medwireNews: 

Over half of chronic myeloid leukaemia (CML–CP) patients in the chronic phase who discontinue second-line nilotinib therapy after achieving a sustained deep molecular response (MR) remain in treatment-free remission (TFR) 48 weeks later, suggests research presented at the European Hematology Association congress in Copenhagen, Denmark.

“ENESTop provides the largest set of prospective TFR data to date in patients with CML–CP who achieved sustained deep MR with second-line nilotinib”, said Timothy Hughes, from the University of Adelaide in South Australia, and co-authors.

In all, 126 of the 163 patients enrolled in the trial met criteria for discontinuation, defined as having typical BCR–ABL1 transcripts, and the achievement and maintenance of MR^4.5 (BCR–ABL1 ≤0.0032% or less on the International Scale) for 1 year after switching from imatinib to nilotinib therapy.

The patients had received a median of 87.7 months of tyrosine kinase inhibitor (TKI) therapy and 53.0 months of nilotinib before discontinuing treatment.

After 48 months 57.9% of patients remained in TFR, with 53.2% retaining MR^4.5 at this time.

Fifty-one of the 53 patients who lost their major molecular response (MMR, BCR–ABL1 ≤0.1%) or MR⁴ (BCR–ABL1 ≤0.01%) during TFR – mostly during the first 6 months – restarted nilotinib therapy. Of these patients, 98.0% regained MMR or better, with 94.1% regaining MR⁴ or better and 92.2% MR^4.5 after a median of 12.0 and 13.1 weeks, respectively.

The majority of patients experienced adverse events during the 52 weeks of nilotinib (77.0%) and the 48 weeks of TFR follow-up (73.8%). Most haematological and biochemical events were more common during nilotinib therapy, and cardiovascular events and rashes only occurred during active treatment.

However, musculoskeletal pain was more frequent during TFR, at 42.1% versus 14.3% during therapy, and the researchers note that the estimated median duration of first musculoskeletal pain-related event was not reached by time of data cutoff.

None of the patients progressed to accelerated phase or blast crisis.

Hughes et al concluded: “These results from ENESTop, together with those from ENESTcmr showing a great likelihood of MR^4.5 with a switch to nilotinib, suggest that a higher proportion of patients switching to nilotinib will achieve TFR compared with patients continuing on imatinib.”

By Lynda Williams, Senior medwireNews Reporter

Meeting website

{rscomments off}

medwireNews is an independent medical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2016