Tyrosine kinase inhibitor (TKI) therapy discontinuation in patients with CML in chronic phase: A US clinical practice perspective.

Abstract

7052 Background: This study assessed TKI discontinuation practice in the US before the publication of new practice guidelines in November 2016 including recommendations on TKI discontinuation for patients (pts) with CML in chronic phase (CML-CP). Methods: From 10/12/2016 to 11/9/2016, 300 US oncologists/hematologists completed a survey on the reasons for TKI discontinuation in pts with CML-CP, their perspective on adequate response pts should achieve before considering TKI discontinuation (minimum response to TKI, response duration, and TKI therapy duration), and post-discontinuation CML monitoring. Results: One third of participating physicians reported having attempted TKI discontinuation (102 of 300); 66 did so outside of a clinical trial. Physicians who reported TKI discontinuation were more likely to practice in academic centers; were more experienced clinicians ( > 10 years in practice); and followed a larger number of CML pts vs those who did not. Among the 66 physicians, the majority would consider TKI discontinuation for medical reasons (76% adverse events, 47% pregnancy planning), with fewer for economic reasons (35%); 12% reported they would consider it for all of their pts who achieve an adequate response. There was no consensus on the minimum response achieved (56% consider a decrease in BCR-ABL of ≥4.5 log, 21% 3 log, and 11% 1 log), the minimum response duration (29% 3 yrs, 24% 2 yrs, and 20% 1 yr), and the minimum TKI therapy duration (44% 3yrs, 20% 2 yrs, 19% 1 yr) before TKI discontinuation. There was no consensus on the frequency of CML monitoring post-discontinuation with < 10% of physicians considering monthly molecular monitoring in the first year. Conclusions: TKI discontinuation in pts with CML-CP responding to TKI was attempted outside of clinical trials without clear guidelines. Conditions under which TKI therapy was discontinued differed from new recommended practice guidelines, which may have resulted in discontinuation where deep response may not be achieved and disease not adequately monitored. The recommended practice guidelines need to be communicated to physicians as TKI discontinuation is likely to be conducted in a broader population.