Model-Based Inference and Classification of Immunologic Control Mechanisms from TKI Cessation and Dose Reduction in Patients with CML

Recent clinicalfindings in patients with chronic myeloid leukemia (CML) suggest that the risk of molecular recurrence after stopping tyrosine kinase inhibitor (TKI) treatment substantially depends on an individual's leukemia-specific immune response. However, it is still not possible to prospectively identify patients that will remain in treatment-free remission (TFR). Here, we used an ordinary differential equation model for CML, which explicitly includes an antileukemic immunologic effect, and applied it to 21 patients with CML for whom BCR-ABL1/ABL1 time courses had been quantified before and after TKI cessation. Immunologic control was conceptually necessary to explain TFR as observed in about half of the patients. Fitting the model simulations to data, we identified patient-specific parameters and classified patients into three different groups according to their predicted immune system configuration ("immunologic landscapes"). While one class of patients required complete CML eradication to achieve TFR, other patients were able to control residual leukemia levels after treatment cessation. Amongthem were a third class of patients that maintained TFR only if an optimal balance between leukemia abundance and immunologic activation was achieved before treatment cessation. Model simulations further suggested that changes in the BCR-ABL1 dynamics resulting from TKI dose reduction convey information about the patient-specific immune system and allow prediction of outcome after treatment cessation. This inference of individual immunologic configurations based on treatment alterations can also be applied to other cancer types in which the endogenous immune system supports maintenance therapy, long-term disease control, or even cure. Significance: This mathematical modeling approach provides strong evidence that different immunologic configurations in patients with CML determine their response to therapy cessation and that dose reductions can help to prospectively infer different risk groups.Peer reviewe

Preclinical evaluation of Imatinib does not support its use as an antiviral drug against SARS-CoV-2

Following the emergence of SARS-CoV-2, the search for an effective and rapidly available treatment was initiated worldwide based on repurposing of available drugs. Previous reports described the antiviral activity of certain tyrosine kinase inhibitors (TKIs) targeting the Abelson kinase 2 against pathogenic coronaviruses. Imatinib, one of them, has more than twenty years of safe utilization for the treatment of hematological malignancies. In this context, Imatinib was rapidly evaluated in clinical trials against Covid-19. Here, we present the pre-clinical evaluation of imatinib in multiple models. Our results indicated that imatinib and another TKI, the masitinib, exhibit an antiviral activity in VeroE6 cells. However, imatinib was inactive in a reconstructed bronchial human airway epithelium model. In vivo, imatinib therapy failed to impair SARS-CoV-2 replication in a golden Syrian hamster model despite high concentrations in plasma and in the lung. Overall, these results do not support the use of imatinib and similar TKIs as antivirals in the treatment of Covid-19

Molecular status 36 months after TKI discontinuation in CML is highly predictive for subsequent loss of MMR-final report from AFTER-SKI

Non peer reviewe

Impact of age on efficacy and toxicity of nilotinib in patients with chronic myeloid leukemia in chronic phase : ENEST1st subanalysis

Purpose Achievement of deep molecular response with a tyrosine kinase inhibitor in patients with chronic myeloid leukemia (CML) is required to attempt discontinuation of therapy in these patients. The current subanalysis from the Evaluating Nilotinib Efficacy and Safety in Clinical Trials as First-Line Treatment (ENEST1st) study evaluated whether age has an impact on the achievement of deeper molecular responses or safety with frontline nilotinib in patients with CML. Methods ENEST1st is an open-label, multicenter, single-arm, prospective study of nilotinib 300 mg twice daily in patients with newly diagnosed CML in chronic phase. The patients were stratified into the following 4 groups based on age: young (18-39 years), middle age (40-59 years), elderly (60-74 years), and old (>= 75 years). The primary end point was the rate of molecular response 4 ([MR4] BCR-ABL1 Results Of the 1091 patients enrolled, 1089 were considered in the analysis, of whom, 23% (n = 243), 45% (n = 494), 27% (n = 300), and 5% (n = 52) were categorized as young, middle age, elderly, and old, respectively. At 18 months, the rates of MR4 were 33.9% (95% confidence interval [CI], 27.8-40.0%) in the young, 39.6% (95% CI, 35.3-44.0%) in the middle-aged, 40.5% (95% CI, 34.8-46.1%) in the elderly, and 35.4% (95% CI, 21.9-48.9%) in the old patients. Although the incidence of adverse events was slightly different, no new specific safety signals were observed across the 4 age groups. Conclusions This subanalysis of the ENEST1st study showed that age did not have a relevant impact on the deep molecular response rates associated with nilotinib therapy in newly diagnosed patients with CML and eventually on the eligibility of the patients to attempt treatment discontinuation.Peer reviewe

Second attempt to discontinue imatinib in CP-CML patients with a second sustained complete molecular response.

International audienc

A tyrosine kinase-STAT5-miR21-PDCD4 regulatory axis in chronic and acute myeloid leukemia cells

MicroRNAs (miRNAs) are regulators of several key patho-physiological processes, including cell cycle and apoptosis. Using microarray-based miRNA profiling in K562 cells, a model of chronic myeloid leukemia (CML), we found that the oncoprotein BCR-ABL1 regulates the expression of miR-21, an "onco-microRNA", found to be overexpressed in several cancers. This effect relies on the presence of two STAT binding sites on the promoter of miR-21, and on the phosphorylation status of STAT5, a transcription factor activated by the kinase activity of BCR-ABL1. Mir-21 regulates the expression of PDCD4 (programmed cell death protein 4), a tumor suppressor identified through a proteomics approach. The phosphoSTAT5 - miR-21 - PDCD4 pathway was active in CML primary CD34(+) cells, but also in acute myeloid leukemia (AML) models like MV4.11 and MOLM13, where the constitutively active tyrosine kinase FLT3-ITD plays a similar role to BCR-ABL1 in the K562 cell line