PARP4 inhibitor

Although adaptive resistance mechanisms re-emerge, PARP14 inhibition combined with PD-1 blockade offers a promising strategy to enhance treatment outcomes and overcome ICI resistance in melanoma, as immune cells are primed for further therapeutic interventions that leverage the quiescent state.

Effector T cell infiltration is enhanced in tumours derived from cells pre-treated with IFNγ in immunocompetent female mice when PARP14 is pharmacologically inhibited or knocked down, while the presence of regulatory T cells is decreased, leading to restoration of α-PD-1 sensitivity. Finally, we determine that tumours which spontaneously relapse in immunocompetent female mice following α-PD-1 therapy upregulate IFNγ signalling and can also be re-sensitised upon receiving PARP14 inhibitor treatment, establishing PARP14 as an actionable target to reverse IFNγ-driven ICBT resistance.

Knockdown or pharmacological inhibition of PARP14 increased effector T cell infiltration into tumors derived from cells pre-treated with IFNγ and decreased the presence of regulatory T cells, leading to restoration of α-PD-1 sensitivity. Finally, we determined that tumors which spontaneously relapsed following α-PD-1 therapy could be re-sensitized upon receiving PARP14 inhibitor treatment, establishing PARP14 as an actionable target to reverse IFNγ-driven ICBT resistance.