Identifying Drug Combination Strategies for ZMYM2: FGFR1 Fusion Positive Leukemia.

Area of Science:

• Hematology
• Oncology
• Molecular Biology

Background:

• Myeloid/lymphoid neoplasms with tyrosine kinase gene fusions (MLN-TK) represent a challenging group of leukemias with poor prognosis.
• FGFR1-fusion positive leukemias, previously known as 8p11.2 myeloproliferative syndrome (EMS) or stem cell leukemia/lymphoma (SCLL), are now classified under Myeloid/lymphoid neoplasms with FGFR1 rearrangement.
• Identifying effective therapeutic strategies for MLN-TK is crucial due to their aggressive nature.

Purpose of the Study:

• To explore novel therapeutic options for patients with MLN-TK, specifically focusing on FGFR1-fusion positive cases.
• To evaluate the clinical and ex vivo drug response of a patient with ZMYM2:FGFR1 fusion.
• To investigate the efficacy of FGFR kinase inhibitors and combination therapies in preclinical models.

Main Methods:

• Clinical data and ex vivo drug response of a ZMYM2:FGFR1-positive patient were analyzed.
• Leukemia cells from the patient were tested for sensitivity to various drugs.
• ZMYM2:FGFR1-transformed Ba/F3 cells were used to assess sensitivity to next-generation FGFR inhibitors and drug combinations.

Main Results:

• The patient with ZMYM2:FGFR1 fusion responded initially to ponatinib and later to pemigatinib, preceding a successful transplant.
• Ex vivo analysis showed leukemia cells were sensitive to ponatinib, bortezomib, and axitinib.
• ZMYM2:FGFR1-transformed cells demonstrated high sensitivity to next-generation FGFR inhibitors, with synergistic effects observed when combined with trametinib or midostaurin.

Conclusions:

• FGFR kinase inhibitors represent a viable therapeutic avenue for FGFR1-fusion positive MLN-TK.
• Combination therapies involving FGFR inhibitors show synergistic potential, offering new treatment strategies.
• Targeting FGFR1 fusions provides a promising direction for improving outcomes in this poor-prognosis leukemia.