Samples of the monolithic silicon pixel ASIC prototypeproduced in 2022 within the framework of the Horizon 2020 MONOLITHERC Advanced project were irradiated with 70 MeV protons up to afluence of1 ×10$^{16}$ n$_{eq}$/cm$^{2}$, and then tested using a beam of120 GeV/c pions. The ASIC contains a matrix of 100 μm pitchhexagonal pixels, read out by low noise and very fast frontendelectronics produced in a 130 nm SiGe BiCMOS technology process.The dependence on the proton fluence of the efficiency and the timeresolution of this prototype was measured with the frontendelectronics operated at a power density between 0.13 and0.9 W/cm$^{2}$. The testbeam data show that the detection efficiencyof 99.96% measured at sensor bias voltage of 200 V beforeirradiation becomes 96.2% after a fluence of1 ×10$^{16}$ n$_{eq}$/cm$^{2}$. An increase of the sensor biasvoltage to 300 V provides an efficiency to 99.7% at that protonfluence. The timing resolution of 20 ps measured beforeirradiation rises for a proton fluence of1 ×10$^{16}$ n$_{eq}$/cm$^{2}$ to 53 and 45 ps at HV = 200and 300 V, respectively.