Disease-related mortality exceeds treatment-related mortality in patients with chronic myeloid leukemia on second-line or later therapy

The Contemporary Role of Hematopoietic Stem Cell Transplantation in the Management of Chronic Myeloid Leukemia: Is It the Same in All Settings?

Hematopoietic stem cell transplantation (HSCT) for chronic myeloid leukemia (CML) patients has transitioned from the standard of care to a treatment option limited to those with unsatisfactory tyrosine kinase inhibitor (TKI) responses and advanced disease stages. In recent years, the threshold for undergoing HSCT has increased. Most CML patients now have life expectancies comparable to the general population, and therefore, the goal of therapy is shifting toward achieving treatment-free remission (TFR). While TKI discontinuation trials in CML show potential for achieving TFR, relapse risk is high, affirming allogeneic HSCT as the sole curative treatment. HSCT should be incorporated into treatment algorithms from the time of diagnosis and, in some patients, evaluated as soon as possible. In this review, we will look at some of the recent advances in HSCT, as well as its indication in the era of aiming for TFR in the presence of TKIs in CML.

No margin for non-adherence: Probabilistic kaplan-meier modeling of imatinib non-adherence and treatment response in CML (ADAGIO study)

BACKGROUND

Although adherence to imatinib is critical for attaining treatment responses in chronic myeloid leukemia, there is evidence of varying adherence among patients. Our aim was to model and determine the margin of tolerance, if any, required to ensure treatment responses among patients prescribed imatinib before treatment response is at risk.

METHOD

We performed post hoc analyses of the ADAGIO study conducted in Belgium on 169 evaluable patients (Blood 2009). Applying Kaplan-Meier methods using adherence instead of the conventional time variable, we modeled the likelihood of complete cytogenetic (CCyR), complete hematological (CHR), major molecular (MMR) and optimal (OR) response as a function of 90-day pill count adherence.

RESULTS

Analyses showed that ∼100 % adherence of prescribed dose is associated with probabilities of 0.84 for CHR, 0.83 for CCyR, 0.82 for OR, and 0.77 for MMR; compared to, 0.37 (CHR and CCyR), 0.35 (OR), and 0.39 (MMR) at 90 % adherence. Increasing intake of imatinib from 90 % to 100 % of the prescribed dose increased the likelihood of the various treatment responses by 1.95-2.35-fold.

CONCLUSION

There is virtually no margin for nonadherence, if the objective is to optimize the likelihood of treatment response, and a minimal margin to avoid impaired treatment response.

Benefits and risks of ponatinib versus bosutinib following treatment failure of two prior tyrosine kinase inhibitors in patients with chronic phase chronic myeloid leukemia: a matching-adjusted indirect comparison

OBJECTIVE

Comparing the benefit-risk profiles of ponatinib vs. bosutinib in third-line (3L) treatment of chronic phase chronic myeloid leukemia (CP-CML) is challenging because their pivotal trials lacked comparator arms. To characterize the overall benefit-risk profile in 3L CP-CML patients treated with bosutinib vs. ponatinib, a matching-adjusted indirect comparison (MAIC) was performed to compare efficacy outcomes and treatment duration after adjusting for trial subjects' baseline characteristics, and tolerability was assessed with an unadjusted comparison of study-drug discontinuation.

METHODS

The MAIC was performed using published data from the pivotal bosutinib trial and the most recent individual-patient-level data on file from the pivotal ponatinib trial.

RESULTS

Responses were more frequent and durable with ponatinib (n = 70 MAIC-adjusted) than with bosutinib (n = 119) - complete cytogenetic response (CCyR): 61% vs. 26%; Kaplan-Meier estimate of maintaining CCyR at 4 years: 89% vs. 54%. Median treatment duration was longer with ponatinib than with bosutinib: 38.4 vs. 8.6 months. Only 9% of ponatinib patients (n = 97 unadjusted) vs. 42% of bosutinib patients discontinued due to death, disease progression or unsatisfactory response; 19% vs. 24% discontinued due to adverse events.

CONCLUSIONS

Based on these surrogate measures of patient benefit-risk profiles, ponatinib appears to provide a net overall benefit vs. bosutinib in 3L CP-CML.

A BCR-ABL1 cutoff of 1.5% at 3 months, determined by the GeneXpert system, predicts an optimal response in patients with chronic myeloid leukemia

In chronic myeloid leukemia (CML) patients, 3-month BCR-ABL1 levels have consistently been correlated with further outcomes. Monitoring molecular responses in CML using the GeneXpert (Cepheid) platform has shown an optimal correlation with standardized RQ-PCR (IS) when measuring BCR-ABL1 levels lower than 10%, as it is not accurate for values over 10%. The aim of the present study was to determine the predictive molecular value at three months on different outcome variables using the Xpert BCR-ABL1 Monitor^TM assay (Xpert BCR-ABL1). We monitored 125 newly diagnosed consecutive CML patients in the chronic phase (CML-CP) using an automated method: Xpert BCR-ABL1. Only 5% of patients did not achieve an optimal response at 3 months, and the 10% BCR-ABL1 cutoff defined by RQ-PCR (IS) methods was unable to identify significant differences in the probabilities of achieving a complete cytogenetic response (CCyR) (50% vs. 87%, p = 0.1) or a major molecular response (MMR) (60% vs. 80%, p = 0.29) by 12 months. In contrast, a cutoff of 1.5% more accurately identified differences in the probabilities of achieving CCyR (98% vs. 54%, p<0.001) and MMR (88% vs. 56%, p<0.001) by 12 months, as well as probabilities of treatment changes (p = 0.005). Therefore, when using the Xpert BCR-ABL1 assay, a cutoff of 1.5% at 3 months could with high probability identify patients able to achieve an optimal response at 12 months.

lncRNA UCA1 Contributes to Imatinib Resistance by Acting as a ceRNA Against miR-16 in Chronic Myeloid Leukemia Cells

Imatinib (IM) has been applied to the chronic phase of chronic myeloid leukemia (CML) and has great benefit on the prognosis of patients with CML. The function of drug efflux mediated by multidrug resistance protein-1 (MDR1) is considered as a main reason for IM drug resistance in CML cells. However, the exact mechanisms of MDR1 modulation in IM resistance of CML cells remain unclear. In the present study, long noncoding RNA (lncRNA) UCA1 was identified as an important modulator of MDR1 by a model system of leukemia cell lines with a gradual increase of MDR1 expression and IM resistance. Overexpression of UCA1 increased MDR1 expression to promote IM resistance of CML cells. Furthermore, for the first time, we demonstrated that UCA1 functions as a competitive endogenous (ceRNA) of MDR1 through completely binding the common miR-16. UCA1-MDR1 might be a novel target for enhancing the therapeutic efficacy of CML patients with IM resistance.