Incidence of Vascular Thrombotic Events in 183 Consecutive Patients Treated with Nilotinib: A Single Centre Experience

Introduction

The spectrum of adverse events occurring in nilotinib is broadly similar to that of other tyrosine kinase inhibitors but recent reports suggest an increase in the incidence of vascular thrombotic events (VTE) compared to imatinib. Many patients treated with ponatinib, where the association of VTE with treatment is now widely accepted, have previously received nilotinib and it remains unclear as to whether the adverse events are a result of the cumulative use of the two drugs. It is important to clearly delineate the risk of VTE with nilotinib in order to estimate risk and provide better information for patients.

Methods

We conducted a chart review to identify adverse events in 183 consecutive patients who received nilotinib in our institution from February 2006 until June 2014. Patients were to be considered at risk of side effects in they had received at least 24 hours of treatment. Data were collected from out-patient consultations in which side effects and their severity were self-reported and recorded in the medical case notes. The cohort contained 93 women and 90 men and had a median age of 56 years (range 21-93). 8% of patients received nilotinib as first line therapy: 46% and 39% respectively were treated after failure of imatinib only or imatinib and dasatinib . The remainder were treated for relapse post allogeneic transplant. Of those who were treated after one or two prior tyrosine kinase inhibitors (TKI), 57% and 43% were intolerant or resistant respectively.

Results

The median duration of treatment with nilotinib was 714 days (range 10 -2816 days). Information was available for pre-existing cardiovascular risk factors in 93% of patients and were present in 59%. We recorded 20 occurrences of VTE in 10% of patients with 9 (5%), 7 (4%) and 4 (2%) episodes of myocardial ischaemia, peripheral arterial occlusive disease and cerebrovascular disease respectively. Only one patient without pre-existing cardiovascular risk factors experienced a VTE, The median age of patients with VTE was 67 years (range 35-79) compared to 55 years (range 21-93) in those without VTE. In contrast to previously reported results VTE were more common (18%) in patients who had received two prior TKI compared to 8% in those who had been treated with a single TKI and 7% who received nilotinib upfront. 75% of VTE occurred in patients who have been treated with nilotinib for more than 2 years but this may in part be because of continuation of treatment at a time of lack of awareness of the association of nilotinib with VTE. The remaining adverse events reported on nilotinib were in accordance with published data. Side effects occurring in >10% of patients are given in the table.

Conclusions

The incidence of VTE in patients treated with nilotinib in our institution was 10%. VTE was more frequent in older patients, in those with pre-existing cardiovascular risk factors and in those who received prolonged therapy with nilotinib. Without a suitable control group matched for age and cardiovascular risk factors it is difficult to provide an accurate estimate of any potential increased risk of treatment with nilotinib. Nevertheless caution must be exercised in older patients with pre-existing risks for VTE and appropriate counselling and monitoring provided.