MAP2K7 and paronychia: In addition, there is evidence of MAPK pathway inhibition without the class effects seen with MEK inhibitors (e.g., decreased left ventricular ejection fraction, retinal vein obstruction/central serous retinopathy, acneiform rash, paronychia).The long plasma half-life of tovorafenib affords use with a QW dosing schedule, while still maintaining a steady state trough plasma concentration above the protein binding adjusted pERK EC50 inhibition level.