Optimal treatment strategy with nilotinib for patients with newly diagnosed chronic-phase chronic myeloid leukemia based on early achievement of deep molecular response (MR4.5 ): The phase 2, multicenter N-Road study

Abstract

For patients who have chronic myeloid leukemia (CML), one of the primary treatment options is administration of nilotinib 300 mg twice daily (BID). In previous studies which compared outcomes associated with nilotinib or imatinib treatment, nilotinib achieved a higher rate of deep molecular response (MR). We conducted a phase II, open-label, multicenter study to investigate an intrapatient nilotinib dose-escalation strategy for patients with newly diagnosed chronic-phase (CP) CML based on early MR^4.5 achievement. The primary study endpoint was achievement of MR^4.5 by 24 months following the initiation of nilotinib 300 mg BID. Fifty-three patients were enrolled, 51 received nilotinib, and 37 completed the treatment. An increase in the nilotinib dose (to 400 mg BID) was allowed when patients satisfied our criteria for no optimal response at any time point. The median (range) dose intensity was 600 (207-736) mg/day. Of 46 evaluable patients, 18 achieved an optimal response and 28 did not. Of the latter, nine patients underwent dose escalation to 400 mg BID, and none achieved MR^4.5 . The remaining 19 patients could not undergo dose escalation, 12 (63%) because of adverse events (AEs), and 7 (37%) for non-AE related reasons. Four of these patients achieved MR^4.5 . The MR^4.5 rate by 24 months was 45.7%. The progression-free, overall and event-free survival were each 97.6%. No new safety concerns were observed. Our findings support the use of continuous nilotinib at a dose of 300 mg BID for newly diagnosed patients with CML-CP.

Keywords: chronic myeloid leukemia; early deep molecular response; nilotinib.