Risks of attempting TFR

In clinical trials, including EURO-SK⁴ and ENESTFreedom, 25–30% of patients who stopped taking any TKI experienced a ‘TKI withdrawal syndrome’ – pain localised to various parts of the body, including the hips, shoulders and extremities, resembling polymyalgia rheumatica. Most patients can manage these symptoms with paracetamol and non-steroidal anti-inflammatory drugs, although some require steroids. It is thought that off-target effects of TKIs in inhibiting the receptor tyrosine kinase cKIT relieves some joint inflammation, which returns upon TKI withdrawal. Supporting this link, some patients with spondyloarthritis achieve pain relief with nilotinib.