Low-Dose TKIs Before Therapy Cessation Leave Treatment-Free Remission Rates Unscathed in CML
Retrospective study findings demonstrated that, in patients with chronic myeloid leukemia (CML), administration of low-dose tyrosine kinase inhibitors (TKIs) before TKI cessation does not impair treatment‐free remission (TFR; Cancer. 2020 May 27. Epub ahead of print).
Lead investigator Emilie Cayssials, MD, Service d'Oncologie Hématologique et Thérapie Cellulaire, CHU Poitiers, France, and colleagues hypothesized that low‐dose TKIs given to patients with CML prior to treatment discontinuation do not impair TFR in those with deep molecular responses (DMRs, ≥MR4).
To evaluate this theory, Dr Cayssials et al analyzed 77 patients with CML who discontinued TKI therapy, including 26 who had been given low-dose TKIs before TKI treatment cessation. The patients in the study were to be exposed to TKI therapy for ≥5 years and low-dose TKIs for ≥1 year, and to have DMRs for ≥2 years.
Overall, 61.5% of patients in the low-dose TKI arm received second-generation TKIs, and dose reductions were ≥50% for 65.4% of patients. The researchers deemed major molecular response (MMR) loss as a trigger for therapy re-initiation.
With a median 61.5 months of follow-up, patients in the full-dose and low-dose TKI arms had 12-month TFRs of 56.8% and 80.8%, respectively. The 60-month TFRs were 47.5% and 58.8%, respectively.
Across all patients in the study, the median time to molecular recurrence (≥MMR) from TKI discontinuation was 6.2 months. Of note, MMR was achieved quickly in all patients after resumption of TKI therapy.
According to the investigators, these findings were independent from dose reduction and potential interferon-α pretreatment.
“This retrospective study shows that TFR was not impaired by low-dose TKI regimens before TKI cessation in Patients with CML,” Dr Cayssials and colleagues wrote.
“Nevertheless, prospective randomized clinical trials must be undertaken to analyze the probability of successful TFR in patients managed with TKI dose de-escalation strategies before TKI discontinuation,” they concluded.—Hina M. Porcelli
