IDH1 and cholangiocarcinoma: Furthermore, since the homologous repair (HR) deficiency conferred by IDH1/2 mutations is known to make cells more sensitive to Poli ADP-ribosio polimerasi (PARP) inhibition, the PARP inhibitor olaparib is currently tested in the phase 2 trial of IDH1/2 mutant relapsed solid tumors, including CCA (NCT03212274).