Digital droplet PCR as a predictive tool for successful discontinuation outcome in chronic myeloid leukemia: Is it time to introduce it in the clinical practice?

Tyrosine kinase inhibitors (TKIs) have drastically changed the outcome of chronic myeloid leukemia (CML) patients. A sustained and deep molecular response achieved over time paves the way to therapy discontinuation, and is a pre-requisite to attempt treatment-free remission. Monitoring of the molecular response during treatment discontinuation is routinely carried out by RQ-PCR, but it may not be the optimal tool to monitor minimal residual disease at the time of stopping treatment and during treatment discontinuation. Different digital PCR platforms (such as droplet dPCR) are available, a method based on water-emulsion droplet technology in which the sample is partitioned into 20,000 droplets and PCR amplification of the template subsequently occurs in each individual droplet. The consequent high sensitivity and precision with a very reliable quantification without the need of a calibration curve and the exquisite reproducibility makes this procedure as an ideal alternative method for the detection of very low levels of disease. Aim of this review is to describe and discuss the recent use of dPCR/ddPCR in CML, focusing in particular on its role in TKI treatment discontinuation strategies.

Incidence of Clinically Significant (≤10 g/dL) Late Anemia in Elderly Patients with Newly Diagnosed Chronic Myeloid Leukemia Treated with Imatinib.

BACKGROUND: In elderly patients with chronic myeloid leukemia (CML) responsive to imatinib, the incidence of clinically significant (CS) late chronic anemia is still unknown. MATERIALS AND METHODS: To highlight this issue, we revised retrospectively 81 CML patients aged >60 years treated at our Institution with front-line imatinib for at least 24 months in durable complete cytogenetic response (CCyR). CS late chronic anemia was defined as the presence of persistent (>6 months) and otherwise unexplained Hb levels ≤10 g/dL, which occurred >6 months from imatinib start. RESULTS: A condition of CS late chronic anemia occurred in 22 out of 81 patients (27.2%) at different intervals from imatinib start. Seven out of 22 patients (31.8%) needed packed red cell transfusions during the follow-up. At diagnosis, patients who developed CS late chronic anemia were significantly older and had a lower Hb median level. Six out of 22 patients with CS late chronic anemia received subcutaneous recombinant alpha-erythropoietin (EPO) at the standard dosage of 40,000 IU weekly: all 6 patients achieved an erythroid response. A significantly worse event-free survival (EFS) in patients with untreated CS late chronic anemia was observed (p = 0.012). CONCLUSIONS: CS late chronic anemia during long-term treatment with imatinib is a common complication in responsive elderly patients, with worse EFS if untreated. Results with EPO are encouraging, but larger studies are warranted to define its role.

Clinical results according to age in patients with chronic myeloid leukemia receiving imatinib frontline: The younger, the later, the worse?

OBJECTIVES: To evaluate differences in clinical results according to age among patients with chronic myeloid leukemia (CML). METHODS: 207 consecutive CML patients treated with imatinib frontline were revised, dividing them in young adults (>20 < 45 years) (YA), middle-aged adults (≥45 < 65 years) (MA) and elderly (≥65 years) (EL). RESULTS: Cumulative incidence of complete cytogenetic response (CCyR) and major molecular response (MMolR) were significantly higher in MA compared with YA and EL (P < .001 for CCyR and P = .001 for MMolR). Number of total events was lower in MA (8 [11.1%] vs 21 [34.4%] in YA and 28 [37.8%] in EL, P = .001): no difference was observed for blastic evolution (P = .478). Number of deaths was higher in the EL (12 [16.2%] vs 2 [3.2%] in YA and 0 in MA, P < .001): however, 11/12 deaths in EL were not related to CML. The PFS curve in MA was significantly longer than in YA and in EL (P = .02). The OS curve in EL was significantly shorter than in YA and in MA (P < .001). CONCLUSIONS: Age at diagnosis influences significantly the course of CML patients treated with imatinib: a possible explanation of the counterintuitive worse course in YA is the delayed diagnosis compared to elderly.

Impact of exclusion criteria for the DASISION and ENESTnd trials in the front-line treatment of a 'real-life' patient population with chronic myeloid leukaemia.

Both Dasision and ENESTnd trials had many exclusion criteria, with a possible selection bias compared with the real-life. To address the impact of this bias on the first-line treatment in the current clinical practice, we revised 207 unselected newly diagnosed chronic phase chronic myeloid leukaemia (CML) patients [M/F 108/99, median age 58.8 years, interquartile range 42.3-70.2] treated with front-line imatinib from June 2002 to June 2013 at our Institution, and evaluated how many of them would have been excluded from enrolment in the two trials. Twenty-eight patients (13.5%) should have been excluded by both trials because of polycomorbidities (12), severe cardiomyopathy (five), age > 80 with frailty (three), drug abuse (two) or other severe concomitant diseases (six). In addition, eight patients should have been excluded by Dasision due to isolated chronic obstructive broncopulmonar disease, and 19 patients should have been excluded by ENESTnd due to isolated diabetes (10), arrhythmia (four), acute myocardial infarction > 6 months before CML diagnosis (two), chronic pancreatic disease (two) and peripheral arterial obstructive disease (one). On the whole, 36 patients (17.4%) would have been excluded by Dasision trial and 47 (22.7%) by ENESTnd trial. The patients potentially not eligible for both trials were significantly older and with imatinib had a worse outcome compared with patients potentially eligible. Our data highlight that an automatic transposition of results available in clinical controlled trials into the frontline real-life management of CML patients should be regarded with caution. Copyright © 2015 John Wiley & Sons, Ltd.

Influence of time to complete remission and duration of all-trans retinoic acid therapy on the relapse risk in patients with acute promyelocytic leukemia receiving AIDA protocols.

Despite the impressive results obtained with standard chemotherapy, approximately 20% of acute promyelocytic leukemia (APL) patients undergo disease relapse thereby requiring salvage therapy. Few data is available on long-term prognosis in relation to time to complete remission (CR): we reviewed 142 patients treated with AIDA protocols and we found that 42 out of 142 (29.6%) patients achieved CR after 35 days (median time, 42 days). No significant differences in presenting features, including FAB subtype, type of PML/RARA transcript and relapse risk at presentation between the two patient groups achieving CR > or <35 days were revealed, except for male sex and older age that were significantly associated with delayed CR. Rate of relapse was 31% in patients with delayed CR compared to 17% in the group of patients who achieved CR<35 days (p=0.001), with a 5-year CIR of 29.6% compared to 12% (p=0.03). APL patients with delayed CR should be more closely monitored during follow-up for early identification of relapse and prompt administration of pre-emptive salvage therapy.