TKI discontinuation in CML: how do we make more patients eligible? How do we increase the chances of a successful treatment-free remission?

Integrated functional genomic screening to bypass TKI resistance in chronic myeloid leukemia

CML is readily treatable with tyrosine kinase inhibitors (TKIs); however, resistance occurs, with the disease curable in only ∼15%-20% of patients. Using integrated functional genomics, Adnan Awad et al.1 identify agents effective against CML stem cells and describe mechanisms underlying TKI resistance.

Histiocytic neoplasms: Going, going, but not quite gone

BRAF and MEK inhibitors have revolutionised the treatment of patients with high-risk histiocytic neoplasms but does a complete response mean that treatment can be withdrawn? Commentary on: Reiner et al. Outcomes after interruption of targeted therapy in patients with histiocytic neoplasms. Br J Haematol 2023;203:389-394.

Deep molecular response in patients with chronic phase chronic myeloid leukemia treated with the plasminogen activator inhibitor-1 inhibitor TM5614 combined with a tyrosine kinase inhibitor

BACKGROUND

We recently showed that pharmacological inhibition of plasminogen activator inhibitor-1 (PAI-1) activity, based on TM5614, increases cell motility and induces the detachment of hematopoietic stem cells from their niches. In this TM5614 phase II clinical trial, we investigated whether the combination of a PAI-1 inhibitor and tyrosine kinase inhibitors (TKIs) would induce a deep molecular response (DMR) in patients affected by chronic myeloid leukemia (CML) by quantifying BCR-ABL1 transcripts.

METHODS

Patients with chronic phase CML treated with a stable daily dose of TKIs for at least 1 year and yielding a major molecular response (MMR) but not achieving MR^4.5 were eligible for this study. After inclusion, patients began to receive TM5614 as well as a TKI. The primary objective was an evaluation of the cumulative incidence of patient progression from an MMR/MR⁴ to MR^4.5 by 12 months.

RESULTS

Thirty-three patients were enrolled in the study. The median age was 59.0 years and 58% were male. No Sokal high-risk patients were enrolled in this trial. The median TKI treatment duration was 4.8 years. At the start of this study, seven patients and 26 patients received imatinib and second-generation TKIs, respectively. The cumulative MR^4.5 incidence by 12 months was 33.3% (95% confidence interval, 18.0%-51.8%). The cumulative MR^4.5 spontaneous conversion over 12 months was estimated as 8% with TKIs alone based on historical controls. The halving time of BCR-ABL1 at 2 months was significantly shorter for patients who achieved an MR^4.5 , by 12 months than for the other patients (cutoff value: 48 days; sensitivity: 0.80; specificity: 0.91; ROC-AUC: 0.83). During this study, bleeding events and abnormal coagulation related to the drug were not reported, and TM5614 was found to be highly safe.

CONCLUSION

TM5614 combined with TKI was well tolerated and induced MR^4.5 in more patients than stand-alone TKI treatment.

Successful eradication of chronic myeloid leukemia in a child despite allogeneic graft rejection

Background

Chronic myeloid leukemia (CML) is a rare disease in children and treated with tyrosine kinase inhibitors (TKI) and with allogeneic hematopoietic stem cell transplantation (HSCT) still in many cases.

Case

We describe an 8‐year‐old patient with CML treated with two different TKIs before proceeding to allogeneic HSCT. Despite successful engraftment, prompt rejection of the graft was followed by autologous reconstitution. TKI therapy was reintroduced post‐rejection in anticipation of relapse but shortly discontinued due to low white blood cell and neutrophil counts. The patient has remained disease‐free over 5 years after graft rejection and without further therapy.

Conclusion

This case suggests that even a short antileukemic effect by an allogeneic transplant may succeed in eradicating CML.