patient experienced serious side effects, with a reduction in growth rate at the age of 9. This side effect resolved as the dose of TKI was reduced. The other patients treated had no or only mild side effects. However, their short follow-up limit our knowledge on the long-term efficacy and safety of TKIs.