Recent data suggest that second-generation tyrosine-kinase inhibitor (TKI) dasatinib and nilotinib can be responsible for increased non-hematologic adverse events in comparison to imatinib. In particular, there are a few reports of severe peripheral arterial occlusive disease (PAOD) and other vascular occlusive events (infarction) in patients receiving nilotinib. With this in mind we retrospectively evaluated incidence of PAOD or other vascular occlusive events in our cohort including 82 consecutive chronic myeloid leukemia (CML) patients treated at our institution with imatinib alone (n=55) or nilotinib as first-line (n=17) or second-line treatment after imatinib failure (n=10). After a median time of exposition to nilotinib of 24 months (range, 7–34 months) 4 (14.8%) out of 27 patients developed an episode of severe and previously unrecognized PAOD or other vascular occlusive events (2 PAOD, 1 myocardial infarction, 1 ictus). All 4 patients were more than 60 years old and 3 out of 4 were male while obesity was never observed. A history of nicotine abuse could be found in 2 out of 4 patients. The same applied when we looking for the presence of arterial hypertension (2/4) or dyslipidemia (2/4). When 55 patients treated with imatinib were analyzed for PAOD or other vascular occlusive event incidence we detected only one patient who experienced myocardial infarction after 135 months of therapy.
We then evaluated the likelihood of developing PAOD in the subset of patients treated only with imatinib and in those who received nilotinib, respectively. The projected 10-year actuarial probability of remaining PAOD-free was 100% in the imatinib group and 67% in the nilotinib group (HR, 14.6; P=0.0008). Interestingly, the two patient cohorts were alike with respect to age (P=0.76), gender (P=0.80), number cardiovascular risk factors (P=0.62) and body mass index (P=0.59). The only difference we observed was a significantly longer exposition to drug among patients treated only with imatinib in comparison to those who received nilotinib (P<0.001).
In conclusion this study although hampered by the relatively small patient number suggests that in CML front-line and second-line treatment should be adapted to the individual situation in each patient. Parameters related to risk of developing TKI-associated adverse PAOD events should be considered before choosing a second-generation TKI.
No relevant conflicts of interest to declare.
Asterisk with author names denotes non-ASH members.