Immuno-oncological Efficacy of RXDX-106, a Novel TAM (TYRO3, AXL, MER) Family Small-Molecule Kinase Inhibitor

Area of Science:

• Oncology
• Immunology
• Pharmacology

Background:

• TAM receptor tyrosine kinases (RTKs) are linked to cancer progression, metastasis, and drug resistance.
• TAM RTKs can suppress immune responses, aiding cancer cells in evading immune surveillance.
• Expression of AXL and MER, components of TAM RTKs, increases during tumor progression.

Purpose of the Study:

• To characterize the small-molecule RXDX-106 as a selective pan-TAM RTK inhibitor.
• To evaluate the antitumor activity and immune-modulating effects of RXDX-106 in preclinical cancer models.

Main Methods:

• Characterization of RXDX-106's selectivity, potency, and dissociation kinetics.
• Assessment of RXDX-106's tumor growth inhibition (TGI) in syngeneic tumor models (wild-type vs. immunodeficient mice).
• Analysis of immune cell infiltration, polarization, and activation (leukocytes, macrophages, NK cells, CD8+ T cells) post-treatment.

Main Results:

• RXDX-106 demonstrated significant antitumor activity, dependent on the presence of immune cells.
• Treatment led to increased tumor-infiltrating leukocytes, M1-polarized macrophages, and activated NK cells.
• RXDX-106 enhanced CD8+ T cell function and potentiated the efficacy of anti-PD-1 therapy.

Conclusions:

• RXDX-106 is a potent pan-TAM RTK inhibitor with significant antitumor activity.
• The drug activates both innate and adaptive immunity, suggesting a novel therapeutic strategy for various cancers.
• RXDX-106 shows clinical potential, particularly in combination with immune checkpoint inhibitors.